0405522995c5742c29d7c792bd9c17cefd40b795
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>
34 #ifdef CONFIG_ANDROID_PARANOID_NETWORK
35 #include <linux/android_aid.h>
39 * If a non-root user executes a setuid-root binary in
40 * !secure(SECURE_NOROOT) mode, then we raise capabilities.
41 * However if fE is also set, then the intent is for only
42 * the file capabilities to be applied, and the setuid-root
43 * bit is left on either to change the uid (plausible) or
44 * to get full privilege on a kernel without file capabilities
45 * support. So in that case we do not raise capabilities.
47 * Warn if that happens, once per boot.
49 static void warn_setuid_and_fcaps_mixed(const char *fname
)
53 printk(KERN_INFO
"warning: `%s' has both setuid-root and"
54 " effective capabilities. Therefore not raising all"
55 " capabilities.\n", fname
);
60 int cap_netlink_send(struct sock
*sk
, struct sk_buff
*skb
)
66 * cap_capable - Determine whether a task has a particular effective capability
67 * @cred: The credentials to use
68 * @ns: The user namespace in which we need the capability
69 * @cap: The capability to check for
70 * @audit: Whether to write an audit message or not
72 * Determine whether the nominated task has the specified capability amongst
73 * its effective set, returning 0 if it does, -ve if it does not.
75 * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable()
76 * and has_capability() functions. That is, it has the reverse semantics:
77 * cap_has_capability() returns 0 when a task has a capability, but the
78 * kernel's capable() and has_capability() returns 1 for this case.
80 int cap_capable(const struct cred
*cred
, struct user_namespace
*targ_ns
,
83 struct user_namespace
*ns
= targ_ns
;
85 #ifdef CONFIG_ANDROID_PARANOID_NETWORK
86 if (cap
== CAP_NET_RAW
&& in_egroup_p(AID_NET_RAW
))
88 if (cap
== CAP_NET_ADMIN
&& in_egroup_p(AID_NET_ADMIN
))
92 /* See if cred has the capability in the target user namespace
93 * by examining the target user namespace and all of the target
94 * user namespace's parents.
97 /* Do we have the necessary capabilities? */
98 if (ns
== cred
->user_ns
)
99 return cap_raised(cred
->cap_effective
, cap
) ? 0 : -EPERM
;
101 /* Have we tried all of the parent namespaces? */
102 if (ns
== &init_user_ns
)
106 * The owner of the user namespace in the parent of the
107 * user namespace has all caps.
109 if ((ns
->parent
== cred
->user_ns
) && uid_eq(ns
->owner
, cred
->euid
))
113 * If you have a capability in a parent user ns, then you have
114 * it over all children user namespaces as well.
119 /* We never get here */
123 * cap_settime - Determine whether the current process may set the system clock
124 * @ts: The time to set
125 * @tz: The timezone to set
127 * Determine whether the current process may set the system clock and timezone
128 * information, returning 0 if permission granted, -ve if denied.
130 int cap_settime(const struct timespec
*ts
, const struct timezone
*tz
)
132 if (!capable(CAP_SYS_TIME
))
138 * cap_ptrace_access_check - Determine whether the current process may access
140 * @child: The process to be accessed
141 * @mode: The mode of attachment.
143 * If we are in the same or an ancestor user_ns and have all the target
144 * task's capabilities, then ptrace access is allowed.
145 * If we have the ptrace capability to the target user_ns, then ptrace
149 * Determine whether a process may access another, returning 0 if permission
150 * granted, -ve if denied.
152 int cap_ptrace_access_check(struct task_struct
*child
, unsigned int mode
)
155 const struct cred
*cred
, *child_cred
;
158 cred
= current_cred();
159 child_cred
= __task_cred(child
);
160 if (cred
->user_ns
== child_cred
->user_ns
&&
161 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
163 if (ns_capable(child_cred
->user_ns
, CAP_SYS_PTRACE
))
172 * cap_ptrace_traceme - Determine whether another process may trace the current
173 * @parent: The task proposed to be the tracer
175 * If parent is in the same or an ancestor user_ns and has all current's
176 * capabilities, then ptrace access is allowed.
177 * If parent has the ptrace capability to current's user_ns, then ptrace
181 * Determine whether the nominated task is permitted to trace the current
182 * process, returning 0 if permission is granted, -ve if denied.
184 int cap_ptrace_traceme(struct task_struct
*parent
)
187 const struct cred
*cred
, *child_cred
;
190 cred
= __task_cred(parent
);
191 child_cred
= current_cred();
192 if (cred
->user_ns
== child_cred
->user_ns
&&
193 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
195 if (has_ns_capability(parent
, child_cred
->user_ns
, CAP_SYS_PTRACE
))
204 * cap_capget - Retrieve a task's capability sets
205 * @target: The task from which to retrieve the capability sets
206 * @effective: The place to record the effective set
207 * @inheritable: The place to record the inheritable set
208 * @permitted: The place to record the permitted set
210 * This function retrieves the capabilities of the nominated task and returns
211 * them to the caller.
213 int cap_capget(struct task_struct
*target
, kernel_cap_t
*effective
,
214 kernel_cap_t
*inheritable
, kernel_cap_t
*permitted
)
216 const struct cred
*cred
;
218 /* Derived from kernel/capability.c:sys_capget. */
220 cred
= __task_cred(target
);
221 *effective
= cred
->cap_effective
;
222 *inheritable
= cred
->cap_inheritable
;
223 *permitted
= cred
->cap_permitted
;
229 * Determine whether the inheritable capabilities are limited to the old
230 * permitted set. Returns 1 if they are limited, 0 if they are not.
232 static inline int cap_inh_is_capped(void)
235 /* they are so limited unless the current task has the CAP_SETPCAP
238 if (cap_capable(current_cred(), current_cred()->user_ns
,
239 CAP_SETPCAP
, SECURITY_CAP_AUDIT
) == 0)
245 * cap_capset - Validate and apply proposed changes to current's capabilities
246 * @new: The proposed new credentials; alterations should be made here
247 * @old: The current task's current credentials
248 * @effective: A pointer to the proposed new effective capabilities set
249 * @inheritable: A pointer to the proposed new inheritable capabilities set
250 * @permitted: A pointer to the proposed new permitted capabilities set
252 * This function validates and applies a proposed mass change to the current
253 * process's capability sets. The changes are made to the proposed new
254 * credentials, and assuming no error, will be committed by the caller of LSM.
256 int cap_capset(struct cred
*new,
257 const struct cred
*old
,
258 const kernel_cap_t
*effective
,
259 const kernel_cap_t
*inheritable
,
260 const kernel_cap_t
*permitted
)
262 if (cap_inh_is_capped() &&
263 !cap_issubset(*inheritable
,
264 cap_combine(old
->cap_inheritable
,
265 old
->cap_permitted
)))
266 /* incapable of using this inheritable set */
269 if (!cap_issubset(*inheritable
,
270 cap_combine(old
->cap_inheritable
,
272 /* no new pI capabilities outside bounding set */
275 /* verify restrictions on target's new Permitted set */
276 if (!cap_issubset(*permitted
, old
->cap_permitted
))
279 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
280 if (!cap_issubset(*effective
, *permitted
))
283 new->cap_effective
= *effective
;
284 new->cap_inheritable
= *inheritable
;
285 new->cap_permitted
= *permitted
;
290 * Clear proposed capability sets for execve().
292 static inline void bprm_clear_caps(struct linux_binprm
*bprm
)
294 cap_clear(bprm
->cred
->cap_permitted
);
295 bprm
->cap_effective
= false;
299 * cap_inode_need_killpriv - Determine if inode change affects privileges
300 * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
302 * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
303 * affects the security markings on that inode, and if it is, should
304 * inode_killpriv() be invoked or the change rejected?
306 * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
307 * -ve to deny the change.
309 int cap_inode_need_killpriv(struct dentry
*dentry
)
311 struct inode
*inode
= dentry
->d_inode
;
314 if (!inode
->i_op
->getxattr
)
317 error
= inode
->i_op
->getxattr(dentry
, XATTR_NAME_CAPS
, NULL
, 0);
324 * cap_inode_killpriv - Erase the security markings on an inode
325 * @dentry: The inode/dentry to alter
327 * Erase the privilege-enhancing security markings on an inode.
329 * Returns 0 if successful, -ve on error.
331 int cap_inode_killpriv(struct dentry
*dentry
)
333 struct inode
*inode
= dentry
->d_inode
;
335 if (!inode
->i_op
->removexattr
)
338 return inode
->i_op
->removexattr(dentry
, XATTR_NAME_CAPS
);
342 * Calculate the new process capability sets from the capability sets attached
345 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data
*caps
,
346 struct linux_binprm
*bprm
,
350 struct cred
*new = bprm
->cred
;
354 if (caps
->magic_etc
& VFS_CAP_FLAGS_EFFECTIVE
)
357 if (caps
->magic_etc
& VFS_CAP_REVISION_MASK
)
360 CAP_FOR_EACH_U32(i
) {
361 __u32 permitted
= caps
->permitted
.cap
[i
];
362 __u32 inheritable
= caps
->inheritable
.cap
[i
];
365 * pP' = (X & fP) | (pI & fI)
367 new->cap_permitted
.cap
[i
] =
368 (new->cap_bset
.cap
[i
] & permitted
) |
369 (new->cap_inheritable
.cap
[i
] & inheritable
);
371 if (permitted
& ~new->cap_permitted
.cap
[i
])
372 /* insufficient to execute correctly */
377 * For legacy apps, with no internal support for recognizing they
378 * do not have enough capabilities, we return an error if they are
379 * missing some "forced" (aka file-permitted) capabilities.
381 return *effective
? ret
: 0;
385 * Extract the on-exec-apply capability sets for an executable file.
387 int get_vfs_caps_from_disk(const struct dentry
*dentry
, struct cpu_vfs_cap_data
*cpu_caps
)
389 struct inode
*inode
= dentry
->d_inode
;
393 struct vfs_cap_data caps
;
395 memset(cpu_caps
, 0, sizeof(struct cpu_vfs_cap_data
));
397 if (!inode
|| !inode
->i_op
->getxattr
)
400 size
= inode
->i_op
->getxattr((struct dentry
*)dentry
, XATTR_NAME_CAPS
, &caps
,
402 if (size
== -ENODATA
|| size
== -EOPNOTSUPP
)
403 /* no data, that's ok */
408 if (size
< sizeof(magic_etc
))
411 cpu_caps
->magic_etc
= magic_etc
= le32_to_cpu(caps
.magic_etc
);
413 switch (magic_etc
& VFS_CAP_REVISION_MASK
) {
414 case VFS_CAP_REVISION_1
:
415 if (size
!= XATTR_CAPS_SZ_1
)
417 tocopy
= VFS_CAP_U32_1
;
419 case VFS_CAP_REVISION_2
:
420 if (size
!= XATTR_CAPS_SZ_2
)
422 tocopy
= VFS_CAP_U32_2
;
428 CAP_FOR_EACH_U32(i
) {
431 cpu_caps
->permitted
.cap
[i
] = le32_to_cpu(caps
.data
[i
].permitted
);
432 cpu_caps
->inheritable
.cap
[i
] = le32_to_cpu(caps
.data
[i
].inheritable
);
435 cpu_caps
->permitted
.cap
[CAP_LAST_U32
] &= CAP_LAST_U32_VALID_MASK
;
436 cpu_caps
->inheritable
.cap
[CAP_LAST_U32
] &= CAP_LAST_U32_VALID_MASK
;
442 * Attempt to get the on-exec apply capability sets for an executable file from
443 * its xattrs and, if present, apply them to the proposed credentials being
444 * constructed by execve().
446 static int get_file_caps(struct linux_binprm
*bprm
, bool *effective
, bool *has_cap
)
448 struct dentry
*dentry
;
450 struct cpu_vfs_cap_data vcaps
;
452 bprm_clear_caps(bprm
);
454 if (!file_caps_enabled
)
457 if (bprm
->file
->f_path
.mnt
->mnt_flags
& MNT_NOSUID
)
460 dentry
= dget(bprm
->file
->f_dentry
);
462 rc
= get_vfs_caps_from_disk(dentry
, &vcaps
);
465 printk(KERN_NOTICE
"%s: get_vfs_caps_from_disk returned %d for %s\n",
466 __func__
, rc
, bprm
->filename
);
467 else if (rc
== -ENODATA
)
472 rc
= bprm_caps_from_vfs_caps(&vcaps
, bprm
, effective
, has_cap
);
474 printk(KERN_NOTICE
"%s: cap_from_disk returned %d for %s\n",
475 __func__
, rc
, bprm
->filename
);
480 bprm_clear_caps(bprm
);
486 * cap_bprm_set_creds - Set up the proposed credentials for execve().
487 * @bprm: The execution parameters, including the proposed creds
489 * Set up the proposed credentials for a new execution context being
490 * constructed by execve(). The proposed creds in @bprm->cred is altered,
491 * which won't take effect immediately. Returns 0 if successful, -ve on error.
493 int cap_bprm_set_creds(struct linux_binprm
*bprm
)
495 const struct cred
*old
= current_cred();
496 struct cred
*new = bprm
->cred
;
497 bool effective
, has_cap
= false;
502 ret
= get_file_caps(bprm
, &effective
, &has_cap
);
506 root_uid
= make_kuid(new->user_ns
, 0);
508 if (!issecure(SECURE_NOROOT
)) {
510 * If the legacy file capability is set, then don't set privs
511 * for a setuid root binary run by a non-root user. Do set it
512 * for a root user just to cause least surprise to an admin.
514 if (has_cap
&& !uid_eq(new->uid
, root_uid
) && uid_eq(new->euid
, root_uid
)) {
515 warn_setuid_and_fcaps_mixed(bprm
->filename
);
519 * To support inheritance of root-permissions and suid-root
520 * executables under compatibility mode, we override the
521 * capability sets for the file.
523 * If only the real uid is 0, we do not set the effective bit.
525 if (uid_eq(new->euid
, root_uid
) || uid_eq(new->uid
, root_uid
)) {
526 /* pP' = (cap_bset & ~0) | (pI & ~0) */
527 new->cap_permitted
= cap_combine(old
->cap_bset
,
528 old
->cap_inheritable
);
530 if (uid_eq(new->euid
, root_uid
))
535 /* if we have fs caps, clear dangerous personality flags */
536 if (!cap_issubset(new->cap_permitted
, old
->cap_permitted
))
537 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
540 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
541 * credentials unless they have the appropriate permit.
543 * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
545 if ((!uid_eq(new->euid
, old
->uid
) ||
546 !gid_eq(new->egid
, old
->gid
) ||
547 !cap_issubset(new->cap_permitted
, old
->cap_permitted
)) &&
548 bprm
->unsafe
& ~LSM_UNSAFE_PTRACE_CAP
) {
549 /* downgrade; they get no more than they had, and maybe less */
550 if (!capable(CAP_SETUID
) ||
551 (bprm
->unsafe
& LSM_UNSAFE_NO_NEW_PRIVS
)) {
552 new->euid
= new->uid
;
553 new->egid
= new->gid
;
555 new->cap_permitted
= cap_intersect(new->cap_permitted
,
559 new->suid
= new->fsuid
= new->euid
;
560 new->sgid
= new->fsgid
= new->egid
;
563 new->cap_effective
= new->cap_permitted
;
565 cap_clear(new->cap_effective
);
566 bprm
->cap_effective
= effective
;
569 * Audit candidate if current->cap_effective is set
571 * We do not bother to audit if 3 things are true:
572 * 1) cap_effective has all caps
574 * 3) root is supposed to have all caps (SECURE_NOROOT)
575 * Since this is just a normal root execing a process.
577 * Number 1 above might fail if you don't have a full bset, but I think
578 * that is interesting information to audit.
580 if (!cap_isclear(new->cap_effective
)) {
581 if (!cap_issubset(CAP_FULL_SET
, new->cap_effective
) ||
582 !uid_eq(new->euid
, root_uid
) || !uid_eq(new->uid
, root_uid
) ||
583 issecure(SECURE_NOROOT
)) {
584 ret
= audit_log_bprm_fcaps(bprm
, new, old
);
590 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
595 * cap_bprm_secureexec - Determine whether a secure execution is required
596 * @bprm: The execution parameters
598 * Determine whether a secure execution is required, return 1 if it is, and 0
601 * The credentials have been committed by this point, and so are no longer
602 * available through @bprm->cred.
604 int cap_bprm_secureexec(struct linux_binprm
*bprm
)
606 const struct cred
*cred
= current_cred();
607 kuid_t root_uid
= make_kuid(cred
->user_ns
, 0);
609 if (!uid_eq(cred
->uid
, root_uid
)) {
610 if (bprm
->cap_effective
)
612 if (!cap_isclear(cred
->cap_permitted
))
616 return (!uid_eq(cred
->euid
, cred
->uid
) ||
617 !gid_eq(cred
->egid
, cred
->gid
));
621 * cap_inode_setxattr - Determine whether an xattr may be altered
622 * @dentry: The inode/dentry being altered
623 * @name: The name of the xattr to be changed
624 * @value: The value that the xattr will be changed to
625 * @size: The size of value
626 * @flags: The replacement flag
628 * Determine whether an xattr may be altered or set on an inode, returning 0 if
629 * permission is granted, -ve if denied.
631 * This is used to make sure security xattrs don't get updated or set by those
632 * who aren't privileged to do so.
634 int cap_inode_setxattr(struct dentry
*dentry
, const char *name
,
635 const void *value
, size_t size
, int flags
)
637 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
638 if (!capable(CAP_SETFCAP
))
643 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
644 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
645 !capable(CAP_SYS_ADMIN
))
651 * cap_inode_removexattr - Determine whether an xattr may be removed
652 * @dentry: The inode/dentry being altered
653 * @name: The name of the xattr to be changed
655 * Determine whether an xattr may be removed from an inode, returning 0 if
656 * permission is granted, -ve if denied.
658 * This is used to make sure security xattrs don't get removed by those who
659 * aren't privileged to remove them.
661 int cap_inode_removexattr(struct dentry
*dentry
, const char *name
)
663 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
664 if (!capable(CAP_SETFCAP
))
669 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
670 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
671 !capable(CAP_SYS_ADMIN
))
677 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
678 * a process after a call to setuid, setreuid, or setresuid.
680 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
681 * {r,e,s}uid != 0, the permitted and effective capabilities are
684 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
685 * capabilities of the process are cleared.
687 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
688 * capabilities are set to the permitted capabilities.
690 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
695 * cevans - New behaviour, Oct '99
696 * A process may, via prctl(), elect to keep its capabilities when it
697 * calls setuid() and switches away from uid==0. Both permitted and
698 * effective sets will be retained.
699 * Without this change, it was impossible for a daemon to drop only some
700 * of its privilege. The call to setuid(!=0) would drop all privileges!
701 * Keeping uid 0 is not an option because uid 0 owns too many vital
703 * Thanks to Olaf Kirch and Peter Benie for spotting this.
705 static inline void cap_emulate_setxuid(struct cred
*new, const struct cred
*old
)
707 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
709 if ((uid_eq(old
->uid
, root_uid
) ||
710 uid_eq(old
->euid
, root_uid
) ||
711 uid_eq(old
->suid
, root_uid
)) &&
712 (!uid_eq(new->uid
, root_uid
) &&
713 !uid_eq(new->euid
, root_uid
) &&
714 !uid_eq(new->suid
, root_uid
)) &&
715 !issecure(SECURE_KEEP_CAPS
)) {
716 cap_clear(new->cap_permitted
);
717 cap_clear(new->cap_effective
);
719 if (uid_eq(old
->euid
, root_uid
) && !uid_eq(new->euid
, root_uid
))
720 cap_clear(new->cap_effective
);
721 if (!uid_eq(old
->euid
, root_uid
) && uid_eq(new->euid
, root_uid
))
722 new->cap_effective
= new->cap_permitted
;
726 * cap_task_fix_setuid - Fix up the results of setuid() call
727 * @new: The proposed credentials
728 * @old: The current task's current credentials
729 * @flags: Indications of what has changed
731 * Fix up the results of setuid() call before the credential changes are
732 * actually applied, returning 0 to grant the changes, -ve to deny them.
734 int cap_task_fix_setuid(struct cred
*new, const struct cred
*old
, int flags
)
740 /* juggle the capabilities to follow [RES]UID changes unless
741 * otherwise suppressed */
742 if (!issecure(SECURE_NO_SETUID_FIXUP
))
743 cap_emulate_setxuid(new, old
);
747 /* juggle the capabilties to follow FSUID changes, unless
748 * otherwise suppressed
750 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
751 * if not, we might be a bit too harsh here.
753 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
754 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
755 if (uid_eq(old
->fsuid
, root_uid
) && !uid_eq(new->fsuid
, root_uid
))
757 cap_drop_fs_set(new->cap_effective
);
759 if (!uid_eq(old
->fsuid
, root_uid
) && uid_eq(new->fsuid
, root_uid
))
761 cap_raise_fs_set(new->cap_effective
,
774 * Rationale: code calling task_setscheduler, task_setioprio, and
775 * task_setnice, assumes that
776 * . if capable(cap_sys_nice), then those actions should be allowed
777 * . if not capable(cap_sys_nice), but acting on your own processes,
778 * then those actions should be allowed
779 * This is insufficient now since you can call code without suid, but
780 * yet with increased caps.
781 * So we check for increased caps on the target process.
783 static int cap_safe_nice(struct task_struct
*p
)
788 is_subset
= cap_issubset(__task_cred(p
)->cap_permitted
,
789 current_cred()->cap_permitted
);
792 if (!is_subset
&& !capable(CAP_SYS_NICE
))
798 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
799 * @p: The task to affect
801 * Detemine if the requested scheduler policy change is permitted for the
802 * specified task, returning 0 if permission is granted, -ve if denied.
804 int cap_task_setscheduler(struct task_struct
*p
)
806 return cap_safe_nice(p
);
810 * cap_task_ioprio - Detemine if I/O priority change is permitted
811 * @p: The task to affect
812 * @ioprio: The I/O priority to set
814 * Detemine if the requested I/O priority change is permitted for the specified
815 * task, returning 0 if permission is granted, -ve if denied.
817 int cap_task_setioprio(struct task_struct
*p
, int ioprio
)
819 return cap_safe_nice(p
);
823 * cap_task_ioprio - Detemine if task priority change is permitted
824 * @p: The task to affect
825 * @nice: The nice value to set
827 * Detemine if the requested task priority change is permitted for the
828 * specified task, returning 0 if permission is granted, -ve if denied.
830 int cap_task_setnice(struct task_struct
*p
, int nice
)
832 return cap_safe_nice(p
);
836 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
837 * the current task's bounding set. Returns 0 on success, -ve on error.
839 static long cap_prctl_drop(struct cred
*new, unsigned long cap
)
841 if (!capable(CAP_SETPCAP
))
846 cap_lower(new->cap_bset
, cap
);
851 * cap_task_prctl - Implement process control functions for this security module
852 * @option: The process control function requested
853 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
855 * Allow process control functions (sys_prctl()) to alter capabilities; may
856 * also deny access to other functions not otherwise implemented here.
858 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
859 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
860 * modules will consider performing the function.
862 int cap_task_prctl(int option
, unsigned long arg2
, unsigned long arg3
,
863 unsigned long arg4
, unsigned long arg5
)
868 new = prepare_creds();
873 case PR_CAPBSET_READ
:
875 if (!cap_valid(arg2
))
877 error
= !!cap_raised(new->cap_bset
, arg2
);
880 case PR_CAPBSET_DROP
:
881 error
= cap_prctl_drop(new, arg2
);
887 * The next four prctl's remain to assist with transitioning a
888 * system from legacy UID=0 based privilege (when filesystem
889 * capabilities are not in use) to a system using filesystem
890 * capabilities only - as the POSIX.1e draft intended.
894 * PR_SET_SECUREBITS =
895 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
896 * | issecure_mask(SECURE_NOROOT)
897 * | issecure_mask(SECURE_NOROOT_LOCKED)
898 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
899 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
901 * will ensure that the current process and all of its
902 * children will be locked into a pure
903 * capability-based-privilege environment.
905 case PR_SET_SECUREBITS
:
907 if ((((new->securebits
& SECURE_ALL_LOCKS
) >> 1)
908 & (new->securebits
^ arg2
)) /*[1]*/
909 || ((new->securebits
& SECURE_ALL_LOCKS
& ~arg2
)) /*[2]*/
910 || (arg2
& ~(SECURE_ALL_LOCKS
| SECURE_ALL_BITS
)) /*[3]*/
911 || (cap_capable(current_cred(),
912 current_cred()->user_ns
, CAP_SETPCAP
,
913 SECURITY_CAP_AUDIT
) != 0) /*[4]*/
915 * [1] no changing of bits that are locked
916 * [2] no unlocking of locks
917 * [3] no setting of unsupported bits
918 * [4] doing anything requires privilege (go read about
919 * the "sendmail capabilities bug")
922 /* cannot change a locked bit */
924 new->securebits
= arg2
;
927 case PR_GET_SECUREBITS
:
928 error
= new->securebits
;
931 case PR_GET_KEEPCAPS
:
932 if (issecure(SECURE_KEEP_CAPS
))
936 case PR_SET_KEEPCAPS
:
938 if (arg2
> 1) /* Note, we rely on arg2 being unsigned here */
941 if (issecure(SECURE_KEEP_CAPS_LOCKED
))
944 new->securebits
|= issecure_mask(SECURE_KEEP_CAPS
);
946 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
950 /* No functionality available - continue with default */
955 /* Functionality provided */
957 return commit_creds(new);
966 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
967 * @mm: The VM space in which the new mapping is to be made
968 * @pages: The size of the mapping
970 * Determine whether the allocation of a new virtual mapping by the current
971 * task is permitted, returning 0 if permission is granted, -ve if not.
973 int cap_vm_enough_memory(struct mm_struct
*mm
, long pages
)
975 int cap_sys_admin
= 0;
977 if (cap_capable(current_cred(), &init_user_ns
, CAP_SYS_ADMIN
,
978 SECURITY_CAP_NOAUDIT
) == 0)
980 return __vm_enough_memory(mm
, pages
, cap_sys_admin
);
984 * cap_mmap_addr - check if able to map given addr
985 * @addr: address attempting to be mapped
987 * If the process is attempting to map memory below dac_mmap_min_addr they need
988 * CAP_SYS_RAWIO. The other parameters to this function are unused by the
989 * capability security module. Returns 0 if this mapping should be allowed
992 int cap_mmap_addr(unsigned long addr
)
996 if (addr
< dac_mmap_min_addr
) {
997 ret
= cap_capable(current_cred(), &init_user_ns
, CAP_SYS_RAWIO
,
999 /* set PF_SUPERPRIV if it turns out we allow the low mmap */
1001 current
->flags
|= PF_SUPERPRIV
;
1006 int cap_mmap_file(struct file
*file
, unsigned long reqprot
,
1007 unsigned long prot
, unsigned long flags
)