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
 321         /* transition from exec match to xattr set */
 322         state = aa_dfa_null_transition(profile->xmatch, state);
 323
 324         d = bprm->file->f_path.dentry;
 325
 326         for (i = 0; i < profile->xattr_count; i++) {
 327                 size = vfs_getxattr_alloc(d, profile->xattrs[i], &value,
 328                                           value_size, GFP_KERNEL);
 329                 if (size >= 0) {
 330                         u32 perm;
 331
 332                         /* Check the xattr value, not just presence */
 333                         state = aa_dfa_match_len(profile->xmatch, state, value,
 334                                                  size);
 335                         perm = dfa_user_allow(profile->xmatch, state);
 336                         if (!(perm & MAY_EXEC)) {
 337                                 ret = -EINVAL;
 338                                 goto out;
 339                         }
 340                 }
 341                 /* transition to next element */
 342                 state = aa_dfa_null_transition(profile->xmatch, state);
 343                 if (size < 0) {
 344                         /*
 345                          * No xattr match, so verify if transition to
 346                          * next element was valid. IFF so the xattr
 347                          * was optional.
 348                          */
 349                         if (!state) {
 350                                 ret = -EINVAL;
 351                                 goto out;
 352                         }
 353                         /* don't count missing optional xattr as matched */
 354                         ret--;
 355                 }
 356         }
 357
 358 out:
 359         kfree(value);
 360         return ret;
 361 }
 362
 363 /**
 364  * __attach_match_ - find an attachment match
 365  * @bprm - binprm structure of transitioning task
 366  * @name - to match against  (NOT NULL)
 367  * @head - profile list to walk  (NOT NULL)
 368  * @info - info message if there was an error (NOT NULL)
 369  *
 370  * Do a linear search on the profiles in the list.  There is a matching
 371  * preference where an exact match is preferred over a name which uses
 372  * expressions to match, and matching expressions with the greatest
 373  * xmatch_len are preferred.
 374  *
 375  * Requires: @head not be shared or have appropriate locks held
 376  *
 377  * Returns: profile or NULL if no match found
 378  */
 379 static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
 380                                          const char *name,
 381                                          struct list_head *head,
 382                                          const char **info)
 383 {
 384         int candidate_len = 0, candidate_xattrs = 0;
 385         bool conflict = false;
 386         struct aa_profile *profile, *candidate = NULL;
 387
 388         AA_BUG(!name);
 389         AA_BUG(!head);
 390
 391         list_for_each_entry_rcu(profile, head, base.list) {
 392                 if (profile->label.flags & FLAG_NULL &&
 393                     &profile->label == ns_unconfined(profile->ns))
 394                         continue;
 395
 396                 /* Find the "best" matching profile. Profiles must
 397                  * match the path and extended attributes (if any)
 398                  * associated with the file. A more specific path
 399                  * match will be preferred over a less specific one,
 400                  * and a match with more matching extended attributes
 401                  * will be preferred over one with fewer. If the best
 402                  * match has both the same level of path specificity
 403                  * and the same number of matching extended attributes
 404                  * as another profile, signal a conflict and refuse to
 405                  * match.
 406                  */
 407                 if (profile->xmatch) {
 408                         unsigned int state, count;
 409                         u32 perm;
 410
 411                         state = aa_dfa_leftmatch(profile->xmatch, DFA_START,
 412                                                  name, &count);
 413                         perm = dfa_user_allow(profile->xmatch, state);
 414                         /* any accepting state means a valid match. */
 415                         if (perm & MAY_EXEC) {
 416                                 int ret;
 417
 418                                 if (count < candidate_len)
 419                                         continue;
 420
 421                                 ret = aa_xattrs_match(bprm, profile, state);
 422                                 /* Fail matching if the xattrs don't match */
 423                                 if (ret < 0)
 424                                         continue;
 425
 426                                 /*
 427                                  * TODO: allow for more flexible best match
 428                                  *
 429                                  * The new match isn't more specific
 430                                  * than the current best match
 431                                  */
 432                                 if (count == candidate_len &&
 433                                     ret <= candidate_xattrs) {
 434                                         /* Match is equivalent, so conflict */
 435                                         if (ret == candidate_xattrs)
 436                                                 conflict = true;
 437                                         continue;
 438                                 }
 439
 440                                 /* Either the same length with more matching
 441                                  * xattrs, or a longer match
 442                                  */
 443                                 candidate = profile;
 444                                 candidate_len = profile->xmatch_len;
 445                                 candidate_xattrs = ret;
 446                                 conflict = false;
 447                         }
 448                 } else if (!strcmp(profile->base.name, name))
 449                         /*
 450                          * old exact non-re match, without conditionals such
 451                          * as xattrs. no more searching required
 452                          */
 453                         return profile;
 454         }
 455
 456         if (conflict) {
 457                 *info = "conflicting profile attachments";
 458                 return NULL;
 459         }
 460
 461         return candidate;
 462 }
 463
 464 /**
 465  * find_attach - do attachment search for unconfined processes
 466  * @bprm - binprm structure of transitioning task
 467  * @ns: the current namespace  (NOT NULL)
 468  * @list: list to search  (NOT NULL)
 469  * @name: the executable name to match against  (NOT NULL)
 470  * @info: info message if there was an error
 471  *
 472  * Returns: label or NULL if no match found
 473  */
 474 static struct aa_label *find_attach(const struct linux_binprm *bprm,
 475                                     struct aa_ns *ns, struct list_head *list,
 476                                     const char *name, const char **info)
 477 {
 478         struct aa_profile *profile;
 479
 480         rcu_read_lock();
 481         profile = aa_get_profile(__attach_match(bprm, name, list, info));
 482         rcu_read_unlock();
 483
 484         return profile ? &profile->label : NULL;
 485 }
 486
 487 static const char *next_name(int xtype, const char *name)
 488 {
 489         return NULL;
 490 }
 491
 492 /**
 493  * x_table_lookup - lookup an x transition name via transition table
 494  * @profile: current profile (NOT NULL)
 495  * @xindex: index into x transition table
 496  * @name: returns: name tested to find label (NOT NULL)
 497  *
 498  * Returns: refcounted label, or NULL on failure (MAYBE NULL)
 499  */
 500 struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
 501                                 const char **name)
 502 {
 503         struct aa_label *label = NULL;
 504         u32 xtype = xindex & AA_X_TYPE_MASK;
 505         int index = xindex & AA_X_INDEX_MASK;
 506
 507         AA_BUG(!name);
 508
 509         /* index is guaranteed to be in range, validated at load time */
 510         /* TODO: move lookup parsing to unpack time so this is a straight
 511          *       index into the resultant label
 512          */
 513         for (*name = profile->file.trans.table[index]; !label && *name;
 514              *name = next_name(xtype, *name)) {
 515                 if (xindex & AA_X_CHILD) {
 516                         struct aa_profile *new_profile;
 517                         /* release by caller */
 518                         new_profile = aa_find_child(profile, *name);
 519                         if (new_profile)
 520                                 label = &new_profile->label;
 521                         continue;
 522                 }
 523                 label = aa_label_parse(&profile->label, *name, GFP_ATOMIC,
 524                                        true, false);
 525                 if (IS_ERR(label))
 526                         label = NULL;
 527         }
 528
 529         /* released by caller */
 530
 531         return label;
 532 }
 533
 534 /**
 535  * x_to_label - get target label for a given xindex
 536  * @profile: current profile  (NOT NULL)
 537  * @bprm: binprm structure of transitioning task
 538  * @name: name to lookup (NOT NULL)
 539  * @xindex: index into x transition table
 540  * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
 541  *
 542  * find label for a transition index
 543  *
 544  * Returns: refcounted label or NULL if not found available
 545  */
 546 static struct aa_label *x_to_label(struct aa_profile *profile,
 547                                    const struct linux_binprm *bprm,
 548                                    const char *name, u32 xindex,
 549                                    const char **lookupname,
 550                                    const char **info)
 551 {
 552         struct aa_label *new = NULL;
 553         struct aa_ns *ns = profile->ns;
 554         u32 xtype = xindex & AA_X_TYPE_MASK;
 555         const char *stack = NULL;
 556
 557         switch (xtype) {
 558         case AA_X_NONE:
 559                 /* fail exec unless ix || ux fallback - handled by caller */
 560                 *lookupname = NULL;
 561                 break;
 562         case AA_X_TABLE:
 563                 /* TODO: fix when perm mapping done at unload */
 564                 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
 565                 if (*stack != '&') {
 566                         /* released by caller */
 567                         new = x_table_lookup(profile, xindex, lookupname);
 568                         stack = NULL;
 569                         break;
 570                 }
 571                 /* fall through - to X_NAME */
 572         case AA_X_NAME:
 573                 if (xindex & AA_X_CHILD)
 574                         /* released by caller */
 575                         new = find_attach(bprm, ns, &profile->base.profiles,
 576                                           name, info);
 577                 else
 578                         /* released by caller */
 579                         new = find_attach(bprm, ns, &ns->base.profiles,
 580                                           name, info);
 581                 *lookupname = name;
 582                 break;
 583         }
 584
 585         if (!new) {
 586                 if (xindex & AA_X_INHERIT) {
 587                         /* (p|c|n)ix - don't change profile but do
 588                          * use the newest version
 589                          */
 590                         *info = "ix fallback";
 591                         /* no profile && no error */
 592                         new = aa_get_newest_label(&profile->label);
 593                 } else if (xindex & AA_X_UNCONFINED) {
 594                         new = aa_get_newest_label(ns_unconfined(profile->ns));
 595                         *info = "ux fallback";
 596                 }
 597         }
 598
 599         if (new && stack) {
 600                 /* base the stack on post domain transition */
 601                 struct aa_label *base = new;
 602
 603                 new = aa_label_parse(base, stack, GFP_ATOMIC, true, false);
 604                 if (IS_ERR(new))
 605                         new = NULL;
 606                 aa_put_label(base);
 607         }
 608
 609         /* released by caller */
 610         return new;
 611 }
 612
 613 static struct aa_label *profile_transition(struct aa_profile *profile,
 614                                            const struct linux_binprm *bprm,
 615                                            char *buffer, struct path_cond *cond,
 616                                            bool *secure_exec)
 617 {
 618         struct aa_label *new = NULL;
 619         struct aa_profile *component;
 620         struct label_it i;
 621         const char *info = NULL, *name = NULL, *target = NULL;
 622         unsigned int state = profile->file.start;
 623         struct aa_perms perms = {};
 624         bool nonewprivs = false;
 625         int error = 0;
 626
 627         AA_BUG(!profile);
 628         AA_BUG(!bprm);
 629         AA_BUG(!buffer);
 630
 631         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 632                              &name, &info, profile->disconnected);
 633         if (error) {
 634                 if (profile_unconfined(profile) ||
 635                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 636                         AA_DEBUG("name lookup ix on error");
 637                         error = 0;
 638                         new = aa_get_newest_label(&profile->label);
 639                 }
 640                 name = bprm->filename;
 641                 goto audit;
 642         }
 643
 644         if (profile_unconfined(profile)) {
 645                 new = find_attach(bprm, profile->ns,
 646                                   &profile->ns->base.profiles, name, &info);
 647                 if (new) {
 648                         AA_DEBUG("unconfined attached to new label");
 649                         return new;
 650                 }
 651                 AA_DEBUG("unconfined exec no attachment");
 652                 return aa_get_newest_label(&profile->label);
 653         }
 654
 655         /* find exec permissions for name */
 656         state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
 657         if (perms.allow & MAY_EXEC) {
 658                 /* exec permission determine how to transition */
 659                 new = x_to_label(profile, bprm, name, perms.xindex, &target,
 660                                  &info);
 661                 if (new && new->proxy == profile->label.proxy && info) {
 662                         /* hack ix fallback - improve how this is detected */
 663                         goto audit;
 664                 } else if (!new) {
 665                         error = -EACCES;
 666                         info = "profile transition not found";
 667                         /* remove MAY_EXEC to audit as failure */
 668                         perms.allow &= ~MAY_EXEC;
 669                 } else {
 670                         /* verify that each component's xattr requirements are
 671                          * met, and fail execution otherwise
 672                          */
 673                         label_for_each(i, new, component) {
 674                                 if (aa_xattrs_match(bprm, component, state) <
 675                                     0) {
 676                                         error = -EACCES;
 677                                         info = "required xattrs not present";
 678                                         perms.allow &= ~MAY_EXEC;
 679                                         aa_put_label(new);
 680                                         new = NULL;
 681                                         goto audit;
 682                                 }
 683                         }
 684                 }
 685         } else if (COMPLAIN_MODE(profile)) {
 686                 /* no exec permission - learning mode */
 687                 struct aa_profile *new_profile = NULL;
 688                 char *n = kstrdup(name, GFP_ATOMIC);
 689
 690                 if (n) {
 691                         /* name is ptr into buffer */
 692                         long pos = name - buffer;
 693                         /* break per cpu buffer hold */
 694                         put_buffers(buffer);
 695                         new_profile = aa_new_null_profile(profile, false, n,
 696                                                           GFP_KERNEL);
 697                         get_buffers(buffer);
 698                         name = buffer + pos;
 699                         strcpy((char *)name, n);
 700                         kfree(n);
 701                 }
 702                 if (!new_profile) {
 703                         error = -ENOMEM;
 704                         info = "could not create null profile";
 705                 } else {
 706                         error = -EACCES;
 707                         new = &new_profile->label;
 708                 }
 709                 perms.xindex |= AA_X_UNSAFE;
 710         } else
 711                 /* fail exec */
 712                 error = -EACCES;
 713
 714         if (!new)
 715                 goto audit;
 716
 717
 718         if (!(perms.xindex & AA_X_UNSAFE)) {
 719                 if (DEBUG_ON) {
 720                         dbg_printk("apparmor: scrubbing environment variables"
 721                                    " for %s profile=", name);
 722                         aa_label_printk(new, GFP_ATOMIC);
 723                         dbg_printk("\n");
 724                 }
 725                 *secure_exec = true;
 726         }
 727
 728 audit:
 729         aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
 730                       cond->uid, info, error);
 731         if (!new || nonewprivs) {
 732                 aa_put_label(new);
 733                 return ERR_PTR(error);
 734         }
 735
 736         return new;
 737 }
 738
 739 static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
 740                           bool stack, const struct linux_binprm *bprm,
 741                           char *buffer, struct path_cond *cond,
 742                           bool *secure_exec)
 743 {
 744         unsigned int state = profile->file.start;
 745         struct aa_perms perms = {};
 746         const char *xname = NULL, *info = "change_profile onexec";
 747         int error = -EACCES;
 748
 749         AA_BUG(!profile);
 750         AA_BUG(!onexec);
 751         AA_BUG(!bprm);
 752         AA_BUG(!buffer);
 753
 754         if (profile_unconfined(profile)) {
 755                 /* change_profile on exec already granted */
 756                 /*
 757                  * NOTE: Domain transitions from unconfined are allowed
 758                  * even when no_new_privs is set because this aways results
 759                  * in a further reduction of permissions.
 760                  */
 761                 return 0;
 762         }
 763
 764         error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 765                              &xname, &info, profile->disconnected);
 766         if (error) {
 767                 if (profile_unconfined(profile) ||
 768                     (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 769                         AA_DEBUG("name lookup ix on error");
 770                         error = 0;
 771                 }
 772                 xname = bprm->filename;
 773                 goto audit;
 774         }
 775
 776         /* find exec permissions for name */
 777         state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
 778         if (!(perms.allow & AA_MAY_ONEXEC)) {
 779                 info = "no change_onexec valid for executable";
 780                 goto audit;
 781         }
 782         /* test if this exec can be paired with change_profile onexec.
 783          * onexec permission is linked to exec with a standard pairing
 784          * exec\0change_profile
 785          */
 786         state = aa_dfa_null_transition(profile->file.dfa, state);
 787         error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
 788                                      state, &perms);
 789         if (error) {
 790                 perms.allow &= ~AA_MAY_ONEXEC;
 791                 goto audit;
 792         }
 793
 794         if (!(perms.xindex & AA_X_UNSAFE)) {
 795                 if (DEBUG_ON) {
 796                         dbg_printk("apparmor: scrubbing environment "
 797                                    "variables for %s label=", xname);
 798                         aa_label_printk(onexec, GFP_ATOMIC);
 799                         dbg_printk("\n");
 800                 }
 801                 *secure_exec = true;
 802         }
 803
 804 audit:
 805         return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
 806                              NULL, onexec, cond->uid, info, error);
 807 }
 808
 809 /* ensure none ns domain transitions are correctly applied with onexec */
 810
 811 static struct aa_label *handle_onexec(struct aa_label *label,
 812                                       struct aa_label *onexec, bool stack,
 813                                       const struct linux_binprm *bprm,
 814                                       char *buffer, struct path_cond *cond,
 815                                       bool *unsafe)
 816 {
 817         struct aa_profile *profile;
 818         struct aa_label *new;
 819         int error;
 820
 821         AA_BUG(!label);
 822         AA_BUG(!onexec);
 823         AA_BUG(!bprm);
 824         AA_BUG(!buffer);
 825
 826         if (!stack) {
 827                 error = fn_for_each_in_ns(label, profile,
 828                                 profile_onexec(profile, onexec, stack,
 829                                                bprm, buffer, cond, unsafe));
 830                 if (error)
 831                         return ERR_PTR(error);
 832                 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
 833                                 aa_get_newest_label(onexec),
 834                                 profile_transition(profile, bprm, 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(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_ATOMIC,
 845                                 aa_label_merge(&profile->label, onexec,
 846                                                GFP_ATOMIC),
 847                                 profile_transition(profile, bprm, buffer,
 848                                                    cond, unsafe));
 849         }
 850
 851         if (new)
 852                 return new;
 853
 854         /* TODO: get rid of GLOBAL_ROOT_UID */
 855         error = fn_for_each_in_ns(label, profile,
 856                         aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
 857                                       AA_MAY_ONEXEC, bprm->filename, NULL,
 858                                       onexec, GLOBAL_ROOT_UID,
 859                                       "failed to build target label", -ENOMEM));
 860         return ERR_PTR(error);
 861 }
 862
 863 /**
 864  * apparmor_bprm_set_creds - set the new creds on the bprm struct
 865  * @bprm: binprm for the exec  (NOT NULL)
 866  *
 867  * Returns: %0 or error on failure
 868  *
 869  * TODO: once the other paths are done see if we can't refactor into a fn
 870  */
 871 int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 872 {
 873         struct aa_task_ctx *ctx;
 874         struct aa_label *label, *new = NULL;
 875         struct aa_profile *profile;
 876         char *buffer = NULL;
 877         const char *info = NULL;
 878         int error = 0;
 879         bool unsafe = false;
 880         struct path_cond cond = {
 881                 file_inode(bprm->file)->i_uid,
 882                 file_inode(bprm->file)->i_mode
 883         };
 884
 885         if (bprm->called_set_creds)
 886                 return 0;
 887
 888         ctx = task_ctx(current);
 889         AA_BUG(!cred_label(bprm->cred));
 890         AA_BUG(!ctx);
 891
 892         label = aa_get_newest_label(cred_label(bprm->cred));
 893
 894         /*
 895          * Detect no new privs being set, and store the label it
 896          * occurred under. Ideally this would happen when nnp
 897          * is set but there isn't a good way to do that yet.
 898          *
 899          * Testing for unconfined must be done before the subset test
 900          */
 901         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
 902             !ctx->nnp)
 903                 ctx->nnp = aa_get_label(label);
 904
 905         /* buffer freed below, name is pointer into buffer */
 906         get_buffers(buffer);
 907         /* Test for onexec first as onexec override other x transitions. */
 908         if (ctx->onexec)
 909                 new = handle_onexec(label, ctx->onexec, ctx->token,
 910                                     bprm, buffer, &cond, &unsafe);
 911         else
 912                 new = fn_label_build(label, profile, GFP_ATOMIC,
 913                                 profile_transition(profile, bprm, buffer,
 914                                                    &cond, &unsafe));
 915
 916         AA_BUG(!new);
 917         if (IS_ERR(new)) {
 918                 error = PTR_ERR(new);
 919                 goto done;
 920         } else if (!new) {
 921                 error = -ENOMEM;
 922                 goto done;
 923         }
 924
 925         /* Policy has specified a domain transitions. If no_new_privs and
 926          * confined ensure the transition is to confinement that is subset
 927          * of the confinement when the task entered no new privs.
 928          *
 929          * NOTE: Domain transitions from unconfined and to stacked
 930          * subsets are allowed even when no_new_privs is set because this
 931          * aways results in a further reduction of permissions.
 932          */
 933         if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
 934             !unconfined(label) && !aa_label_is_subset(new, ctx->nnp)) {
 935                 error = -EPERM;
 936                 info = "no new privs";
 937                 goto audit;
 938         }
 939
 940         if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 941                 /* FIXME: currently don't mediate shared state */
 942                 ;
 943         }
 944
 945         if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
 946                 /* TODO: test needs to be profile of label to new */
 947                 error = may_change_ptraced_domain(new, &info);
 948                 if (error)
 949                         goto audit;
 950         }
 951
 952         if (unsafe) {
 953                 if (DEBUG_ON) {
 954                         dbg_printk("scrubbing environment variables for %s "
 955                                    "label=", bprm->filename);
 956                         aa_label_printk(new, GFP_ATOMIC);
 957                         dbg_printk("\n");
 958                 }
 959                 bprm->secureexec = 1;
 960         }
 961
 962         if (label->proxy != new->proxy) {
 963                 /* when transitioning clear unsafe personality bits */
 964                 if (DEBUG_ON) {
 965                         dbg_printk("apparmor: clearing unsafe personality "
 966                                    "bits. %s label=", bprm->filename);
 967                         aa_label_printk(new, GFP_ATOMIC);
 968                         dbg_printk("\n");
 969                 }
 970                 bprm->per_clear |= PER_CLEAR_ON_SETID;
 971         }
 972         aa_put_label(cred_label(bprm->cred));
 973         /* transfer reference, released when cred is freed */
 974         set_cred_label(bprm->cred, new);
 975
 976 done:
 977         aa_put_label(label);
 978         put_buffers(buffer);
 979
 980         return error;
 981
 982 audit:
 983         error = fn_for_each(label, profile,
 984                         aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
 985                                       bprm->filename, NULL, new,
 986                                       file_inode(bprm->file)->i_uid, info,
 987                                       error));
 988         aa_put_label(new);
 989         goto done;
 990 }
 991
 992 /*
 993  * Functions for self directed profile change
 994  */
 995
 996
 997 /* helper fn for change_hat
 998  *
 999  * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
1000  */
1001 static struct aa_label *build_change_hat(struct aa_profile *profile,
1002                                          const char *name, bool sibling)
1003 {
1004         struct aa_profile *root, *hat = NULL;
1005         const char *info = NULL;
1006         int error = 0;
1007
1008         if (sibling && PROFILE_IS_HAT(profile)) {
1009                 root = aa_get_profile_rcu(&profile->parent);
1010         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1011                 root = aa_get_profile(profile);
1012         } else {
1013                 info = "conflicting target types";
1014                 error = -EPERM;
1015                 goto audit;
1016         }
1017
1018         hat = aa_find_child(root, name);
1019         if (!hat) {
1020                 error = -ENOENT;
1021                 if (COMPLAIN_MODE(profile)) {
1022                         hat = aa_new_null_profile(profile, true, name,
1023                                                   GFP_KERNEL);
1024                         if (!hat) {
1025                                 info = "failed null profile create";
1026                                 error = -ENOMEM;
1027                         }
1028                 }
1029         }
1030         aa_put_profile(root);
1031
1032 audit:
1033         aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1034                       name, hat ? hat->base.hname : NULL,
1035                       hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1036                       error);
1037         if (!hat || (error && error != -ENOENT))
1038                 return ERR_PTR(error);
1039         /* if hat && error - complain mode, already audited and we adjust for
1040          * complain mode allow by returning hat->label
1041          */
1042         return &hat->label;
1043 }
1044
1045 /* helper fn for changing into a hat
1046  *
1047  * Returns: label for hat transition or ERR_PTR. Does not return NULL
1048  */
1049 static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1050                                    int count, int flags)
1051 {
1052         struct aa_profile *profile, *root, *hat = NULL;
1053         struct aa_label *new;
1054         struct label_it it;
1055         bool sibling = false;
1056         const char *name, *info = NULL;
1057         int i, error;
1058
1059         AA_BUG(!label);
1060         AA_BUG(!hats);
1061         AA_BUG(count < 1);
1062
1063         if (PROFILE_IS_HAT(labels_profile(label)))
1064                 sibling = true;
1065
1066         /*find first matching hat */
1067         for (i = 0; i < count && !hat; i++) {
1068                 name = hats[i];
1069                 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1070                         if (sibling && PROFILE_IS_HAT(profile)) {
1071                                 root = aa_get_profile_rcu(&profile->parent);
1072                         } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1073                                 root = aa_get_profile(profile);
1074                         } else {        /* conflicting change type */
1075                                 info = "conflicting targets types";
1076                                 error = -EPERM;
1077                                 goto fail;
1078                         }
1079                         hat = aa_find_child(root, name);
1080                         aa_put_profile(root);
1081                         if (!hat) {
1082                                 if (!COMPLAIN_MODE(profile))
1083                                         goto outer_continue;
1084                                 /* complain mode succeed as if hat */
1085                         } else if (!PROFILE_IS_HAT(hat)) {
1086                                 info = "target not hat";
1087                                 error = -EPERM;
1088                                 aa_put_profile(hat);
1089                                 goto fail;
1090                         }
1091                         aa_put_profile(hat);
1092                 }
1093                 /* found a hat for all profiles in ns */
1094                 goto build;
1095 outer_continue:
1096         ;
1097         }
1098         /* no hats that match, find appropriate error
1099          *
1100          * In complain mode audit of the failure is based off of the first
1101          * hat supplied.  This is done due how userspace interacts with
1102          * change_hat.
1103          */
1104         name = NULL;
1105         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1106                 if (!list_empty(&profile->base.profiles)) {
1107                         info = "hat not found";
1108                         error = -ENOENT;
1109                         goto fail;
1110                 }
1111         }
1112         info = "no hats defined";
1113         error = -ECHILD;
1114
1115 fail:
1116         label_for_each_in_ns(it, labels_ns(label), label, profile) {
1117                 /*
1118                  * no target as it has failed to be found or built
1119                  *
1120                  * change_hat uses probing and should not log failures
1121                  * related to missing hats
1122                  */
1123                 /* TODO: get rid of GLOBAL_ROOT_UID */
1124                 if (count > 1 || COMPLAIN_MODE(profile)) {
1125                         aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1126                                       AA_MAY_CHANGEHAT, name, NULL, NULL,
1127                                       GLOBAL_ROOT_UID, info, error);
1128                 }
1129         }
1130         return ERR_PTR(error);
1131
1132 build:
1133         new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1134                                    build_change_hat(profile, name, sibling),
1135                                    aa_get_label(&profile->label));
1136         if (!new) {
1137                 info = "label build failed";
1138                 error = -ENOMEM;
1139                 goto fail;
1140         } /* else if (IS_ERR) build_change_hat has logged error so return new */
1141
1142         return new;
1143 }
1144
1145 /**
1146  * aa_change_hat - change hat to/from subprofile
1147  * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1148  * @count: number of hat names in @hats
1149  * @token: magic value to validate the hat change
1150  * @flags: flags affecting behavior of the change
1151  *
1152  * Returns %0 on success, error otherwise.
1153  *
1154  * Change to the first profile specified in @hats that exists, and store
1155  * the @hat_magic in the current task context.  If the count == 0 and the
1156  * @token matches that stored in the current task context, return to the
1157  * top level profile.
1158  *
1159  * change_hat only applies to profiles in the current ns, and each profile
1160  * in the ns must make the same transition otherwise change_hat will fail.
1161  */
1162 int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1163 {
1164         const struct cred *cred;
1165         struct aa_task_ctx *ctx = task_ctx(current);
1166         struct aa_label *label, *previous, *new = NULL, *target = NULL;
1167         struct aa_profile *profile;
1168         struct aa_perms perms = {};
1169         const char *info = NULL;
1170         int error = 0;
1171
1172         /* released below */
1173         cred = get_current_cred();
1174         label = aa_get_newest_cred_label(cred);
1175         previous = aa_get_newest_label(ctx->previous);
1176
1177         /*
1178          * Detect no new privs being set, and store the label it
1179          * occurred under. Ideally this would happen when nnp
1180          * is set but there isn't a good way to do that yet.
1181          *
1182          * Testing for unconfined must be done before the subset test
1183          */
1184         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1185                 ctx->nnp = aa_get_label(label);
1186
1187         if (unconfined(label)) {
1188                 info = "unconfined can not change_hat";
1189                 error = -EPERM;
1190                 goto fail;
1191         }
1192
1193         if (count) {
1194                 new = change_hat(label, hats, count, flags);
1195                 AA_BUG(!new);
1196                 if (IS_ERR(new)) {
1197                         error = PTR_ERR(new);
1198                         new = NULL;
1199                         /* already audited */
1200                         goto out;
1201                 }
1202
1203                 error = may_change_ptraced_domain(new, &info);
1204                 if (error)
1205                         goto fail;
1206
1207                 /*
1208                  * no new privs prevents domain transitions that would
1209                  * reduce restrictions.
1210                  */
1211                 if (task_no_new_privs(current) && !unconfined(label) &&
1212                     !aa_label_is_subset(new, ctx->nnp)) {
1213                         /* not an apparmor denial per se, so don't log it */
1214                         AA_DEBUG("no_new_privs - change_hat denied");
1215                         error = -EPERM;
1216                         goto out;
1217                 }
1218
1219                 if (flags & AA_CHANGE_TEST)
1220                         goto out;
1221
1222                 target = new;
1223                 error = aa_set_current_hat(new, token);
1224                 if (error == -EACCES)
1225                         /* kill task in case of brute force attacks */
1226                         goto kill;
1227         } else if (previous && !(flags & AA_CHANGE_TEST)) {
1228                 /*
1229                  * no new privs prevents domain transitions that would
1230                  * reduce restrictions.
1231                  */
1232                 if (task_no_new_privs(current) && !unconfined(label) &&
1233                     !aa_label_is_subset(previous, ctx->nnp)) {
1234                         /* not an apparmor denial per se, so don't log it */
1235                         AA_DEBUG("no_new_privs - change_hat denied");
1236                         error = -EPERM;
1237                         goto out;
1238                 }
1239
1240                 /* Return to saved label.  Kill task if restore fails
1241                  * to avoid brute force attacks
1242                  */
1243                 target = previous;
1244                 error = aa_restore_previous_label(token);
1245                 if (error) {
1246                         if (error == -EACCES)
1247                                 goto kill;
1248                         goto fail;
1249                 }
1250         } /* else ignore @flags && restores when there is no saved profile */
1251
1252 out:
1253         aa_put_label(new);
1254         aa_put_label(previous);
1255         aa_put_label(label);
1256         put_cred(cred);
1257
1258         return error;
1259
1260 kill:
1261         info = "failed token match";
1262         perms.kill = AA_MAY_CHANGEHAT;
1263
1264 fail:
1265         fn_for_each_in_ns(label, profile,
1266                 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1267                               AA_MAY_CHANGEHAT, NULL, NULL, target,
1268                               GLOBAL_ROOT_UID, info, error));
1269
1270         goto out;
1271 }
1272
1273
1274 static int change_profile_perms_wrapper(const char *op, const char *name,
1275                                         struct aa_profile *profile,
1276                                         struct aa_label *target, bool stack,
1277                                         u32 request, struct aa_perms *perms)
1278 {
1279         const char *info = NULL;
1280         int error = 0;
1281
1282         if (!error)
1283                 error = change_profile_perms(profile, target, stack, request,
1284                                              profile->file.start, perms);
1285         if (error)
1286                 error = aa_audit_file(profile, perms, op, request, name,
1287                                       NULL, target, GLOBAL_ROOT_UID, info,
1288                                       error);
1289
1290         return error;
1291 }
1292
1293 /**
1294  * aa_change_profile - perform a one-way profile transition
1295  * @fqname: name of profile may include namespace (NOT NULL)
1296  * @onexec: whether this transition is to take place immediately or at exec
1297  * @flags: flags affecting change behavior
1298  *
1299  * Change to new profile @name.  Unlike with hats, there is no way
1300  * to change back.  If @name isn't specified the current profile name is
1301  * used.
1302  * If @onexec then the transition is delayed until
1303  * the next exec.
1304  *
1305  * Returns %0 on success, error otherwise.
1306  */
1307 int aa_change_profile(const char *fqname, int flags)
1308 {
1309         struct aa_label *label, *new = NULL, *target = NULL;
1310         struct aa_profile *profile;
1311         struct aa_perms perms = {};
1312         const char *info = NULL;
1313         const char *auditname = fqname;         /* retain leading & if stack */
1314         bool stack = flags & AA_CHANGE_STACK;
1315         struct aa_task_ctx *ctx = task_ctx(current);
1316         int error = 0;
1317         char *op;
1318         u32 request;
1319
1320         label = aa_get_current_label();
1321
1322         /*
1323          * Detect no new privs being set, and store the label it
1324          * occurred under. Ideally this would happen when nnp
1325          * is set but there isn't a good way to do that yet.
1326          *
1327          * Testing for unconfined must be done before the subset test
1328          */
1329         if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1330                 ctx->nnp = aa_get_label(label);
1331
1332         if (!fqname || !*fqname) {
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         label = aa_get_current_label();
1352
1353         if (*fqname == '&') {
1354                 stack = true;
1355                 /* don't have label_parse() do stacking */
1356                 fqname++;
1357         }
1358         target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1359         if (IS_ERR(target)) {
1360                 struct aa_profile *tprofile;
1361
1362                 info = "label not found";
1363                 error = PTR_ERR(target);
1364                 target = NULL;
1365                 /*
1366                  * TODO: fixme using labels_profile is not right - do profile
1367                  * per complain profile
1368                  */
1369                 if ((flags & AA_CHANGE_TEST) ||
1370                     !COMPLAIN_MODE(labels_profile(label)))
1371                         goto audit;
1372                 /* released below */
1373                 tprofile = aa_new_null_profile(labels_profile(label), false,
1374                                                fqname, GFP_KERNEL);
1375                 if (!tprofile) {
1376                         info = "failed null profile create";
1377                         error = -ENOMEM;
1378                         goto audit;
1379                 }
1380                 target = &tprofile->label;
1381                 goto check;
1382         }
1383
1384         /*
1385          * self directed transitions only apply to current policy ns
1386          * TODO: currently requiring perms for stacking and straight change
1387          *       stacking doesn't strictly need this. Determine how much
1388          *       we want to loosen this restriction for stacking
1389          *
1390          * if (!stack) {
1391          */
1392         error = fn_for_each_in_ns(label, profile,
1393                         change_profile_perms_wrapper(op, auditname,
1394                                                      profile, target, stack,
1395                                                      request, &perms));
1396         if (error)
1397                 /* auditing done in change_profile_perms_wrapper */
1398                 goto out;
1399
1400         /* } */
1401
1402 check:
1403         /* check if tracing task is allowed to trace target domain */
1404         error = may_change_ptraced_domain(target, &info);
1405         if (error && !fn_for_each_in_ns(label, profile,
1406                                         COMPLAIN_MODE(profile)))
1407                 goto audit;
1408
1409         /* TODO: add permission check to allow this
1410          * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1411          *      info = "not a single threaded task";
1412          *      error = -EACCES;
1413          *      goto audit;
1414          * }
1415          */
1416         if (flags & AA_CHANGE_TEST)
1417                 goto out;
1418
1419         /* stacking is always a subset, so only check the nonstack case */
1420         if (!stack) {
1421                 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1422                                            aa_get_label(target),
1423                                            aa_get_label(&profile->label));
1424                 /*
1425                  * no new privs prevents domain transitions that would
1426                  * reduce restrictions.
1427                  */
1428                 if (task_no_new_privs(current) && !unconfined(label) &&
1429                     !aa_label_is_subset(new, ctx->nnp)) {
1430                         /* not an apparmor denial per se, so don't log it */
1431                         AA_DEBUG("no_new_privs - change_hat denied");
1432                         error = -EPERM;
1433                         goto out;
1434                 }
1435         }
1436
1437         if (!(flags & AA_CHANGE_ONEXEC)) {
1438                 /* only transition profiles in the current ns */
1439                 if (stack)
1440                         new = aa_label_merge(label, target, GFP_KERNEL);
1441                 if (IS_ERR_OR_NULL(new)) {
1442                         info = "failed to build target label";
1443                         if (!new)
1444                                 error = -ENOMEM;
1445                         else
1446                                 error = PTR_ERR(new);
1447                         new = NULL;
1448                         perms.allow = 0;
1449                         goto audit;
1450                 }
1451                 error = aa_replace_current_label(new);
1452         } else {
1453                 if (new) {
1454                         aa_put_label(new);
1455                         new = NULL;
1456                 }
1457
1458                 /* full transition will be built in exec path */
1459                 error = aa_set_current_onexec(target, stack);
1460         }
1461
1462 audit:
1463         error = fn_for_each_in_ns(label, profile,
1464                         aa_audit_file(profile, &perms, op, request, auditname,
1465                                       NULL, new ? new : target,
1466                                       GLOBAL_ROOT_UID, info, error));
1467
1468 out:
1469         aa_put_label(new);
1470         aa_put_label(target);
1471         aa_put_label(label);
1472
1473         return error;
1474 }