Commit | Line | Data |
---|---|---|
e338d263 | 1 | /* Common capabilities, needed by capability.o and root_plug.o |
1da177e4 LT |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2 of the License, or | |
6 | * (at your option) any later version. | |
7 | * | |
8 | */ | |
9 | ||
c59ede7b | 10 | #include <linux/capability.h> |
3fc689e9 | 11 | #include <linux/audit.h> |
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/security.h> | |
16 | #include <linux/file.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/mman.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/swap.h> | |
1da177e4 LT |
21 | #include <linux/skbuff.h> |
22 | #include <linux/netlink.h> | |
23 | #include <linux/ptrace.h> | |
24 | #include <linux/xattr.h> | |
25 | #include <linux/hugetlb.h> | |
b5376771 | 26 | #include <linux/mount.h> |
b460cbc5 | 27 | #include <linux/sched.h> |
3898b1b4 AM |
28 | #include <linux/prctl.h> |
29 | #include <linux/securebits.h> | |
72c2d582 | 30 | |
1da177e4 LT |
31 | int cap_netlink_send(struct sock *sk, struct sk_buff *skb) |
32 | { | |
b6dff3ec | 33 | NETLINK_CB(skb).eff_cap = current_cap(); |
1da177e4 LT |
34 | return 0; |
35 | } | |
36 | ||
c7bdb545 | 37 | int cap_netlink_recv(struct sk_buff *skb, int cap) |
1da177e4 | 38 | { |
c7bdb545 | 39 | if (!cap_raised(NETLINK_CB(skb).eff_cap, cap)) |
1da177e4 LT |
40 | return -EPERM; |
41 | return 0; | |
42 | } | |
43 | ||
44 | EXPORT_SYMBOL(cap_netlink_recv); | |
45 | ||
a6dbb1ef AM |
46 | /* |
47 | * NOTE WELL: cap_capable() cannot be used like the kernel's capable() | |
48 | * function. That is, it has the reverse semantics: cap_capable() | |
49 | * returns 0 when a task has a capability, but the kernel's capable() | |
50 | * returns 1 for this case. | |
51 | */ | |
06112163 | 52 | int cap_capable(struct task_struct *tsk, int cap, int audit) |
1da177e4 | 53 | { |
c69e8d9c DH |
54 | __u32 cap_raised; |
55 | ||
1da177e4 | 56 | /* Derived from include/linux/sched.h:capable. */ |
c69e8d9c DH |
57 | rcu_read_lock(); |
58 | cap_raised = cap_raised(__task_cred(tsk)->cap_effective, cap); | |
59 | rcu_read_unlock(); | |
60 | return cap_raised ? 0 : -EPERM; | |
1da177e4 LT |
61 | } |
62 | ||
63 | int cap_settime(struct timespec *ts, struct timezone *tz) | |
64 | { | |
65 | if (!capable(CAP_SYS_TIME)) | |
66 | return -EPERM; | |
67 | return 0; | |
68 | } | |
69 | ||
5cd9c58f | 70 | int cap_ptrace_may_access(struct task_struct *child, unsigned int mode) |
1da177e4 | 71 | { |
c69e8d9c DH |
72 | int ret = 0; |
73 | ||
74 | rcu_read_lock(); | |
75 | if (!cap_issubset(child->cred->cap_permitted, | |
76 | current->cred->cap_permitted) && | |
77 | !capable(CAP_SYS_PTRACE)) | |
78 | ret = -EPERM; | |
79 | rcu_read_unlock(); | |
80 | return ret; | |
5cd9c58f DH |
81 | } |
82 | ||
83 | int cap_ptrace_traceme(struct task_struct *parent) | |
84 | { | |
c69e8d9c DH |
85 | int ret = 0; |
86 | ||
87 | rcu_read_lock(); | |
88 | if (!cap_issubset(current->cred->cap_permitted, | |
89 | parent->cred->cap_permitted) && | |
90 | !has_capability(parent, CAP_SYS_PTRACE)) | |
91 | ret = -EPERM; | |
92 | rcu_read_unlock(); | |
93 | return ret; | |
1da177e4 LT |
94 | } |
95 | ||
96 | int cap_capget (struct task_struct *target, kernel_cap_t *effective, | |
97 | kernel_cap_t *inheritable, kernel_cap_t *permitted) | |
98 | { | |
c69e8d9c | 99 | const struct cred *cred; |
b6dff3ec | 100 | |
1da177e4 | 101 | /* Derived from kernel/capability.c:sys_capget. */ |
c69e8d9c DH |
102 | rcu_read_lock(); |
103 | cred = __task_cred(target); | |
b6dff3ec DH |
104 | *effective = cred->cap_effective; |
105 | *inheritable = cred->cap_inheritable; | |
106 | *permitted = cred->cap_permitted; | |
c69e8d9c | 107 | rcu_read_unlock(); |
1da177e4 LT |
108 | return 0; |
109 | } | |
110 | ||
72c2d582 AM |
111 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES |
112 | ||
72c2d582 AM |
113 | static inline int cap_inh_is_capped(void) |
114 | { | |
115 | /* | |
a6dbb1ef AM |
116 | * Return 1 if changes to the inheritable set are limited |
117 | * to the old permitted set. That is, if the current task | |
118 | * does *not* possess the CAP_SETPCAP capability. | |
72c2d582 | 119 | */ |
06112163 | 120 | return (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0); |
72c2d582 AM |
121 | } |
122 | ||
1209726c AM |
123 | static inline int cap_limit_ptraced_target(void) { return 1; } |
124 | ||
72c2d582 AM |
125 | #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */ |
126 | ||
72c2d582 | 127 | static inline int cap_inh_is_capped(void) { return 1; } |
1209726c AM |
128 | static inline int cap_limit_ptraced_target(void) |
129 | { | |
130 | return !capable(CAP_SETPCAP); | |
131 | } | |
72c2d582 AM |
132 | |
133 | #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */ | |
134 | ||
15a2460e DH |
135 | int cap_capset_check(const kernel_cap_t *effective, |
136 | const kernel_cap_t *inheritable, | |
137 | const kernel_cap_t *permitted) | |
1da177e4 | 138 | { |
b6dff3ec DH |
139 | const struct cred *cred = current->cred; |
140 | ||
72c2d582 AM |
141 | if (cap_inh_is_capped() |
142 | && !cap_issubset(*inheritable, | |
b6dff3ec DH |
143 | cap_combine(cred->cap_inheritable, |
144 | cred->cap_permitted))) { | |
72c2d582 | 145 | /* incapable of using this inheritable set */ |
1da177e4 LT |
146 | return -EPERM; |
147 | } | |
3b7391de | 148 | if (!cap_issubset(*inheritable, |
b6dff3ec DH |
149 | cap_combine(cred->cap_inheritable, |
150 | cred->cap_bset))) { | |
3b7391de SH |
151 | /* no new pI capabilities outside bounding set */ |
152 | return -EPERM; | |
153 | } | |
1da177e4 LT |
154 | |
155 | /* verify restrictions on target's new Permitted set */ | |
156 | if (!cap_issubset (*permitted, | |
b6dff3ec DH |
157 | cap_combine (cred->cap_permitted, |
158 | cred->cap_permitted))) { | |
1da177e4 LT |
159 | return -EPERM; |
160 | } | |
161 | ||
162 | /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ | |
163 | if (!cap_issubset (*effective, *permitted)) { | |
164 | return -EPERM; | |
165 | } | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
15a2460e DH |
170 | void cap_capset_set(const kernel_cap_t *effective, |
171 | const kernel_cap_t *inheritable, | |
172 | const kernel_cap_t *permitted) | |
1da177e4 | 173 | { |
b6dff3ec DH |
174 | struct cred *cred = current->cred; |
175 | ||
176 | cred->cap_effective = *effective; | |
177 | cred->cap_inheritable = *inheritable; | |
178 | cred->cap_permitted = *permitted; | |
1da177e4 LT |
179 | } |
180 | ||
b5376771 SH |
181 | static inline void bprm_clear_caps(struct linux_binprm *bprm) |
182 | { | |
5459c164 | 183 | cap_clear(bprm->cap_post_exec_permitted); |
b5376771 SH |
184 | bprm->cap_effective = false; |
185 | } | |
186 | ||
187 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES | |
188 | ||
189 | int cap_inode_need_killpriv(struct dentry *dentry) | |
190 | { | |
191 | struct inode *inode = dentry->d_inode; | |
192 | int error; | |
193 | ||
194 | if (!inode->i_op || !inode->i_op->getxattr) | |
195 | return 0; | |
196 | ||
197 | error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0); | |
198 | if (error <= 0) | |
199 | return 0; | |
200 | return 1; | |
201 | } | |
202 | ||
203 | int cap_inode_killpriv(struct dentry *dentry) | |
204 | { | |
205 | struct inode *inode = dentry->d_inode; | |
206 | ||
207 | if (!inode->i_op || !inode->i_op->removexattr) | |
208 | return 0; | |
209 | ||
210 | return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS); | |
211 | } | |
212 | ||
c0b00441 EP |
213 | static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, |
214 | struct linux_binprm *bprm) | |
b5376771 | 215 | { |
c0b00441 EP |
216 | unsigned i; |
217 | int ret = 0; | |
218 | ||
219 | if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) | |
220 | bprm->cap_effective = true; | |
221 | else | |
222 | bprm->cap_effective = false; | |
223 | ||
224 | CAP_FOR_EACH_U32(i) { | |
225 | __u32 permitted = caps->permitted.cap[i]; | |
226 | __u32 inheritable = caps->inheritable.cap[i]; | |
227 | ||
228 | /* | |
229 | * pP' = (X & fP) | (pI & fI) | |
230 | */ | |
231 | bprm->cap_post_exec_permitted.cap[i] = | |
b6dff3ec DH |
232 | (current->cred->cap_bset.cap[i] & permitted) | |
233 | (current->cred->cap_inheritable.cap[i] & inheritable); | |
c0b00441 EP |
234 | |
235 | if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) { | |
236 | /* | |
237 | * insufficient to execute correctly | |
238 | */ | |
239 | ret = -EPERM; | |
240 | } | |
241 | } | |
242 | ||
243 | /* | |
244 | * For legacy apps, with no internal support for recognizing they | |
245 | * do not have enough capabilities, we return an error if they are | |
246 | * missing some "forced" (aka file-permitted) capabilities. | |
247 | */ | |
248 | return bprm->cap_effective ? ret : 0; | |
249 | } | |
250 | ||
251 | int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) | |
252 | { | |
253 | struct inode *inode = dentry->d_inode; | |
b5376771 | 254 | __u32 magic_etc; |
e338d263 | 255 | unsigned tocopy, i; |
c0b00441 EP |
256 | int size; |
257 | struct vfs_cap_data caps; | |
258 | ||
259 | memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); | |
260 | ||
261 | if (!inode || !inode->i_op || !inode->i_op->getxattr) | |
262 | return -ENODATA; | |
263 | ||
264 | size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps, | |
265 | XATTR_CAPS_SZ); | |
266 | if (size == -ENODATA || size == -EOPNOTSUPP) { | |
267 | /* no data, that's ok */ | |
268 | return -ENODATA; | |
269 | } | |
270 | if (size < 0) | |
271 | return size; | |
b5376771 | 272 | |
e338d263 | 273 | if (size < sizeof(magic_etc)) |
b5376771 SH |
274 | return -EINVAL; |
275 | ||
c0b00441 | 276 | cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc); |
b5376771 SH |
277 | |
278 | switch ((magic_etc & VFS_CAP_REVISION_MASK)) { | |
e338d263 AM |
279 | case VFS_CAP_REVISION_1: |
280 | if (size != XATTR_CAPS_SZ_1) | |
281 | return -EINVAL; | |
282 | tocopy = VFS_CAP_U32_1; | |
283 | break; | |
284 | case VFS_CAP_REVISION_2: | |
285 | if (size != XATTR_CAPS_SZ_2) | |
286 | return -EINVAL; | |
287 | tocopy = VFS_CAP_U32_2; | |
288 | break; | |
b5376771 SH |
289 | default: |
290 | return -EINVAL; | |
291 | } | |
e338d263 | 292 | |
5459c164 | 293 | CAP_FOR_EACH_U32(i) { |
c0b00441 EP |
294 | if (i >= tocopy) |
295 | break; | |
296 | cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted); | |
297 | cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable); | |
e338d263 | 298 | } |
c0b00441 | 299 | return 0; |
b5376771 SH |
300 | } |
301 | ||
302 | /* Locate any VFS capabilities: */ | |
303 | static int get_file_caps(struct linux_binprm *bprm) | |
304 | { | |
305 | struct dentry *dentry; | |
306 | int rc = 0; | |
c0b00441 | 307 | struct cpu_vfs_cap_data vcaps; |
b5376771 | 308 | |
3318a386 SH |
309 | bprm_clear_caps(bprm); |
310 | ||
1f29fae2 SH |
311 | if (!file_caps_enabled) |
312 | return 0; | |
313 | ||
3318a386 | 314 | if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) |
b5376771 | 315 | return 0; |
b5376771 SH |
316 | |
317 | dentry = dget(bprm->file->f_dentry); | |
b5376771 | 318 | |
c0b00441 EP |
319 | rc = get_vfs_caps_from_disk(dentry, &vcaps); |
320 | if (rc < 0) { | |
321 | if (rc == -EINVAL) | |
322 | printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n", | |
323 | __func__, rc, bprm->filename); | |
324 | else if (rc == -ENODATA) | |
325 | rc = 0; | |
b5376771 SH |
326 | goto out; |
327 | } | |
b5376771 | 328 | |
c0b00441 | 329 | rc = bprm_caps_from_vfs_caps(&vcaps, bprm); |
b5376771 SH |
330 | |
331 | out: | |
332 | dput(dentry); | |
333 | if (rc) | |
334 | bprm_clear_caps(bprm); | |
335 | ||
336 | return rc; | |
337 | } | |
338 | ||
339 | #else | |
340 | int cap_inode_need_killpriv(struct dentry *dentry) | |
341 | { | |
342 | return 0; | |
343 | } | |
344 | ||
345 | int cap_inode_killpriv(struct dentry *dentry) | |
346 | { | |
347 | return 0; | |
348 | } | |
349 | ||
350 | static inline int get_file_caps(struct linux_binprm *bprm) | |
351 | { | |
352 | bprm_clear_caps(bprm); | |
353 | return 0; | |
354 | } | |
355 | #endif | |
356 | ||
1da177e4 LT |
357 | int cap_bprm_set_security (struct linux_binprm *bprm) |
358 | { | |
b5376771 | 359 | int ret; |
1da177e4 | 360 | |
b5376771 | 361 | ret = get_file_caps(bprm); |
1da177e4 | 362 | |
5459c164 AM |
363 | if (!issecure(SECURE_NOROOT)) { |
364 | /* | |
365 | * To support inheritance of root-permissions and suid-root | |
366 | * executables under compatibility mode, we override the | |
367 | * capability sets for the file. | |
368 | * | |
369 | * If only the real uid is 0, we do not set the effective | |
370 | * bit. | |
371 | */ | |
b103c598 | 372 | if (bprm->e_uid == 0 || current_uid() == 0) { |
5459c164 AM |
373 | /* pP' = (cap_bset & ~0) | (pI & ~0) */ |
374 | bprm->cap_post_exec_permitted = cap_combine( | |
b6dff3ec DH |
375 | current->cred->cap_bset, |
376 | current->cred->cap_inheritable); | |
5459c164 AM |
377 | bprm->cap_effective = (bprm->e_uid == 0); |
378 | ret = 0; | |
1da177e4 | 379 | } |
1da177e4 | 380 | } |
b5376771 SH |
381 | |
382 | return ret; | |
1da177e4 LT |
383 | } |
384 | ||
385 | void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe) | |
386 | { | |
b6dff3ec | 387 | struct cred *cred = current->cred; |
3fc689e9 | 388 | |
b6dff3ec | 389 | if (bprm->e_uid != cred->uid || bprm->e_gid != cred->gid || |
5459c164 | 390 | !cap_issubset(bprm->cap_post_exec_permitted, |
b6dff3ec | 391 | cred->cap_permitted)) { |
6c5d5238 | 392 | set_dumpable(current->mm, suid_dumpable); |
b5376771 | 393 | current->pdeath_signal = 0; |
1da177e4 LT |
394 | |
395 | if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) { | |
396 | if (!capable(CAP_SETUID)) { | |
b6dff3ec DH |
397 | bprm->e_uid = cred->uid; |
398 | bprm->e_gid = cred->gid; | |
1da177e4 | 399 | } |
1209726c | 400 | if (cap_limit_ptraced_target()) { |
5459c164 AM |
401 | bprm->cap_post_exec_permitted = cap_intersect( |
402 | bprm->cap_post_exec_permitted, | |
b6dff3ec | 403 | cred->cap_permitted); |
1da177e4 LT |
404 | } |
405 | } | |
406 | } | |
407 | ||
b6dff3ec DH |
408 | cred->suid = cred->euid = cred->fsuid = bprm->e_uid; |
409 | cred->sgid = cred->egid = cred->fsgid = bprm->e_gid; | |
1da177e4 LT |
410 | |
411 | /* For init, we want to retain the capabilities set | |
412 | * in the init_task struct. Thus we skip the usual | |
413 | * capability rules */ | |
b460cbc5 | 414 | if (!is_global_init(current)) { |
b6dff3ec | 415 | cred->cap_permitted = bprm->cap_post_exec_permitted; |
e338d263 | 416 | if (bprm->cap_effective) |
b6dff3ec | 417 | cred->cap_effective = bprm->cap_post_exec_permitted; |
e338d263 | 418 | else |
b6dff3ec | 419 | cap_clear(cred->cap_effective); |
1da177e4 LT |
420 | } |
421 | ||
3fc689e9 EP |
422 | /* |
423 | * Audit candidate if current->cap_effective is set | |
424 | * | |
425 | * We do not bother to audit if 3 things are true: | |
426 | * 1) cap_effective has all caps | |
427 | * 2) we are root | |
428 | * 3) root is supposed to have all caps (SECURE_NOROOT) | |
429 | * Since this is just a normal root execing a process. | |
430 | * | |
431 | * Number 1 above might fail if you don't have a full bset, but I think | |
432 | * that is interesting information to audit. | |
433 | */ | |
b6dff3ec DH |
434 | if (!cap_isclear(cred->cap_effective)) { |
435 | if (!cap_issubset(CAP_FULL_SET, cred->cap_effective) || | |
436 | (bprm->e_uid != 0) || (cred->uid != 0) || | |
3fc689e9 | 437 | issecure(SECURE_NOROOT)) |
b6dff3ec DH |
438 | audit_log_bprm_fcaps(bprm, &cred->cap_permitted, |
439 | &cred->cap_effective); | |
3fc689e9 | 440 | } |
1da177e4 | 441 | |
b6dff3ec | 442 | cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
1da177e4 LT |
443 | } |
444 | ||
445 | int cap_bprm_secureexec (struct linux_binprm *bprm) | |
446 | { | |
c69e8d9c | 447 | const struct cred *cred = current_cred(); |
b6dff3ec DH |
448 | |
449 | if (cred->uid != 0) { | |
b5376771 SH |
450 | if (bprm->cap_effective) |
451 | return 1; | |
5459c164 | 452 | if (!cap_isclear(bprm->cap_post_exec_permitted)) |
b5376771 SH |
453 | return 1; |
454 | } | |
455 | ||
b6dff3ec DH |
456 | return (cred->euid != cred->uid || |
457 | cred->egid != cred->gid); | |
1da177e4 LT |
458 | } |
459 | ||
8f0cfa52 DH |
460 | int cap_inode_setxattr(struct dentry *dentry, const char *name, |
461 | const void *value, size_t size, int flags) | |
1da177e4 | 462 | { |
b5376771 SH |
463 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
464 | if (!capable(CAP_SETFCAP)) | |
465 | return -EPERM; | |
466 | return 0; | |
467 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
1da177e4 LT |
468 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
469 | !capable(CAP_SYS_ADMIN)) | |
470 | return -EPERM; | |
471 | return 0; | |
472 | } | |
473 | ||
8f0cfa52 | 474 | int cap_inode_removexattr(struct dentry *dentry, const char *name) |
1da177e4 | 475 | { |
b5376771 SH |
476 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
477 | if (!capable(CAP_SETFCAP)) | |
478 | return -EPERM; | |
479 | return 0; | |
480 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
1da177e4 LT |
481 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
482 | !capable(CAP_SYS_ADMIN)) | |
483 | return -EPERM; | |
484 | return 0; | |
485 | } | |
486 | ||
487 | /* moved from kernel/sys.c. */ | |
488 | /* | |
489 | * cap_emulate_setxuid() fixes the effective / permitted capabilities of | |
490 | * a process after a call to setuid, setreuid, or setresuid. | |
491 | * | |
492 | * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of | |
493 | * {r,e,s}uid != 0, the permitted and effective capabilities are | |
494 | * cleared. | |
495 | * | |
496 | * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective | |
497 | * capabilities of the process are cleared. | |
498 | * | |
499 | * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective | |
500 | * capabilities are set to the permitted capabilities. | |
501 | * | |
502 | * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should | |
503 | * never happen. | |
504 | * | |
505 | * -astor | |
506 | * | |
507 | * cevans - New behaviour, Oct '99 | |
508 | * A process may, via prctl(), elect to keep its capabilities when it | |
509 | * calls setuid() and switches away from uid==0. Both permitted and | |
510 | * effective sets will be retained. | |
511 | * Without this change, it was impossible for a daemon to drop only some | |
512 | * of its privilege. The call to setuid(!=0) would drop all privileges! | |
513 | * Keeping uid 0 is not an option because uid 0 owns too many vital | |
514 | * files.. | |
515 | * Thanks to Olaf Kirch and Peter Benie for spotting this. | |
516 | */ | |
517 | static inline void cap_emulate_setxuid (int old_ruid, int old_euid, | |
518 | int old_suid) | |
519 | { | |
b6dff3ec | 520 | struct cred *cred = current->cred; |
b103c598 | 521 | |
1da177e4 | 522 | if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) && |
b6dff3ec | 523 | (cred->uid != 0 && cred->euid != 0 && cred->suid != 0) && |
3898b1b4 | 524 | !issecure(SECURE_KEEP_CAPS)) { |
c69e8d9c DH |
525 | cap_clear(cred->cap_permitted); |
526 | cap_clear(cred->cap_effective); | |
1da177e4 | 527 | } |
b6dff3ec | 528 | if (old_euid == 0 && cred->euid != 0) { |
c69e8d9c | 529 | cap_clear(cred->cap_effective); |
1da177e4 | 530 | } |
b6dff3ec DH |
531 | if (old_euid != 0 && cred->euid == 0) { |
532 | cred->cap_effective = cred->cap_permitted; | |
1da177e4 LT |
533 | } |
534 | } | |
535 | ||
536 | int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid, | |
537 | int flags) | |
538 | { | |
b6dff3ec DH |
539 | struct cred *cred = current->cred; |
540 | ||
1da177e4 LT |
541 | switch (flags) { |
542 | case LSM_SETID_RE: | |
543 | case LSM_SETID_ID: | |
544 | case LSM_SETID_RES: | |
545 | /* Copied from kernel/sys.c:setreuid/setuid/setresuid. */ | |
546 | if (!issecure (SECURE_NO_SETUID_FIXUP)) { | |
547 | cap_emulate_setxuid (old_ruid, old_euid, old_suid); | |
548 | } | |
549 | break; | |
550 | case LSM_SETID_FS: | |
551 | { | |
552 | uid_t old_fsuid = old_ruid; | |
553 | ||
554 | /* Copied from kernel/sys.c:setfsuid. */ | |
555 | ||
556 | /* | |
557 | * FIXME - is fsuser used for all CAP_FS_MASK capabilities? | |
558 | * if not, we might be a bit too harsh here. | |
559 | */ | |
560 | ||
561 | if (!issecure (SECURE_NO_SETUID_FIXUP)) { | |
b6dff3ec DH |
562 | if (old_fsuid == 0 && cred->fsuid != 0) { |
563 | cred->cap_effective = | |
e338d263 | 564 | cap_drop_fs_set( |
b6dff3ec | 565 | cred->cap_effective); |
1da177e4 | 566 | } |
b6dff3ec DH |
567 | if (old_fsuid != 0 && cred->fsuid == 0) { |
568 | cred->cap_effective = | |
e338d263 | 569 | cap_raise_fs_set( |
b6dff3ec DH |
570 | cred->cap_effective, |
571 | cred->cap_permitted); | |
1da177e4 LT |
572 | } |
573 | } | |
574 | break; | |
575 | } | |
576 | default: | |
577 | return -EINVAL; | |
578 | } | |
579 | ||
580 | return 0; | |
581 | } | |
582 | ||
b5376771 SH |
583 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES |
584 | /* | |
585 | * Rationale: code calling task_setscheduler, task_setioprio, and | |
586 | * task_setnice, assumes that | |
587 | * . if capable(cap_sys_nice), then those actions should be allowed | |
588 | * . if not capable(cap_sys_nice), but acting on your own processes, | |
589 | * then those actions should be allowed | |
590 | * This is insufficient now since you can call code without suid, but | |
591 | * yet with increased caps. | |
592 | * So we check for increased caps on the target process. | |
593 | */ | |
de45e806 | 594 | static int cap_safe_nice(struct task_struct *p) |
b5376771 | 595 | { |
c69e8d9c DH |
596 | int is_subset; |
597 | ||
598 | rcu_read_lock(); | |
599 | is_subset = cap_issubset(__task_cred(p)->cap_permitted, | |
600 | current_cred()->cap_permitted); | |
601 | rcu_read_unlock(); | |
602 | ||
603 | if (!is_subset && !capable(CAP_SYS_NICE)) | |
b5376771 SH |
604 | return -EPERM; |
605 | return 0; | |
606 | } | |
607 | ||
608 | int cap_task_setscheduler (struct task_struct *p, int policy, | |
609 | struct sched_param *lp) | |
610 | { | |
611 | return cap_safe_nice(p); | |
612 | } | |
613 | ||
614 | int cap_task_setioprio (struct task_struct *p, int ioprio) | |
615 | { | |
616 | return cap_safe_nice(p); | |
617 | } | |
618 | ||
619 | int cap_task_setnice (struct task_struct *p, int nice) | |
620 | { | |
621 | return cap_safe_nice(p); | |
622 | } | |
623 | ||
3b7391de SH |
624 | /* |
625 | * called from kernel/sys.c for prctl(PR_CABSET_DROP) | |
626 | * done without task_capability_lock() because it introduces | |
627 | * no new races - i.e. only another task doing capget() on | |
628 | * this task could get inconsistent info. There can be no | |
629 | * racing writer bc a task can only change its own caps. | |
630 | */ | |
3898b1b4 | 631 | static long cap_prctl_drop(unsigned long cap) |
3b7391de SH |
632 | { |
633 | if (!capable(CAP_SETPCAP)) | |
634 | return -EPERM; | |
635 | if (!cap_valid(cap)) | |
636 | return -EINVAL; | |
b6dff3ec | 637 | cap_lower(current->cred->cap_bset, cap); |
3b7391de SH |
638 | return 0; |
639 | } | |
3898b1b4 | 640 | |
b5376771 SH |
641 | #else |
642 | int cap_task_setscheduler (struct task_struct *p, int policy, | |
643 | struct sched_param *lp) | |
644 | { | |
645 | return 0; | |
646 | } | |
647 | int cap_task_setioprio (struct task_struct *p, int ioprio) | |
648 | { | |
649 | return 0; | |
650 | } | |
651 | int cap_task_setnice (struct task_struct *p, int nice) | |
652 | { | |
653 | return 0; | |
654 | } | |
b5376771 SH |
655 | #endif |
656 | ||
3898b1b4 AM |
657 | int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, |
658 | unsigned long arg4, unsigned long arg5, long *rc_p) | |
659 | { | |
86a264ab | 660 | struct cred *cred = current_cred(); |
3898b1b4 AM |
661 | long error = 0; |
662 | ||
663 | switch (option) { | |
664 | case PR_CAPBSET_READ: | |
665 | if (!cap_valid(arg2)) | |
666 | error = -EINVAL; | |
667 | else | |
b6dff3ec | 668 | error = !!cap_raised(cred->cap_bset, arg2); |
3898b1b4 AM |
669 | break; |
670 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES | |
671 | case PR_CAPBSET_DROP: | |
672 | error = cap_prctl_drop(arg2); | |
673 | break; | |
674 | ||
675 | /* | |
676 | * The next four prctl's remain to assist with transitioning a | |
677 | * system from legacy UID=0 based privilege (when filesystem | |
678 | * capabilities are not in use) to a system using filesystem | |
679 | * capabilities only - as the POSIX.1e draft intended. | |
680 | * | |
681 | * Note: | |
682 | * | |
683 | * PR_SET_SECUREBITS = | |
684 | * issecure_mask(SECURE_KEEP_CAPS_LOCKED) | |
685 | * | issecure_mask(SECURE_NOROOT) | |
686 | * | issecure_mask(SECURE_NOROOT_LOCKED) | |
687 | * | issecure_mask(SECURE_NO_SETUID_FIXUP) | |
688 | * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) | |
689 | * | |
690 | * will ensure that the current process and all of its | |
691 | * children will be locked into a pure | |
692 | * capability-based-privilege environment. | |
693 | */ | |
694 | case PR_SET_SECUREBITS: | |
b6dff3ec DH |
695 | if ((((cred->securebits & SECURE_ALL_LOCKS) >> 1) |
696 | & (cred->securebits ^ arg2)) /*[1]*/ | |
697 | || ((cred->securebits & SECURE_ALL_LOCKS | |
3898b1b4 AM |
698 | & ~arg2)) /*[2]*/ |
699 | || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ | |
06112163 | 700 | || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0)) { /*[4]*/ |
3898b1b4 AM |
701 | /* |
702 | * [1] no changing of bits that are locked | |
703 | * [2] no unlocking of locks | |
704 | * [3] no setting of unsupported bits | |
705 | * [4] doing anything requires privilege (go read about | |
706 | * the "sendmail capabilities bug") | |
707 | */ | |
708 | error = -EPERM; /* cannot change a locked bit */ | |
709 | } else { | |
b6dff3ec | 710 | cred->securebits = arg2; |
3898b1b4 AM |
711 | } |
712 | break; | |
713 | case PR_GET_SECUREBITS: | |
b6dff3ec | 714 | error = cred->securebits; |
3898b1b4 AM |
715 | break; |
716 | ||
717 | #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */ | |
718 | ||
719 | case PR_GET_KEEPCAPS: | |
720 | if (issecure(SECURE_KEEP_CAPS)) | |
721 | error = 1; | |
722 | break; | |
723 | case PR_SET_KEEPCAPS: | |
724 | if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ | |
725 | error = -EINVAL; | |
726 | else if (issecure(SECURE_KEEP_CAPS_LOCKED)) | |
727 | error = -EPERM; | |
728 | else if (arg2) | |
b6dff3ec | 729 | cred->securebits |= issecure_mask(SECURE_KEEP_CAPS); |
3898b1b4 | 730 | else |
b6dff3ec | 731 | cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
3898b1b4 AM |
732 | break; |
733 | ||
734 | default: | |
735 | /* No functionality available - continue with default */ | |
736 | return 0; | |
737 | } | |
738 | ||
739 | /* Functionality provided */ | |
740 | *rc_p = error; | |
741 | return 1; | |
742 | } | |
743 | ||
1da177e4 LT |
744 | void cap_task_reparent_to_init (struct task_struct *p) |
745 | { | |
b6dff3ec DH |
746 | struct cred *cred = p->cred; |
747 | ||
748 | cap_set_init_eff(cred->cap_effective); | |
749 | cap_clear(cred->cap_inheritable); | |
750 | cap_set_full(cred->cap_permitted); | |
751 | p->cred->securebits = SECUREBITS_DEFAULT; | |
1da177e4 LT |
752 | } |
753 | ||
754 | int cap_syslog (int type) | |
755 | { | |
756 | if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN)) | |
757 | return -EPERM; | |
758 | return 0; | |
759 | } | |
760 | ||
34b4e4aa | 761 | int cap_vm_enough_memory(struct mm_struct *mm, long pages) |
1da177e4 LT |
762 | { |
763 | int cap_sys_admin = 0; | |
764 | ||
06112163 | 765 | if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0) |
1da177e4 | 766 | cap_sys_admin = 1; |
34b4e4aa | 767 | return __vm_enough_memory(mm, pages, cap_sys_admin); |
1da177e4 LT |
768 | } |
769 |