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Commit | Line | Data |
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3e1c2515 | 1 | /* Common capabilities, needed by capability.o. |
1da177e4 LT |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2 of the License, or | |
6 | * (at your option) any later version. | |
7 | * | |
8 | */ | |
9 | ||
c59ede7b | 10 | #include <linux/capability.h> |
3fc689e9 | 11 | #include <linux/audit.h> |
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
b1d9e6b0 | 15 | #include <linux/lsm_hooks.h> |
1da177e4 LT |
16 | #include <linux/file.h> |
17 | #include <linux/mm.h> | |
18 | #include <linux/mman.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/swap.h> | |
1da177e4 LT |
21 | #include <linux/skbuff.h> |
22 | #include <linux/netlink.h> | |
23 | #include <linux/ptrace.h> | |
24 | #include <linux/xattr.h> | |
25 | #include <linux/hugetlb.h> | |
b5376771 | 26 | #include <linux/mount.h> |
b460cbc5 | 27 | #include <linux/sched.h> |
3898b1b4 AM |
28 | #include <linux/prctl.h> |
29 | #include <linux/securebits.h> | |
3486740a | 30 | #include <linux/user_namespace.h> |
40401530 | 31 | #include <linux/binfmts.h> |
51b79bee | 32 | #include <linux/personality.h> |
72c2d582 | 33 | |
b5f22a59 SH |
34 | /* |
35 | * If a non-root user executes a setuid-root binary in | |
36 | * !secure(SECURE_NOROOT) mode, then we raise capabilities. | |
37 | * However if fE is also set, then the intent is for only | |
38 | * the file capabilities to be applied, and the setuid-root | |
39 | * bit is left on either to change the uid (plausible) or | |
40 | * to get full privilege on a kernel without file capabilities | |
41 | * support. So in that case we do not raise capabilities. | |
42 | * | |
43 | * Warn if that happens, once per boot. | |
44 | */ | |
d7627467 | 45 | static void warn_setuid_and_fcaps_mixed(const char *fname) |
b5f22a59 SH |
46 | { |
47 | static int warned; | |
48 | if (!warned) { | |
49 | printk(KERN_INFO "warning: `%s' has both setuid-root and" | |
50 | " effective capabilities. Therefore not raising all" | |
51 | " capabilities.\n", fname); | |
52 | warned = 1; | |
53 | } | |
54 | } | |
55 | ||
1d045980 DH |
56 | /** |
57 | * cap_capable - Determine whether a task has a particular effective capability | |
3699c53c | 58 | * @cred: The credentials to use |
3486740a | 59 | * @ns: The user namespace in which we need the capability |
1d045980 DH |
60 | * @cap: The capability to check for |
61 | * @audit: Whether to write an audit message or not | |
62 | * | |
63 | * Determine whether the nominated task has the specified capability amongst | |
64 | * its effective set, returning 0 if it does, -ve if it does not. | |
65 | * | |
3699c53c DH |
66 | * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable() |
67 | * and has_capability() functions. That is, it has the reverse semantics: | |
68 | * cap_has_capability() returns 0 when a task has a capability, but the | |
69 | * kernel's capable() and has_capability() returns 1 for this case. | |
a6dbb1ef | 70 | */ |
6a9de491 EP |
71 | int cap_capable(const struct cred *cred, struct user_namespace *targ_ns, |
72 | int cap, int audit) | |
1da177e4 | 73 | { |
520d9eab | 74 | struct user_namespace *ns = targ_ns; |
3486740a | 75 | |
520d9eab EB |
76 | /* See if cred has the capability in the target user namespace |
77 | * by examining the target user namespace and all of the target | |
78 | * user namespace's parents. | |
79 | */ | |
80 | for (;;) { | |
3486740a | 81 | /* Do we have the necessary capabilities? */ |
520d9eab | 82 | if (ns == cred->user_ns) |
3486740a SH |
83 | return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM; |
84 | ||
64db4c7f KT |
85 | /* |
86 | * If we're already at a lower level than we're looking for, | |
87 | * we're done searching. | |
88 | */ | |
89 | if (ns->level <= cred->user_ns->level) | |
3486740a SH |
90 | return -EPERM; |
91 | ||
520d9eab EB |
92 | /* |
93 | * The owner of the user namespace in the parent of the | |
94 | * user namespace has all caps. | |
95 | */ | |
96 | if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid)) | |
97 | return 0; | |
98 | ||
3486740a | 99 | /* |
520d9eab | 100 | * If you have a capability in a parent user ns, then you have |
3486740a SH |
101 | * it over all children user namespaces as well. |
102 | */ | |
520d9eab | 103 | ns = ns->parent; |
3486740a SH |
104 | } |
105 | ||
106 | /* We never get here */ | |
1da177e4 LT |
107 | } |
108 | ||
1d045980 DH |
109 | /** |
110 | * cap_settime - Determine whether the current process may set the system clock | |
111 | * @ts: The time to set | |
112 | * @tz: The timezone to set | |
113 | * | |
114 | * Determine whether the current process may set the system clock and timezone | |
115 | * information, returning 0 if permission granted, -ve if denied. | |
116 | */ | |
457db29b | 117 | int cap_settime(const struct timespec64 *ts, const struct timezone *tz) |
1da177e4 LT |
118 | { |
119 | if (!capable(CAP_SYS_TIME)) | |
120 | return -EPERM; | |
121 | return 0; | |
122 | } | |
123 | ||
1d045980 | 124 | /** |
9e48858f | 125 | * cap_ptrace_access_check - Determine whether the current process may access |
1d045980 DH |
126 | * another |
127 | * @child: The process to be accessed | |
128 | * @mode: The mode of attachment. | |
129 | * | |
8409cca7 SH |
130 | * If we are in the same or an ancestor user_ns and have all the target |
131 | * task's capabilities, then ptrace access is allowed. | |
132 | * If we have the ptrace capability to the target user_ns, then ptrace | |
133 | * access is allowed. | |
134 | * Else denied. | |
135 | * | |
1d045980 DH |
136 | * Determine whether a process may access another, returning 0 if permission |
137 | * granted, -ve if denied. | |
138 | */ | |
9e48858f | 139 | int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) |
1da177e4 | 140 | { |
c69e8d9c | 141 | int ret = 0; |
8409cca7 | 142 | const struct cred *cred, *child_cred; |
caaee623 | 143 | const kernel_cap_t *caller_caps; |
c69e8d9c DH |
144 | |
145 | rcu_read_lock(); | |
8409cca7 SH |
146 | cred = current_cred(); |
147 | child_cred = __task_cred(child); | |
caaee623 JH |
148 | if (mode & PTRACE_MODE_FSCREDS) |
149 | caller_caps = &cred->cap_effective; | |
150 | else | |
151 | caller_caps = &cred->cap_permitted; | |
c4a4d603 | 152 | if (cred->user_ns == child_cred->user_ns && |
caaee623 | 153 | cap_issubset(child_cred->cap_permitted, *caller_caps)) |
8409cca7 | 154 | goto out; |
c4a4d603 | 155 | if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
156 | goto out; |
157 | ret = -EPERM; | |
158 | out: | |
c69e8d9c DH |
159 | rcu_read_unlock(); |
160 | return ret; | |
5cd9c58f DH |
161 | } |
162 | ||
1d045980 DH |
163 | /** |
164 | * cap_ptrace_traceme - Determine whether another process may trace the current | |
165 | * @parent: The task proposed to be the tracer | |
166 | * | |
8409cca7 SH |
167 | * If parent is in the same or an ancestor user_ns and has all current's |
168 | * capabilities, then ptrace access is allowed. | |
169 | * If parent has the ptrace capability to current's user_ns, then ptrace | |
170 | * access is allowed. | |
171 | * Else denied. | |
172 | * | |
1d045980 DH |
173 | * Determine whether the nominated task is permitted to trace the current |
174 | * process, returning 0 if permission is granted, -ve if denied. | |
175 | */ | |
5cd9c58f DH |
176 | int cap_ptrace_traceme(struct task_struct *parent) |
177 | { | |
c69e8d9c | 178 | int ret = 0; |
8409cca7 | 179 | const struct cred *cred, *child_cred; |
c69e8d9c DH |
180 | |
181 | rcu_read_lock(); | |
8409cca7 SH |
182 | cred = __task_cred(parent); |
183 | child_cred = current_cred(); | |
c4a4d603 | 184 | if (cred->user_ns == child_cred->user_ns && |
8409cca7 SH |
185 | cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) |
186 | goto out; | |
c4a4d603 | 187 | if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
188 | goto out; |
189 | ret = -EPERM; | |
190 | out: | |
c69e8d9c DH |
191 | rcu_read_unlock(); |
192 | return ret; | |
1da177e4 LT |
193 | } |
194 | ||
1d045980 DH |
195 | /** |
196 | * cap_capget - Retrieve a task's capability sets | |
197 | * @target: The task from which to retrieve the capability sets | |
198 | * @effective: The place to record the effective set | |
199 | * @inheritable: The place to record the inheritable set | |
200 | * @permitted: The place to record the permitted set | |
201 | * | |
202 | * This function retrieves the capabilities of the nominated task and returns | |
203 | * them to the caller. | |
204 | */ | |
205 | int cap_capget(struct task_struct *target, kernel_cap_t *effective, | |
206 | kernel_cap_t *inheritable, kernel_cap_t *permitted) | |
1da177e4 | 207 | { |
c69e8d9c | 208 | const struct cred *cred; |
b6dff3ec | 209 | |
1da177e4 | 210 | /* Derived from kernel/capability.c:sys_capget. */ |
c69e8d9c DH |
211 | rcu_read_lock(); |
212 | cred = __task_cred(target); | |
b6dff3ec DH |
213 | *effective = cred->cap_effective; |
214 | *inheritable = cred->cap_inheritable; | |
215 | *permitted = cred->cap_permitted; | |
c69e8d9c | 216 | rcu_read_unlock(); |
1da177e4 LT |
217 | return 0; |
218 | } | |
219 | ||
1d045980 DH |
220 | /* |
221 | * Determine whether the inheritable capabilities are limited to the old | |
222 | * permitted set. Returns 1 if they are limited, 0 if they are not. | |
223 | */ | |
72c2d582 AM |
224 | static inline int cap_inh_is_capped(void) |
225 | { | |
72c2d582 | 226 | |
1d045980 DH |
227 | /* they are so limited unless the current task has the CAP_SETPCAP |
228 | * capability | |
229 | */ | |
c4a4d603 | 230 | if (cap_capable(current_cred(), current_cred()->user_ns, |
6a9de491 | 231 | CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0) |
1d045980 | 232 | return 0; |
1d045980 | 233 | return 1; |
1209726c | 234 | } |
72c2d582 | 235 | |
1d045980 DH |
236 | /** |
237 | * cap_capset - Validate and apply proposed changes to current's capabilities | |
238 | * @new: The proposed new credentials; alterations should be made here | |
239 | * @old: The current task's current credentials | |
240 | * @effective: A pointer to the proposed new effective capabilities set | |
241 | * @inheritable: A pointer to the proposed new inheritable capabilities set | |
242 | * @permitted: A pointer to the proposed new permitted capabilities set | |
243 | * | |
244 | * This function validates and applies a proposed mass change to the current | |
245 | * process's capability sets. The changes are made to the proposed new | |
246 | * credentials, and assuming no error, will be committed by the caller of LSM. | |
247 | */ | |
d84f4f99 DH |
248 | int cap_capset(struct cred *new, |
249 | const struct cred *old, | |
250 | const kernel_cap_t *effective, | |
251 | const kernel_cap_t *inheritable, | |
252 | const kernel_cap_t *permitted) | |
1da177e4 | 253 | { |
d84f4f99 DH |
254 | if (cap_inh_is_capped() && |
255 | !cap_issubset(*inheritable, | |
256 | cap_combine(old->cap_inheritable, | |
257 | old->cap_permitted))) | |
72c2d582 | 258 | /* incapable of using this inheritable set */ |
1da177e4 | 259 | return -EPERM; |
d84f4f99 | 260 | |
3b7391de | 261 | if (!cap_issubset(*inheritable, |
d84f4f99 DH |
262 | cap_combine(old->cap_inheritable, |
263 | old->cap_bset))) | |
3b7391de SH |
264 | /* no new pI capabilities outside bounding set */ |
265 | return -EPERM; | |
1da177e4 LT |
266 | |
267 | /* verify restrictions on target's new Permitted set */ | |
d84f4f99 | 268 | if (!cap_issubset(*permitted, old->cap_permitted)) |
1da177e4 | 269 | return -EPERM; |
1da177e4 LT |
270 | |
271 | /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ | |
d84f4f99 | 272 | if (!cap_issubset(*effective, *permitted)) |
1da177e4 | 273 | return -EPERM; |
1da177e4 | 274 | |
d84f4f99 DH |
275 | new->cap_effective = *effective; |
276 | new->cap_inheritable = *inheritable; | |
277 | new->cap_permitted = *permitted; | |
58319057 AL |
278 | |
279 | /* | |
280 | * Mask off ambient bits that are no longer both permitted and | |
281 | * inheritable. | |
282 | */ | |
283 | new->cap_ambient = cap_intersect(new->cap_ambient, | |
284 | cap_intersect(*permitted, | |
285 | *inheritable)); | |
286 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
287 | return -EINVAL; | |
1da177e4 LT |
288 | return 0; |
289 | } | |
290 | ||
1d045980 DH |
291 | /* |
292 | * Clear proposed capability sets for execve(). | |
293 | */ | |
b5376771 SH |
294 | static inline void bprm_clear_caps(struct linux_binprm *bprm) |
295 | { | |
a6f76f23 | 296 | cap_clear(bprm->cred->cap_permitted); |
b5376771 SH |
297 | bprm->cap_effective = false; |
298 | } | |
299 | ||
1d045980 DH |
300 | /** |
301 | * cap_inode_need_killpriv - Determine if inode change affects privileges | |
302 | * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV | |
303 | * | |
304 | * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV | |
305 | * affects the security markings on that inode, and if it is, should | |
306 | * inode_killpriv() be invoked or the change rejected? | |
307 | * | |
308 | * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and | |
309 | * -ve to deny the change. | |
310 | */ | |
b5376771 SH |
311 | int cap_inode_need_killpriv(struct dentry *dentry) |
312 | { | |
c6f493d6 | 313 | struct inode *inode = d_backing_inode(dentry); |
b5376771 SH |
314 | int error; |
315 | ||
5d6c3191 AG |
316 | error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0); |
317 | return error > 0; | |
b5376771 SH |
318 | } |
319 | ||
1d045980 DH |
320 | /** |
321 | * cap_inode_killpriv - Erase the security markings on an inode | |
322 | * @dentry: The inode/dentry to alter | |
323 | * | |
324 | * Erase the privilege-enhancing security markings on an inode. | |
325 | * | |
326 | * Returns 0 if successful, -ve on error. | |
327 | */ | |
b5376771 SH |
328 | int cap_inode_killpriv(struct dentry *dentry) |
329 | { | |
5d6c3191 | 330 | int error; |
b5376771 | 331 | |
5d6c3191 AG |
332 | error = __vfs_removexattr(dentry, XATTR_NAME_CAPS); |
333 | if (error == -EOPNOTSUPP) | |
334 | error = 0; | |
335 | return error; | |
b5376771 SH |
336 | } |
337 | ||
1d045980 DH |
338 | /* |
339 | * Calculate the new process capability sets from the capability sets attached | |
340 | * to a file. | |
341 | */ | |
c0b00441 | 342 | static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, |
a6f76f23 | 343 | struct linux_binprm *bprm, |
4d49f671 ZL |
344 | bool *effective, |
345 | bool *has_cap) | |
b5376771 | 346 | { |
a6f76f23 | 347 | struct cred *new = bprm->cred; |
c0b00441 EP |
348 | unsigned i; |
349 | int ret = 0; | |
350 | ||
351 | if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) | |
a6f76f23 | 352 | *effective = true; |
c0b00441 | 353 | |
4d49f671 ZL |
354 | if (caps->magic_etc & VFS_CAP_REVISION_MASK) |
355 | *has_cap = true; | |
356 | ||
c0b00441 EP |
357 | CAP_FOR_EACH_U32(i) { |
358 | __u32 permitted = caps->permitted.cap[i]; | |
359 | __u32 inheritable = caps->inheritable.cap[i]; | |
360 | ||
361 | /* | |
362 | * pP' = (X & fP) | (pI & fI) | |
58319057 | 363 | * The addition of pA' is handled later. |
c0b00441 | 364 | */ |
a6f76f23 DH |
365 | new->cap_permitted.cap[i] = |
366 | (new->cap_bset.cap[i] & permitted) | | |
367 | (new->cap_inheritable.cap[i] & inheritable); | |
c0b00441 | 368 | |
a6f76f23 DH |
369 | if (permitted & ~new->cap_permitted.cap[i]) |
370 | /* insufficient to execute correctly */ | |
c0b00441 | 371 | ret = -EPERM; |
c0b00441 EP |
372 | } |
373 | ||
374 | /* | |
375 | * For legacy apps, with no internal support for recognizing they | |
376 | * do not have enough capabilities, we return an error if they are | |
377 | * missing some "forced" (aka file-permitted) capabilities. | |
378 | */ | |
a6f76f23 | 379 | return *effective ? ret : 0; |
c0b00441 EP |
380 | } |
381 | ||
1d045980 DH |
382 | /* |
383 | * Extract the on-exec-apply capability sets for an executable file. | |
384 | */ | |
c0b00441 EP |
385 | int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) |
386 | { | |
c6f493d6 | 387 | struct inode *inode = d_backing_inode(dentry); |
b5376771 | 388 | __u32 magic_etc; |
e338d263 | 389 | unsigned tocopy, i; |
c0b00441 EP |
390 | int size; |
391 | struct vfs_cap_data caps; | |
392 | ||
393 | memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); | |
394 | ||
5d6c3191 | 395 | if (!inode) |
c0b00441 EP |
396 | return -ENODATA; |
397 | ||
5d6c3191 AG |
398 | size = __vfs_getxattr((struct dentry *)dentry, inode, |
399 | XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ); | |
a6f76f23 | 400 | if (size == -ENODATA || size == -EOPNOTSUPP) |
c0b00441 EP |
401 | /* no data, that's ok */ |
402 | return -ENODATA; | |
c0b00441 EP |
403 | if (size < 0) |
404 | return size; | |
b5376771 | 405 | |
e338d263 | 406 | if (size < sizeof(magic_etc)) |
b5376771 SH |
407 | return -EINVAL; |
408 | ||
c0b00441 | 409 | cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc); |
b5376771 | 410 | |
a6f76f23 | 411 | switch (magic_etc & VFS_CAP_REVISION_MASK) { |
e338d263 AM |
412 | case VFS_CAP_REVISION_1: |
413 | if (size != XATTR_CAPS_SZ_1) | |
414 | return -EINVAL; | |
415 | tocopy = VFS_CAP_U32_1; | |
416 | break; | |
417 | case VFS_CAP_REVISION_2: | |
418 | if (size != XATTR_CAPS_SZ_2) | |
419 | return -EINVAL; | |
420 | tocopy = VFS_CAP_U32_2; | |
421 | break; | |
b5376771 SH |
422 | default: |
423 | return -EINVAL; | |
424 | } | |
e338d263 | 425 | |
5459c164 | 426 | CAP_FOR_EACH_U32(i) { |
c0b00441 EP |
427 | if (i >= tocopy) |
428 | break; | |
429 | cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted); | |
430 | cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable); | |
e338d263 | 431 | } |
a6f76f23 | 432 | |
7d8b6c63 EP |
433 | cpu_caps->permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; |
434 | cpu_caps->inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; | |
435 | ||
c0b00441 | 436 | return 0; |
b5376771 SH |
437 | } |
438 | ||
1d045980 DH |
439 | /* |
440 | * Attempt to get the on-exec apply capability sets for an executable file from | |
441 | * its xattrs and, if present, apply them to the proposed credentials being | |
442 | * constructed by execve(). | |
443 | */ | |
4d49f671 | 444 | static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_cap) |
b5376771 | 445 | { |
b5376771 | 446 | int rc = 0; |
c0b00441 | 447 | struct cpu_vfs_cap_data vcaps; |
b5376771 | 448 | |
3318a386 SH |
449 | bprm_clear_caps(bprm); |
450 | ||
1f29fae2 SH |
451 | if (!file_caps_enabled) |
452 | return 0; | |
453 | ||
380cf5ba | 454 | if (!mnt_may_suid(bprm->file->f_path.mnt)) |
b5376771 | 455 | return 0; |
380cf5ba AL |
456 | |
457 | /* | |
458 | * This check is redundant with mnt_may_suid() but is kept to make | |
459 | * explicit that capability bits are limited to s_user_ns and its | |
460 | * descendants. | |
461 | */ | |
d07b846f SF |
462 | if (!current_in_userns(bprm->file->f_path.mnt->mnt_sb->s_user_ns)) |
463 | return 0; | |
b5376771 | 464 | |
f4a4a8b1 | 465 | rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps); |
c0b00441 EP |
466 | if (rc < 0) { |
467 | if (rc == -EINVAL) | |
468 | printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n", | |
469 | __func__, rc, bprm->filename); | |
470 | else if (rc == -ENODATA) | |
471 | rc = 0; | |
b5376771 SH |
472 | goto out; |
473 | } | |
b5376771 | 474 | |
4d49f671 | 475 | rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_cap); |
a6f76f23 DH |
476 | if (rc == -EINVAL) |
477 | printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n", | |
478 | __func__, rc, bprm->filename); | |
b5376771 SH |
479 | |
480 | out: | |
b5376771 SH |
481 | if (rc) |
482 | bprm_clear_caps(bprm); | |
483 | ||
484 | return rc; | |
485 | } | |
486 | ||
1d045980 DH |
487 | /** |
488 | * cap_bprm_set_creds - Set up the proposed credentials for execve(). | |
489 | * @bprm: The execution parameters, including the proposed creds | |
490 | * | |
491 | * Set up the proposed credentials for a new execution context being | |
492 | * constructed by execve(). The proposed creds in @bprm->cred is altered, | |
493 | * which won't take effect immediately. Returns 0 if successful, -ve on error. | |
a6f76f23 DH |
494 | */ |
495 | int cap_bprm_set_creds(struct linux_binprm *bprm) | |
1da177e4 | 496 | { |
a6f76f23 DH |
497 | const struct cred *old = current_cred(); |
498 | struct cred *new = bprm->cred; | |
58319057 | 499 | bool effective, has_cap = false, is_setid; |
b5376771 | 500 | int ret; |
18815a18 | 501 | kuid_t root_uid; |
1da177e4 | 502 | |
58319057 AL |
503 | if (WARN_ON(!cap_ambient_invariant_ok(old))) |
504 | return -EPERM; | |
505 | ||
a6f76f23 | 506 | effective = false; |
4d49f671 | 507 | ret = get_file_caps(bprm, &effective, &has_cap); |
a6f76f23 DH |
508 | if (ret < 0) |
509 | return ret; | |
1da177e4 | 510 | |
18815a18 EB |
511 | root_uid = make_kuid(new->user_ns, 0); |
512 | ||
5459c164 | 513 | if (!issecure(SECURE_NOROOT)) { |
b5f22a59 SH |
514 | /* |
515 | * If the legacy file capability is set, then don't set privs | |
516 | * for a setuid root binary run by a non-root user. Do set it | |
517 | * for a root user just to cause least surprise to an admin. | |
518 | */ | |
18815a18 | 519 | if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { |
b5f22a59 SH |
520 | warn_setuid_and_fcaps_mixed(bprm->filename); |
521 | goto skip; | |
522 | } | |
5459c164 AM |
523 | /* |
524 | * To support inheritance of root-permissions and suid-root | |
525 | * executables under compatibility mode, we override the | |
526 | * capability sets for the file. | |
527 | * | |
a6f76f23 | 528 | * If only the real uid is 0, we do not set the effective bit. |
5459c164 | 529 | */ |
18815a18 | 530 | if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { |
5459c164 | 531 | /* pP' = (cap_bset & ~0) | (pI & ~0) */ |
a6f76f23 DH |
532 | new->cap_permitted = cap_combine(old->cap_bset, |
533 | old->cap_inheritable); | |
1da177e4 | 534 | } |
18815a18 | 535 | if (uid_eq(new->euid, root_uid)) |
a6f76f23 | 536 | effective = true; |
1da177e4 | 537 | } |
b5f22a59 | 538 | skip: |
b5376771 | 539 | |
d52fc5dd EP |
540 | /* if we have fs caps, clear dangerous personality flags */ |
541 | if (!cap_issubset(new->cap_permitted, old->cap_permitted)) | |
542 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
543 | ||
544 | ||
a6f76f23 | 545 | /* Don't let someone trace a set[ug]id/setpcap binary with the revised |
259e5e6c AL |
546 | * credentials unless they have the appropriate permit. |
547 | * | |
548 | * In addition, if NO_NEW_PRIVS, then ensure we get no new privs. | |
a6f76f23 | 549 | */ |
58319057 AL |
550 | is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid); |
551 | ||
552 | if ((is_setid || | |
a6f76f23 | 553 | !cap_issubset(new->cap_permitted, old->cap_permitted)) && |
9227dd2a | 554 | ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) || |
20523132 | 555 | !ptracer_capable(current, new->user_ns))) { |
a6f76f23 | 556 | /* downgrade; they get no more than they had, and maybe less */ |
70169420 | 557 | if (!ns_capable(new->user_ns, CAP_SETUID) || |
259e5e6c | 558 | (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) { |
a6f76f23 DH |
559 | new->euid = new->uid; |
560 | new->egid = new->gid; | |
1da177e4 | 561 | } |
b3a222e5 SH |
562 | new->cap_permitted = cap_intersect(new->cap_permitted, |
563 | old->cap_permitted); | |
1da177e4 LT |
564 | } |
565 | ||
a6f76f23 DH |
566 | new->suid = new->fsuid = new->euid; |
567 | new->sgid = new->fsgid = new->egid; | |
1da177e4 | 568 | |
58319057 AL |
569 | /* File caps or setid cancels ambient. */ |
570 | if (has_cap || is_setid) | |
571 | cap_clear(new->cap_ambient); | |
572 | ||
573 | /* | |
574 | * Now that we've computed pA', update pP' to give: | |
575 | * pP' = (X & fP) | (pI & fI) | pA' | |
576 | */ | |
577 | new->cap_permitted = cap_combine(new->cap_permitted, new->cap_ambient); | |
578 | ||
579 | /* | |
580 | * Set pE' = (fE ? pP' : pA'). Because pA' is zero if fE is set, | |
581 | * this is the same as pE' = (fE ? pP' : 0) | pA'. | |
582 | */ | |
4bf2ea77 EP |
583 | if (effective) |
584 | new->cap_effective = new->cap_permitted; | |
585 | else | |
58319057 AL |
586 | new->cap_effective = new->cap_ambient; |
587 | ||
588 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
589 | return -EPERM; | |
590 | ||
a6f76f23 | 591 | bprm->cap_effective = effective; |
1da177e4 | 592 | |
3fc689e9 EP |
593 | /* |
594 | * Audit candidate if current->cap_effective is set | |
595 | * | |
596 | * We do not bother to audit if 3 things are true: | |
597 | * 1) cap_effective has all caps | |
598 | * 2) we are root | |
599 | * 3) root is supposed to have all caps (SECURE_NOROOT) | |
600 | * Since this is just a normal root execing a process. | |
601 | * | |
602 | * Number 1 above might fail if you don't have a full bset, but I think | |
603 | * that is interesting information to audit. | |
604 | */ | |
58319057 | 605 | if (!cap_issubset(new->cap_effective, new->cap_ambient)) { |
d84f4f99 | 606 | if (!cap_issubset(CAP_FULL_SET, new->cap_effective) || |
18815a18 | 607 | !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) || |
a6f76f23 DH |
608 | issecure(SECURE_NOROOT)) { |
609 | ret = audit_log_bprm_fcaps(bprm, new, old); | |
610 | if (ret < 0) | |
611 | return ret; | |
612 | } | |
3fc689e9 | 613 | } |
1da177e4 | 614 | |
d84f4f99 | 615 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
58319057 AL |
616 | |
617 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
618 | return -EPERM; | |
619 | ||
a6f76f23 | 620 | return 0; |
1da177e4 LT |
621 | } |
622 | ||
1d045980 DH |
623 | /** |
624 | * cap_bprm_secureexec - Determine whether a secure execution is required | |
625 | * @bprm: The execution parameters | |
626 | * | |
627 | * Determine whether a secure execution is required, return 1 if it is, and 0 | |
628 | * if it is not. | |
629 | * | |
630 | * The credentials have been committed by this point, and so are no longer | |
631 | * available through @bprm->cred. | |
a6f76f23 DH |
632 | */ |
633 | int cap_bprm_secureexec(struct linux_binprm *bprm) | |
1da177e4 | 634 | { |
c69e8d9c | 635 | const struct cred *cred = current_cred(); |
18815a18 | 636 | kuid_t root_uid = make_kuid(cred->user_ns, 0); |
b6dff3ec | 637 | |
18815a18 | 638 | if (!uid_eq(cred->uid, root_uid)) { |
b5376771 SH |
639 | if (bprm->cap_effective) |
640 | return 1; | |
58319057 | 641 | if (!cap_issubset(cred->cap_permitted, cred->cap_ambient)) |
b5376771 SH |
642 | return 1; |
643 | } | |
644 | ||
18815a18 EB |
645 | return (!uid_eq(cred->euid, cred->uid) || |
646 | !gid_eq(cred->egid, cred->gid)); | |
1da177e4 LT |
647 | } |
648 | ||
1d045980 DH |
649 | /** |
650 | * cap_inode_setxattr - Determine whether an xattr may be altered | |
651 | * @dentry: The inode/dentry being altered | |
652 | * @name: The name of the xattr to be changed | |
653 | * @value: The value that the xattr will be changed to | |
654 | * @size: The size of value | |
655 | * @flags: The replacement flag | |
656 | * | |
657 | * Determine whether an xattr may be altered or set on an inode, returning 0 if | |
658 | * permission is granted, -ve if denied. | |
659 | * | |
660 | * This is used to make sure security xattrs don't get updated or set by those | |
661 | * who aren't privileged to do so. | |
662 | */ | |
8f0cfa52 DH |
663 | int cap_inode_setxattr(struct dentry *dentry, const char *name, |
664 | const void *value, size_t size, int flags) | |
1da177e4 | 665 | { |
b5376771 SH |
666 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
667 | if (!capable(CAP_SETFCAP)) | |
668 | return -EPERM; | |
669 | return 0; | |
1d045980 DH |
670 | } |
671 | ||
672 | if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
c5b60b5e | 673 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
1da177e4 LT |
674 | !capable(CAP_SYS_ADMIN)) |
675 | return -EPERM; | |
676 | return 0; | |
677 | } | |
678 | ||
1d045980 DH |
679 | /** |
680 | * cap_inode_removexattr - Determine whether an xattr may be removed | |
681 | * @dentry: The inode/dentry being altered | |
682 | * @name: The name of the xattr to be changed | |
683 | * | |
684 | * Determine whether an xattr may be removed from an inode, returning 0 if | |
685 | * permission is granted, -ve if denied. | |
686 | * | |
687 | * This is used to make sure security xattrs don't get removed by those who | |
688 | * aren't privileged to remove them. | |
689 | */ | |
8f0cfa52 | 690 | int cap_inode_removexattr(struct dentry *dentry, const char *name) |
1da177e4 | 691 | { |
b5376771 SH |
692 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
693 | if (!capable(CAP_SETFCAP)) | |
694 | return -EPERM; | |
695 | return 0; | |
1d045980 DH |
696 | } |
697 | ||
698 | if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
c5b60b5e | 699 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
1da177e4 LT |
700 | !capable(CAP_SYS_ADMIN)) |
701 | return -EPERM; | |
702 | return 0; | |
703 | } | |
704 | ||
a6f76f23 | 705 | /* |
1da177e4 LT |
706 | * cap_emulate_setxuid() fixes the effective / permitted capabilities of |
707 | * a process after a call to setuid, setreuid, or setresuid. | |
708 | * | |
709 | * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of | |
710 | * {r,e,s}uid != 0, the permitted and effective capabilities are | |
711 | * cleared. | |
712 | * | |
713 | * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective | |
714 | * capabilities of the process are cleared. | |
715 | * | |
716 | * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective | |
717 | * capabilities are set to the permitted capabilities. | |
718 | * | |
a6f76f23 | 719 | * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should |
1da177e4 LT |
720 | * never happen. |
721 | * | |
a6f76f23 | 722 | * -astor |
1da177e4 LT |
723 | * |
724 | * cevans - New behaviour, Oct '99 | |
725 | * A process may, via prctl(), elect to keep its capabilities when it | |
726 | * calls setuid() and switches away from uid==0. Both permitted and | |
727 | * effective sets will be retained. | |
728 | * Without this change, it was impossible for a daemon to drop only some | |
729 | * of its privilege. The call to setuid(!=0) would drop all privileges! | |
730 | * Keeping uid 0 is not an option because uid 0 owns too many vital | |
731 | * files.. | |
732 | * Thanks to Olaf Kirch and Peter Benie for spotting this. | |
733 | */ | |
d84f4f99 | 734 | static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old) |
1da177e4 | 735 | { |
18815a18 EB |
736 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
737 | ||
738 | if ((uid_eq(old->uid, root_uid) || | |
739 | uid_eq(old->euid, root_uid) || | |
740 | uid_eq(old->suid, root_uid)) && | |
741 | (!uid_eq(new->uid, root_uid) && | |
742 | !uid_eq(new->euid, root_uid) && | |
58319057 AL |
743 | !uid_eq(new->suid, root_uid))) { |
744 | if (!issecure(SECURE_KEEP_CAPS)) { | |
745 | cap_clear(new->cap_permitted); | |
746 | cap_clear(new->cap_effective); | |
747 | } | |
748 | ||
749 | /* | |
750 | * Pre-ambient programs expect setresuid to nonroot followed | |
751 | * by exec to drop capabilities. We should make sure that | |
752 | * this remains the case. | |
753 | */ | |
754 | cap_clear(new->cap_ambient); | |
1da177e4 | 755 | } |
18815a18 | 756 | if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid)) |
d84f4f99 | 757 | cap_clear(new->cap_effective); |
18815a18 | 758 | if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid)) |
d84f4f99 | 759 | new->cap_effective = new->cap_permitted; |
1da177e4 LT |
760 | } |
761 | ||
1d045980 DH |
762 | /** |
763 | * cap_task_fix_setuid - Fix up the results of setuid() call | |
764 | * @new: The proposed credentials | |
765 | * @old: The current task's current credentials | |
766 | * @flags: Indications of what has changed | |
767 | * | |
768 | * Fix up the results of setuid() call before the credential changes are | |
769 | * actually applied, returning 0 to grant the changes, -ve to deny them. | |
770 | */ | |
d84f4f99 | 771 | int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) |
1da177e4 LT |
772 | { |
773 | switch (flags) { | |
774 | case LSM_SETID_RE: | |
775 | case LSM_SETID_ID: | |
776 | case LSM_SETID_RES: | |
1d045980 DH |
777 | /* juggle the capabilities to follow [RES]UID changes unless |
778 | * otherwise suppressed */ | |
d84f4f99 DH |
779 | if (!issecure(SECURE_NO_SETUID_FIXUP)) |
780 | cap_emulate_setxuid(new, old); | |
1da177e4 | 781 | break; |
1da177e4 | 782 | |
1d045980 DH |
783 | case LSM_SETID_FS: |
784 | /* juggle the capabilties to follow FSUID changes, unless | |
785 | * otherwise suppressed | |
786 | * | |
d84f4f99 DH |
787 | * FIXME - is fsuser used for all CAP_FS_MASK capabilities? |
788 | * if not, we might be a bit too harsh here. | |
789 | */ | |
790 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { | |
18815a18 EB |
791 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
792 | if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid)) | |
d84f4f99 DH |
793 | new->cap_effective = |
794 | cap_drop_fs_set(new->cap_effective); | |
1d045980 | 795 | |
18815a18 | 796 | if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid)) |
d84f4f99 DH |
797 | new->cap_effective = |
798 | cap_raise_fs_set(new->cap_effective, | |
799 | new->cap_permitted); | |
1da177e4 | 800 | } |
d84f4f99 | 801 | break; |
1d045980 | 802 | |
1da177e4 LT |
803 | default: |
804 | return -EINVAL; | |
805 | } | |
806 | ||
807 | return 0; | |
808 | } | |
809 | ||
b5376771 SH |
810 | /* |
811 | * Rationale: code calling task_setscheduler, task_setioprio, and | |
812 | * task_setnice, assumes that | |
813 | * . if capable(cap_sys_nice), then those actions should be allowed | |
814 | * . if not capable(cap_sys_nice), but acting on your own processes, | |
815 | * then those actions should be allowed | |
816 | * This is insufficient now since you can call code without suid, but | |
817 | * yet with increased caps. | |
818 | * So we check for increased caps on the target process. | |
819 | */ | |
de45e806 | 820 | static int cap_safe_nice(struct task_struct *p) |
b5376771 | 821 | { |
f54fb863 | 822 | int is_subset, ret = 0; |
c69e8d9c DH |
823 | |
824 | rcu_read_lock(); | |
825 | is_subset = cap_issubset(__task_cred(p)->cap_permitted, | |
826 | current_cred()->cap_permitted); | |
f54fb863 SH |
827 | if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) |
828 | ret = -EPERM; | |
c69e8d9c DH |
829 | rcu_read_unlock(); |
830 | ||
f54fb863 | 831 | return ret; |
b5376771 SH |
832 | } |
833 | ||
1d045980 DH |
834 | /** |
835 | * cap_task_setscheduler - Detemine if scheduler policy change is permitted | |
836 | * @p: The task to affect | |
1d045980 DH |
837 | * |
838 | * Detemine if the requested scheduler policy change is permitted for the | |
839 | * specified task, returning 0 if permission is granted, -ve if denied. | |
840 | */ | |
b0ae1981 | 841 | int cap_task_setscheduler(struct task_struct *p) |
b5376771 SH |
842 | { |
843 | return cap_safe_nice(p); | |
844 | } | |
845 | ||
1d045980 DH |
846 | /** |
847 | * cap_task_ioprio - Detemine if I/O priority change is permitted | |
848 | * @p: The task to affect | |
849 | * @ioprio: The I/O priority to set | |
850 | * | |
851 | * Detemine if the requested I/O priority change is permitted for the specified | |
852 | * task, returning 0 if permission is granted, -ve if denied. | |
853 | */ | |
854 | int cap_task_setioprio(struct task_struct *p, int ioprio) | |
b5376771 SH |
855 | { |
856 | return cap_safe_nice(p); | |
857 | } | |
858 | ||
1d045980 DH |
859 | /** |
860 | * cap_task_ioprio - Detemine if task priority change is permitted | |
861 | * @p: The task to affect | |
862 | * @nice: The nice value to set | |
863 | * | |
864 | * Detemine if the requested task priority change is permitted for the | |
865 | * specified task, returning 0 if permission is granted, -ve if denied. | |
866 | */ | |
867 | int cap_task_setnice(struct task_struct *p, int nice) | |
b5376771 SH |
868 | { |
869 | return cap_safe_nice(p); | |
870 | } | |
871 | ||
3b7391de | 872 | /* |
1d045980 DH |
873 | * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from |
874 | * the current task's bounding set. Returns 0 on success, -ve on error. | |
3b7391de | 875 | */ |
6d6f3328 | 876 | static int cap_prctl_drop(unsigned long cap) |
3b7391de | 877 | { |
6d6f3328 TH |
878 | struct cred *new; |
879 | ||
160da84d | 880 | if (!ns_capable(current_user_ns(), CAP_SETPCAP)) |
3b7391de SH |
881 | return -EPERM; |
882 | if (!cap_valid(cap)) | |
883 | return -EINVAL; | |
d84f4f99 | 884 | |
6d6f3328 TH |
885 | new = prepare_creds(); |
886 | if (!new) | |
887 | return -ENOMEM; | |
d84f4f99 | 888 | cap_lower(new->cap_bset, cap); |
6d6f3328 | 889 | return commit_creds(new); |
3b7391de | 890 | } |
3898b1b4 | 891 | |
1d045980 DH |
892 | /** |
893 | * cap_task_prctl - Implement process control functions for this security module | |
894 | * @option: The process control function requested | |
895 | * @arg2, @arg3, @arg4, @arg5: The argument data for this function | |
896 | * | |
897 | * Allow process control functions (sys_prctl()) to alter capabilities; may | |
898 | * also deny access to other functions not otherwise implemented here. | |
899 | * | |
900 | * Returns 0 or +ve on success, -ENOSYS if this function is not implemented | |
901 | * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM | |
902 | * modules will consider performing the function. | |
903 | */ | |
3898b1b4 | 904 | int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, |
d84f4f99 | 905 | unsigned long arg4, unsigned long arg5) |
3898b1b4 | 906 | { |
6d6f3328 | 907 | const struct cred *old = current_cred(); |
d84f4f99 | 908 | struct cred *new; |
d84f4f99 | 909 | |
3898b1b4 AM |
910 | switch (option) { |
911 | case PR_CAPBSET_READ: | |
912 | if (!cap_valid(arg2)) | |
6d6f3328 TH |
913 | return -EINVAL; |
914 | return !!cap_raised(old->cap_bset, arg2); | |
d84f4f99 | 915 | |
3898b1b4 | 916 | case PR_CAPBSET_DROP: |
6d6f3328 | 917 | return cap_prctl_drop(arg2); |
3898b1b4 AM |
918 | |
919 | /* | |
920 | * The next four prctl's remain to assist with transitioning a | |
921 | * system from legacy UID=0 based privilege (when filesystem | |
922 | * capabilities are not in use) to a system using filesystem | |
923 | * capabilities only - as the POSIX.1e draft intended. | |
924 | * | |
925 | * Note: | |
926 | * | |
927 | * PR_SET_SECUREBITS = | |
928 | * issecure_mask(SECURE_KEEP_CAPS_LOCKED) | |
929 | * | issecure_mask(SECURE_NOROOT) | |
930 | * | issecure_mask(SECURE_NOROOT_LOCKED) | |
931 | * | issecure_mask(SECURE_NO_SETUID_FIXUP) | |
932 | * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) | |
933 | * | |
934 | * will ensure that the current process and all of its | |
935 | * children will be locked into a pure | |
936 | * capability-based-privilege environment. | |
937 | */ | |
938 | case PR_SET_SECUREBITS: | |
6d6f3328 TH |
939 | if ((((old->securebits & SECURE_ALL_LOCKS) >> 1) |
940 | & (old->securebits ^ arg2)) /*[1]*/ | |
941 | || ((old->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/ | |
d84f4f99 | 942 | || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ |
6a9de491 | 943 | || (cap_capable(current_cred(), |
c4a4d603 | 944 | current_cred()->user_ns, CAP_SETPCAP, |
3699c53c | 945 | SECURITY_CAP_AUDIT) != 0) /*[4]*/ |
3898b1b4 AM |
946 | /* |
947 | * [1] no changing of bits that are locked | |
948 | * [2] no unlocking of locks | |
949 | * [3] no setting of unsupported bits | |
950 | * [4] doing anything requires privilege (go read about | |
951 | * the "sendmail capabilities bug") | |
952 | */ | |
d84f4f99 DH |
953 | ) |
954 | /* cannot change a locked bit */ | |
6d6f3328 TH |
955 | return -EPERM; |
956 | ||
957 | new = prepare_creds(); | |
958 | if (!new) | |
959 | return -ENOMEM; | |
d84f4f99 | 960 | new->securebits = arg2; |
6d6f3328 | 961 | return commit_creds(new); |
d84f4f99 | 962 | |
3898b1b4 | 963 | case PR_GET_SECUREBITS: |
6d6f3328 | 964 | return old->securebits; |
3898b1b4 | 965 | |
3898b1b4 | 966 | case PR_GET_KEEPCAPS: |
6d6f3328 | 967 | return !!issecure(SECURE_KEEP_CAPS); |
d84f4f99 | 968 | |
3898b1b4 AM |
969 | case PR_SET_KEEPCAPS: |
970 | if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ | |
6d6f3328 | 971 | return -EINVAL; |
d84f4f99 | 972 | if (issecure(SECURE_KEEP_CAPS_LOCKED)) |
6d6f3328 TH |
973 | return -EPERM; |
974 | ||
975 | new = prepare_creds(); | |
976 | if (!new) | |
977 | return -ENOMEM; | |
d84f4f99 DH |
978 | if (arg2) |
979 | new->securebits |= issecure_mask(SECURE_KEEP_CAPS); | |
3898b1b4 | 980 | else |
d84f4f99 | 981 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
6d6f3328 | 982 | return commit_creds(new); |
3898b1b4 | 983 | |
58319057 AL |
984 | case PR_CAP_AMBIENT: |
985 | if (arg2 == PR_CAP_AMBIENT_CLEAR_ALL) { | |
986 | if (arg3 | arg4 | arg5) | |
987 | return -EINVAL; | |
988 | ||
989 | new = prepare_creds(); | |
990 | if (!new) | |
991 | return -ENOMEM; | |
992 | cap_clear(new->cap_ambient); | |
993 | return commit_creds(new); | |
994 | } | |
995 | ||
996 | if (((!cap_valid(arg3)) | arg4 | arg5)) | |
997 | return -EINVAL; | |
998 | ||
999 | if (arg2 == PR_CAP_AMBIENT_IS_SET) { | |
1000 | return !!cap_raised(current_cred()->cap_ambient, arg3); | |
1001 | } else if (arg2 != PR_CAP_AMBIENT_RAISE && | |
1002 | arg2 != PR_CAP_AMBIENT_LOWER) { | |
1003 | return -EINVAL; | |
1004 | } else { | |
1005 | if (arg2 == PR_CAP_AMBIENT_RAISE && | |
1006 | (!cap_raised(current_cred()->cap_permitted, arg3) || | |
1007 | !cap_raised(current_cred()->cap_inheritable, | |
746bf6d6 AL |
1008 | arg3) || |
1009 | issecure(SECURE_NO_CAP_AMBIENT_RAISE))) | |
58319057 AL |
1010 | return -EPERM; |
1011 | ||
1012 | new = prepare_creds(); | |
1013 | if (!new) | |
1014 | return -ENOMEM; | |
1015 | if (arg2 == PR_CAP_AMBIENT_RAISE) | |
1016 | cap_raise(new->cap_ambient, arg3); | |
1017 | else | |
1018 | cap_lower(new->cap_ambient, arg3); | |
1019 | return commit_creds(new); | |
1020 | } | |
1021 | ||
3898b1b4 AM |
1022 | default: |
1023 | /* No functionality available - continue with default */ | |
6d6f3328 | 1024 | return -ENOSYS; |
3898b1b4 | 1025 | } |
1da177e4 LT |
1026 | } |
1027 | ||
1d045980 DH |
1028 | /** |
1029 | * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted | |
1030 | * @mm: The VM space in which the new mapping is to be made | |
1031 | * @pages: The size of the mapping | |
1032 | * | |
1033 | * Determine whether the allocation of a new virtual mapping by the current | |
b1d9e6b0 | 1034 | * task is permitted, returning 1 if permission is granted, 0 if not. |
1d045980 | 1035 | */ |
34b4e4aa | 1036 | int cap_vm_enough_memory(struct mm_struct *mm, long pages) |
1da177e4 LT |
1037 | { |
1038 | int cap_sys_admin = 0; | |
1039 | ||
6a9de491 | 1040 | if (cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN, |
3699c53c | 1041 | SECURITY_CAP_NOAUDIT) == 0) |
1da177e4 | 1042 | cap_sys_admin = 1; |
b1d9e6b0 | 1043 | return cap_sys_admin; |
1da177e4 | 1044 | } |
7c73875e EP |
1045 | |
1046 | /* | |
d007794a | 1047 | * cap_mmap_addr - check if able to map given addr |
7c73875e | 1048 | * @addr: address attempting to be mapped |
7c73875e | 1049 | * |
6f262d8e | 1050 | * If the process is attempting to map memory below dac_mmap_min_addr they need |
7c73875e EP |
1051 | * CAP_SYS_RAWIO. The other parameters to this function are unused by the |
1052 | * capability security module. Returns 0 if this mapping should be allowed | |
1053 | * -EPERM if not. | |
1054 | */ | |
d007794a | 1055 | int cap_mmap_addr(unsigned long addr) |
7c73875e EP |
1056 | { |
1057 | int ret = 0; | |
1058 | ||
a2551df7 | 1059 | if (addr < dac_mmap_min_addr) { |
6a9de491 | 1060 | ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO, |
7c73875e EP |
1061 | SECURITY_CAP_AUDIT); |
1062 | /* set PF_SUPERPRIV if it turns out we allow the low mmap */ | |
1063 | if (ret == 0) | |
1064 | current->flags |= PF_SUPERPRIV; | |
1065 | } | |
1066 | return ret; | |
1067 | } | |
d007794a | 1068 | |
e5467859 AV |
1069 | int cap_mmap_file(struct file *file, unsigned long reqprot, |
1070 | unsigned long prot, unsigned long flags) | |
d007794a | 1071 | { |
e5467859 | 1072 | return 0; |
d007794a | 1073 | } |
b1d9e6b0 CS |
1074 | |
1075 | #ifdef CONFIG_SECURITY | |
1076 | ||
ca97d939 | 1077 | struct security_hook_list capability_hooks[] __lsm_ro_after_init = { |
b1d9e6b0 CS |
1078 | LSM_HOOK_INIT(capable, cap_capable), |
1079 | LSM_HOOK_INIT(settime, cap_settime), | |
1080 | LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check), | |
1081 | LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme), | |
1082 | LSM_HOOK_INIT(capget, cap_capget), | |
1083 | LSM_HOOK_INIT(capset, cap_capset), | |
1084 | LSM_HOOK_INIT(bprm_set_creds, cap_bprm_set_creds), | |
1085 | LSM_HOOK_INIT(bprm_secureexec, cap_bprm_secureexec), | |
1086 | LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv), | |
1087 | LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv), | |
1088 | LSM_HOOK_INIT(mmap_addr, cap_mmap_addr), | |
1089 | LSM_HOOK_INIT(mmap_file, cap_mmap_file), | |
1090 | LSM_HOOK_INIT(task_fix_setuid, cap_task_fix_setuid), | |
1091 | LSM_HOOK_INIT(task_prctl, cap_task_prctl), | |
1092 | LSM_HOOK_INIT(task_setscheduler, cap_task_setscheduler), | |
1093 | LSM_HOOK_INIT(task_setioprio, cap_task_setioprio), | |
1094 | LSM_HOOK_INIT(task_setnice, cap_task_setnice), | |
1095 | LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory), | |
1096 | }; | |
1097 | ||
1098 | void __init capability_add_hooks(void) | |
1099 | { | |
d69dece5 CS |
1100 | security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks), |
1101 | "capability"); | |
b1d9e6b0 CS |
1102 | } |
1103 | ||
1104 | #endif /* CONFIG_SECURITY */ |