Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
3e1c2515 | 2 | /* Common capabilities, needed by capability.o. |
1da177e4 LT |
3 | */ |
4 | ||
c59ede7b | 5 | #include <linux/capability.h> |
3fc689e9 | 6 | #include <linux/audit.h> |
1da177e4 LT |
7 | #include <linux/init.h> |
8 | #include <linux/kernel.h> | |
b1d9e6b0 | 9 | #include <linux/lsm_hooks.h> |
1da177e4 LT |
10 | #include <linux/file.h> |
11 | #include <linux/mm.h> | |
12 | #include <linux/mman.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/swap.h> | |
1da177e4 LT |
15 | #include <linux/skbuff.h> |
16 | #include <linux/netlink.h> | |
17 | #include <linux/ptrace.h> | |
18 | #include <linux/xattr.h> | |
19 | #include <linux/hugetlb.h> | |
b5376771 | 20 | #include <linux/mount.h> |
b460cbc5 | 21 | #include <linux/sched.h> |
3898b1b4 AM |
22 | #include <linux/prctl.h> |
23 | #include <linux/securebits.h> | |
3486740a | 24 | #include <linux/user_namespace.h> |
40401530 | 25 | #include <linux/binfmts.h> |
51b79bee | 26 | #include <linux/personality.h> |
a793d79e | 27 | #include <linux/mnt_idmapping.h> |
f3b8788c | 28 | #include <uapi/linux/lsm.h> |
72c2d582 | 29 | |
b5f22a59 SH |
30 | /* |
31 | * If a non-root user executes a setuid-root binary in | |
32 | * !secure(SECURE_NOROOT) mode, then we raise capabilities. | |
33 | * However if fE is also set, then the intent is for only | |
34 | * the file capabilities to be applied, and the setuid-root | |
35 | * bit is left on either to change the uid (plausible) or | |
36 | * to get full privilege on a kernel without file capabilities | |
37 | * support. So in that case we do not raise capabilities. | |
38 | * | |
39 | * Warn if that happens, once per boot. | |
40 | */ | |
d7627467 | 41 | static void warn_setuid_and_fcaps_mixed(const char *fname) |
b5f22a59 SH |
42 | { |
43 | static int warned; | |
44 | if (!warned) { | |
45 | printk(KERN_INFO "warning: `%s' has both setuid-root and" | |
46 | " effective capabilities. Therefore not raising all" | |
47 | " capabilities.\n", fname); | |
48 | warned = 1; | |
49 | } | |
50 | } | |
51 | ||
1d045980 DH |
52 | /** |
53 | * cap_capable - Determine whether a task has a particular effective capability | |
3699c53c | 54 | * @cred: The credentials to use |
049ae601 | 55 | * @targ_ns: The user namespace in which we need the capability |
1d045980 | 56 | * @cap: The capability to check for |
e88ed488 | 57 | * @opts: Bitmask of options defined in include/linux/security.h |
1d045980 DH |
58 | * |
59 | * Determine whether the nominated task has the specified capability amongst | |
60 | * its effective set, returning 0 if it does, -ve if it does not. | |
61 | * | |
3699c53c DH |
62 | * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable() |
63 | * and has_capability() functions. That is, it has the reverse semantics: | |
64 | * cap_has_capability() returns 0 when a task has a capability, but the | |
65 | * kernel's capable() and has_capability() returns 1 for this case. | |
a6dbb1ef | 66 | */ |
6a9de491 | 67 | int cap_capable(const struct cred *cred, struct user_namespace *targ_ns, |
c1a85a00 | 68 | int cap, unsigned int opts) |
1da177e4 | 69 | { |
520d9eab | 70 | struct user_namespace *ns = targ_ns; |
3486740a | 71 | |
520d9eab EB |
72 | /* See if cred has the capability in the target user namespace |
73 | * by examining the target user namespace and all of the target | |
74 | * user namespace's parents. | |
75 | */ | |
76 | for (;;) { | |
3486740a | 77 | /* Do we have the necessary capabilities? */ |
520d9eab | 78 | if (ns == cred->user_ns) |
3486740a SH |
79 | return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM; |
80 | ||
64db4c7f KT |
81 | /* |
82 | * If we're already at a lower level than we're looking for, | |
83 | * we're done searching. | |
84 | */ | |
85 | if (ns->level <= cred->user_ns->level) | |
3486740a SH |
86 | return -EPERM; |
87 | ||
520d9eab EB |
88 | /* |
89 | * The owner of the user namespace in the parent of the | |
90 | * user namespace has all caps. | |
91 | */ | |
92 | if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid)) | |
93 | return 0; | |
94 | ||
3486740a | 95 | /* |
520d9eab | 96 | * If you have a capability in a parent user ns, then you have |
3486740a SH |
97 | * it over all children user namespaces as well. |
98 | */ | |
520d9eab | 99 | ns = ns->parent; |
3486740a SH |
100 | } |
101 | ||
102 | /* We never get here */ | |
1da177e4 LT |
103 | } |
104 | ||
1d045980 DH |
105 | /** |
106 | * cap_settime - Determine whether the current process may set the system clock | |
107 | * @ts: The time to set | |
108 | * @tz: The timezone to set | |
109 | * | |
110 | * Determine whether the current process may set the system clock and timezone | |
111 | * information, returning 0 if permission granted, -ve if denied. | |
112 | */ | |
457db29b | 113 | int cap_settime(const struct timespec64 *ts, const struct timezone *tz) |
1da177e4 LT |
114 | { |
115 | if (!capable(CAP_SYS_TIME)) | |
116 | return -EPERM; | |
117 | return 0; | |
118 | } | |
119 | ||
1d045980 | 120 | /** |
9e48858f | 121 | * cap_ptrace_access_check - Determine whether the current process may access |
1d045980 DH |
122 | * another |
123 | * @child: The process to be accessed | |
124 | * @mode: The mode of attachment. | |
125 | * | |
8409cca7 SH |
126 | * If we are in the same or an ancestor user_ns and have all the target |
127 | * task's capabilities, then ptrace access is allowed. | |
128 | * If we have the ptrace capability to the target user_ns, then ptrace | |
129 | * access is allowed. | |
130 | * Else denied. | |
131 | * | |
1d045980 DH |
132 | * Determine whether a process may access another, returning 0 if permission |
133 | * granted, -ve if denied. | |
134 | */ | |
9e48858f | 135 | int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) |
1da177e4 | 136 | { |
c69e8d9c | 137 | int ret = 0; |
8409cca7 | 138 | const struct cred *cred, *child_cred; |
caaee623 | 139 | const kernel_cap_t *caller_caps; |
c69e8d9c DH |
140 | |
141 | rcu_read_lock(); | |
8409cca7 SH |
142 | cred = current_cred(); |
143 | child_cred = __task_cred(child); | |
caaee623 JH |
144 | if (mode & PTRACE_MODE_FSCREDS) |
145 | caller_caps = &cred->cap_effective; | |
146 | else | |
147 | caller_caps = &cred->cap_permitted; | |
c4a4d603 | 148 | if (cred->user_ns == child_cred->user_ns && |
caaee623 | 149 | cap_issubset(child_cred->cap_permitted, *caller_caps)) |
8409cca7 | 150 | goto out; |
c4a4d603 | 151 | if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
152 | goto out; |
153 | ret = -EPERM; | |
154 | out: | |
c69e8d9c DH |
155 | rcu_read_unlock(); |
156 | return ret; | |
5cd9c58f DH |
157 | } |
158 | ||
1d045980 DH |
159 | /** |
160 | * cap_ptrace_traceme - Determine whether another process may trace the current | |
161 | * @parent: The task proposed to be the tracer | |
162 | * | |
8409cca7 SH |
163 | * If parent is in the same or an ancestor user_ns and has all current's |
164 | * capabilities, then ptrace access is allowed. | |
165 | * If parent has the ptrace capability to current's user_ns, then ptrace | |
166 | * access is allowed. | |
167 | * Else denied. | |
168 | * | |
1d045980 DH |
169 | * Determine whether the nominated task is permitted to trace the current |
170 | * process, returning 0 if permission is granted, -ve if denied. | |
171 | */ | |
5cd9c58f DH |
172 | int cap_ptrace_traceme(struct task_struct *parent) |
173 | { | |
c69e8d9c | 174 | int ret = 0; |
8409cca7 | 175 | const struct cred *cred, *child_cred; |
c69e8d9c DH |
176 | |
177 | rcu_read_lock(); | |
8409cca7 SH |
178 | cred = __task_cred(parent); |
179 | child_cred = current_cred(); | |
c4a4d603 | 180 | if (cred->user_ns == child_cred->user_ns && |
8409cca7 SH |
181 | cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) |
182 | goto out; | |
c4a4d603 | 183 | if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
184 | goto out; |
185 | ret = -EPERM; | |
186 | out: | |
c69e8d9c DH |
187 | rcu_read_unlock(); |
188 | return ret; | |
1da177e4 LT |
189 | } |
190 | ||
1d045980 DH |
191 | /** |
192 | * cap_capget - Retrieve a task's capability sets | |
193 | * @target: The task from which to retrieve the capability sets | |
194 | * @effective: The place to record the effective set | |
195 | * @inheritable: The place to record the inheritable set | |
196 | * @permitted: The place to record the permitted set | |
197 | * | |
198 | * This function retrieves the capabilities of the nominated task and returns | |
199 | * them to the caller. | |
200 | */ | |
6672efbb | 201 | int cap_capget(const struct task_struct *target, kernel_cap_t *effective, |
1d045980 | 202 | kernel_cap_t *inheritable, kernel_cap_t *permitted) |
1da177e4 | 203 | { |
c69e8d9c | 204 | const struct cred *cred; |
b6dff3ec | 205 | |
1da177e4 | 206 | /* Derived from kernel/capability.c:sys_capget. */ |
c69e8d9c DH |
207 | rcu_read_lock(); |
208 | cred = __task_cred(target); | |
b6dff3ec DH |
209 | *effective = cred->cap_effective; |
210 | *inheritable = cred->cap_inheritable; | |
211 | *permitted = cred->cap_permitted; | |
c69e8d9c | 212 | rcu_read_unlock(); |
1da177e4 LT |
213 | return 0; |
214 | } | |
215 | ||
1d045980 DH |
216 | /* |
217 | * Determine whether the inheritable capabilities are limited to the old | |
218 | * permitted set. Returns 1 if they are limited, 0 if they are not. | |
219 | */ | |
72c2d582 AM |
220 | static inline int cap_inh_is_capped(void) |
221 | { | |
1d045980 DH |
222 | /* they are so limited unless the current task has the CAP_SETPCAP |
223 | * capability | |
224 | */ | |
c4a4d603 | 225 | if (cap_capable(current_cred(), current_cred()->user_ns, |
c1a85a00 | 226 | CAP_SETPCAP, CAP_OPT_NONE) == 0) |
1d045980 | 227 | return 0; |
1d045980 | 228 | return 1; |
1209726c | 229 | } |
72c2d582 | 230 | |
1d045980 DH |
231 | /** |
232 | * cap_capset - Validate and apply proposed changes to current's capabilities | |
233 | * @new: The proposed new credentials; alterations should be made here | |
234 | * @old: The current task's current credentials | |
235 | * @effective: A pointer to the proposed new effective capabilities set | |
236 | * @inheritable: A pointer to the proposed new inheritable capabilities set | |
237 | * @permitted: A pointer to the proposed new permitted capabilities set | |
238 | * | |
239 | * This function validates and applies a proposed mass change to the current | |
240 | * process's capability sets. The changes are made to the proposed new | |
241 | * credentials, and assuming no error, will be committed by the caller of LSM. | |
242 | */ | |
d84f4f99 DH |
243 | int cap_capset(struct cred *new, |
244 | const struct cred *old, | |
245 | const kernel_cap_t *effective, | |
246 | const kernel_cap_t *inheritable, | |
247 | const kernel_cap_t *permitted) | |
1da177e4 | 248 | { |
d84f4f99 DH |
249 | if (cap_inh_is_capped() && |
250 | !cap_issubset(*inheritable, | |
251 | cap_combine(old->cap_inheritable, | |
252 | old->cap_permitted))) | |
72c2d582 | 253 | /* incapable of using this inheritable set */ |
1da177e4 | 254 | return -EPERM; |
d84f4f99 | 255 | |
3b7391de | 256 | if (!cap_issubset(*inheritable, |
d84f4f99 DH |
257 | cap_combine(old->cap_inheritable, |
258 | old->cap_bset))) | |
3b7391de SH |
259 | /* no new pI capabilities outside bounding set */ |
260 | return -EPERM; | |
1da177e4 LT |
261 | |
262 | /* verify restrictions on target's new Permitted set */ | |
d84f4f99 | 263 | if (!cap_issubset(*permitted, old->cap_permitted)) |
1da177e4 | 264 | return -EPERM; |
1da177e4 LT |
265 | |
266 | /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ | |
d84f4f99 | 267 | if (!cap_issubset(*effective, *permitted)) |
1da177e4 | 268 | return -EPERM; |
1da177e4 | 269 | |
d84f4f99 DH |
270 | new->cap_effective = *effective; |
271 | new->cap_inheritable = *inheritable; | |
272 | new->cap_permitted = *permitted; | |
58319057 AL |
273 | |
274 | /* | |
275 | * Mask off ambient bits that are no longer both permitted and | |
276 | * inheritable. | |
277 | */ | |
278 | new->cap_ambient = cap_intersect(new->cap_ambient, | |
279 | cap_intersect(*permitted, | |
280 | *inheritable)); | |
281 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
282 | return -EINVAL; | |
1da177e4 LT |
283 | return 0; |
284 | } | |
285 | ||
1d045980 DH |
286 | /** |
287 | * cap_inode_need_killpriv - Determine if inode change affects privileges | |
288 | * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV | |
289 | * | |
290 | * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV | |
291 | * affects the security markings on that inode, and if it is, should | |
ab5348c9 | 292 | * inode_killpriv() be invoked or the change rejected. |
1d045980 | 293 | * |
049ae601 | 294 | * Return: 1 if security.capability has a value, meaning inode_killpriv() |
ab5348c9 | 295 | * is required, 0 otherwise, meaning inode_killpriv() is not required. |
1d045980 | 296 | */ |
b5376771 SH |
297 | int cap_inode_need_killpriv(struct dentry *dentry) |
298 | { | |
c6f493d6 | 299 | struct inode *inode = d_backing_inode(dentry); |
b5376771 SH |
300 | int error; |
301 | ||
5d6c3191 AG |
302 | error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0); |
303 | return error > 0; | |
b5376771 SH |
304 | } |
305 | ||
1d045980 DH |
306 | /** |
307 | * cap_inode_killpriv - Erase the security markings on an inode | |
71bc356f | 308 | * |
39f60c1c | 309 | * @idmap: idmap of the mount the inode was found from |
71bc356f | 310 | * @dentry: The inode/dentry to alter |
1d045980 DH |
311 | * |
312 | * Erase the privilege-enhancing security markings on an inode. | |
313 | * | |
39f60c1c CB |
314 | * If the inode has been found through an idmapped mount the idmap of |
315 | * the vfsmount must be passed through @idmap. This function will then | |
316 | * take care to map the inode according to @idmap before checking | |
71bc356f | 317 | * permissions. On non-idmapped mounts or if permission checking is to be |
4432b507 | 318 | * performed on the raw inode simply pass @nop_mnt_idmap. |
71bc356f | 319 | * |
049ae601 | 320 | * Return: 0 if successful, -ve on error. |
1d045980 | 321 | */ |
39f60c1c | 322 | int cap_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry) |
b5376771 | 323 | { |
5d6c3191 | 324 | int error; |
b5376771 | 325 | |
39f60c1c | 326 | error = __vfs_removexattr(idmap, dentry, XATTR_NAME_CAPS); |
5d6c3191 AG |
327 | if (error == -EOPNOTSUPP) |
328 | error = 0; | |
329 | return error; | |
b5376771 SH |
330 | } |
331 | ||
b7c9b675 | 332 | static bool rootid_owns_currentns(vfsuid_t rootvfsuid) |
8db6c34f SH |
333 | { |
334 | struct user_namespace *ns; | |
b7c9b675 | 335 | kuid_t kroot; |
8db6c34f | 336 | |
b7c9b675 | 337 | if (!vfsuid_valid(rootvfsuid)) |
8db6c34f SH |
338 | return false; |
339 | ||
b7c9b675 CB |
340 | kroot = vfsuid_into_kuid(rootvfsuid); |
341 | for (ns = current_user_ns();; ns = ns->parent) { | |
8db6c34f SH |
342 | if (from_kuid(ns, kroot) == 0) |
343 | return true; | |
344 | if (ns == &init_user_ns) | |
345 | break; | |
346 | } | |
347 | ||
348 | return false; | |
349 | } | |
350 | ||
351 | static __u32 sansflags(__u32 m) | |
352 | { | |
353 | return m & ~VFS_CAP_FLAGS_EFFECTIVE; | |
354 | } | |
355 | ||
f6fbd8cb | 356 | static bool is_v2header(int size, const struct vfs_cap_data *cap) |
8db6c34f | 357 | { |
8db6c34f SH |
358 | if (size != XATTR_CAPS_SZ_2) |
359 | return false; | |
dc32b5c3 | 360 | return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_2; |
8db6c34f SH |
361 | } |
362 | ||
f6fbd8cb | 363 | static bool is_v3header(int size, const struct vfs_cap_data *cap) |
8db6c34f | 364 | { |
8db6c34f SH |
365 | if (size != XATTR_CAPS_SZ_3) |
366 | return false; | |
dc32b5c3 | 367 | return sansflags(le32_to_cpu(cap->magic_etc)) == VFS_CAP_REVISION_3; |
8db6c34f SH |
368 | } |
369 | ||
370 | /* | |
371 | * getsecurity: We are called for security.* before any attempt to read the | |
372 | * xattr from the inode itself. | |
373 | * | |
374 | * This gives us a chance to read the on-disk value and convert it. If we | |
375 | * return -EOPNOTSUPP, then vfs_getxattr() will call the i_op handler. | |
376 | * | |
377 | * Note we are not called by vfs_getxattr_alloc(), but that is only called | |
378 | * by the integrity subsystem, which really wants the unconverted values - | |
379 | * so that's good. | |
380 | */ | |
4609e1f1 | 381 | int cap_inode_getsecurity(struct mnt_idmap *idmap, |
71bc356f | 382 | struct inode *inode, const char *name, void **buffer, |
8db6c34f SH |
383 | bool alloc) |
384 | { | |
f6fbd8cb | 385 | int size; |
8db6c34f | 386 | kuid_t kroot; |
b7c9b675 | 387 | vfsuid_t vfsroot; |
f2b00be4 | 388 | u32 nsmagic, magic; |
8db6c34f SH |
389 | uid_t root, mappedroot; |
390 | char *tmpbuf = NULL; | |
391 | struct vfs_cap_data *cap; | |
f2b00be4 | 392 | struct vfs_ns_cap_data *nscap = NULL; |
8db6c34f SH |
393 | struct dentry *dentry; |
394 | struct user_namespace *fs_ns; | |
395 | ||
396 | if (strcmp(name, "capability") != 0) | |
397 | return -EOPNOTSUPP; | |
398 | ||
355139a8 | 399 | dentry = d_find_any_alias(inode); |
8db6c34f SH |
400 | if (!dentry) |
401 | return -EINVAL; | |
4609e1f1 | 402 | size = vfs_getxattr_alloc(idmap, dentry, XATTR_NAME_CAPS, &tmpbuf, |
f6fbd8cb | 403 | sizeof(struct vfs_ns_cap_data), GFP_NOFS); |
8db6c34f | 404 | dput(dentry); |
f6fbd8cb PM |
405 | /* gcc11 complains if we don't check for !tmpbuf */ |
406 | if (size < 0 || !tmpbuf) | |
8cf0a1bc | 407 | goto out_free; |
8db6c34f SH |
408 | |
409 | fs_ns = inode->i_sb->s_user_ns; | |
410 | cap = (struct vfs_cap_data *) tmpbuf; | |
f6fbd8cb | 411 | if (is_v2header(size, cap)) { |
f2b00be4 | 412 | root = 0; |
f6fbd8cb | 413 | } else if (is_v3header(size, cap)) { |
f2b00be4 MS |
414 | nscap = (struct vfs_ns_cap_data *) tmpbuf; |
415 | root = le32_to_cpu(nscap->rootid); | |
416 | } else { | |
417 | size = -EINVAL; | |
418 | goto out_free; | |
8db6c34f SH |
419 | } |
420 | ||
8db6c34f SH |
421 | kroot = make_kuid(fs_ns, root); |
422 | ||
71bc356f | 423 | /* If this is an idmapped mount shift the kuid. */ |
4d7ca409 | 424 | vfsroot = make_vfsuid(idmap, fs_ns, kroot); |
71bc356f | 425 | |
8db6c34f SH |
426 | /* If the root kuid maps to a valid uid in current ns, then return |
427 | * this as a nscap. */ | |
b7c9b675 | 428 | mappedroot = from_kuid(current_user_ns(), vfsuid_into_kuid(vfsroot)); |
8db6c34f | 429 | if (mappedroot != (uid_t)-1 && mappedroot != (uid_t)0) { |
f2b00be4 | 430 | size = sizeof(struct vfs_ns_cap_data); |
8db6c34f | 431 | if (alloc) { |
f2b00be4 MS |
432 | if (!nscap) { |
433 | /* v2 -> v3 conversion */ | |
434 | nscap = kzalloc(size, GFP_ATOMIC); | |
435 | if (!nscap) { | |
436 | size = -ENOMEM; | |
437 | goto out_free; | |
438 | } | |
439 | nsmagic = VFS_CAP_REVISION_3; | |
440 | magic = le32_to_cpu(cap->magic_etc); | |
441 | if (magic & VFS_CAP_FLAGS_EFFECTIVE) | |
442 | nsmagic |= VFS_CAP_FLAGS_EFFECTIVE; | |
443 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); | |
444 | nscap->magic_etc = cpu_to_le32(nsmagic); | |
445 | } else { | |
446 | /* use allocated v3 buffer */ | |
447 | tmpbuf = NULL; | |
448 | } | |
8db6c34f | 449 | nscap->rootid = cpu_to_le32(mappedroot); |
f2b00be4 MS |
450 | *buffer = nscap; |
451 | } | |
452 | goto out_free; | |
8db6c34f SH |
453 | } |
454 | ||
b7c9b675 | 455 | if (!rootid_owns_currentns(vfsroot)) { |
f2b00be4 MS |
456 | size = -EOVERFLOW; |
457 | goto out_free; | |
8db6c34f SH |
458 | } |
459 | ||
460 | /* This comes from a parent namespace. Return as a v2 capability */ | |
461 | size = sizeof(struct vfs_cap_data); | |
462 | if (alloc) { | |
f2b00be4 MS |
463 | if (nscap) { |
464 | /* v3 -> v2 conversion */ | |
465 | cap = kzalloc(size, GFP_ATOMIC); | |
466 | if (!cap) { | |
467 | size = -ENOMEM; | |
468 | goto out_free; | |
469 | } | |
8db6c34f SH |
470 | magic = VFS_CAP_REVISION_2; |
471 | nsmagic = le32_to_cpu(nscap->magic_etc); | |
472 | if (nsmagic & VFS_CAP_FLAGS_EFFECTIVE) | |
473 | magic |= VFS_CAP_FLAGS_EFFECTIVE; | |
474 | memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); | |
475 | cap->magic_etc = cpu_to_le32(magic); | |
1f578172 | 476 | } else { |
f2b00be4 MS |
477 | /* use unconverted v2 */ |
478 | tmpbuf = NULL; | |
8db6c34f | 479 | } |
f2b00be4 | 480 | *buffer = cap; |
8db6c34f | 481 | } |
f2b00be4 | 482 | out_free: |
8db6c34f SH |
483 | kfree(tmpbuf); |
484 | return size; | |
485 | } | |
486 | ||
e65ce2a5 CB |
487 | /** |
488 | * rootid_from_xattr - translate root uid of vfs caps | |
489 | * | |
490 | * @value: vfs caps value which may be modified by this function | |
491 | * @size: size of @ivalue | |
492 | * @task_ns: user namespace of the caller | |
e65ce2a5 | 493 | */ |
b7c9b675 CB |
494 | static vfsuid_t rootid_from_xattr(const void *value, size_t size, |
495 | struct user_namespace *task_ns) | |
8db6c34f SH |
496 | { |
497 | const struct vfs_ns_cap_data *nscap = value; | |
498 | uid_t rootid = 0; | |
499 | ||
500 | if (size == XATTR_CAPS_SZ_3) | |
501 | rootid = le32_to_cpu(nscap->rootid); | |
502 | ||
b7c9b675 | 503 | return VFSUIDT_INIT(make_kuid(task_ns, rootid)); |
8db6c34f SH |
504 | } |
505 | ||
dc32b5c3 | 506 | static bool validheader(size_t size, const struct vfs_cap_data *cap) |
8db6c34f | 507 | { |
dc32b5c3 | 508 | return is_v2header(size, cap) || is_v3header(size, cap); |
8db6c34f SH |
509 | } |
510 | ||
e65ce2a5 CB |
511 | /** |
512 | * cap_convert_nscap - check vfs caps | |
513 | * | |
39f60c1c | 514 | * @idmap: idmap of the mount the inode was found from |
e65ce2a5 CB |
515 | * @dentry: used to retrieve inode to check permissions on |
516 | * @ivalue: vfs caps value which may be modified by this function | |
517 | * @size: size of @ivalue | |
518 | * | |
8db6c34f SH |
519 | * User requested a write of security.capability. If needed, update the |
520 | * xattr to change from v2 to v3, or to fixup the v3 rootid. | |
521 | * | |
39f60c1c CB |
522 | * If the inode has been found through an idmapped mount the idmap of |
523 | * the vfsmount must be passed through @idmap. This function will then | |
524 | * take care to map the inode according to @idmap before checking | |
e65ce2a5 | 525 | * permissions. On non-idmapped mounts or if permission checking is to be |
4432b507 | 526 | * performed on the raw inode simply pass @nop_mnt_idmap. |
e65ce2a5 | 527 | * |
049ae601 | 528 | * Return: On success, return the new size; on error, return < 0. |
8db6c34f | 529 | */ |
39f60c1c | 530 | int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry, |
e65ce2a5 | 531 | const void **ivalue, size_t size) |
8db6c34f SH |
532 | { |
533 | struct vfs_ns_cap_data *nscap; | |
534 | uid_t nsrootid; | |
535 | const struct vfs_cap_data *cap = *ivalue; | |
536 | __u32 magic, nsmagic; | |
537 | struct inode *inode = d_backing_inode(dentry); | |
538 | struct user_namespace *task_ns = current_user_ns(), | |
3b0c2d3e | 539 | *fs_ns = inode->i_sb->s_user_ns; |
8db6c34f | 540 | kuid_t rootid; |
b7c9b675 | 541 | vfsuid_t vfsrootid; |
8db6c34f SH |
542 | size_t newsize; |
543 | ||
544 | if (!*ivalue) | |
545 | return -EINVAL; | |
dc32b5c3 | 546 | if (!validheader(size, cap)) |
8db6c34f | 547 | return -EINVAL; |
9452e93e | 548 | if (!capable_wrt_inode_uidgid(idmap, inode, CAP_SETFCAP)) |
8db6c34f | 549 | return -EPERM; |
39f60c1c | 550 | if (size == XATTR_CAPS_SZ_2 && (idmap == &nop_mnt_idmap)) |
8db6c34f SH |
551 | if (ns_capable(inode->i_sb->s_user_ns, CAP_SETFCAP)) |
552 | /* user is privileged, just write the v2 */ | |
553 | return size; | |
554 | ||
b7c9b675 CB |
555 | vfsrootid = rootid_from_xattr(*ivalue, size, task_ns); |
556 | if (!vfsuid_valid(vfsrootid)) | |
557 | return -EINVAL; | |
558 | ||
4d7ca409 | 559 | rootid = from_vfsuid(idmap, fs_ns, vfsrootid); |
8db6c34f SH |
560 | if (!uid_valid(rootid)) |
561 | return -EINVAL; | |
562 | ||
563 | nsrootid = from_kuid(fs_ns, rootid); | |
564 | if (nsrootid == -1) | |
565 | return -EINVAL; | |
566 | ||
567 | newsize = sizeof(struct vfs_ns_cap_data); | |
568 | nscap = kmalloc(newsize, GFP_ATOMIC); | |
569 | if (!nscap) | |
570 | return -ENOMEM; | |
571 | nscap->rootid = cpu_to_le32(nsrootid); | |
572 | nsmagic = VFS_CAP_REVISION_3; | |
573 | magic = le32_to_cpu(cap->magic_etc); | |
574 | if (magic & VFS_CAP_FLAGS_EFFECTIVE) | |
575 | nsmagic |= VFS_CAP_FLAGS_EFFECTIVE; | |
576 | nscap->magic_etc = cpu_to_le32(nsmagic); | |
577 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); | |
578 | ||
8db6c34f SH |
579 | *ivalue = nscap; |
580 | return newsize; | |
581 | } | |
582 | ||
1d045980 DH |
583 | /* |
584 | * Calculate the new process capability sets from the capability sets attached | |
585 | * to a file. | |
586 | */ | |
c0b00441 | 587 | static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, |
a6f76f23 | 588 | struct linux_binprm *bprm, |
4d49f671 | 589 | bool *effective, |
fc7eadf7 | 590 | bool *has_fcap) |
b5376771 | 591 | { |
a6f76f23 | 592 | struct cred *new = bprm->cred; |
c0b00441 EP |
593 | int ret = 0; |
594 | ||
595 | if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) | |
a6f76f23 | 596 | *effective = true; |
c0b00441 | 597 | |
4d49f671 | 598 | if (caps->magic_etc & VFS_CAP_REVISION_MASK) |
fc7eadf7 | 599 | *has_fcap = true; |
4d49f671 | 600 | |
f122a08b LT |
601 | /* |
602 | * pP' = (X & fP) | (pI & fI) | |
603 | * The addition of pA' is handled later. | |
604 | */ | |
605 | new->cap_permitted.val = | |
606 | (new->cap_bset.val & caps->permitted.val) | | |
607 | (new->cap_inheritable.val & caps->inheritable.val); | |
c0b00441 | 608 | |
f122a08b LT |
609 | if (caps->permitted.val & ~new->cap_permitted.val) |
610 | /* insufficient to execute correctly */ | |
611 | ret = -EPERM; | |
c0b00441 EP |
612 | |
613 | /* | |
614 | * For legacy apps, with no internal support for recognizing they | |
615 | * do not have enough capabilities, we return an error if they are | |
616 | * missing some "forced" (aka file-permitted) capabilities. | |
617 | */ | |
a6f76f23 | 618 | return *effective ? ret : 0; |
c0b00441 EP |
619 | } |
620 | ||
71bc356f CB |
621 | /** |
622 | * get_vfs_caps_from_disk - retrieve vfs caps from disk | |
623 | * | |
39f60c1c | 624 | * @idmap: idmap of the mount the inode was found from |
71bc356f CB |
625 | * @dentry: dentry from which @inode is retrieved |
626 | * @cpu_caps: vfs capabilities | |
627 | * | |
1d045980 | 628 | * Extract the on-exec-apply capability sets for an executable file. |
71bc356f | 629 | * |
39f60c1c CB |
630 | * If the inode has been found through an idmapped mount the idmap of |
631 | * the vfsmount must be passed through @idmap. This function will then | |
632 | * take care to map the inode according to @idmap before checking | |
71bc356f | 633 | * permissions. On non-idmapped mounts or if permission checking is to be |
4432b507 | 634 | * performed on the raw inode simply pass @nop_mnt_idmap. |
1d045980 | 635 | */ |
39f60c1c | 636 | int get_vfs_caps_from_disk(struct mnt_idmap *idmap, |
71bc356f CB |
637 | const struct dentry *dentry, |
638 | struct cpu_vfs_cap_data *cpu_caps) | |
c0b00441 | 639 | { |
c6f493d6 | 640 | struct inode *inode = d_backing_inode(dentry); |
b5376771 | 641 | __u32 magic_etc; |
c0b00441 | 642 | int size; |
8db6c34f SH |
643 | struct vfs_ns_cap_data data, *nscaps = &data; |
644 | struct vfs_cap_data *caps = (struct vfs_cap_data *) &data; | |
645 | kuid_t rootkuid; | |
b7c9b675 | 646 | vfsuid_t rootvfsuid; |
76ba89c7 | 647 | struct user_namespace *fs_ns; |
c0b00441 EP |
648 | |
649 | memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); | |
650 | ||
5d6c3191 | 651 | if (!inode) |
c0b00441 EP |
652 | return -ENODATA; |
653 | ||
76ba89c7 | 654 | fs_ns = inode->i_sb->s_user_ns; |
5d6c3191 | 655 | size = __vfs_getxattr((struct dentry *)dentry, inode, |
8db6c34f | 656 | XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ); |
a6f76f23 | 657 | if (size == -ENODATA || size == -EOPNOTSUPP) |
c0b00441 EP |
658 | /* no data, that's ok */ |
659 | return -ENODATA; | |
8db6c34f | 660 | |
c0b00441 EP |
661 | if (size < 0) |
662 | return size; | |
b5376771 | 663 | |
e338d263 | 664 | if (size < sizeof(magic_etc)) |
b5376771 SH |
665 | return -EINVAL; |
666 | ||
8db6c34f | 667 | cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps->magic_etc); |
b5376771 | 668 | |
8db6c34f | 669 | rootkuid = make_kuid(fs_ns, 0); |
a6f76f23 | 670 | switch (magic_etc & VFS_CAP_REVISION_MASK) { |
e338d263 AM |
671 | case VFS_CAP_REVISION_1: |
672 | if (size != XATTR_CAPS_SZ_1) | |
673 | return -EINVAL; | |
e338d263 AM |
674 | break; |
675 | case VFS_CAP_REVISION_2: | |
676 | if (size != XATTR_CAPS_SZ_2) | |
677 | return -EINVAL; | |
e338d263 | 678 | break; |
8db6c34f SH |
679 | case VFS_CAP_REVISION_3: |
680 | if (size != XATTR_CAPS_SZ_3) | |
681 | return -EINVAL; | |
8db6c34f SH |
682 | rootkuid = make_kuid(fs_ns, le32_to_cpu(nscaps->rootid)); |
683 | break; | |
684 | ||
b5376771 SH |
685 | default: |
686 | return -EINVAL; | |
687 | } | |
b7c9b675 | 688 | |
4d7ca409 | 689 | rootvfsuid = make_vfsuid(idmap, fs_ns, rootkuid); |
b7c9b675 CB |
690 | if (!vfsuid_valid(rootvfsuid)) |
691 | return -ENODATA; | |
692 | ||
8db6c34f SH |
693 | /* Limit the caps to the mounter of the filesystem |
694 | * or the more limited uid specified in the xattr. | |
695 | */ | |
b7c9b675 | 696 | if (!rootid_owns_currentns(rootvfsuid)) |
8db6c34f | 697 | return -ENODATA; |
e338d263 | 698 | |
f122a08b LT |
699 | cpu_caps->permitted.val = le32_to_cpu(caps->data[0].permitted); |
700 | cpu_caps->inheritable.val = le32_to_cpu(caps->data[0].inheritable); | |
701 | ||
702 | /* | |
703 | * Rev1 had just a single 32-bit word, later expanded | |
704 | * to a second one for the high bits | |
705 | */ | |
706 | if ((magic_etc & VFS_CAP_REVISION_MASK) != VFS_CAP_REVISION_1) { | |
707 | cpu_caps->permitted.val += (u64)le32_to_cpu(caps->data[1].permitted) << 32; | |
708 | cpu_caps->inheritable.val += (u64)le32_to_cpu(caps->data[1].inheritable) << 32; | |
e338d263 | 709 | } |
a6f76f23 | 710 | |
f122a08b LT |
711 | cpu_caps->permitted.val &= CAP_VALID_MASK; |
712 | cpu_caps->inheritable.val &= CAP_VALID_MASK; | |
7d8b6c63 | 713 | |
b7c9b675 | 714 | cpu_caps->rootid = vfsuid_into_kuid(rootvfsuid); |
2fec30e2 | 715 | |
c0b00441 | 716 | return 0; |
b5376771 SH |
717 | } |
718 | ||
1d045980 DH |
719 | /* |
720 | * Attempt to get the on-exec apply capability sets for an executable file from | |
721 | * its xattrs and, if present, apply them to the proposed credentials being | |
722 | * constructed by execve(). | |
723 | */ | |
4a00c673 | 724 | static int get_file_caps(struct linux_binprm *bprm, const struct file *file, |
56305aa9 | 725 | bool *effective, bool *has_fcap) |
b5376771 | 726 | { |
b5376771 | 727 | int rc = 0; |
c0b00441 | 728 | struct cpu_vfs_cap_data vcaps; |
b5376771 | 729 | |
ee67ae7e | 730 | cap_clear(bprm->cred->cap_permitted); |
3318a386 | 731 | |
1f29fae2 SH |
732 | if (!file_caps_enabled) |
733 | return 0; | |
734 | ||
56305aa9 | 735 | if (!mnt_may_suid(file->f_path.mnt)) |
b5376771 | 736 | return 0; |
380cf5ba AL |
737 | |
738 | /* | |
739 | * This check is redundant with mnt_may_suid() but is kept to make | |
740 | * explicit that capability bits are limited to s_user_ns and its | |
741 | * descendants. | |
742 | */ | |
56305aa9 | 743 | if (!current_in_userns(file->f_path.mnt->mnt_sb->s_user_ns)) |
d07b846f | 744 | return 0; |
b5376771 | 745 | |
39f60c1c | 746 | rc = get_vfs_caps_from_disk(file_mnt_idmap(file), |
71bc356f | 747 | file->f_path.dentry, &vcaps); |
c0b00441 EP |
748 | if (rc < 0) { |
749 | if (rc == -EINVAL) | |
8db6c34f SH |
750 | printk(KERN_NOTICE "Invalid argument reading file caps for %s\n", |
751 | bprm->filename); | |
c0b00441 EP |
752 | else if (rc == -ENODATA) |
753 | rc = 0; | |
b5376771 SH |
754 | goto out; |
755 | } | |
b5376771 | 756 | |
fc7eadf7 | 757 | rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_fcap); |
b5376771 SH |
758 | |
759 | out: | |
b5376771 | 760 | if (rc) |
ee67ae7e | 761 | cap_clear(bprm->cred->cap_permitted); |
b5376771 SH |
762 | |
763 | return rc; | |
764 | } | |
765 | ||
9304b46c RGB |
766 | static inline bool root_privileged(void) { return !issecure(SECURE_NOROOT); } |
767 | ||
81a6a012 RGB |
768 | static inline bool __is_real(kuid_t uid, struct cred *cred) |
769 | { return uid_eq(cred->uid, uid); } | |
770 | ||
771 | static inline bool __is_eff(kuid_t uid, struct cred *cred) | |
772 | { return uid_eq(cred->euid, uid); } | |
773 | ||
774 | static inline bool __is_suid(kuid_t uid, struct cred *cred) | |
775 | { return !__is_real(uid, cred) && __is_eff(uid, cred); } | |
776 | ||
db1a8922 RGB |
777 | /* |
778 | * handle_privileged_root - Handle case of privileged root | |
779 | * @bprm: The execution parameters, including the proposed creds | |
780 | * @has_fcap: Are any file capabilities set? | |
781 | * @effective: Do we have effective root privilege? | |
782 | * @root_uid: This namespace' root UID WRT initial USER namespace | |
783 | * | |
784 | * Handle the case where root is privileged and hasn't been neutered by | |
785 | * SECURE_NOROOT. If file capabilities are set, they won't be combined with | |
786 | * set UID root and nothing is changed. If we are root, cap_permitted is | |
787 | * updated. If we have become set UID root, the effective bit is set. | |
788 | */ | |
fc7eadf7 | 789 | static void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, |
db1a8922 RGB |
790 | bool *effective, kuid_t root_uid) |
791 | { | |
792 | const struct cred *old = current_cred(); | |
793 | struct cred *new = bprm->cred; | |
794 | ||
9304b46c | 795 | if (!root_privileged()) |
db1a8922 RGB |
796 | return; |
797 | /* | |
798 | * If the legacy file capability is set, then don't set privs | |
799 | * for a setuid root binary run by a non-root user. Do set it | |
800 | * for a root user just to cause least surprise to an admin. | |
801 | */ | |
81a6a012 | 802 | if (has_fcap && __is_suid(root_uid, new)) { |
db1a8922 RGB |
803 | warn_setuid_and_fcaps_mixed(bprm->filename); |
804 | return; | |
805 | } | |
806 | /* | |
807 | * To support inheritance of root-permissions and suid-root | |
808 | * executables under compatibility mode, we override the | |
809 | * capability sets for the file. | |
810 | */ | |
81a6a012 | 811 | if (__is_eff(root_uid, new) || __is_real(root_uid, new)) { |
db1a8922 RGB |
812 | /* pP' = (cap_bset & ~0) | (pI & ~0) */ |
813 | new->cap_permitted = cap_combine(old->cap_bset, | |
814 | old->cap_inheritable); | |
815 | } | |
816 | /* | |
817 | * If only the real uid is 0, we do not set the effective bit. | |
818 | */ | |
81a6a012 | 819 | if (__is_eff(root_uid, new)) |
db1a8922 RGB |
820 | *effective = true; |
821 | } | |
822 | ||
4c7e715f RGB |
823 | #define __cap_gained(field, target, source) \ |
824 | !cap_issubset(target->cap_##field, source->cap_##field) | |
825 | #define __cap_grew(target, source, cred) \ | |
826 | !cap_issubset(cred->cap_##target, cred->cap_##source) | |
827 | #define __cap_full(field, cred) \ | |
828 | cap_issubset(CAP_FULL_SET, cred->cap_##field) | |
81a6a012 RGB |
829 | |
830 | static inline bool __is_setuid(struct cred *new, const struct cred *old) | |
831 | { return !uid_eq(new->euid, old->uid); } | |
832 | ||
833 | static inline bool __is_setgid(struct cred *new, const struct cred *old) | |
834 | { return !gid_eq(new->egid, old->gid); } | |
835 | ||
9fbc2c79 | 836 | /* |
dbbbe110 | 837 | * 1) Audit candidate if current->cap_effective is set |
9fbc2c79 RGB |
838 | * |
839 | * We do not bother to audit if 3 things are true: | |
840 | * 1) cap_effective has all caps | |
588fb2c7 | 841 | * 2) we became root *OR* are were already root |
9fbc2c79 RGB |
842 | * 3) root is supposed to have all caps (SECURE_NOROOT) |
843 | * Since this is just a normal root execing a process. | |
844 | * | |
845 | * Number 1 above might fail if you don't have a full bset, but I think | |
846 | * that is interesting information to audit. | |
dbbbe110 RGB |
847 | * |
848 | * A number of other conditions require logging: | |
849 | * 2) something prevented setuid root getting all caps | |
850 | * 3) non-setuid root gets fcaps | |
851 | * 4) non-setuid root gets ambient | |
9fbc2c79 | 852 | */ |
dbbbe110 RGB |
853 | static inline bool nonroot_raised_pE(struct cred *new, const struct cred *old, |
854 | kuid_t root, bool has_fcap) | |
9fbc2c79 RGB |
855 | { |
856 | bool ret = false; | |
857 | ||
dbbbe110 RGB |
858 | if ((__cap_grew(effective, ambient, new) && |
859 | !(__cap_full(effective, new) && | |
860 | (__is_eff(root, new) || __is_real(root, new)) && | |
861 | root_privileged())) || | |
862 | (root_privileged() && | |
863 | __is_suid(root, new) && | |
864 | !__cap_full(effective, new)) || | |
865 | (!__is_setuid(new, old) && | |
866 | ((has_fcap && | |
867 | __cap_gained(permitted, new, old)) || | |
868 | __cap_gained(ambient, new, old)))) | |
869 | ||
02ebbaf4 | 870 | ret = true; |
dbbbe110 | 871 | |
9fbc2c79 RGB |
872 | return ret; |
873 | } | |
874 | ||
1d045980 | 875 | /** |
56305aa9 | 876 | * cap_bprm_creds_from_file - Set up the proposed credentials for execve(). |
1d045980 | 877 | * @bprm: The execution parameters, including the proposed creds |
56305aa9 | 878 | * @file: The file to pull the credentials from |
1d045980 DH |
879 | * |
880 | * Set up the proposed credentials for a new execution context being | |
881 | * constructed by execve(). The proposed creds in @bprm->cred is altered, | |
049ae601 RD |
882 | * which won't take effect immediately. |
883 | * | |
884 | * Return: 0 if successful, -ve on error. | |
a6f76f23 | 885 | */ |
4a00c673 | 886 | int cap_bprm_creds_from_file(struct linux_binprm *bprm, const struct file *file) |
1da177e4 | 887 | { |
56305aa9 | 888 | /* Process setpcap binaries and capabilities for uid 0 */ |
a6f76f23 DH |
889 | const struct cred *old = current_cred(); |
890 | struct cred *new = bprm->cred; | |
fc7eadf7 | 891 | bool effective = false, has_fcap = false, is_setid; |
b5376771 | 892 | int ret; |
18815a18 | 893 | kuid_t root_uid; |
1da177e4 | 894 | |
58319057 AL |
895 | if (WARN_ON(!cap_ambient_invariant_ok(old))) |
896 | return -EPERM; | |
897 | ||
56305aa9 | 898 | ret = get_file_caps(bprm, file, &effective, &has_fcap); |
a6f76f23 DH |
899 | if (ret < 0) |
900 | return ret; | |
1da177e4 | 901 | |
18815a18 EB |
902 | root_uid = make_kuid(new->user_ns, 0); |
903 | ||
fc7eadf7 | 904 | handle_privileged_root(bprm, has_fcap, &effective, root_uid); |
b5376771 | 905 | |
d52fc5dd | 906 | /* if we have fs caps, clear dangerous personality flags */ |
4c7e715f | 907 | if (__cap_gained(permitted, new, old)) |
56305aa9 | 908 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
d52fc5dd | 909 | |
a6f76f23 | 910 | /* Don't let someone trace a set[ug]id/setpcap binary with the revised |
259e5e6c AL |
911 | * credentials unless they have the appropriate permit. |
912 | * | |
913 | * In addition, if NO_NEW_PRIVS, then ensure we get no new privs. | |
a6f76f23 | 914 | */ |
81a6a012 | 915 | is_setid = __is_setuid(new, old) || __is_setgid(new, old); |
58319057 | 916 | |
4c7e715f | 917 | if ((is_setid || __cap_gained(permitted, new, old)) && |
9227dd2a | 918 | ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) || |
20523132 | 919 | !ptracer_capable(current, new->user_ns))) { |
a6f76f23 | 920 | /* downgrade; they get no more than they had, and maybe less */ |
70169420 | 921 | if (!ns_capable(new->user_ns, CAP_SETUID) || |
259e5e6c | 922 | (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) { |
a6f76f23 DH |
923 | new->euid = new->uid; |
924 | new->egid = new->gid; | |
1da177e4 | 925 | } |
b3a222e5 SH |
926 | new->cap_permitted = cap_intersect(new->cap_permitted, |
927 | old->cap_permitted); | |
1da177e4 LT |
928 | } |
929 | ||
a6f76f23 DH |
930 | new->suid = new->fsuid = new->euid; |
931 | new->sgid = new->fsgid = new->egid; | |
1da177e4 | 932 | |
58319057 | 933 | /* File caps or setid cancels ambient. */ |
fc7eadf7 | 934 | if (has_fcap || is_setid) |
58319057 AL |
935 | cap_clear(new->cap_ambient); |
936 | ||
937 | /* | |
938 | * Now that we've computed pA', update pP' to give: | |
939 | * pP' = (X & fP) | (pI & fI) | pA' | |
940 | */ | |
941 | new->cap_permitted = cap_combine(new->cap_permitted, new->cap_ambient); | |
942 | ||
943 | /* | |
944 | * Set pE' = (fE ? pP' : pA'). Because pA' is zero if fE is set, | |
945 | * this is the same as pE' = (fE ? pP' : 0) | pA'. | |
946 | */ | |
4bf2ea77 EP |
947 | if (effective) |
948 | new->cap_effective = new->cap_permitted; | |
949 | else | |
58319057 AL |
950 | new->cap_effective = new->cap_ambient; |
951 | ||
952 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
953 | return -EPERM; | |
954 | ||
dbbbe110 | 955 | if (nonroot_raised_pE(new, old, root_uid, has_fcap)) { |
9fbc2c79 RGB |
956 | ret = audit_log_bprm_fcaps(bprm, new, old); |
957 | if (ret < 0) | |
958 | return ret; | |
3fc689e9 | 959 | } |
1da177e4 | 960 | |
d84f4f99 | 961 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
58319057 AL |
962 | |
963 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
964 | return -EPERM; | |
965 | ||
46d98eb4 | 966 | /* Check for privilege-elevated exec. */ |
02ebbaf4 RGB |
967 | if (is_setid || |
968 | (!__is_real(root_uid, new) && | |
969 | (effective || | |
970 | __cap_grew(permitted, ambient, new)))) | |
56305aa9 | 971 | bprm->secureexec = 1; |
b5376771 | 972 | |
ee67ae7e | 973 | return 0; |
1da177e4 LT |
974 | } |
975 | ||
1d045980 DH |
976 | /** |
977 | * cap_inode_setxattr - Determine whether an xattr may be altered | |
978 | * @dentry: The inode/dentry being altered | |
979 | * @name: The name of the xattr to be changed | |
980 | * @value: The value that the xattr will be changed to | |
981 | * @size: The size of value | |
982 | * @flags: The replacement flag | |
983 | * | |
984 | * Determine whether an xattr may be altered or set on an inode, returning 0 if | |
985 | * permission is granted, -ve if denied. | |
986 | * | |
987 | * This is used to make sure security xattrs don't get updated or set by those | |
988 | * who aren't privileged to do so. | |
989 | */ | |
8f0cfa52 DH |
990 | int cap_inode_setxattr(struct dentry *dentry, const char *name, |
991 | const void *value, size_t size, int flags) | |
1da177e4 | 992 | { |
b1d749c5 EB |
993 | struct user_namespace *user_ns = dentry->d_sb->s_user_ns; |
994 | ||
8db6c34f SH |
995 | /* Ignore non-security xattrs */ |
996 | if (strncmp(name, XATTR_SECURITY_PREFIX, | |
c5eaab1d | 997 | XATTR_SECURITY_PREFIX_LEN) != 0) |
8db6c34f SH |
998 | return 0; |
999 | ||
1000 | /* | |
1001 | * For XATTR_NAME_CAPS the check will be done in | |
1002 | * cap_convert_nscap(), called by setxattr() | |
1003 | */ | |
1004 | if (strcmp(name, XATTR_NAME_CAPS) == 0) | |
b5376771 | 1005 | return 0; |
1d045980 | 1006 | |
b1d749c5 | 1007 | if (!ns_capable(user_ns, CAP_SYS_ADMIN)) |
1da177e4 LT |
1008 | return -EPERM; |
1009 | return 0; | |
1010 | } | |
1011 | ||
1d045980 DH |
1012 | /** |
1013 | * cap_inode_removexattr - Determine whether an xattr may be removed | |
71bc356f | 1014 | * |
39f60c1c | 1015 | * @idmap: idmap of the mount the inode was found from |
71bc356f CB |
1016 | * @dentry: The inode/dentry being altered |
1017 | * @name: The name of the xattr to be changed | |
1d045980 DH |
1018 | * |
1019 | * Determine whether an xattr may be removed from an inode, returning 0 if | |
1020 | * permission is granted, -ve if denied. | |
1021 | * | |
39f60c1c CB |
1022 | * If the inode has been found through an idmapped mount the idmap of |
1023 | * the vfsmount must be passed through @idmap. This function will then | |
1024 | * take care to map the inode according to @idmap before checking | |
71bc356f | 1025 | * permissions. On non-idmapped mounts or if permission checking is to be |
39f60c1c | 1026 | * performed on the raw inode simply pass @nop_mnt_idmap. |
71bc356f | 1027 | * |
1d045980 DH |
1028 | * This is used to make sure security xattrs don't get removed by those who |
1029 | * aren't privileged to remove them. | |
1030 | */ | |
39f60c1c | 1031 | int cap_inode_removexattr(struct mnt_idmap *idmap, |
71bc356f | 1032 | struct dentry *dentry, const char *name) |
1da177e4 | 1033 | { |
b1d749c5 EB |
1034 | struct user_namespace *user_ns = dentry->d_sb->s_user_ns; |
1035 | ||
8db6c34f SH |
1036 | /* Ignore non-security xattrs */ |
1037 | if (strncmp(name, XATTR_SECURITY_PREFIX, | |
c5eaab1d | 1038 | XATTR_SECURITY_PREFIX_LEN) != 0) |
8db6c34f SH |
1039 | return 0; |
1040 | ||
1041 | if (strcmp(name, XATTR_NAME_CAPS) == 0) { | |
1042 | /* security.capability gets namespaced */ | |
1043 | struct inode *inode = d_backing_inode(dentry); | |
1044 | if (!inode) | |
1045 | return -EINVAL; | |
9452e93e | 1046 | if (!capable_wrt_inode_uidgid(idmap, inode, CAP_SETFCAP)) |
b5376771 SH |
1047 | return -EPERM; |
1048 | return 0; | |
1d045980 DH |
1049 | } |
1050 | ||
b1d749c5 | 1051 | if (!ns_capable(user_ns, CAP_SYS_ADMIN)) |
1da177e4 LT |
1052 | return -EPERM; |
1053 | return 0; | |
1054 | } | |
1055 | ||
a6f76f23 | 1056 | /* |
1da177e4 LT |
1057 | * cap_emulate_setxuid() fixes the effective / permitted capabilities of |
1058 | * a process after a call to setuid, setreuid, or setresuid. | |
1059 | * | |
1060 | * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of | |
1061 | * {r,e,s}uid != 0, the permitted and effective capabilities are | |
1062 | * cleared. | |
1063 | * | |
1064 | * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective | |
1065 | * capabilities of the process are cleared. | |
1066 | * | |
1067 | * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective | |
1068 | * capabilities are set to the permitted capabilities. | |
1069 | * | |
a6f76f23 | 1070 | * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should |
1da177e4 LT |
1071 | * never happen. |
1072 | * | |
a6f76f23 | 1073 | * -astor |
1da177e4 LT |
1074 | * |
1075 | * cevans - New behaviour, Oct '99 | |
1076 | * A process may, via prctl(), elect to keep its capabilities when it | |
1077 | * calls setuid() and switches away from uid==0. Both permitted and | |
1078 | * effective sets will be retained. | |
1079 | * Without this change, it was impossible for a daemon to drop only some | |
1080 | * of its privilege. The call to setuid(!=0) would drop all privileges! | |
1081 | * Keeping uid 0 is not an option because uid 0 owns too many vital | |
1082 | * files.. | |
1083 | * Thanks to Olaf Kirch and Peter Benie for spotting this. | |
1084 | */ | |
d84f4f99 | 1085 | static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old) |
1da177e4 | 1086 | { |
18815a18 EB |
1087 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
1088 | ||
1089 | if ((uid_eq(old->uid, root_uid) || | |
1090 | uid_eq(old->euid, root_uid) || | |
1091 | uid_eq(old->suid, root_uid)) && | |
1092 | (!uid_eq(new->uid, root_uid) && | |
1093 | !uid_eq(new->euid, root_uid) && | |
58319057 AL |
1094 | !uid_eq(new->suid, root_uid))) { |
1095 | if (!issecure(SECURE_KEEP_CAPS)) { | |
1096 | cap_clear(new->cap_permitted); | |
1097 | cap_clear(new->cap_effective); | |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * Pre-ambient programs expect setresuid to nonroot followed | |
1102 | * by exec to drop capabilities. We should make sure that | |
1103 | * this remains the case. | |
1104 | */ | |
1105 | cap_clear(new->cap_ambient); | |
1da177e4 | 1106 | } |
18815a18 | 1107 | if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid)) |
d84f4f99 | 1108 | cap_clear(new->cap_effective); |
18815a18 | 1109 | if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid)) |
d84f4f99 | 1110 | new->cap_effective = new->cap_permitted; |
1da177e4 LT |
1111 | } |
1112 | ||
1d045980 DH |
1113 | /** |
1114 | * cap_task_fix_setuid - Fix up the results of setuid() call | |
1115 | * @new: The proposed credentials | |
1116 | * @old: The current task's current credentials | |
1117 | * @flags: Indications of what has changed | |
1118 | * | |
1119 | * Fix up the results of setuid() call before the credential changes are | |
049ae601 RD |
1120 | * actually applied. |
1121 | * | |
1122 | * Return: 0 to grant the changes, -ve to deny them. | |
1d045980 | 1123 | */ |
d84f4f99 | 1124 | int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) |
1da177e4 LT |
1125 | { |
1126 | switch (flags) { | |
1127 | case LSM_SETID_RE: | |
1128 | case LSM_SETID_ID: | |
1129 | case LSM_SETID_RES: | |
1d045980 DH |
1130 | /* juggle the capabilities to follow [RES]UID changes unless |
1131 | * otherwise suppressed */ | |
d84f4f99 DH |
1132 | if (!issecure(SECURE_NO_SETUID_FIXUP)) |
1133 | cap_emulate_setxuid(new, old); | |
1da177e4 | 1134 | break; |
1da177e4 | 1135 | |
1d045980 | 1136 | case LSM_SETID_FS: |
4432b507 | 1137 | /* juggle the capabilities to follow FSUID changes, unless |
1d045980 DH |
1138 | * otherwise suppressed |
1139 | * | |
d84f4f99 DH |
1140 | * FIXME - is fsuser used for all CAP_FS_MASK capabilities? |
1141 | * if not, we might be a bit too harsh here. | |
1142 | */ | |
1143 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { | |
18815a18 EB |
1144 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
1145 | if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid)) | |
d84f4f99 DH |
1146 | new->cap_effective = |
1147 | cap_drop_fs_set(new->cap_effective); | |
1d045980 | 1148 | |
18815a18 | 1149 | if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid)) |
d84f4f99 DH |
1150 | new->cap_effective = |
1151 | cap_raise_fs_set(new->cap_effective, | |
1152 | new->cap_permitted); | |
1da177e4 | 1153 | } |
d84f4f99 | 1154 | break; |
1d045980 | 1155 | |
1da177e4 LT |
1156 | default: |
1157 | return -EINVAL; | |
1158 | } | |
1159 | ||
1160 | return 0; | |
1161 | } | |
1162 | ||
b5376771 SH |
1163 | /* |
1164 | * Rationale: code calling task_setscheduler, task_setioprio, and | |
1165 | * task_setnice, assumes that | |
1166 | * . if capable(cap_sys_nice), then those actions should be allowed | |
1167 | * . if not capable(cap_sys_nice), but acting on your own processes, | |
1168 | * then those actions should be allowed | |
1169 | * This is insufficient now since you can call code without suid, but | |
1170 | * yet with increased caps. | |
1171 | * So we check for increased caps on the target process. | |
1172 | */ | |
de45e806 | 1173 | static int cap_safe_nice(struct task_struct *p) |
b5376771 | 1174 | { |
f54fb863 | 1175 | int is_subset, ret = 0; |
c69e8d9c DH |
1176 | |
1177 | rcu_read_lock(); | |
1178 | is_subset = cap_issubset(__task_cred(p)->cap_permitted, | |
1179 | current_cred()->cap_permitted); | |
f54fb863 SH |
1180 | if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) |
1181 | ret = -EPERM; | |
c69e8d9c DH |
1182 | rcu_read_unlock(); |
1183 | ||
f54fb863 | 1184 | return ret; |
b5376771 SH |
1185 | } |
1186 | ||
1d045980 | 1187 | /** |
4432b507 | 1188 | * cap_task_setscheduler - Determine if scheduler policy change is permitted |
1d045980 | 1189 | * @p: The task to affect |
1d045980 | 1190 | * |
4432b507 | 1191 | * Determine if the requested scheduler policy change is permitted for the |
049ae601 RD |
1192 | * specified task. |
1193 | * | |
1194 | * Return: 0 if permission is granted, -ve if denied. | |
1d045980 | 1195 | */ |
b0ae1981 | 1196 | int cap_task_setscheduler(struct task_struct *p) |
b5376771 SH |
1197 | { |
1198 | return cap_safe_nice(p); | |
1199 | } | |
1200 | ||
1d045980 | 1201 | /** |
4432b507 | 1202 | * cap_task_setioprio - Determine if I/O priority change is permitted |
1d045980 DH |
1203 | * @p: The task to affect |
1204 | * @ioprio: The I/O priority to set | |
1205 | * | |
4432b507 | 1206 | * Determine if the requested I/O priority change is permitted for the specified |
049ae601 RD |
1207 | * task. |
1208 | * | |
1209 | * Return: 0 if permission is granted, -ve if denied. | |
1d045980 DH |
1210 | */ |
1211 | int cap_task_setioprio(struct task_struct *p, int ioprio) | |
b5376771 SH |
1212 | { |
1213 | return cap_safe_nice(p); | |
1214 | } | |
1215 | ||
1d045980 | 1216 | /** |
4432b507 | 1217 | * cap_task_setnice - Determine if task priority change is permitted |
1d045980 DH |
1218 | * @p: The task to affect |
1219 | * @nice: The nice value to set | |
1220 | * | |
4432b507 | 1221 | * Determine if the requested task priority change is permitted for the |
049ae601 RD |
1222 | * specified task. |
1223 | * | |
1224 | * Return: 0 if permission is granted, -ve if denied. | |
1d045980 DH |
1225 | */ |
1226 | int cap_task_setnice(struct task_struct *p, int nice) | |
b5376771 SH |
1227 | { |
1228 | return cap_safe_nice(p); | |
1229 | } | |
1230 | ||
3b7391de | 1231 | /* |
1d045980 DH |
1232 | * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from |
1233 | * the current task's bounding set. Returns 0 on success, -ve on error. | |
3b7391de | 1234 | */ |
6d6f3328 | 1235 | static int cap_prctl_drop(unsigned long cap) |
3b7391de | 1236 | { |
6d6f3328 TH |
1237 | struct cred *new; |
1238 | ||
160da84d | 1239 | if (!ns_capable(current_user_ns(), CAP_SETPCAP)) |
3b7391de SH |
1240 | return -EPERM; |
1241 | if (!cap_valid(cap)) | |
1242 | return -EINVAL; | |
d84f4f99 | 1243 | |
6d6f3328 TH |
1244 | new = prepare_creds(); |
1245 | if (!new) | |
1246 | return -ENOMEM; | |
d84f4f99 | 1247 | cap_lower(new->cap_bset, cap); |
6d6f3328 | 1248 | return commit_creds(new); |
3b7391de | 1249 | } |
3898b1b4 | 1250 | |
1d045980 DH |
1251 | /** |
1252 | * cap_task_prctl - Implement process control functions for this security module | |
1253 | * @option: The process control function requested | |
049ae601 RD |
1254 | * @arg2: The argument data for this function |
1255 | * @arg3: The argument data for this function | |
1256 | * @arg4: The argument data for this function | |
1257 | * @arg5: The argument data for this function | |
1d045980 DH |
1258 | * |
1259 | * Allow process control functions (sys_prctl()) to alter capabilities; may | |
1260 | * also deny access to other functions not otherwise implemented here. | |
1261 | * | |
049ae601 | 1262 | * Return: 0 or +ve on success, -ENOSYS if this function is not implemented |
1d045980 DH |
1263 | * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM |
1264 | * modules will consider performing the function. | |
1265 | */ | |
3898b1b4 | 1266 | int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, |
d84f4f99 | 1267 | unsigned long arg4, unsigned long arg5) |
3898b1b4 | 1268 | { |
6d6f3328 | 1269 | const struct cred *old = current_cred(); |
d84f4f99 | 1270 | struct cred *new; |
d84f4f99 | 1271 | |
3898b1b4 AM |
1272 | switch (option) { |
1273 | case PR_CAPBSET_READ: | |
1274 | if (!cap_valid(arg2)) | |
6d6f3328 TH |
1275 | return -EINVAL; |
1276 | return !!cap_raised(old->cap_bset, arg2); | |
d84f4f99 | 1277 | |
3898b1b4 | 1278 | case PR_CAPBSET_DROP: |
6d6f3328 | 1279 | return cap_prctl_drop(arg2); |
3898b1b4 AM |
1280 | |
1281 | /* | |
1282 | * The next four prctl's remain to assist with transitioning a | |
1283 | * system from legacy UID=0 based privilege (when filesystem | |
1284 | * capabilities are not in use) to a system using filesystem | |
1285 | * capabilities only - as the POSIX.1e draft intended. | |
1286 | * | |
1287 | * Note: | |
1288 | * | |
1289 | * PR_SET_SECUREBITS = | |
1290 | * issecure_mask(SECURE_KEEP_CAPS_LOCKED) | |
1291 | * | issecure_mask(SECURE_NOROOT) | |
1292 | * | issecure_mask(SECURE_NOROOT_LOCKED) | |
1293 | * | issecure_mask(SECURE_NO_SETUID_FIXUP) | |
1294 | * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) | |
1295 | * | |
1296 | * will ensure that the current process and all of its | |
1297 | * children will be locked into a pure | |
1298 | * capability-based-privilege environment. | |
1299 | */ | |
1300 | case PR_SET_SECUREBITS: | |
6d6f3328 TH |
1301 | if ((((old->securebits & SECURE_ALL_LOCKS) >> 1) |
1302 | & (old->securebits ^ arg2)) /*[1]*/ | |
1303 | || ((old->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/ | |
d84f4f99 | 1304 | || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ |
6a9de491 | 1305 | || (cap_capable(current_cred(), |
c1a85a00 MM |
1306 | current_cred()->user_ns, |
1307 | CAP_SETPCAP, | |
1308 | CAP_OPT_NONE) != 0) /*[4]*/ | |
3898b1b4 AM |
1309 | /* |
1310 | * [1] no changing of bits that are locked | |
1311 | * [2] no unlocking of locks | |
1312 | * [3] no setting of unsupported bits | |
1313 | * [4] doing anything requires privilege (go read about | |
1314 | * the "sendmail capabilities bug") | |
1315 | */ | |
d84f4f99 DH |
1316 | ) |
1317 | /* cannot change a locked bit */ | |
6d6f3328 TH |
1318 | return -EPERM; |
1319 | ||
1320 | new = prepare_creds(); | |
1321 | if (!new) | |
1322 | return -ENOMEM; | |
d84f4f99 | 1323 | new->securebits = arg2; |
6d6f3328 | 1324 | return commit_creds(new); |
d84f4f99 | 1325 | |
3898b1b4 | 1326 | case PR_GET_SECUREBITS: |
6d6f3328 | 1327 | return old->securebits; |
3898b1b4 | 1328 | |
3898b1b4 | 1329 | case PR_GET_KEEPCAPS: |
6d6f3328 | 1330 | return !!issecure(SECURE_KEEP_CAPS); |
d84f4f99 | 1331 | |
3898b1b4 AM |
1332 | case PR_SET_KEEPCAPS: |
1333 | if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ | |
6d6f3328 | 1334 | return -EINVAL; |
d84f4f99 | 1335 | if (issecure(SECURE_KEEP_CAPS_LOCKED)) |
6d6f3328 TH |
1336 | return -EPERM; |
1337 | ||
1338 | new = prepare_creds(); | |
1339 | if (!new) | |
1340 | return -ENOMEM; | |
d84f4f99 DH |
1341 | if (arg2) |
1342 | new->securebits |= issecure_mask(SECURE_KEEP_CAPS); | |
3898b1b4 | 1343 | else |
d84f4f99 | 1344 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
6d6f3328 | 1345 | return commit_creds(new); |
3898b1b4 | 1346 | |
58319057 AL |
1347 | case PR_CAP_AMBIENT: |
1348 | if (arg2 == PR_CAP_AMBIENT_CLEAR_ALL) { | |
1349 | if (arg3 | arg4 | arg5) | |
1350 | return -EINVAL; | |
1351 | ||
1352 | new = prepare_creds(); | |
1353 | if (!new) | |
1354 | return -ENOMEM; | |
1355 | cap_clear(new->cap_ambient); | |
1356 | return commit_creds(new); | |
1357 | } | |
1358 | ||
1359 | if (((!cap_valid(arg3)) | arg4 | arg5)) | |
1360 | return -EINVAL; | |
1361 | ||
1362 | if (arg2 == PR_CAP_AMBIENT_IS_SET) { | |
1363 | return !!cap_raised(current_cred()->cap_ambient, arg3); | |
1364 | } else if (arg2 != PR_CAP_AMBIENT_RAISE && | |
1365 | arg2 != PR_CAP_AMBIENT_LOWER) { | |
1366 | return -EINVAL; | |
1367 | } else { | |
1368 | if (arg2 == PR_CAP_AMBIENT_RAISE && | |
1369 | (!cap_raised(current_cred()->cap_permitted, arg3) || | |
1370 | !cap_raised(current_cred()->cap_inheritable, | |
746bf6d6 AL |
1371 | arg3) || |
1372 | issecure(SECURE_NO_CAP_AMBIENT_RAISE))) | |
58319057 AL |
1373 | return -EPERM; |
1374 | ||
1375 | new = prepare_creds(); | |
1376 | if (!new) | |
1377 | return -ENOMEM; | |
1378 | if (arg2 == PR_CAP_AMBIENT_RAISE) | |
1379 | cap_raise(new->cap_ambient, arg3); | |
1380 | else | |
1381 | cap_lower(new->cap_ambient, arg3); | |
1382 | return commit_creds(new); | |
1383 | } | |
1384 | ||
3898b1b4 AM |
1385 | default: |
1386 | /* No functionality available - continue with default */ | |
6d6f3328 | 1387 | return -ENOSYS; |
3898b1b4 | 1388 | } |
1da177e4 LT |
1389 | } |
1390 | ||
1d045980 DH |
1391 | /** |
1392 | * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted | |
1393 | * @mm: The VM space in which the new mapping is to be made | |
1394 | * @pages: The size of the mapping | |
1395 | * | |
1396 | * Determine whether the allocation of a new virtual mapping by the current | |
049ae601 RD |
1397 | * task is permitted. |
1398 | * | |
1399 | * Return: 1 if permission is granted, 0 if not. | |
1d045980 | 1400 | */ |
34b4e4aa | 1401 | int cap_vm_enough_memory(struct mm_struct *mm, long pages) |
1da177e4 LT |
1402 | { |
1403 | int cap_sys_admin = 0; | |
1404 | ||
c1a85a00 MM |
1405 | if (cap_capable(current_cred(), &init_user_ns, |
1406 | CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) == 0) | |
1da177e4 | 1407 | cap_sys_admin = 1; |
c1a85a00 | 1408 | |
b1d9e6b0 | 1409 | return cap_sys_admin; |
1da177e4 | 1410 | } |
7c73875e | 1411 | |
049ae601 | 1412 | /** |
d007794a | 1413 | * cap_mmap_addr - check if able to map given addr |
7c73875e | 1414 | * @addr: address attempting to be mapped |
7c73875e | 1415 | * |
6f262d8e | 1416 | * If the process is attempting to map memory below dac_mmap_min_addr they need |
7c73875e | 1417 | * CAP_SYS_RAWIO. The other parameters to this function are unused by the |
049ae601 RD |
1418 | * capability security module. |
1419 | * | |
1420 | * Return: 0 if this mapping should be allowed or -EPERM if not. | |
7c73875e | 1421 | */ |
d007794a | 1422 | int cap_mmap_addr(unsigned long addr) |
7c73875e EP |
1423 | { |
1424 | int ret = 0; | |
1425 | ||
a2551df7 | 1426 | if (addr < dac_mmap_min_addr) { |
6a9de491 | 1427 | ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO, |
c1a85a00 | 1428 | CAP_OPT_NONE); |
7c73875e EP |
1429 | /* set PF_SUPERPRIV if it turns out we allow the low mmap */ |
1430 | if (ret == 0) | |
1431 | current->flags |= PF_SUPERPRIV; | |
1432 | } | |
1433 | return ret; | |
1434 | } | |
d007794a | 1435 | |
e5467859 AV |
1436 | int cap_mmap_file(struct file *file, unsigned long reqprot, |
1437 | unsigned long prot, unsigned long flags) | |
d007794a | 1438 | { |
e5467859 | 1439 | return 0; |
d007794a | 1440 | } |
b1d9e6b0 CS |
1441 | |
1442 | #ifdef CONFIG_SECURITY | |
1443 | ||
b1a867ee | 1444 | static const struct lsm_id capability_lsmid = { |
f3b8788c CS |
1445 | .name = "capability", |
1446 | .id = LSM_ID_CAPABILITY, | |
1447 | }; | |
1448 | ||
f22f9aaf | 1449 | static struct security_hook_list capability_hooks[] __ro_after_init = { |
b1d9e6b0 CS |
1450 | LSM_HOOK_INIT(capable, cap_capable), |
1451 | LSM_HOOK_INIT(settime, cap_settime), | |
1452 | LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check), | |
1453 | LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme), | |
1454 | LSM_HOOK_INIT(capget, cap_capget), | |
1455 | LSM_HOOK_INIT(capset, cap_capset), | |
56305aa9 | 1456 | LSM_HOOK_INIT(bprm_creds_from_file, cap_bprm_creds_from_file), |
b1d9e6b0 CS |
1457 | LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv), |
1458 | LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv), | |
8db6c34f | 1459 | LSM_HOOK_INIT(inode_getsecurity, cap_inode_getsecurity), |
b1d9e6b0 CS |
1460 | LSM_HOOK_INIT(mmap_addr, cap_mmap_addr), |
1461 | LSM_HOOK_INIT(mmap_file, cap_mmap_file), | |
1462 | LSM_HOOK_INIT(task_fix_setuid, cap_task_fix_setuid), | |
1463 | LSM_HOOK_INIT(task_prctl, cap_task_prctl), | |
1464 | LSM_HOOK_INIT(task_setscheduler, cap_task_setscheduler), | |
1465 | LSM_HOOK_INIT(task_setioprio, cap_task_setioprio), | |
1466 | LSM_HOOK_INIT(task_setnice, cap_task_setnice), | |
1467 | LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory), | |
1468 | }; | |
1469 | ||
d117a154 | 1470 | static int __init capability_init(void) |
b1d9e6b0 | 1471 | { |
d69dece5 | 1472 | security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks), |
f3b8788c | 1473 | &capability_lsmid); |
d117a154 | 1474 | return 0; |
b1d9e6b0 CS |
1475 | } |
1476 | ||
d117a154 KC |
1477 | DEFINE_LSM(capability) = { |
1478 | .name = "capability", | |
1479 | .order = LSM_ORDER_FIRST, | |
1480 | .init = capability_init, | |
1481 | }; | |
1482 | ||
b1d9e6b0 | 1483 | #endif /* CONFIG_SECURITY */ |