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