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Linux/security/apparmor/domain.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * AppArmor security module
  4  *
  5  * This file contains AppArmor policy attachment and domain transitions
  6  *
  7  * Copyright (C) 2002-2008 Novell/SUSE
  8  * Copyright 2009-2010 Canonical Ltd.
  9  */
 10 
 11 #include <linux/errno.h>
 12 #include <linux/fdtable.h>
 13 #include <linux/fs.h>
 14 #include <linux/file.h>
 15 #include <linux/mount.h>
 16 #include <linux/syscalls.h>
 17 #include <linux/personality.h>
 18 #include <linux/xattr.h>
 19 #include <linux/user_namespace.h>
 20 
 21 #include "include/audit.h"
 22 #include "include/apparmorfs.h"
 23 #include "include/cred.h"
 24 #include "include/domain.h"
 25 #include "include/file.h"
 26 #include "include/ipc.h"
 27 #include "include/match.h"
 28 #include "include/path.h"
 29 #include "include/policy.h"
 30 #include "include/policy_ns.h"
 31 
 32 /**
 33  * may_change_ptraced_domain - check if can change profile on ptraced task
 34  * @to_cred: cred of task changing domain
 35  * @to_label: profile to change to  (NOT NULL)
 36  * @info: message if there is an error
 37  *
 38  * Check if current is ptraced and if so if the tracing task is allowed
 39  * to trace the new domain
 40  *
 41  * Returns: %0 or error if change not allowed
 42  */
 43 static int may_change_ptraced_domain(const struct cred *to_cred,
 44                                      struct aa_label *to_label,
 45                                      const char **info)
 46 {
 47         struct task_struct *tracer;
 48         struct aa_label *tracerl = NULL;
 49         const struct cred *tracer_cred = NULL;
 50 
 51         int error = 0;
 52 
 53         rcu_read_lock();
 54         tracer = ptrace_parent(current);
 55         if (tracer) {
 56                 /* released below */
 57                 tracerl = aa_get_task_label(tracer);
 58                 tracer_cred = get_task_cred(tracer);
 59         }
 60         /* not ptraced */
 61         if (!tracer || unconfined(tracerl))
 62                 goto out;
 63 
 64         error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
 65                               PTRACE_MODE_ATTACH);
 66 
 67 out:
 68         rcu_read_unlock();
 69         aa_put_label(tracerl);
 70         put_cred(tracer_cred);
 71 
 72         if (error)
 73                 *info = "ptrace prevents transition";
 74         return error;
 75 }
 76 
 77 /**** TODO: dedup to aa_label_match - needs perm and dfa, merging
 78  * specifically this is an exact copy of aa_label_match except
 79  * aa_compute_perms is replaced with aa_compute_fperms
 80  * and policy->dfa with file->dfa
 81  ****/
 82 /* match a profile and its associated ns component if needed
 83  * Assumes visibility test has already been done.
 84  * If a subns profile is not to be matched should be prescreened with
 85  * visibility test.
 86  */
 87 static inline aa_state_t match_component(struct aa_profile *profile,
 88                                          struct aa_profile *tp,
 89                                          bool stack, aa_state_t state)
 90 {
 91         struct aa_ruleset *rules = list_first_entry(&profile->rules,
 92                                                     typeof(*rules), list);
 93         const char *ns_name;
 94 
 95         if (stack)
 96                 state = aa_dfa_match(rules->file->dfa, state, "&");
 97         if (profile->ns == tp->ns)
 98                 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
 99 
100         /* try matching with namespace name and then profile */
101         ns_name = aa_ns_name(profile->ns, tp->ns, true);
102         state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
103         state = aa_dfa_match(rules->file->dfa, state, ns_name);
104         state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
105         return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
106 }
107 
108 /**
109  * label_compound_match - find perms for full compound label
110  * @profile: profile to find perms for
111  * @label: label to check access permissions for
112  * @stack: whether this is a stacking request
113  * @state: state to start match in
114  * @subns: whether to do permission checks on components in a subns
115  * @request: permissions to request
116  * @perms: perms struct to set
117  *
118  * Returns: 0 on success else ERROR
119  *
120  * For the label A//&B//&C this does the perm match for A//&B//&C
121  * @perms should be preinitialized with allperms OR a previous permission
122  *        check to be stacked.
123  */
124 static int label_compound_match(struct aa_profile *profile,
125                                 struct aa_label *label, bool stack,
126                                 aa_state_t state, bool subns, u32 request,
127                                 struct aa_perms *perms)
128 {
129         struct aa_ruleset *rules = list_first_entry(&profile->rules,
130                                                     typeof(*rules), list);
131         struct aa_profile *tp;
132         struct label_it i;
133         struct path_cond cond = { };
134 
135         /* find first subcomponent that is visible */
136         label_for_each(i, label, tp) {
137                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
138                         continue;
139                 state = match_component(profile, tp, stack, state);
140                 if (!state)
141                         goto fail;
142                 goto next;
143         }
144 
145         /* no component visible */
146         *perms = allperms;
147         return 0;
148 
149 next:
150         label_for_each_cont(i, label, tp) {
151                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
152                         continue;
153                 state = aa_dfa_match(rules->file->dfa, state, "//&");
154                 state = match_component(profile, tp, false, state);
155                 if (!state)
156                         goto fail;
157         }
158         *perms = *(aa_lookup_fperms(rules->file, state, &cond));
159         aa_apply_modes_to_perms(profile, perms);
160         if ((perms->allow & request) != request)
161                 return -EACCES;
162 
163         return 0;
164 
165 fail:
166         *perms = nullperms;
167         return -EACCES;
168 }
169 
170 /**
171  * label_components_match - find perms for all subcomponents of a label
172  * @profile: profile to find perms for
173  * @label: label to check access permissions for
174  * @stack: whether this is a stacking request
175  * @start: state to start match in
176  * @subns: whether to do permission checks on components in a subns
177  * @request: permissions to request
178  * @perms: an initialized perms struct to add accumulation to
179  *
180  * Returns: 0 on success else ERROR
181  *
182  * For the label A//&B//&C this does the perm match for each of A and B and C
183  * @perms should be preinitialized with allperms OR a previous permission
184  *        check to be stacked.
185  */
186 static int label_components_match(struct aa_profile *profile,
187                                   struct aa_label *label, bool stack,
188                                   aa_state_t start, bool subns, u32 request,
189                                   struct aa_perms *perms)
190 {
191         struct aa_ruleset *rules = list_first_entry(&profile->rules,
192                                                     typeof(*rules), list);
193         struct aa_profile *tp;
194         struct label_it i;
195         struct aa_perms tmp;
196         struct path_cond cond = { };
197         aa_state_t state = 0;
198 
199         /* find first subcomponent to test */
200         label_for_each(i, label, tp) {
201                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
202                         continue;
203                 state = match_component(profile, tp, stack, start);
204                 if (!state)
205                         goto fail;
206                 goto next;
207         }
208 
209         /* no subcomponents visible - no change in perms */
210         return 0;
211 
212 next:
213         tmp = *(aa_lookup_fperms(rules->file, state, &cond));
214         aa_apply_modes_to_perms(profile, &tmp);
215         aa_perms_accum(perms, &tmp);
216         label_for_each_cont(i, label, tp) {
217                 if (!aa_ns_visible(profile->ns, tp->ns, subns))
218                         continue;
219                 state = match_component(profile, tp, stack, start);
220                 if (!state)
221                         goto fail;
222                 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
223                 aa_apply_modes_to_perms(profile, &tmp);
224                 aa_perms_accum(perms, &tmp);
225         }
226 
227         if ((perms->allow & request) != request)
228                 return -EACCES;
229 
230         return 0;
231 
232 fail:
233         *perms = nullperms;
234         return -EACCES;
235 }
236 
237 /**
238  * label_match - do a multi-component label match
239  * @profile: profile to match against (NOT NULL)
240  * @label: label to match (NOT NULL)
241  * @stack: whether this is a stacking request
242  * @state: state to start in
243  * @subns: whether to match subns components
244  * @request: permission request
245  * @perms: Returns computed perms (NOT NULL)
246  *
247  * Returns: the state the match finished in, may be the none matching state
248  */
249 static int label_match(struct aa_profile *profile, struct aa_label *label,
250                        bool stack, aa_state_t state, bool subns, u32 request,
251                        struct aa_perms *perms)
252 {
253         int error;
254 
255         *perms = nullperms;
256         error = label_compound_match(profile, label, stack, state, subns,
257                                      request, perms);
258         if (!error)
259                 return error;
260 
261         *perms = allperms;
262         return label_components_match(profile, label, stack, state, subns,
263                                       request, perms);
264 }
265 
266 /******* end TODO: dedup *****/
267 
268 /**
269  * change_profile_perms - find permissions for change_profile
270  * @profile: the current profile  (NOT NULL)
271  * @target: label to transition to (NOT NULL)
272  * @stack: whether this is a stacking request
273  * @request: requested perms
274  * @start: state to start matching in
275  * @perms: Returns computed perms (NOT NULL)
276  *
277  *
278  * Returns: permission set
279  *
280  * currently only matches full label A//&B//&C or individual components A, B, C
281  * not arbitrary combinations. Eg. A//&B, C
282  */
283 static int change_profile_perms(struct aa_profile *profile,
284                                 struct aa_label *target, bool stack,
285                                 u32 request, aa_state_t start,
286                                 struct aa_perms *perms)
287 {
288         if (profile_unconfined(profile)) {
289                 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
290                 perms->audit = perms->quiet = perms->kill = 0;
291                 return 0;
292         }
293 
294         /* TODO: add profile in ns screening */
295         return label_match(profile, target, stack, start, true, request, perms);
296 }
297 
298 /**
299  * aa_xattrs_match - check whether a file matches the xattrs defined in profile
300  * @bprm: binprm struct for the process to validate
301  * @profile: profile to match against (NOT NULL)
302  * @state: state to start match in
303  *
304  * Returns: number of extended attributes that matched, or < 0 on error
305  */
306 static int aa_xattrs_match(const struct linux_binprm *bprm,
307                            struct aa_profile *profile, aa_state_t state)
308 {
309         int i;
310         struct dentry *d;
311         char *value = NULL;
312         struct aa_attachment *attach = &profile->attach;
313         int size, value_size = 0, ret = attach->xattr_count;
314 
315         if (!bprm || !attach->xattr_count)
316                 return 0;
317         might_sleep();
318 
319         /* transition from exec match to xattr set */
320         state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
321         d = bprm->file->f_path.dentry;
322 
323         for (i = 0; i < attach->xattr_count; i++) {
324                 size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
325                                           &value, value_size, GFP_KERNEL);
326                 if (size >= 0) {
327                         u32 index, perm;
328 
329                         /*
330                          * Check the xattr presence before value. This ensure
331                          * that not present xattr can be distinguished from a 0
332                          * length value or rule that matches any value
333                          */
334                         state = aa_dfa_null_transition(attach->xmatch->dfa,
335                                                        state);
336                         /* Check xattr value */
337                         state = aa_dfa_match_len(attach->xmatch->dfa, state,
338                                                  value, size);
339                         index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
340                         perm = attach->xmatch->perms[index].allow;
341                         if (!(perm & MAY_EXEC)) {
342                                 ret = -EINVAL;
343                                 goto out;
344                         }
345                 }
346                 /* transition to next element */
347                 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
348                 if (size < 0) {
349                         /*
350                          * No xattr match, so verify if transition to
351                          * next element was valid. IFF so the xattr
352                          * was optional.
353                          */
354                         if (!state) {
355                                 ret = -EINVAL;
356                                 goto out;
357                         }
358                         /* don't count missing optional xattr as matched */
359                         ret--;
360                 }
361         }
362 
363 out:
364         kfree(value);
365         return ret;
366 }
367 
368 /**
369  * find_attach - do attachment search for unconfined processes
370  * @bprm: binprm structure of transitioning task
371  * @ns: the current namespace  (NOT NULL)
372  * @head: profile list to walk  (NOT NULL)
373  * @name: to match against  (NOT NULL)
374  * @info: info message if there was an error (NOT NULL)
375  *
376  * Do a linear search on the profiles in the list.  There is a matching
377  * preference where an exact match is preferred over a name which uses
378  * expressions to match, and matching expressions with the greatest
379  * xmatch_len are preferred.
380  *
381  * Requires: @head not be shared or have appropriate locks held
382  *
383  * Returns: label or NULL if no match found
384  */
385 static struct aa_label *find_attach(const struct linux_binprm *bprm,
386                                     struct aa_ns *ns, struct list_head *head,
387                                     const char *name, const char **info)
388 {
389         int candidate_len = 0, candidate_xattrs = 0;
390         bool conflict = false;
391         struct aa_profile *profile, *candidate = NULL;
392 
393         AA_BUG(!name);
394         AA_BUG(!head);
395 
396         rcu_read_lock();
397 restart:
398         list_for_each_entry_rcu(profile, head, base.list) {
399                 struct aa_attachment *attach = &profile->attach;
400 
401                 if (profile->label.flags & FLAG_NULL &&
402                     &profile->label == ns_unconfined(profile->ns))
403                         continue;
404 
405                 /* Find the "best" matching profile. Profiles must
406                  * match the path and extended attributes (if any)
407                  * associated with the file. A more specific path
408                  * match will be preferred over a less specific one,
409                  * and a match with more matching extended attributes
410                  * will be preferred over one with fewer. If the best
411                  * match has both the same level of path specificity
412                  * and the same number of matching extended attributes
413                  * as another profile, signal a conflict and refuse to
414                  * match.
415                  */
416                 if (attach->xmatch->dfa) {
417                         unsigned int count;
418                         aa_state_t state;
419                         u32 index, perm;
420 
421                         state = aa_dfa_leftmatch(attach->xmatch->dfa,
422                                         attach->xmatch->start[AA_CLASS_XMATCH],
423                                         name, &count);
424                         index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
425                         perm = attach->xmatch->perms[index].allow;
426                         /* any accepting state means a valid match. */
427                         if (perm & MAY_EXEC) {
428                                 int ret = 0;
429 
430                                 if (count < candidate_len)
431                                         continue;
432 
433                                 if (bprm && attach->xattr_count) {
434                                         long rev = READ_ONCE(ns->revision);
435 
436                                         if (!aa_get_profile_not0(profile))
437                                                 goto restart;
438                                         rcu_read_unlock();
439                                         ret = aa_xattrs_match(bprm, profile,
440                                                               state);
441                                         rcu_read_lock();
442                                         aa_put_profile(profile);
443                                         if (rev !=
444                                             READ_ONCE(ns->revision))
445                                                 /* policy changed */
446                                                 goto restart;
447                                         /*
448                                          * Fail matching if the xattrs don't
449                                          * match
450                                          */
451                                         if (ret < 0)
452                                                 continue;
453                                 }
454                                 /*
455                                  * TODO: allow for more flexible best match
456                                  *
457                                  * The new match isn't more specific
458                                  * than the current best match
459                                  */
460                                 if (count == candidate_len &&
461                                     ret <= candidate_xattrs) {
462                                         /* Match is equivalent, so conflict */
463                                         if (ret == candidate_xattrs)
464                                                 conflict = true;
465                                         continue;
466                                 }
467 
468                                 /* Either the same length with more matching
469                                  * xattrs, or a longer match
470                                  */
471                                 candidate = profile;
472                                 candidate_len = max(count, attach->xmatch_len);
473                                 candidate_xattrs = ret;
474                                 conflict = false;
475                         }
476                 } else if (!strcmp(profile->base.name, name)) {
477                         /*
478                          * old exact non-re match, without conditionals such
479                          * as xattrs. no more searching required
480                          */
481                         candidate = profile;
482                         goto out;
483                 }
484         }
485 
486         if (!candidate || conflict) {
487                 if (conflict)
488                         *info = "conflicting profile attachments";
489                 rcu_read_unlock();
490                 return NULL;
491         }
492 
493 out:
494         candidate = aa_get_newest_profile(candidate);
495         rcu_read_unlock();
496 
497         return &candidate->label;
498 }
499 
500 static const char *next_name(int xtype, const char *name)
501 {
502         return NULL;
503 }
504 
505 /**
506  * x_table_lookup - lookup an x transition name via transition table
507  * @profile: current profile (NOT NULL)
508  * @xindex: index into x transition table
509  * @name: returns: name tested to find label (NOT NULL)
510  *
511  * Returns: refcounted label, or NULL on failure (MAYBE NULL)
512  */
513 struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
514                                 const char **name)
515 {
516         struct aa_ruleset *rules = list_first_entry(&profile->rules,
517                                                     typeof(*rules), list);
518         struct aa_label *label = NULL;
519         u32 xtype = xindex & AA_X_TYPE_MASK;
520         int index = xindex & AA_X_INDEX_MASK;
521 
522         AA_BUG(!name);
523 
524         /* index is guaranteed to be in range, validated at load time */
525         /* TODO: move lookup parsing to unpack time so this is a straight
526          *       index into the resultant label
527          */
528         for (*name = rules->file->trans.table[index]; !label && *name;
529              *name = next_name(xtype, *name)) {
530                 if (xindex & AA_X_CHILD) {
531                         struct aa_profile *new_profile;
532                         /* release by caller */
533                         new_profile = aa_find_child(profile, *name);
534                         if (new_profile)
535                                 label = &new_profile->label;
536                         continue;
537                 }
538                 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
539                                        true, false);
540                 if (IS_ERR(label))
541                         label = NULL;
542         }
543 
544         /* released by caller */
545 
546         return label;
547 }
548 
549 /**
550  * x_to_label - get target label for a given xindex
551  * @profile: current profile  (NOT NULL)
552  * @bprm: binprm structure of transitioning task
553  * @name: name to lookup (NOT NULL)
554  * @xindex: index into x transition table
555  * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
556  * @info: info message if there was an error (NOT NULL)
557  *
558  * find label for a transition index
559  *
560  * Returns: refcounted label or NULL if not found available
561  */
562 static struct aa_label *x_to_label(struct aa_profile *profile,
563                                    const struct linux_binprm *bprm,
564                                    const char *name, u32 xindex,
565                                    const char **lookupname,
566                                    const char **info)
567 {
568         struct aa_ruleset *rules = list_first_entry(&profile->rules,
569                                                     typeof(*rules), list);
570         struct aa_label *new = NULL;
571         struct aa_ns *ns = profile->ns;
572         u32 xtype = xindex & AA_X_TYPE_MASK;
573         const char *stack = NULL;
574 
575         switch (xtype) {
576         case AA_X_NONE:
577                 /* fail exec unless ix || ux fallback - handled by caller */
578                 *lookupname = NULL;
579                 break;
580         case AA_X_TABLE:
581                 /* TODO: fix when perm mapping done at unload */
582                 stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
583                 if (*stack != '&') {
584                         /* released by caller */
585                         new = x_table_lookup(profile, xindex, lookupname);
586                         stack = NULL;
587                         break;
588                 }
589                 fallthrough;    /* to X_NAME */
590         case AA_X_NAME:
591                 if (xindex & AA_X_CHILD)
592                         /* released by caller */
593                         new = find_attach(bprm, ns, &profile->base.profiles,
594                                           name, info);
595                 else
596                         /* released by caller */
597                         new = find_attach(bprm, ns, &ns->base.profiles,
598                                           name, info);
599                 *lookupname = name;
600                 break;
601         }
602 
603         if (!new) {
604                 if (xindex & AA_X_INHERIT) {
605                         /* (p|c|n)ix - don't change profile but do
606                          * use the newest version
607                          */
608                         *info = "ix fallback";
609                         /* no profile && no error */
610                         new = aa_get_newest_label(&profile->label);
611                 } else if (xindex & AA_X_UNCONFINED) {
612                         new = aa_get_newest_label(ns_unconfined(profile->ns));
613                         *info = "ux fallback";
614                 }
615         }
616 
617         if (new && stack) {
618                 /* base the stack on post domain transition */
619                 struct aa_label *base = new;
620 
621                 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
622                 if (IS_ERR(new))
623                         new = NULL;
624                 aa_put_label(base);
625         }
626 
627         /* released by caller */
628         return new;
629 }
630 
631 static struct aa_label *profile_transition(const struct cred *subj_cred,
632                                            struct aa_profile *profile,
633                                            const struct linux_binprm *bprm,
634                                            char *buffer, struct path_cond *cond,
635                                            bool *secure_exec)
636 {
637         struct aa_ruleset *rules = list_first_entry(&profile->rules,
638                                                     typeof(*rules), list);
639         struct aa_label *new = NULL;
640         const char *info = NULL, *name = NULL, *target = NULL;
641         aa_state_t state = rules->file->start[AA_CLASS_FILE];
642         struct aa_perms perms = {};
643         bool nonewprivs = false;
644         int error = 0;
645 
646         AA_BUG(!profile);
647         AA_BUG(!bprm);
648         AA_BUG(!buffer);
649 
650         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
651                              &name, &info, profile->disconnected);
652         if (error) {
653                 if (profile_unconfined(profile) ||
654                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
655                         AA_DEBUG("name lookup ix on error");
656                         error = 0;
657                         new = aa_get_newest_label(&profile->label);
658                 }
659                 name = bprm->filename;
660                 goto audit;
661         }
662 
663         if (profile_unconfined(profile)) {
664                 new = find_attach(bprm, profile->ns,
665                                   &profile->ns->base.profiles, name, &info);
666                 if (new) {
667                         AA_DEBUG("unconfined attached to new label");
668                         return new;
669                 }
670                 AA_DEBUG("unconfined exec no attachment");
671                 return aa_get_newest_label(&profile->label);
672         }
673 
674         /* find exec permissions for name */
675         state = aa_str_perms(rules->file, state, name, cond, &perms);
676         if (perms.allow & MAY_EXEC) {
677                 /* exec permission determine how to transition */
678                 new = x_to_label(profile, bprm, name, perms.xindex, &target,
679                                  &info);
680                 if (new && new->proxy == profile->label.proxy && info) {
681                         /* hack ix fallback - improve how this is detected */
682                         goto audit;
683                 } else if (!new) {
684                         error = -EACCES;
685                         info = "profile transition not found";
686                         /* remove MAY_EXEC to audit as failure */
687                         perms.allow &= ~MAY_EXEC;
688                 }
689         } else if (COMPLAIN_MODE(profile)) {
690                 /* no exec permission - learning mode */
691                 struct aa_profile *new_profile = NULL;
692 
693                 new_profile = aa_new_learning_profile(profile, false, name,
694                                                       GFP_KERNEL);
695                 if (!new_profile) {
696                         error = -ENOMEM;
697                         info = "could not create null profile";
698                 } else {
699                         error = -EACCES;
700                         new = &new_profile->label;
701                 }
702                 perms.xindex |= AA_X_UNSAFE;
703         } else
704                 /* fail exec */
705                 error = -EACCES;
706 
707         if (!new)
708                 goto audit;
709 
710 
711         if (!(perms.xindex & AA_X_UNSAFE)) {
712                 if (DEBUG_ON) {
713                         dbg_printk("apparmor: scrubbing environment variables"
714                                    " for %s profile=", name);
715                         aa_label_printk(new, GFP_KERNEL);
716                         dbg_printk("\n");
717                 }
718                 *secure_exec = true;
719         }
720 
721 audit:
722         aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
723                       target, new,
724                       cond->uid, info, error);
725         if (!new || nonewprivs) {
726                 aa_put_label(new);
727                 return ERR_PTR(error);
728         }
729 
730         return new;
731 }
732 
733 static int profile_onexec(const struct cred *subj_cred,
734                           struct aa_profile *profile, struct aa_label *onexec,
735                           bool stack, const struct linux_binprm *bprm,
736                           char *buffer, struct path_cond *cond,
737                           bool *secure_exec)
738 {
739         struct aa_ruleset *rules = list_first_entry(&profile->rules,
740                                                     typeof(*rules), list);
741         aa_state_t state = rules->file->start[AA_CLASS_FILE];
742         struct aa_perms perms = {};
743         const char *xname = NULL, *info = "change_profile onexec";
744         int error = -EACCES;
745 
746         AA_BUG(!profile);
747         AA_BUG(!onexec);
748         AA_BUG(!bprm);
749         AA_BUG(!buffer);
750 
751         if (profile_unconfined(profile)) {
752                 /* change_profile on exec already granted */
753                 /*
754                  * NOTE: Domain transitions from unconfined are allowed
755                  * even when no_new_privs is set because this aways results
756                  * in a further reduction of permissions.
757                  */
758                 return 0;
759         }
760 
761         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
762                              &xname, &info, profile->disconnected);
763         if (error) {
764                 if (profile_unconfined(profile) ||
765                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
766                         AA_DEBUG("name lookup ix on error");
767                         error = 0;
768                 }
769                 xname = bprm->filename;
770                 goto audit;
771         }
772 
773         /* find exec permissions for name */
774         state = aa_str_perms(rules->file, state, xname, cond, &perms);
775         if (!(perms.allow & AA_MAY_ONEXEC)) {
776                 info = "no change_onexec valid for executable";
777                 goto audit;
778         }
779         /* test if this exec can be paired with change_profile onexec.
780          * onexec permission is linked to exec with a standard pairing
781          * exec\0change_profile
782          */
783         state = aa_dfa_null_transition(rules->file->dfa, state);
784         error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
785                                      state, &perms);
786         if (error) {
787                 perms.allow &= ~AA_MAY_ONEXEC;
788                 goto audit;
789         }
790 
791         if (!(perms.xindex & AA_X_UNSAFE)) {
792                 if (DEBUG_ON) {
793                         dbg_printk("apparmor: scrubbing environment "
794                                    "variables for %s label=", xname);
795                         aa_label_printk(onexec, GFP_KERNEL);
796                         dbg_printk("\n");
797                 }
798                 *secure_exec = true;
799         }
800 
801 audit:
802         return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
803                              AA_MAY_ONEXEC, xname,
804                              NULL, onexec, cond->uid, info, error);
805 }
806 
807 /* ensure none ns domain transitions are correctly applied with onexec */
808 
809 static struct aa_label *handle_onexec(const struct cred *subj_cred,
810                                       struct aa_label *label,
811                                       struct aa_label *onexec, bool stack,
812                                       const struct linux_binprm *bprm,
813                                       char *buffer, struct path_cond *cond,
814                                       bool *unsafe)
815 {
816         struct aa_profile *profile;
817         struct aa_label *new;
818         int error;
819 
820         AA_BUG(!label);
821         AA_BUG(!onexec);
822         AA_BUG(!bprm);
823         AA_BUG(!buffer);
824 
825         if (!stack) {
826                 error = fn_for_each_in_ns(label, profile,
827                                 profile_onexec(subj_cred, profile, onexec, stack,
828                                                bprm, buffer, cond, unsafe));
829                 if (error)
830                         return ERR_PTR(error);
831                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
832                                 aa_get_newest_label(onexec),
833                                 profile_transition(subj_cred, profile, bprm,
834                                                    buffer,
835                                                    cond, unsafe));
836 
837         } else {
838                 /* TODO: determine how much we want to loosen this */
839                 error = fn_for_each_in_ns(label, profile,
840                                 profile_onexec(subj_cred, profile, onexec, stack, bprm,
841                                                buffer, cond, unsafe));
842                 if (error)
843                         return ERR_PTR(error);
844                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
845                                 aa_label_merge(&profile->label, onexec,
846                                                GFP_KERNEL),
847                                 profile_transition(subj_cred, profile, bprm,
848                                                    buffer,
849                                                    cond, unsafe));
850         }
851 
852         if (new)
853                 return new;
854 
855         /* TODO: get rid of GLOBAL_ROOT_UID */
856         error = fn_for_each_in_ns(label, profile,
857                         aa_audit_file(subj_cred, profile, &nullperms,
858                                       OP_CHANGE_ONEXEC,
859                                       AA_MAY_ONEXEC, bprm->filename, NULL,
860                                       onexec, GLOBAL_ROOT_UID,
861                                       "failed to build target label", -ENOMEM));
862         return ERR_PTR(error);
863 }
864 
865 /**
866  * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
867  * @bprm: binprm for the exec  (NOT NULL)
868  *
869  * Returns: %0 or error on failure
870  *
871  * TODO: once the other paths are done see if we can't refactor into a fn
872  */
873 int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
874 {
875         struct aa_task_ctx *ctx;
876         struct aa_label *label, *new = NULL;
877         const struct cred *subj_cred;
878         struct aa_profile *profile;
879         char *buffer = NULL;
880         const char *info = NULL;
881         int error = 0;
882         bool unsafe = false;
883         vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
884                                             file_inode(bprm->file));
885         struct path_cond cond = {
886                 vfsuid_into_kuid(vfsuid),
887                 file_inode(bprm->file)->i_mode
888         };
889 
890         subj_cred = current_cred();
891         ctx = task_ctx(current);
892         AA_BUG(!cred_label(bprm->cred));
893         AA_BUG(!ctx);
894 
895         label = aa_get_newest_label(cred_label(bprm->cred));
896 
897         /*
898          * Detect no new privs being set, and store the label it
899          * occurred under. Ideally this would happen when nnp
900          * is set but there isn't a good way to do that yet.
901          *
902          * Testing for unconfined must be done before the subset test
903          */
904         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
905             !ctx->nnp)
906                 ctx->nnp = aa_get_label(label);
907 
908         /* buffer freed below, name is pointer into buffer */
909         buffer = aa_get_buffer(false);
910         if (!buffer) {
911                 error = -ENOMEM;
912                 goto done;
913         }
914 
915         /* Test for onexec first as onexec override other x transitions. */
916         if (ctx->onexec)
917                 new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
918                                     bprm, buffer, &cond, &unsafe);
919         else
920                 new = fn_label_build(label, profile, GFP_KERNEL,
921                                 profile_transition(subj_cred, profile, bprm,
922                                                    buffer,
923                                                    &cond, &unsafe));
924 
925         AA_BUG(!new);
926         if (IS_ERR(new)) {
927                 error = PTR_ERR(new);
928                 goto done;
929         } else if (!new) {
930                 error = -ENOMEM;
931                 goto done;
932         }
933 
934         /* Policy has specified a domain transitions. If no_new_privs and
935          * confined ensure the transition is to confinement that is subset
936          * of the confinement when the task entered no new privs.
937          *
938          * NOTE: Domain transitions from unconfined and to stacked
939          * subsets are allowed even when no_new_privs is set because this
940          * aways results in a further reduction of permissions.
941          */
942         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
943             !unconfined(label) &&
944             !aa_label_is_unconfined_subset(new, ctx->nnp)) {
945                 error = -EPERM;
946                 info = "no new privs";
947                 goto audit;
948         }
949 
950         if (bprm->unsafe & LSM_UNSAFE_SHARE) {
951                 /* FIXME: currently don't mediate shared state */
952                 ;
953         }
954 
955         if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
956                 /* TODO: test needs to be profile of label to new */
957                 error = may_change_ptraced_domain(bprm->cred, new, &info);
958                 if (error)
959                         goto audit;
960         }
961 
962         if (unsafe) {
963                 if (DEBUG_ON) {
964                         dbg_printk("scrubbing environment variables for %s "
965                                    "label=", bprm->filename);
966                         aa_label_printk(new, GFP_KERNEL);
967                         dbg_printk("\n");
968                 }
969                 bprm->secureexec = 1;
970         }
971 
972         if (label->proxy != new->proxy) {
973                 /* when transitioning clear unsafe personality bits */
974                 if (DEBUG_ON) {
975                         dbg_printk("apparmor: clearing unsafe personality "
976                                    "bits. %s label=", bprm->filename);
977                         aa_label_printk(new, GFP_KERNEL);
978                         dbg_printk("\n");
979                 }
980                 bprm->per_clear |= PER_CLEAR_ON_SETID;
981         }
982         aa_put_label(cred_label(bprm->cred));
983         /* transfer reference, released when cred is freed */
984         set_cred_label(bprm->cred, new);
985 
986 done:
987         aa_put_label(label);
988         aa_put_buffer(buffer);
989 
990         return error;
991 
992 audit:
993         error = fn_for_each(label, profile,
994                         aa_audit_file(current_cred(), profile, &nullperms,
995                                       OP_EXEC, MAY_EXEC,
996                                       bprm->filename, NULL, new,
997                                       vfsuid_into_kuid(vfsuid), info, error));
998         aa_put_label(new);
999         goto done;
1000 }
1001 
1002 /*
1003  * Functions for self directed profile change
1004  */
1005 
1006 
1007 /* helper fn for change_hat
1008  *
1009  * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
1010  */
1011 static struct aa_label *build_change_hat(const struct cred *subj_cred,
1012                                          struct aa_profile *profile,
1013                                          const char *name, bool sibling)
1014 {
1015         struct aa_profile *root, *hat = NULL;
1016         const char *info = NULL;
1017         int error = 0;
1018 
1019         if (sibling && PROFILE_IS_HAT(profile)) {
1020                 root = aa_get_profile_rcu(&profile->parent);
1021         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1022                 root = aa_get_profile(profile);
1023         } else {
1024                 info = "conflicting target types";
1025                 error = -EPERM;
1026                 goto audit;
1027         }
1028 
1029         hat = aa_find_child(root, name);
1030         if (!hat) {
1031                 error = -ENOENT;
1032                 if (COMPLAIN_MODE(profile)) {
1033                         hat = aa_new_learning_profile(profile, true, name,
1034                                                       GFP_KERNEL);
1035                         if (!hat) {
1036                                 info = "failed null profile create";
1037                                 error = -ENOMEM;
1038                         }
1039                 }
1040         }
1041         aa_put_profile(root);
1042 
1043 audit:
1044         aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1045                       AA_MAY_CHANGEHAT,
1046                       name, hat ? hat->base.hname : NULL,
1047                       hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1048                       error);
1049         if (!hat || (error && error != -ENOENT))
1050                 return ERR_PTR(error);
1051         /* if hat && error - complain mode, already audited and we adjust for
1052          * complain mode allow by returning hat->label
1053          */
1054         return &hat->label;
1055 }
1056 
1057 /* helper fn for changing into a hat
1058  *
1059  * Returns: label for hat transition or ERR_PTR. Does not return NULL
1060  */
1061 static struct aa_label *change_hat(const struct cred *subj_cred,
1062                                    struct aa_label *label, const char *hats[],
1063                                    int count, int flags)
1064 {
1065         struct aa_profile *profile, *root, *hat = NULL;
1066         struct aa_label *new;
1067         struct label_it it;
1068         bool sibling = false;
1069         const char *name, *info = NULL;
1070         int i, error;
1071 
1072         AA_BUG(!label);
1073         AA_BUG(!hats);
1074         AA_BUG(count < 1);
1075 
1076         if (PROFILE_IS_HAT(labels_profile(label)))
1077                 sibling = true;
1078 
1079         /*find first matching hat */
1080         for (i = 0; i < count && !hat; i++) {
1081                 name = hats[i];
1082                 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1083                         if (sibling && PROFILE_IS_HAT(profile)) {
1084                                 root = aa_get_profile_rcu(&profile->parent);
1085                         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1086                                 root = aa_get_profile(profile);
1087                         } else {        /* conflicting change type */
1088                                 info = "conflicting targets types";
1089                                 error = -EPERM;
1090                                 goto fail;
1091                         }
1092                         hat = aa_find_child(root, name);
1093                         aa_put_profile(root);
1094                         if (!hat) {
1095                                 if (!COMPLAIN_MODE(profile))
1096                                         goto outer_continue;
1097                                 /* complain mode succeed as if hat */
1098                         } else if (!PROFILE_IS_HAT(hat)) {
1099                                 info = "target not hat";
1100                                 error = -EPERM;
1101                                 aa_put_profile(hat);
1102                                 goto fail;
1103                         }
1104                         aa_put_profile(hat);
1105                 }
1106                 /* found a hat for all profiles in ns */
1107                 goto build;
1108 outer_continue:
1109         ;
1110         }
1111         /* no hats that match, find appropriate error
1112          *
1113          * In complain mode audit of the failure is based off of the first
1114          * hat supplied.  This is done due how userspace interacts with
1115          * change_hat.
1116          */
1117         name = NULL;
1118         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1119                 if (!list_empty(&profile->base.profiles)) {
1120                         info = "hat not found";
1121                         error = -ENOENT;
1122                         goto fail;
1123                 }
1124         }
1125         info = "no hats defined";
1126         error = -ECHILD;
1127 
1128 fail:
1129         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1130                 /*
1131                  * no target as it has failed to be found or built
1132                  *
1133                  * change_hat uses probing and should not log failures
1134                  * related to missing hats
1135                  */
1136                 /* TODO: get rid of GLOBAL_ROOT_UID */
1137                 if (count > 1 || COMPLAIN_MODE(profile)) {
1138                         aa_audit_file(subj_cred, profile, &nullperms,
1139                                       OP_CHANGE_HAT,
1140                                       AA_MAY_CHANGEHAT, name, NULL, NULL,
1141                                       GLOBAL_ROOT_UID, info, error);
1142                 }
1143         }
1144         return ERR_PTR(error);
1145 
1146 build:
1147         new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1148                                    build_change_hat(subj_cred, profile, name,
1149                                                     sibling),
1150                                    aa_get_label(&profile->label));
1151         if (!new) {
1152                 info = "label build failed";
1153                 error = -ENOMEM;
1154                 goto fail;
1155         } /* else if (IS_ERR) build_change_hat has logged error so return new */
1156 
1157         return new;
1158 }
1159 
1160 /**
1161  * aa_change_hat - change hat to/from subprofile
1162  * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1163  * @count: number of hat names in @hats
1164  * @token: magic value to validate the hat change
1165  * @flags: flags affecting behavior of the change
1166  *
1167  * Returns %0 on success, error otherwise.
1168  *
1169  * Change to the first profile specified in @hats that exists, and store
1170  * the @hat_magic in the current task context.  If the count == 0 and the
1171  * @token matches that stored in the current task context, return to the
1172  * top level profile.
1173  *
1174  * change_hat only applies to profiles in the current ns, and each profile
1175  * in the ns must make the same transition otherwise change_hat will fail.
1176  */
1177 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1178 {
1179         const struct cred *subj_cred;
1180         struct aa_task_ctx *ctx = task_ctx(current);
1181         struct aa_label *label, *previous, *new = NULL, *target = NULL;
1182         struct aa_profile *profile;
1183         struct aa_perms perms = {};
1184         const char *info = NULL;
1185         int error = 0;
1186 
1187         /* released below */
1188         subj_cred = get_current_cred();
1189         label = aa_get_newest_cred_label(subj_cred);
1190         previous = aa_get_newest_label(ctx->previous);
1191 
1192         /*
1193          * Detect no new privs being set, and store the label it
1194          * occurred under. Ideally this would happen when nnp
1195          * is set but there isn't a good way to do that yet.
1196          *
1197          * Testing for unconfined must be done before the subset test
1198          */
1199         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1200                 ctx->nnp = aa_get_label(label);
1201 
1202         if (unconfined(label)) {
1203                 info = "unconfined can not change_hat";
1204                 error = -EPERM;
1205                 goto fail;
1206         }
1207 
1208         if (count) {
1209                 new = change_hat(subj_cred, label, hats, count, flags);
1210                 AA_BUG(!new);
1211                 if (IS_ERR(new)) {
1212                         error = PTR_ERR(new);
1213                         new = NULL;
1214                         /* already audited */
1215                         goto out;
1216                 }
1217 
1218                 /* target cred is the same as current except new label */
1219                 error = may_change_ptraced_domain(subj_cred, new, &info);
1220                 if (error)
1221                         goto fail;
1222 
1223                 /*
1224                  * no new privs prevents domain transitions that would
1225                  * reduce restrictions.
1226                  */
1227                 if (task_no_new_privs(current) && !unconfined(label) &&
1228                     !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1229                         /* not an apparmor denial per se, so don't log it */
1230                         AA_DEBUG("no_new_privs - change_hat denied");
1231                         error = -EPERM;
1232                         goto out;
1233                 }
1234 
1235                 if (flags & AA_CHANGE_TEST)
1236                         goto out;
1237 
1238                 target = new;
1239                 error = aa_set_current_hat(new, token);
1240                 if (error == -EACCES)
1241                         /* kill task in case of brute force attacks */
1242                         goto kill;
1243         } else if (previous && !(flags & AA_CHANGE_TEST)) {
1244                 /*
1245                  * no new privs prevents domain transitions that would
1246                  * reduce restrictions.
1247                  */
1248                 if (task_no_new_privs(current) && !unconfined(label) &&
1249                     !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1250                         /* not an apparmor denial per se, so don't log it */
1251                         AA_DEBUG("no_new_privs - change_hat denied");
1252                         error = -EPERM;
1253                         goto out;
1254                 }
1255 
1256                 /* Return to saved label.  Kill task if restore fails
1257                  * to avoid brute force attacks
1258                  */
1259                 target = previous;
1260                 error = aa_restore_previous_label(token);
1261                 if (error) {
1262                         if (error == -EACCES)
1263                                 goto kill;
1264                         goto fail;
1265                 }
1266         } /* else ignore @flags && restores when there is no saved profile */
1267 
1268 out:
1269         aa_put_label(new);
1270         aa_put_label(previous);
1271         aa_put_label(label);
1272         put_cred(subj_cred);
1273 
1274         return error;
1275 
1276 kill:
1277         info = "failed token match";
1278         perms.kill = AA_MAY_CHANGEHAT;
1279 
1280 fail:
1281         fn_for_each_in_ns(label, profile,
1282                 aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1283                               AA_MAY_CHANGEHAT, NULL, NULL, target,
1284                               GLOBAL_ROOT_UID, info, error));
1285 
1286         goto out;
1287 }
1288 
1289 
1290 static int change_profile_perms_wrapper(const char *op, const char *name,
1291                                         const struct cred *subj_cred,
1292                                         struct aa_profile *profile,
1293                                         struct aa_label *target, bool stack,
1294                                         u32 request, struct aa_perms *perms)
1295 {
1296         struct aa_ruleset *rules = list_first_entry(&profile->rules,
1297                                                     typeof(*rules), list);
1298         const char *info = NULL;
1299         int error = 0;
1300 
1301         if (!error)
1302                 error = change_profile_perms(profile, target, stack, request,
1303                                              rules->file->start[AA_CLASS_FILE],
1304                                              perms);
1305         if (error)
1306                 error = aa_audit_file(subj_cred, profile, perms, op, request,
1307                                       name,
1308                                       NULL, target, GLOBAL_ROOT_UID, info,
1309                                       error);
1310 
1311         return error;
1312 }
1313 
1314 static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
1315 
1316 /**
1317  * aa_change_profile - perform a one-way profile transition
1318  * @fqname: name of profile may include namespace (NOT NULL)
1319  * @flags: flags affecting change behavior
1320  *
1321  * Change to new profile @name.  Unlike with hats, there is no way
1322  * to change back.  If @name isn't specified the current profile name is
1323  * used.
1324  * If @onexec then the transition is delayed until
1325  * the next exec.
1326  *
1327  * Returns %0 on success, error otherwise.
1328  */
1329 int aa_change_profile(const char *fqname, int flags)
1330 {
1331         struct aa_label *label, *new = NULL, *target = NULL;
1332         struct aa_profile *profile;
1333         struct aa_perms perms = {};
1334         const char *info = NULL;
1335         const char *auditname = fqname;         /* retain leading & if stack */
1336         bool stack = flags & AA_CHANGE_STACK;
1337         struct aa_task_ctx *ctx = task_ctx(current);
1338         const struct cred *subj_cred = get_current_cred();
1339         int error = 0;
1340         char *op;
1341         u32 request;
1342 
1343         label = aa_get_current_label();
1344 
1345         /*
1346          * Detect no new privs being set, and store the label it
1347          * occurred under. Ideally this would happen when nnp
1348          * is set but there isn't a good way to do that yet.
1349          *
1350          * Testing for unconfined must be done before the subset test
1351          */
1352         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1353                 ctx->nnp = aa_get_label(label);
1354 
1355         if (!fqname || !*fqname) {
1356                 aa_put_label(label);
1357                 AA_DEBUG("no profile name");
1358                 return -EINVAL;
1359         }
1360 
1361         if (flags & AA_CHANGE_ONEXEC) {
1362                 request = AA_MAY_ONEXEC;
1363                 if (stack)
1364                         op = OP_STACK_ONEXEC;
1365                 else
1366                         op = OP_CHANGE_ONEXEC;
1367         } else {
1368                 request = AA_MAY_CHANGE_PROFILE;
1369                 if (stack)
1370                         op = OP_STACK;
1371                 else
1372                         op = OP_CHANGE_PROFILE;
1373         }
1374 
1375         /* This should move to a per profile test. Requires pushing build
1376          * into callback
1377          */
1378         if (!stack && unconfined(label) &&
1379             label == &labels_ns(label)->unconfined->label &&
1380             aa_unprivileged_unconfined_restricted &&
1381             /* TODO: refactor so this check is a fn */
1382             cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
1383                         CAP_OPT_NOAUDIT)) {
1384                 /* regardless of the request in this case apparmor
1385                  * stacks against unconfined so admin set policy can't be
1386                  * by-passed
1387                  */
1388                 stack = true;
1389                 perms.audit = request;
1390                 (void) fn_for_each_in_ns(label, profile,
1391                                 aa_audit_file(subj_cred, profile, &perms, op,
1392                                               request, auditname, NULL, target,
1393                                               GLOBAL_ROOT_UID, stack_msg, 0));
1394                 perms.audit = 0;
1395         }
1396 
1397         if (*fqname == '&') {
1398                 stack = true;
1399                 /* don't have label_parse() do stacking */
1400                 fqname++;
1401         }
1402         target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1403         if (IS_ERR(target)) {
1404                 struct aa_profile *tprofile;
1405 
1406                 info = "label not found";
1407                 error = PTR_ERR(target);
1408                 target = NULL;
1409                 /*
1410                  * TODO: fixme using labels_profile is not right - do profile
1411                  * per complain profile
1412                  */
1413                 if ((flags & AA_CHANGE_TEST) ||
1414                     !COMPLAIN_MODE(labels_profile(label)))
1415                         goto audit;
1416                 /* released below */
1417                 tprofile = aa_new_learning_profile(labels_profile(label), false,
1418                                                    fqname, GFP_KERNEL);
1419                 if (!tprofile) {
1420                         info = "failed null profile create";
1421                         error = -ENOMEM;
1422                         goto audit;
1423                 }
1424                 target = &tprofile->label;
1425                 goto check;
1426         }
1427 
1428         /*
1429          * self directed transitions only apply to current policy ns
1430          * TODO: currently requiring perms for stacking and straight change
1431          *       stacking doesn't strictly need this. Determine how much
1432          *       we want to loosen this restriction for stacking
1433          *
1434          * if (!stack) {
1435          */
1436         error = fn_for_each_in_ns(label, profile,
1437                         change_profile_perms_wrapper(op, auditname,
1438                                                      subj_cred,
1439                                                      profile, target, stack,
1440                                                      request, &perms));
1441         if (error)
1442                 /* auditing done in change_profile_perms_wrapper */
1443                 goto out;
1444 
1445         /* } */
1446 
1447 check:
1448         /* check if tracing task is allowed to trace target domain */
1449         error = may_change_ptraced_domain(subj_cred, target, &info);
1450         if (error && !fn_for_each_in_ns(label, profile,
1451                                         COMPLAIN_MODE(profile)))
1452                 goto audit;
1453 
1454         /* TODO: add permission check to allow this
1455          * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1456          *      info = "not a single threaded task";
1457          *      error = -EACCES;
1458          *      goto audit;
1459          * }
1460          */
1461         if (flags & AA_CHANGE_TEST)
1462                 goto out;
1463 
1464         /* stacking is always a subset, so only check the nonstack case */
1465         if (!stack) {
1466                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1467                                            aa_get_label(target),
1468                                            aa_get_label(&profile->label));
1469                 /*
1470                  * no new privs prevents domain transitions that would
1471                  * reduce restrictions.
1472                  */
1473                 if (task_no_new_privs(current) && !unconfined(label) &&
1474                     !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1475                         /* not an apparmor denial per se, so don't log it */
1476                         AA_DEBUG("no_new_privs - change_hat denied");
1477                         error = -EPERM;
1478                         goto out;
1479                 }
1480         }
1481 
1482         if (!(flags & AA_CHANGE_ONEXEC)) {
1483                 /* only transition profiles in the current ns */
1484                 if (stack)
1485                         new = aa_label_merge(label, target, GFP_KERNEL);
1486                 if (IS_ERR_OR_NULL(new)) {
1487                         info = "failed to build target label";
1488                         if (!new)
1489                                 error = -ENOMEM;
1490                         else
1491                                 error = PTR_ERR(new);
1492                         new = NULL;
1493                         perms.allow = 0;
1494                         goto audit;
1495                 }
1496                 error = aa_replace_current_label(new);
1497         } else {
1498                 if (new) {
1499                         aa_put_label(new);
1500                         new = NULL;
1501                 }
1502 
1503                 /* full transition will be built in exec path */
1504                 aa_set_current_onexec(target, stack);
1505         }
1506 
1507 audit:
1508         error = fn_for_each_in_ns(label, profile,
1509                         aa_audit_file(subj_cred,
1510                                       profile, &perms, op, request, auditname,
1511                                       NULL, new ? new : target,
1512                                       GLOBAL_ROOT_UID, info, error));
1513 
1514 out:
1515         aa_put_label(new);
1516         aa_put_label(target);
1517         aa_put_label(label);
1518         put_cred(subj_cred);
1519 
1520         return error;
1521 }
1522 

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