security/apparmor/domain.c

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