7f0b2a68717d6fd8d57837308dfe219848c8e30d
1 /* Common capabilities, needed by capability.o and root_plug.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>
31 int cap_netlink_send(struct sock
*sk
, struct sk_buff
*skb
)
33 NETLINK_CB(skb
).eff_cap
= current_cap();
37 int cap_netlink_recv(struct sk_buff
*skb
, int cap
)
39 if (!cap_raised(NETLINK_CB(skb
).eff_cap
, cap
))
43 EXPORT_SYMBOL(cap_netlink_recv
);
46 * cap_capable - Determine whether current has a particular effective capability
47 * @cap: The capability to check for
48 * @audit: Whether to write an audit message or not
50 * Determine whether the nominated task has the specified capability amongst
51 * its effective set, returning 0 if it does, -ve if it does not. Note that
52 * this uses current's subjective/effective credentials.
54 * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
55 * function. That is, it has the reverse semantics: cap_capable() returns 0
56 * when a task has a capability, but the kernel's capable() returns 1 for this
59 int cap_capable(int cap
, int audit
)
61 return cap_raised(current_cap(), cap
) ? 0 : -EPERM
;
65 * cap_has_capability - Determine whether a task has a particular effective capability
66 * @tsk: The task to query
67 * @cred: The credentials to use
68 * @cap: The capability to check for
69 * @audit: Whether to write an audit message or not
71 * Determine whether the nominated task has the specified capability amongst
72 * its effective set, returning 0 if it does, -ve if it does not. Note that
73 * this uses the task's objective/real credentials.
75 * NOTE WELL: cap_has_capability() cannot be used like the kernel's
76 * has_capability() function. That is, it has the reverse semantics:
77 * cap_has_capability() returns 0 when a task has a capability, but the
78 * kernel's has_capability() returns 1 for this case.
80 int cap_task_capable(struct task_struct
*tsk
, const struct cred
*cred
, int cap
,
83 return cap_raised(cred
->cap_effective
, cap
) ? 0 : -EPERM
;
87 * cap_settime - Determine whether the current process may set the system clock
88 * @ts: The time to set
89 * @tz: The timezone to set
91 * Determine whether the current process may set the system clock and timezone
92 * information, returning 0 if permission granted, -ve if denied.
94 int cap_settime(struct timespec
*ts
, struct timezone
*tz
)
96 if (!capable(CAP_SYS_TIME
))
102 * cap_ptrace_may_access - Determine whether the current process may access
104 * @child: The process to be accessed
105 * @mode: The mode of attachment.
107 * Determine whether a process may access another, returning 0 if permission
108 * granted, -ve if denied.
110 int cap_ptrace_may_access(struct task_struct
*child
, unsigned int mode
)
115 if (!cap_issubset(__task_cred(child
)->cap_permitted
,
116 current_cred()->cap_permitted
) &&
117 !capable(CAP_SYS_PTRACE
))
124 * cap_ptrace_traceme - Determine whether another process may trace the current
125 * @parent: The task proposed to be the tracer
127 * Determine whether the nominated task is permitted to trace the current
128 * process, returning 0 if permission is granted, -ve if denied.
130 int cap_ptrace_traceme(struct task_struct
*parent
)
135 if (!cap_issubset(current_cred()->cap_permitted
,
136 __task_cred(parent
)->cap_permitted
) &&
137 !has_capability(parent
, CAP_SYS_PTRACE
))
144 * cap_capget - Retrieve a task's capability sets
145 * @target: The task from which to retrieve the capability sets
146 * @effective: The place to record the effective set
147 * @inheritable: The place to record the inheritable set
148 * @permitted: The place to record the permitted set
150 * This function retrieves the capabilities of the nominated task and returns
151 * them to the caller.
153 int cap_capget(struct task_struct
*target
, kernel_cap_t
*effective
,
154 kernel_cap_t
*inheritable
, kernel_cap_t
*permitted
)
156 const struct cred
*cred
;
158 /* Derived from kernel/capability.c:sys_capget. */
160 cred
= __task_cred(target
);
161 *effective
= cred
->cap_effective
;
162 *inheritable
= cred
->cap_inheritable
;
163 *permitted
= cred
->cap_permitted
;
169 * Determine whether the inheritable capabilities are limited to the old
170 * permitted set. Returns 1 if they are limited, 0 if they are not.
172 static inline int cap_inh_is_capped(void)
174 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
176 /* they are so limited unless the current task has the CAP_SETPCAP
179 if (cap_capable(CAP_SETPCAP
, SECURITY_CAP_AUDIT
) == 0)
186 * cap_capset - Validate and apply proposed changes to current's capabilities
187 * @new: The proposed new credentials; alterations should be made here
188 * @old: The current task's current credentials
189 * @effective: A pointer to the proposed new effective capabilities set
190 * @inheritable: A pointer to the proposed new inheritable capabilities set
191 * @permitted: A pointer to the proposed new permitted capabilities set
193 * This function validates and applies a proposed mass change to the current
194 * process's capability sets. The changes are made to the proposed new
195 * credentials, and assuming no error, will be committed by the caller of LSM.
197 int cap_capset(struct cred
*new,
198 const struct cred
*old
,
199 const kernel_cap_t
*effective
,
200 const kernel_cap_t
*inheritable
,
201 const kernel_cap_t
*permitted
)
203 if (cap_inh_is_capped() &&
204 !cap_issubset(*inheritable
,
205 cap_combine(old
->cap_inheritable
,
206 old
->cap_permitted
)))
207 /* incapable of using this inheritable set */
210 if (!cap_issubset(*inheritable
,
211 cap_combine(old
->cap_inheritable
,
213 /* no new pI capabilities outside bounding set */
216 /* verify restrictions on target's new Permitted set */
217 if (!cap_issubset(*permitted
, old
->cap_permitted
))
220 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
221 if (!cap_issubset(*effective
, *permitted
))
224 new->cap_effective
= *effective
;
225 new->cap_inheritable
= *inheritable
;
226 new->cap_permitted
= *permitted
;
231 * Clear proposed capability sets for execve().
233 static inline void bprm_clear_caps(struct linux_binprm
*bprm
)
235 cap_clear(bprm
->cred
->cap_permitted
);
236 bprm
->cap_effective
= false;
239 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
242 * cap_inode_need_killpriv - Determine if inode change affects privileges
243 * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
245 * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
246 * affects the security markings on that inode, and if it is, should
247 * inode_killpriv() be invoked or the change rejected?
249 * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
250 * -ve to deny the change.
252 int cap_inode_need_killpriv(struct dentry
*dentry
)
254 struct inode
*inode
= dentry
->d_inode
;
257 if (!inode
->i_op
|| !inode
->i_op
->getxattr
)
260 error
= inode
->i_op
->getxattr(dentry
, XATTR_NAME_CAPS
, NULL
, 0);
267 * cap_inode_killpriv - Erase the security markings on an inode
268 * @dentry: The inode/dentry to alter
270 * Erase the privilege-enhancing security markings on an inode.
272 * Returns 0 if successful, -ve on error.
274 int cap_inode_killpriv(struct dentry
*dentry
)
276 struct inode
*inode
= dentry
->d_inode
;
278 if (!inode
->i_op
|| !inode
->i_op
->removexattr
)
281 return inode
->i_op
->removexattr(dentry
, XATTR_NAME_CAPS
);
285 * Calculate the new process capability sets from the capability sets attached
288 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data
*caps
,
289 struct linux_binprm
*bprm
,
292 struct cred
*new = bprm
->cred
;
296 if (caps
->magic_etc
& VFS_CAP_FLAGS_EFFECTIVE
)
299 CAP_FOR_EACH_U32(i
) {
300 __u32 permitted
= caps
->permitted
.cap
[i
];
301 __u32 inheritable
= caps
->inheritable
.cap
[i
];
304 * pP' = (X & fP) | (pI & fI)
306 new->cap_permitted
.cap
[i
] =
307 (new->cap_bset
.cap
[i
] & permitted
) |
308 (new->cap_inheritable
.cap
[i
] & inheritable
);
310 if (permitted
& ~new->cap_permitted
.cap
[i
])
311 /* insufficient to execute correctly */
316 * For legacy apps, with no internal support for recognizing they
317 * do not have enough capabilities, we return an error if they are
318 * missing some "forced" (aka file-permitted) capabilities.
320 return *effective
? ret
: 0;
324 * Extract the on-exec-apply capability sets for an executable file.
326 int get_vfs_caps_from_disk(const struct dentry
*dentry
, struct cpu_vfs_cap_data
*cpu_caps
)
328 struct inode
*inode
= dentry
->d_inode
;
332 struct vfs_cap_data caps
;
334 memset(cpu_caps
, 0, sizeof(struct cpu_vfs_cap_data
));
336 if (!inode
|| !inode
->i_op
|| !inode
->i_op
->getxattr
)
339 size
= inode
->i_op
->getxattr((struct dentry
*)dentry
, XATTR_NAME_CAPS
, &caps
,
341 if (size
== -ENODATA
|| size
== -EOPNOTSUPP
)
342 /* no data, that's ok */
347 if (size
< sizeof(magic_etc
))
350 cpu_caps
->magic_etc
= magic_etc
= le32_to_cpu(caps
.magic_etc
);
352 switch (magic_etc
& VFS_CAP_REVISION_MASK
) {
353 case VFS_CAP_REVISION_1
:
354 if (size
!= XATTR_CAPS_SZ_1
)
356 tocopy
= VFS_CAP_U32_1
;
358 case VFS_CAP_REVISION_2
:
359 if (size
!= XATTR_CAPS_SZ_2
)
361 tocopy
= VFS_CAP_U32_2
;
367 CAP_FOR_EACH_U32(i
) {
370 cpu_caps
->permitted
.cap
[i
] = le32_to_cpu(caps
.data
[i
].permitted
);
371 cpu_caps
->inheritable
.cap
[i
] = le32_to_cpu(caps
.data
[i
].inheritable
);
378 * Attempt to get the on-exec apply capability sets for an executable file from
379 * its xattrs and, if present, apply them to the proposed credentials being
380 * constructed by execve().
382 static int get_file_caps(struct linux_binprm
*bprm
, bool *effective
)
384 struct dentry
*dentry
;
386 struct cpu_vfs_cap_data vcaps
;
388 bprm_clear_caps(bprm
);
390 if (!file_caps_enabled
)
393 if (bprm
->file
->f_vfsmnt
->mnt_flags
& MNT_NOSUID
)
396 dentry
= dget(bprm
->file
->f_dentry
);
398 rc
= get_vfs_caps_from_disk(dentry
, &vcaps
);
401 printk(KERN_NOTICE
"%s: get_vfs_caps_from_disk returned %d for %s\n",
402 __func__
, rc
, bprm
->filename
);
403 else if (rc
== -ENODATA
)
408 rc
= bprm_caps_from_vfs_caps(&vcaps
, bprm
, effective
);
410 printk(KERN_NOTICE
"%s: cap_from_disk returned %d for %s\n",
411 __func__
, rc
, bprm
->filename
);
416 bprm_clear_caps(bprm
);
422 int cap_inode_need_killpriv(struct dentry
*dentry
)
427 int cap_inode_killpriv(struct dentry
*dentry
)
432 int get_vfs_caps_from_disk(const struct dentry
*dentry
, struct cpu_vfs_cap_data
*cpu_caps
)
434 memset(cpu_caps
, 0, sizeof(struct cpu_vfs_cap_data
));
438 static inline int get_file_caps(struct linux_binprm
*bprm
, bool *effective
)
440 bprm_clear_caps(bprm
);
446 * Determine whether a exec'ing process's new permitted capabilities should be
447 * limited to just what it already has.
449 * This prevents processes that are being ptraced from gaining access to
450 * CAP_SETPCAP, unless the process they're tracing already has it, and the
451 * binary they're executing has filecaps that elevate it.
453 * Returns 1 if they should be limited, 0 if they are not.
455 static inline int cap_limit_ptraced_target(void)
457 #ifndef CONFIG_SECURITY_FILE_CAPABILITIES
458 if (capable(CAP_SETPCAP
))
465 * cap_bprm_set_creds - Set up the proposed credentials for execve().
466 * @bprm: The execution parameters, including the proposed creds
468 * Set up the proposed credentials for a new execution context being
469 * constructed by execve(). The proposed creds in @bprm->cred is altered,
470 * which won't take effect immediately. Returns 0 if successful, -ve on error.
472 int cap_bprm_set_creds(struct linux_binprm
*bprm
)
474 const struct cred
*old
= current_cred();
475 struct cred
*new = bprm
->cred
;
480 ret
= get_file_caps(bprm
, &effective
);
484 if (!issecure(SECURE_NOROOT
)) {
486 * To support inheritance of root-permissions and suid-root
487 * executables under compatibility mode, we override the
488 * capability sets for the file.
490 * If only the real uid is 0, we do not set the effective bit.
492 if (new->euid
== 0 || new->uid
== 0) {
493 /* pP' = (cap_bset & ~0) | (pI & ~0) */
494 new->cap_permitted
= cap_combine(old
->cap_bset
,
495 old
->cap_inheritable
);
501 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
502 * credentials unless they have the appropriate permit
504 if ((new->euid
!= old
->uid
||
505 new->egid
!= old
->gid
||
506 !cap_issubset(new->cap_permitted
, old
->cap_permitted
)) &&
507 bprm
->unsafe
& ~LSM_UNSAFE_PTRACE_CAP
) {
508 /* downgrade; they get no more than they had, and maybe less */
509 if (!capable(CAP_SETUID
)) {
510 new->euid
= new->uid
;
511 new->egid
= new->gid
;
513 if (cap_limit_ptraced_target())
514 new->cap_permitted
= cap_intersect(new->cap_permitted
,
518 new->suid
= new->fsuid
= new->euid
;
519 new->sgid
= new->fsgid
= new->egid
;
521 /* For init, we want to retain the capabilities set in the initial
522 * task. Thus we skip the usual capability rules
524 if (!is_global_init(current
)) {
526 new->cap_effective
= new->cap_permitted
;
528 cap_clear(new->cap_effective
);
530 bprm
->cap_effective
= effective
;
533 * Audit candidate if current->cap_effective is set
535 * We do not bother to audit if 3 things are true:
536 * 1) cap_effective has all caps
538 * 3) root is supposed to have all caps (SECURE_NOROOT)
539 * Since this is just a normal root execing a process.
541 * Number 1 above might fail if you don't have a full bset, but I think
542 * that is interesting information to audit.
544 if (!cap_isclear(new->cap_effective
)) {
545 if (!cap_issubset(CAP_FULL_SET
, new->cap_effective
) ||
546 new->euid
!= 0 || new->uid
!= 0 ||
547 issecure(SECURE_NOROOT
)) {
548 ret
= audit_log_bprm_fcaps(bprm
, new, old
);
554 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
559 * cap_bprm_secureexec - Determine whether a secure execution is required
560 * @bprm: The execution parameters
562 * Determine whether a secure execution is required, return 1 if it is, and 0
565 * The credentials have been committed by this point, and so are no longer
566 * available through @bprm->cred.
568 int cap_bprm_secureexec(struct linux_binprm
*bprm
)
570 const struct cred
*cred
= current_cred();
572 if (cred
->uid
!= 0) {
573 if (bprm
->cap_effective
)
575 if (!cap_isclear(cred
->cap_permitted
))
579 return (cred
->euid
!= cred
->uid
||
580 cred
->egid
!= cred
->gid
);
584 * cap_inode_setxattr - Determine whether an xattr may be altered
585 * @dentry: The inode/dentry being altered
586 * @name: The name of the xattr to be changed
587 * @value: The value that the xattr will be changed to
588 * @size: The size of value
589 * @flags: The replacement flag
591 * Determine whether an xattr may be altered or set on an inode, returning 0 if
592 * permission is granted, -ve if denied.
594 * This is used to make sure security xattrs don't get updated or set by those
595 * who aren't privileged to do so.
597 int cap_inode_setxattr(struct dentry
*dentry
, const char *name
,
598 const void *value
, size_t size
, int flags
)
600 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
601 if (!capable(CAP_SETFCAP
))
606 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
607 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
608 !capable(CAP_SYS_ADMIN
))
614 * cap_inode_removexattr - Determine whether an xattr may be removed
615 * @dentry: The inode/dentry being altered
616 * @name: The name of the xattr to be changed
618 * Determine whether an xattr may be removed from an inode, returning 0 if
619 * permission is granted, -ve if denied.
621 * This is used to make sure security xattrs don't get removed by those who
622 * aren't privileged to remove them.
624 int cap_inode_removexattr(struct dentry
*dentry
, const char *name
)
626 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
627 if (!capable(CAP_SETFCAP
))
632 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
633 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
634 !capable(CAP_SYS_ADMIN
))
640 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
641 * a process after a call to setuid, setreuid, or setresuid.
643 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
644 * {r,e,s}uid != 0, the permitted and effective capabilities are
647 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
648 * capabilities of the process are cleared.
650 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
651 * capabilities are set to the permitted capabilities.
653 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
658 * cevans - New behaviour, Oct '99
659 * A process may, via prctl(), elect to keep its capabilities when it
660 * calls setuid() and switches away from uid==0. Both permitted and
661 * effective sets will be retained.
662 * Without this change, it was impossible for a daemon to drop only some
663 * of its privilege. The call to setuid(!=0) would drop all privileges!
664 * Keeping uid 0 is not an option because uid 0 owns too many vital
666 * Thanks to Olaf Kirch and Peter Benie for spotting this.
668 static inline void cap_emulate_setxuid(struct cred
*new, const struct cred
*old
)
670 if ((old
->uid
== 0 || old
->euid
== 0 || old
->suid
== 0) &&
671 (new->uid
!= 0 && new->euid
!= 0 && new->suid
!= 0) &&
672 !issecure(SECURE_KEEP_CAPS
)) {
673 cap_clear(new->cap_permitted
);
674 cap_clear(new->cap_effective
);
676 if (old
->euid
== 0 && new->euid
!= 0)
677 cap_clear(new->cap_effective
);
678 if (old
->euid
!= 0 && new->euid
== 0)
679 new->cap_effective
= new->cap_permitted
;
683 * cap_task_fix_setuid - Fix up the results of setuid() call
684 * @new: The proposed credentials
685 * @old: The current task's current credentials
686 * @flags: Indications of what has changed
688 * Fix up the results of setuid() call before the credential changes are
689 * actually applied, returning 0 to grant the changes, -ve to deny them.
691 int cap_task_fix_setuid(struct cred
*new, const struct cred
*old
, int flags
)
697 /* juggle the capabilities to follow [RES]UID changes unless
698 * otherwise suppressed */
699 if (!issecure(SECURE_NO_SETUID_FIXUP
))
700 cap_emulate_setxuid(new, old
);
704 /* juggle the capabilties to follow FSUID changes, unless
705 * otherwise suppressed
707 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
708 * if not, we might be a bit too harsh here.
710 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
711 if (old
->fsuid
== 0 && new->fsuid
!= 0)
713 cap_drop_fs_set(new->cap_effective
);
715 if (old
->fsuid
!= 0 && new->fsuid
== 0)
717 cap_raise_fs_set(new->cap_effective
,
729 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
731 * Rationale: code calling task_setscheduler, task_setioprio, and
732 * task_setnice, assumes that
733 * . if capable(cap_sys_nice), then those actions should be allowed
734 * . if not capable(cap_sys_nice), but acting on your own processes,
735 * then those actions should be allowed
736 * This is insufficient now since you can call code without suid, but
737 * yet with increased caps.
738 * So we check for increased caps on the target process.
740 static int cap_safe_nice(struct task_struct
*p
)
745 is_subset
= cap_issubset(__task_cred(p
)->cap_permitted
,
746 current_cred()->cap_permitted
);
749 if (!is_subset
&& !capable(CAP_SYS_NICE
))
755 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
756 * @p: The task to affect
757 * @policy: The policy to effect
758 * @lp: The parameters to the scheduling policy
760 * Detemine if the requested scheduler policy change is permitted for the
761 * specified task, returning 0 if permission is granted, -ve if denied.
763 int cap_task_setscheduler(struct task_struct
*p
, int policy
,
764 struct sched_param
*lp
)
766 return cap_safe_nice(p
);
770 * cap_task_ioprio - Detemine if I/O priority change is permitted
771 * @p: The task to affect
772 * @ioprio: The I/O priority to set
774 * Detemine if the requested I/O priority change is permitted for the specified
775 * task, returning 0 if permission is granted, -ve if denied.
777 int cap_task_setioprio(struct task_struct
*p
, int ioprio
)
779 return cap_safe_nice(p
);
783 * cap_task_ioprio - Detemine if task priority change is permitted
784 * @p: The task to affect
785 * @nice: The nice value to set
787 * Detemine if the requested task priority change is permitted for the
788 * specified task, returning 0 if permission is granted, -ve if denied.
790 int cap_task_setnice(struct task_struct
*p
, int nice
)
792 return cap_safe_nice(p
);
796 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
797 * the current task's bounding set. Returns 0 on success, -ve on error.
799 static long cap_prctl_drop(struct cred
*new, unsigned long cap
)
801 if (!capable(CAP_SETPCAP
))
806 cap_lower(new->cap_bset
, cap
);
811 int cap_task_setscheduler (struct task_struct
*p
, int policy
,
812 struct sched_param
*lp
)
816 int cap_task_setioprio (struct task_struct
*p
, int ioprio
)
820 int cap_task_setnice (struct task_struct
*p
, int nice
)
827 * cap_task_prctl - Implement process control functions for this security module
828 * @option: The process control function requested
829 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
831 * Allow process control functions (sys_prctl()) to alter capabilities; may
832 * also deny access to other functions not otherwise implemented here.
834 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
835 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
836 * modules will consider performing the function.
838 int cap_task_prctl(int option
, unsigned long arg2
, unsigned long arg3
,
839 unsigned long arg4
, unsigned long arg5
)
844 new = prepare_creds();
849 case PR_CAPBSET_READ
:
851 if (!cap_valid(arg2
))
853 error
= !!cap_raised(new->cap_bset
, arg2
);
856 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
857 case PR_CAPBSET_DROP
:
858 error
= cap_prctl_drop(new, arg2
);
864 * The next four prctl's remain to assist with transitioning a
865 * system from legacy UID=0 based privilege (when filesystem
866 * capabilities are not in use) to a system using filesystem
867 * capabilities only - as the POSIX.1e draft intended.
871 * PR_SET_SECUREBITS =
872 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
873 * | issecure_mask(SECURE_NOROOT)
874 * | issecure_mask(SECURE_NOROOT_LOCKED)
875 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
876 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
878 * will ensure that the current process and all of its
879 * children will be locked into a pure
880 * capability-based-privilege environment.
882 case PR_SET_SECUREBITS
:
884 if ((((new->securebits
& SECURE_ALL_LOCKS
) >> 1)
885 & (new->securebits
^ arg2
)) /*[1]*/
886 || ((new->securebits
& SECURE_ALL_LOCKS
& ~arg2
)) /*[2]*/
887 || (arg2
& ~(SECURE_ALL_LOCKS
| SECURE_ALL_BITS
)) /*[3]*/
888 || (cap_capable(CAP_SETPCAP
, SECURITY_CAP_AUDIT
) != 0) /*[4]*/
890 * [1] no changing of bits that are locked
891 * [2] no unlocking of locks
892 * [3] no setting of unsupported bits
893 * [4] doing anything requires privilege (go read about
894 * the "sendmail capabilities bug")
897 /* cannot change a locked bit */
899 new->securebits
= arg2
;
902 case PR_GET_SECUREBITS
:
903 error
= new->securebits
;
906 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
908 case PR_GET_KEEPCAPS
:
909 if (issecure(SECURE_KEEP_CAPS
))
913 case PR_SET_KEEPCAPS
:
915 if (arg2
> 1) /* Note, we rely on arg2 being unsigned here */
918 if (issecure(SECURE_KEEP_CAPS_LOCKED
))
921 new->securebits
|= issecure_mask(SECURE_KEEP_CAPS
);
923 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
927 /* No functionality available - continue with default */
932 /* Functionality provided */
934 return commit_creds(new);
944 * cap_syslog - Determine whether syslog function is permitted
945 * @type: Function requested
947 * Determine whether the current process is permitted to use a particular
948 * syslog function, returning 0 if permission is granted, -ve if not.
950 int cap_syslog(int type
)
952 if ((type
!= 3 && type
!= 10) && !capable(CAP_SYS_ADMIN
))
958 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
959 * @mm: The VM space in which the new mapping is to be made
960 * @pages: The size of the mapping
962 * Determine whether the allocation of a new virtual mapping by the current
963 * task is permitted, returning 0 if permission is granted, -ve if not.
965 int cap_vm_enough_memory(struct mm_struct
*mm
, long pages
)
967 int cap_sys_admin
= 0;
969 if (cap_capable(CAP_SYS_ADMIN
, SECURITY_CAP_NOAUDIT
) == 0)
971 return __vm_enough_memory(mm
, pages
, cap_sys_admin
);
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