2 * AppArmor security module
4 * This file contains AppArmor policy attachment and domain transitions
6 * Copyright (C) 2002-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
15 #include <linux/errno.h>
16 #include <linux/fdtable.h>
17 #include <linux/file.h>
18 #include <linux/mount.h>
19 #include <linux/syscalls.h>
20 #include <linux/tracehook.h>
21 #include <linux/personality.h>
22 #include <linux/xattr.h>
24 #include "include/audit.h"
25 #include "include/apparmorfs.h"
26 #include "include/cred.h"
27 #include "include/domain.h"
28 #include "include/file.h"
29 #include "include/ipc.h"
30 #include "include/match.h"
31 #include "include/path.h"
32 #include "include/policy.h"
33 #include "include/policy_ns.h"
36 * aa_free_domain_entries - free entries in a domain table
37 * @domain: the domain table to free (MAYBE NULL)
39 void aa_free_domain_entries(struct aa_domain *domain)
46 for (i = 0; i < domain->size; i++)
47 kzfree(domain->table[i]);
48 kzfree(domain->table);
54 * may_change_ptraced_domain - check if can change profile on ptraced task
55 * @to_label: profile to change to (NOT NULL)
56 * @info: message if there is an error
58 * Check if current is ptraced and if so if the tracing task is allowed
59 * to trace the new domain
61 * Returns: %0 or error if change not allowed
63 static int may_change_ptraced_domain(struct aa_label *to_label,
66 struct task_struct *tracer;
67 struct aa_label *tracerl = NULL;
71 tracer = ptrace_parent(current);
74 tracerl = aa_get_task_label(tracer);
77 if (!tracer || unconfined(tracerl))
80 error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
84 aa_put_label(tracerl);
87 *info = "ptrace prevents transition";
91 /**** TODO: dedup to aa_label_match - needs perm and dfa, merging
92 * specifically this is an exact copy of aa_label_match except
93 * aa_compute_perms is replaced with aa_compute_fperms
94 * and policy.dfa with file.dfa
96 /* match a profile and its associated ns component if needed
97 * Assumes visibility test has already been done.
98 * If a subns profile is not to be matched should be prescreened with
101 static inline unsigned int match_component(struct aa_profile *profile,
102 struct aa_profile *tp,
103 bool stack, unsigned int state)
108 state = aa_dfa_match(profile->file.dfa, state, "&");
109 if (profile->ns == tp->ns)
110 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
112 /* try matching with namespace name and then profile */
113 ns_name = aa_ns_name(profile->ns, tp->ns, true);
114 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
115 state = aa_dfa_match(profile->file.dfa, state, ns_name);
116 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
117 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
121 * label_compound_match - find perms for full compound label
122 * @profile: profile to find perms for
123 * @label: label to check access permissions for
124 * @stack: whether this is a stacking request
125 * @start: state to start match in
126 * @subns: whether to do permission checks on components in a subns
127 * @request: permissions to request
128 * @perms: perms struct to set
130 * Returns: 0 on success else ERROR
132 * For the label A//&B//&C this does the perm match for A//&B//&C
133 * @perms should be preinitialized with allperms OR a previous permission
134 * check to be stacked.
136 static int label_compound_match(struct aa_profile *profile,
137 struct aa_label *label, bool stack,
138 unsigned int state, bool subns, u32 request,
139 struct aa_perms *perms)
141 struct aa_profile *tp;
143 struct path_cond cond = { };
145 /* find first subcomponent that is visible */
146 label_for_each(i, label, tp) {
147 if (!aa_ns_visible(profile->ns, tp->ns, subns))
149 state = match_component(profile, tp, stack, state);
155 /* no component visible */
160 label_for_each_cont(i, label, tp) {
161 if (!aa_ns_visible(profile->ns, tp->ns, subns))
163 state = aa_dfa_match(profile->file.dfa, state, "//&");
164 state = match_component(profile, tp, false, state);
168 *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
169 aa_apply_modes_to_perms(profile, perms);
170 if ((perms->allow & request) != request)
181 * label_components_match - find perms for all subcomponents of a label
182 * @profile: profile to find perms for
183 * @label: label to check access permissions for
184 * @stack: whether this is a stacking request
185 * @start: state to start match in
186 * @subns: whether to do permission checks on components in a subns
187 * @request: permissions to request
188 * @perms: an initialized perms struct to add accumulation to
190 * Returns: 0 on success else ERROR
192 * For the label A//&B//&C this does the perm match for each of A and B and C
193 * @perms should be preinitialized with allperms OR a previous permission
194 * check to be stacked.
196 static int label_components_match(struct aa_profile *profile,
197 struct aa_label *label, bool stack,
198 unsigned int start, bool subns, u32 request,
199 struct aa_perms *perms)
201 struct aa_profile *tp;
204 struct path_cond cond = { };
205 unsigned int state = 0;
207 /* find first subcomponent to test */
208 label_for_each(i, label, tp) {
209 if (!aa_ns_visible(profile->ns, tp->ns, subns))
211 state = match_component(profile, tp, stack, start);
217 /* no subcomponents visible - no change in perms */
221 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
222 aa_apply_modes_to_perms(profile, &tmp);
223 aa_perms_accum(perms, &tmp);
224 label_for_each_cont(i, label, tp) {
225 if (!aa_ns_visible(profile->ns, tp->ns, subns))
227 state = match_component(profile, tp, stack, start);
230 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
231 aa_apply_modes_to_perms(profile, &tmp);
232 aa_perms_accum(perms, &tmp);
235 if ((perms->allow & request) != request)
246 * label_match - do a multi-component label match
247 * @profile: profile to match against (NOT NULL)
248 * @label: label to match (NOT NULL)
249 * @stack: whether this is a stacking request
250 * @state: state to start in
251 * @subns: whether to match subns components
252 * @request: permission request
253 * @perms: Returns computed perms (NOT NULL)
255 * Returns: the state the match finished in, may be the none matching state
257 static int label_match(struct aa_profile *profile, struct aa_label *label,
258 bool stack, unsigned int state, bool subns, u32 request,
259 struct aa_perms *perms)
264 error = label_compound_match(profile, label, stack, state, subns,
270 return label_components_match(profile, label, stack, state, subns,
274 /******* end TODO: dedup *****/
277 * change_profile_perms - find permissions for change_profile
278 * @profile: the current profile (NOT NULL)
279 * @target: label to transition to (NOT NULL)
280 * @stack: whether this is a stacking request
281 * @request: requested perms
282 * @start: state to start matching in
285 * Returns: permission set
287 * currently only matches full label A//&B//&C or individual components A, B, C
288 * not arbitrary combinations. Eg. A//&B, C
290 static int change_profile_perms(struct aa_profile *profile,
291 struct aa_label *target, bool stack,
292 u32 request, unsigned int start,
293 struct aa_perms *perms)
295 if (profile_unconfined(profile)) {
296 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
297 perms->audit = perms->quiet = perms->kill = 0;
301 /* TODO: add profile in ns screening */
302 return label_match(profile, target, stack, start, true, request, perms);
306 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
307 * @bprm: binprm struct for the process to validate
308 * @profile: profile to match against (NOT NULL)
309 * @state: state to start match in
311 * Returns: number of extended attributes that matched, or < 0 on error
313 static int aa_xattrs_match(const struct linux_binprm *bprm,
314 struct aa_profile *profile, unsigned int state)
320 int value_size = 0, ret = profile->xattr_count;
322 if (!bprm || !profile->xattr_count)
325 /* transition from exec match to xattr set */
326 state = aa_dfa_null_transition(profile->xmatch, state);
328 d = bprm->file->f_path.dentry;
330 for (i = 0; i < profile->xattr_count; i++) {
331 size = vfs_getxattr_alloc(d, profile->xattrs[i], &value,
332 value_size, GFP_KERNEL);
336 /* Check the xattr value, not just presence */
337 state = aa_dfa_match_len(profile->xmatch, state, value,
339 perm = dfa_user_allow(profile->xmatch, state);
340 if (!(perm & MAY_EXEC)) {
345 /* transition to next element */
346 state = aa_dfa_null_transition(profile->xmatch, state);
349 * No xattr match, so verify if transition to
350 * next element was valid. IFF so the xattr
357 /* don't count missing optional xattr as matched */
368 * __attach_match_ - find an attachment match
369 * @bprm - binprm structure of transitioning task
370 * @name - to match against (NOT NULL)
371 * @head - profile list to walk (NOT NULL)
372 * @info - info message if there was an error (NOT NULL)
374 * Do a linear search on the profiles in the list. There is a matching
375 * preference where an exact match is preferred over a name which uses
376 * expressions to match, and matching expressions with the greatest
377 * xmatch_len are preferred.
379 * Requires: @head not be shared or have appropriate locks held
381 * Returns: profile or NULL if no match found
383 static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
385 struct list_head *head,
388 int candidate_len = 0, candidate_xattrs = 0;
389 bool conflict = false;
390 struct aa_profile *profile, *candidate = NULL;
395 list_for_each_entry_rcu(profile, head, base.list) {
396 if (profile->label.flags & FLAG_NULL &&
397 &profile->label == ns_unconfined(profile->ns))
400 /* Find the "best" matching profile. Profiles must
401 * match the path and extended attributes (if any)
402 * associated with the file. A more specific path
403 * match will be preferred over a less specific one,
404 * and a match with more matching extended attributes
405 * will be preferred over one with fewer. If the best
406 * match has both the same level of path specificity
407 * and the same number of matching extended attributes
408 * as another profile, signal a conflict and refuse to
411 if (profile->xmatch) {
412 unsigned int state, count;
415 state = aa_dfa_leftmatch(profile->xmatch, DFA_START,
417 perm = dfa_user_allow(profile->xmatch, state);
418 /* any accepting state means a valid match. */
419 if (perm & MAY_EXEC) {
422 if (count < candidate_len)
425 ret = aa_xattrs_match(bprm, profile, state);
426 /* Fail matching if the xattrs don't match */
431 * TODO: allow for more flexible best match
433 * The new match isn't more specific
434 * than the current best match
436 if (count == candidate_len &&
437 ret <= candidate_xattrs) {
438 /* Match is equivalent, so conflict */
439 if (ret == candidate_xattrs)
444 /* Either the same length with more matching
445 * xattrs, or a longer match
448 candidate_len = profile->xmatch_len;
449 candidate_xattrs = ret;
452 } else if (!strcmp(profile->base.name, name))
454 * old exact non-re match, without conditionals such
455 * as xattrs. no more searching required
461 *info = "conflicting profile attachments";
469 * find_attach - do attachment search for unconfined processes
470 * @bprm - binprm structure of transitioning task
471 * @ns: the current namespace (NOT NULL)
472 * @list: list to search (NOT NULL)
473 * @name: the executable name to match against (NOT NULL)
474 * @info: info message if there was an error
476 * Returns: label or NULL if no match found
478 static struct aa_label *find_attach(const struct linux_binprm *bprm,
479 struct aa_ns *ns, struct list_head *list,
480 const char *name, const char **info)
482 struct aa_profile *profile;
485 profile = aa_get_profile(__attach_match(bprm, name, list, info));
488 return profile ? &profile->label : NULL;
491 static const char *next_name(int xtype, const char *name)
497 * x_table_lookup - lookup an x transition name via transition table
498 * @profile: current profile (NOT NULL)
499 * @xindex: index into x transition table
500 * @name: returns: name tested to find label (NOT NULL)
502 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
504 struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
507 struct aa_label *label = NULL;
508 u32 xtype = xindex & AA_X_TYPE_MASK;
509 int index = xindex & AA_X_INDEX_MASK;
513 /* index is guaranteed to be in range, validated at load time */
514 /* TODO: move lookup parsing to unpack time so this is a straight
515 * index into the resultant label
517 for (*name = profile->file.trans.table[index]; !label && *name;
518 *name = next_name(xtype, *name)) {
519 if (xindex & AA_X_CHILD) {
520 struct aa_profile *new_profile;
521 /* release by caller */
522 new_profile = aa_find_child(profile, *name);
524 label = &new_profile->label;
527 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
533 /* released by caller */
539 * x_to_label - get target label for a given xindex
540 * @profile: current profile (NOT NULL)
541 * @bprm: binprm structure of transitioning task
542 * @name: name to lookup (NOT NULL)
543 * @xindex: index into x transition table
544 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
546 * find label for a transition index
548 * Returns: refcounted label or NULL if not found available
550 static struct aa_label *x_to_label(struct aa_profile *profile,
551 const struct linux_binprm *bprm,
552 const char *name, u32 xindex,
553 const char **lookupname,
556 struct aa_label *new = NULL;
557 struct aa_ns *ns = profile->ns;
558 u32 xtype = xindex & AA_X_TYPE_MASK;
559 const char *stack = NULL;
563 /* fail exec unless ix || ux fallback - handled by caller */
567 /* TODO: fix when perm mapping done at unload */
568 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
570 /* released by caller */
571 new = x_table_lookup(profile, xindex, lookupname);
575 /* fall through - to X_NAME */
577 if (xindex & AA_X_CHILD)
578 /* released by caller */
579 new = find_attach(bprm, ns, &profile->base.profiles,
582 /* released by caller */
583 new = find_attach(bprm, ns, &ns->base.profiles,
590 if (xindex & AA_X_INHERIT) {
591 /* (p|c|n)ix - don't change profile but do
592 * use the newest version
594 *info = "ix fallback";
595 /* no profile && no error */
596 new = aa_get_newest_label(&profile->label);
597 } else if (xindex & AA_X_UNCONFINED) {
598 new = aa_get_newest_label(ns_unconfined(profile->ns));
599 *info = "ux fallback";
604 /* base the stack on post domain transition */
605 struct aa_label *base = new;
607 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
613 /* released by caller */
617 static struct aa_label *profile_transition(struct aa_profile *profile,
618 const struct linux_binprm *bprm,
619 char *buffer, struct path_cond *cond,
622 struct aa_label *new = NULL;
623 struct aa_profile *component;
625 const char *info = NULL, *name = NULL, *target = NULL;
626 unsigned int state = profile->file.start;
627 struct aa_perms perms = {};
628 bool nonewprivs = false;
635 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
636 &name, &info, profile->disconnected);
638 if (profile_unconfined(profile) ||
639 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
640 AA_DEBUG("name lookup ix on error");
642 new = aa_get_newest_label(&profile->label);
644 name = bprm->filename;
648 if (profile_unconfined(profile)) {
649 new = find_attach(bprm, profile->ns,
650 &profile->ns->base.profiles, name, &info);
652 AA_DEBUG("unconfined attached to new label");
655 AA_DEBUG("unconfined exec no attachment");
656 return aa_get_newest_label(&profile->label);
659 /* find exec permissions for name */
660 state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
661 if (perms.allow & MAY_EXEC) {
662 /* exec permission determine how to transition */
663 new = x_to_label(profile, bprm, name, perms.xindex, &target,
665 if (new && new->proxy == profile->label.proxy && info) {
666 /* hack ix fallback - improve how this is detected */
670 info = "profile transition not found";
671 /* remove MAY_EXEC to audit as failure */
672 perms.allow &= ~MAY_EXEC;
674 /* verify that each component's xattr requirements are
675 * met, and fail execution otherwise
677 label_for_each(i, new, component) {
678 if (aa_xattrs_match(bprm, component, state) <
681 info = "required xattrs not present";
682 perms.allow &= ~MAY_EXEC;
689 } else if (COMPLAIN_MODE(profile)) {
690 /* no exec permission - learning mode */
691 struct aa_profile *new_profile = NULL;
693 new_profile = aa_new_null_profile(profile, false, name,
697 info = "could not create null profile";
700 new = &new_profile->label;
702 perms.xindex |= AA_X_UNSAFE;
711 if (!(perms.xindex & AA_X_UNSAFE)) {
713 dbg_printk("apparmor: scrubbing environment variables"
714 " for %s profile=", name);
715 aa_label_printk(new, GFP_KERNEL);
722 aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
723 cond->uid, info, error);
724 if (!new || nonewprivs) {
726 return ERR_PTR(error);
732 static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
733 bool stack, const struct linux_binprm *bprm,
734 char *buffer, struct path_cond *cond,
737 unsigned int state = profile->file.start;
738 struct aa_perms perms = {};
739 const char *xname = NULL, *info = "change_profile onexec";
747 if (profile_unconfined(profile)) {
748 /* change_profile on exec already granted */
750 * NOTE: Domain transitions from unconfined are allowed
751 * even when no_new_privs is set because this aways results
752 * in a further reduction of permissions.
757 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
758 &xname, &info, profile->disconnected);
760 if (profile_unconfined(profile) ||
761 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
762 AA_DEBUG("name lookup ix on error");
765 xname = bprm->filename;
769 /* find exec permissions for name */
770 state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
771 if (!(perms.allow & AA_MAY_ONEXEC)) {
772 info = "no change_onexec valid for executable";
775 /* test if this exec can be paired with change_profile onexec.
776 * onexec permission is linked to exec with a standard pairing
777 * exec\0change_profile
779 state = aa_dfa_null_transition(profile->file.dfa, state);
780 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
783 perms.allow &= ~AA_MAY_ONEXEC;
787 if (!(perms.xindex & AA_X_UNSAFE)) {
789 dbg_printk("apparmor: scrubbing environment "
790 "variables for %s label=", xname);
791 aa_label_printk(onexec, GFP_KERNEL);
798 return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
799 NULL, onexec, cond->uid, info, error);
802 /* ensure none ns domain transitions are correctly applied with onexec */
804 static struct aa_label *handle_onexec(struct aa_label *label,
805 struct aa_label *onexec, bool stack,
806 const struct linux_binprm *bprm,
807 char *buffer, struct path_cond *cond,
810 struct aa_profile *profile;
811 struct aa_label *new;
820 error = fn_for_each_in_ns(label, profile,
821 profile_onexec(profile, onexec, stack,
822 bprm, buffer, cond, unsafe));
824 return ERR_PTR(error);
825 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
826 aa_get_newest_label(onexec),
827 profile_transition(profile, bprm, buffer,
831 /* TODO: determine how much we want to loosen this */
832 error = fn_for_each_in_ns(label, profile,
833 profile_onexec(profile, onexec, stack, bprm,
834 buffer, cond, unsafe));
836 return ERR_PTR(error);
837 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
838 aa_label_merge(&profile->label, onexec,
840 profile_transition(profile, bprm, buffer,
847 /* TODO: get rid of GLOBAL_ROOT_UID */
848 error = fn_for_each_in_ns(label, profile,
849 aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
850 AA_MAY_ONEXEC, bprm->filename, NULL,
851 onexec, GLOBAL_ROOT_UID,
852 "failed to build target label", -ENOMEM));
853 return ERR_PTR(error);
857 * apparmor_bprm_set_creds - set the new creds on the bprm struct
858 * @bprm: binprm for the exec (NOT NULL)
860 * Returns: %0 or error on failure
862 * TODO: once the other paths are done see if we can't refactor into a fn
864 int apparmor_bprm_set_creds(struct linux_binprm *bprm)
866 struct aa_task_ctx *ctx;
867 struct aa_label *label, *new = NULL;
868 struct aa_profile *profile;
870 const char *info = NULL;
873 struct path_cond cond = {
874 file_inode(bprm->file)->i_uid,
875 file_inode(bprm->file)->i_mode
878 if (bprm->called_set_creds)
881 ctx = task_ctx(current);
882 AA_BUG(!cred_label(bprm->cred));
885 label = aa_get_newest_label(cred_label(bprm->cred));
888 * Detect no new privs being set, and store the label it
889 * occurred under. Ideally this would happen when nnp
890 * is set but there isn't a good way to do that yet.
892 * Testing for unconfined must be done before the subset test
894 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
896 ctx->nnp = aa_get_label(label);
898 /* buffer freed below, name is pointer into buffer */
899 buffer = aa_get_buffer();
905 /* Test for onexec first as onexec override other x transitions. */
907 new = handle_onexec(label, ctx->onexec, ctx->token,
908 bprm, buffer, &cond, &unsafe);
910 new = fn_label_build(label, profile, GFP_KERNEL,
911 profile_transition(profile, bprm, buffer,
916 error = PTR_ERR(new);
923 /* Policy has specified a domain transitions. If no_new_privs and
924 * confined ensure the transition is to confinement that is subset
925 * of the confinement when the task entered no new privs.
927 * NOTE: Domain transitions from unconfined and to stacked
928 * subsets are allowed even when no_new_privs is set because this
929 * aways results in a further reduction of permissions.
931 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
932 !unconfined(label) && !aa_label_is_subset(new, ctx->nnp)) {
934 info = "no new privs";
938 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
939 /* FIXME: currently don't mediate shared state */
943 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
944 /* TODO: test needs to be profile of label to new */
945 error = may_change_ptraced_domain(new, &info);
952 dbg_printk("scrubbing environment variables for %s "
953 "label=", bprm->filename);
954 aa_label_printk(new, GFP_KERNEL);
957 bprm->secureexec = 1;
960 if (label->proxy != new->proxy) {
961 /* when transitioning clear unsafe personality bits */
963 dbg_printk("apparmor: clearing unsafe personality "
964 "bits. %s label=", bprm->filename);
965 aa_label_printk(new, GFP_KERNEL);
968 bprm->per_clear |= PER_CLEAR_ON_SETID;
970 aa_put_label(cred_label(bprm->cred));
971 /* transfer reference, released when cred is freed */
972 set_cred_label(bprm->cred, new);
976 aa_put_buffer(buffer);
981 error = fn_for_each(label, profile,
982 aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
983 bprm->filename, NULL, new,
984 file_inode(bprm->file)->i_uid, info,
991 * Functions for self directed profile change
995 /* helper fn for change_hat
997 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
999 static struct aa_label *build_change_hat(struct aa_profile *profile,
1000 const char *name, bool sibling)
1002 struct aa_profile *root, *hat = NULL;
1003 const char *info = NULL;
1006 if (sibling && PROFILE_IS_HAT(profile)) {
1007 root = aa_get_profile_rcu(&profile->parent);
1008 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1009 root = aa_get_profile(profile);
1011 info = "conflicting target types";
1016 hat = aa_find_child(root, name);
1019 if (COMPLAIN_MODE(profile)) {
1020 hat = aa_new_null_profile(profile, true, name,
1023 info = "failed null profile create";
1028 aa_put_profile(root);
1031 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1032 name, hat ? hat->base.hname : NULL,
1033 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1035 if (!hat || (error && error != -ENOENT))
1036 return ERR_PTR(error);
1037 /* if hat && error - complain mode, already audited and we adjust for
1038 * complain mode allow by returning hat->label
1043 /* helper fn for changing into a hat
1045 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1047 static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1048 int count, int flags)
1050 struct aa_profile *profile, *root, *hat = NULL;
1051 struct aa_label *new;
1053 bool sibling = false;
1054 const char *name, *info = NULL;
1061 if (PROFILE_IS_HAT(labels_profile(label)))
1064 /*find first matching hat */
1065 for (i = 0; i < count && !hat; i++) {
1067 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1068 if (sibling && PROFILE_IS_HAT(profile)) {
1069 root = aa_get_profile_rcu(&profile->parent);
1070 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1071 root = aa_get_profile(profile);
1072 } else { /* conflicting change type */
1073 info = "conflicting targets types";
1077 hat = aa_find_child(root, name);
1078 aa_put_profile(root);
1080 if (!COMPLAIN_MODE(profile))
1081 goto outer_continue;
1082 /* complain mode succeed as if hat */
1083 } else if (!PROFILE_IS_HAT(hat)) {
1084 info = "target not hat";
1086 aa_put_profile(hat);
1089 aa_put_profile(hat);
1091 /* found a hat for all profiles in ns */
1096 /* no hats that match, find appropriate error
1098 * In complain mode audit of the failure is based off of the first
1099 * hat supplied. This is done due how userspace interacts with
1103 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1104 if (!list_empty(&profile->base.profiles)) {
1105 info = "hat not found";
1110 info = "no hats defined";
1114 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1116 * no target as it has failed to be found or built
1118 * change_hat uses probing and should not log failures
1119 * related to missing hats
1121 /* TODO: get rid of GLOBAL_ROOT_UID */
1122 if (count > 1 || COMPLAIN_MODE(profile)) {
1123 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1124 AA_MAY_CHANGEHAT, name, NULL, NULL,
1125 GLOBAL_ROOT_UID, info, error);
1128 return ERR_PTR(error);
1131 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1132 build_change_hat(profile, name, sibling),
1133 aa_get_label(&profile->label));
1135 info = "label build failed";
1138 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1144 * aa_change_hat - change hat to/from subprofile
1145 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1146 * @count: number of hat names in @hats
1147 * @token: magic value to validate the hat change
1148 * @flags: flags affecting behavior of the change
1150 * Returns %0 on success, error otherwise.
1152 * Change to the first profile specified in @hats that exists, and store
1153 * the @hat_magic in the current task context. If the count == 0 and the
1154 * @token matches that stored in the current task context, return to the
1155 * top level profile.
1157 * change_hat only applies to profiles in the current ns, and each profile
1158 * in the ns must make the same transition otherwise change_hat will fail.
1160 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1162 const struct cred *cred;
1163 struct aa_task_ctx *ctx = task_ctx(current);
1164 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1165 struct aa_profile *profile;
1166 struct aa_perms perms = {};
1167 const char *info = NULL;
1170 /* released below */
1171 cred = get_current_cred();
1172 label = aa_get_newest_cred_label(cred);
1173 previous = aa_get_newest_label(ctx->previous);
1176 * Detect no new privs being set, and store the label it
1177 * occurred under. Ideally this would happen when nnp
1178 * is set but there isn't a good way to do that yet.
1180 * Testing for unconfined must be done before the subset test
1182 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1183 ctx->nnp = aa_get_label(label);
1185 if (unconfined(label)) {
1186 info = "unconfined can not change_hat";
1192 new = change_hat(label, hats, count, flags);
1195 error = PTR_ERR(new);
1197 /* already audited */
1201 error = may_change_ptraced_domain(new, &info);
1206 * no new privs prevents domain transitions that would
1207 * reduce restrictions.
1209 if (task_no_new_privs(current) && !unconfined(label) &&
1210 !aa_label_is_subset(new, ctx->nnp)) {
1211 /* not an apparmor denial per se, so don't log it */
1212 AA_DEBUG("no_new_privs - change_hat denied");
1217 if (flags & AA_CHANGE_TEST)
1221 error = aa_set_current_hat(new, token);
1222 if (error == -EACCES)
1223 /* kill task in case of brute force attacks */
1225 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1227 * no new privs prevents domain transitions that would
1228 * reduce restrictions.
1230 if (task_no_new_privs(current) && !unconfined(label) &&
1231 !aa_label_is_subset(previous, ctx->nnp)) {
1232 /* not an apparmor denial per se, so don't log it */
1233 AA_DEBUG("no_new_privs - change_hat denied");
1238 /* Return to saved label. Kill task if restore fails
1239 * to avoid brute force attacks
1242 error = aa_restore_previous_label(token);
1244 if (error == -EACCES)
1248 } /* else ignore @flags && restores when there is no saved profile */
1252 aa_put_label(previous);
1253 aa_put_label(label);
1259 info = "failed token match";
1260 perms.kill = AA_MAY_CHANGEHAT;
1263 fn_for_each_in_ns(label, profile,
1264 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1265 AA_MAY_CHANGEHAT, NULL, NULL, target,
1266 GLOBAL_ROOT_UID, info, error));
1272 static int change_profile_perms_wrapper(const char *op, const char *name,
1273 struct aa_profile *profile,
1274 struct aa_label *target, bool stack,
1275 u32 request, struct aa_perms *perms)
1277 const char *info = NULL;
1281 error = change_profile_perms(profile, target, stack, request,
1282 profile->file.start, perms);
1284 error = aa_audit_file(profile, perms, op, request, name,
1285 NULL, target, GLOBAL_ROOT_UID, info,
1292 * aa_change_profile - perform a one-way profile transition
1293 * @fqname: name of profile may include namespace (NOT NULL)
1294 * @onexec: whether this transition is to take place immediately or at exec
1295 * @flags: flags affecting change behavior
1297 * Change to new profile @name. Unlike with hats, there is no way
1298 * to change back. If @name isn't specified the current profile name is
1300 * If @onexec then the transition is delayed until
1303 * Returns %0 on success, error otherwise.
1305 int aa_change_profile(const char *fqname, int flags)
1307 struct aa_label *label, *new = NULL, *target = NULL;
1308 struct aa_profile *profile;
1309 struct aa_perms perms = {};
1310 const char *info = NULL;
1311 const char *auditname = fqname; /* retain leading & if stack */
1312 bool stack = flags & AA_CHANGE_STACK;
1313 struct aa_task_ctx *ctx = task_ctx(current);
1318 label = aa_get_current_label();
1321 * Detect no new privs being set, and store the label it
1322 * occurred under. Ideally this would happen when nnp
1323 * is set but there isn't a good way to do that yet.
1325 * Testing for unconfined must be done before the subset test
1327 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1328 ctx->nnp = aa_get_label(label);
1330 if (!fqname || !*fqname) {
1331 AA_DEBUG("no profile name");
1335 if (flags & AA_CHANGE_ONEXEC) {
1336 request = AA_MAY_ONEXEC;
1338 op = OP_STACK_ONEXEC;
1340 op = OP_CHANGE_ONEXEC;
1342 request = AA_MAY_CHANGE_PROFILE;
1346 op = OP_CHANGE_PROFILE;
1349 label = aa_get_current_label();
1351 if (*fqname == '&') {
1353 /* don't have label_parse() do stacking */
1356 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1357 if (IS_ERR(target)) {
1358 struct aa_profile *tprofile;
1360 info = "label not found";
1361 error = PTR_ERR(target);
1364 * TODO: fixme using labels_profile is not right - do profile
1365 * per complain profile
1367 if ((flags & AA_CHANGE_TEST) ||
1368 !COMPLAIN_MODE(labels_profile(label)))
1370 /* released below */
1371 tprofile = aa_new_null_profile(labels_profile(label), false,
1372 fqname, GFP_KERNEL);
1374 info = "failed null profile create";
1378 target = &tprofile->label;
1383 * self directed transitions only apply to current policy ns
1384 * TODO: currently requiring perms for stacking and straight change
1385 * stacking doesn't strictly need this. Determine how much
1386 * we want to loosen this restriction for stacking
1390 error = fn_for_each_in_ns(label, profile,
1391 change_profile_perms_wrapper(op, auditname,
1392 profile, target, stack,
1395 /* auditing done in change_profile_perms_wrapper */
1401 /* check if tracing task is allowed to trace target domain */
1402 error = may_change_ptraced_domain(target, &info);
1403 if (error && !fn_for_each_in_ns(label, profile,
1404 COMPLAIN_MODE(profile)))
1407 /* TODO: add permission check to allow this
1408 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1409 * info = "not a single threaded task";
1414 if (flags & AA_CHANGE_TEST)
1417 /* stacking is always a subset, so only check the nonstack case */
1419 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1420 aa_get_label(target),
1421 aa_get_label(&profile->label));
1423 * no new privs prevents domain transitions that would
1424 * reduce restrictions.
1426 if (task_no_new_privs(current) && !unconfined(label) &&
1427 !aa_label_is_subset(new, ctx->nnp)) {
1428 /* not an apparmor denial per se, so don't log it */
1429 AA_DEBUG("no_new_privs - change_hat denied");
1435 if (!(flags & AA_CHANGE_ONEXEC)) {
1436 /* only transition profiles in the current ns */
1438 new = aa_label_merge(label, target, GFP_KERNEL);
1439 if (IS_ERR_OR_NULL(new)) {
1440 info = "failed to build target label";
1444 error = PTR_ERR(new);
1449 error = aa_replace_current_label(new);
1456 /* full transition will be built in exec path */
1457 error = aa_set_current_onexec(target, stack);
1461 error = fn_for_each_in_ns(label, profile,
1462 aa_audit_file(profile, &perms, op, request, auditname,
1463 NULL, new ? new : target,
1464 GLOBAL_ROOT_UID, info, error));
1468 aa_put_label(target);
1469 aa_put_label(label);