security/selinux/ss/services.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Implementation of the security services.
   4  *
   5  * Authors : Stephen Smalley, <stephen.smalley.work@gmail.com>
   6  *           James Morris <jmorris@redhat.com>
   7  *
   8  * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
   9  *
  10  *      Support for enhanced MLS infrastructure.
  11  *      Support for context based audit filters.
  12  *
  13  * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
  14  *
  15  *      Added conditional policy language extensions
  16  *
  17  * Updated: Hewlett-Packard <paul@paul-moore.com>
  18  *
  19  *      Added support for NetLabel
  20  *      Added support for the policy capability bitmap
  21  *
  22  * Updated: Chad Sellers <csellers@tresys.com>
  23  *
  24  *  Added validation of kernel classes and permissions
  25  *
  26  * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
  27  *
  28  *  Added support for bounds domain and audit messaged on masked permissions
  29  *
  30  * Updated: Guido Trentalancia <guido@trentalancia.com>
  31  *
  32  *  Added support for runtime switching of the policy type
  33  *
  34  * Copyright (C) 2008, 2009 NEC Corporation
  35  * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
  36  * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  37  * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
  38  * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
  39  */
  40 #include <linux/kernel.h>
  41 #include <linux/slab.h>
  42 #include <linux/string.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/rcupdate.h>
  45 #include <linux/errno.h>
  46 #include <linux/in.h>
  47 #include <linux/sched.h>
  48 #include <linux/audit.h>
  49 #include <linux/vmalloc.h>
  50 #include <linux/lsm_hooks.h>
  51 #include <net/netlabel.h>
  52
  53 #include "flask.h"
  54 #include "avc.h"
  55 #include "avc_ss.h"
  56 #include "security.h"
  57 #include "context.h"
  58 #include "policydb.h"
  59 #include "sidtab.h"
  60 #include "services.h"
  61 #include "conditional.h"
  62 #include "mls.h"
  63 #include "objsec.h"
  64 #include "netlabel.h"
  65 #include "xfrm.h"
  66 #include "ebitmap.h"
  67 #include "audit.h"
  68 #include "policycap_names.h"
  69 #include "ima.h"
  70
  71 struct selinux_policy_convert_data {
  72         struct convert_context_args args;
  73         struct sidtab_convert_params sidtab_params;
  74 };
  75
  76 /* Forward declaration. */
  77 static int context_struct_to_string(struct policydb *policydb,
  78                                     struct context *context,
  79                                     char **scontext,
  80                                     u32 *scontext_len);
  81
  82 static int sidtab_entry_to_string(struct policydb *policydb,
  83                                   struct sidtab *sidtab,
  84                                   struct sidtab_entry *entry,
  85                                   char **scontext,
  86                                   u32 *scontext_len);
  87
  88 static void context_struct_compute_av(struct policydb *policydb,
  89                                       struct context *scontext,
  90                                       struct context *tcontext,
  91                                       u16 tclass,
  92                                       struct av_decision *avd,
  93                                       struct extended_perms *xperms);
  94
  95 static int selinux_set_mapping(struct policydb *pol,
  96                                const struct security_class_mapping *map,
  97                                struct selinux_map *out_map)
  98 {
  99         u16 i, j;
 100         bool print_unknown_handle = false;
 101
 102         /* Find number of classes in the input mapping */
 103         if (!map)
 104                 return -EINVAL;
 105         i = 0;
 106         while (map[i].name)
 107                 i++;
 108
 109         /* Allocate space for the class records, plus one for class zero */
 110         out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
 111         if (!out_map->mapping)
 112                 return -ENOMEM;
 113
 114         /* Store the raw class and permission values */
 115         j = 0;
 116         while (map[j].name) {
 117                 const struct security_class_mapping *p_in = map + (j++);
 118                 struct selinux_mapping *p_out = out_map->mapping + j;
 119                 u16 k;
 120
 121                 /* An empty class string skips ahead */
 122                 if (!strcmp(p_in->name, "")) {
 123                         p_out->num_perms = 0;
 124                         continue;
 125                 }
 126
 127                 p_out->value = string_to_security_class(pol, p_in->name);
 128                 if (!p_out->value) {
 129                         pr_info("SELinux:  Class %s not defined in policy.\n",
 130                                p_in->name);
 131                         if (pol->reject_unknown)
 132                                 goto err;
 133                         p_out->num_perms = 0;
 134                         print_unknown_handle = true;
 135                         continue;
 136                 }
 137
 138                 k = 0;
 139                 while (p_in->perms[k]) {
 140                         /* An empty permission string skips ahead */
 141                         if (!*p_in->perms[k]) {
 142                                 k++;
 143                                 continue;
 144                         }
 145                         p_out->perms[k] = string_to_av_perm(pol, p_out->value,
 146                                                             p_in->perms[k]);
 147                         if (!p_out->perms[k]) {
 148                                 pr_info("SELinux:  Permission %s in class %s not defined in policy.\n",
 149                                        p_in->perms[k], p_in->name);
 150                                 if (pol->reject_unknown)
 151                                         goto err;
 152                                 print_unknown_handle = true;
 153                         }
 154
 155                         k++;
 156                 }
 157                 p_out->num_perms = k;
 158         }
 159
 160         if (print_unknown_handle)
 161                 pr_info("SELinux: the above unknown classes and permissions will be %s\n",
 162                        pol->allow_unknown ? "allowed" : "denied");
 163
 164         out_map->size = i;
 165         return 0;
 166 err:
 167         kfree(out_map->mapping);
 168         out_map->mapping = NULL;
 169         return -EINVAL;
 170 }
 171
 172 /*
 173  * Get real, policy values from mapped values
 174  */
 175
 176 static u16 unmap_class(struct selinux_map *map, u16 tclass)
 177 {
 178         if (tclass < map->size)
 179                 return map->mapping[tclass].value;
 180
 181         return tclass;
 182 }
 183
 184 /*
 185  * Get kernel value for class from its policy value
 186  */
 187 static u16 map_class(struct selinux_map *map, u16 pol_value)
 188 {
 189         u16 i;
 190
 191         for (i = 1; i < map->size; i++) {
 192                 if (map->mapping[i].value == pol_value)
 193                         return i;
 194         }
 195
 196         return SECCLASS_NULL;
 197 }
 198
 199 static void map_decision(struct selinux_map *map,
 200                          u16 tclass, struct av_decision *avd,
 201                          int allow_unknown)
 202 {
 203         if (tclass < map->size) {
 204                 struct selinux_mapping *mapping = &map->mapping[tclass];
 205                 unsigned int i, n = mapping->num_perms;
 206                 u32 result;
 207
 208                 for (i = 0, result = 0; i < n; i++) {
 209                         if (avd->allowed & mapping->perms[i])
 210                                 result |= (u32)1<<i;
 211                         if (allow_unknown && !mapping->perms[i])
 212                                 result |= (u32)1<<i;
 213                 }
 214                 avd->allowed = result;
 215
 216                 for (i = 0, result = 0; i < n; i++)
 217                         if (avd->auditallow & mapping->perms[i])
 218                                 result |= (u32)1<<i;
 219                 avd->auditallow = result;
 220
 221                 for (i = 0, result = 0; i < n; i++) {
 222                         if (avd->auditdeny & mapping->perms[i])
 223                                 result |= (u32)1<<i;
 224                         if (!allow_unknown && !mapping->perms[i])
 225                                 result |= (u32)1<<i;
 226                 }
 227                 /*
 228                  * In case the kernel has a bug and requests a permission
 229                  * between num_perms and the maximum permission number, we
 230                  * should audit that denial
 231                  */
 232                 for (; i < (sizeof(u32)*8); i++)
 233                         result |= (u32)1<<i;
 234                 avd->auditdeny = result;
 235         }
 236 }
 237
 238 int security_mls_enabled(void)
 239 {
 240         int mls_enabled;
 241         struct selinux_policy *policy;
 242
 243         if (!selinux_initialized())
 244                 return 0;
 245
 246         rcu_read_lock();
 247         policy = rcu_dereference(selinux_state.policy);
 248         mls_enabled = policy->policydb.mls_enabled;
 249         rcu_read_unlock();
 250         return mls_enabled;
 251 }
 252
 253 /*
 254  * Return the boolean value of a constraint expression
 255  * when it is applied to the specified source and target
 256  * security contexts.
 257  *
 258  * xcontext is a special beast...  It is used by the validatetrans rules
 259  * only.  For these rules, scontext is the context before the transition,
 260  * tcontext is the context after the transition, and xcontext is the context
 261  * of the process performing the transition.  All other callers of
 262  * constraint_expr_eval should pass in NULL for xcontext.
 263  */
 264 static int constraint_expr_eval(struct policydb *policydb,
 265                                 struct context *scontext,
 266                                 struct context *tcontext,
 267                                 struct context *xcontext,
 268                                 struct constraint_expr *cexpr)
 269 {
 270         u32 val1, val2;
 271         struct context *c;
 272         struct role_datum *r1, *r2;
 273         struct mls_level *l1, *l2;
 274         struct constraint_expr *e;
 275         int s[CEXPR_MAXDEPTH];
 276         int sp = -1;
 277
 278         for (e = cexpr; e; e = e->next) {
 279                 switch (e->expr_type) {
 280                 case CEXPR_NOT:
 281                         BUG_ON(sp < 0);
 282                         s[sp] = !s[sp];
 283                         break;
 284                 case CEXPR_AND:
 285                         BUG_ON(sp < 1);
 286                         sp--;
 287                         s[sp] &= s[sp + 1];
 288                         break;
 289                 case CEXPR_OR:
 290                         BUG_ON(sp < 1);
 291                         sp--;
 292                         s[sp] |= s[sp + 1];
 293                         break;
 294                 case CEXPR_ATTR:
 295                         if (sp == (CEXPR_MAXDEPTH - 1))
 296                                 return 0;
 297                         switch (e->attr) {
 298                         case CEXPR_USER:
 299                                 val1 = scontext->user;
 300                                 val2 = tcontext->user;
 301                                 break;
 302                         case CEXPR_TYPE:
 303                                 val1 = scontext->type;
 304                                 val2 = tcontext->type;
 305                                 break;
 306                         case CEXPR_ROLE:
 307                                 val1 = scontext->role;
 308                                 val2 = tcontext->role;
 309                                 r1 = policydb->role_val_to_struct[val1 - 1];
 310                                 r2 = policydb->role_val_to_struct[val2 - 1];
 311                                 switch (e->op) {
 312                                 case CEXPR_DOM:
 313                                         s[++sp] = ebitmap_get_bit(&r1->dominates,
 314                                                                   val2 - 1);
 315                                         continue;
 316                                 case CEXPR_DOMBY:
 317                                         s[++sp] = ebitmap_get_bit(&r2->dominates,
 318                                                                   val1 - 1);
 319                                         continue;
 320                                 case CEXPR_INCOMP:
 321                                         s[++sp] = (!ebitmap_get_bit(&r1->dominates,
 322                                                                     val2 - 1) &&
 323                                                    !ebitmap_get_bit(&r2->dominates,
 324                                                                     val1 - 1));
 325                                         continue;
 326                                 default:
 327                                         break;
 328                                 }
 329                                 break;
 330                         case CEXPR_L1L2:
 331                                 l1 = &(scontext->range.level[0]);
 332                                 l2 = &(tcontext->range.level[0]);
 333                                 goto mls_ops;
 334                         case CEXPR_L1H2:
 335                                 l1 = &(scontext->range.level[0]);
 336                                 l2 = &(tcontext->range.level[1]);
 337                                 goto mls_ops;
 338                         case CEXPR_H1L2:
 339                                 l1 = &(scontext->range.level[1]);
 340                                 l2 = &(tcontext->range.level[0]);
 341                                 goto mls_ops;
 342                         case CEXPR_H1H2:
 343                                 l1 = &(scontext->range.level[1]);
 344                                 l2 = &(tcontext->range.level[1]);
 345                                 goto mls_ops;
 346                         case CEXPR_L1H1:
 347                                 l1 = &(scontext->range.level[0]);
 348                                 l2 = &(scontext->range.level[1]);
 349                                 goto mls_ops;
 350                         case CEXPR_L2H2:
 351                                 l1 = &(tcontext->range.level[0]);
 352                                 l2 = &(tcontext->range.level[1]);
 353                                 goto mls_ops;
 354 mls_ops:
 355                                 switch (e->op) {
 356                                 case CEXPR_EQ:
 357                                         s[++sp] = mls_level_eq(l1, l2);
 358                                         continue;
 359                                 case CEXPR_NEQ:
 360                                         s[++sp] = !mls_level_eq(l1, l2);
 361                                         continue;
 362                                 case CEXPR_DOM:
 363                                         s[++sp] = mls_level_dom(l1, l2);
 364                                         continue;
 365                                 case CEXPR_DOMBY:
 366                                         s[++sp] = mls_level_dom(l2, l1);
 367                                         continue;
 368                                 case CEXPR_INCOMP:
 369                                         s[++sp] = mls_level_incomp(l2, l1);
 370                                         continue;
 371                                 default:
 372                                         BUG();
 373                                         return 0;
 374                                 }
 375                                 break;
 376                         default:
 377                                 BUG();
 378                                 return 0;
 379                         }
 380
 381                         switch (e->op) {
 382                         case CEXPR_EQ:
 383                                 s[++sp] = (val1 == val2);
 384                                 break;
 385                         case CEXPR_NEQ:
 386                                 s[++sp] = (val1 != val2);
 387                                 break;
 388                         default:
 389                                 BUG();
 390                                 return 0;
 391                         }
 392                         break;
 393                 case CEXPR_NAMES:
 394                         if (sp == (CEXPR_MAXDEPTH-1))
 395                                 return 0;
 396                         c = scontext;
 397                         if (e->attr & CEXPR_TARGET)
 398                                 c = tcontext;
 399                         else if (e->attr & CEXPR_XTARGET) {
 400                                 c = xcontext;
 401                                 if (!c) {
 402                                         BUG();
 403                                         return 0;
 404                                 }
 405                         }
 406                         if (e->attr & CEXPR_USER)
 407                                 val1 = c->user;
 408                         else if (e->attr & CEXPR_ROLE)
 409                                 val1 = c->role;
 410                         else if (e->attr & CEXPR_TYPE)
 411                                 val1 = c->type;
 412                         else {
 413                                 BUG();
 414                                 return 0;
 415                         }
 416
 417                         switch (e->op) {
 418                         case CEXPR_EQ:
 419                                 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
 420                                 break;
 421                         case CEXPR_NEQ:
 422                                 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
 423                                 break;
 424                         default:
 425                                 BUG();
 426                                 return 0;
 427                         }
 428                         break;
 429                 default:
 430                         BUG();
 431                         return 0;
 432                 }
 433         }
 434
 435         BUG_ON(sp != 0);
 436         return s[0];
 437 }
 438
 439 /*
 440  * security_dump_masked_av - dumps masked permissions during
 441  * security_compute_av due to RBAC, MLS/Constraint and Type bounds.
 442  */
 443 static int dump_masked_av_helper(void *k, void *d, void *args)
 444 {
 445         struct perm_datum *pdatum = d;
 446         char **permission_names = args;
 447
 448         BUG_ON(pdatum->value < 1 || pdatum->value > 32);
 449
 450         permission_names[pdatum->value - 1] = (char *)k;
 451
 452         return 0;
 453 }
 454
 455 static void security_dump_masked_av(struct policydb *policydb,
 456                                     struct context *scontext,
 457                                     struct context *tcontext,
 458                                     u16 tclass,
 459                                     u32 permissions,
 460                                     const char *reason)
 461 {
 462         struct common_datum *common_dat;
 463         struct class_datum *tclass_dat;
 464         struct audit_buffer *ab;
 465         char *tclass_name;
 466         char *scontext_name = NULL;
 467         char *tcontext_name = NULL;
 468         char *permission_names[32];
 469         int index;
 470         u32 length;
 471         bool need_comma = false;
 472
 473         if (!permissions)
 474                 return;
 475
 476         tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
 477         tclass_dat = policydb->class_val_to_struct[tclass - 1];
 478         common_dat = tclass_dat->comdatum;
 479
 480         /* init permission_names */
 481         if (common_dat &&
 482             hashtab_map(&common_dat->permissions.table,
 483                         dump_masked_av_helper, permission_names) < 0)
 484                 goto out;
 485
 486         if (hashtab_map(&tclass_dat->permissions.table,
 487                         dump_masked_av_helper, permission_names) < 0)
 488                 goto out;
 489
 490         /* get scontext/tcontext in text form */
 491         if (context_struct_to_string(policydb, scontext,
 492                                      &scontext_name, &length) < 0)
 493                 goto out;
 494
 495         if (context_struct_to_string(policydb, tcontext,
 496                                      &tcontext_name, &length) < 0)
 497                 goto out;
 498
 499         /* audit a message */
 500         ab = audit_log_start(audit_context(),
 501                              GFP_ATOMIC, AUDIT_SELINUX_ERR);
 502         if (!ab)
 503                 goto out;
 504
 505         audit_log_format(ab, "op=security_compute_av reason=%s "
 506                          "scontext=%s tcontext=%s tclass=%s perms=",
 507                          reason, scontext_name, tcontext_name, tclass_name);
 508
 509         for (index = 0; index < 32; index++) {
 510                 u32 mask = (1 << index);
 511
 512                 if ((mask & permissions) == 0)
 513                         continue;
 514
 515                 audit_log_format(ab, "%s%s",
 516                                  need_comma ? "," : "",
 517                                  permission_names[index]
 518                                  ? permission_names[index] : "????");
 519                 need_comma = true;
 520         }
 521         audit_log_end(ab);
 522 out:
 523         /* release scontext/tcontext */
 524         kfree(tcontext_name);
 525         kfree(scontext_name);
 526 }
 527
 528 /*
 529  * security_boundary_permission - drops violated permissions
 530  * on boundary constraint.
 531  */
 532 static void type_attribute_bounds_av(struct policydb *policydb,
 533                                      struct context *scontext,
 534                                      struct context *tcontext,
 535                                      u16 tclass,
 536                                      struct av_decision *avd)
 537 {
 538         struct context lo_scontext;
 539         struct context lo_tcontext, *tcontextp = tcontext;
 540         struct av_decision lo_avd;
 541         struct type_datum *source;
 542         struct type_datum *target;
 543         u32 masked = 0;
 544
 545         source = policydb->type_val_to_struct[scontext->type - 1];
 546         BUG_ON(!source);
 547
 548         if (!source->bounds)
 549                 return;
 550
 551         target = policydb->type_val_to_struct[tcontext->type - 1];
 552         BUG_ON(!target);
 553
 554         memset(&lo_avd, 0, sizeof(lo_avd));
 555
 556         memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
 557         lo_scontext.type = source->bounds;
 558
 559         if (target->bounds) {
 560                 memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
 561                 lo_tcontext.type = target->bounds;
 562                 tcontextp = &lo_tcontext;
 563         }
 564
 565         context_struct_compute_av(policydb, &lo_scontext,
 566                                   tcontextp,
 567                                   tclass,
 568                                   &lo_avd,
 569                                   NULL);
 570
 571         masked = ~lo_avd.allowed & avd->allowed;
 572
 573         if (likely(!masked))
 574                 return;         /* no masked permission */
 575
 576         /* mask violated permissions */
 577         avd->allowed &= ~masked;
 578
 579         /* audit masked permissions */
 580         security_dump_masked_av(policydb, scontext, tcontext,
 581                                 tclass, masked, "bounds");
 582 }
 583
 584 /*
 585  * flag which drivers have permissions
 586  * only looking for ioctl based extended permissions
 587  */
 588 void services_compute_xperms_drivers(
 589                 struct extended_perms *xperms,
 590                 struct avtab_node *node)
 591 {
 592         unsigned int i;
 593
 594         if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 595                 /* if one or more driver has all permissions allowed */
 596                 for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++)
 597                         xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i];
 598         } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 599                 /* if allowing permissions within a driver */
 600                 security_xperm_set(xperms->drivers.p,
 601                                         node->datum.u.xperms->driver);
 602         }
 603
 604         xperms->len = 1;
 605 }
 606
 607 /*
 608  * Compute access vectors and extended permissions based on a context
 609  * structure pair for the permissions in a particular class.
 610  */
 611 static void context_struct_compute_av(struct policydb *policydb,
 612                                       struct context *scontext,
 613                                       struct context *tcontext,
 614                                       u16 tclass,
 615                                       struct av_decision *avd,
 616                                       struct extended_perms *xperms)
 617 {
 618         struct constraint_node *constraint;
 619         struct role_allow *ra;
 620         struct avtab_key avkey;
 621         struct avtab_node *node;
 622         struct class_datum *tclass_datum;
 623         struct ebitmap *sattr, *tattr;
 624         struct ebitmap_node *snode, *tnode;
 625         unsigned int i, j;
 626
 627         avd->allowed = 0;
 628         avd->auditallow = 0;
 629         avd->auditdeny = 0xffffffff;
 630         if (xperms) {
 631                 memset(&xperms->drivers, 0, sizeof(xperms->drivers));
 632                 xperms->len = 0;
 633         }
 634
 635         if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
 636                 if (printk_ratelimit())
 637                         pr_warn("SELinux:  Invalid class %hu\n", tclass);
 638                 return;
 639         }
 640
 641         tclass_datum = policydb->class_val_to_struct[tclass - 1];
 642
 643         /*
 644          * If a specific type enforcement rule was defined for
 645          * this permission check, then use it.
 646          */
 647         avkey.target_class = tclass;
 648         avkey.specified = AVTAB_AV | AVTAB_XPERMS;
 649         sattr = &policydb->type_attr_map_array[scontext->type - 1];
 650         tattr = &policydb->type_attr_map_array[tcontext->type - 1];
 651         ebitmap_for_each_positive_bit(sattr, snode, i) {
 652                 ebitmap_for_each_positive_bit(tattr, tnode, j) {
 653                         avkey.source_type = i + 1;
 654                         avkey.target_type = j + 1;
 655                         for (node = avtab_search_node(&policydb->te_avtab,
 656                                                       &avkey);
 657                              node;
 658                              node = avtab_search_node_next(node, avkey.specified)) {
 659                                 if (node->key.specified == AVTAB_ALLOWED)
 660                                         avd->allowed |= node->datum.u.data;
 661                                 else if (node->key.specified == AVTAB_AUDITALLOW)
 662                                         avd->auditallow |= node->datum.u.data;
 663                                 else if (node->key.specified == AVTAB_AUDITDENY)
 664                                         avd->auditdeny &= node->datum.u.data;
 665                                 else if (xperms && (node->key.specified & AVTAB_XPERMS))
 666                                         services_compute_xperms_drivers(xperms, node);
 667                         }
 668
 669                         /* Check conditional av table for additional permissions */
 670                         cond_compute_av(&policydb->te_cond_avtab, &avkey,
 671                                         avd, xperms);
 672
 673                 }
 674         }
 675
 676         /*
 677          * Remove any permissions prohibited by a constraint (this includes
 678          * the MLS policy).
 679          */
 680         constraint = tclass_datum->constraints;
 681         while (constraint) {
 682                 if ((constraint->permissions & (avd->allowed)) &&
 683                     !constraint_expr_eval(policydb, scontext, tcontext, NULL,
 684                                           constraint->expr)) {
 685                         avd->allowed &= ~(constraint->permissions);
 686                 }
 687                 constraint = constraint->next;
 688         }
 689
 690         /*
 691          * If checking process transition permission and the
 692          * role is changing, then check the (current_role, new_role)
 693          * pair.
 694          */
 695         if (tclass == policydb->process_class &&
 696             (avd->allowed & policydb->process_trans_perms) &&
 697             scontext->role != tcontext->role) {
 698                 for (ra = policydb->role_allow; ra; ra = ra->next) {
 699                         if (scontext->role == ra->role &&
 700                             tcontext->role == ra->new_role)
 701                                 break;
 702                 }
 703                 if (!ra)
 704                         avd->allowed &= ~policydb->process_trans_perms;
 705         }
 706
 707         /*
 708          * If the given source and target types have boundary
 709          * constraint, lazy checks have to mask any violated
 710          * permission and notice it to userspace via audit.
 711          */
 712         type_attribute_bounds_av(policydb, scontext, tcontext,
 713                                  tclass, avd);
 714 }
 715
 716 static int security_validtrans_handle_fail(struct selinux_policy *policy,
 717                                         struct sidtab_entry *oentry,
 718                                         struct sidtab_entry *nentry,
 719                                         struct sidtab_entry *tentry,
 720                                         u16 tclass)
 721 {
 722         struct policydb *p = &policy->policydb;
 723         struct sidtab *sidtab = policy->sidtab;
 724         char *o = NULL, *n = NULL, *t = NULL;
 725         u32 olen, nlen, tlen;
 726
 727         if (sidtab_entry_to_string(p, sidtab, oentry, &o, &olen))
 728                 goto out;
 729         if (sidtab_entry_to_string(p, sidtab, nentry, &n, &nlen))
 730                 goto out;
 731         if (sidtab_entry_to_string(p, sidtab, tentry, &t, &tlen))
 732                 goto out;
 733         audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
 734                   "op=security_validate_transition seresult=denied"
 735                   " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
 736                   o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
 737 out:
 738         kfree(o);
 739         kfree(n);
 740         kfree(t);
 741
 742         if (!enforcing_enabled())
 743                 return 0;
 744         return -EPERM;
 745 }
 746
 747 static int security_compute_validatetrans(u32 oldsid, u32 newsid, u32 tasksid,
 748                                           u16 orig_tclass, bool user)
 749 {
 750         struct selinux_policy *policy;
 751         struct policydb *policydb;
 752         struct sidtab *sidtab;
 753         struct sidtab_entry *oentry;
 754         struct sidtab_entry *nentry;
 755         struct sidtab_entry *tentry;
 756         struct class_datum *tclass_datum;
 757         struct constraint_node *constraint;
 758         u16 tclass;
 759         int rc = 0;
 760
 761
 762         if (!selinux_initialized())
 763                 return 0;
 764
 765         rcu_read_lock();
 766
 767         policy = rcu_dereference(selinux_state.policy);
 768         policydb = &policy->policydb;
 769         sidtab = policy->sidtab;
 770
 771         if (!user)
 772                 tclass = unmap_class(&policy->map, orig_tclass);
 773         else
 774                 tclass = orig_tclass;
 775
 776         if (!tclass || tclass > policydb->p_classes.nprim) {
 777                 rc = -EINVAL;
 778                 goto out;
 779         }
 780         tclass_datum = policydb->class_val_to_struct[tclass - 1];
 781
 782         oentry = sidtab_search_entry(sidtab, oldsid);
 783         if (!oentry) {
 784                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 785                         __func__, oldsid);
 786                 rc = -EINVAL;
 787                 goto out;
 788         }
 789
 790         nentry = sidtab_search_entry(sidtab, newsid);
 791         if (!nentry) {
 792                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 793                         __func__, newsid);
 794                 rc = -EINVAL;
 795                 goto out;
 796         }
 797
 798         tentry = sidtab_search_entry(sidtab, tasksid);
 799         if (!tentry) {
 800                 pr_err("SELinux: %s:  unrecognized SID %d\n",
 801                         __func__, tasksid);
 802                 rc = -EINVAL;
 803                 goto out;
 804         }
 805
 806         constraint = tclass_datum->validatetrans;
 807         while (constraint) {
 808                 if (!constraint_expr_eval(policydb, &oentry->context,
 809                                           &nentry->context, &tentry->context,
 810                                           constraint->expr)) {
 811                         if (user)
 812                                 rc = -EPERM;
 813                         else
 814                                 rc = security_validtrans_handle_fail(policy,
 815                                                                 oentry,
 816                                                                 nentry,
 817                                                                 tentry,
 818                                                                 tclass);
 819                         goto out;
 820                 }
 821                 constraint = constraint->next;
 822         }
 823
 824 out:
 825         rcu_read_unlock();
 826         return rc;
 827 }
 828
 829 int security_validate_transition_user(u32 oldsid, u32 newsid, u32 tasksid,
 830                                       u16 tclass)
 831 {
 832         return security_compute_validatetrans(oldsid, newsid, tasksid,
 833                                               tclass, true);
 834 }
 835
 836 int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
 837                                  u16 orig_tclass)
 838 {
 839         return security_compute_validatetrans(oldsid, newsid, tasksid,
 840                                               orig_tclass, false);
 841 }
 842
 843 /*
 844  * security_bounded_transition - check whether the given
 845  * transition is directed to bounded, or not.
 846  * It returns 0, if @newsid is bounded by @oldsid.
 847  * Otherwise, it returns error code.
 848  *
 849  * @oldsid : current security identifier
 850  * @newsid : destinated security identifier
 851  */
 852 int security_bounded_transition(u32 old_sid, u32 new_sid)
 853 {
 854         struct selinux_policy *policy;
 855         struct policydb *policydb;
 856         struct sidtab *sidtab;
 857         struct sidtab_entry *old_entry, *new_entry;
 858         struct type_datum *type;
 859         u32 index;
 860         int rc;
 861
 862         if (!selinux_initialized())
 863                 return 0;
 864
 865         rcu_read_lock();
 866         policy = rcu_dereference(selinux_state.policy);
 867         policydb = &policy->policydb;
 868         sidtab = policy->sidtab;
 869
 870         rc = -EINVAL;
 871         old_entry = sidtab_search_entry(sidtab, old_sid);
 872         if (!old_entry) {
 873                 pr_err("SELinux: %s: unrecognized SID %u\n",
 874                        __func__, old_sid);
 875                 goto out;
 876         }
 877
 878         rc = -EINVAL;
 879         new_entry = sidtab_search_entry(sidtab, new_sid);
 880         if (!new_entry) {
 881                 pr_err("SELinux: %s: unrecognized SID %u\n",
 882                        __func__, new_sid);
 883                 goto out;
 884         }
 885
 886         rc = 0;
 887         /* type/domain unchanged */
 888         if (old_entry->context.type == new_entry->context.type)
 889                 goto out;
 890
 891         index = new_entry->context.type;
 892         while (true) {
 893                 type = policydb->type_val_to_struct[index - 1];
 894                 BUG_ON(!type);
 895
 896                 /* not bounded anymore */
 897                 rc = -EPERM;
 898                 if (!type->bounds)
 899                         break;
 900
 901                 /* @newsid is bounded by @oldsid */
 902                 rc = 0;
 903                 if (type->bounds == old_entry->context.type)
 904                         break;
 905
 906                 index = type->bounds;
 907         }
 908
 909         if (rc) {
 910                 char *old_name = NULL;
 911                 char *new_name = NULL;
 912                 u32 length;
 913
 914                 if (!sidtab_entry_to_string(policydb, sidtab, old_entry,
 915                                             &old_name, &length) &&
 916                     !sidtab_entry_to_string(policydb, sidtab, new_entry,
 917                                             &new_name, &length)) {
 918                         audit_log(audit_context(),
 919                                   GFP_ATOMIC, AUDIT_SELINUX_ERR,
 920                                   "op=security_bounded_transition "
 921                                   "seresult=denied "
 922                                   "oldcontext=%s newcontext=%s",
 923                                   old_name, new_name);
 924                 }
 925                 kfree(new_name);
 926                 kfree(old_name);
 927         }
 928 out:
 929         rcu_read_unlock();
 930
 931         return rc;
 932 }
 933
 934 static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
 935 {
 936         avd->allowed = 0;
 937         avd->auditallow = 0;
 938         avd->auditdeny = 0xffffffff;
 939         if (policy)
 940                 avd->seqno = policy->latest_granting;
 941         else
 942                 avd->seqno = 0;
 943         avd->flags = 0;
 944 }
 945
 946 void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
 947                                         struct avtab_node *node)
 948 {
 949         unsigned int i;
 950
 951         if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 952                 if (xpermd->driver != node->datum.u.xperms->driver)
 953                         return;
 954         } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 955                 if (!security_xperm_test(node->datum.u.xperms->perms.p,
 956                                         xpermd->driver))
 957                         return;
 958         } else {
 959                 BUG();
 960         }
 961
 962         if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
 963                 xpermd->used |= XPERMS_ALLOWED;
 964                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 965                         memset(xpermd->allowed->p, 0xff,
 966                                         sizeof(xpermd->allowed->p));
 967                 }
 968                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 969                         for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
 970                                 xpermd->allowed->p[i] |=
 971                                         node->datum.u.xperms->perms.p[i];
 972                 }
 973         } else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
 974                 xpermd->used |= XPERMS_AUDITALLOW;
 975                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 976                         memset(xpermd->auditallow->p, 0xff,
 977                                         sizeof(xpermd->auditallow->p));
 978                 }
 979                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 980                         for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
 981                                 xpermd->auditallow->p[i] |=
 982                                         node->datum.u.xperms->perms.p[i];
 983                 }
 984         } else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
 985                 xpermd->used |= XPERMS_DONTAUDIT;
 986                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
 987                         memset(xpermd->dontaudit->p, 0xff,
 988                                         sizeof(xpermd->dontaudit->p));
 989                 }
 990                 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
 991                         for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
 992                                 xpermd->dontaudit->p[i] |=
 993                                         node->datum.u.xperms->perms.p[i];
 994                 }
 995         } else {
 996                 BUG();
 997         }
 998 }
 999
1000 void security_compute_xperms_decision(u32 ssid,
1001                                       u32 tsid,
1002                                       u16 orig_tclass,
1003                                       u8 driver,
1004                                       struct extended_perms_decision *xpermd)
1005 {
1006         struct selinux_policy *policy;
1007         struct policydb *policydb;
1008         struct sidtab *sidtab;
1009         u16 tclass;
1010         struct context *scontext, *tcontext;
1011         struct avtab_key avkey;
1012         struct avtab_node *node;
1013         struct ebitmap *sattr, *tattr;
1014         struct ebitmap_node *snode, *tnode;
1015         unsigned int i, j;
1016
1017         xpermd->driver = driver;
1018         xpermd->used = 0;
1019         memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
1020         memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
1021         memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
1022
1023         rcu_read_lock();
1024         if (!selinux_initialized())
1025                 goto allow;
1026
1027         policy = rcu_dereference(selinux_state.policy);
1028         policydb = &policy->policydb;
1029         sidtab = policy->sidtab;
1030
1031         scontext = sidtab_search(sidtab, ssid);
1032         if (!scontext) {
1033                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1034                        __func__, ssid);
1035                 goto out;
1036         }
1037
1038         tcontext = sidtab_search(sidtab, tsid);
1039         if (!tcontext) {
1040                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1041                        __func__, tsid);
1042                 goto out;
1043         }
1044
1045         tclass = unmap_class(&policy->map, orig_tclass);
1046         if (unlikely(orig_tclass && !tclass)) {
1047                 if (policydb->allow_unknown)
1048                         goto allow;
1049                 goto out;
1050         }
1051
1052
1053         if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
1054                 pr_warn_ratelimited("SELinux:  Invalid class %hu\n", tclass);
1055                 goto out;
1056         }
1057
1058         avkey.target_class = tclass;
1059         avkey.specified = AVTAB_XPERMS;
1060         sattr = &policydb->type_attr_map_array[scontext->type - 1];
1061         tattr = &policydb->type_attr_map_array[tcontext->type - 1];
1062         ebitmap_for_each_positive_bit(sattr, snode, i) {
1063                 ebitmap_for_each_positive_bit(tattr, tnode, j) {
1064                         avkey.source_type = i + 1;
1065                         avkey.target_type = j + 1;
1066                         for (node = avtab_search_node(&policydb->te_avtab,
1067                                                       &avkey);
1068                              node;
1069                              node = avtab_search_node_next(node, avkey.specified))
1070                                 services_compute_xperms_decision(xpermd, node);
1071
1072                         cond_compute_xperms(&policydb->te_cond_avtab,
1073                                                 &avkey, xpermd);
1074                 }
1075         }
1076 out:
1077         rcu_read_unlock();
1078         return;
1079 allow:
1080         memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
1081         goto out;
1082 }
1083
1084 /**
1085  * security_compute_av - Compute access vector decisions.
1086  * @ssid: source security identifier
1087  * @tsid: target security identifier
1088  * @orig_tclass: target security class
1089  * @avd: access vector decisions
1090  * @xperms: extended permissions
1091  *
1092  * Compute a set of access vector decisions based on the
1093  * SID pair (@ssid, @tsid) for the permissions in @tclass.
1094  */
1095 void security_compute_av(u32 ssid,
1096                          u32 tsid,
1097                          u16 orig_tclass,
1098                          struct av_decision *avd,
1099                          struct extended_perms *xperms)
1100 {
1101         struct selinux_policy *policy;
1102         struct policydb *policydb;
1103         struct sidtab *sidtab;
1104         u16 tclass;
1105         struct context *scontext = NULL, *tcontext = NULL;
1106
1107         rcu_read_lock();
1108         policy = rcu_dereference(selinux_state.policy);
1109         avd_init(policy, avd);
1110         xperms->len = 0;
1111         if (!selinux_initialized())
1112                 goto allow;
1113
1114         policydb = &policy->policydb;
1115         sidtab = policy->sidtab;
1116
1117         scontext = sidtab_search(sidtab, ssid);
1118         if (!scontext) {
1119                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1120                        __func__, ssid);
1121                 goto out;
1122         }
1123
1124         /* permissive domain? */
1125         if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1126                 avd->flags |= AVD_FLAGS_PERMISSIVE;
1127
1128         tcontext = sidtab_search(sidtab, tsid);
1129         if (!tcontext) {
1130                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1131                        __func__, tsid);
1132                 goto out;
1133         }
1134
1135         tclass = unmap_class(&policy->map, orig_tclass);
1136         if (unlikely(orig_tclass && !tclass)) {
1137                 if (policydb->allow_unknown)
1138                         goto allow;
1139                 goto out;
1140         }
1141         context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1142                                   xperms);
1143         map_decision(&policy->map, orig_tclass, avd,
1144                      policydb->allow_unknown);
1145 out:
1146         rcu_read_unlock();
1147         return;
1148 allow:
1149         avd->allowed = 0xffffffff;
1150         goto out;
1151 }
1152
1153 void security_compute_av_user(u32 ssid,
1154                               u32 tsid,
1155                               u16 tclass,
1156                               struct av_decision *avd)
1157 {
1158         struct selinux_policy *policy;
1159         struct policydb *policydb;
1160         struct sidtab *sidtab;
1161         struct context *scontext = NULL, *tcontext = NULL;
1162
1163         rcu_read_lock();
1164         policy = rcu_dereference(selinux_state.policy);
1165         avd_init(policy, avd);
1166         if (!selinux_initialized())
1167                 goto allow;
1168
1169         policydb = &policy->policydb;
1170         sidtab = policy->sidtab;
1171
1172         scontext = sidtab_search(sidtab, ssid);
1173         if (!scontext) {
1174                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1175                        __func__, ssid);
1176                 goto out;
1177         }
1178
1179         /* permissive domain? */
1180         if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1181                 avd->flags |= AVD_FLAGS_PERMISSIVE;
1182
1183         tcontext = sidtab_search(sidtab, tsid);
1184         if (!tcontext) {
1185                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1186                        __func__, tsid);
1187                 goto out;
1188         }
1189
1190         if (unlikely(!tclass)) {
1191                 if (policydb->allow_unknown)
1192                         goto allow;
1193                 goto out;
1194         }
1195
1196         context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1197                                   NULL);
1198  out:
1199         rcu_read_unlock();
1200         return;
1201 allow:
1202         avd->allowed = 0xffffffff;
1203         goto out;
1204 }
1205
1206 /*
1207  * Write the security context string representation of
1208  * the context structure `context' into a dynamically
1209  * allocated string of the correct size.  Set `*scontext'
1210  * to point to this string and set `*scontext_len' to
1211  * the length of the string.
1212  */
1213 static int context_struct_to_string(struct policydb *p,
1214                                     struct context *context,
1215                                     char **scontext, u32 *scontext_len)
1216 {
1217         char *scontextp;
1218
1219         if (scontext)
1220                 *scontext = NULL;
1221         *scontext_len = 0;
1222
1223         if (context->len) {
1224                 *scontext_len = context->len;
1225                 if (scontext) {
1226                         *scontext = kstrdup(context->str, GFP_ATOMIC);
1227                         if (!(*scontext))
1228                                 return -ENOMEM;
1229                 }
1230                 return 0;
1231         }
1232
1233         /* Compute the size of the context. */
1234         *scontext_len += strlen(sym_name(p, SYM_USERS, context->user - 1)) + 1;
1235         *scontext_len += strlen(sym_name(p, SYM_ROLES, context->role - 1)) + 1;
1236         *scontext_len += strlen(sym_name(p, SYM_TYPES, context->type - 1)) + 1;
1237         *scontext_len += mls_compute_context_len(p, context);
1238
1239         if (!scontext)
1240                 return 0;
1241
1242         /* Allocate space for the context; caller must free this space. */
1243         scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
1244         if (!scontextp)
1245                 return -ENOMEM;
1246         *scontext = scontextp;
1247
1248         /*
1249          * Copy the user name, role name and type name into the context.
1250          */
1251         scontextp += sprintf(scontextp, "%s:%s:%s",
1252                 sym_name(p, SYM_USERS, context->user - 1),
1253                 sym_name(p, SYM_ROLES, context->role - 1),
1254                 sym_name(p, SYM_TYPES, context->type - 1));
1255
1256         mls_sid_to_context(p, context, &scontextp);
1257
1258         *scontextp = 0;
1259
1260         return 0;
1261 }
1262
1263 static int sidtab_entry_to_string(struct policydb *p,
1264                                   struct sidtab *sidtab,
1265                                   struct sidtab_entry *entry,
1266                                   char **scontext, u32 *scontext_len)
1267 {
1268         int rc = sidtab_sid2str_get(sidtab, entry, scontext, scontext_len);
1269
1270         if (rc != -ENOENT)
1271                 return rc;
1272
1273         rc = context_struct_to_string(p, &entry->context, scontext,
1274                                       scontext_len);
1275         if (!rc && scontext)
1276                 sidtab_sid2str_put(sidtab, entry, *scontext, *scontext_len);
1277         return rc;
1278 }
1279
1280 #include "initial_sid_to_string.h"
1281
1282 int security_sidtab_hash_stats(char *page)
1283 {
1284         struct selinux_policy *policy;
1285         int rc;
1286
1287         if (!selinux_initialized()) {
1288                 pr_err("SELinux: %s:  called before initial load_policy\n",
1289                        __func__);
1290                 return -EINVAL;
1291         }
1292
1293         rcu_read_lock();
1294         policy = rcu_dereference(selinux_state.policy);
1295         rc = sidtab_hash_stats(policy->sidtab, page);
1296         rcu_read_unlock();
1297
1298         return rc;
1299 }
1300
1301 const char *security_get_initial_sid_context(u32 sid)
1302 {
1303         if (unlikely(sid > SECINITSID_NUM))
1304                 return NULL;
1305         return initial_sid_to_string[sid];
1306 }
1307
1308 static int security_sid_to_context_core(u32 sid, char **scontext,
1309                                         u32 *scontext_len, int force,
1310                                         int only_invalid)
1311 {
1312         struct selinux_policy *policy;
1313         struct policydb *policydb;
1314         struct sidtab *sidtab;
1315         struct sidtab_entry *entry;
1316         int rc = 0;
1317
1318         if (scontext)
1319                 *scontext = NULL;
1320         *scontext_len  = 0;
1321
1322         if (!selinux_initialized()) {
1323                 if (sid <= SECINITSID_NUM) {
1324                         char *scontextp;
1325                         const char *s = initial_sid_to_string[sid];
1326
1327                         if (!s)
1328                                 return -EINVAL;
1329                         *scontext_len = strlen(s) + 1;
1330                         if (!scontext)
1331                                 return 0;
1332                         scontextp = kmemdup(s, *scontext_len, GFP_ATOMIC);
1333                         if (!scontextp)
1334                                 return -ENOMEM;
1335                         *scontext = scontextp;
1336                         return 0;
1337                 }
1338                 pr_err("SELinux: %s:  called before initial "
1339                        "load_policy on unknown SID %d\n", __func__, sid);
1340                 return -EINVAL;
1341         }
1342         rcu_read_lock();
1343         policy = rcu_dereference(selinux_state.policy);
1344         policydb = &policy->policydb;
1345         sidtab = policy->sidtab;
1346
1347         if (force)
1348                 entry = sidtab_search_entry_force(sidtab, sid);
1349         else
1350                 entry = sidtab_search_entry(sidtab, sid);
1351         if (!entry) {
1352                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1353                         __func__, sid);
1354                 rc = -EINVAL;
1355                 goto out_unlock;
1356         }
1357         if (only_invalid && !entry->context.len)
1358                 goto out_unlock;
1359
1360         rc = sidtab_entry_to_string(policydb, sidtab, entry, scontext,
1361                                     scontext_len);
1362
1363 out_unlock:
1364         rcu_read_unlock();
1365         return rc;
1366
1367 }
1368
1369 /**
1370  * security_sid_to_context - Obtain a context for a given SID.
1371  * @sid: security identifier, SID
1372  * @scontext: security context
1373  * @scontext_len: length in bytes
1374  *
1375  * Write the string representation of the context associated with @sid
1376  * into a dynamically allocated string of the correct size.  Set @scontext
1377  * to point to this string and set @scontext_len to the length of the string.
1378  */
1379 int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
1380 {
1381         return security_sid_to_context_core(sid, scontext,
1382                                             scontext_len, 0, 0);
1383 }
1384
1385 int security_sid_to_context_force(u32 sid,
1386                                   char **scontext, u32 *scontext_len)
1387 {
1388         return security_sid_to_context_core(sid, scontext,
1389                                             scontext_len, 1, 0);
1390 }
1391
1392 /**
1393  * security_sid_to_context_inval - Obtain a context for a given SID if it
1394  *                                 is invalid.
1395  * @sid: security identifier, SID
1396  * @scontext: security context
1397  * @scontext_len: length in bytes
1398  *
1399  * Write the string representation of the context associated with @sid
1400  * into a dynamically allocated string of the correct size, but only if the
1401  * context is invalid in the current policy.  Set @scontext to point to
1402  * this string (or NULL if the context is valid) and set @scontext_len to
1403  * the length of the string (or 0 if the context is valid).
1404  */
1405 int security_sid_to_context_inval(u32 sid,
1406                                   char **scontext, u32 *scontext_len)
1407 {
1408         return security_sid_to_context_core(sid, scontext,
1409                                             scontext_len, 1, 1);
1410 }
1411
1412 /*
1413  * Caveat:  Mutates scontext.
1414  */
1415 static int string_to_context_struct(struct policydb *pol,
1416                                     struct sidtab *sidtabp,
1417                                     char *scontext,
1418                                     struct context *ctx,
1419                                     u32 def_sid)
1420 {
1421         struct role_datum *role;
1422         struct type_datum *typdatum;
1423         struct user_datum *usrdatum;
1424         char *scontextp, *p, oldc;
1425         int rc = 0;
1426
1427         context_init(ctx);
1428
1429         /* Parse the security context. */
1430
1431         rc = -EINVAL;
1432         scontextp = scontext;
1433
1434         /* Extract the user. */
1435         p = scontextp;
1436         while (*p && *p != ':')
1437                 p++;
1438
1439         if (*p == 0)
1440                 goto out;
1441
1442         *p++ = 0;
1443
1444         usrdatum = symtab_search(&pol->p_users, scontextp);
1445         if (!usrdatum)
1446                 goto out;
1447
1448         ctx->user = usrdatum->value;
1449
1450         /* Extract role. */
1451         scontextp = p;
1452         while (*p && *p != ':')
1453                 p++;
1454
1455         if (*p == 0)
1456                 goto out;
1457
1458         *p++ = 0;
1459
1460         role = symtab_search(&pol->p_roles, scontextp);
1461         if (!role)
1462                 goto out;
1463         ctx->role = role->value;
1464
1465         /* Extract type. */
1466         scontextp = p;
1467         while (*p && *p != ':')
1468                 p++;
1469         oldc = *p;
1470         *p++ = 0;
1471
1472         typdatum = symtab_search(&pol->p_types, scontextp);
1473         if (!typdatum || typdatum->attribute)
1474                 goto out;
1475
1476         ctx->type = typdatum->value;
1477
1478         rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
1479         if (rc)
1480                 goto out;
1481
1482         /* Check the validity of the new context. */
1483         rc = -EINVAL;
1484         if (!policydb_context_isvalid(pol, ctx))
1485                 goto out;
1486         rc = 0;
1487 out:
1488         if (rc)
1489                 context_destroy(ctx);
1490         return rc;
1491 }
1492
1493 static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
1494                                         u32 *sid, u32 def_sid, gfp_t gfp_flags,
1495                                         int force)
1496 {
1497         struct selinux_policy *policy;
1498         struct policydb *policydb;
1499         struct sidtab *sidtab;
1500         char *scontext2, *str = NULL;
1501         struct context context;
1502         int rc = 0;
1503
1504         /* An empty security context is never valid. */
1505         if (!scontext_len)
1506                 return -EINVAL;
1507
1508         /* Copy the string to allow changes and ensure a NUL terminator */
1509         scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
1510         if (!scontext2)
1511                 return -ENOMEM;
1512
1513         if (!selinux_initialized()) {
1514                 u32 i;
1515
1516                 for (i = 1; i < SECINITSID_NUM; i++) {
1517                         const char *s = initial_sid_to_string[i];
1518
1519                         if (s && !strcmp(s, scontext2)) {
1520                                 *sid = i;
1521                                 goto out;
1522                         }
1523                 }
1524                 *sid = SECINITSID_KERNEL;
1525                 goto out;
1526         }
1527         *sid = SECSID_NULL;
1528
1529         if (force) {
1530                 /* Save another copy for storing in uninterpreted form */
1531                 rc = -ENOMEM;
1532                 str = kstrdup(scontext2, gfp_flags);
1533                 if (!str)
1534                         goto out;
1535         }
1536 retry:
1537         rcu_read_lock();
1538         policy = rcu_dereference(selinux_state.policy);
1539         policydb = &policy->policydb;
1540         sidtab = policy->sidtab;
1541         rc = string_to_context_struct(policydb, sidtab, scontext2,
1542                                       &context, def_sid);
1543         if (rc == -EINVAL && force) {
1544                 context.str = str;
1545                 context.len = strlen(str) + 1;
1546                 str = NULL;
1547         } else if (rc)
1548                 goto out_unlock;
1549         rc = sidtab_context_to_sid(sidtab, &context, sid);
1550         if (rc == -ESTALE) {
1551                 rcu_read_unlock();
1552                 if (context.str) {
1553                         str = context.str;
1554                         context.str = NULL;
1555                 }
1556                 context_destroy(&context);
1557                 goto retry;
1558         }
1559         context_destroy(&context);
1560 out_unlock:
1561         rcu_read_unlock();
1562 out:
1563         kfree(scontext2);
1564         kfree(str);
1565         return rc;
1566 }
1567
1568 /**
1569  * security_context_to_sid - Obtain a SID for a given security context.
1570  * @scontext: security context
1571  * @scontext_len: length in bytes
1572  * @sid: security identifier, SID
1573  * @gfp: context for the allocation
1574  *
1575  * Obtains a SID associated with the security context that
1576  * has the string representation specified by @scontext.
1577  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1578  * memory is available, or 0 on success.
1579  */
1580 int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid,
1581                             gfp_t gfp)
1582 {
1583         return security_context_to_sid_core(scontext, scontext_len,
1584                                             sid, SECSID_NULL, gfp, 0);
1585 }
1586
1587 int security_context_str_to_sid(const char *scontext, u32 *sid, gfp_t gfp)
1588 {
1589         return security_context_to_sid(scontext, strlen(scontext),
1590                                        sid, gfp);
1591 }
1592
1593 /**
1594  * security_context_to_sid_default - Obtain a SID for a given security context,
1595  * falling back to specified default if needed.
1596  *
1597  * @scontext: security context
1598  * @scontext_len: length in bytes
1599  * @sid: security identifier, SID
1600  * @def_sid: default SID to assign on error
1601  * @gfp_flags: the allocator get-free-page (GFP) flags
1602  *
1603  * Obtains a SID associated with the security context that
1604  * has the string representation specified by @scontext.
1605  * The default SID is passed to the MLS layer to be used to allow
1606  * kernel labeling of the MLS field if the MLS field is not present
1607  * (for upgrading to MLS without full relabel).
1608  * Implicitly forces adding of the context even if it cannot be mapped yet.
1609  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1610  * memory is available, or 0 on success.
1611  */
1612 int security_context_to_sid_default(const char *scontext, u32 scontext_len,
1613                                     u32 *sid, u32 def_sid, gfp_t gfp_flags)
1614 {
1615         return security_context_to_sid_core(scontext, scontext_len,
1616                                             sid, def_sid, gfp_flags, 1);
1617 }
1618
1619 int security_context_to_sid_force(const char *scontext, u32 scontext_len,
1620                                   u32 *sid)
1621 {
1622         return security_context_to_sid_core(scontext, scontext_len,
1623                                             sid, SECSID_NULL, GFP_KERNEL, 1);
1624 }
1625
1626 static int compute_sid_handle_invalid_context(
1627         struct selinux_policy *policy,
1628         struct sidtab_entry *sentry,
1629         struct sidtab_entry *tentry,
1630         u16 tclass,
1631         struct context *newcontext)
1632 {
1633         struct policydb *policydb = &policy->policydb;
1634         struct sidtab *sidtab = policy->sidtab;
1635         char *s = NULL, *t = NULL, *n = NULL;
1636         u32 slen, tlen, nlen;
1637         struct audit_buffer *ab;
1638
1639         if (sidtab_entry_to_string(policydb, sidtab, sentry, &s, &slen))
1640                 goto out;
1641         if (sidtab_entry_to_string(policydb, sidtab, tentry, &t, &tlen))
1642                 goto out;
1643         if (context_struct_to_string(policydb, newcontext, &n, &nlen))
1644                 goto out;
1645         ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
1646         if (!ab)
1647                 goto out;
1648         audit_log_format(ab,
1649                          "op=security_compute_sid invalid_context=");
1650         /* no need to record the NUL with untrusted strings */
1651         audit_log_n_untrustedstring(ab, n, nlen - 1);
1652         audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
1653                          s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
1654         audit_log_end(ab);
1655 out:
1656         kfree(s);
1657         kfree(t);
1658         kfree(n);
1659         if (!enforcing_enabled())
1660                 return 0;
1661         return -EACCES;
1662 }
1663
1664 static void filename_compute_type(struct policydb *policydb,
1665                                   struct context *newcontext,
1666                                   u32 stype, u32 ttype, u16 tclass,
1667                                   const char *objname)
1668 {
1669         struct filename_trans_key ft;
1670         struct filename_trans_datum *datum;
1671
1672         /*
1673          * Most filename trans rules are going to live in specific directories
1674          * like /dev or /var/run.  This bitmap will quickly skip rule searches
1675          * if the ttype does not contain any rules.
1676          */
1677         if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
1678                 return;
1679
1680         ft.ttype = ttype;
1681         ft.tclass = tclass;
1682         ft.name = objname;
1683
1684         datum = policydb_filenametr_search(policydb, &ft);
1685         while (datum) {
1686                 if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
1687                         newcontext->type = datum->otype;
1688                         return;
1689                 }
1690                 datum = datum->next;
1691         }
1692 }
1693
1694 static int security_compute_sid(u32 ssid,
1695                                 u32 tsid,
1696                                 u16 orig_tclass,
1697                                 u16 specified,
1698                                 const char *objname,
1699                                 u32 *out_sid,
1700                                 bool kern)
1701 {
1702         struct selinux_policy *policy;
1703         struct policydb *policydb;
1704         struct sidtab *sidtab;
1705         struct class_datum *cladatum;
1706         struct context *scontext, *tcontext, newcontext;
1707         struct sidtab_entry *sentry, *tentry;
1708         struct avtab_key avkey;
1709         struct avtab_node *avnode, *node;
1710         u16 tclass;
1711         int rc = 0;
1712         bool sock;
1713
1714         if (!selinux_initialized()) {
1715                 switch (orig_tclass) {
1716                 case SECCLASS_PROCESS: /* kernel value */
1717                         *out_sid = ssid;
1718                         break;
1719                 default:
1720                         *out_sid = tsid;
1721                         break;
1722                 }
1723                 goto out;
1724         }
1725
1726 retry:
1727         cladatum = NULL;
1728         context_init(&newcontext);
1729
1730         rcu_read_lock();
1731
1732         policy = rcu_dereference(selinux_state.policy);
1733
1734         if (kern) {
1735                 tclass = unmap_class(&policy->map, orig_tclass);
1736                 sock = security_is_socket_class(orig_tclass);
1737         } else {
1738                 tclass = orig_tclass;
1739                 sock = security_is_socket_class(map_class(&policy->map,
1740                                                           tclass));
1741         }
1742
1743         policydb = &policy->policydb;
1744         sidtab = policy->sidtab;
1745
1746         sentry = sidtab_search_entry(sidtab, ssid);
1747         if (!sentry) {
1748                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1749                        __func__, ssid);
1750                 rc = -EINVAL;
1751                 goto out_unlock;
1752         }
1753         tentry = sidtab_search_entry(sidtab, tsid);
1754         if (!tentry) {
1755                 pr_err("SELinux: %s:  unrecognized SID %d\n",
1756                        __func__, tsid);
1757                 rc = -EINVAL;
1758                 goto out_unlock;
1759         }
1760
1761         scontext = &sentry->context;
1762         tcontext = &tentry->context;
1763
1764         if (tclass && tclass <= policydb->p_classes.nprim)
1765                 cladatum = policydb->class_val_to_struct[tclass - 1];
1766
1767         /* Set the user identity. */
1768         switch (specified) {
1769         case AVTAB_TRANSITION:
1770         case AVTAB_CHANGE:
1771                 if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1772                         newcontext.user = tcontext->user;
1773                 } else {
1774                         /* notice this gets both DEFAULT_SOURCE and unset */
1775                         /* Use the process user identity. */
1776                         newcontext.user = scontext->user;
1777                 }
1778                 break;
1779         case AVTAB_MEMBER:
1780                 /* Use the related object owner. */
1781                 newcontext.user = tcontext->user;
1782                 break;
1783         }
1784
1785         /* Set the role to default values. */
1786         if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1787                 newcontext.role = scontext->role;
1788         } else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1789                 newcontext.role = tcontext->role;
1790         } else {
1791                 if ((tclass == policydb->process_class) || sock)
1792                         newcontext.role = scontext->role;
1793                 else
1794                         newcontext.role = OBJECT_R_VAL;
1795         }
1796
1797         /* Set the type to default values. */
1798         if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1799                 newcontext.type = scontext->type;
1800         } else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1801                 newcontext.type = tcontext->type;
1802         } else {
1803                 if ((tclass == policydb->process_class) || sock) {
1804                         /* Use the type of process. */
1805                         newcontext.type = scontext->type;
1806                 } else {
1807                         /* Use the type of the related object. */
1808                         newcontext.type = tcontext->type;
1809                 }
1810         }
1811
1812         /* Look for a type transition/member/change rule. */
1813         avkey.source_type = scontext->type;
1814         avkey.target_type = tcontext->type;
1815         avkey.target_class = tclass;
1816         avkey.specified = specified;
1817         avnode = avtab_search_node(&policydb->te_avtab, &avkey);
1818
1819         /* If no permanent rule, also check for enabled conditional rules */
1820         if (!avnode) {
1821                 node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1822                 for (; node; node = avtab_search_node_next(node, specified)) {
1823                         if (node->key.specified & AVTAB_ENABLED) {
1824                                 avnode = node;
1825                                 break;
1826                         }
1827                 }
1828         }
1829
1830         if (avnode) {
1831                 /* Use the type from the type transition/member/change rule. */
1832                 newcontext.type = avnode->datum.u.data;
1833         }
1834
1835         /* if we have a objname this is a file trans check so check those rules */
1836         if (objname)
1837                 filename_compute_type(policydb, &newcontext, scontext->type,
1838                                       tcontext->type, tclass, objname);
1839
1840         /* Check for class-specific changes. */
1841         if (specified & AVTAB_TRANSITION) {
1842                 /* Look for a role transition rule. */
1843                 struct role_trans_datum *rtd;
1844                 struct role_trans_key rtk = {
1845                         .role = scontext->role,
1846                         .type = tcontext->type,
1847                         .tclass = tclass,
1848                 };
1849
1850                 rtd = policydb_roletr_search(policydb, &rtk);
1851                 if (rtd)
1852                         newcontext.role = rtd->new_role;
1853         }
1854
1855         /* Set the MLS attributes.
1856            This is done last because it may allocate memory. */
1857         rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1858                              &newcontext, sock);
1859         if (rc)
1860                 goto out_unlock;
1861
1862         /* Check the validity of the context. */
1863         if (!policydb_context_isvalid(policydb, &newcontext)) {
1864                 rc = compute_sid_handle_invalid_context(policy, sentry,
1865                                                         tentry, tclass,
1866                                                         &newcontext);
1867                 if (rc)
1868                         goto out_unlock;
1869         }
1870         /* Obtain the sid for the context. */
1871         rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1872         if (rc == -ESTALE) {
1873                 rcu_read_unlock();
1874                 context_destroy(&newcontext);
1875                 goto retry;
1876         }
1877 out_unlock:
1878         rcu_read_unlock();
1879         context_destroy(&newcontext);
1880 out:
1881         return rc;
1882 }
1883
1884 /**
1885  * security_transition_sid - Compute the SID for a new subject/object.
1886  * @ssid: source security identifier
1887  * @tsid: target security identifier
1888  * @tclass: target security class
1889  * @qstr: object name
1890  * @out_sid: security identifier for new subject/object
1891  *
1892  * Compute a SID to use for labeling a new subject or object in the
1893  * class @tclass based on a SID pair (@ssid, @tsid).
1894  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1895  * if insufficient memory is available, or %0 if the new SID was
1896  * computed successfully.
1897  */
1898 int security_transition_sid(u32 ssid, u32 tsid, u16 tclass,
1899                             const struct qstr *qstr, u32 *out_sid)
1900 {
1901         return security_compute_sid(ssid, tsid, tclass,
1902                                     AVTAB_TRANSITION,
1903                                     qstr ? qstr->name : NULL, out_sid, true);
1904 }
1905
1906 int security_transition_sid_user(u32 ssid, u32 tsid, u16 tclass,
1907                                  const char *objname, u32 *out_sid)
1908 {
1909         return security_compute_sid(ssid, tsid, tclass,
1910                                     AVTAB_TRANSITION,
1911                                     objname, out_sid, false);
1912 }
1913
1914 /**
1915  * security_member_sid - Compute the SID for member selection.
1916  * @ssid: source security identifier
1917  * @tsid: target security identifier
1918  * @tclass: target security class
1919  * @out_sid: security identifier for selected member
1920  *
1921  * Compute a SID to use when selecting a member of a polyinstantiated
1922  * object of class @tclass based on a SID pair (@ssid, @tsid).
1923  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1924  * if insufficient memory is available, or %0 if the SID was
1925  * computed successfully.
1926  */
1927 int security_member_sid(u32 ssid,
1928                         u32 tsid,
1929                         u16 tclass,
1930                         u32 *out_sid)
1931 {
1932         return security_compute_sid(ssid, tsid, tclass,
1933                                     AVTAB_MEMBER, NULL,
1934                                     out_sid, false);
1935 }
1936
1937 /**
1938  * security_change_sid - Compute the SID for object relabeling.
1939  * @ssid: source security identifier
1940  * @tsid: target security identifier
1941  * @tclass: target security class
1942  * @out_sid: security identifier for selected member
1943  *
1944  * Compute a SID to use for relabeling an object of class @tclass
1945  * based on a SID pair (@ssid, @tsid).
1946  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1947  * if insufficient memory is available, or %0 if the SID was
1948  * computed successfully.
1949  */
1950 int security_change_sid(u32 ssid,
1951                         u32 tsid,
1952                         u16 tclass,
1953                         u32 *out_sid)
1954 {
1955         return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, NULL,
1956                                     out_sid, false);
1957 }
1958
1959 static inline int convert_context_handle_invalid_context(
1960         struct policydb *policydb,
1961         struct context *context)
1962 {
1963         char *s;
1964         u32 len;
1965
1966         if (enforcing_enabled())
1967                 return -EINVAL;
1968
1969         if (!context_struct_to_string(policydb, context, &s, &len)) {
1970                 pr_warn("SELinux:  Context %s would be invalid if enforcing\n",
1971                         s);
1972                 kfree(s);
1973         }
1974         return 0;
1975 }
1976
1977 /**
1978  * services_convert_context - Convert a security context across policies.
1979  * @args: populated convert_context_args struct
1980  * @oldc: original context
1981  * @newc: converted context
1982  * @gfp_flags: allocation flags
1983  *
1984  * Convert the values in the security context structure @oldc from the values
1985  * specified in the policy @args->oldp to the values specified in the policy
1986  * @args->newp, storing the new context in @newc, and verifying that the
1987  * context is valid under the new policy.
1988  */
1989 int services_convert_context(struct convert_context_args *args,
1990                              struct context *oldc, struct context *newc,
1991                              gfp_t gfp_flags)
1992 {
1993         struct ocontext *oc;
1994         struct role_datum *role;
1995         struct type_datum *typdatum;
1996         struct user_datum *usrdatum;
1997         char *s;
1998         u32 len;
1999         int rc;
2000
2001         if (oldc->str) {
2002                 s = kstrdup(oldc->str, gfp_flags);
2003                 if (!s)
2004                         return -ENOMEM;
2005
2006                 rc = string_to_context_struct(args->newp, NULL, s, newc, SECSID_NULL);
2007                 if (rc == -EINVAL) {
2008                         /*
2009                          * Retain string representation for later mapping.
2010                          *
2011                          * IMPORTANT: We need to copy the contents of oldc->str
2012                          * back into s again because string_to_context_struct()
2013                          * may have garbled it.
2014                          */
2015                         memcpy(s, oldc->str, oldc->len);
2016                         context_init(newc);
2017                         newc->str = s;
2018                         newc->len = oldc->len;
2019                         return 0;
2020                 }
2021                 kfree(s);
2022                 if (rc) {
2023                         /* Other error condition, e.g. ENOMEM. */
2024                         pr_err("SELinux:   Unable to map context %s, rc = %d.\n",
2025                                oldc->str, -rc);
2026                         return rc;
2027                 }
2028                 pr_info("SELinux:  Context %s became valid (mapped).\n",
2029                         oldc->str);
2030                 return 0;
2031         }
2032
2033         context_init(newc);
2034
2035         /* Convert the user. */
2036         usrdatum = symtab_search(&args->newp->p_users,
2037                                  sym_name(args->oldp, SYM_USERS, oldc->user - 1));
2038         if (!usrdatum)
2039                 goto bad;
2040         newc->user = usrdatum->value;
2041
2042         /* Convert the role. */
2043         role = symtab_search(&args->newp->p_roles,
2044                              sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2045         if (!role)
2046                 goto bad;
2047         newc->role = role->value;
2048
2049         /* Convert the type. */
2050         typdatum = symtab_search(&args->newp->p_types,
2051                                  sym_name(args->oldp, SYM_TYPES, oldc->type - 1));
2052         if (!typdatum)
2053                 goto bad;
2054         newc->type = typdatum->value;
2055
2056         /* Convert the MLS fields if dealing with MLS policies */
2057         if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2058                 rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2059                 if (rc)
2060                         goto bad;
2061         } else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2062                 /*
2063                  * Switching between non-MLS and MLS policy:
2064                  * ensure that the MLS fields of the context for all
2065                  * existing entries in the sidtab are filled in with a
2066                  * suitable default value, likely taken from one of the
2067                  * initial SIDs.
2068                  */
2069                 oc = args->newp->ocontexts[OCON_ISID];
2070                 while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2071                         oc = oc->next;
2072                 if (!oc) {
2073                         pr_err("SELinux:  unable to look up"
2074                                 " the initial SIDs list\n");
2075                         goto bad;
2076                 }
2077                 rc = mls_range_set(newc, &oc->context[0].range);
2078                 if (rc)
2079                         goto bad;
2080         }
2081
2082         /* Check the validity of the new context. */
2083         if (!policydb_context_isvalid(args->newp, newc)) {
2084                 rc = convert_context_handle_invalid_context(args->oldp, oldc);
2085                 if (rc)
2086                         goto bad;
2087         }
2088
2089         return 0;
2090 bad:
2091         /* Map old representation to string and save it. */
2092         rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2093         if (rc)
2094                 return rc;
2095         context_destroy(newc);
2096         newc->str = s;
2097         newc->len = len;
2098         pr_info("SELinux:  Context %s became invalid (unmapped).\n",
2099                 newc->str);
2100         return 0;
2101 }
2102
2103 static void security_load_policycaps(struct selinux_policy *policy)
2104 {
2105         struct policydb *p;
2106         unsigned int i;
2107         struct ebitmap_node *node;
2108
2109         p = &policy->policydb;
2110
2111         for (i = 0; i < ARRAY_SIZE(selinux_state.policycap); i++)
2112                 WRITE_ONCE(selinux_state.policycap[i],
2113                         ebitmap_get_bit(&p->policycaps, i));
2114
2115         for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2116                 pr_info("SELinux:  policy capability %s=%d\n",
2117                         selinux_policycap_names[i],
2118                         ebitmap_get_bit(&p->policycaps, i));
2119
2120         ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2121                 if (i >= ARRAY_SIZE(selinux_policycap_names))
2122                         pr_info("SELinux:  unknown policy capability %u\n",
2123                                 i);
2124         }
2125 }
2126
2127 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2128                                 struct selinux_policy *newpolicy);
2129
2130 static void selinux_policy_free(struct selinux_policy *policy)
2131 {
2132         if (!policy)
2133                 return;
2134
2135         sidtab_destroy(policy->sidtab);
2136         kfree(policy->map.mapping);
2137         policydb_destroy(&policy->policydb);
2138         kfree(policy->sidtab);
2139         kfree(policy);
2140 }
2141
2142 static void selinux_policy_cond_free(struct selinux_policy *policy)
2143 {
2144         cond_policydb_destroy_dup(&policy->policydb);
2145         kfree(policy);
2146 }
2147
2148 void selinux_policy_cancel(struct selinux_load_state *load_state)
2149 {
2150         struct selinux_state *state = &selinux_state;
2151         struct selinux_policy *oldpolicy;
2152
2153         oldpolicy = rcu_dereference_protected(state->policy,
2154                                         lockdep_is_held(&state->policy_mutex));
2155
2156         sidtab_cancel_convert(oldpolicy->sidtab);
2157         selinux_policy_free(load_state->policy);
2158         kfree(load_state->convert_data);
2159 }
2160
2161 static void selinux_notify_policy_change(u32 seqno)
2162 {
2163         /* Flush external caches and notify userspace of policy load */
2164         avc_ss_reset(seqno);
2165         selnl_notify_policyload(seqno);
2166         selinux_status_update_policyload(seqno);
2167         selinux_netlbl_cache_invalidate();
2168         selinux_xfrm_notify_policyload();
2169         selinux_ima_measure_state_locked();
2170 }
2171
2172 void selinux_policy_commit(struct selinux_load_state *load_state)
2173 {
2174         struct selinux_state *state = &selinux_state;
2175         struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2176         unsigned long flags;
2177         u32 seqno;
2178
2179         oldpolicy = rcu_dereference_protected(state->policy,
2180                                         lockdep_is_held(&state->policy_mutex));
2181
2182         /* If switching between different policy types, log MLS status */
2183         if (oldpolicy) {
2184                 if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2185                         pr_info("SELinux: Disabling MLS support...\n");
2186                 else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2187                         pr_info("SELinux: Enabling MLS support...\n");
2188         }
2189
2190         /* Set latest granting seqno for new policy. */
2191         if (oldpolicy)
2192                 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2193         else
2194                 newpolicy->latest_granting = 1;
2195         seqno = newpolicy->latest_granting;
2196
2197         /* Install the new policy. */
2198         if (oldpolicy) {
2199                 sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2200                 rcu_assign_pointer(state->policy, newpolicy);
2201                 sidtab_freeze_end(oldpolicy->sidtab, &flags);
2202         } else {
2203                 rcu_assign_pointer(state->policy, newpolicy);
2204         }
2205
2206         /* Load the policycaps from the new policy */
2207         security_load_policycaps(newpolicy);
2208
2209         if (!selinux_initialized()) {
2210                 /*
2211                  * After first policy load, the security server is
2212                  * marked as initialized and ready to handle requests and
2213                  * any objects created prior to policy load are then labeled.
2214                  */
2215                 selinux_mark_initialized();
2216                 selinux_complete_init();
2217         }
2218
2219         /* Free the old policy */
2220         synchronize_rcu();
2221         selinux_policy_free(oldpolicy);
2222         kfree(load_state->convert_data);
2223
2224         /* Notify others of the policy change */
2225         selinux_notify_policy_change(seqno);
2226 }
2227
2228 /**
2229  * security_load_policy - Load a security policy configuration.
2230  * @data: binary policy data
2231  * @len: length of data in bytes
2232  * @load_state: policy load state
2233  *
2234  * Load a new set of security policy configuration data,
2235  * validate it and convert the SID table as necessary.
2236  * This function will flush the access vector cache after
2237  * loading the new policy.
2238  */
2239 int security_load_policy(void *data, size_t len,
2240                          struct selinux_load_state *load_state)
2241 {
2242         struct selinux_state *state = &selinux_state;
2243         struct selinux_policy *newpolicy, *oldpolicy;
2244         struct selinux_policy_convert_data *convert_data;
2245         int rc = 0;
2246         struct policy_file file = { data, len }, *fp = &file;
2247
2248         newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2249         if (!newpolicy)
2250                 return -ENOMEM;
2251
2252         newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2253         if (!newpolicy->sidtab) {
2254                 rc = -ENOMEM;
2255                 goto err_policy;
2256         }
2257
2258         rc = policydb_read(&newpolicy->policydb, fp);
2259         if (rc)
2260                 goto err_sidtab;
2261
2262         newpolicy->policydb.len = len;
2263         rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2264                                 &newpolicy->map);
2265         if (rc)
2266                 goto err_policydb;
2267
2268         rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2269         if (rc) {
2270                 pr_err("SELinux:  unable to load the initial SIDs\n");
2271                 goto err_mapping;
2272         }
2273
2274         if (!selinux_initialized()) {
2275                 /* First policy load, so no need to preserve state from old policy */
2276                 load_state->policy = newpolicy;
2277                 load_state->convert_data = NULL;
2278                 return 0;
2279         }
2280
2281         oldpolicy = rcu_dereference_protected(state->policy,
2282                                         lockdep_is_held(&state->policy_mutex));
2283
2284         /* Preserve active boolean values from the old policy */
2285         rc = security_preserve_bools(oldpolicy, newpolicy);
2286         if (rc) {
2287                 pr_err("SELinux:  unable to preserve booleans\n");
2288                 goto err_free_isids;
2289         }
2290
2291         /*
2292          * Convert the internal representations of contexts
2293          * in the new SID table.
2294          */
2295
2296         convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2297         if (!convert_data) {
2298                 rc = -ENOMEM;
2299                 goto err_free_isids;
2300         }
2301
2302         convert_data->args.oldp = &oldpolicy->policydb;
2303         convert_data->args.newp = &newpolicy->policydb;
2304
2305         convert_data->sidtab_params.args = &convert_data->args;
2306         convert_data->sidtab_params.target = newpolicy->sidtab;
2307
2308         rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2309         if (rc) {
2310                 pr_err("SELinux:  unable to convert the internal"
2311                         " representation of contexts in the new SID"
2312                         " table\n");
2313                 goto err_free_convert_data;
2314         }
2315
2316         load_state->policy = newpolicy;
2317         load_state->convert_data = convert_data;
2318         return 0;
2319
2320 err_free_convert_data:
2321         kfree(convert_data);
2322 err_free_isids:
2323         sidtab_destroy(newpolicy->sidtab);
2324 err_mapping:
2325         kfree(newpolicy->map.mapping);
2326 err_policydb:
2327         policydb_destroy(&newpolicy->policydb);
2328 err_sidtab:
2329         kfree(newpolicy->sidtab);
2330 err_policy:
2331         kfree(newpolicy);
2332
2333         return rc;
2334 }
2335
2336 /**
2337  * ocontext_to_sid - Helper to safely get sid for an ocontext
2338  * @sidtab: SID table
2339  * @c: ocontext structure
2340  * @index: index of the context entry (0 or 1)
2341  * @out_sid: pointer to the resulting SID value
2342  *
2343  * For all ocontexts except OCON_ISID the SID fields are populated
2344  * on-demand when needed. Since updating the SID value is an SMP-sensitive
2345  * operation, this helper must be used to do that safely.
2346  *
2347  * WARNING: This function may return -ESTALE, indicating that the caller
2348  * must retry the operation after re-acquiring the policy pointer!
2349  */
2350 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2351                            size_t index, u32 *out_sid)
2352 {
2353         int rc;
2354         u32 sid;
2355
2356         /* Ensure the associated sidtab entry is visible to this thread. */
2357         sid = smp_load_acquire(&c->sid[index]);
2358         if (!sid) {
2359                 rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2360                 if (rc)
2361                         return rc;
2362
2363                 /*
2364                  * Ensure the new sidtab entry is visible to other threads
2365                  * when they see the SID.
2366                  */
2367                 smp_store_release(&c->sid[index], sid);
2368         }
2369         *out_sid = sid;
2370         return 0;
2371 }
2372
2373 /**
2374  * security_port_sid - Obtain the SID for a port.
2375  * @protocol: protocol number
2376  * @port: port number
2377  * @out_sid: security identifier
2378  */
2379 int security_port_sid(u8 protocol, u16 port, u32 *out_sid)
2380 {
2381         struct selinux_policy *policy;
2382         struct policydb *policydb;
2383         struct sidtab *sidtab;
2384         struct ocontext *c;
2385         int rc;
2386
2387         if (!selinux_initialized()) {
2388                 *out_sid = SECINITSID_PORT;
2389                 return 0;
2390         }
2391
2392 retry:
2393         rc = 0;
2394         rcu_read_lock();
2395         policy = rcu_dereference(selinux_state.policy);
2396         policydb = &policy->policydb;
2397         sidtab = policy->sidtab;
2398
2399         c = policydb->ocontexts[OCON_PORT];
2400         while (c) {
2401                 if (c->u.port.protocol == protocol &&
2402                     c->u.port.low_port <= port &&
2403                     c->u.port.high_port >= port)
2404                         break;
2405                 c = c->next;
2406         }
2407
2408         if (c) {
2409                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2410                 if (rc == -ESTALE) {
2411                         rcu_read_unlock();
2412                         goto retry;
2413                 }
2414                 if (rc)
2415                         goto out;
2416         } else {
2417                 *out_sid = SECINITSID_PORT;
2418         }
2419
2420 out:
2421         rcu_read_unlock();
2422         return rc;
2423 }
2424
2425 /**
2426  * security_ib_pkey_sid - Obtain the SID for a pkey.
2427  * @subnet_prefix: Subnet Prefix
2428  * @pkey_num: pkey number
2429  * @out_sid: security identifier
2430  */
2431 int security_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2432 {
2433         struct selinux_policy *policy;
2434         struct policydb *policydb;
2435         struct sidtab *sidtab;
2436         struct ocontext *c;
2437         int rc;
2438
2439         if (!selinux_initialized()) {
2440                 *out_sid = SECINITSID_UNLABELED;
2441                 return 0;
2442         }
2443
2444 retry:
2445         rc = 0;
2446         rcu_read_lock();
2447         policy = rcu_dereference(selinux_state.policy);
2448         policydb = &policy->policydb;
2449         sidtab = policy->sidtab;
2450
2451         c = policydb->ocontexts[OCON_IBPKEY];
2452         while (c) {
2453                 if (c->u.ibpkey.low_pkey <= pkey_num &&
2454                     c->u.ibpkey.high_pkey >= pkey_num &&
2455                     c->u.ibpkey.subnet_prefix == subnet_prefix)
2456                         break;
2457
2458                 c = c->next;
2459         }
2460
2461         if (c) {
2462                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2463                 if (rc == -ESTALE) {
2464                         rcu_read_unlock();
2465                         goto retry;
2466                 }
2467                 if (rc)
2468                         goto out;
2469         } else
2470                 *out_sid = SECINITSID_UNLABELED;
2471
2472 out:
2473         rcu_read_unlock();
2474         return rc;
2475 }
2476
2477 /**
2478  * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2479  * @dev_name: device name
2480  * @port_num: port number
2481  * @out_sid: security identifier
2482  */
2483 int security_ib_endport_sid(const char *dev_name, u8 port_num, u32 *out_sid)
2484 {
2485         struct selinux_policy *policy;
2486         struct policydb *policydb;
2487         struct sidtab *sidtab;
2488         struct ocontext *c;
2489         int rc;
2490
2491         if (!selinux_initialized()) {
2492                 *out_sid = SECINITSID_UNLABELED;
2493                 return 0;
2494         }
2495
2496 retry:
2497         rc = 0;
2498         rcu_read_lock();
2499         policy = rcu_dereference(selinux_state.policy);
2500         policydb = &policy->policydb;
2501         sidtab = policy->sidtab;
2502
2503         c = policydb->ocontexts[OCON_IBENDPORT];
2504         while (c) {
2505                 if (c->u.ibendport.port == port_num &&
2506                     !strncmp(c->u.ibendport.dev_name,
2507                              dev_name,
2508                              IB_DEVICE_NAME_MAX))
2509                         break;
2510
2511                 c = c->next;
2512         }
2513
2514         if (c) {
2515                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2516                 if (rc == -ESTALE) {
2517                         rcu_read_unlock();
2518                         goto retry;
2519                 }
2520                 if (rc)
2521                         goto out;
2522         } else
2523                 *out_sid = SECINITSID_UNLABELED;
2524
2525 out:
2526         rcu_read_unlock();
2527         return rc;
2528 }
2529
2530 /**
2531  * security_netif_sid - Obtain the SID for a network interface.
2532  * @name: interface name
2533  * @if_sid: interface SID
2534  */
2535 int security_netif_sid(char *name, u32 *if_sid)
2536 {
2537         struct selinux_policy *policy;
2538         struct policydb *policydb;
2539         struct sidtab *sidtab;
2540         int rc;
2541         struct ocontext *c;
2542
2543         if (!selinux_initialized()) {
2544                 *if_sid = SECINITSID_NETIF;
2545                 return 0;
2546         }
2547
2548 retry:
2549         rc = 0;
2550         rcu_read_lock();
2551         policy = rcu_dereference(selinux_state.policy);
2552         policydb = &policy->policydb;
2553         sidtab = policy->sidtab;
2554
2555         c = policydb->ocontexts[OCON_NETIF];
2556         while (c) {
2557                 if (strcmp(name, c->u.name) == 0)
2558                         break;
2559                 c = c->next;
2560         }
2561
2562         if (c) {
2563                 rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2564                 if (rc == -ESTALE) {
2565                         rcu_read_unlock();
2566                         goto retry;
2567                 }
2568                 if (rc)
2569                         goto out;
2570         } else
2571                 *if_sid = SECINITSID_NETIF;
2572
2573 out:
2574         rcu_read_unlock();
2575         return rc;
2576 }
2577
2578 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2579 {
2580         int i, fail = 0;
2581
2582         for (i = 0; i < 4; i++)
2583                 if (addr[i] != (input[i] & mask[i])) {
2584                         fail = 1;
2585                         break;
2586                 }
2587
2588         return !fail;
2589 }
2590
2591 /**
2592  * security_node_sid - Obtain the SID for a node (host).
2593  * @domain: communication domain aka address family
2594  * @addrp: address
2595  * @addrlen: address length in bytes
2596  * @out_sid: security identifier
2597  */
2598 int security_node_sid(u16 domain,
2599                       void *addrp,
2600                       u32 addrlen,
2601                       u32 *out_sid)
2602 {
2603         struct selinux_policy *policy;
2604         struct policydb *policydb;
2605         struct sidtab *sidtab;
2606         int rc;
2607         struct ocontext *c;
2608
2609         if (!selinux_initialized()) {
2610                 *out_sid = SECINITSID_NODE;
2611                 return 0;
2612         }
2613
2614 retry:
2615         rcu_read_lock();
2616         policy = rcu_dereference(selinux_state.policy);
2617         policydb = &policy->policydb;
2618         sidtab = policy->sidtab;
2619
2620         switch (domain) {
2621         case AF_INET: {
2622                 u32 addr;
2623
2624                 rc = -EINVAL;
2625                 if (addrlen != sizeof(u32))
2626                         goto out;
2627
2628                 addr = *((u32 *)addrp);
2629
2630                 c = policydb->ocontexts[OCON_NODE];
2631                 while (c) {
2632                         if (c->u.node.addr == (addr & c->u.node.mask))
2633                                 break;
2634                         c = c->next;
2635                 }
2636                 break;
2637         }
2638
2639         case AF_INET6:
2640                 rc = -EINVAL;
2641                 if (addrlen != sizeof(u64) * 2)
2642                         goto out;
2643                 c = policydb->ocontexts[OCON_NODE6];
2644                 while (c) {
2645                         if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2646                                                 c->u.node6.mask))
2647                                 break;
2648                         c = c->next;
2649                 }
2650                 break;
2651
2652         default:
2653                 rc = 0;
2654                 *out_sid = SECINITSID_NODE;
2655                 goto out;
2656         }
2657
2658         if (c) {
2659                 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2660                 if (rc == -ESTALE) {
2661                         rcu_read_unlock();
2662                         goto retry;
2663                 }
2664                 if (rc)
2665                         goto out;
2666         } else {
2667                 *out_sid = SECINITSID_NODE;
2668         }
2669
2670         rc = 0;
2671 out:
2672         rcu_read_unlock();
2673         return rc;
2674 }
2675
2676 #define SIDS_NEL 25
2677
2678 /**
2679  * security_get_user_sids - Obtain reachable SIDs for a user.
2680  * @fromsid: starting SID
2681  * @username: username
2682  * @sids: array of reachable SIDs for user
2683  * @nel: number of elements in @sids
2684  *
2685  * Generate the set of SIDs for legal security contexts
2686  * for a given user that can be reached by @fromsid.
2687  * Set *@sids to point to a dynamically allocated
2688  * array containing the set of SIDs.  Set *@nel to the
2689  * number of elements in the array.
2690  */
2691
2692 int security_get_user_sids(u32 fromsid,
2693                            char *username,
2694                            u32 **sids,
2695                            u32 *nel)
2696 {
2697         struct selinux_policy *policy;
2698         struct policydb *policydb;
2699         struct sidtab *sidtab;
2700         struct context *fromcon, usercon;
2701         u32 *mysids = NULL, *mysids2, sid;
2702         u32 i, j, mynel, maxnel = SIDS_NEL;
2703         struct user_datum *user;
2704         struct role_datum *role;
2705         struct ebitmap_node *rnode, *tnode;
2706         int rc;
2707
2708         *sids = NULL;
2709         *nel = 0;
2710
2711         if (!selinux_initialized())
2712                 return 0;
2713
2714         mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2715         if (!mysids)
2716                 return -ENOMEM;
2717
2718 retry:
2719         mynel = 0;
2720         rcu_read_lock();
2721         policy = rcu_dereference(selinux_state.policy);
2722         policydb = &policy->policydb;
2723         sidtab = policy->sidtab;
2724
2725         context_init(&usercon);
2726
2727         rc = -EINVAL;
2728         fromcon = sidtab_search(sidtab, fromsid);
2729         if (!fromcon)
2730                 goto out_unlock;
2731
2732         rc = -EINVAL;
2733         user = symtab_search(&policydb->p_users, username);
2734         if (!user)
2735                 goto out_unlock;
2736
2737         usercon.user = user->value;
2738
2739         ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2740                 role = policydb->role_val_to_struct[i];
2741                 usercon.role = i + 1;
2742                 ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2743                         usercon.type = j + 1;
2744
2745                         if (mls_setup_user_range(policydb, fromcon, user,
2746                                                  &usercon))
2747                                 continue;
2748
2749                         rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2750                         if (rc == -ESTALE) {
2751                                 rcu_read_unlock();
2752                                 goto retry;
2753                         }
2754                         if (rc)
2755                                 goto out_unlock;
2756                         if (mynel < maxnel) {
2757                                 mysids[mynel++] = sid;
2758                         } else {
2759                                 rc = -ENOMEM;
2760                                 maxnel += SIDS_NEL;
2761                                 mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2762                                 if (!mysids2)
2763                                         goto out_unlock;
2764                                 memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2765                                 kfree(mysids);
2766                                 mysids = mysids2;
2767                                 mysids[mynel++] = sid;
2768                         }
2769                 }
2770         }
2771         rc = 0;
2772 out_unlock:
2773         rcu_read_unlock();
2774         if (rc || !mynel) {
2775                 kfree(mysids);
2776                 return rc;
2777         }
2778
2779         rc = -ENOMEM;
2780         mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2781         if (!mysids2) {
2782                 kfree(mysids);
2783                 return rc;
2784         }
2785         for (i = 0, j = 0; i < mynel; i++) {
2786                 struct av_decision dummy_avd;
2787                 rc = avc_has_perm_noaudit(fromsid, mysids[i],
2788                                           SECCLASS_PROCESS, /* kernel value */
2789                                           PROCESS__TRANSITION, AVC_STRICT,
2790                                           &dummy_avd);
2791                 if (!rc)
2792                         mysids2[j++] = mysids[i];
2793                 cond_resched();
2794         }
2795         kfree(mysids);
2796         *sids = mysids2;
2797         *nel = j;
2798         return 0;
2799 }
2800
2801 /**
2802  * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2803  * @policy: policy
2804  * @fstype: filesystem type
2805  * @path: path from root of mount
2806  * @orig_sclass: file security class
2807  * @sid: SID for path
2808  *
2809  * Obtain a SID to use for a file in a filesystem that
2810  * cannot support xattr or use a fixed labeling behavior like
2811  * transition SIDs or task SIDs.
2812  *
2813  * WARNING: This function may return -ESTALE, indicating that the caller
2814  * must retry the operation after re-acquiring the policy pointer!
2815  */
2816 static inline int __security_genfs_sid(struct selinux_policy *policy,
2817                                        const char *fstype,
2818                                        const char *path,
2819                                        u16 orig_sclass,
2820                                        u32 *sid)
2821 {
2822         struct policydb *policydb = &policy->policydb;
2823         struct sidtab *sidtab = policy->sidtab;
2824         u16 sclass;
2825         struct genfs *genfs;
2826         struct ocontext *c;
2827         int cmp = 0;
2828
2829         while (path[0] == '/' && path[1] == '/')
2830                 path++;
2831
2832         sclass = unmap_class(&policy->map, orig_sclass);
2833         *sid = SECINITSID_UNLABELED;
2834
2835         for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2836                 cmp = strcmp(fstype, genfs->fstype);
2837                 if (cmp <= 0)
2838                         break;
2839         }
2840
2841         if (!genfs || cmp)
2842                 return -ENOENT;
2843
2844         for (c = genfs->head; c; c = c->next) {
2845                 size_t len = strlen(c->u.name);
2846                 if ((!c->v.sclass || sclass == c->v.sclass) &&
2847                     (strncmp(c->u.name, path, len) == 0))
2848                         break;
2849         }
2850
2851         if (!c)
2852                 return -ENOENT;
2853
2854         return ocontext_to_sid(sidtab, c, 0, sid);
2855 }
2856
2857 /**
2858  * security_genfs_sid - Obtain a SID for a file in a filesystem
2859  * @fstype: filesystem type
2860  * @path: path from root of mount
2861  * @orig_sclass: file security class
2862  * @sid: SID for path
2863  *
2864  * Acquire policy_rwlock before calling __security_genfs_sid() and release
2865  * it afterward.
2866  */
2867 int security_genfs_sid(const char *fstype,
2868                        const char *path,
2869                        u16 orig_sclass,
2870                        u32 *sid)
2871 {
2872         struct selinux_policy *policy;
2873         int retval;
2874
2875         if (!selinux_initialized()) {
2876                 *sid = SECINITSID_UNLABELED;
2877                 return 0;
2878         }
2879
2880         do {
2881                 rcu_read_lock();
2882                 policy = rcu_dereference(selinux_state.policy);
2883                 retval = __security_genfs_sid(policy, fstype, path,
2884                                               orig_sclass, sid);
2885                 rcu_read_unlock();
2886         } while (retval == -ESTALE);
2887         return retval;
2888 }
2889
2890 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2891                         const char *fstype,
2892                         const char *path,
2893                         u16 orig_sclass,
2894                         u32 *sid)
2895 {
2896         /* no lock required, policy is not yet accessible by other threads */
2897         return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2898 }
2899
2900 /**
2901  * security_fs_use - Determine how to handle labeling for a filesystem.
2902  * @sb: superblock in question
2903  */
2904 int security_fs_use(struct super_block *sb)
2905 {
2906         struct selinux_policy *policy;
2907         struct policydb *policydb;
2908         struct sidtab *sidtab;
2909         int rc;
2910         struct ocontext *c;
2911         struct superblock_security_struct *sbsec = selinux_superblock(sb);
2912         const char *fstype = sb->s_type->name;
2913
2914         if (!selinux_initialized()) {
2915                 sbsec->behavior = SECURITY_FS_USE_NONE;
2916                 sbsec->sid = SECINITSID_UNLABELED;
2917                 return 0;
2918         }
2919
2920 retry:
2921         rcu_read_lock();
2922         policy = rcu_dereference(selinux_state.policy);
2923         policydb = &policy->policydb;
2924         sidtab = policy->sidtab;
2925
2926         c = policydb->ocontexts[OCON_FSUSE];
2927         while (c) {
2928                 if (strcmp(fstype, c->u.name) == 0)
2929                         break;
2930                 c = c->next;
2931         }
2932
2933         if (c) {
2934                 sbsec->behavior = c->v.behavior;
2935                 rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
2936                 if (rc == -ESTALE) {
2937                         rcu_read_unlock();
2938                         goto retry;
2939                 }
2940                 if (rc)
2941                         goto out;
2942         } else {
2943                 rc = __security_genfs_sid(policy, fstype, "/",
2944                                         SECCLASS_DIR, &sbsec->sid);
2945                 if (rc == -ESTALE) {
2946                         rcu_read_unlock();
2947                         goto retry;
2948                 }
2949                 if (rc) {
2950                         sbsec->behavior = SECURITY_FS_USE_NONE;
2951                         rc = 0;
2952                 } else {
2953                         sbsec->behavior = SECURITY_FS_USE_GENFS;
2954                 }
2955         }
2956
2957 out:
2958         rcu_read_unlock();
2959         return rc;
2960 }
2961
2962 int security_get_bools(struct selinux_policy *policy,
2963                        u32 *len, char ***names, int **values)
2964 {
2965         struct policydb *policydb;
2966         u32 i;
2967         int rc;
2968
2969         policydb = &policy->policydb;
2970
2971         *names = NULL;
2972         *values = NULL;
2973
2974         rc = 0;
2975         *len = policydb->p_bools.nprim;
2976         if (!*len)
2977                 goto out;
2978
2979         rc = -ENOMEM;
2980         *names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
2981         if (!*names)
2982                 goto err;
2983
2984         rc = -ENOMEM;
2985         *values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
2986         if (!*values)
2987                 goto err;
2988
2989         for (i = 0; i < *len; i++) {
2990                 (*values)[i] = policydb->bool_val_to_struct[i]->state;
2991
2992                 rc = -ENOMEM;
2993                 (*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
2994                                       GFP_ATOMIC);
2995                 if (!(*names)[i])
2996                         goto err;
2997         }
2998         rc = 0;
2999 out:
3000         return rc;
3001 err:
3002         if (*names) {
3003                 for (i = 0; i < *len; i++)
3004                         kfree((*names)[i]);
3005                 kfree(*names);
3006         }
3007         kfree(*values);
3008         *len = 0;
3009         *names = NULL;
3010         *values = NULL;
3011         goto out;
3012 }
3013
3014
3015 int security_set_bools(u32 len, int *values)
3016 {
3017         struct selinux_state *state = &selinux_state;
3018         struct selinux_policy *newpolicy, *oldpolicy;
3019         int rc;
3020         u32 i, seqno = 0;
3021
3022         if (!selinux_initialized())
3023                 return -EINVAL;
3024
3025         oldpolicy = rcu_dereference_protected(state->policy,
3026                                         lockdep_is_held(&state->policy_mutex));
3027
3028         /* Consistency check on number of booleans, should never fail */
3029         if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3030                 return -EINVAL;
3031
3032         newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3033         if (!newpolicy)
3034                 return -ENOMEM;
3035
3036         /*
3037          * Deep copy only the parts of the policydb that might be
3038          * modified as a result of changing booleans.
3039          */
3040         rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3041         if (rc) {
3042                 kfree(newpolicy);
3043                 return -ENOMEM;
3044         }
3045
3046         /* Update the boolean states in the copy */
3047         for (i = 0; i < len; i++) {
3048                 int new_state = !!values[i];
3049                 int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3050
3051                 if (new_state != old_state) {
3052                         audit_log(audit_context(), GFP_ATOMIC,
3053                                 AUDIT_MAC_CONFIG_CHANGE,
3054                                 "bool=%s val=%d old_val=%d auid=%u ses=%u",
3055                                 sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3056                                 new_state,
3057                                 old_state,
3058                                 from_kuid(&init_user_ns, audit_get_loginuid(current)),
3059                                 audit_get_sessionid(current));
3060                         newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3061                 }
3062         }
3063
3064         /* Re-evaluate the conditional rules in the copy */
3065         evaluate_cond_nodes(&newpolicy->policydb);
3066
3067         /* Set latest granting seqno for new policy */
3068         newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3069         seqno = newpolicy->latest_granting;
3070
3071         /* Install the new policy */
3072         rcu_assign_pointer(state->policy, newpolicy);
3073
3074         /*
3075          * Free the conditional portions of the old policydb
3076          * that were copied for the new policy, and the oldpolicy
3077          * structure itself but not what it references.
3078          */
3079         synchronize_rcu();
3080         selinux_policy_cond_free(oldpolicy);
3081
3082         /* Notify others of the policy change */
3083         selinux_notify_policy_change(seqno);
3084         return 0;
3085 }
3086
3087 int security_get_bool_value(u32 index)
3088 {
3089         struct selinux_policy *policy;
3090         struct policydb *policydb;
3091         int rc;
3092         u32 len;
3093
3094         if (!selinux_initialized())
3095                 return 0;
3096
3097         rcu_read_lock();
3098         policy = rcu_dereference(selinux_state.policy);
3099         policydb = &policy->policydb;
3100
3101         rc = -EFAULT;
3102         len = policydb->p_bools.nprim;
3103         if (index >= len)
3104                 goto out;
3105
3106         rc = policydb->bool_val_to_struct[index]->state;
3107 out:
3108         rcu_read_unlock();
3109         return rc;
3110 }
3111
3112 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3113                                 struct selinux_policy *newpolicy)
3114 {
3115         int rc, *bvalues = NULL;
3116         char **bnames = NULL;
3117         struct cond_bool_datum *booldatum;
3118         u32 i, nbools = 0;
3119
3120         rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3121         if (rc)
3122                 goto out;
3123         for (i = 0; i < nbools; i++) {
3124                 booldatum = symtab_search(&newpolicy->policydb.p_bools,
3125                                         bnames[i]);
3126                 if (booldatum)
3127                         booldatum->state = bvalues[i];
3128         }
3129         evaluate_cond_nodes(&newpolicy->policydb);
3130
3131 out:
3132         if (bnames) {
3133                 for (i = 0; i < nbools; i++)
3134                         kfree(bnames[i]);
3135         }
3136         kfree(bnames);
3137         kfree(bvalues);
3138         return rc;
3139 }
3140
3141 /*
3142  * security_sid_mls_copy() - computes a new sid based on the given
3143  * sid and the mls portion of mls_sid.
3144  */
3145 int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
3146 {
3147         struct selinux_policy *policy;
3148         struct policydb *policydb;
3149         struct sidtab *sidtab;
3150         struct context *context1;
3151         struct context *context2;
3152         struct context newcon;
3153         char *s;
3154         u32 len;
3155         int rc;
3156
3157         if (!selinux_initialized()) {
3158                 *new_sid = sid;
3159                 return 0;
3160         }
3161
3162 retry:
3163         rc = 0;
3164         context_init(&newcon);
3165
3166         rcu_read_lock();
3167         policy = rcu_dereference(selinux_state.policy);
3168         policydb = &policy->policydb;
3169         sidtab = policy->sidtab;
3170
3171         if (!policydb->mls_enabled) {
3172                 *new_sid = sid;
3173                 goto out_unlock;
3174         }
3175
3176         rc = -EINVAL;
3177         context1 = sidtab_search(sidtab, sid);
3178         if (!context1) {
3179                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3180                         __func__, sid);
3181                 goto out_unlock;
3182         }
3183
3184         rc = -EINVAL;
3185         context2 = sidtab_search(sidtab, mls_sid);
3186         if (!context2) {
3187                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3188                         __func__, mls_sid);
3189                 goto out_unlock;
3190         }
3191
3192         newcon.user = context1->user;
3193         newcon.role = context1->role;
3194         newcon.type = context1->type;
3195         rc = mls_context_cpy(&newcon, context2);
3196         if (rc)
3197                 goto out_unlock;
3198
3199         /* Check the validity of the new context. */
3200         if (!policydb_context_isvalid(policydb, &newcon)) {
3201                 rc = convert_context_handle_invalid_context(policydb,
3202                                                         &newcon);
3203                 if (rc) {
3204                         if (!context_struct_to_string(policydb, &newcon, &s,
3205                                                       &len)) {
3206                                 struct audit_buffer *ab;
3207
3208                                 ab = audit_log_start(audit_context(),
3209                                                      GFP_ATOMIC,
3210                                                      AUDIT_SELINUX_ERR);
3211                                 audit_log_format(ab,
3212                                                  "op=security_sid_mls_copy invalid_context=");
3213                                 /* don't record NUL with untrusted strings */
3214                                 audit_log_n_untrustedstring(ab, s, len - 1);
3215                                 audit_log_end(ab);
3216                                 kfree(s);
3217                         }
3218                         goto out_unlock;
3219                 }
3220         }
3221         rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3222         if (rc == -ESTALE) {
3223                 rcu_read_unlock();
3224                 context_destroy(&newcon);
3225                 goto retry;
3226         }
3227 out_unlock:
3228         rcu_read_unlock();
3229         context_destroy(&newcon);
3230         return rc;
3231 }
3232
3233 /**
3234  * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3235  * @nlbl_sid: NetLabel SID
3236  * @nlbl_type: NetLabel labeling protocol type
3237  * @xfrm_sid: XFRM SID
3238  * @peer_sid: network peer sid
3239  *
3240  * Description:
3241  * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3242  * resolved into a single SID it is returned via @peer_sid and the function
3243  * returns zero.  Otherwise @peer_sid is set to SECSID_NULL and the function
3244  * returns a negative value.  A table summarizing the behavior is below:
3245  *
3246  *                                 | function return |      @sid
3247  *   ------------------------------+-----------------+-----------------
3248  *   no peer labels                |        0        |    SECSID_NULL
3249  *   single peer label             |        0        |    <peer_label>
3250  *   multiple, consistent labels   |        0        |    <peer_label>
3251  *   multiple, inconsistent labels |    -<errno>     |    SECSID_NULL
3252  *
3253  */
3254 int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
3255                                  u32 xfrm_sid,
3256                                  u32 *peer_sid)
3257 {
3258         struct selinux_policy *policy;
3259         struct policydb *policydb;
3260         struct sidtab *sidtab;
3261         int rc;
3262         struct context *nlbl_ctx;
3263         struct context *xfrm_ctx;
3264
3265         *peer_sid = SECSID_NULL;
3266
3267         /* handle the common (which also happens to be the set of easy) cases
3268          * right away, these two if statements catch everything involving a
3269          * single or absent peer SID/label */
3270         if (xfrm_sid == SECSID_NULL) {
3271                 *peer_sid = nlbl_sid;
3272                 return 0;
3273         }
3274         /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3275          * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3276          * is present */
3277         if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3278                 *peer_sid = xfrm_sid;
3279                 return 0;
3280         }
3281
3282         if (!selinux_initialized())
3283                 return 0;
3284
3285         rcu_read_lock();
3286         policy = rcu_dereference(selinux_state.policy);
3287         policydb = &policy->policydb;
3288         sidtab = policy->sidtab;
3289
3290         /*
3291          * We don't need to check initialized here since the only way both
3292          * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3293          * security server was initialized and state->initialized was true.
3294          */
3295         if (!policydb->mls_enabled) {
3296                 rc = 0;
3297                 goto out;
3298         }
3299
3300         rc = -EINVAL;
3301         nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3302         if (!nlbl_ctx) {
3303                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3304                        __func__, nlbl_sid);
3305                 goto out;
3306         }
3307         rc = -EINVAL;
3308         xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3309         if (!xfrm_ctx) {
3310                 pr_err("SELinux: %s:  unrecognized SID %d\n",
3311                        __func__, xfrm_sid);
3312                 goto out;
3313         }
3314         rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3315         if (rc)
3316                 goto out;
3317
3318         /* at present NetLabel SIDs/labels really only carry MLS
3319          * information so if the MLS portion of the NetLabel SID
3320          * matches the MLS portion of the labeled XFRM SID/label
3321          * then pass along the XFRM SID as it is the most
3322          * expressive */
3323         *peer_sid = xfrm_sid;
3324 out:
3325         rcu_read_unlock();
3326         return rc;
3327 }
3328
3329 static int get_classes_callback(void *k, void *d, void *args)
3330 {
3331         struct class_datum *datum = d;
3332         char *name = k, **classes = args;
3333         u32 value = datum->value - 1;
3334
3335         classes[value] = kstrdup(name, GFP_ATOMIC);
3336         if (!classes[value])
3337                 return -ENOMEM;
3338
3339         return 0;
3340 }
3341
3342 int security_get_classes(struct selinux_policy *policy,
3343                          char ***classes, u32 *nclasses)
3344 {
3345         struct policydb *policydb;
3346         int rc;
3347
3348         policydb = &policy->policydb;
3349
3350         rc = -ENOMEM;
3351         *nclasses = policydb->p_classes.nprim;
3352         *classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3353         if (!*classes)
3354                 goto out;
3355
3356         rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3357                          *classes);
3358         if (rc) {
3359                 u32 i;
3360
3361                 for (i = 0; i < *nclasses; i++)
3362                         kfree((*classes)[i]);
3363                 kfree(*classes);
3364         }
3365
3366 out:
3367         return rc;
3368 }
3369
3370 static int get_permissions_callback(void *k, void *d, void *args)
3371 {
3372         struct perm_datum *datum = d;
3373         char *name = k, **perms = args;
3374         u32 value = datum->value - 1;
3375
3376         perms[value] = kstrdup(name, GFP_ATOMIC);
3377         if (!perms[value])
3378                 return -ENOMEM;
3379
3380         return 0;
3381 }
3382
3383 int security_get_permissions(struct selinux_policy *policy,
3384                              const char *class, char ***perms, u32 *nperms)
3385 {
3386         struct policydb *policydb;
3387         u32 i;
3388         int rc;
3389         struct class_datum *match;
3390
3391         policydb = &policy->policydb;
3392
3393         rc = -EINVAL;
3394         match = symtab_search(&policydb->p_classes, class);
3395         if (!match) {
3396                 pr_err("SELinux: %s:  unrecognized class %s\n",
3397                         __func__, class);
3398                 goto out;
3399         }
3400
3401         rc = -ENOMEM;
3402         *nperms = match->permissions.nprim;
3403         *perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3404         if (!*perms)
3405                 goto out;
3406
3407         if (match->comdatum) {
3408                 rc = hashtab_map(&match->comdatum->permissions.table,
3409                                  get_permissions_callback, *perms);
3410                 if (rc)
3411                         goto err;
3412         }
3413
3414         rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3415                          *perms);
3416         if (rc)
3417                 goto err;
3418
3419 out:
3420         return rc;
3421
3422 err:
3423         for (i = 0; i < *nperms; i++)
3424                 kfree((*perms)[i]);
3425         kfree(*perms);
3426         return rc;
3427 }
3428
3429 int security_get_reject_unknown(void)
3430 {
3431         struct selinux_policy *policy;
3432         int value;
3433
3434         if (!selinux_initialized())
3435                 return 0;
3436
3437         rcu_read_lock();
3438         policy = rcu_dereference(selinux_state.policy);
3439         value = policy->policydb.reject_unknown;
3440         rcu_read_unlock();
3441         return value;
3442 }
3443
3444 int security_get_allow_unknown(void)
3445 {
3446         struct selinux_policy *policy;
3447         int value;
3448
3449         if (!selinux_initialized())
3450                 return 0;
3451
3452         rcu_read_lock();
3453         policy = rcu_dereference(selinux_state.policy);
3454         value = policy->policydb.allow_unknown;
3455         rcu_read_unlock();
3456         return value;
3457 }
3458
3459 /**
3460  * security_policycap_supported - Check for a specific policy capability
3461  * @req_cap: capability
3462  *
3463  * Description:
3464  * This function queries the currently loaded policy to see if it supports the
3465  * capability specified by @req_cap.  Returns true (1) if the capability is
3466  * supported, false (0) if it isn't supported.
3467  *
3468  */
3469 int security_policycap_supported(unsigned int req_cap)
3470 {
3471         struct selinux_policy *policy;
3472         int rc;
3473
3474         if (!selinux_initialized())
3475                 return 0;
3476
3477         rcu_read_lock();
3478         policy = rcu_dereference(selinux_state.policy);
3479         rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3480         rcu_read_unlock();
3481
3482         return rc;
3483 }
3484
3485 struct selinux_audit_rule {
3486         u32 au_seqno;
3487         struct context au_ctxt;
3488 };
3489
3490 void selinux_audit_rule_free(void *vrule)
3491 {
3492         struct selinux_audit_rule *rule = vrule;
3493
3494         if (rule) {
3495                 context_destroy(&rule->au_ctxt);
3496                 kfree(rule);
3497         }
3498 }
3499
3500 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3501 {
3502         struct selinux_state *state = &selinux_state;
3503         struct selinux_policy *policy;
3504         struct policydb *policydb;
3505         struct selinux_audit_rule *tmprule;
3506         struct role_datum *roledatum;
3507         struct type_datum *typedatum;
3508         struct user_datum *userdatum;
3509         struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3510         int rc = 0;
3511
3512         *rule = NULL;
3513
3514         if (!selinux_initialized())
3515                 return -EOPNOTSUPP;
3516
3517         switch (field) {
3518         case AUDIT_SUBJ_USER:
3519         case AUDIT_SUBJ_ROLE:
3520         case AUDIT_SUBJ_TYPE:
3521         case AUDIT_OBJ_USER:
3522         case AUDIT_OBJ_ROLE:
3523         case AUDIT_OBJ_TYPE:
3524                 /* only 'equals' and 'not equals' fit user, role, and type */
3525                 if (op != Audit_equal && op != Audit_not_equal)
3526                         return -EINVAL;
3527                 break;
3528         case AUDIT_SUBJ_SEN:
3529         case AUDIT_SUBJ_CLR:
3530         case AUDIT_OBJ_LEV_LOW:
3531         case AUDIT_OBJ_LEV_HIGH:
3532                 /* we do not allow a range, indicated by the presence of '-' */
3533                 if (strchr(rulestr, '-'))
3534                         return -EINVAL;
3535                 break;
3536         default:
3537                 /* only the above fields are valid */
3538                 return -EINVAL;
3539         }
3540
3541         tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3542         if (!tmprule)
3543                 return -ENOMEM;
3544         context_init(&tmprule->au_ctxt);
3545
3546         rcu_read_lock();
3547         policy = rcu_dereference(state->policy);
3548         policydb = &policy->policydb;
3549         tmprule->au_seqno = policy->latest_granting;
3550         switch (field) {
3551         case AUDIT_SUBJ_USER:
3552         case AUDIT_OBJ_USER:
3553                 userdatum = symtab_search(&policydb->p_users, rulestr);
3554                 if (!userdatum) {
3555                         rc = -EINVAL;
3556                         goto err;
3557                 }
3558                 tmprule->au_ctxt.user = userdatum->value;
3559                 break;
3560         case AUDIT_SUBJ_ROLE:
3561         case AUDIT_OBJ_ROLE:
3562                 roledatum = symtab_search(&policydb->p_roles, rulestr);
3563                 if (!roledatum) {
3564                         rc = -EINVAL;
3565                         goto err;
3566                 }
3567                 tmprule->au_ctxt.role = roledatum->value;
3568                 break;
3569         case AUDIT_SUBJ_TYPE:
3570         case AUDIT_OBJ_TYPE:
3571                 typedatum = symtab_search(&policydb->p_types, rulestr);
3572                 if (!typedatum) {
3573                         rc = -EINVAL;
3574                         goto err;
3575                 }
3576                 tmprule->au_ctxt.type = typedatum->value;
3577                 break;
3578         case AUDIT_SUBJ_SEN:
3579         case AUDIT_SUBJ_CLR:
3580         case AUDIT_OBJ_LEV_LOW:
3581         case AUDIT_OBJ_LEV_HIGH:
3582                 rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3583                                      GFP_ATOMIC);
3584                 if (rc)
3585                         goto err;
3586                 break;
3587         }
3588         rcu_read_unlock();
3589
3590         *rule = tmprule;
3591         return 0;
3592
3593 err:
3594         rcu_read_unlock();
3595         selinux_audit_rule_free(tmprule);
3596         *rule = NULL;
3597         return rc;
3598 }
3599
3600 /* Check to see if the rule contains any selinux fields */
3601 int selinux_audit_rule_known(struct audit_krule *rule)
3602 {
3603         u32 i;
3604
3605         for (i = 0; i < rule->field_count; i++) {
3606                 struct audit_field *f = &rule->fields[i];
3607                 switch (f->type) {
3608                 case AUDIT_SUBJ_USER:
3609                 case AUDIT_SUBJ_ROLE:
3610                 case AUDIT_SUBJ_TYPE:
3611                 case AUDIT_SUBJ_SEN:
3612                 case AUDIT_SUBJ_CLR:
3613                 case AUDIT_OBJ_USER:
3614                 case AUDIT_OBJ_ROLE:
3615                 case AUDIT_OBJ_TYPE:
3616                 case AUDIT_OBJ_LEV_LOW:
3617                 case AUDIT_OBJ_LEV_HIGH:
3618                         return 1;
3619                 }
3620         }
3621
3622         return 0;
3623 }
3624
3625 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3626 {
3627         struct selinux_state *state = &selinux_state;
3628         struct selinux_policy *policy;
3629         struct context *ctxt;
3630         struct mls_level *level;
3631         struct selinux_audit_rule *rule = vrule;
3632         int match = 0;
3633
3634         if (unlikely(!rule)) {
3635                 WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3636                 return -ENOENT;
3637         }
3638
3639         if (!selinux_initialized())
3640                 return 0;
3641
3642         rcu_read_lock();
3643
3644         policy = rcu_dereference(state->policy);
3645
3646         if (rule->au_seqno < policy->latest_granting) {
3647                 match = -ESTALE;
3648                 goto out;
3649         }
3650
3651         ctxt = sidtab_search(policy->sidtab, sid);
3652         if (unlikely(!ctxt)) {
3653                 WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3654                           sid);
3655                 match = -ENOENT;
3656                 goto out;
3657         }
3658
3659         /* a field/op pair that is not caught here will simply fall through
3660            without a match */
3661         switch (field) {
3662         case AUDIT_SUBJ_USER:
3663         case AUDIT_OBJ_USER:
3664                 switch (op) {
3665                 case Audit_equal:
3666                         match = (ctxt->user == rule->au_ctxt.user);
3667                         break;
3668                 case Audit_not_equal:
3669                         match = (ctxt->user != rule->au_ctxt.user);
3670                         break;
3671                 }
3672                 break;
3673         case AUDIT_SUBJ_ROLE:
3674         case AUDIT_OBJ_ROLE:
3675                 switch (op) {
3676                 case Audit_equal:
3677                         match = (ctxt->role == rule->au_ctxt.role);
3678                         break;
3679                 case Audit_not_equal:
3680                         match = (ctxt->role != rule->au_ctxt.role);
3681                         break;
3682                 }
3683                 break;
3684         case AUDIT_SUBJ_TYPE:
3685         case AUDIT_OBJ_TYPE:
3686                 switch (op) {
3687                 case Audit_equal:
3688                         match = (ctxt->type == rule->au_ctxt.type);
3689                         break;
3690                 case Audit_not_equal:
3691                         match = (ctxt->type != rule->au_ctxt.type);
3692                         break;
3693                 }
3694                 break;
3695         case AUDIT_SUBJ_SEN:
3696         case AUDIT_SUBJ_CLR:
3697         case AUDIT_OBJ_LEV_LOW:
3698         case AUDIT_OBJ_LEV_HIGH:
3699                 level = ((field == AUDIT_SUBJ_SEN ||
3700                           field == AUDIT_OBJ_LEV_LOW) ?
3701                          &ctxt->range.level[0] : &ctxt->range.level[1]);
3702                 switch (op) {
3703                 case Audit_equal:
3704                         match = mls_level_eq(&rule->au_ctxt.range.level[0],
3705                                              level);
3706                         break;
3707                 case Audit_not_equal:
3708                         match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3709                                               level);
3710                         break;
3711                 case Audit_lt:
3712                         match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3713                                                level) &&
3714                                  !mls_level_eq(&rule->au_ctxt.range.level[0],
3715                                                level));
3716                         break;
3717                 case Audit_le:
3718                         match = mls_level_dom(&rule->au_ctxt.range.level[0],
3719                                               level);
3720                         break;
3721                 case Audit_gt:
3722                         match = (mls_level_dom(level,
3723                                               &rule->au_ctxt.range.level[0]) &&
3724                                  !mls_level_eq(level,
3725                                                &rule->au_ctxt.range.level[0]));
3726                         break;
3727                 case Audit_ge:
3728                         match = mls_level_dom(level,
3729                                               &rule->au_ctxt.range.level[0]);
3730                         break;
3731                 }
3732         }
3733
3734 out:
3735         rcu_read_unlock();
3736         return match;
3737 }
3738
3739 static int aurule_avc_callback(u32 event)
3740 {
3741         if (event == AVC_CALLBACK_RESET)
3742                 return audit_update_lsm_rules();
3743         return 0;
3744 }
3745
3746 static int __init aurule_init(void)
3747 {
3748         int err;
3749
3750         err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3751         if (err)
3752                 panic("avc_add_callback() failed, error %d\n", err);
3753
3754         return err;
3755 }
3756 __initcall(aurule_init);
3757
3758 #ifdef CONFIG_NETLABEL
3759 /**
3760  * security_netlbl_cache_add - Add an entry to the NetLabel cache
3761  * @secattr: the NetLabel packet security attributes
3762  * @sid: the SELinux SID
3763  *
3764  * Description:
3765  * Attempt to cache the context in @ctx, which was derived from the packet in
3766  * @skb, in the NetLabel subsystem cache.  This function assumes @secattr has
3767  * already been initialized.
3768  *
3769  */
3770 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3771                                       u32 sid)
3772 {
3773         u32 *sid_cache;
3774
3775         sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3776         if (sid_cache == NULL)
3777                 return;
3778         secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3779         if (secattr->cache == NULL) {
3780                 kfree(sid_cache);
3781                 return;
3782         }
3783
3784         *sid_cache = sid;
3785         secattr->cache->free = kfree;
3786         secattr->cache->data = sid_cache;
3787         secattr->flags |= NETLBL_SECATTR_CACHE;
3788 }
3789
3790 /**
3791  * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3792  * @secattr: the NetLabel packet security attributes
3793  * @sid: the SELinux SID
3794  *
3795  * Description:
3796  * Convert the given NetLabel security attributes in @secattr into a
3797  * SELinux SID.  If the @secattr field does not contain a full SELinux
3798  * SID/context then use SECINITSID_NETMSG as the foundation.  If possible the
3799  * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3800  * allow the @secattr to be used by NetLabel to cache the secattr to SID
3801  * conversion for future lookups.  Returns zero on success, negative values on
3802  * failure.
3803  *
3804  */
3805 int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
3806                                    u32 *sid)
3807 {
3808         struct selinux_policy *policy;
3809         struct policydb *policydb;
3810         struct sidtab *sidtab;
3811         int rc;
3812         struct context *ctx;
3813         struct context ctx_new;
3814
3815         if (!selinux_initialized()) {
3816                 *sid = SECSID_NULL;
3817                 return 0;
3818         }
3819
3820 retry:
3821         rc = 0;
3822         rcu_read_lock();
3823         policy = rcu_dereference(selinux_state.policy);
3824         policydb = &policy->policydb;
3825         sidtab = policy->sidtab;
3826
3827         if (secattr->flags & NETLBL_SECATTR_CACHE)
3828                 *sid = *(u32 *)secattr->cache->data;
3829         else if (secattr->flags & NETLBL_SECATTR_SECID)
3830                 *sid = secattr->attr.secid;
3831         else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3832                 rc = -EIDRM;
3833                 ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3834                 if (ctx == NULL)
3835                         goto out;
3836
3837                 context_init(&ctx_new);
3838                 ctx_new.user = ctx->user;
3839                 ctx_new.role = ctx->role;
3840                 ctx_new.type = ctx->type;
3841                 mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3842                 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3843                         rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3844                         if (rc)
3845                                 goto out;
3846                 }
3847                 rc = -EIDRM;
3848                 if (!mls_context_isvalid(policydb, &ctx_new)) {
3849                         ebitmap_destroy(&ctx_new.range.level[0].cat);
3850                         goto out;
3851                 }
3852
3853                 rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3854                 ebitmap_destroy(&ctx_new.range.level[0].cat);
3855                 if (rc == -ESTALE) {
3856                         rcu_read_unlock();
3857                         goto retry;
3858                 }
3859                 if (rc)
3860                         goto out;
3861
3862                 security_netlbl_cache_add(secattr, *sid);
3863         } else
3864                 *sid = SECSID_NULL;
3865
3866 out:
3867         rcu_read_unlock();
3868         return rc;
3869 }
3870
3871 /**
3872  * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3873  * @sid: the SELinux SID
3874  * @secattr: the NetLabel packet security attributes
3875  *
3876  * Description:
3877  * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3878  * Returns zero on success, negative values on failure.
3879  *
3880  */
3881 int security_netlbl_sid_to_secattr(u32 sid, struct netlbl_lsm_secattr *secattr)
3882 {
3883         struct selinux_policy *policy;
3884         struct policydb *policydb;
3885         int rc;
3886         struct context *ctx;
3887
3888         if (!selinux_initialized())
3889                 return 0;
3890
3891         rcu_read_lock();
3892         policy = rcu_dereference(selinux_state.policy);
3893         policydb = &policy->policydb;
3894
3895         rc = -ENOENT;
3896         ctx = sidtab_search(policy->sidtab, sid);
3897         if (ctx == NULL)
3898                 goto out;
3899
3900         rc = -ENOMEM;
3901         secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3902                                   GFP_ATOMIC);
3903         if (secattr->domain == NULL)
3904                 goto out;
3905
3906         secattr->attr.secid = sid;
3907         secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3908         mls_export_netlbl_lvl(policydb, ctx, secattr);
3909         rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3910 out:
3911         rcu_read_unlock();
3912         return rc;
3913 }
3914 #endif /* CONFIG_NETLABEL */
3915
3916 /**
3917  * __security_read_policy - read the policy.
3918  * @policy: SELinux policy
3919  * @data: binary policy data
3920  * @len: length of data in bytes
3921  *
3922  */
3923 static int __security_read_policy(struct selinux_policy *policy,
3924                                   void *data, size_t *len)
3925 {
3926         int rc;
3927         struct policy_file fp;
3928
3929         fp.data = data;
3930         fp.len = *len;
3931
3932         rc = policydb_write(&policy->policydb, &fp);
3933         if (rc)
3934                 return rc;
3935
3936         *len = (unsigned long)fp.data - (unsigned long)data;
3937         return 0;
3938 }
3939
3940 /**
3941  * security_read_policy - read the policy.
3942  * @data: binary policy data
3943  * @len: length of data in bytes
3944  *
3945  */
3946 int security_read_policy(void **data, size_t *len)
3947 {
3948         struct selinux_state *state = &selinux_state;
3949         struct selinux_policy *policy;
3950
3951         policy = rcu_dereference_protected(
3952                         state->policy, lockdep_is_held(&state->policy_mutex));
3953         if (!policy)
3954                 return -EINVAL;
3955
3956         *len = policy->policydb.len;
3957         *data = vmalloc_user(*len);
3958         if (!*data)
3959                 return -ENOMEM;
3960
3961         return __security_read_policy(policy, *data, len);
3962 }
3963
3964 /**
3965  * security_read_state_kernel - read the policy.
3966  * @data: binary policy data
3967  * @len: length of data in bytes
3968  *
3969  * Allocates kernel memory for reading SELinux policy.
3970  * This function is for internal use only and should not
3971  * be used for returning data to user space.
3972  *
3973  * This function must be called with policy_mutex held.
3974  */
3975 int security_read_state_kernel(void **data, size_t *len)
3976 {
3977         int err;
3978         struct selinux_state *state = &selinux_state;
3979         struct selinux_policy *policy;
3980
3981         policy = rcu_dereference_protected(
3982                         state->policy, lockdep_is_held(&state->policy_mutex));
3983         if (!policy)
3984                 return -EINVAL;
3985
3986         *len = policy->policydb.len;
3987         *data = vmalloc(*len);
3988         if (!*data)
3989                 return -ENOMEM;
3990
3991         err = __security_read_policy(policy, *data, len);
3992         if (err) {
3993                 vfree(*data);
3994                 *data = NULL;
3995                 *len = 0;
3996         }
3997         return err;
3998 }