Commit | Line | Data |
---|---|---|
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 | ||
85 | /* Have we tried all of the parent namespaces? */ | |
520d9eab | 86 | if (ns == &init_user_ns) |
3486740a SH |
87 | return -EPERM; |
88 | ||
520d9eab EB |
89 | /* |
90 | * The owner of the user namespace in the parent of the | |
91 | * user namespace has all caps. | |
92 | */ | |
93 | if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid)) | |
94 | return 0; | |
95 | ||
3486740a | 96 | /* |
520d9eab | 97 | * If you have a capability in a parent user ns, then you have |
3486740a SH |
98 | * it over all children user namespaces as well. |
99 | */ | |
520d9eab | 100 | ns = ns->parent; |
3486740a SH |
101 | } |
102 | ||
103 | /* We never get here */ | |
1da177e4 LT |
104 | } |
105 | ||
1d045980 DH |
106 | /** |
107 | * cap_settime - Determine whether the current process may set the system clock | |
108 | * @ts: The time to set | |
109 | * @tz: The timezone to set | |
110 | * | |
111 | * Determine whether the current process may set the system clock and timezone | |
112 | * information, returning 0 if permission granted, -ve if denied. | |
113 | */ | |
1e6d7679 | 114 | int cap_settime(const struct timespec *ts, const struct timezone *tz) |
1da177e4 LT |
115 | { |
116 | if (!capable(CAP_SYS_TIME)) | |
117 | return -EPERM; | |
118 | return 0; | |
119 | } | |
120 | ||
1d045980 | 121 | /** |
9e48858f | 122 | * cap_ptrace_access_check - Determine whether the current process may access |
1d045980 DH |
123 | * another |
124 | * @child: The process to be accessed | |
125 | * @mode: The mode of attachment. | |
126 | * | |
8409cca7 SH |
127 | * If we are in the same or an ancestor user_ns and have all the target |
128 | * task's capabilities, then ptrace access is allowed. | |
129 | * If we have the ptrace capability to the target user_ns, then ptrace | |
130 | * access is allowed. | |
131 | * Else denied. | |
132 | * | |
1d045980 DH |
133 | * Determine whether a process may access another, returning 0 if permission |
134 | * granted, -ve if denied. | |
135 | */ | |
9e48858f | 136 | int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) |
1da177e4 | 137 | { |
c69e8d9c | 138 | int ret = 0; |
8409cca7 | 139 | const struct cred *cred, *child_cred; |
c69e8d9c DH |
140 | |
141 | rcu_read_lock(); | |
8409cca7 SH |
142 | cred = current_cred(); |
143 | child_cred = __task_cred(child); | |
c4a4d603 | 144 | if (cred->user_ns == child_cred->user_ns && |
8409cca7 SH |
145 | cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) |
146 | goto out; | |
c4a4d603 | 147 | if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
148 | goto out; |
149 | ret = -EPERM; | |
150 | out: | |
c69e8d9c DH |
151 | rcu_read_unlock(); |
152 | return ret; | |
5cd9c58f DH |
153 | } |
154 | ||
1d045980 DH |
155 | /** |
156 | * cap_ptrace_traceme - Determine whether another process may trace the current | |
157 | * @parent: The task proposed to be the tracer | |
158 | * | |
8409cca7 SH |
159 | * If parent is in the same or an ancestor user_ns and has all current's |
160 | * capabilities, then ptrace access is allowed. | |
161 | * If parent has the ptrace capability to current's user_ns, then ptrace | |
162 | * access is allowed. | |
163 | * Else denied. | |
164 | * | |
1d045980 DH |
165 | * Determine whether the nominated task is permitted to trace the current |
166 | * process, returning 0 if permission is granted, -ve if denied. | |
167 | */ | |
5cd9c58f DH |
168 | int cap_ptrace_traceme(struct task_struct *parent) |
169 | { | |
c69e8d9c | 170 | int ret = 0; |
8409cca7 | 171 | const struct cred *cred, *child_cred; |
c69e8d9c DH |
172 | |
173 | rcu_read_lock(); | |
8409cca7 SH |
174 | cred = __task_cred(parent); |
175 | child_cred = current_cred(); | |
c4a4d603 | 176 | if (cred->user_ns == child_cred->user_ns && |
8409cca7 SH |
177 | cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) |
178 | goto out; | |
c4a4d603 | 179 | if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE)) |
8409cca7 SH |
180 | goto out; |
181 | ret = -EPERM; | |
182 | out: | |
c69e8d9c DH |
183 | rcu_read_unlock(); |
184 | return ret; | |
1da177e4 LT |
185 | } |
186 | ||
1d045980 DH |
187 | /** |
188 | * cap_capget - Retrieve a task's capability sets | |
189 | * @target: The task from which to retrieve the capability sets | |
190 | * @effective: The place to record the effective set | |
191 | * @inheritable: The place to record the inheritable set | |
192 | * @permitted: The place to record the permitted set | |
193 | * | |
194 | * This function retrieves the capabilities of the nominated task and returns | |
195 | * them to the caller. | |
196 | */ | |
197 | int cap_capget(struct task_struct *target, kernel_cap_t *effective, | |
198 | kernel_cap_t *inheritable, kernel_cap_t *permitted) | |
1da177e4 | 199 | { |
c69e8d9c | 200 | const struct cred *cred; |
b6dff3ec | 201 | |
1da177e4 | 202 | /* Derived from kernel/capability.c:sys_capget. */ |
c69e8d9c DH |
203 | rcu_read_lock(); |
204 | cred = __task_cred(target); | |
b6dff3ec DH |
205 | *effective = cred->cap_effective; |
206 | *inheritable = cred->cap_inheritable; | |
207 | *permitted = cred->cap_permitted; | |
c69e8d9c | 208 | rcu_read_unlock(); |
1da177e4 LT |
209 | return 0; |
210 | } | |
211 | ||
1d045980 DH |
212 | /* |
213 | * Determine whether the inheritable capabilities are limited to the old | |
214 | * permitted set. Returns 1 if they are limited, 0 if they are not. | |
215 | */ | |
72c2d582 AM |
216 | static inline int cap_inh_is_capped(void) |
217 | { | |
72c2d582 | 218 | |
1d045980 DH |
219 | /* they are so limited unless the current task has the CAP_SETPCAP |
220 | * capability | |
221 | */ | |
c4a4d603 | 222 | if (cap_capable(current_cred(), current_cred()->user_ns, |
6a9de491 | 223 | CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0) |
1d045980 | 224 | return 0; |
1d045980 | 225 | return 1; |
1209726c | 226 | } |
72c2d582 | 227 | |
1d045980 DH |
228 | /** |
229 | * cap_capset - Validate and apply proposed changes to current's capabilities | |
230 | * @new: The proposed new credentials; alterations should be made here | |
231 | * @old: The current task's current credentials | |
232 | * @effective: A pointer to the proposed new effective capabilities set | |
233 | * @inheritable: A pointer to the proposed new inheritable capabilities set | |
234 | * @permitted: A pointer to the proposed new permitted capabilities set | |
235 | * | |
236 | * This function validates and applies a proposed mass change to the current | |
237 | * process's capability sets. The changes are made to the proposed new | |
238 | * credentials, and assuming no error, will be committed by the caller of LSM. | |
239 | */ | |
d84f4f99 DH |
240 | int cap_capset(struct cred *new, |
241 | const struct cred *old, | |
242 | const kernel_cap_t *effective, | |
243 | const kernel_cap_t *inheritable, | |
244 | const kernel_cap_t *permitted) | |
1da177e4 | 245 | { |
d84f4f99 DH |
246 | if (cap_inh_is_capped() && |
247 | !cap_issubset(*inheritable, | |
248 | cap_combine(old->cap_inheritable, | |
249 | old->cap_permitted))) | |
72c2d582 | 250 | /* incapable of using this inheritable set */ |
1da177e4 | 251 | return -EPERM; |
d84f4f99 | 252 | |
3b7391de | 253 | if (!cap_issubset(*inheritable, |
d84f4f99 DH |
254 | cap_combine(old->cap_inheritable, |
255 | old->cap_bset))) | |
3b7391de SH |
256 | /* no new pI capabilities outside bounding set */ |
257 | return -EPERM; | |
1da177e4 LT |
258 | |
259 | /* verify restrictions on target's new Permitted set */ | |
d84f4f99 | 260 | if (!cap_issubset(*permitted, old->cap_permitted)) |
1da177e4 | 261 | return -EPERM; |
1da177e4 LT |
262 | |
263 | /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ | |
d84f4f99 | 264 | if (!cap_issubset(*effective, *permitted)) |
1da177e4 | 265 | return -EPERM; |
1da177e4 | 266 | |
d84f4f99 DH |
267 | new->cap_effective = *effective; |
268 | new->cap_inheritable = *inheritable; | |
269 | new->cap_permitted = *permitted; | |
58319057 AL |
270 | |
271 | /* | |
272 | * Mask off ambient bits that are no longer both permitted and | |
273 | * inheritable. | |
274 | */ | |
275 | new->cap_ambient = cap_intersect(new->cap_ambient, | |
276 | cap_intersect(*permitted, | |
277 | *inheritable)); | |
278 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
279 | return -EINVAL; | |
1da177e4 LT |
280 | return 0; |
281 | } | |
282 | ||
1d045980 DH |
283 | /* |
284 | * Clear proposed capability sets for execve(). | |
285 | */ | |
b5376771 SH |
286 | static inline void bprm_clear_caps(struct linux_binprm *bprm) |
287 | { | |
a6f76f23 | 288 | cap_clear(bprm->cred->cap_permitted); |
b5376771 SH |
289 | bprm->cap_effective = false; |
290 | } | |
291 | ||
1d045980 DH |
292 | /** |
293 | * cap_inode_need_killpriv - Determine if inode change affects privileges | |
294 | * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV | |
295 | * | |
296 | * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV | |
297 | * affects the security markings on that inode, and if it is, should | |
298 | * inode_killpriv() be invoked or the change rejected? | |
299 | * | |
300 | * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and | |
301 | * -ve to deny the change. | |
302 | */ | |
b5376771 SH |
303 | int cap_inode_need_killpriv(struct dentry *dentry) |
304 | { | |
c6f493d6 | 305 | struct inode *inode = d_backing_inode(dentry); |
b5376771 SH |
306 | int error; |
307 | ||
acfa4380 | 308 | if (!inode->i_op->getxattr) |
b5376771 SH |
309 | return 0; |
310 | ||
311 | error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0); | |
312 | if (error <= 0) | |
313 | return 0; | |
314 | return 1; | |
315 | } | |
316 | ||
1d045980 DH |
317 | /** |
318 | * cap_inode_killpriv - Erase the security markings on an inode | |
319 | * @dentry: The inode/dentry to alter | |
320 | * | |
321 | * Erase the privilege-enhancing security markings on an inode. | |
322 | * | |
323 | * Returns 0 if successful, -ve on error. | |
324 | */ | |
b5376771 SH |
325 | int cap_inode_killpriv(struct dentry *dentry) |
326 | { | |
c6f493d6 | 327 | struct inode *inode = d_backing_inode(dentry); |
b5376771 | 328 | |
acfa4380 | 329 | if (!inode->i_op->removexattr) |
b5376771 SH |
330 | return 0; |
331 | ||
332 | return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS); | |
333 | } | |
334 | ||
1d045980 DH |
335 | /* |
336 | * Calculate the new process capability sets from the capability sets attached | |
337 | * to a file. | |
338 | */ | |
c0b00441 | 339 | static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, |
a6f76f23 | 340 | struct linux_binprm *bprm, |
4d49f671 ZL |
341 | bool *effective, |
342 | bool *has_cap) | |
b5376771 | 343 | { |
a6f76f23 | 344 | struct cred *new = bprm->cred; |
c0b00441 EP |
345 | unsigned i; |
346 | int ret = 0; | |
347 | ||
348 | if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) | |
a6f76f23 | 349 | *effective = true; |
c0b00441 | 350 | |
4d49f671 ZL |
351 | if (caps->magic_etc & VFS_CAP_REVISION_MASK) |
352 | *has_cap = true; | |
353 | ||
c0b00441 EP |
354 | CAP_FOR_EACH_U32(i) { |
355 | __u32 permitted = caps->permitted.cap[i]; | |
356 | __u32 inheritable = caps->inheritable.cap[i]; | |
357 | ||
358 | /* | |
359 | * pP' = (X & fP) | (pI & fI) | |
58319057 | 360 | * The addition of pA' is handled later. |
c0b00441 | 361 | */ |
a6f76f23 DH |
362 | new->cap_permitted.cap[i] = |
363 | (new->cap_bset.cap[i] & permitted) | | |
364 | (new->cap_inheritable.cap[i] & inheritable); | |
c0b00441 | 365 | |
a6f76f23 DH |
366 | if (permitted & ~new->cap_permitted.cap[i]) |
367 | /* insufficient to execute correctly */ | |
c0b00441 | 368 | ret = -EPERM; |
c0b00441 EP |
369 | } |
370 | ||
371 | /* | |
372 | * For legacy apps, with no internal support for recognizing they | |
373 | * do not have enough capabilities, we return an error if they are | |
374 | * missing some "forced" (aka file-permitted) capabilities. | |
375 | */ | |
a6f76f23 | 376 | return *effective ? ret : 0; |
c0b00441 EP |
377 | } |
378 | ||
1d045980 DH |
379 | /* |
380 | * Extract the on-exec-apply capability sets for an executable file. | |
381 | */ | |
c0b00441 EP |
382 | int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) |
383 | { | |
c6f493d6 | 384 | struct inode *inode = d_backing_inode(dentry); |
b5376771 | 385 | __u32 magic_etc; |
e338d263 | 386 | unsigned tocopy, i; |
c0b00441 EP |
387 | int size; |
388 | struct vfs_cap_data caps; | |
389 | ||
390 | memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); | |
391 | ||
acfa4380 | 392 | if (!inode || !inode->i_op->getxattr) |
c0b00441 EP |
393 | return -ENODATA; |
394 | ||
395 | size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps, | |
396 | XATTR_CAPS_SZ); | |
a6f76f23 | 397 | if (size == -ENODATA || size == -EOPNOTSUPP) |
c0b00441 EP |
398 | /* no data, that's ok */ |
399 | return -ENODATA; | |
c0b00441 EP |
400 | if (size < 0) |
401 | return size; | |
b5376771 | 402 | |
e338d263 | 403 | if (size < sizeof(magic_etc)) |
b5376771 SH |
404 | return -EINVAL; |
405 | ||
c0b00441 | 406 | cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc); |
b5376771 | 407 | |
a6f76f23 | 408 | switch (magic_etc & VFS_CAP_REVISION_MASK) { |
e338d263 AM |
409 | case VFS_CAP_REVISION_1: |
410 | if (size != XATTR_CAPS_SZ_1) | |
411 | return -EINVAL; | |
412 | tocopy = VFS_CAP_U32_1; | |
413 | break; | |
414 | case VFS_CAP_REVISION_2: | |
415 | if (size != XATTR_CAPS_SZ_2) | |
416 | return -EINVAL; | |
417 | tocopy = VFS_CAP_U32_2; | |
418 | break; | |
b5376771 SH |
419 | default: |
420 | return -EINVAL; | |
421 | } | |
e338d263 | 422 | |
5459c164 | 423 | CAP_FOR_EACH_U32(i) { |
c0b00441 EP |
424 | if (i >= tocopy) |
425 | break; | |
426 | cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted); | |
427 | cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable); | |
e338d263 | 428 | } |
a6f76f23 | 429 | |
7d8b6c63 EP |
430 | cpu_caps->permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; |
431 | cpu_caps->inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK; | |
432 | ||
c0b00441 | 433 | return 0; |
b5376771 SH |
434 | } |
435 | ||
1d045980 DH |
436 | /* |
437 | * Attempt to get the on-exec apply capability sets for an executable file from | |
438 | * its xattrs and, if present, apply them to the proposed credentials being | |
439 | * constructed by execve(). | |
440 | */ | |
4d49f671 | 441 | static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_cap) |
b5376771 | 442 | { |
b5376771 | 443 | int rc = 0; |
c0b00441 | 444 | struct cpu_vfs_cap_data vcaps; |
b5376771 | 445 | |
3318a386 SH |
446 | bprm_clear_caps(bprm); |
447 | ||
1f29fae2 SH |
448 | if (!file_caps_enabled) |
449 | return 0; | |
450 | ||
182be684 | 451 | if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) |
b5376771 | 452 | return 0; |
b5376771 | 453 | |
f4a4a8b1 | 454 | rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps); |
c0b00441 EP |
455 | if (rc < 0) { |
456 | if (rc == -EINVAL) | |
457 | printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n", | |
458 | __func__, rc, bprm->filename); | |
459 | else if (rc == -ENODATA) | |
460 | rc = 0; | |
b5376771 SH |
461 | goto out; |
462 | } | |
b5376771 | 463 | |
4d49f671 | 464 | rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective, has_cap); |
a6f76f23 DH |
465 | if (rc == -EINVAL) |
466 | printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n", | |
467 | __func__, rc, bprm->filename); | |
b5376771 SH |
468 | |
469 | out: | |
b5376771 SH |
470 | if (rc) |
471 | bprm_clear_caps(bprm); | |
472 | ||
473 | return rc; | |
474 | } | |
475 | ||
1d045980 DH |
476 | /** |
477 | * cap_bprm_set_creds - Set up the proposed credentials for execve(). | |
478 | * @bprm: The execution parameters, including the proposed creds | |
479 | * | |
480 | * Set up the proposed credentials for a new execution context being | |
481 | * constructed by execve(). The proposed creds in @bprm->cred is altered, | |
482 | * which won't take effect immediately. Returns 0 if successful, -ve on error. | |
a6f76f23 DH |
483 | */ |
484 | int cap_bprm_set_creds(struct linux_binprm *bprm) | |
1da177e4 | 485 | { |
a6f76f23 DH |
486 | const struct cred *old = current_cred(); |
487 | struct cred *new = bprm->cred; | |
58319057 | 488 | bool effective, has_cap = false, is_setid; |
b5376771 | 489 | int ret; |
18815a18 | 490 | kuid_t root_uid; |
1da177e4 | 491 | |
58319057 AL |
492 | if (WARN_ON(!cap_ambient_invariant_ok(old))) |
493 | return -EPERM; | |
494 | ||
a6f76f23 | 495 | effective = false; |
4d49f671 | 496 | ret = get_file_caps(bprm, &effective, &has_cap); |
a6f76f23 DH |
497 | if (ret < 0) |
498 | return ret; | |
1da177e4 | 499 | |
18815a18 EB |
500 | root_uid = make_kuid(new->user_ns, 0); |
501 | ||
5459c164 | 502 | if (!issecure(SECURE_NOROOT)) { |
b5f22a59 SH |
503 | /* |
504 | * If the legacy file capability is set, then don't set privs | |
505 | * for a setuid root binary run by a non-root user. Do set it | |
506 | * for a root user just to cause least surprise to an admin. | |
507 | */ | |
18815a18 | 508 | if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { |
b5f22a59 SH |
509 | warn_setuid_and_fcaps_mixed(bprm->filename); |
510 | goto skip; | |
511 | } | |
5459c164 AM |
512 | /* |
513 | * To support inheritance of root-permissions and suid-root | |
514 | * executables under compatibility mode, we override the | |
515 | * capability sets for the file. | |
516 | * | |
a6f76f23 | 517 | * If only the real uid is 0, we do not set the effective bit. |
5459c164 | 518 | */ |
18815a18 | 519 | if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { |
5459c164 | 520 | /* pP' = (cap_bset & ~0) | (pI & ~0) */ |
a6f76f23 DH |
521 | new->cap_permitted = cap_combine(old->cap_bset, |
522 | old->cap_inheritable); | |
1da177e4 | 523 | } |
18815a18 | 524 | if (uid_eq(new->euid, root_uid)) |
a6f76f23 | 525 | effective = true; |
1da177e4 | 526 | } |
b5f22a59 | 527 | skip: |
b5376771 | 528 | |
d52fc5dd EP |
529 | /* if we have fs caps, clear dangerous personality flags */ |
530 | if (!cap_issubset(new->cap_permitted, old->cap_permitted)) | |
531 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
532 | ||
533 | ||
a6f76f23 | 534 | /* Don't let someone trace a set[ug]id/setpcap binary with the revised |
259e5e6c AL |
535 | * credentials unless they have the appropriate permit. |
536 | * | |
537 | * In addition, if NO_NEW_PRIVS, then ensure we get no new privs. | |
a6f76f23 | 538 | */ |
58319057 AL |
539 | is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid); |
540 | ||
541 | if ((is_setid || | |
a6f76f23 DH |
542 | !cap_issubset(new->cap_permitted, old->cap_permitted)) && |
543 | bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) { | |
544 | /* downgrade; they get no more than they had, and maybe less */ | |
259e5e6c AL |
545 | if (!capable(CAP_SETUID) || |
546 | (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) { | |
a6f76f23 DH |
547 | new->euid = new->uid; |
548 | new->egid = new->gid; | |
1da177e4 | 549 | } |
b3a222e5 SH |
550 | new->cap_permitted = cap_intersect(new->cap_permitted, |
551 | old->cap_permitted); | |
1da177e4 LT |
552 | } |
553 | ||
a6f76f23 DH |
554 | new->suid = new->fsuid = new->euid; |
555 | new->sgid = new->fsgid = new->egid; | |
1da177e4 | 556 | |
58319057 AL |
557 | /* File caps or setid cancels ambient. */ |
558 | if (has_cap || is_setid) | |
559 | cap_clear(new->cap_ambient); | |
560 | ||
561 | /* | |
562 | * Now that we've computed pA', update pP' to give: | |
563 | * pP' = (X & fP) | (pI & fI) | pA' | |
564 | */ | |
565 | new->cap_permitted = cap_combine(new->cap_permitted, new->cap_ambient); | |
566 | ||
567 | /* | |
568 | * Set pE' = (fE ? pP' : pA'). Because pA' is zero if fE is set, | |
569 | * this is the same as pE' = (fE ? pP' : 0) | pA'. | |
570 | */ | |
4bf2ea77 EP |
571 | if (effective) |
572 | new->cap_effective = new->cap_permitted; | |
573 | else | |
58319057 AL |
574 | new->cap_effective = new->cap_ambient; |
575 | ||
576 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
577 | return -EPERM; | |
578 | ||
a6f76f23 | 579 | bprm->cap_effective = effective; |
1da177e4 | 580 | |
3fc689e9 EP |
581 | /* |
582 | * Audit candidate if current->cap_effective is set | |
583 | * | |
584 | * We do not bother to audit if 3 things are true: | |
585 | * 1) cap_effective has all caps | |
586 | * 2) we are root | |
587 | * 3) root is supposed to have all caps (SECURE_NOROOT) | |
588 | * Since this is just a normal root execing a process. | |
589 | * | |
590 | * Number 1 above might fail if you don't have a full bset, but I think | |
591 | * that is interesting information to audit. | |
592 | */ | |
58319057 | 593 | if (!cap_issubset(new->cap_effective, new->cap_ambient)) { |
d84f4f99 | 594 | if (!cap_issubset(CAP_FULL_SET, new->cap_effective) || |
18815a18 | 595 | !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) || |
a6f76f23 DH |
596 | issecure(SECURE_NOROOT)) { |
597 | ret = audit_log_bprm_fcaps(bprm, new, old); | |
598 | if (ret < 0) | |
599 | return ret; | |
600 | } | |
3fc689e9 | 601 | } |
1da177e4 | 602 | |
d84f4f99 | 603 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
58319057 AL |
604 | |
605 | if (WARN_ON(!cap_ambient_invariant_ok(new))) | |
606 | return -EPERM; | |
607 | ||
a6f76f23 | 608 | return 0; |
1da177e4 LT |
609 | } |
610 | ||
1d045980 DH |
611 | /** |
612 | * cap_bprm_secureexec - Determine whether a secure execution is required | |
613 | * @bprm: The execution parameters | |
614 | * | |
615 | * Determine whether a secure execution is required, return 1 if it is, and 0 | |
616 | * if it is not. | |
617 | * | |
618 | * The credentials have been committed by this point, and so are no longer | |
619 | * available through @bprm->cred. | |
a6f76f23 DH |
620 | */ |
621 | int cap_bprm_secureexec(struct linux_binprm *bprm) | |
1da177e4 | 622 | { |
c69e8d9c | 623 | const struct cred *cred = current_cred(); |
18815a18 | 624 | kuid_t root_uid = make_kuid(cred->user_ns, 0); |
b6dff3ec | 625 | |
18815a18 | 626 | if (!uid_eq(cred->uid, root_uid)) { |
b5376771 SH |
627 | if (bprm->cap_effective) |
628 | return 1; | |
58319057 | 629 | if (!cap_issubset(cred->cap_permitted, cred->cap_ambient)) |
b5376771 SH |
630 | return 1; |
631 | } | |
632 | ||
18815a18 EB |
633 | return (!uid_eq(cred->euid, cred->uid) || |
634 | !gid_eq(cred->egid, cred->gid)); | |
1da177e4 LT |
635 | } |
636 | ||
1d045980 DH |
637 | /** |
638 | * cap_inode_setxattr - Determine whether an xattr may be altered | |
639 | * @dentry: The inode/dentry being altered | |
640 | * @name: The name of the xattr to be changed | |
641 | * @value: The value that the xattr will be changed to | |
642 | * @size: The size of value | |
643 | * @flags: The replacement flag | |
644 | * | |
645 | * Determine whether an xattr may be altered or set on an inode, returning 0 if | |
646 | * permission is granted, -ve if denied. | |
647 | * | |
648 | * This is used to make sure security xattrs don't get updated or set by those | |
649 | * who aren't privileged to do so. | |
650 | */ | |
8f0cfa52 DH |
651 | int cap_inode_setxattr(struct dentry *dentry, const char *name, |
652 | const void *value, size_t size, int flags) | |
1da177e4 | 653 | { |
b5376771 SH |
654 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
655 | if (!capable(CAP_SETFCAP)) | |
656 | return -EPERM; | |
657 | return 0; | |
1d045980 DH |
658 | } |
659 | ||
660 | if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
c5b60b5e | 661 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
1da177e4 LT |
662 | !capable(CAP_SYS_ADMIN)) |
663 | return -EPERM; | |
664 | return 0; | |
665 | } | |
666 | ||
1d045980 DH |
667 | /** |
668 | * cap_inode_removexattr - Determine whether an xattr may be removed | |
669 | * @dentry: The inode/dentry being altered | |
670 | * @name: The name of the xattr to be changed | |
671 | * | |
672 | * Determine whether an xattr may be removed from an inode, returning 0 if | |
673 | * permission is granted, -ve if denied. | |
674 | * | |
675 | * This is used to make sure security xattrs don't get removed by those who | |
676 | * aren't privileged to remove them. | |
677 | */ | |
8f0cfa52 | 678 | int cap_inode_removexattr(struct dentry *dentry, const char *name) |
1da177e4 | 679 | { |
b5376771 SH |
680 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
681 | if (!capable(CAP_SETFCAP)) | |
682 | return -EPERM; | |
683 | return 0; | |
1d045980 DH |
684 | } |
685 | ||
686 | if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
c5b60b5e | 687 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
1da177e4 LT |
688 | !capable(CAP_SYS_ADMIN)) |
689 | return -EPERM; | |
690 | return 0; | |
691 | } | |
692 | ||
a6f76f23 | 693 | /* |
1da177e4 LT |
694 | * cap_emulate_setxuid() fixes the effective / permitted capabilities of |
695 | * a process after a call to setuid, setreuid, or setresuid. | |
696 | * | |
697 | * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of | |
698 | * {r,e,s}uid != 0, the permitted and effective capabilities are | |
699 | * cleared. | |
700 | * | |
701 | * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective | |
702 | * capabilities of the process are cleared. | |
703 | * | |
704 | * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective | |
705 | * capabilities are set to the permitted capabilities. | |
706 | * | |
a6f76f23 | 707 | * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should |
1da177e4 LT |
708 | * never happen. |
709 | * | |
a6f76f23 | 710 | * -astor |
1da177e4 LT |
711 | * |
712 | * cevans - New behaviour, Oct '99 | |
713 | * A process may, via prctl(), elect to keep its capabilities when it | |
714 | * calls setuid() and switches away from uid==0. Both permitted and | |
715 | * effective sets will be retained. | |
716 | * Without this change, it was impossible for a daemon to drop only some | |
717 | * of its privilege. The call to setuid(!=0) would drop all privileges! | |
718 | * Keeping uid 0 is not an option because uid 0 owns too many vital | |
719 | * files.. | |
720 | * Thanks to Olaf Kirch and Peter Benie for spotting this. | |
721 | */ | |
d84f4f99 | 722 | static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old) |
1da177e4 | 723 | { |
18815a18 EB |
724 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
725 | ||
726 | if ((uid_eq(old->uid, root_uid) || | |
727 | uid_eq(old->euid, root_uid) || | |
728 | uid_eq(old->suid, root_uid)) && | |
729 | (!uid_eq(new->uid, root_uid) && | |
730 | !uid_eq(new->euid, root_uid) && | |
58319057 AL |
731 | !uid_eq(new->suid, root_uid))) { |
732 | if (!issecure(SECURE_KEEP_CAPS)) { | |
733 | cap_clear(new->cap_permitted); | |
734 | cap_clear(new->cap_effective); | |
735 | } | |
736 | ||
737 | /* | |
738 | * Pre-ambient programs expect setresuid to nonroot followed | |
739 | * by exec to drop capabilities. We should make sure that | |
740 | * this remains the case. | |
741 | */ | |
742 | cap_clear(new->cap_ambient); | |
1da177e4 | 743 | } |
18815a18 | 744 | if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid)) |
d84f4f99 | 745 | cap_clear(new->cap_effective); |
18815a18 | 746 | if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid)) |
d84f4f99 | 747 | new->cap_effective = new->cap_permitted; |
1da177e4 LT |
748 | } |
749 | ||
1d045980 DH |
750 | /** |
751 | * cap_task_fix_setuid - Fix up the results of setuid() call | |
752 | * @new: The proposed credentials | |
753 | * @old: The current task's current credentials | |
754 | * @flags: Indications of what has changed | |
755 | * | |
756 | * Fix up the results of setuid() call before the credential changes are | |
757 | * actually applied, returning 0 to grant the changes, -ve to deny them. | |
758 | */ | |
d84f4f99 | 759 | int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) |
1da177e4 LT |
760 | { |
761 | switch (flags) { | |
762 | case LSM_SETID_RE: | |
763 | case LSM_SETID_ID: | |
764 | case LSM_SETID_RES: | |
1d045980 DH |
765 | /* juggle the capabilities to follow [RES]UID changes unless |
766 | * otherwise suppressed */ | |
d84f4f99 DH |
767 | if (!issecure(SECURE_NO_SETUID_FIXUP)) |
768 | cap_emulate_setxuid(new, old); | |
1da177e4 | 769 | break; |
1da177e4 | 770 | |
1d045980 DH |
771 | case LSM_SETID_FS: |
772 | /* juggle the capabilties to follow FSUID changes, unless | |
773 | * otherwise suppressed | |
774 | * | |
d84f4f99 DH |
775 | * FIXME - is fsuser used for all CAP_FS_MASK capabilities? |
776 | * if not, we might be a bit too harsh here. | |
777 | */ | |
778 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { | |
18815a18 EB |
779 | kuid_t root_uid = make_kuid(old->user_ns, 0); |
780 | if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid)) | |
d84f4f99 DH |
781 | new->cap_effective = |
782 | cap_drop_fs_set(new->cap_effective); | |
1d045980 | 783 | |
18815a18 | 784 | if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid)) |
d84f4f99 DH |
785 | new->cap_effective = |
786 | cap_raise_fs_set(new->cap_effective, | |
787 | new->cap_permitted); | |
1da177e4 | 788 | } |
d84f4f99 | 789 | break; |
1d045980 | 790 | |
1da177e4 LT |
791 | default: |
792 | return -EINVAL; | |
793 | } | |
794 | ||
795 | return 0; | |
796 | } | |
797 | ||
b5376771 SH |
798 | /* |
799 | * Rationale: code calling task_setscheduler, task_setioprio, and | |
800 | * task_setnice, assumes that | |
801 | * . if capable(cap_sys_nice), then those actions should be allowed | |
802 | * . if not capable(cap_sys_nice), but acting on your own processes, | |
803 | * then those actions should be allowed | |
804 | * This is insufficient now since you can call code without suid, but | |
805 | * yet with increased caps. | |
806 | * So we check for increased caps on the target process. | |
807 | */ | |
de45e806 | 808 | static int cap_safe_nice(struct task_struct *p) |
b5376771 | 809 | { |
f54fb863 | 810 | int is_subset, ret = 0; |
c69e8d9c DH |
811 | |
812 | rcu_read_lock(); | |
813 | is_subset = cap_issubset(__task_cred(p)->cap_permitted, | |
814 | current_cred()->cap_permitted); | |
f54fb863 SH |
815 | if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) |
816 | ret = -EPERM; | |
c69e8d9c DH |
817 | rcu_read_unlock(); |
818 | ||
f54fb863 | 819 | return ret; |
b5376771 SH |
820 | } |
821 | ||
1d045980 DH |
822 | /** |
823 | * cap_task_setscheduler - Detemine if scheduler policy change is permitted | |
824 | * @p: The task to affect | |
1d045980 DH |
825 | * |
826 | * Detemine if the requested scheduler policy change is permitted for the | |
827 | * specified task, returning 0 if permission is granted, -ve if denied. | |
828 | */ | |
b0ae1981 | 829 | int cap_task_setscheduler(struct task_struct *p) |
b5376771 SH |
830 | { |
831 | return cap_safe_nice(p); | |
832 | } | |
833 | ||
1d045980 DH |
834 | /** |
835 | * cap_task_ioprio - Detemine if I/O priority change is permitted | |
836 | * @p: The task to affect | |
837 | * @ioprio: The I/O priority to set | |
838 | * | |
839 | * Detemine if the requested I/O priority change is permitted for the specified | |
840 | * task, returning 0 if permission is granted, -ve if denied. | |
841 | */ | |
842 | int cap_task_setioprio(struct task_struct *p, int ioprio) | |
b5376771 SH |
843 | { |
844 | return cap_safe_nice(p); | |
845 | } | |
846 | ||
1d045980 DH |
847 | /** |
848 | * cap_task_ioprio - Detemine if task priority change is permitted | |
849 | * @p: The task to affect | |
850 | * @nice: The nice value to set | |
851 | * | |
852 | * Detemine if the requested task priority change is permitted for the | |
853 | * specified task, returning 0 if permission is granted, -ve if denied. | |
854 | */ | |
855 | int cap_task_setnice(struct task_struct *p, int nice) | |
b5376771 SH |
856 | { |
857 | return cap_safe_nice(p); | |
858 | } | |
859 | ||
3b7391de | 860 | /* |
1d045980 DH |
861 | * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from |
862 | * the current task's bounding set. Returns 0 on success, -ve on error. | |
3b7391de | 863 | */ |
6d6f3328 | 864 | static int cap_prctl_drop(unsigned long cap) |
3b7391de | 865 | { |
6d6f3328 TH |
866 | struct cred *new; |
867 | ||
160da84d | 868 | if (!ns_capable(current_user_ns(), CAP_SETPCAP)) |
3b7391de SH |
869 | return -EPERM; |
870 | if (!cap_valid(cap)) | |
871 | return -EINVAL; | |
d84f4f99 | 872 | |
6d6f3328 TH |
873 | new = prepare_creds(); |
874 | if (!new) | |
875 | return -ENOMEM; | |
d84f4f99 | 876 | cap_lower(new->cap_bset, cap); |
6d6f3328 | 877 | return commit_creds(new); |
3b7391de | 878 | } |
3898b1b4 | 879 | |
1d045980 DH |
880 | /** |
881 | * cap_task_prctl - Implement process control functions for this security module | |
882 | * @option: The process control function requested | |
883 | * @arg2, @arg3, @arg4, @arg5: The argument data for this function | |
884 | * | |
885 | * Allow process control functions (sys_prctl()) to alter capabilities; may | |
886 | * also deny access to other functions not otherwise implemented here. | |
887 | * | |
888 | * Returns 0 or +ve on success, -ENOSYS if this function is not implemented | |
889 | * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM | |
890 | * modules will consider performing the function. | |
891 | */ | |
3898b1b4 | 892 | int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, |
d84f4f99 | 893 | unsigned long arg4, unsigned long arg5) |
3898b1b4 | 894 | { |
6d6f3328 | 895 | const struct cred *old = current_cred(); |
d84f4f99 | 896 | struct cred *new; |
d84f4f99 | 897 | |
3898b1b4 AM |
898 | switch (option) { |
899 | case PR_CAPBSET_READ: | |
900 | if (!cap_valid(arg2)) | |
6d6f3328 TH |
901 | return -EINVAL; |
902 | return !!cap_raised(old->cap_bset, arg2); | |
d84f4f99 | 903 | |
3898b1b4 | 904 | case PR_CAPBSET_DROP: |
6d6f3328 | 905 | return cap_prctl_drop(arg2); |
3898b1b4 AM |
906 | |
907 | /* | |
908 | * The next four prctl's remain to assist with transitioning a | |
909 | * system from legacy UID=0 based privilege (when filesystem | |
910 | * capabilities are not in use) to a system using filesystem | |
911 | * capabilities only - as the POSIX.1e draft intended. | |
912 | * | |
913 | * Note: | |
914 | * | |
915 | * PR_SET_SECUREBITS = | |
916 | * issecure_mask(SECURE_KEEP_CAPS_LOCKED) | |
917 | * | issecure_mask(SECURE_NOROOT) | |
918 | * | issecure_mask(SECURE_NOROOT_LOCKED) | |
919 | * | issecure_mask(SECURE_NO_SETUID_FIXUP) | |
920 | * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) | |
921 | * | |
922 | * will ensure that the current process and all of its | |
923 | * children will be locked into a pure | |
924 | * capability-based-privilege environment. | |
925 | */ | |
926 | case PR_SET_SECUREBITS: | |
6d6f3328 TH |
927 | if ((((old->securebits & SECURE_ALL_LOCKS) >> 1) |
928 | & (old->securebits ^ arg2)) /*[1]*/ | |
929 | || ((old->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/ | |
d84f4f99 | 930 | || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ |
6a9de491 | 931 | || (cap_capable(current_cred(), |
c4a4d603 | 932 | current_cred()->user_ns, CAP_SETPCAP, |
3699c53c | 933 | SECURITY_CAP_AUDIT) != 0) /*[4]*/ |
3898b1b4 AM |
934 | /* |
935 | * [1] no changing of bits that are locked | |
936 | * [2] no unlocking of locks | |
937 | * [3] no setting of unsupported bits | |
938 | * [4] doing anything requires privilege (go read about | |
939 | * the "sendmail capabilities bug") | |
940 | */ | |
d84f4f99 DH |
941 | ) |
942 | /* cannot change a locked bit */ | |
6d6f3328 TH |
943 | return -EPERM; |
944 | ||
945 | new = prepare_creds(); | |
946 | if (!new) | |
947 | return -ENOMEM; | |
d84f4f99 | 948 | new->securebits = arg2; |
6d6f3328 | 949 | return commit_creds(new); |
d84f4f99 | 950 | |
3898b1b4 | 951 | case PR_GET_SECUREBITS: |
6d6f3328 | 952 | return old->securebits; |
3898b1b4 | 953 | |
3898b1b4 | 954 | case PR_GET_KEEPCAPS: |
6d6f3328 | 955 | return !!issecure(SECURE_KEEP_CAPS); |
d84f4f99 | 956 | |
3898b1b4 AM |
957 | case PR_SET_KEEPCAPS: |
958 | if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ | |
6d6f3328 | 959 | return -EINVAL; |
d84f4f99 | 960 | if (issecure(SECURE_KEEP_CAPS_LOCKED)) |
6d6f3328 TH |
961 | return -EPERM; |
962 | ||
963 | new = prepare_creds(); | |
964 | if (!new) | |
965 | return -ENOMEM; | |
d84f4f99 DH |
966 | if (arg2) |
967 | new->securebits |= issecure_mask(SECURE_KEEP_CAPS); | |
3898b1b4 | 968 | else |
d84f4f99 | 969 | new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
6d6f3328 | 970 | return commit_creds(new); |
3898b1b4 | 971 | |
58319057 AL |
972 | case PR_CAP_AMBIENT: |
973 | if (arg2 == PR_CAP_AMBIENT_CLEAR_ALL) { | |
974 | if (arg3 | arg4 | arg5) | |
975 | return -EINVAL; | |
976 | ||
977 | new = prepare_creds(); | |
978 | if (!new) | |
979 | return -ENOMEM; | |
980 | cap_clear(new->cap_ambient); | |
981 | return commit_creds(new); | |
982 | } | |
983 | ||
984 | if (((!cap_valid(arg3)) | arg4 | arg5)) | |
985 | return -EINVAL; | |
986 | ||
987 | if (arg2 == PR_CAP_AMBIENT_IS_SET) { | |
988 | return !!cap_raised(current_cred()->cap_ambient, arg3); | |
989 | } else if (arg2 != PR_CAP_AMBIENT_RAISE && | |
990 | arg2 != PR_CAP_AMBIENT_LOWER) { | |
991 | return -EINVAL; | |
992 | } else { | |
993 | if (arg2 == PR_CAP_AMBIENT_RAISE && | |
994 | (!cap_raised(current_cred()->cap_permitted, arg3) || | |
995 | !cap_raised(current_cred()->cap_inheritable, | |
746bf6d6 AL |
996 | arg3) || |
997 | issecure(SECURE_NO_CAP_AMBIENT_RAISE))) | |
58319057 AL |
998 | return -EPERM; |
999 | ||
1000 | new = prepare_creds(); | |
1001 | if (!new) | |
1002 | return -ENOMEM; | |
1003 | if (arg2 == PR_CAP_AMBIENT_RAISE) | |
1004 | cap_raise(new->cap_ambient, arg3); | |
1005 | else | |
1006 | cap_lower(new->cap_ambient, arg3); | |
1007 | return commit_creds(new); | |
1008 | } | |
1009 | ||
3898b1b4 AM |
1010 | default: |
1011 | /* No functionality available - continue with default */ | |
6d6f3328 | 1012 | return -ENOSYS; |
3898b1b4 | 1013 | } |
1da177e4 LT |
1014 | } |
1015 | ||
1d045980 DH |
1016 | /** |
1017 | * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted | |
1018 | * @mm: The VM space in which the new mapping is to be made | |
1019 | * @pages: The size of the mapping | |
1020 | * | |
1021 | * Determine whether the allocation of a new virtual mapping by the current | |
b1d9e6b0 | 1022 | * task is permitted, returning 1 if permission is granted, 0 if not. |
1d045980 | 1023 | */ |
34b4e4aa | 1024 | int cap_vm_enough_memory(struct mm_struct *mm, long pages) |
1da177e4 LT |
1025 | { |
1026 | int cap_sys_admin = 0; | |
1027 | ||
6a9de491 | 1028 | if (cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN, |
3699c53c | 1029 | SECURITY_CAP_NOAUDIT) == 0) |
1da177e4 | 1030 | cap_sys_admin = 1; |
b1d9e6b0 | 1031 | return cap_sys_admin; |
1da177e4 | 1032 | } |
7c73875e EP |
1033 | |
1034 | /* | |
d007794a | 1035 | * cap_mmap_addr - check if able to map given addr |
7c73875e | 1036 | * @addr: address attempting to be mapped |
7c73875e | 1037 | * |
6f262d8e | 1038 | * If the process is attempting to map memory below dac_mmap_min_addr they need |
7c73875e EP |
1039 | * CAP_SYS_RAWIO. The other parameters to this function are unused by the |
1040 | * capability security module. Returns 0 if this mapping should be allowed | |
1041 | * -EPERM if not. | |
1042 | */ | |
d007794a | 1043 | int cap_mmap_addr(unsigned long addr) |
7c73875e EP |
1044 | { |
1045 | int ret = 0; | |
1046 | ||
a2551df7 | 1047 | if (addr < dac_mmap_min_addr) { |
6a9de491 | 1048 | ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO, |
7c73875e EP |
1049 | SECURITY_CAP_AUDIT); |
1050 | /* set PF_SUPERPRIV if it turns out we allow the low mmap */ | |
1051 | if (ret == 0) | |
1052 | current->flags |= PF_SUPERPRIV; | |
1053 | } | |
1054 | return ret; | |
1055 | } | |
d007794a | 1056 | |
e5467859 AV |
1057 | int cap_mmap_file(struct file *file, unsigned long reqprot, |
1058 | unsigned long prot, unsigned long flags) | |
d007794a | 1059 | { |
e5467859 | 1060 | return 0; |
d007794a | 1061 | } |
b1d9e6b0 CS |
1062 | |
1063 | #ifdef CONFIG_SECURITY | |
1064 | ||
1065 | struct security_hook_list capability_hooks[] = { | |
1066 | LSM_HOOK_INIT(capable, cap_capable), | |
1067 | LSM_HOOK_INIT(settime, cap_settime), | |
1068 | LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check), | |
1069 | LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme), | |
1070 | LSM_HOOK_INIT(capget, cap_capget), | |
1071 | LSM_HOOK_INIT(capset, cap_capset), | |
1072 | LSM_HOOK_INIT(bprm_set_creds, cap_bprm_set_creds), | |
1073 | LSM_HOOK_INIT(bprm_secureexec, cap_bprm_secureexec), | |
1074 | LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv), | |
1075 | LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv), | |
1076 | LSM_HOOK_INIT(mmap_addr, cap_mmap_addr), | |
1077 | LSM_HOOK_INIT(mmap_file, cap_mmap_file), | |
1078 | LSM_HOOK_INIT(task_fix_setuid, cap_task_fix_setuid), | |
1079 | LSM_HOOK_INIT(task_prctl, cap_task_prctl), | |
1080 | LSM_HOOK_INIT(task_setscheduler, cap_task_setscheduler), | |
1081 | LSM_HOOK_INIT(task_setioprio, cap_task_setioprio), | |
1082 | LSM_HOOK_INIT(task_setnice, cap_task_setnice), | |
1083 | LSM_HOOK_INIT(vm_enough_memory, cap_vm_enough_memory), | |
1084 | }; | |
1085 | ||
1086 | void __init capability_add_hooks(void) | |
1087 | { | |
1088 | security_add_hooks(capability_hooks, ARRAY_SIZE(capability_hooks)); | |
1089 | } | |
1090 | ||
1091 | #endif /* CONFIG_SECURITY */ |