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
,
80 /* The creator of the user namespace has all caps. */
81 if (targ_ns
!= &init_user_ns
&& targ_ns
->creator
== cred
->user
)
84 /* Do we have the necessary capabilities? */
85 if (targ_ns
== cred
->user
->user_ns
)
86 return cap_raised(cred
->cap_effective
, cap
) ? 0 : -EPERM
;
88 /* Have we tried all of the parent namespaces? */
89 if (targ_ns
== &init_user_ns
)
93 *If you have a capability in a parent user ns, then you have
94 * it over all children user namespaces as well.
96 targ_ns
= targ_ns
->creator
->user_ns
;
99 /* We never get here */
103 * cap_settime - Determine whether the current process may set the system clock
104 * @ts: The time to set
105 * @tz: The timezone to set
107 * Determine whether the current process may set the system clock and timezone
108 * information, returning 0 if permission granted, -ve if denied.
110 int cap_settime(const struct timespec
*ts
, const struct timezone
*tz
)
112 if (!capable(CAP_SYS_TIME
))
118 * cap_ptrace_access_check - Determine whether the current process may access
120 * @child: The process to be accessed
121 * @mode: The mode of attachment.
123 * If we are in the same or an ancestor user_ns and have all the target
124 * task's capabilities, then ptrace access is allowed.
125 * If we have the ptrace capability to the target user_ns, then ptrace
129 * Determine whether a process may access another, returning 0 if permission
130 * granted, -ve if denied.
132 int cap_ptrace_access_check(struct task_struct
*child
, unsigned int mode
)
135 const struct cred
*cred
, *child_cred
;
138 cred
= current_cred();
139 child_cred
= __task_cred(child
);
140 if (cred
->user
->user_ns
== child_cred
->user
->user_ns
&&
141 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
143 if (ns_capable(child_cred
->user
->user_ns
, CAP_SYS_PTRACE
))
152 * cap_ptrace_traceme - Determine whether another process may trace the current
153 * @parent: The task proposed to be the tracer
155 * If parent is in the same or an ancestor user_ns and has all current's
156 * capabilities, then ptrace access is allowed.
157 * If parent has the ptrace capability to current's user_ns, then ptrace
161 * Determine whether the nominated task is permitted to trace the current
162 * process, returning 0 if permission is granted, -ve if denied.
164 int cap_ptrace_traceme(struct task_struct
*parent
)
167 const struct cred
*cred
, *child_cred
;
170 cred
= __task_cred(parent
);
171 child_cred
= current_cred();
172 if (cred
->user
->user_ns
== child_cred
->user
->user_ns
&&
173 cap_issubset(child_cred
->cap_permitted
, cred
->cap_permitted
))
175 if (has_ns_capability(parent
, child_cred
->user
->user_ns
, CAP_SYS_PTRACE
))
184 * cap_capget - Retrieve a task's capability sets
185 * @target: The task from which to retrieve the capability sets
186 * @effective: The place to record the effective set
187 * @inheritable: The place to record the inheritable set
188 * @permitted: The place to record the permitted set
190 * This function retrieves the capabilities of the nominated task and returns
191 * them to the caller.
193 int cap_capget(struct task_struct
*target
, kernel_cap_t
*effective
,
194 kernel_cap_t
*inheritable
, kernel_cap_t
*permitted
)
196 const struct cred
*cred
;
198 /* Derived from kernel/capability.c:sys_capget. */
200 cred
= __task_cred(target
);
201 *effective
= cred
->cap_effective
;
202 *inheritable
= cred
->cap_inheritable
;
203 *permitted
= cred
->cap_permitted
;
209 * Determine whether the inheritable capabilities are limited to the old
210 * permitted set. Returns 1 if they are limited, 0 if they are not.
212 static inline int cap_inh_is_capped(void)
215 /* they are so limited unless the current task has the CAP_SETPCAP
218 if (cap_capable(current_cred(), current_cred()->user
->user_ns
,
219 CAP_SETPCAP
, SECURITY_CAP_AUDIT
) == 0)
225 * cap_capset - Validate and apply proposed changes to current's capabilities
226 * @new: The proposed new credentials; alterations should be made here
227 * @old: The current task's current credentials
228 * @effective: A pointer to the proposed new effective capabilities set
229 * @inheritable: A pointer to the proposed new inheritable capabilities set
230 * @permitted: A pointer to the proposed new permitted capabilities set
232 * This function validates and applies a proposed mass change to the current
233 * process's capability sets. The changes are made to the proposed new
234 * credentials, and assuming no error, will be committed by the caller of LSM.
236 int cap_capset(struct cred
*new,
237 const struct cred
*old
,
238 const kernel_cap_t
*effective
,
239 const kernel_cap_t
*inheritable
,
240 const kernel_cap_t
*permitted
)
242 if (cap_inh_is_capped() &&
243 !cap_issubset(*inheritable
,
244 cap_combine(old
->cap_inheritable
,
245 old
->cap_permitted
)))
246 /* incapable of using this inheritable set */
249 if (!cap_issubset(*inheritable
,
250 cap_combine(old
->cap_inheritable
,
252 /* no new pI capabilities outside bounding set */
255 /* verify restrictions on target's new Permitted set */
256 if (!cap_issubset(*permitted
, old
->cap_permitted
))
259 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
260 if (!cap_issubset(*effective
, *permitted
))
263 new->cap_effective
= *effective
;
264 new->cap_inheritable
= *inheritable
;
265 new->cap_permitted
= *permitted
;
270 * Clear proposed capability sets for execve().
272 static inline void bprm_clear_caps(struct linux_binprm
*bprm
)
274 cap_clear(bprm
->cred
->cap_permitted
);
275 bprm
->cap_effective
= false;
279 * cap_inode_need_killpriv - Determine if inode change affects privileges
280 * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
282 * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
283 * affects the security markings on that inode, and if it is, should
284 * inode_killpriv() be invoked or the change rejected?
286 * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
287 * -ve to deny the change.
289 int cap_inode_need_killpriv(struct dentry
*dentry
)
291 struct inode
*inode
= dentry
->d_inode
;
294 if (!inode
->i_op
->getxattr
)
297 error
= inode
->i_op
->getxattr(dentry
, XATTR_NAME_CAPS
, NULL
, 0);
304 * cap_inode_killpriv - Erase the security markings on an inode
305 * @dentry: The inode/dentry to alter
307 * Erase the privilege-enhancing security markings on an inode.
309 * Returns 0 if successful, -ve on error.
311 int cap_inode_killpriv(struct dentry
*dentry
)
313 struct inode
*inode
= dentry
->d_inode
;
315 if (!inode
->i_op
->removexattr
)
318 return inode
->i_op
->removexattr(dentry
, XATTR_NAME_CAPS
);
322 * Calculate the new process capability sets from the capability sets attached
325 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data
*caps
,
326 struct linux_binprm
*bprm
,
330 struct cred
*new = bprm
->cred
;
334 if (caps
->magic_etc
& VFS_CAP_FLAGS_EFFECTIVE
)
337 if (caps
->magic_etc
& VFS_CAP_REVISION_MASK
)
340 CAP_FOR_EACH_U32(i
) {
341 __u32 permitted
= caps
->permitted
.cap
[i
];
342 __u32 inheritable
= caps
->inheritable
.cap
[i
];
345 * pP' = (X & fP) | (pI & fI)
347 new->cap_permitted
.cap
[i
] =
348 (new->cap_bset
.cap
[i
] & permitted
) |
349 (new->cap_inheritable
.cap
[i
] & inheritable
);
351 if (permitted
& ~new->cap_permitted
.cap
[i
])
352 /* insufficient to execute correctly */
357 * For legacy apps, with no internal support for recognizing they
358 * do not have enough capabilities, we return an error if they are
359 * missing some "forced" (aka file-permitted) capabilities.
361 return *effective
? ret
: 0;
365 * Extract the on-exec-apply capability sets for an executable file.
367 int get_vfs_caps_from_disk(const struct dentry
*dentry
, struct cpu_vfs_cap_data
*cpu_caps
)
369 struct inode
*inode
= dentry
->d_inode
;
373 struct vfs_cap_data caps
;
375 memset(cpu_caps
, 0, sizeof(struct cpu_vfs_cap_data
));
377 if (!inode
|| !inode
->i_op
->getxattr
)
380 size
= inode
->i_op
->getxattr((struct dentry
*)dentry
, XATTR_NAME_CAPS
, &caps
,
382 if (size
== -ENODATA
|| size
== -EOPNOTSUPP
)
383 /* no data, that's ok */
388 if (size
< sizeof(magic_etc
))
391 cpu_caps
->magic_etc
= magic_etc
= le32_to_cpu(caps
.magic_etc
);
393 switch (magic_etc
& VFS_CAP_REVISION_MASK
) {
394 case VFS_CAP_REVISION_1
:
395 if (size
!= XATTR_CAPS_SZ_1
)
397 tocopy
= VFS_CAP_U32_1
;
399 case VFS_CAP_REVISION_2
:
400 if (size
!= XATTR_CAPS_SZ_2
)
402 tocopy
= VFS_CAP_U32_2
;
408 CAP_FOR_EACH_U32(i
) {
411 cpu_caps
->permitted
.cap
[i
] = le32_to_cpu(caps
.data
[i
].permitted
);
412 cpu_caps
->inheritable
.cap
[i
] = le32_to_cpu(caps
.data
[i
].inheritable
);
419 * Attempt to get the on-exec apply capability sets for an executable file from
420 * its xattrs and, if present, apply them to the proposed credentials being
421 * constructed by execve().
423 static int get_file_caps(struct linux_binprm
*bprm
, bool *effective
, bool *has_cap
)
425 struct dentry
*dentry
;
427 struct cpu_vfs_cap_data vcaps
;
429 bprm_clear_caps(bprm
);
431 if (!file_caps_enabled
)
434 if (bprm
->file
->f_vfsmnt
->mnt_flags
& MNT_NOSUID
)
437 dentry
= dget(bprm
->file
->f_dentry
);
439 rc
= get_vfs_caps_from_disk(dentry
, &vcaps
);
442 printk(KERN_NOTICE
"%s: get_vfs_caps_from_disk returned %d for %s\n",
443 __func__
, rc
, bprm
->filename
);
444 else if (rc
== -ENODATA
)
449 rc
= bprm_caps_from_vfs_caps(&vcaps
, bprm
, effective
, has_cap
);
451 printk(KERN_NOTICE
"%s: cap_from_disk returned %d for %s\n",
452 __func__
, rc
, bprm
->filename
);
457 bprm_clear_caps(bprm
);
463 * cap_bprm_set_creds - Set up the proposed credentials for execve().
464 * @bprm: The execution parameters, including the proposed creds
466 * Set up the proposed credentials for a new execution context being
467 * constructed by execve(). The proposed creds in @bprm->cred is altered,
468 * which won't take effect immediately. Returns 0 if successful, -ve on error.
470 int cap_bprm_set_creds(struct linux_binprm
*bprm
)
472 const struct cred
*old
= current_cred();
473 struct cred
*new = bprm
->cred
;
474 bool effective
, has_cap
= false;
478 ret
= get_file_caps(bprm
, &effective
, &has_cap
);
482 if (!issecure(SECURE_NOROOT
)) {
484 * If the legacy file capability is set, then don't set privs
485 * for a setuid root binary run by a non-root user. Do set it
486 * for a root user just to cause least surprise to an admin.
488 if (has_cap
&& new->uid
!= 0 && new->euid
== 0) {
489 warn_setuid_and_fcaps_mixed(bprm
->filename
);
493 * To support inheritance of root-permissions and suid-root
494 * executables under compatibility mode, we override the
495 * capability sets for the file.
497 * If only the real uid is 0, we do not set the effective bit.
499 if (new->euid
== 0 || new->uid
== 0) {
500 /* pP' = (cap_bset & ~0) | (pI & ~0) */
501 new->cap_permitted
= cap_combine(old
->cap_bset
,
502 old
->cap_inheritable
);
509 /* if we have fs caps, clear dangerous personality flags */
510 if (!cap_issubset(new->cap_permitted
, old
->cap_permitted
))
511 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
514 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
515 * credentials unless they have the appropriate permit
517 if ((new->euid
!= old
->uid
||
518 new->egid
!= old
->gid
||
519 !cap_issubset(new->cap_permitted
, old
->cap_permitted
)) &&
520 bprm
->unsafe
& ~LSM_UNSAFE_PTRACE_CAP
) {
521 /* downgrade; they get no more than they had, and maybe less */
522 if (!capable(CAP_SETUID
)) {
523 new->euid
= new->uid
;
524 new->egid
= new->gid
;
526 new->cap_permitted
= cap_intersect(new->cap_permitted
,
530 new->suid
= new->fsuid
= new->euid
;
531 new->sgid
= new->fsgid
= new->egid
;
534 new->cap_effective
= new->cap_permitted
;
536 cap_clear(new->cap_effective
);
537 bprm
->cap_effective
= effective
;
540 * Audit candidate if current->cap_effective is set
542 * We do not bother to audit if 3 things are true:
543 * 1) cap_effective has all caps
545 * 3) root is supposed to have all caps (SECURE_NOROOT)
546 * Since this is just a normal root execing a process.
548 * Number 1 above might fail if you don't have a full bset, but I think
549 * that is interesting information to audit.
551 if (!cap_isclear(new->cap_effective
)) {
552 if (!cap_issubset(CAP_FULL_SET
, new->cap_effective
) ||
553 new->euid
!= 0 || new->uid
!= 0 ||
554 issecure(SECURE_NOROOT
)) {
555 ret
= audit_log_bprm_fcaps(bprm
, new, old
);
561 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
566 * cap_bprm_secureexec - Determine whether a secure execution is required
567 * @bprm: The execution parameters
569 * Determine whether a secure execution is required, return 1 if it is, and 0
572 * The credentials have been committed by this point, and so are no longer
573 * available through @bprm->cred.
575 int cap_bprm_secureexec(struct linux_binprm
*bprm
)
577 const struct cred
*cred
= current_cred();
579 if (cred
->uid
!= 0) {
580 if (bprm
->cap_effective
)
582 if (!cap_isclear(cred
->cap_permitted
))
586 return (cred
->euid
!= cred
->uid
||
587 cred
->egid
!= cred
->gid
);
591 * cap_inode_setxattr - Determine whether an xattr may be altered
592 * @dentry: The inode/dentry being altered
593 * @name: The name of the xattr to be changed
594 * @value: The value that the xattr will be changed to
595 * @size: The size of value
596 * @flags: The replacement flag
598 * Determine whether an xattr may be altered or set on an inode, returning 0 if
599 * permission is granted, -ve if denied.
601 * This is used to make sure security xattrs don't get updated or set by those
602 * who aren't privileged to do so.
604 int cap_inode_setxattr(struct dentry
*dentry
, const char *name
,
605 const void *value
, size_t size
, int flags
)
607 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
608 if (!capable(CAP_SETFCAP
))
613 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
614 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
615 !capable(CAP_SYS_ADMIN
))
621 * cap_inode_removexattr - Determine whether an xattr may be removed
622 * @dentry: The inode/dentry being altered
623 * @name: The name of the xattr to be changed
625 * Determine whether an xattr may be removed from an inode, returning 0 if
626 * permission is granted, -ve if denied.
628 * This is used to make sure security xattrs don't get removed by those who
629 * aren't privileged to remove them.
631 int cap_inode_removexattr(struct dentry
*dentry
, const char *name
)
633 if (!strcmp(name
, XATTR_NAME_CAPS
)) {
634 if (!capable(CAP_SETFCAP
))
639 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
640 sizeof(XATTR_SECURITY_PREFIX
) - 1) &&
641 !capable(CAP_SYS_ADMIN
))
647 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
648 * a process after a call to setuid, setreuid, or setresuid.
650 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
651 * {r,e,s}uid != 0, the permitted and effective capabilities are
654 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
655 * capabilities of the process are cleared.
657 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
658 * capabilities are set to the permitted capabilities.
660 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
665 * cevans - New behaviour, Oct '99
666 * A process may, via prctl(), elect to keep its capabilities when it
667 * calls setuid() and switches away from uid==0. Both permitted and
668 * effective sets will be retained.
669 * Without this change, it was impossible for a daemon to drop only some
670 * of its privilege. The call to setuid(!=0) would drop all privileges!
671 * Keeping uid 0 is not an option because uid 0 owns too many vital
673 * Thanks to Olaf Kirch and Peter Benie for spotting this.
675 static inline void cap_emulate_setxuid(struct cred
*new, const struct cred
*old
)
677 if ((old
->uid
== 0 || old
->euid
== 0 || old
->suid
== 0) &&
678 (new->uid
!= 0 && new->euid
!= 0 && new->suid
!= 0) &&
679 !issecure(SECURE_KEEP_CAPS
)) {
680 cap_clear(new->cap_permitted
);
681 cap_clear(new->cap_effective
);
683 if (old
->euid
== 0 && new->euid
!= 0)
684 cap_clear(new->cap_effective
);
685 if (old
->euid
!= 0 && new->euid
== 0)
686 new->cap_effective
= new->cap_permitted
;
690 * cap_task_fix_setuid - Fix up the results of setuid() call
691 * @new: The proposed credentials
692 * @old: The current task's current credentials
693 * @flags: Indications of what has changed
695 * Fix up the results of setuid() call before the credential changes are
696 * actually applied, returning 0 to grant the changes, -ve to deny them.
698 int cap_task_fix_setuid(struct cred
*new, const struct cred
*old
, int flags
)
704 /* juggle the capabilities to follow [RES]UID changes unless
705 * otherwise suppressed */
706 if (!issecure(SECURE_NO_SETUID_FIXUP
))
707 cap_emulate_setxuid(new, old
);
711 /* juggle the capabilties to follow FSUID changes, unless
712 * otherwise suppressed
714 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
715 * if not, we might be a bit too harsh here.
717 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
718 if (old
->fsuid
== 0 && new->fsuid
!= 0)
720 cap_drop_fs_set(new->cap_effective
);
722 if (old
->fsuid
!= 0 && new->fsuid
== 0)
724 cap_raise_fs_set(new->cap_effective
,
737 * Rationale: code calling task_setscheduler, task_setioprio, and
738 * task_setnice, assumes that
739 * . if capable(cap_sys_nice), then those actions should be allowed
740 * . if not capable(cap_sys_nice), but acting on your own processes,
741 * then those actions should be allowed
742 * This is insufficient now since you can call code without suid, but
743 * yet with increased caps.
744 * So we check for increased caps on the target process.
746 static int cap_safe_nice(struct task_struct
*p
)
751 is_subset
= cap_issubset(__task_cred(p
)->cap_permitted
,
752 current_cred()->cap_permitted
);
755 if (!is_subset
&& !capable(CAP_SYS_NICE
))
761 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
762 * @p: The task to affect
764 * Detemine if the requested scheduler policy change is permitted for the
765 * specified task, returning 0 if permission is granted, -ve if denied.
767 int cap_task_setscheduler(struct task_struct
*p
)
769 return cap_safe_nice(p
);
773 * cap_task_ioprio - Detemine if I/O priority change is permitted
774 * @p: The task to affect
775 * @ioprio: The I/O priority to set
777 * Detemine if the requested I/O priority change is permitted for the specified
778 * task, returning 0 if permission is granted, -ve if denied.
780 int cap_task_setioprio(struct task_struct
*p
, int ioprio
)
782 return cap_safe_nice(p
);
786 * cap_task_ioprio - Detemine if task priority change is permitted
787 * @p: The task to affect
788 * @nice: The nice value to set
790 * Detemine if the requested task priority change is permitted for the
791 * specified task, returning 0 if permission is granted, -ve if denied.
793 int cap_task_setnice(struct task_struct
*p
, int nice
)
795 return cap_safe_nice(p
);
799 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
800 * the current task's bounding set. Returns 0 on success, -ve on error.
802 static long cap_prctl_drop(struct cred
*new, unsigned long cap
)
804 if (!capable(CAP_SETPCAP
))
809 cap_lower(new->cap_bset
, cap
);
814 * cap_task_prctl - Implement process control functions for this security module
815 * @option: The process control function requested
816 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
818 * Allow process control functions (sys_prctl()) to alter capabilities; may
819 * also deny access to other functions not otherwise implemented here.
821 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
822 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
823 * modules will consider performing the function.
825 int cap_task_prctl(int option
, unsigned long arg2
, unsigned long arg3
,
826 unsigned long arg4
, unsigned long arg5
)
831 new = prepare_creds();
836 case PR_CAPBSET_READ
:
838 if (!cap_valid(arg2
))
840 error
= !!cap_raised(new->cap_bset
, arg2
);
843 case PR_CAPBSET_DROP
:
844 error
= cap_prctl_drop(new, arg2
);
850 * The next four prctl's remain to assist with transitioning a
851 * system from legacy UID=0 based privilege (when filesystem
852 * capabilities are not in use) to a system using filesystem
853 * capabilities only - as the POSIX.1e draft intended.
857 * PR_SET_SECUREBITS =
858 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
859 * | issecure_mask(SECURE_NOROOT)
860 * | issecure_mask(SECURE_NOROOT_LOCKED)
861 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
862 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
864 * will ensure that the current process and all of its
865 * children will be locked into a pure
866 * capability-based-privilege environment.
868 case PR_SET_SECUREBITS
:
870 if ((((new->securebits
& SECURE_ALL_LOCKS
) >> 1)
871 & (new->securebits
^ arg2
)) /*[1]*/
872 || ((new->securebits
& SECURE_ALL_LOCKS
& ~arg2
)) /*[2]*/
873 || (arg2
& ~(SECURE_ALL_LOCKS
| SECURE_ALL_BITS
)) /*[3]*/
874 || (cap_capable(current_cred(),
875 current_cred()->user
->user_ns
, CAP_SETPCAP
,
876 SECURITY_CAP_AUDIT
) != 0) /*[4]*/
878 * [1] no changing of bits that are locked
879 * [2] no unlocking of locks
880 * [3] no setting of unsupported bits
881 * [4] doing anything requires privilege (go read about
882 * the "sendmail capabilities bug")
885 /* cannot change a locked bit */
887 new->securebits
= arg2
;
890 case PR_GET_SECUREBITS
:
891 error
= new->securebits
;
894 case PR_GET_KEEPCAPS
:
895 if (issecure(SECURE_KEEP_CAPS
))
899 case PR_SET_KEEPCAPS
:
901 if (arg2
> 1) /* Note, we rely on arg2 being unsigned here */
904 if (issecure(SECURE_KEEP_CAPS_LOCKED
))
907 new->securebits
|= issecure_mask(SECURE_KEEP_CAPS
);
909 new->securebits
&= ~issecure_mask(SECURE_KEEP_CAPS
);
913 /* No functionality available - continue with default */
918 /* Functionality provided */
920 return commit_creds(new);
929 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
930 * @mm: The VM space in which the new mapping is to be made
931 * @pages: The size of the mapping
933 * Determine whether the allocation of a new virtual mapping by the current
934 * task is permitted, returning 0 if permission is granted, -ve if not.
936 int cap_vm_enough_memory(struct mm_struct
*mm
, long pages
)
938 int cap_sys_admin
= 0;
940 if (cap_capable(current_cred(), &init_user_ns
, CAP_SYS_ADMIN
,
941 SECURITY_CAP_NOAUDIT
) == 0)
943 return __vm_enough_memory(mm
, pages
, cap_sys_admin
);
947 * cap_file_mmap - check if able to map given addr
952 * @addr: address attempting to be mapped
955 * If the process is attempting to map memory below dac_mmap_min_addr they need
956 * CAP_SYS_RAWIO. The other parameters to this function are unused by the
957 * capability security module. Returns 0 if this mapping should be allowed
960 int cap_file_mmap(struct file
*file
, unsigned long reqprot
,
961 unsigned long prot
, unsigned long flags
,
962 unsigned long addr
, unsigned long addr_only
)
966 if (addr
< dac_mmap_min_addr
) {
967 ret
= cap_capable(current_cred(), &init_user_ns
, CAP_SYS_RAWIO
,
969 /* set PF_SUPERPRIV if it turns out we allow the low mmap */
971 current
->flags
|= PF_SUPERPRIV
;