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 owner of the user namespace has all caps. */
81 if (targ_ns != &init_user_ns && uid_eq(targ_ns->owner, cred->euid))
84 /* Do we have the necessary capabilities? */
85 if (targ_ns == cred->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->parent;
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_ns == child_cred->user_ns &&
141 cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
143 if (ns_capable(child_cred->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_ns == child_cred->user_ns &&
173 cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
175 if (has_ns_capability(parent, child_cred->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_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;
479 ret = get_file_caps(bprm, &effective, &has_cap);
483 root_uid = make_kuid(new->user_ns, 0);
485 if (!issecure(SECURE_NOROOT)) {
487 * If the legacy file capability is set, then don't set privs
488 * for a setuid root binary run by a non-root user. Do set it
489 * for a root user just to cause least surprise to an admin.
491 if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) {
492 warn_setuid_and_fcaps_mixed(bprm->filename);
496 * To support inheritance of root-permissions and suid-root
497 * executables under compatibility mode, we override the
498 * capability sets for the file.
500 * If only the real uid is 0, we do not set the effective bit.
502 if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) {
503 /* pP' = (cap_bset & ~0) | (pI & ~0) */
504 new->cap_permitted = cap_combine(old->cap_bset,
505 old->cap_inheritable);
507 if (uid_eq(new->euid, root_uid))
512 /* if we have fs caps, clear dangerous personality flags */
513 if (!cap_issubset(new->cap_permitted, old->cap_permitted))
514 bprm->per_clear |= PER_CLEAR_ON_SETID;
517 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
518 * credentials unless they have the appropriate permit.
520 * In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
522 if ((!uid_eq(new->euid, old->uid) ||
523 !gid_eq(new->egid, old->gid) ||
524 !cap_issubset(new->cap_permitted, old->cap_permitted)) &&
525 bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
526 /* downgrade; they get no more than they had, and maybe less */
527 if (!capable(CAP_SETUID) ||
528 (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)) {
529 new->euid = new->uid;
530 new->egid = new->gid;
532 new->cap_permitted = cap_intersect(new->cap_permitted,
536 new->suid = new->fsuid = new->euid;
537 new->sgid = new->fsgid = new->egid;
540 new->cap_effective = new->cap_permitted;
542 cap_clear(new->cap_effective);
543 bprm->cap_effective = effective;
546 * Audit candidate if current->cap_effective is set
548 * We do not bother to audit if 3 things are true:
549 * 1) cap_effective has all caps
551 * 3) root is supposed to have all caps (SECURE_NOROOT)
552 * Since this is just a normal root execing a process.
554 * Number 1 above might fail if you don't have a full bset, but I think
555 * that is interesting information to audit.
557 if (!cap_isclear(new->cap_effective)) {
558 if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
559 !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) ||
560 issecure(SECURE_NOROOT)) {
561 ret = audit_log_bprm_fcaps(bprm, new, old);
567 new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
572 * cap_bprm_secureexec - Determine whether a secure execution is required
573 * @bprm: The execution parameters
575 * Determine whether a secure execution is required, return 1 if it is, and 0
578 * The credentials have been committed by this point, and so are no longer
579 * available through @bprm->cred.
581 int cap_bprm_secureexec(struct linux_binprm *bprm)
583 const struct cred *cred = current_cred();
584 kuid_t root_uid = make_kuid(cred->user_ns, 0);
586 if (!uid_eq(cred->uid, root_uid)) {
587 if (bprm->cap_effective)
589 if (!cap_isclear(cred->cap_permitted))
593 return (!uid_eq(cred->euid, cred->uid) ||
594 !gid_eq(cred->egid, cred->gid));
598 * cap_inode_setxattr - Determine whether an xattr may be altered
599 * @dentry: The inode/dentry being altered
600 * @name: The name of the xattr to be changed
601 * @value: The value that the xattr will be changed to
602 * @size: The size of value
603 * @flags: The replacement flag
605 * Determine whether an xattr may be altered or set on an inode, returning 0 if
606 * permission is granted, -ve if denied.
608 * This is used to make sure security xattrs don't get updated or set by those
609 * who aren't privileged to do so.
611 int cap_inode_setxattr(struct dentry *dentry, const char *name,
612 const void *value, size_t size, int flags)
614 if (!strcmp(name, XATTR_NAME_CAPS)) {
615 if (!capable(CAP_SETFCAP))
620 if (!strncmp(name, XATTR_SECURITY_PREFIX,
621 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
622 !capable(CAP_SYS_ADMIN))
628 * cap_inode_removexattr - Determine whether an xattr may be removed
629 * @dentry: The inode/dentry being altered
630 * @name: The name of the xattr to be changed
632 * Determine whether an xattr may be removed from an inode, returning 0 if
633 * permission is granted, -ve if denied.
635 * This is used to make sure security xattrs don't get removed by those who
636 * aren't privileged to remove them.
638 int cap_inode_removexattr(struct dentry *dentry, const char *name)
640 if (!strcmp(name, XATTR_NAME_CAPS)) {
641 if (!capable(CAP_SETFCAP))
646 if (!strncmp(name, XATTR_SECURITY_PREFIX,
647 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
648 !capable(CAP_SYS_ADMIN))
654 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
655 * a process after a call to setuid, setreuid, or setresuid.
657 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
658 * {r,e,s}uid != 0, the permitted and effective capabilities are
661 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
662 * capabilities of the process are cleared.
664 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
665 * capabilities are set to the permitted capabilities.
667 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
672 * cevans - New behaviour, Oct '99
673 * A process may, via prctl(), elect to keep its capabilities when it
674 * calls setuid() and switches away from uid==0. Both permitted and
675 * effective sets will be retained.
676 * Without this change, it was impossible for a daemon to drop only some
677 * of its privilege. The call to setuid(!=0) would drop all privileges!
678 * Keeping uid 0 is not an option because uid 0 owns too many vital
680 * Thanks to Olaf Kirch and Peter Benie for spotting this.
682 static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
684 kuid_t root_uid = make_kuid(old->user_ns, 0);
686 if ((uid_eq(old->uid, root_uid) ||
687 uid_eq(old->euid, root_uid) ||
688 uid_eq(old->suid, root_uid)) &&
689 (!uid_eq(new->uid, root_uid) &&
690 !uid_eq(new->euid, root_uid) &&
691 !uid_eq(new->suid, root_uid)) &&
692 !issecure(SECURE_KEEP_CAPS)) {
693 cap_clear(new->cap_permitted);
694 cap_clear(new->cap_effective);
696 if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid))
697 cap_clear(new->cap_effective);
698 if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid))
699 new->cap_effective = new->cap_permitted;
703 * cap_task_fix_setuid - Fix up the results of setuid() call
704 * @new: The proposed credentials
705 * @old: The current task's current credentials
706 * @flags: Indications of what has changed
708 * Fix up the results of setuid() call before the credential changes are
709 * actually applied, returning 0 to grant the changes, -ve to deny them.
711 int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
717 /* juggle the capabilities to follow [RES]UID changes unless
718 * otherwise suppressed */
719 if (!issecure(SECURE_NO_SETUID_FIXUP))
720 cap_emulate_setxuid(new, old);
724 /* juggle the capabilties to follow FSUID changes, unless
725 * otherwise suppressed
727 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
728 * if not, we might be a bit too harsh here.
730 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
731 kuid_t root_uid = make_kuid(old->user_ns, 0);
732 if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid))
734 cap_drop_fs_set(new->cap_effective);
736 if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid))
738 cap_raise_fs_set(new->cap_effective,
751 * Rationale: code calling task_setscheduler, task_setioprio, and
752 * task_setnice, assumes that
753 * . if capable(cap_sys_nice), then those actions should be allowed
754 * . if not capable(cap_sys_nice), but acting on your own processes,
755 * then those actions should be allowed
756 * This is insufficient now since you can call code without suid, but
757 * yet with increased caps.
758 * So we check for increased caps on the target process.
760 static int cap_safe_nice(struct task_struct *p)
765 is_subset = cap_issubset(__task_cred(p)->cap_permitted,
766 current_cred()->cap_permitted);
769 if (!is_subset && !capable(CAP_SYS_NICE))
775 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
776 * @p: The task to affect
778 * Detemine if the requested scheduler policy change is permitted for the
779 * specified task, returning 0 if permission is granted, -ve if denied.
781 int cap_task_setscheduler(struct task_struct *p)
783 return cap_safe_nice(p);
787 * cap_task_ioprio - Detemine if I/O priority change is permitted
788 * @p: The task to affect
789 * @ioprio: The I/O priority to set
791 * Detemine if the requested I/O priority change is permitted for the specified
792 * task, returning 0 if permission is granted, -ve if denied.
794 int cap_task_setioprio(struct task_struct *p, int ioprio)
796 return cap_safe_nice(p);
800 * cap_task_ioprio - Detemine if task priority change is permitted
801 * @p: The task to affect
802 * @nice: The nice value to set
804 * Detemine if the requested task priority change is permitted for the
805 * specified task, returning 0 if permission is granted, -ve if denied.
807 int cap_task_setnice(struct task_struct *p, int nice)
809 return cap_safe_nice(p);
813 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
814 * the current task's bounding set. Returns 0 on success, -ve on error.
816 static long cap_prctl_drop(struct cred *new, unsigned long cap)
818 if (!capable(CAP_SETPCAP))
823 cap_lower(new->cap_bset, cap);
828 * cap_task_prctl - Implement process control functions for this security module
829 * @option: The process control function requested
830 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
832 * Allow process control functions (sys_prctl()) to alter capabilities; may
833 * also deny access to other functions not otherwise implemented here.
835 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
836 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
837 * modules will consider performing the function.
839 int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
840 unsigned long arg4, unsigned long arg5)
845 new = prepare_creds();
850 case PR_CAPBSET_READ:
852 if (!cap_valid(arg2))
854 error = !!cap_raised(new->cap_bset, arg2);
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(current_cred(),
889 current_cred()->user_ns, CAP_SETPCAP,
890 SECURITY_CAP_AUDIT) != 0) /*[4]*/
892 * [1] no changing of bits that are locked
893 * [2] no unlocking of locks
894 * [3] no setting of unsupported bits
895 * [4] doing anything requires privilege (go read about
896 * the "sendmail capabilities bug")
899 /* cannot change a locked bit */
901 new->securebits = arg2;
904 case PR_GET_SECUREBITS:
905 error = new->securebits;
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);
943 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
944 * @mm: The VM space in which the new mapping is to be made
945 * @pages: The size of the mapping
947 * Determine whether the allocation of a new virtual mapping by the current
948 * task is permitted, returning 0 if permission is granted, -ve if not.
950 int cap_vm_enough_memory(struct mm_struct *mm, long pages)
952 int cap_sys_admin = 0;
954 if (cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN,
955 SECURITY_CAP_NOAUDIT) == 0)
957 return __vm_enough_memory(mm, pages, cap_sys_admin);
961 * cap_mmap_addr - check if able to map given addr
962 * @addr: address attempting to be mapped
964 * If the process is attempting to map memory below dac_mmap_min_addr they need
965 * CAP_SYS_RAWIO. The other parameters to this function are unused by the
966 * capability security module. Returns 0 if this mapping should be allowed
969 int cap_mmap_addr(unsigned long addr)
973 if (addr < dac_mmap_min_addr) {
974 ret = cap_capable(current_cred(), &init_user_ns, CAP_SYS_RAWIO,
976 /* set PF_SUPERPRIV if it turns out we allow the low mmap */
978 current->flags |= PF_SUPERPRIV;
983 int cap_mmap_file(struct file *file, unsigned long reqprot,
984 unsigned long prot, unsigned long flags)