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