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>
23 #include "include/audit.h"
24 #include "include/apparmorfs.h"
25 #include "include/context.h"
26 #include "include/domain.h"
27 #include "include/file.h"
28 #include "include/ipc.h"
29 #include "include/match.h"
30 #include "include/path.h"
31 #include "include/policy.h"
32 #include "include/policy_ns.h"
35 * aa_free_domain_entries - free entries in a domain table
36 * @domain: the domain table to free (MAYBE NULL)
38 void aa_free_domain_entries(struct aa_domain *domain)
45 for (i = 0; i < domain->size; i++)
46 kzfree(domain->table[i]);
47 kzfree(domain->table);
53 * may_change_ptraced_domain - check if can change profile on ptraced task
54 * @to_label: profile to change to (NOT NULL)
55 * @info: message if there is an error
57 * Check if current is ptraced and if so if the tracing task is allowed
58 * to trace the new domain
60 * Returns: %0 or error if change not allowed
62 static int may_change_ptraced_domain(struct aa_label *to_label,
65 struct task_struct *tracer;
66 struct aa_label *tracerl = NULL;
70 tracer = ptrace_parent(current);
73 tracerl = aa_get_task_label(tracer);
76 if (!tracer || unconfined(tracerl))
79 error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
83 aa_put_label(tracerl);
86 *info = "ptrace prevents transition";
90 /**** TODO: dedup to aa_label_match - needs perm and dfa, merging
91 * specifically this is an exact copy of aa_label_match except
92 * aa_compute_perms is replaced with aa_compute_fperms
93 * and policy.dfa with file.dfa
95 /* match a profile and its associated ns component if needed
96 * Assumes visibility test has already been done.
97 * If a subns profile is not to be matched should be prescreened with
100 static inline unsigned int match_component(struct aa_profile *profile,
101 struct aa_profile *tp,
102 bool stack, unsigned int state)
107 state = aa_dfa_match(profile->file.dfa, state, "&");
108 if (profile->ns == tp->ns)
109 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
111 /* try matching with namespace name and then profile */
112 ns_name = aa_ns_name(profile->ns, tp->ns, true);
113 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
114 state = aa_dfa_match(profile->file.dfa, state, ns_name);
115 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
116 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
120 * label_compound_match - find perms for full compound label
121 * @profile: profile to find perms for
122 * @label: label to check access permissions for
123 * @stack: whether this is a stacking request
124 * @start: state to start match in
125 * @subns: whether to do permission checks on components in a subns
126 * @request: permissions to request
127 * @perms: perms struct to set
129 * Returns: 0 on success else ERROR
131 * For the label A//&B//&C this does the perm match for A//&B//&C
132 * @perms should be preinitialized with allperms OR a previous permission
133 * check to be stacked.
135 static int label_compound_match(struct aa_profile *profile,
136 struct aa_label *label, bool stack,
137 unsigned int state, bool subns, u32 request,
138 struct aa_perms *perms)
140 struct aa_profile *tp;
142 struct path_cond cond = { };
144 /* find first subcomponent that is visible */
145 label_for_each(i, label, tp) {
146 if (!aa_ns_visible(profile->ns, tp->ns, subns))
148 state = match_component(profile, tp, stack, state);
154 /* no component visible */
159 label_for_each_cont(i, label, tp) {
160 if (!aa_ns_visible(profile->ns, tp->ns, subns))
162 state = aa_dfa_match(profile->file.dfa, state, "//&");
163 state = match_component(profile, tp, false, state);
167 *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
168 aa_apply_modes_to_perms(profile, perms);
169 if ((perms->allow & request) != request)
180 * label_components_match - find perms for all subcomponents of a label
181 * @profile: profile to find perms for
182 * @label: label to check access permissions for
183 * @stack: whether this is a stacking request
184 * @start: state to start match in
185 * @subns: whether to do permission checks on components in a subns
186 * @request: permissions to request
187 * @perms: an initialized perms struct to add accumulation to
189 * Returns: 0 on success else ERROR
191 * For the label A//&B//&C this does the perm match for each of A and B and C
192 * @perms should be preinitialized with allperms OR a previous permission
193 * check to be stacked.
195 static int label_components_match(struct aa_profile *profile,
196 struct aa_label *label, bool stack,
197 unsigned int start, bool subns, u32 request,
198 struct aa_perms *perms)
200 struct aa_profile *tp;
203 struct path_cond cond = { };
204 unsigned int state = 0;
206 /* find first subcomponent to test */
207 label_for_each(i, label, tp) {
208 if (!aa_ns_visible(profile->ns, tp->ns, subns))
210 state = match_component(profile, tp, stack, start);
216 /* no subcomponents visible - no change in perms */
220 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
221 aa_apply_modes_to_perms(profile, &tmp);
222 aa_perms_accum(perms, &tmp);
223 label_for_each_cont(i, label, tp) {
224 if (!aa_ns_visible(profile->ns, tp->ns, subns))
226 state = match_component(profile, tp, stack, start);
229 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
230 aa_apply_modes_to_perms(profile, &tmp);
231 aa_perms_accum(perms, &tmp);
234 if ((perms->allow & request) != request)
245 * label_match - do a multi-component label match
246 * @profile: profile to match against (NOT NULL)
247 * @label: label to match (NOT NULL)
248 * @stack: whether this is a stacking request
249 * @state: state to start in
250 * @subns: whether to match subns components
251 * @request: permission request
252 * @perms: Returns computed perms (NOT NULL)
254 * Returns: the state the match finished in, may be the none matching state
256 static int label_match(struct aa_profile *profile, struct aa_label *label,
257 bool stack, unsigned int state, bool subns, u32 request,
258 struct aa_perms *perms)
263 error = label_compound_match(profile, label, stack, state, subns,
269 return label_components_match(profile, label, stack, state, subns,
273 /******* end TODO: dedup *****/
276 * change_profile_perms - find permissions for change_profile
277 * @profile: the current profile (NOT NULL)
278 * @target: label to transition to (NOT NULL)
279 * @stack: whether this is a stacking request
280 * @request: requested perms
281 * @start: state to start matching in
284 * Returns: permission set
286 * currently only matches full label A//&B//&C or individual components A, B, C
287 * not arbitrary combinations. Eg. A//&B, C
289 static int change_profile_perms(struct aa_profile *profile,
290 struct aa_label *target, bool stack,
291 u32 request, unsigned int start,
292 struct aa_perms *perms)
294 if (profile_unconfined(profile)) {
295 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
296 perms->audit = perms->quiet = perms->kill = 0;
300 /* TODO: add profile in ns screening */
301 return label_match(profile, target, stack, start, true, request, perms);
305 * __attach_match_ - find an attachment match
306 * @name - to match against (NOT NULL)
307 * @head - profile list to walk (NOT NULL)
309 * Do a linear search on the profiles in the list. There is a matching
310 * preference where an exact match is preferred over a name which uses
311 * expressions to match, and matching expressions with the greatest
312 * xmatch_len are preferred.
314 * Requires: @head not be shared or have appropriate locks held
316 * Returns: profile or NULL if no match found
318 static struct aa_profile *__attach_match(const char *name,
319 struct list_head *head)
322 struct aa_profile *profile, *candidate = NULL;
324 list_for_each_entry_rcu(profile, head, base.list) {
325 if (profile->label.flags & FLAG_NULL)
327 if (profile->xmatch && profile->xmatch_len > len) {
328 unsigned int state = aa_dfa_match(profile->xmatch,
330 u32 perm = dfa_user_allow(profile->xmatch, state);
331 /* any accepting state means a valid match. */
332 if (perm & MAY_EXEC) {
334 len = profile->xmatch_len;
336 } else if (!strcmp(profile->base.name, name))
337 /* exact non-re match, no more searching required */
345 * find_attach - do attachment search for unconfined processes
346 * @ns: the current namespace (NOT NULL)
347 * @list: list to search (NOT NULL)
348 * @name: the executable name to match against (NOT NULL)
350 * Returns: label or NULL if no match found
352 static struct aa_label *find_attach(struct aa_ns *ns, struct list_head *list,
355 struct aa_profile *profile;
358 profile = aa_get_profile(__attach_match(name, list));
361 return profile ? &profile->label : NULL;
364 static const char *next_name(int xtype, const char *name)
370 * x_table_lookup - lookup an x transition name via transition table
371 * @profile: current profile (NOT NULL)
372 * @xindex: index into x transition table
373 * @name: returns: name tested to find label (NOT NULL)
375 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
377 struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
380 struct aa_label *label = NULL;
381 u32 xtype = xindex & AA_X_TYPE_MASK;
382 int index = xindex & AA_X_INDEX_MASK;
386 /* index is guaranteed to be in range, validated at load time */
387 /* TODO: move lookup parsing to unpack time so this is a straight
388 * index into the resultant label
390 for (*name = profile->file.trans.table[index]; !label && *name;
391 *name = next_name(xtype, *name)) {
392 if (xindex & AA_X_CHILD) {
393 struct aa_profile *new_profile;
394 /* release by caller */
395 new_profile = aa_find_child(profile, *name);
397 label = &new_profile->label;
400 label = aa_label_parse(&profile->label, *name, GFP_ATOMIC,
406 /* released by caller */
412 * x_to_label - get target label for a given xindex
413 * @profile: current profile (NOT NULL)
414 * @name: name to lookup (NOT NULL)
415 * @xindex: index into x transition table
416 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
418 * find label for a transition index
420 * Returns: refcounted label or NULL if not found available
422 static struct aa_label *x_to_label(struct aa_profile *profile,
423 const char *name, u32 xindex,
424 const char **lookupname,
427 struct aa_label *new = NULL;
428 struct aa_ns *ns = profile->ns;
429 u32 xtype = xindex & AA_X_TYPE_MASK;
430 const char *stack = NULL;
434 /* fail exec unless ix || ux fallback - handled by caller */
438 /* TODO: fix when perm mapping done at unload */
439 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
441 /* released by caller */
442 new = x_table_lookup(profile, xindex, lookupname);
446 /* fall through to X_NAME */
448 if (xindex & AA_X_CHILD)
449 /* released by caller */
450 new = find_attach(ns, &profile->base.profiles,
453 /* released by caller */
454 new = find_attach(ns, &ns->base.profiles,
461 if (xindex & AA_X_INHERIT) {
462 /* (p|c|n)ix - don't change profile but do
463 * use the newest version
465 *info = "ix fallback";
466 /* no profile && no error */
467 new = aa_get_newest_label(&profile->label);
468 } else if (xindex & AA_X_UNCONFINED) {
469 new = aa_get_newest_label(ns_unconfined(profile->ns));
470 *info = "ux fallback";
475 /* base the stack on post domain transition */
476 struct aa_label *base = new;
478 new = aa_label_parse(base, stack, GFP_ATOMIC, true, false);
484 /* released by caller */
488 static struct aa_label *profile_transition(struct aa_profile *profile,
489 const struct linux_binprm *bprm,
490 char *buffer, struct path_cond *cond,
493 struct aa_label *new = NULL;
494 const char *info = NULL, *name = NULL, *target = NULL;
495 unsigned int state = profile->file.start;
496 struct aa_perms perms = {};
497 bool nonewprivs = false;
504 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
505 &name, &info, profile->disconnected);
507 if (profile_unconfined(profile) ||
508 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
509 AA_DEBUG("name lookup ix on error");
511 new = aa_get_newest_label(&profile->label);
513 name = bprm->filename;
517 if (profile_unconfined(profile)) {
518 new = find_attach(profile->ns, &profile->ns->base.profiles,
521 AA_DEBUG("unconfined attached to new label");
524 AA_DEBUG("unconfined exec no attachment");
525 return aa_get_newest_label(&profile->label);
528 /* find exec permissions for name */
529 state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
530 if (perms.allow & MAY_EXEC) {
531 /* exec permission determine how to transition */
532 new = x_to_label(profile, name, perms.xindex, &target, &info);
533 if (new && new->proxy == profile->label.proxy && info) {
534 /* hack ix fallback - improve how this is detected */
538 info = "profile transition not found";
539 /* remove MAY_EXEC to audit as failure */
540 perms.allow &= ~MAY_EXEC;
542 } else if (COMPLAIN_MODE(profile)) {
543 /* no exec permission - learning mode */
544 struct aa_profile *new_profile = aa_new_null_profile(profile,
549 info = "could not create null profile";
552 new = &new_profile->label;
554 perms.xindex |= AA_X_UNSAFE;
562 /* Policy has specified a domain transitions. if no_new_privs and
563 * confined and not transitioning to the current domain fail.
565 * NOTE: Domain transitions from unconfined and to stritly stacked
566 * subsets are allowed even when no_new_privs is set because this
567 * aways results in a further reduction of permissions.
569 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
570 !profile_unconfined(profile) &&
571 !aa_label_is_subset(new, &profile->label)) {
573 info = "no new privs";
575 perms.allow &= ~MAY_EXEC;
579 if (!(perms.xindex & AA_X_UNSAFE)) {
581 dbg_printk("apparmor: scrubbing environment variables"
582 " for %s profile=", name);
583 aa_label_printk(new, GFP_ATOMIC);
590 aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
591 cond->uid, info, error);
592 if (!new || nonewprivs) {
594 return ERR_PTR(error);
600 static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
601 bool stack, const struct linux_binprm *bprm,
602 char *buffer, struct path_cond *cond,
605 unsigned int state = profile->file.start;
606 struct aa_perms perms = {};
607 const char *xname = NULL, *info = "change_profile onexec";
615 if (profile_unconfined(profile)) {
616 /* change_profile on exec already granted */
618 * NOTE: Domain transitions from unconfined are allowed
619 * even when no_new_privs is set because this aways results
620 * in a further reduction of permissions.
625 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
626 &xname, &info, profile->disconnected);
628 if (profile_unconfined(profile) ||
629 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
630 AA_DEBUG("name lookup ix on error");
633 xname = bprm->filename;
637 /* find exec permissions for name */
638 state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
639 if (!(perms.allow & AA_MAY_ONEXEC)) {
640 info = "no change_onexec valid for executable";
643 /* test if this exec can be paired with change_profile onexec.
644 * onexec permission is linked to exec with a standard pairing
645 * exec\0change_profile
647 state = aa_dfa_null_transition(profile->file.dfa, state);
648 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
651 perms.allow &= ~AA_MAY_ONEXEC;
654 /* Policy has specified a domain transitions. if no_new_privs and
655 * confined and not transitioning to the current domain fail.
657 * NOTE: Domain transitions from unconfined and to stritly stacked
658 * subsets are allowed even when no_new_privs is set because this
659 * aways results in a further reduction of permissions.
661 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
662 !profile_unconfined(profile) &&
663 !aa_label_is_subset(onexec, &profile->label)) {
665 info = "no new privs";
666 perms.allow &= ~AA_MAY_ONEXEC;
670 if (!(perms.xindex & AA_X_UNSAFE)) {
672 dbg_printk("apparmor: scrubbing environment "
673 "variables for %s label=", xname);
674 aa_label_printk(onexec, GFP_ATOMIC);
681 return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
682 NULL, onexec, cond->uid, info, error);
685 /* ensure none ns domain transitions are correctly applied with onexec */
687 static struct aa_label *handle_onexec(struct aa_label *label,
688 struct aa_label *onexec, bool stack,
689 const struct linux_binprm *bprm,
690 char *buffer, struct path_cond *cond,
693 struct aa_profile *profile;
694 struct aa_label *new;
703 error = fn_for_each_in_ns(label, profile,
704 profile_onexec(profile, onexec, stack,
705 bprm, buffer, cond, unsafe));
707 return ERR_PTR(error);
708 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
709 aa_get_newest_label(onexec),
710 profile_transition(profile, bprm, buffer,
714 /* TODO: determine how much we want to losen this */
715 error = fn_for_each_in_ns(label, profile,
716 profile_onexec(profile, onexec, stack, bprm,
717 buffer, cond, unsafe));
719 return ERR_PTR(error);
720 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
721 aa_label_merge(&profile->label, onexec,
723 profile_transition(profile, bprm, buffer,
730 /* TODO: get rid of GLOBAL_ROOT_UID */
731 error = fn_for_each_in_ns(label, profile,
732 aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
733 AA_MAY_ONEXEC, bprm->filename, NULL,
734 onexec, GLOBAL_ROOT_UID,
735 "failed to build target label", -ENOMEM));
736 return ERR_PTR(error);
740 * apparmor_bprm_set_creds - set the new creds on the bprm struct
741 * @bprm: binprm for the exec (NOT NULL)
743 * Returns: %0 or error on failure
745 * TODO: once the other paths are done see if we can't refactor into a fn
747 int apparmor_bprm_set_creds(struct linux_binprm *bprm)
749 struct aa_task_ctx *ctx;
750 struct aa_label *label, *new = NULL;
751 struct aa_profile *profile;
753 const char *info = NULL;
756 struct path_cond cond = {
757 file_inode(bprm->file)->i_uid,
758 file_inode(bprm->file)->i_mode
761 if (bprm->called_set_creds)
764 ctx = cred_ctx(bprm->cred);
767 label = aa_get_newest_label(ctx->label);
769 /* buffer freed below, name is pointer into buffer */
771 /* Test for onexec first as onexec override other x transitions. */
773 new = handle_onexec(label, ctx->onexec, ctx->token,
774 bprm, buffer, &cond, &unsafe);
776 new = fn_label_build(label, profile, GFP_ATOMIC,
777 profile_transition(profile, bprm, buffer,
782 error = PTR_ERR(new);
789 /* TODO: Add ns level no_new_privs subset test */
791 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
792 /* FIXME: currently don't mediate shared state */
796 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
797 /* TODO: test needs to be profile of label to new */
798 error = may_change_ptraced_domain(new, &info);
805 dbg_printk("scrubbing environment variables for %s "
806 "label=", bprm->filename);
807 aa_label_printk(new, GFP_ATOMIC);
810 bprm->secureexec = 1;
813 if (label->proxy != new->proxy) {
814 /* when transitioning clear unsafe personality bits */
816 dbg_printk("apparmor: clearing unsafe personality "
817 "bits. %s label=", bprm->filename);
818 aa_label_printk(new, GFP_ATOMIC);
821 bprm->per_clear |= PER_CLEAR_ON_SETID;
823 aa_put_label(ctx->label);
824 /* transfer reference, released when ctx is freed */
828 /* clear out temporary/transitional state from the context */
829 aa_clear_task_ctx_trans(ctx);
837 error = fn_for_each(label, profile,
838 aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
839 bprm->filename, NULL, new,
840 file_inode(bprm->file)->i_uid, info,
847 * Functions for self directed profile change
851 /* helper fn for change_hat
853 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
855 static struct aa_label *build_change_hat(struct aa_profile *profile,
856 const char *name, bool sibling)
858 struct aa_profile *root, *hat = NULL;
859 const char *info = NULL;
862 if (sibling && PROFILE_IS_HAT(profile)) {
863 root = aa_get_profile_rcu(&profile->parent);
864 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
865 root = aa_get_profile(profile);
867 info = "conflicting target types";
872 hat = aa_find_child(root, name);
875 if (COMPLAIN_MODE(profile)) {
876 hat = aa_new_null_profile(profile, true, name,
879 info = "failed null profile create";
884 aa_put_profile(root);
887 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
888 name, hat ? hat->base.hname : NULL,
889 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, NULL,
891 if (!hat || (error && error != -ENOENT))
892 return ERR_PTR(error);
893 /* if hat && error - complain mode, already audited and we adjust for
894 * complain mode allow by returning hat->label
899 /* helper fn for changing into a hat
901 * Returns: label for hat transition or ERR_PTR. Does not return NULL
903 static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
904 int count, int flags)
906 struct aa_profile *profile, *root, *hat = NULL;
907 struct aa_label *new;
909 bool sibling = false;
910 const char *name, *info = NULL;
917 if (PROFILE_IS_HAT(labels_profile(label)))
920 /*find first matching hat */
921 for (i = 0; i < count && !hat; i++) {
923 label_for_each_in_ns(it, labels_ns(label), label, profile) {
924 if (sibling && PROFILE_IS_HAT(profile)) {
925 root = aa_get_profile_rcu(&profile->parent);
926 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
927 root = aa_get_profile(profile);
928 } else { /* conflicting change type */
929 info = "conflicting targets types";
933 hat = aa_find_child(root, name);
934 aa_put_profile(root);
936 if (!COMPLAIN_MODE(profile))
938 /* complain mode succeed as if hat */
939 } else if (!PROFILE_IS_HAT(hat)) {
940 info = "target not hat";
947 /* found a hat for all profiles in ns */
952 /* no hats that match, find appropriate error
954 * In complain mode audit of the failure is based off of the first
955 * hat supplied. This is done due how userspace interacts with
959 label_for_each_in_ns(it, labels_ns(label), label, profile) {
960 if (!list_empty(&profile->base.profiles)) {
961 info = "hat not found";
966 info = "no hats defined";
970 label_for_each_in_ns(it, labels_ns(label), label, profile) {
972 * no target as it has failed to be found or built
974 * change_hat uses probing and should not log failures
975 * related to missing hats
977 /* TODO: get rid of GLOBAL_ROOT_UID */
978 if (count > 1 || COMPLAIN_MODE(profile)) {
979 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
980 AA_MAY_CHANGEHAT, name, NULL, NULL,
981 GLOBAL_ROOT_UID, info, error);
984 return ERR_PTR(error);
987 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
988 build_change_hat(profile, name, sibling),
989 aa_get_label(&profile->label));
991 info = "label build failed";
994 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1000 * aa_change_hat - change hat to/from subprofile
1001 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1002 * @count: number of hat names in @hats
1003 * @token: magic value to validate the hat change
1004 * @flags: flags affecting behavior of the change
1006 * Returns %0 on success, error otherwise.
1008 * Change to the first profile specified in @hats that exists, and store
1009 * the @hat_magic in the current task context. If the count == 0 and the
1010 * @token matches that stored in the current task context, return to the
1011 * top level profile.
1013 * change_hat only applies to profiles in the current ns, and each profile
1014 * in the ns must make the same transition otherwise change_hat will fail.
1016 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1018 const struct cred *cred;
1019 struct aa_task_ctx *ctx;
1020 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1021 struct aa_profile *profile;
1022 struct aa_perms perms = {};
1023 const char *info = NULL;
1027 * Fail explicitly requested domain transitions if no_new_privs.
1028 * There is no exception for unconfined as change_hat is not
1031 if (task_no_new_privs(current)) {
1032 /* not an apparmor denial per se, so don't log it */
1033 AA_DEBUG("no_new_privs - change_hat denied");
1037 /* released below */
1038 cred = get_current_cred();
1039 ctx = cred_ctx(cred);
1040 label = aa_get_newest_cred_label(cred);
1041 previous = aa_get_newest_label(ctx->previous);
1043 if (unconfined(label)) {
1044 info = "unconfined can not change_hat";
1050 new = change_hat(label, hats, count, flags);
1053 error = PTR_ERR(new);
1055 /* already audited */
1059 error = may_change_ptraced_domain(new, &info);
1063 if (flags & AA_CHANGE_TEST)
1067 error = aa_set_current_hat(new, token);
1068 if (error == -EACCES)
1069 /* kill task in case of brute force attacks */
1071 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1072 /* Return to saved label. Kill task if restore fails
1073 * to avoid brute force attacks
1076 error = aa_restore_previous_label(token);
1078 if (error == -EACCES)
1082 } /* else ignore @flags && restores when there is no saved profile */
1086 aa_put_label(previous);
1087 aa_put_label(label);
1093 info = "failed token match";
1094 perms.kill = AA_MAY_CHANGEHAT;
1097 fn_for_each_in_ns(label, profile,
1098 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1099 AA_MAY_CHANGEHAT, NULL, NULL, target,
1100 GLOBAL_ROOT_UID, info, error));
1106 static int change_profile_perms_wrapper(const char *op, const char *name,
1107 struct aa_profile *profile,
1108 struct aa_label *target, bool stack,
1109 u32 request, struct aa_perms *perms)
1111 const char *info = NULL;
1115 * Fail explicitly requested domain transitions when no_new_privs
1116 * and not unconfined OR the transition results in a stack on
1117 * the current label.
1118 * Stacking domain transitions and transitions from unconfined are
1119 * allowed even when no_new_privs is set because this aways results
1120 * in a reduction of permissions.
1122 if (task_no_new_privs(current) && !stack &&
1123 !profile_unconfined(profile) &&
1124 !aa_label_is_subset(target, &profile->label)) {
1125 info = "no new privs";
1130 error = change_profile_perms(profile, target, stack, request,
1131 profile->file.start, perms);
1133 error = aa_audit_file(profile, perms, op, request, name,
1134 NULL, target, GLOBAL_ROOT_UID, info,
1141 * aa_change_profile - perform a one-way profile transition
1142 * @fqname: name of profile may include namespace (NOT NULL)
1143 * @onexec: whether this transition is to take place immediately or at exec
1144 * @flags: flags affecting change behavior
1146 * Change to new profile @name. Unlike with hats, there is no way
1147 * to change back. If @name isn't specified the current profile name is
1149 * If @onexec then the transition is delayed until
1152 * Returns %0 on success, error otherwise.
1154 int aa_change_profile(const char *fqname, int flags)
1156 struct aa_label *label, *new = NULL, *target = NULL;
1157 struct aa_profile *profile;
1158 struct aa_perms perms = {};
1159 const char *info = NULL;
1160 const char *auditname = fqname; /* retain leading & if stack */
1161 bool stack = flags & AA_CHANGE_STACK;
1166 if (!fqname || !*fqname) {
1167 AA_DEBUG("no profile name");
1171 if (flags & AA_CHANGE_ONEXEC) {
1172 request = AA_MAY_ONEXEC;
1174 op = OP_STACK_ONEXEC;
1176 op = OP_CHANGE_ONEXEC;
1178 request = AA_MAY_CHANGE_PROFILE;
1182 op = OP_CHANGE_PROFILE;
1185 label = aa_get_current_label();
1187 if (*fqname == '&') {
1189 /* don't have label_parse() do stacking */
1192 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1193 if (IS_ERR(target)) {
1194 struct aa_profile *tprofile;
1196 info = "label not found";
1197 error = PTR_ERR(target);
1200 * TODO: fixme using labels_profile is not right - do profile
1201 * per complain profile
1203 if ((flags & AA_CHANGE_TEST) ||
1204 !COMPLAIN_MODE(labels_profile(label)))
1206 /* released below */
1207 tprofile = aa_new_null_profile(labels_profile(label), false,
1208 fqname, GFP_KERNEL);
1210 info = "failed null profile create";
1214 target = &tprofile->label;
1219 * self directed transitions only apply to current policy ns
1220 * TODO: currently requiring perms for stacking and straight change
1221 * stacking doesn't strictly need this. Determine how much
1222 * we want to loosen this restriction for stacking
1226 error = fn_for_each_in_ns(label, profile,
1227 change_profile_perms_wrapper(op, auditname,
1228 profile, target, stack,
1231 /* auditing done in change_profile_perms_wrapper */
1237 /* check if tracing task is allowed to trace target domain */
1238 error = may_change_ptraced_domain(target, &info);
1239 if (error && !fn_for_each_in_ns(label, profile,
1240 COMPLAIN_MODE(profile)))
1243 /* TODO: add permission check to allow this
1244 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1245 * info = "not a single threaded task";
1250 if (flags & AA_CHANGE_TEST)
1253 if (!(flags & AA_CHANGE_ONEXEC)) {
1254 /* only transition profiles in the current ns */
1256 new = aa_label_merge(label, target, GFP_KERNEL);
1258 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1259 aa_get_label(target),
1260 aa_get_label(&profile->label));
1261 if (IS_ERR_OR_NULL(new)) {
1262 info = "failed to build target label";
1266 error = PTR_ERR(new);
1271 error = aa_replace_current_label(new);
1273 /* full transition will be built in exec path */
1274 error = aa_set_current_onexec(target, stack);
1277 error = fn_for_each_in_ns(label, profile,
1278 aa_audit_file(profile, &perms, op, request, auditname,
1279 NULL, new ? new : target,
1280 GLOBAL_ROOT_UID, info, error));
1284 aa_put_label(target);
1285 aa_put_label(label);