blob: 33d34330841344f7329e1b1f313cc531c65aa7a9 [file] [log] [blame]
Andrew Morgane338d262008-02-04 22:29:42 -08001/* Common capabilities, needed by capability.o and root_plug.o
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
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
Randy.Dunlapc59ede72006-01-11 12:17:46 -080010#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/security.h>
15#include <linux/file.h>
16#include <linux/mm.h>
17#include <linux/mman.h>
18#include <linux/pagemap.h>
19#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/skbuff.h>
21#include <linux/netlink.h>
22#include <linux/ptrace.h>
23#include <linux/xattr.h>
24#include <linux/hugetlb.h>
Serge E. Hallynb5376772007-10-16 23:31:36 -070025#include <linux/mount.h>
Serge E. Hallynb460cbc2007-10-18 23:39:52 -070026#include <linux/sched.h>
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -070027#include <linux/prctl.h>
28#include <linux/securebits.h>
Andrew Morgan72c2d582007-10-18 03:05:59 -070029
Linus Torvalds1da177e2005-04-16 15:20:36 -070030int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
31{
32 NETLINK_CB(skb).eff_cap = current->cap_effective;
33 return 0;
34}
35
Darrel Goeddelc7bdb542006-06-27 13:26:11 -070036int cap_netlink_recv(struct sk_buff *skb, int cap)
Linus Torvalds1da177e2005-04-16 15:20:36 -070037{
Darrel Goeddelc7bdb542006-06-27 13:26:11 -070038 if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 return -EPERM;
40 return 0;
41}
42
43EXPORT_SYMBOL(cap_netlink_recv);
44
Andrew G. Morgana6dbb1e2008-01-21 17:18:30 -080045/*
46 * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
47 * function. That is, it has the reverse semantics: cap_capable()
48 * returns 0 when a task has a capability, but the kernel's capable()
49 * returns 1 for this case.
50 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070051int cap_capable (struct task_struct *tsk, int cap)
52{
53 /* Derived from include/linux/sched.h:capable. */
54 if (cap_raised(tsk->cap_effective, cap))
55 return 0;
56 return -EPERM;
57}
58
59int cap_settime(struct timespec *ts, struct timezone *tz)
60{
61 if (!capable(CAP_SYS_TIME))
62 return -EPERM;
63 return 0;
64}
65
66int cap_ptrace (struct task_struct *parent, struct task_struct *child)
67{
68 /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
Chris Wrightd4eb82c2006-03-25 03:07:41 -080069 if (!cap_issubset(child->cap_permitted, parent->cap_permitted) &&
70 !__capable(parent, CAP_SYS_PTRACE))
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 return -EPERM;
72 return 0;
73}
74
75int cap_capget (struct task_struct *target, kernel_cap_t *effective,
76 kernel_cap_t *inheritable, kernel_cap_t *permitted)
77{
78 /* Derived from kernel/capability.c:sys_capget. */
Andrew Morgane338d262008-02-04 22:29:42 -080079 *effective = target->cap_effective;
80 *inheritable = target->cap_inheritable;
81 *permitted = target->cap_permitted;
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 return 0;
83}
84
Andrew Morgan72c2d582007-10-18 03:05:59 -070085#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
86
87static inline int cap_block_setpcap(struct task_struct *target)
88{
89 /*
90 * No support for remote process capability manipulation with
91 * filesystem capability support.
92 */
93 return (target != current);
94}
95
96static inline int cap_inh_is_capped(void)
97{
98 /*
Andrew G. Morgana6dbb1e2008-01-21 17:18:30 -080099 * Return 1 if changes to the inheritable set are limited
100 * to the old permitted set. That is, if the current task
101 * does *not* possess the CAP_SETPCAP capability.
Andrew Morgan72c2d582007-10-18 03:05:59 -0700102 */
Andrew G. Morgana6dbb1e2008-01-21 17:18:30 -0800103 return (cap_capable(current, CAP_SETPCAP) != 0);
Andrew Morgan72c2d582007-10-18 03:05:59 -0700104}
105
Andrew G. Morgan12097262008-07-04 09:59:59 -0700106static inline int cap_limit_ptraced_target(void) { return 1; }
107
Andrew Morgan72c2d582007-10-18 03:05:59 -0700108#else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
109
110static inline int cap_block_setpcap(struct task_struct *t) { return 0; }
111static inline int cap_inh_is_capped(void) { return 1; }
Andrew G. Morgan12097262008-07-04 09:59:59 -0700112static inline int cap_limit_ptraced_target(void)
113{
114 return !capable(CAP_SETPCAP);
115}
Andrew Morgan72c2d582007-10-18 03:05:59 -0700116
117#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
118
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,
120 kernel_cap_t *inheritable, kernel_cap_t *permitted)
121{
Andrew Morgan72c2d582007-10-18 03:05:59 -0700122 if (cap_block_setpcap(target)) {
123 return -EPERM;
124 }
125 if (cap_inh_is_capped()
126 && !cap_issubset(*inheritable,
127 cap_combine(target->cap_inheritable,
128 current->cap_permitted))) {
129 /* incapable of using this inheritable set */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 return -EPERM;
131 }
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800132 if (!cap_issubset(*inheritable,
133 cap_combine(target->cap_inheritable,
134 current->cap_bset))) {
135 /* no new pI capabilities outside bounding set */
136 return -EPERM;
137 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 /* verify restrictions on target's new Permitted set */
140 if (!cap_issubset (*permitted,
141 cap_combine (target->cap_permitted,
142 current->cap_permitted))) {
143 return -EPERM;
144 }
145
146 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
147 if (!cap_issubset (*effective, *permitted)) {
148 return -EPERM;
149 }
150
151 return 0;
152}
153
154void cap_capset_set (struct task_struct *target, kernel_cap_t *effective,
155 kernel_cap_t *inheritable, kernel_cap_t *permitted)
156{
157 target->cap_effective = *effective;
158 target->cap_inheritable = *inheritable;
159 target->cap_permitted = *permitted;
160}
161
Serge E. Hallynb5376772007-10-16 23:31:36 -0700162static inline void bprm_clear_caps(struct linux_binprm *bprm)
163{
164 cap_clear(bprm->cap_inheritable);
165 cap_clear(bprm->cap_permitted);
166 bprm->cap_effective = false;
167}
168
169#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
170
171int cap_inode_need_killpriv(struct dentry *dentry)
172{
173 struct inode *inode = dentry->d_inode;
174 int error;
175
176 if (!inode->i_op || !inode->i_op->getxattr)
177 return 0;
178
179 error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
180 if (error <= 0)
181 return 0;
182 return 1;
183}
184
185int cap_inode_killpriv(struct dentry *dentry)
186{
187 struct inode *inode = dentry->d_inode;
188
189 if (!inode->i_op || !inode->i_op->removexattr)
190 return 0;
191
192 return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
193}
194
Andrew Morgane338d262008-02-04 22:29:42 -0800195static inline int cap_from_disk(struct vfs_cap_data *caps,
196 struct linux_binprm *bprm, unsigned size)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700197{
198 __u32 magic_etc;
Andrew Morgane338d262008-02-04 22:29:42 -0800199 unsigned tocopy, i;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700200
Andrew Morgane338d262008-02-04 22:29:42 -0800201 if (size < sizeof(magic_etc))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700202 return -EINVAL;
203
Andrew Morgane338d262008-02-04 22:29:42 -0800204 magic_etc = le32_to_cpu(caps->magic_etc);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700205
206 switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
Andrew Morgane338d262008-02-04 22:29:42 -0800207 case VFS_CAP_REVISION_1:
208 if (size != XATTR_CAPS_SZ_1)
209 return -EINVAL;
210 tocopy = VFS_CAP_U32_1;
211 break;
212 case VFS_CAP_REVISION_2:
213 if (size != XATTR_CAPS_SZ_2)
214 return -EINVAL;
215 tocopy = VFS_CAP_U32_2;
216 break;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700217 default:
218 return -EINVAL;
219 }
Andrew Morgane338d262008-02-04 22:29:42 -0800220
221 if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
222 bprm->cap_effective = true;
223 } else {
224 bprm->cap_effective = false;
225 }
226
227 for (i = 0; i < tocopy; ++i) {
228 bprm->cap_permitted.cap[i] =
229 le32_to_cpu(caps->data[i].permitted);
230 bprm->cap_inheritable.cap[i] =
231 le32_to_cpu(caps->data[i].inheritable);
232 }
233 while (i < VFS_CAP_U32) {
234 bprm->cap_permitted.cap[i] = 0;
235 bprm->cap_inheritable.cap[i] = 0;
236 i++;
237 }
238
239 return 0;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700240}
241
242/* Locate any VFS capabilities: */
243static int get_file_caps(struct linux_binprm *bprm)
244{
245 struct dentry *dentry;
246 int rc = 0;
Andrew Morgane338d262008-02-04 22:29:42 -0800247 struct vfs_cap_data vcaps;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700248 struct inode *inode;
249
250 if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
251 bprm_clear_caps(bprm);
252 return 0;
253 }
254
255 dentry = dget(bprm->file->f_dentry);
256 inode = dentry->d_inode;
257 if (!inode->i_op || !inode->i_op->getxattr)
258 goto out;
259
Andrew Morgane338d262008-02-04 22:29:42 -0800260 rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &vcaps,
261 XATTR_CAPS_SZ);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700262 if (rc == -ENODATA || rc == -EOPNOTSUPP) {
263 /* no data, that's ok */
264 rc = 0;
265 goto out;
266 }
267 if (rc < 0)
268 goto out;
269
Andrew Morgane338d262008-02-04 22:29:42 -0800270 rc = cap_from_disk(&vcaps, bprm, rc);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700271 if (rc)
272 printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
Harvey Harrisondd6f9532008-03-06 10:03:59 +1100273 __func__, rc, bprm->filename);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700274
275out:
276 dput(dentry);
277 if (rc)
278 bprm_clear_caps(bprm);
279
280 return rc;
281}
282
283#else
284int cap_inode_need_killpriv(struct dentry *dentry)
285{
286 return 0;
287}
288
289int cap_inode_killpriv(struct dentry *dentry)
290{
291 return 0;
292}
293
294static inline int get_file_caps(struct linux_binprm *bprm)
295{
296 bprm_clear_caps(bprm);
297 return 0;
298}
299#endif
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301int cap_bprm_set_security (struct linux_binprm *bprm)
302{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700303 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Serge E. Hallynb5376772007-10-16 23:31:36 -0700305 ret = get_file_caps(bprm);
306 if (ret)
307 printk(KERN_NOTICE "%s: get_file_caps returned %d for %s\n",
Harvey Harrisondd6f9532008-03-06 10:03:59 +1100308 __func__, ret, bprm->filename);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
310 /* To support inheritance of root-permissions and suid-root
311 * executables under compatibility mode, we raise all three
312 * capability sets for the file.
313 *
314 * If only the real uid is 0, we only raise the inheritable
315 * and permitted sets of the executable file.
316 */
317
318 if (!issecure (SECURE_NOROOT)) {
319 if (bprm->e_uid == 0 || current->uid == 0) {
320 cap_set_full (bprm->cap_inheritable);
321 cap_set_full (bprm->cap_permitted);
322 }
323 if (bprm->e_uid == 0)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700324 bprm->cap_effective = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 }
Serge E. Hallynb5376772007-10-16 23:31:36 -0700326
327 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328}
329
330void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
331{
332 /* Derived from fs/exec.c:compute_creds. */
333 kernel_cap_t new_permitted, working;
334
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800335 new_permitted = cap_intersect(bprm->cap_permitted,
336 current->cap_bset);
337 working = cap_intersect(bprm->cap_inheritable,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 current->cap_inheritable);
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800339 new_permitted = cap_combine(new_permitted, working);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341 if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
342 !cap_issubset (new_permitted, current->cap_permitted)) {
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700343 set_dumpable(current->mm, suid_dumpable);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700344 current->pdeath_signal = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345
346 if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
347 if (!capable(CAP_SETUID)) {
348 bprm->e_uid = current->uid;
349 bprm->e_gid = current->gid;
350 }
Andrew G. Morgan12097262008-07-04 09:59:59 -0700351 if (cap_limit_ptraced_target()) {
352 new_permitted =
353 cap_intersect(new_permitted,
354 current->cap_permitted);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 }
356 }
357 }
358
359 current->suid = current->euid = current->fsuid = bprm->e_uid;
360 current->sgid = current->egid = current->fsgid = bprm->e_gid;
361
362 /* For init, we want to retain the capabilities set
363 * in the init_task struct. Thus we skip the usual
364 * capability rules */
Serge E. Hallynb460cbc2007-10-18 23:39:52 -0700365 if (!is_global_init(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 current->cap_permitted = new_permitted;
Andrew Morgane338d262008-02-04 22:29:42 -0800367 if (bprm->cap_effective)
368 current->cap_effective = new_permitted;
369 else
370 cap_clear(current->cap_effective);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 }
372
373 /* AUD: Audit candidate if current->cap_effective is set */
374
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700375 current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376}
377
378int cap_bprm_secureexec (struct linux_binprm *bprm)
379{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700380 if (current->uid != 0) {
381 if (bprm->cap_effective)
382 return 1;
383 if (!cap_isclear(bprm->cap_permitted))
384 return 1;
385 if (!cap_isclear(bprm->cap_inheritable))
386 return 1;
387 }
388
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 return (current->euid != current->uid ||
390 current->egid != current->gid);
391}
392
David Howells8f0cfa52008-04-29 00:59:41 -0700393int cap_inode_setxattr(struct dentry *dentry, const char *name,
394 const void *value, size_t size, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700396 if (!strcmp(name, XATTR_NAME_CAPS)) {
397 if (!capable(CAP_SETFCAP))
398 return -EPERM;
399 return 0;
400 } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
402 !capable(CAP_SYS_ADMIN))
403 return -EPERM;
404 return 0;
405}
406
David Howells8f0cfa52008-04-29 00:59:41 -0700407int cap_inode_removexattr(struct dentry *dentry, const char *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700409 if (!strcmp(name, XATTR_NAME_CAPS)) {
410 if (!capable(CAP_SETFCAP))
411 return -EPERM;
412 return 0;
413 } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
415 !capable(CAP_SYS_ADMIN))
416 return -EPERM;
417 return 0;
418}
419
420/* moved from kernel/sys.c. */
421/*
422 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
423 * a process after a call to setuid, setreuid, or setresuid.
424 *
425 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
426 * {r,e,s}uid != 0, the permitted and effective capabilities are
427 * cleared.
428 *
429 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
430 * capabilities of the process are cleared.
431 *
432 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
433 * capabilities are set to the permitted capabilities.
434 *
435 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
436 * never happen.
437 *
438 * -astor
439 *
440 * cevans - New behaviour, Oct '99
441 * A process may, via prctl(), elect to keep its capabilities when it
442 * calls setuid() and switches away from uid==0. Both permitted and
443 * effective sets will be retained.
444 * Without this change, it was impossible for a daemon to drop only some
445 * of its privilege. The call to setuid(!=0) would drop all privileges!
446 * Keeping uid 0 is not an option because uid 0 owns too many vital
447 * files..
448 * Thanks to Olaf Kirch and Peter Benie for spotting this.
449 */
450static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
451 int old_suid)
452{
453 if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
454 (current->uid != 0 && current->euid != 0 && current->suid != 0) &&
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700455 !issecure(SECURE_KEEP_CAPS)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 cap_clear (current->cap_permitted);
457 cap_clear (current->cap_effective);
458 }
459 if (old_euid == 0 && current->euid != 0) {
460 cap_clear (current->cap_effective);
461 }
462 if (old_euid != 0 && current->euid == 0) {
463 current->cap_effective = current->cap_permitted;
464 }
465}
466
467int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
468 int flags)
469{
470 switch (flags) {
471 case LSM_SETID_RE:
472 case LSM_SETID_ID:
473 case LSM_SETID_RES:
474 /* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
475 if (!issecure (SECURE_NO_SETUID_FIXUP)) {
476 cap_emulate_setxuid (old_ruid, old_euid, old_suid);
477 }
478 break;
479 case LSM_SETID_FS:
480 {
481 uid_t old_fsuid = old_ruid;
482
483 /* Copied from kernel/sys.c:setfsuid. */
484
485 /*
486 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
487 * if not, we might be a bit too harsh here.
488 */
489
490 if (!issecure (SECURE_NO_SETUID_FIXUP)) {
491 if (old_fsuid == 0 && current->fsuid != 0) {
Andrew Morgane338d262008-02-04 22:29:42 -0800492 current->cap_effective =
493 cap_drop_fs_set(
494 current->cap_effective);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 }
496 if (old_fsuid != 0 && current->fsuid == 0) {
Andrew Morgane338d262008-02-04 22:29:42 -0800497 current->cap_effective =
498 cap_raise_fs_set(
499 current->cap_effective,
500 current->cap_permitted);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 }
502 }
503 break;
504 }
505 default:
506 return -EINVAL;
507 }
508
509 return 0;
510}
511
Serge E. Hallynb5376772007-10-16 23:31:36 -0700512#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
513/*
514 * Rationale: code calling task_setscheduler, task_setioprio, and
515 * task_setnice, assumes that
516 * . if capable(cap_sys_nice), then those actions should be allowed
517 * . if not capable(cap_sys_nice), but acting on your own processes,
518 * then those actions should be allowed
519 * This is insufficient now since you can call code without suid, but
520 * yet with increased caps.
521 * So we check for increased caps on the target process.
522 */
523static inline int cap_safe_nice(struct task_struct *p)
524{
525 if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
526 !__capable(current, CAP_SYS_NICE))
527 return -EPERM;
528 return 0;
529}
530
531int cap_task_setscheduler (struct task_struct *p, int policy,
532 struct sched_param *lp)
533{
534 return cap_safe_nice(p);
535}
536
537int cap_task_setioprio (struct task_struct *p, int ioprio)
538{
539 return cap_safe_nice(p);
540}
541
542int cap_task_setnice (struct task_struct *p, int nice)
543{
544 return cap_safe_nice(p);
545}
546
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800547/*
548 * called from kernel/sys.c for prctl(PR_CABSET_DROP)
549 * done without task_capability_lock() because it introduces
550 * no new races - i.e. only another task doing capget() on
551 * this task could get inconsistent info. There can be no
552 * racing writer bc a task can only change its own caps.
553 */
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700554static long cap_prctl_drop(unsigned long cap)
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800555{
556 if (!capable(CAP_SETPCAP))
557 return -EPERM;
558 if (!cap_valid(cap))
559 return -EINVAL;
560 cap_lower(current->cap_bset, cap);
561 return 0;
562}
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700563
Serge E. Hallynb5376772007-10-16 23:31:36 -0700564#else
565int cap_task_setscheduler (struct task_struct *p, int policy,
566 struct sched_param *lp)
567{
568 return 0;
569}
570int cap_task_setioprio (struct task_struct *p, int ioprio)
571{
572 return 0;
573}
574int cap_task_setnice (struct task_struct *p, int nice)
575{
576 return 0;
577}
Serge E. Hallynb5376772007-10-16 23:31:36 -0700578#endif
579
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700580int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
581 unsigned long arg4, unsigned long arg5, long *rc_p)
582{
583 long error = 0;
584
585 switch (option) {
586 case PR_CAPBSET_READ:
587 if (!cap_valid(arg2))
588 error = -EINVAL;
589 else
590 error = !!cap_raised(current->cap_bset, arg2);
591 break;
592#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
593 case PR_CAPBSET_DROP:
594 error = cap_prctl_drop(arg2);
595 break;
596
597 /*
598 * The next four prctl's remain to assist with transitioning a
599 * system from legacy UID=0 based privilege (when filesystem
600 * capabilities are not in use) to a system using filesystem
601 * capabilities only - as the POSIX.1e draft intended.
602 *
603 * Note:
604 *
605 * PR_SET_SECUREBITS =
606 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
607 * | issecure_mask(SECURE_NOROOT)
608 * | issecure_mask(SECURE_NOROOT_LOCKED)
609 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
610 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
611 *
612 * will ensure that the current process and all of its
613 * children will be locked into a pure
614 * capability-based-privilege environment.
615 */
616 case PR_SET_SECUREBITS:
617 if ((((current->securebits & SECURE_ALL_LOCKS) >> 1)
618 & (current->securebits ^ arg2)) /*[1]*/
619 || ((current->securebits & SECURE_ALL_LOCKS
620 & ~arg2)) /*[2]*/
621 || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
622 || (cap_capable(current, CAP_SETPCAP) != 0)) { /*[4]*/
623 /*
624 * [1] no changing of bits that are locked
625 * [2] no unlocking of locks
626 * [3] no setting of unsupported bits
627 * [4] doing anything requires privilege (go read about
628 * the "sendmail capabilities bug")
629 */
630 error = -EPERM; /* cannot change a locked bit */
631 } else {
632 current->securebits = arg2;
633 }
634 break;
635 case PR_GET_SECUREBITS:
636 error = current->securebits;
637 break;
638
639#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
640
641 case PR_GET_KEEPCAPS:
642 if (issecure(SECURE_KEEP_CAPS))
643 error = 1;
644 break;
645 case PR_SET_KEEPCAPS:
646 if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
647 error = -EINVAL;
648 else if (issecure(SECURE_KEEP_CAPS_LOCKED))
649 error = -EPERM;
650 else if (arg2)
651 current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
652 else
653 current->securebits &=
654 ~issecure_mask(SECURE_KEEP_CAPS);
655 break;
656
657 default:
658 /* No functionality available - continue with default */
659 return 0;
660 }
661
662 /* Functionality provided */
663 *rc_p = error;
664 return 1;
665}
666
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667void cap_task_reparent_to_init (struct task_struct *p)
668{
Andrew Morgane338d262008-02-04 22:29:42 -0800669 cap_set_init_eff(p->cap_effective);
670 cap_clear(p->cap_inheritable);
671 cap_set_full(p->cap_permitted);
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700672 p->securebits = SECUREBITS_DEFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 return;
674}
675
676int cap_syslog (int type)
677{
678 if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
679 return -EPERM;
680 return 0;
681}
682
Alan Cox34b4e4a2007-08-22 14:01:28 -0700683int cap_vm_enough_memory(struct mm_struct *mm, long pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684{
685 int cap_sys_admin = 0;
686
687 if (cap_capable(current, CAP_SYS_ADMIN) == 0)
688 cap_sys_admin = 1;
Alan Cox34b4e4a2007-08-22 14:01:28 -0700689 return __vm_enough_memory(mm, pages, cap_sys_admin);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690}
691