1 /* Common capabilities, needed by capability.o.
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.
10 #include <linux/capability.h>
11 #include <linux/audit.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/security.h>
16 #include <linux/file.h>
18 #include <linux/mman.h>
19 #include <linux/pagemap.h>
20 #include <linux/swap.h>
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>
26 #include <linux/mount.h>
27 #include <linux/sched.h>
28 #include <linux/prctl.h>
29 #include <linux/securebits.h>
30 #include <linux/user_namespace.h>
31 #include <linux/binfmts.h>
32 #include <linux/personality.h>
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.
43 * Warn if that happens, once per boot.
45 static void warn_setuid_and_fcaps_mixed(const char *fname
)
49 printk(KERN_INFO
"warning: `%s' has both setuid-root and"
50 " effective capabilities. Therefore not raising all"
51 " capabilities.\n", fname
);
56 int cap_netlink_send(struct sock
*sk
, struct sk_buff
*skb
)
62 * cap_capable - Determine whether a task has a particular effective capability
63 * @cred: The credentials to use
64 * @ns: The user namespace in which we need the capability
65 * @cap: The capability to check for
66 * @audit: Whether to write an audit message or not
68 * Determine whether the nominated task has the specified capability amongst
69 * its effective set, returning 0 if it does, -ve if it does not.
71 * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable()
72 * and has_capability() functions. That is, it has the reverse semantics:
73 * cap_has_capability() returns 0 when a task has a capability, but the
74 * kernel's capable() and has_capability() returns 1 for this case.
76 int cap_capable(const struct cred
*cred
, struct user_namespace
*targ_ns
,
79 struct user_namespace
*ns
= targ_ns
;
81 /* See if cred has the capability in the target user namespace
82 * by examining the target user namespace and all of the target
83 * user namespace's parents.
86 /* Do we have the necessary capabilities? */
87 if (ns
== cred
->user_ns
)
88 return cap_raised(cred
->cap_effective
, cap
) ? 0 : -EPERM
;
90 /* Have we tried all of the parent namespaces? */
91 if (ns
== &init_user_ns
)
95 * The owner of the user namespace in the parent of the
96 * user namespace has all caps.
98 if ((ns
->parent
== cred
->user_ns
) && uid_eq(ns
->owner
, cred
->euid
))
102 * If you have a capability in a parent user ns, then you have
103 * it over all children user namespaces as well.
108 /* We never get here */
112 * cap_settime - Determine whether the current process may set the system clock
113 * @ts: The time to set
114 * @tz: The timezone to set
116 * Determine whether the current process may set the system clock and timezone
117 * information, returning 0 if permission granted, -ve if denied.
119 int cap_settime(const struct timespec
*ts
, const struct timezone
*tz
)
121 if (!capable(CAP_SYS_TIME
))
127 * cap_ptrace_access_check - Determine whether the current process may access
129 * @child: The process to be accessed
130 * @mode: The mode of attachment.
132 * If we are in the same or an ancestor user_ns and have all the target
133 * task's capabilities, then ptrace access is allowed.
134 * If we have the ptrace capability to the target user_ns, then ptrace
138 * Determine whether a process may access another, returning 0 if permission
139 * granted, -ve if denied.
141 int cap_ptrace_access_check(struct task_struct
*child
, unsigned int mode
)
144 const struct cred
*cred
, *child_cred
;
147 cred
= current_cred();
148 child_cred
= __task_cred(child
);
149 if (cred
->user_ns
== child_cred
->user_ns
&&
150 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
152 if (ns_capable(child_cred
->user_ns
, CAP_SYS_PTRACE
))
161 * cap_ptrace_traceme - Determine whether another process may trace the current
162 * @parent: The task proposed to be the tracer
164 * If parent is in the same or an ancestor user_ns and has all current's
165 * capabilities, then ptrace access is allowed.
166 * If parent has the ptrace capability to current's user_ns, then ptrace
170 * Determine whether the nominated task is permitted to trace the current
171 * process, returning 0 if permission is granted, -ve if denied.
173 int cap_ptrace_traceme(struct task_struct
*parent
)
176 const struct cred
*cred
, *child_cred
;
179 cred
= __task_cred(parent
);
180 child_cred
= current_cred();
181 if (cred
->user_ns
== child_cred
->user_ns
&&
182 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
184 if (has_ns_capability(parent
, child_cred
->user_ns
, CAP_SYS_PTRACE
))
193 * cap_capget - Retrieve a task's capability sets
194 * @target: The task from which to retrieve the capability sets
195 * @effective: The place to record the effective set
196 * @inheritable: The place to record the inheritable set
197 * @permitted: The place to record the permitted set
199 * This function retrieves the capabilities of the nominated task and returns
200 * them to the caller.
202 int cap_capget(struct task_struct
*target
, kernel_cap_t
*effective
,
203 kernel_cap_t
*inheritable
, kernel_cap_t
*permitted
)
205 const struct cred
*cred
;
207 /* Derived from kernel/capability.c:sys_capget. */
209 cred
= __task_cred(target
);
210 *effective
= cred
->cap_effective
;
211 *inheritable
= cred
->cap_inheritable
;
212 *permitted
= cred
->cap_permitted
;
218 * Determine whether the inheritable capabilities are limited to the old
219 * permitted set. Returns 1 if they are limited, 0 if they are not.
221 static inline int cap_inh_is_capped(void)
224 /* they are so limited unless the current task has the CAP_SETPCAP
227 if (cap_capable(current_cred(), current_cred()->user_ns
,
228 CAP_SETPCAP
, SECURITY_CAP_AUDIT
) == 0)
234 * cap_capset - Validate and apply proposed changes to current's capabilities
235 * @new: The proposed new credentials; alterations should be made here
236 * @old: The current task's current credentials
237 * @effective: A pointer to the proposed new effective capabilities set
238 * @inheritable: A pointer to the proposed new inheritable capabilities set
239 * @permitted: A pointer to the proposed new permitted capabilities set
241 * This function validates and applies a proposed mass change to the current
242 * process's capability sets. The changes are made to the proposed new
243 * credentials, and assuming no error, will be committed by the caller of LSM.
245 int cap_capset(struct cred
*new,
246 const struct cred
*old
,
247 const kernel_cap_t
*effective
,
248 const kernel_cap_t
*inheritable
,
249 const kernel_cap_t
*permitted
)
251 if (cap_inh_is_capped() &&
252 !cap_issubset(*inheritable
,
253 cap_combine(old
->cap_inheritable
,
254 old
->cap_permitted
)))
255 /* incapable of using this inheritable set */
258 if (!cap_issubset(*inheritable
,
259 cap_combine(old
->cap_inheritable
,
261 /* no new pI capabilities outside bounding set */
264 /* verify restrictions on target's new Permitted set */
265 if (!cap_issubset(*permitted
, old
->cap_permitted
))
268 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
269 if (!cap_issubset(*effective
, *permitted
))
272 new->cap_effective
= *effective
;
273 new->cap_inheritable
= *inheritable
;
274 new->cap_permitted
= *permitted
;
279 * Clear proposed capability sets for execve().
281 static inline void bprm_clear_caps(struct linux_binprm
*bprm
)
283 cap_clear(bprm
->cred
->cap_permitted
);
284 bprm
->cap_effective
= false;
288 * cap_inode_need_killpriv - Determine if inode change affects privileges
289 * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
291 * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
292 * affects the security markings on that inode, and if it is, should
293 * inode_killpriv() be invoked or the change rejected?
295 * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
296 * -ve to deny the change.
298 int cap_inode_need_killpriv(struct dentry
*dentry
)
300 struct inode
*inode
= dentry
->d_inode
;
303 if (!inode
->i_op
->getxattr
)
306 error
= inode
->i_op
->getxattr(dentry
, XATTR_NAME_CAPS
, NULL
, 0);
313 * cap_inode_killpriv - Erase the security markings on an inode
314 * @dentry: The inode/dentry to alter
316 * Erase the privilege-enhancing security markings on an inode.
318 * Returns 0 if successful, -ve on error.
320 int cap_inode_killpriv(struct dentry
*dentry
)
322 struct inode
*inode
= dentry
->d_inode
;
324 if (!inode
->i_op
->removexattr
)
327 return inode
->i_op
->removexattr(dentry
, XATTR_NAME_CAPS
);
331 * Calculate the new process capability sets from the capability sets attached
334 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data
*caps
,
335 struct linux_binprm
*bprm
,
339 struct cred
*new = bprm
->cred
;
343 if (caps
->magic_etc
& VFS_CAP_FLAGS_EFFECTIVE
)
346 if (caps
->magic_etc
& VFS_CAP_REVISION_MASK
)
349 CAP_FOR_EACH_U32(i
) {
350 __u32 permitted
= caps
->permitted
.cap
[i
];
351 __u32 inheritable
= caps
->inheritable
.cap
[i
];
354 * pP' = (X & fP) | (pI & fI)
356 new->cap_permitted
.cap
[i
] =
357 (new->cap_bset
.cap
[i
] & permitted
) |
358 (new->cap_inheritable
.cap
[i
] & inheritable
);
360 if (permitted
& ~new->cap_permitted
.cap
[i
])
361 /* insufficient to execute correctly */
366 * For legacy apps, with no internal support for recognizing they
367 * do not have enough capabilities, we return an error if they are
368 * missing some "forced" (aka file-permitted) capabilities.
370 return *effective
? ret
: 0;
374 * Extract the on-exec-apply capability sets for an executable file.
376 int get_vfs_caps_from_disk(const struct dentry
*dentry
, struct cpu_vfs_cap_data
*cpu_caps
)
378 struct inode
*inode
= dentry
->d_inode
;
382 struct vfs_cap_data caps
;
384 memset(cpu_caps
, 0, sizeof(struct cpu_vfs_cap_data
));
386 if (!inode
|| !inode
->i_op
->getxattr
)
389 size
= inode
->i_op
->getxattr((struct dentry
*)dentry
, XATTR_NAME_CAPS
, &caps
,
391 if (size
== -ENODATA
|| size
== -EOPNOTSUPP
)
392 /* no data, that's ok */
397 if (size
< sizeof(magic_etc
))
400 cpu_caps
->magic_etc
= magic_etc
= le32_to_cpu(caps
.magic_etc
);
402 switch (magic_etc
& VFS_CAP_REVISION_MASK
) {
403 case VFS_CAP_REVISION_1
:
404 if (size
!= XATTR_CAPS_SZ_1
)
406 tocopy
= VFS_CAP_U32_1
;
408 case VFS_CAP_REVISION_2
:
409 if (size
!= XATTR_CAPS_SZ_2
)
411 tocopy
= VFS_CAP_U32_2
;
417 CAP_FOR_EACH_U32(i
) {
420 cpu_caps
->permitted
.cap
[i
] = le32_to_cpu(caps
.data
[i
].permitted
);
421 cpu_caps
->inheritable
.cap
[i
] = le32_to_cpu(caps
.data
[i
].inheritable
);
428 * Attempt to get the on-exec apply capability sets for an executable file from
429 * its xattrs and, if present, apply them to the proposed credentials being
430 * constructed by execve().
432 static int get_file_caps(struct linux_binprm
*bprm
, bool *effective
, bool *has_cap
)
434 struct dentry
*dentry
;
436 struct cpu_vfs_cap_data vcaps
;
438 bprm_clear_caps(bprm
);
440 if (!file_caps_enabled
)
443 if (bprm
->file
->f_path
.mnt
->mnt_flags
& MNT_NOSUID
)
446 dentry
= dget(bprm
->file
->f_dentry
);
448 rc
= get_vfs_caps_from_disk(dentry
, &vcaps
);
451 printk(KERN_NOTICE
"%s: get_vfs_caps_from_disk returned %d for %s\n",
452 __func__
, rc
, bprm
->filename
);
453 else if (rc
== -ENODATA
)
458 rc
= bprm_caps_from_vfs_caps(&vcaps
, bprm
, effective
, has_cap
);
460 printk(KERN_NOTICE
"%s: cap_from_disk returned %d for %s\n",
461 __func__
, rc
, bprm
->filename
);
466 bprm_clear_caps(bprm
);
472 * cap_bprm_set_creds - Set up the proposed credentials for execve().
473 * @bprm: The execution parameters, including the proposed creds
475 * Set up the proposed credentials for a new execution context being
476 * constructed by execve(). The proposed creds in @bprm->cred is altered,
477 * which won't take effect immediately. Returns 0 if successful, -ve on error.
479 int cap_bprm_set_creds(struct linux_binprm
*bprm
)
481 const struct cred
*old
= current_cred();
482 struct cred
*new = bprm
->cred
;
483 bool effective
, has_cap
= false;
488 ret
= get_file_caps(bprm
, &effective
, &has_cap
);
492 root_uid
= make_kuid(new->user_ns
, 0);
494 if (!issecure(SECURE_NOROOT
)) {
496 * If the legacy file capability is set, then don't set privs
497 * for a setuid root binary run by a non-root user. Do set it
498 * for a root user just to cause least surprise to an admin.
500 if (has_cap
&& !uid_eq(new->uid
, root_uid
) && uid_eq(new->euid
, root_uid
)) {
501 warn_setuid_and_fcaps_mixed(bprm
->filename
);
505 * To support inheritance of root-permissions and suid-root
506 * executables under compatibility mode, we override the
507 * capability sets for the file.
509 * If only the real uid is 0, we do not set the effective bit.
511 if (uid_eq(new->euid
, root_uid
) || uid_eq(new->uid
, root_uid
)) {
512 /* pP' = (cap_bset & ~0) | (pI & ~0) */
513 new->cap_permitted
= cap_combine(old
->cap_bset
,
514 old
->cap_inheritable
);
516 if (uid_eq(new->euid
, root_uid
))
521 /* if we have fs caps, clear dangerous personality flags */
522 if (!cap_issubset(new->cap_permitted
, old
->cap_permitted
))
523 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
526 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
527 * credentials unless they have the appropriate permit.
529 * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
531 if ((!uid_eq(new->euid
, old
->uid
) ||
532 !gid_eq(new->egid
, old
->gid
) ||
533 !cap_issubset(new->cap_permitted
, old
->cap_permitted
)) &&
534 bprm
->unsafe
& ~LSM_UNSAFE_PTRACE_CAP
) {
535 /* downgrade; they get no more than they had, and maybe less */
536 if (!capable(CAP_SETUID
) ||
537 (bprm
->unsafe
& LSM_UNSAFE_NO_NEW_PRIVS
)) {
538 new->euid
= new->uid
;
539 new->egid
= new->gid
;
541 new->cap_permitted
= cap_intersect(new->cap_permitted
,
545 new->suid
= new->fsuid
= new->euid
;
546 new->sgid
= new->fsgid
= new->egid
;
549 new->cap_effective
= new->cap_permitted
;
551 cap_clear(new->cap_effective
);
552 bprm
->cap_effective
= effective
;
555 * Audit candidate if current->cap_effective is set
557 * We do not bother to audit if 3 things are true:
558 * 1) cap_effective has all caps
560 * 3) root is supposed to have all caps (SECURE_NOROOT)
561 * Since this is just a normal root execing a process.
563 * Number 1 above might fail if you don't have a full bset, but I think
564 * that is interesting information to audit.
566 if (!cap_isclear(new->cap_effective
)) {
567 if (!cap_issubset(CAP_FULL_SET
, new->cap_effective
) ||
568 !uid_eq(new->euid
, root_uid
) || !uid_eq(new->uid
, root_uid
) ||
569 issecure(SECURE_NOROOT
)) {
570 ret
= audit_log_bprm_fcaps(bprm
, new, old
);
576 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
581 * cap_bprm_secureexec - Determine whether a secure execution is required
582 * @bprm: The execution parameters
584 * Determine whether a secure execution is required, return 1 if it is, and 0
587 * The credentials have been committed by this point, and so are no longer
588 * available through @bprm->cred.
590 int cap_bprm_secureexec(struct linux_binprm
*bprm
)
592 const struct cred
*cred
= current_cred();
593 kuid_t root_uid
= make_kuid(cred
->user_ns
, 0);
595 if (!uid_eq(cred
->uid
, root_uid
)) {
596 if (bprm
->cap_effective
)
598 if (!cap_isclear(cred
->cap_permitted
))
602 return (!uid_eq(cred
->euid
, cred
->uid
) ||
603 !gid_eq(cred
->egid
, cred
->gid
));
607 * cap_inode_setxattr - Determine whether an xattr may be altered
608 * @dentry: The inode/dentry being altered
609 * @name: The name of the xattr to be changed
610 * @value: The value that the xattr will be changed to
611 * @size: The size of value
612 * @flags: The replacement flag
614 * Determine whether an xattr may be altered or set on an inode, returning 0 if
615 * permission is granted, -ve if denied.
617 * This is used to make sure security xattrs don't get updated or set by those
618 * who aren't privileged to do so.
620 int cap_inode_setxattr(struct dentry
*dentry
, const char *name
,
621 const void *value
, size_t size
, int flags
)
623 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
624 if (!capable(CAP_SETFCAP
))
629 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
630 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
631 !capable(CAP_SYS_ADMIN
))
637 * cap_inode_removexattr - Determine whether an xattr may be removed
638 * @dentry: The inode/dentry being altered
639 * @name: The name of the xattr to be changed
641 * Determine whether an xattr may be removed from an inode, returning 0 if
642 * permission is granted, -ve if denied.
644 * This is used to make sure security xattrs don't get removed by those who
645 * aren't privileged to remove them.
647 int cap_inode_removexattr(struct dentry
*dentry
, const char *name
)
649 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
650 if (!capable(CAP_SETFCAP
))
655 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
656 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
657 !capable(CAP_SYS_ADMIN
))
663 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
664 * a process after a call to setuid, setreuid, or setresuid.
666 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
667 * {r,e,s}uid != 0, the permitted and effective capabilities are
670 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
671 * capabilities of the process are cleared.
673 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
674 * capabilities are set to the permitted capabilities.
676 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
681 * cevans - New behaviour, Oct '99
682 * A process may, via prctl(), elect to keep its capabilities when it
683 * calls setuid() and switches away from uid==0. Both permitted and
684 * effective sets will be retained.
685 * Without this change, it was impossible for a daemon to drop only some
686 * of its privilege. The call to setuid(!=0) would drop all privileges!
687 * Keeping uid 0 is not an option because uid 0 owns too many vital
689 * Thanks to Olaf Kirch and Peter Benie for spotting this.
691 static inline void cap_emulate_setxuid(struct cred
*new, const struct cred
*old
)
693 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
695 if ((uid_eq(old
->uid
, root_uid
) ||
696 uid_eq(old
->euid
, root_uid
) ||
697 uid_eq(old
->suid
, root_uid
)) &&
698 (!uid_eq(new->uid
, root_uid
) &&
699 !uid_eq(new->euid
, root_uid
) &&
700 !uid_eq(new->suid
, root_uid
)) &&
701 !issecure(SECURE_KEEP_CAPS
)) {
702 cap_clear(new->cap_permitted
);
703 cap_clear(new->cap_effective
);
705 if (uid_eq(old
->euid
, root_uid
) && !uid_eq(new->euid
, root_uid
))
706 cap_clear(new->cap_effective
);
707 if (!uid_eq(old
->euid
, root_uid
) && uid_eq(new->euid
, root_uid
))
708 new->cap_effective
= new->cap_permitted
;
712 * cap_task_fix_setuid - Fix up the results of setuid() call
713 * @new: The proposed credentials
714 * @old: The current task's current credentials
715 * @flags: Indications of what has changed
717 * Fix up the results of setuid() call before the credential changes are
718 * actually applied, returning 0 to grant the changes, -ve to deny them.
720 int cap_task_fix_setuid(struct cred
*new, const struct cred
*old
, int flags
)
726 /* juggle the capabilities to follow [RES]UID changes unless
727 * otherwise suppressed */
728 if (!issecure(SECURE_NO_SETUID_FIXUP
))
729 cap_emulate_setxuid(new, old
);
733 /* juggle the capabilties to follow FSUID changes, unless
734 * otherwise suppressed
736 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
737 * if not, we might be a bit too harsh here.
739 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
740 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
741 if (uid_eq(old
->fsuid
, root_uid
) && !uid_eq(new->fsuid
, root_uid
))
743 cap_drop_fs_set(new->cap_effective
);
745 if (!uid_eq(old
->fsuid
, root_uid
) && uid_eq(new->fsuid
, root_uid
))
747 cap_raise_fs_set(new->cap_effective
,
760 * Rationale: code calling task_setscheduler, task_setioprio, and
761 * task_setnice, assumes that
762 * . if capable(cap_sys_nice), then those actions should be allowed
763 * . if not capable(cap_sys_nice), but acting on your own processes,
764 * then those actions should be allowed
765 * This is insufficient now since you can call code without suid, but
766 * yet with increased caps.
767 * So we check for increased caps on the target process.
769 static int cap_safe_nice(struct task_struct
*p
)
771 int is_subset
, ret
= 0;
774 is_subset
= cap_issubset(__task_cred(p
)->cap_permitted
,
775 current_cred()->cap_permitted
);
776 if (!is_subset
&& !ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
))
784 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
785 * @p: The task to affect
787 * Detemine if the requested scheduler policy change is permitted for the
788 * specified task, returning 0 if permission is granted, -ve if denied.
790 int cap_task_setscheduler(struct task_struct
*p
)
792 return cap_safe_nice(p
);
796 * cap_task_ioprio - Detemine if I/O priority change is permitted
797 * @p: The task to affect
798 * @ioprio: The I/O priority to set
800 * Detemine if the requested I/O priority change is permitted for the specified
801 * task, returning 0 if permission is granted, -ve if denied.
803 int cap_task_setioprio(struct task_struct
*p
, int ioprio
)
805 return cap_safe_nice(p
);
809 * cap_task_ioprio - Detemine if task priority change is permitted
810 * @p: The task to affect
811 * @nice: The nice value to set
813 * Detemine if the requested task priority change is permitted for the
814 * specified task, returning 0 if permission is granted, -ve if denied.
816 int cap_task_setnice(struct task_struct
*p
, int nice
)
818 return cap_safe_nice(p
);
822 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
823 * the current task's bounding set. Returns 0 on success, -ve on error.
825 static long cap_prctl_drop(struct cred
*new, unsigned long cap
)
827 if (!ns_capable(current_user_ns(), CAP_SETPCAP
))
832 cap_lower(new->cap_bset
, cap
);
837 * cap_task_prctl - Implement process control functions for this security module
838 * @option: The process control function requested
839 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
841 * Allow process control functions (sys_prctl()) to alter capabilities; may
842 * also deny access to other functions not otherwise implemented here.
844 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
845 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
846 * modules will consider performing the function.
848 int cap_task_prctl(int option
, unsigned long arg2
, unsigned long arg3
,
849 unsigned long arg4
, unsigned long arg5
)
854 new = prepare_creds();
859 case PR_CAPBSET_READ
:
861 if (!cap_valid(arg2
))
863 error
= !!cap_raised(new->cap_bset
, arg2
);
866 case PR_CAPBSET_DROP
:
867 error
= cap_prctl_drop(new, arg2
);
873 * The next four prctl's remain to assist with transitioning a
874 * system from legacy UID=0 based privilege (when filesystem
875 * capabilities are not in use) to a system using filesystem
876 * capabilities only - as the POSIX.1e draft intended.
880 * PR_SET_SECUREBITS =
881 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
882 * | issecure_mask(SECURE_NOROOT)
883 * | issecure_mask(SECURE_NOROOT_LOCKED)
884 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
885 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
887 * will ensure that the current process and all of its
888 * children will be locked into a pure
889 * capability-based-privilege environment.
891 case PR_SET_SECUREBITS
:
893 if ((((new->securebits
& SECURE_ALL_LOCKS
) >> 1)
894 & (new->securebits
^ arg2
)) /*[1]*/
895 || ((new->securebits
& SECURE_ALL_LOCKS
& ~arg2
)) /*[2]*/
896 || (arg2
& ~(SECURE_ALL_LOCKS
| SECURE_ALL_BITS
)) /*[3]*/
897 || (cap_capable(current_cred(),
898 current_cred()->user_ns
, CAP_SETPCAP
,
899 SECURITY_CAP_AUDIT
) != 0) /*[4]*/
901 * [1] no changing of bits that are locked
902 * [2] no unlocking of locks
903 * [3] no setting of unsupported bits
904 * [4] doing anything requires privilege (go read about
905 * the "sendmail capabilities bug")
908 /* cannot change a locked bit */
910 new->securebits
= arg2
;
913 case PR_GET_SECUREBITS
:
914 error
= new->securebits
;
917 case PR_GET_KEEPCAPS
:
918 if (issecure(SECURE_KEEP_CAPS
))
922 case PR_SET_KEEPCAPS
:
924 if (arg2
> 1) /* Note, we rely on arg2 being unsigned here */
927 if (issecure(SECURE_KEEP_CAPS_LOCKED
))
930 new->securebits
|= issecure_mask(SECURE_KEEP_CAPS
);
932 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
936 /* No functionality available - continue with default */
941 /* Functionality provided */
943 return commit_creds(new);
952 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
953 * @mm: The VM space in which the new mapping is to be made
954 * @pages: The size of the mapping
956 * Determine whether the allocation of a new virtual mapping by the current
957 * task is permitted, returning 0 if permission is granted, -ve if not.
959 int cap_vm_enough_memory(struct mm_struct
*mm
, long pages
)
961 int cap_sys_admin
= 0;
963 if (cap_capable(current_cred(), &init_user_ns
, CAP_SYS_ADMIN
,
964 SECURITY_CAP_NOAUDIT
) == 0)
966 return __vm_enough_memory(mm
, pages
, cap_sys_admin
);
970 * cap_mmap_addr - check if able to map given addr
971 * @addr: address attempting to be mapped
973 * If the process is attempting to map memory below dac_mmap_min_addr they need
974 * CAP_SYS_RAWIO. The other parameters to this function are unused by the
975 * capability security module. Returns 0 if this mapping should be allowed
978 int cap_mmap_addr(unsigned long addr
)
982 if (addr
< dac_mmap_min_addr
) {
983 ret
= cap_capable(current_cred(), &init_user_ns
, CAP_SYS_RAWIO
,
985 /* set PF_SUPERPRIV if it turns out we allow the low mmap */
987 current
->flags
|= PF_SUPERPRIV
;
992 int cap_mmap_file(struct file
*file
, unsigned long reqprot
,
993 unsigned long prot
, unsigned long flags
)
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