5870fdc224b436d954f240a546b5398bbc3ce028
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
);
439 * Attempt to get the on-exec apply capability sets for an executable file from
440 * its xattrs and, if present, apply them to the proposed credentials being
441 * constructed by execve().
443 static int get_file_caps(struct linux_binprm
*bprm
, bool *effective
, bool *has_cap
)
445 struct dentry
*dentry
;
447 struct cpu_vfs_cap_data vcaps
;
449 bprm_clear_caps(bprm
);
451 if (!file_caps_enabled
)
454 if (bprm
->file
->f_path
.mnt
->mnt_flags
& MNT_NOSUID
)
457 dentry
= dget(bprm
->file
->f_dentry
);
459 rc
= get_vfs_caps_from_disk(dentry
, &vcaps
);
462 printk(KERN_NOTICE
"%s: get_vfs_caps_from_disk returned %d for %s\n",
463 __func__
, rc
, bprm
->filename
);
464 else if (rc
== -ENODATA
)
469 rc
= bprm_caps_from_vfs_caps(&vcaps
, bprm
, effective
, has_cap
);
471 printk(KERN_NOTICE
"%s: cap_from_disk returned %d for %s\n",
472 __func__
, rc
, bprm
->filename
);
477 bprm_clear_caps(bprm
);
483 * cap_bprm_set_creds - Set up the proposed credentials for execve().
484 * @bprm: The execution parameters, including the proposed creds
486 * Set up the proposed credentials for a new execution context being
487 * constructed by execve(). The proposed creds in @bprm->cred is altered,
488 * which won't take effect immediately. Returns 0 if successful, -ve on error.
490 int cap_bprm_set_creds(struct linux_binprm
*bprm
)
492 const struct cred
*old
= current_cred();
493 struct cred
*new = bprm
->cred
;
494 bool effective
, has_cap
= false;
499 ret
= get_file_caps(bprm
, &effective
, &has_cap
);
503 root_uid
= make_kuid(new->user_ns
, 0);
505 if (!issecure(SECURE_NOROOT
)) {
507 * If the legacy file capability is set, then don't set privs
508 * for a setuid root binary run by a non-root user. Do set it
509 * for a root user just to cause least surprise to an admin.
511 if (has_cap
&& !uid_eq(new->uid
, root_uid
) && uid_eq(new->euid
, root_uid
)) {
512 warn_setuid_and_fcaps_mixed(bprm
->filename
);
516 * To support inheritance of root-permissions and suid-root
517 * executables under compatibility mode, we override the
518 * capability sets for the file.
520 * If only the real uid is 0, we do not set the effective bit.
522 if (uid_eq(new->euid
, root_uid
) || uid_eq(new->uid
, root_uid
)) {
523 /* pP' = (cap_bset & ~0) | (pI & ~0) */
524 new->cap_permitted
= cap_combine(old
->cap_bset
,
525 old
->cap_inheritable
);
527 if (uid_eq(new->euid
, root_uid
))
532 /* if we have fs caps, clear dangerous personality flags */
533 if (!cap_issubset(new->cap_permitted
, old
->cap_permitted
))
534 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
537 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
538 * credentials unless they have the appropriate permit.
540 * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
542 if ((!uid_eq(new->euid
, old
->uid
) ||
543 !gid_eq(new->egid
, old
->gid
) ||
544 !cap_issubset(new->cap_permitted
, old
->cap_permitted
)) &&
545 bprm
->unsafe
& ~LSM_UNSAFE_PTRACE_CAP
) {
546 /* downgrade; they get no more than they had, and maybe less */
547 if (!capable(CAP_SETUID
) ||
548 (bprm
->unsafe
& LSM_UNSAFE_NO_NEW_PRIVS
)) {
549 new->euid
= new->uid
;
550 new->egid
= new->gid
;
552 new->cap_permitted
= cap_intersect(new->cap_permitted
,
556 new->suid
= new->fsuid
= new->euid
;
557 new->sgid
= new->fsgid
= new->egid
;
560 new->cap_effective
= new->cap_permitted
;
562 cap_clear(new->cap_effective
);
563 bprm
->cap_effective
= effective
;
566 * Audit candidate if current->cap_effective is set
568 * We do not bother to audit if 3 things are true:
569 * 1) cap_effective has all caps
571 * 3) root is supposed to have all caps (SECURE_NOROOT)
572 * Since this is just a normal root execing a process.
574 * Number 1 above might fail if you don't have a full bset, but I think
575 * that is interesting information to audit.
577 if (!cap_isclear(new->cap_effective
)) {
578 if (!cap_issubset(CAP_FULL_SET
, new->cap_effective
) ||
579 !uid_eq(new->euid
, root_uid
) || !uid_eq(new->uid
, root_uid
) ||
580 issecure(SECURE_NOROOT
)) {
581 ret
= audit_log_bprm_fcaps(bprm
, new, old
);
587 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
592 * cap_bprm_secureexec - Determine whether a secure execution is required
593 * @bprm: The execution parameters
595 * Determine whether a secure execution is required, return 1 if it is, and 0
598 * The credentials have been committed by this point, and so are no longer
599 * available through @bprm->cred.
601 int cap_bprm_secureexec(struct linux_binprm
*bprm
)
603 const struct cred
*cred
= current_cred();
604 kuid_t root_uid
= make_kuid(cred
->user_ns
, 0);
606 if (!uid_eq(cred
->uid
, root_uid
)) {
607 if (bprm
->cap_effective
)
609 if (!cap_isclear(cred
->cap_permitted
))
613 return (!uid_eq(cred
->euid
, cred
->uid
) ||
614 !gid_eq(cred
->egid
, cred
->gid
));
618 * cap_inode_setxattr - Determine whether an xattr may be altered
619 * @dentry: The inode/dentry being altered
620 * @name: The name of the xattr to be changed
621 * @value: The value that the xattr will be changed to
622 * @size: The size of value
623 * @flags: The replacement flag
625 * Determine whether an xattr may be altered or set on an inode, returning 0 if
626 * permission is granted, -ve if denied.
628 * This is used to make sure security xattrs don't get updated or set by those
629 * who aren't privileged to do so.
631 int cap_inode_setxattr(struct dentry
*dentry
, const char *name
,
632 const void *value
, size_t size
, int flags
)
634 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
635 if (!capable(CAP_SETFCAP
))
640 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
641 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
642 !capable(CAP_SYS_ADMIN
))
648 * cap_inode_removexattr - Determine whether an xattr may be removed
649 * @dentry: The inode/dentry being altered
650 * @name: The name of the xattr to be changed
652 * Determine whether an xattr may be removed from an inode, returning 0 if
653 * permission is granted, -ve if denied.
655 * This is used to make sure security xattrs don't get removed by those who
656 * aren't privileged to remove them.
658 int cap_inode_removexattr(struct dentry
*dentry
, const char *name
)
660 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
661 if (!capable(CAP_SETFCAP
))
666 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
667 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
668 !capable(CAP_SYS_ADMIN
))
674 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
675 * a process after a call to setuid, setreuid, or setresuid.
677 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
678 * {r,e,s}uid != 0, the permitted and effective capabilities are
681 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
682 * capabilities of the process are cleared.
684 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
685 * capabilities are set to the permitted capabilities.
687 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
692 * cevans - New behaviour, Oct '99
693 * A process may, via prctl(), elect to keep its capabilities when it
694 * calls setuid() and switches away from uid==0. Both permitted and
695 * effective sets will be retained.
696 * Without this change, it was impossible for a daemon to drop only some
697 * of its privilege. The call to setuid(!=0) would drop all privileges!
698 * Keeping uid 0 is not an option because uid 0 owns too many vital
700 * Thanks to Olaf Kirch and Peter Benie for spotting this.
702 static inline void cap_emulate_setxuid(struct cred
*new, const struct cred
*old
)
704 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
706 if ((uid_eq(old
->uid
, root_uid
) ||
707 uid_eq(old
->euid
, root_uid
) ||
708 uid_eq(old
->suid
, root_uid
)) &&
709 (!uid_eq(new->uid
, root_uid
) &&
710 !uid_eq(new->euid
, root_uid
) &&
711 !uid_eq(new->suid
, root_uid
)) &&
712 !issecure(SECURE_KEEP_CAPS
)) {
713 cap_clear(new->cap_permitted
);
714 cap_clear(new->cap_effective
);
716 if (uid_eq(old
->euid
, root_uid
) && !uid_eq(new->euid
, root_uid
))
717 cap_clear(new->cap_effective
);
718 if (!uid_eq(old
->euid
, root_uid
) && uid_eq(new->euid
, root_uid
))
719 new->cap_effective
= new->cap_permitted
;
723 * cap_task_fix_setuid - Fix up the results of setuid() call
724 * @new: The proposed credentials
725 * @old: The current task's current credentials
726 * @flags: Indications of what has changed
728 * Fix up the results of setuid() call before the credential changes are
729 * actually applied, returning 0 to grant the changes, -ve to deny them.
731 int cap_task_fix_setuid(struct cred
*new, const struct cred
*old
, int flags
)
737 /* juggle the capabilities to follow [RES]UID changes unless
738 * otherwise suppressed */
739 if (!issecure(SECURE_NO_SETUID_FIXUP
))
740 cap_emulate_setxuid(new, old
);
744 /* juggle the capabilties to follow FSUID changes, unless
745 * otherwise suppressed
747 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
748 * if not, we might be a bit too harsh here.
750 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
751 kuid_t root_uid
= make_kuid(old
->user_ns
, 0);
752 if (uid_eq(old
->fsuid
, root_uid
) && !uid_eq(new->fsuid
, root_uid
))
754 cap_drop_fs_set(new->cap_effective
);
756 if (!uid_eq(old
->fsuid
, root_uid
) && uid_eq(new->fsuid
, root_uid
))
758 cap_raise_fs_set(new->cap_effective
,
771 * Rationale: code calling task_setscheduler, task_setioprio, and
772 * task_setnice, assumes that
773 * . if capable(cap_sys_nice), then those actions should be allowed
774 * . if not capable(cap_sys_nice), but acting on your own processes,
775 * then those actions should be allowed
776 * This is insufficient now since you can call code without suid, but
777 * yet with increased caps.
778 * So we check for increased caps on the target process.
780 static int cap_safe_nice(struct task_struct
*p
)
785 is_subset
= cap_issubset(__task_cred(p
)->cap_permitted
,
786 current_cred()->cap_permitted
);
789 if (!is_subset
&& !capable(CAP_SYS_NICE
))
795 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
796 * @p: The task to affect
798 * Detemine if the requested scheduler policy change is permitted for the
799 * specified task, returning 0 if permission is granted, -ve if denied.
801 int cap_task_setscheduler(struct task_struct
*p
)
803 return cap_safe_nice(p
);
807 * cap_task_ioprio - Detemine if I/O priority change is permitted
808 * @p: The task to affect
809 * @ioprio: The I/O priority to set
811 * Detemine if the requested I/O priority change is permitted for the specified
812 * task, returning 0 if permission is granted, -ve if denied.
814 int cap_task_setioprio(struct task_struct
*p
, int ioprio
)
816 return cap_safe_nice(p
);
820 * cap_task_ioprio - Detemine if task priority change is permitted
821 * @p: The task to affect
822 * @nice: The nice value to set
824 * Detemine if the requested task priority change is permitted for the
825 * specified task, returning 0 if permission is granted, -ve if denied.
827 int cap_task_setnice(struct task_struct
*p
, int nice
)
829 return cap_safe_nice(p
);
833 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
834 * the current task's bounding set. Returns 0 on success, -ve on error.
836 static long cap_prctl_drop(struct cred
*new, unsigned long cap
)
838 if (!capable(CAP_SETPCAP
))
843 cap_lower(new->cap_bset
, cap
);
848 * cap_task_prctl - Implement process control functions for this security module
849 * @option: The process control function requested
850 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
852 * Allow process control functions (sys_prctl()) to alter capabilities; may
853 * also deny access to other functions not otherwise implemented here.
855 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
856 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
857 * modules will consider performing the function.
859 int cap_task_prctl(int option
, unsigned long arg2
, unsigned long arg3
,
860 unsigned long arg4
, unsigned long arg5
)
865 new = prepare_creds();
870 case PR_CAPBSET_READ
:
872 if (!cap_valid(arg2
))
874 error
= !!cap_raised(new->cap_bset
, arg2
);
877 case PR_CAPBSET_DROP
:
878 error
= cap_prctl_drop(new, arg2
);
884 * The next four prctl's remain to assist with transitioning a
885 * system from legacy UID=0 based privilege (when filesystem
886 * capabilities are not in use) to a system using filesystem
887 * capabilities only - as the POSIX.1e draft intended.
891 * PR_SET_SECUREBITS =
892 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
893 * | issecure_mask(SECURE_NOROOT)
894 * | issecure_mask(SECURE_NOROOT_LOCKED)
895 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
896 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
898 * will ensure that the current process and all of its
899 * children will be locked into a pure
900 * capability-based-privilege environment.
902 case PR_SET_SECUREBITS
:
904 if ((((new->securebits
& SECURE_ALL_LOCKS
) >> 1)
905 & (new->securebits
^ arg2
)) /*[1]*/
906 || ((new->securebits
& SECURE_ALL_LOCKS
& ~arg2
)) /*[2]*/
907 || (arg2
& ~(SECURE_ALL_LOCKS
| SECURE_ALL_BITS
)) /*[3]*/
908 || (cap_capable(current_cred(),
909 current_cred()->user_ns
, CAP_SETPCAP
,
910 SECURITY_CAP_AUDIT
) != 0) /*[4]*/
912 * [1] no changing of bits that are locked
913 * [2] no unlocking of locks
914 * [3] no setting of unsupported bits
915 * [4] doing anything requires privilege (go read about
916 * the "sendmail capabilities bug")
919 /* cannot change a locked bit */
921 new->securebits
= arg2
;
924 case PR_GET_SECUREBITS
:
925 error
= new->securebits
;
928 case PR_GET_KEEPCAPS
:
929 if (issecure(SECURE_KEEP_CAPS
))
933 case PR_SET_KEEPCAPS
:
935 if (arg2
> 1) /* Note, we rely on arg2 being unsigned here */
938 if (issecure(SECURE_KEEP_CAPS_LOCKED
))
941 new->securebits
|= issecure_mask(SECURE_KEEP_CAPS
);
943 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
947 /* No functionality available - continue with default */
952 /* Functionality provided */
954 return commit_creds(new);
963 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
964 * @mm: The VM space in which the new mapping is to be made
965 * @pages: The size of the mapping
967 * Determine whether the allocation of a new virtual mapping by the current
968 * task is permitted, returning 0 if permission is granted, -ve if not.
970 int cap_vm_enough_memory(struct mm_struct
*mm
, long pages
)
972 int cap_sys_admin
= 0;
974 if (cap_capable(current_cred(), &init_user_ns
, CAP_SYS_ADMIN
,
975 SECURITY_CAP_NOAUDIT
) == 0)
977 return __vm_enough_memory(mm
, pages
, cap_sys_admin
);
981 * cap_mmap_addr - check if able to map given addr
982 * @addr: address attempting to be mapped
984 * If the process is attempting to map memory below dac_mmap_min_addr they need
985 * CAP_SYS_RAWIO. The other parameters to this function are unused by the
986 * capability security module. Returns 0 if this mapping should be allowed
989 int cap_mmap_addr(unsigned long addr
)
993 if (addr
< dac_mmap_min_addr
) {
994 ret
= cap_capable(current_cred(), &init_user_ns
, CAP_SYS_RAWIO
,
996 /* set PF_SUPERPRIV if it turns out we allow the low mmap */
998 current
->flags
|= PF_SUPERPRIV
;
1003 int cap_mmap_file(struct file
*file
, unsigned long reqprot
,
1004 unsigned long prot
, unsigned long flags
)