security/apparmor/domain.c

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor policy attachment and domain transitions
   5  *
   6  * Copyright (C) 2002-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #include <linux/errno.h>
  16 #include <linux/fdtable.h>
  17 #include <linux/file.h>
  18 #include <linux/mount.h>
  19 #include <linux/syscalls.h>
  20 #include <linux/tracehook.h>
  21 #include <linux/personality.h>
  22
  23 #include "include/audit.h"
  24 #include "include/apparmorfs.h"
  25 #include "include/context.h"
  26 #include "include/domain.h"
  27 #include "include/file.h"
  28 #include "include/ipc.h"
  29 #include "include/match.h"
  30 #include "include/path.h"
  31 #include "include/policy.h"
  32
  33 /**
  34  * aa_free_domain_entries - free entries in a domain table
  35  * @domain: the domain table to free  (MAYBE NULL)
  36  */
  37 void aa_free_domain_entries(struct aa_domain *domain)
  38 {
  39         int i;
  40         if (domain) {
  41                 if (!domain->table)
  42                         return;
  43
  44                 for (i = 0; i < domain->size; i++)
  45                         kzfree(domain->table[i]);
  46                 kzfree(domain->table);
  47                 domain->table = NULL;
  48         }
  49 }
  50
  51 /**
  52  * may_change_ptraced_domain - check if can change profile on ptraced task
  53  * @task: task we want to change profile of   (NOT NULL)
  54  * @to_profile: profile to change to  (NOT NULL)
  55  *
  56  * Check if the task is ptraced and if so if the tracing task is allowed
  57  * to trace the new domain
  58  *
  59  * Returns: %0 or error if change not allowed
  60  */
  61 static int may_change_ptraced_domain(struct task_struct *task,
  62                                      struct aa_profile *to_profile)
  63 {
  64         struct task_struct *tracer;
  65         const struct cred *cred = NULL;
  66         struct aa_profile *tracerp = NULL;
  67         int error = 0;
  68
  69         rcu_read_lock();
  70         tracer = ptrace_parent(task);
  71         if (tracer) {
  72                 /* released below */
  73                 cred = get_task_cred(tracer);
  74                 tracerp = aa_cred_profile(cred);
  75         }
  76
  77         /* not ptraced */
  78         if (!tracer || unconfined(tracerp))
  79                 goto out;
  80
  81         error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH);
  82
  83 out:
  84         rcu_read_unlock();
  85         if (cred)
  86                 put_cred(cred);
  87
  88         return error;
  89 }
  90
  91 /**
  92  * change_profile_perms - find permissions for change_profile
  93  * @profile: the current profile  (NOT NULL)
  94  * @ns: the namespace being switched to  (NOT NULL)
  95  * @name: the name of the profile to change to  (NOT NULL)
  96  * @request: requested perms
  97  * @start: state to start matching in
  98  *
  99  * Returns: permission set
 100  */
 101 static struct file_perms change_profile_perms(struct aa_profile *profile,
 102                                               struct aa_namespace *ns,
 103                                               const char *name, u32 request,
 104                                               unsigned int start)
 105 {
 106         struct file_perms perms;
 107         struct path_cond cond = { };
 108         unsigned int state;
 109
 110         if (unconfined(profile)) {
 111                 perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
 112                 perms.audit = perms.quiet = perms.kill = 0;
 113                 return perms;
 114         } else if (!profile->file.dfa) {
 115                 return nullperms;
 116         } else if ((ns == profile->ns)) {
 117                 /* try matching against rules with out namespace prepended */
 118                 aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
 119                 if (COMBINED_PERM_MASK(perms) & request)
 120                         return perms;
 121         }
 122
 123         /* try matching with namespace name and then profile */
 124         state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
 125         state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
 126         aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
 127
 128         return perms;
 129 }
 130
 131 /**
 132  * __attach_match_ - find an attachment match
 133  * @name - to match against  (NOT NULL)
 134  * @head - profile list to walk  (NOT NULL)
 135  *
 136  * Do a linear search on the profiles in the list.  There is a matching
 137  * preference where an exact match is preferred over a name which uses
 138  * expressions to match, and matching expressions with the greatest
 139  * xmatch_len are preferred.
 140  *
 141  * Requires: @head not be shared or have appropriate locks held
 142  *
 143  * Returns: profile or NULL if no match found
 144  */
 145 static struct aa_profile *__attach_match(const char *name,
 146                                          struct list_head *head)
 147 {
 148         int len = 0;
 149         struct aa_profile *profile, *candidate = NULL;
 150
 151         list_for_each_entry(profile, head, base.list) {
 152                 if (profile->flags & PFLAG_NULL)
 153                         continue;
 154                 if (profile->xmatch && profile->xmatch_len > len) {
 155                         unsigned int state = aa_dfa_match(profile->xmatch,
 156                                                           DFA_START, name);
 157                         u32 perm = dfa_user_allow(profile->xmatch, state);
 158                         /* any accepting state means a valid match. */
 159                         if (perm & MAY_EXEC) {
 160                                 candidate = profile;
 161                                 len = profile->xmatch_len;
 162                         }
 163                 } else if (!strcmp(profile->base.name, name))
 164                         /* exact non-re match, no more searching required */
 165                         return profile;
 166         }
 167
 168         return candidate;
 169 }
 170
 171 /**
 172  * find_attach - do attachment search for unconfined processes
 173  * @ns: the current namespace  (NOT NULL)
 174  * @list: list to search  (NOT NULL)
 175  * @name: the executable name to match against  (NOT NULL)
 176  *
 177  * Returns: profile or NULL if no match found
 178  */
 179 static struct aa_profile *find_attach(struct aa_namespace *ns,
 180                                       struct list_head *list, const char *name)
 181 {
 182         struct aa_profile *profile;
 183
 184         read_lock(&ns->lock);
 185         profile = aa_get_profile(__attach_match(name, list));
 186         read_unlock(&ns->lock);
 187
 188         return profile;
 189 }
 190
 191 /**
 192  * separate_fqname - separate the namespace and profile names
 193  * @fqname: the fqname name to split  (NOT NULL)
 194  * @ns_name: the namespace name if it exists  (NOT NULL)
 195  *
 196  * This is the xtable equivalent routine of aa_split_fqname.  It finds the
 197  * split in an xtable fqname which contains an embedded \0 instead of a :
 198  * if a namespace is specified.  This is done so the xtable is constant and
 199  * isn't re-split on every lookup.
 200  *
 201  * Either the profile or namespace name may be optional but if the namespace
 202  * is specified the profile name termination must be present.  This results
 203  * in the following possible encodings:
 204  * profile_name\0
 205  * :ns_name\0profile_name\0
 206  * :ns_name\0\0
 207  *
 208  * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
 209  *
 210  * Returns: profile name if it is specified else NULL
 211  */
 212 static const char *separate_fqname(const char *fqname, const char **ns_name)
 213 {
 214         const char *name;
 215
 216         if (fqname[0] == ':') {
 217                 /* In this case there is guaranteed to be two \0 terminators
 218                  * in the string.  They are verified at load time by
 219                  * by unpack_trans_table
 220                  */
 221                 *ns_name = fqname + 1;          /* skip : */
 222                 name = *ns_name + strlen(*ns_name) + 1;
 223                 if (!*name)
 224                         name = NULL;
 225         } else {
 226                 *ns_name = NULL;
 227                 name = fqname;
 228         }
 229
 230         return name;
 231 }
 232
 233 static const char *next_name(int xtype, const char *name)
 234 {
 235         return NULL;
 236 }
 237
 238 /**
 239  * x_table_lookup - lookup an x transition name via transition table
 240  * @profile: current profile (NOT NULL)
 241  * @xindex: index into x transition table
 242  *
 243  * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
 244  */
 245 static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
 246 {
 247         struct aa_profile *new_profile = NULL;
 248         struct aa_namespace *ns = profile->ns;
 249         u32 xtype = xindex & AA_X_TYPE_MASK;
 250         int index = xindex & AA_X_INDEX_MASK;
 251         const char *name;
 252
 253         /* index is guaranteed to be in range, validated at load time */
 254         for (name = profile->file.trans.table[index]; !new_profile && name;
 255              name = next_name(xtype, name)) {
 256                 struct aa_namespace *new_ns;
 257                 const char *xname = NULL;
 258
 259                 new_ns = NULL;
 260                 if (xindex & AA_X_CHILD) {
 261                         /* release by caller */
 262                         new_profile = aa_find_child(profile, name);
 263                         continue;
 264                 } else if (*name == ':') {
 265                         /* switching namespace */
 266                         const char *ns_name;
 267                         xname = name = separate_fqname(name, &ns_name);
 268                         if (!xname)
 269                                 /* no name so use profile name */
 270                                 xname = profile->base.hname;
 271                         if (*ns_name == '@') {
 272                                 /* TODO: variable support */
 273                                 ;
 274                         }
 275                         /* released below */
 276                         new_ns = aa_find_namespace(ns, ns_name);
 277                         if (!new_ns)
 278                                 continue;
 279                 } else if (*name == '@') {
 280                         /* TODO: variable support */
 281                         continue;
 282                 } else {
 283                         /* basic namespace lookup */
 284                         xname = name;
 285                 }
 286
 287                 /* released by caller */
 288                 new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
 289                 aa_put_namespace(new_ns);
 290         }
 291
 292         /* released by caller */
 293         return new_profile;
 294 }
 295
 296 /**
 297  * x_to_profile - get target profile for a given xindex
 298  * @profile: current profile  (NOT NULL)
 299  * @name: name to lookup (NOT NULL)
 300  * @xindex: index into x transition table
 301  *
 302  * find profile for a transition index
 303  *
 304  * Returns: refcounted profile or NULL if not found available
 305  */
 306 static struct aa_profile *x_to_profile(struct aa_profile *profile,
 307                                        const char *name, u32 xindex)
 308 {
 309         struct aa_profile *new_profile = NULL;
 310         struct aa_namespace *ns = profile->ns;
 311         u32 xtype = xindex & AA_X_TYPE_MASK;
 312
 313         switch (xtype) {
 314         case AA_X_NONE:
 315                 /* fail exec unless ix || ux fallback - handled by caller */
 316                 return NULL;
 317         case AA_X_NAME:
 318                 if (xindex & AA_X_CHILD)
 319                         /* released by caller */
 320                         new_profile = find_attach(ns, &profile->base.profiles,
 321                                                   name);
 322                 else
 323                         /* released by caller */
 324                         new_profile = find_attach(ns, &ns->base.profiles,
 325                                                   name);
 326                 break;
 327         case AA_X_TABLE:
 328                 /* released by caller */
 329                 new_profile = x_table_lookup(profile, xindex);
 330                 break;
 331         }
 332
 333         /* released by caller */
 334         return new_profile;
 335 }
 336
 337 /**
 338  * apparmor_bprm_set_creds - set the new creds on the bprm struct
 339  * @bprm: binprm for the exec  (NOT NULL)
 340  *
 341  * Returns: %0 or error on failure
 342  */
 343 int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 344 {
 345         struct aa_task_cxt *cxt;
 346         struct aa_profile *profile, *new_profile = NULL;
 347         struct aa_namespace *ns;
 348         char *buffer = NULL;
 349         unsigned int state;
 350         struct file_perms perms = {};
 351         struct path_cond cond = {
 352                 bprm->file->f_path.dentry->d_inode->i_uid,
 353                 bprm->file->f_path.dentry->d_inode->i_mode
 354         };
 355         const char *name = NULL, *target = NULL, *info = NULL;
 356         int error = cap_bprm_set_creds(bprm);
 357         if (error)
 358                 return error;
 359
 360         if (bprm->cred_prepared)
 361                 return 0;
 362
 363         cxt = bprm->cred->security;
 364         BUG_ON(!cxt);
 365
 366         profile = aa_get_profile(aa_newest_version(cxt->profile));
 367         /*
 368          * get the namespace from the replacement profile as replacement
 369          * can change the namespace
 370          */
 371         ns = profile->ns;
 372         state = profile->file.start;
 373
 374         /* buffer freed below, name is pointer into buffer */
 375         error = aa_get_name(&bprm->file->f_path, profile->path_flags, &buffer,
 376                             &name);
 377         if (error) {
 378                 if (profile->flags &
 379                     (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED))
 380                         error = 0;
 381                 info = "Exec failed name resolution";
 382                 name = bprm->filename;
 383                 goto audit;
 384         }
 385
 386         /* Test for onexec first as onexec directives override other
 387          * x transitions.
 388          */
 389         if (unconfined(profile)) {
 390                 /* unconfined task */
 391                 if (cxt->onexec)
 392                         /* change_profile on exec already been granted */
 393                         new_profile = aa_get_profile(cxt->onexec);
 394                 else
 395                         new_profile = find_attach(ns, &ns->base.profiles, name);
 396                 if (!new_profile)
 397                         goto cleanup;
 398                 goto apply;
 399         }
 400
 401         /* find exec permissions for name */
 402         state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
 403         if (cxt->onexec) {
 404                 struct file_perms cp;
 405                 info = "change_profile onexec";
 406                 if (!(perms.allow & AA_MAY_ONEXEC))
 407                         goto audit;
 408
 409                 /* test if this exec can be paired with change_profile onexec.
 410                  * onexec permission is linked to exec with a standard pairing
 411                  * exec\0change_profile
 412                  */
 413                 state = aa_dfa_null_transition(profile->file.dfa, state);
 414                 cp = change_profile_perms(profile, cxt->onexec->ns, name,
 415                                           AA_MAY_ONEXEC, state);
 416
 417                 if (!(cp.allow & AA_MAY_ONEXEC))
 418                         goto audit;
 419                 new_profile = aa_get_profile(aa_newest_version(cxt->onexec));
 420                 goto apply;
 421         }
 422
 423         if (perms.allow & MAY_EXEC) {
 424                 /* exec permission determine how to transition */
 425                 new_profile = x_to_profile(profile, name, perms.xindex);
 426                 if (!new_profile) {
 427                         if (perms.xindex & AA_X_INHERIT) {
 428                                 /* (p|c|n)ix - don't change profile but do
 429                                  * use the newest version, which was picked
 430                                  * up above when getting profile
 431                                  */
 432                                 info = "ix fallback";
 433                                 new_profile = aa_get_profile(profile);
 434                                 goto x_clear;
 435                         } else if (perms.xindex & AA_X_UNCONFINED) {
 436                                 new_profile = aa_get_profile(ns->unconfined);
 437                                 info = "ux fallback";
 438                         } else {
 439                                 error = -ENOENT;
 440                                 info = "profile not found";
 441                         }
 442                 }
 443         } else if (COMPLAIN_MODE(profile)) {
 444                 /* no exec permission - are we in learning mode */
 445                 new_profile = aa_new_null_profile(profile, 0);
 446                 if (!new_profile) {
 447                         error = -ENOMEM;
 448                         info = "could not create null profile";
 449                 } else {
 450                         error = -EACCES;
 451                         target = new_profile->base.hname;
 452                 }
 453                 perms.xindex |= AA_X_UNSAFE;
 454         } else
 455                 /* fail exec */
 456                 error = -EACCES;
 457
 458         if (!new_profile)
 459                 goto audit;
 460
 461         if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 462                 /* FIXME: currently don't mediate shared state */
 463                 ;
 464         }
 465
 466         if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
 467                 error = may_change_ptraced_domain(current, new_profile);
 468                 if (error) {
 469                         aa_put_profile(new_profile);
 470                         goto audit;
 471                 }
 472         }
 473
 474         /* Determine if secure exec is needed.
 475          * Can be at this point for the following reasons:
 476          * 1. unconfined switching to confined
 477          * 2. confined switching to different confinement
 478          * 3. confined switching to unconfined
 479          *
 480          * Cases 2 and 3 are marked as requiring secure exec
 481          * (unless policy specified "unsafe exec")
 482          *
 483          * bprm->unsafe is used to cache the AA_X_UNSAFE permission
 484          * to avoid having to recompute in secureexec
 485          */
 486         if (!(perms.xindex & AA_X_UNSAFE)) {
 487                 AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
 488                          name, new_profile->base.hname);
 489                 bprm->unsafe |= AA_SECURE_X_NEEDED;
 490         }
 491 apply:
 492         target = new_profile->base.hname;
 493         /* when transitioning profiles clear unsafe personality bits */
 494         bprm->per_clear |= PER_CLEAR_ON_SETID;
 495
 496 x_clear:
 497         aa_put_profile(cxt->profile);
 498         /* transfer new profile reference will be released when cxt is freed */
 499         cxt->profile = new_profile;
 500
 501         /* clear out all temporary/transitional state from the context */
 502         aa_put_profile(cxt->previous);
 503         aa_put_profile(cxt->onexec);
 504         cxt->previous = NULL;
 505         cxt->onexec = NULL;
 506         cxt->token = 0;
 507
 508 audit:
 509         error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
 510                               name, target, cond.uid, info, error);
 511
 512 cleanup:
 513         aa_put_profile(profile);
 514         kfree(buffer);
 515
 516         return error;
 517 }
 518
 519 /**
 520  * apparmor_bprm_secureexec - determine if secureexec is needed
 521  * @bprm: binprm for exec  (NOT NULL)
 522  *
 523  * Returns: %1 if secureexec is needed else %0
 524  */
 525 int apparmor_bprm_secureexec(struct linux_binprm *bprm)
 526 {
 527         int ret = cap_bprm_secureexec(bprm);
 528
 529         /* the decision to use secure exec is computed in set_creds
 530          * and stored in bprm->unsafe.
 531          */
 532         if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
 533                 ret = 1;
 534
 535         return ret;
 536 }
 537
 538 /**
 539  * apparmor_bprm_committing_creds - do task cleanup on committing new creds
 540  * @bprm: binprm for the exec  (NOT NULL)
 541  */
 542 void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
 543 {
 544         struct aa_profile *profile = __aa_current_profile();
 545         struct aa_task_cxt *new_cxt = bprm->cred->security;
 546
 547         /* bail out if unconfined or not changing profile */
 548         if ((new_cxt->profile == profile) ||
 549             (unconfined(new_cxt->profile)))
 550                 return;
 551
 552         current->pdeath_signal = 0;
 553
 554         /* reset soft limits and set hard limits for the new profile */
 555         __aa_transition_rlimits(profile, new_cxt->profile);
 556 }
 557
 558 /**
 559  * apparmor_bprm_commited_cred - do cleanup after new creds committed
 560  * @bprm: binprm for the exec  (NOT NULL)
 561  */
 562 void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 563 {
 564         /* TODO: cleanup signals - ipc mediation */
 565         return;
 566 }
 567
 568 /*
 569  * Functions for self directed profile change
 570  */
 571
 572 /**
 573  * new_compound_name - create an hname with @n2 appended to @n1
 574  * @n1: base of hname  (NOT NULL)
 575  * @n2: name to append (NOT NULL)
 576  *
 577  * Returns: new name or NULL on error
 578  */
 579 static char *new_compound_name(const char *n1, const char *n2)
 580 {
 581         char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
 582         if (name)
 583                 sprintf(name, "%s//%s", n1, n2);
 584         return name;
 585 }
 586
 587 /**
 588  * aa_change_hat - change hat to/from subprofile
 589  * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
 590  * @count: number of hat names in @hats
 591  * @token: magic value to validate the hat change
 592  * @permtest: true if this is just a permission test
 593  *
 594  * Change to the first profile specified in @hats that exists, and store
 595  * the @hat_magic in the current task context.  If the count == 0 and the
 596  * @token matches that stored in the current task context, return to the
 597  * top level profile.
 598  *
 599  * Returns %0 on success, error otherwise.
 600  */
 601 int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
 602 {
 603         const struct cred *cred;
 604         struct aa_task_cxt *cxt;
 605         struct aa_profile *profile, *previous_profile, *hat = NULL;
 606         char *name = NULL;
 607         int i;
 608         struct file_perms perms = {};
 609         const char *target = NULL, *info = NULL;
 610         int error = 0;
 611
 612         /* released below */
 613         cred = get_current_cred();
 614         cxt = cred->security;
 615         profile = aa_cred_profile(cred);
 616         previous_profile = cxt->previous;
 617
 618         if (unconfined(profile)) {
 619                 info = "unconfined";
 620                 error = -EPERM;
 621                 goto audit;
 622         }
 623
 624         if (count) {
 625                 /* attempting to change into a new hat or switch to a sibling */
 626                 struct aa_profile *root;
 627                 root = PROFILE_IS_HAT(profile) ? profile->parent : profile;
 628
 629                 /* find first matching hat */
 630                 for (i = 0; i < count && !hat; i++)
 631                         /* released below */
 632                         hat = aa_find_child(root, hats[i]);
 633                 if (!hat) {
 634                         if (!COMPLAIN_MODE(root) || permtest) {
 635                                 if (list_empty(&root->base.profiles))
 636                                         error = -ECHILD;
 637                                 else
 638                                         error = -ENOENT;
 639                                 goto out;
 640                         }
 641
 642                         /*
 643                          * In complain mode and failed to match any hats.
 644                          * Audit the failure is based off of the first hat
 645                          * supplied.  This is done due how userspace
 646                          * interacts with change_hat.
 647                          *
 648                          * TODO: Add logging of all failed hats
 649                          */
 650
 651                         /* freed below */
 652                         name = new_compound_name(root->base.hname, hats[0]);
 653                         target = name;
 654                         /* released below */
 655                         hat = aa_new_null_profile(profile, 1);
 656                         if (!hat) {
 657                                 info = "failed null profile create";
 658                                 error = -ENOMEM;
 659                                 goto audit;
 660                         }
 661                 } else {
 662                         target = hat->base.hname;
 663                         if (!PROFILE_IS_HAT(hat)) {
 664                                 info = "target not hat";
 665                                 error = -EPERM;
 666                                 goto audit;
 667                         }
 668                 }
 669
 670                 error = may_change_ptraced_domain(current, hat);
 671                 if (error) {
 672                         info = "ptraced";
 673                         error = -EPERM;
 674                         goto audit;
 675                 }
 676
 677                 if (!permtest) {
 678                         error = aa_set_current_hat(hat, token);
 679                         if (error == -EACCES)
 680                                 /* kill task in case of brute force attacks */
 681                                 perms.kill = AA_MAY_CHANGEHAT;
 682                         else if (name && !error)
 683                                 /* reset error for learning of new hats */
 684                                 error = -ENOENT;
 685                 }
 686         } else if (previous_profile) {
 687                 /* Return to saved profile.  Kill task if restore fails
 688                  * to avoid brute force attacks
 689                  */
 690                 target = previous_profile->base.hname;
 691                 error = aa_restore_previous_profile(token);
 692                 perms.kill = AA_MAY_CHANGEHAT;
 693         } else
 694                 /* ignore restores when there is no saved profile */
 695                 goto out;
 696
 697 audit:
 698         if (!permtest)
 699                 error = aa_audit_file(profile, &perms, GFP_KERNEL,
 700                                       OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
 701                                       target, 0, info, error);
 702
 703 out:
 704         aa_put_profile(hat);
 705         kfree(name);
 706         put_cred(cred);
 707
 708         return error;
 709 }
 710
 711 /**
 712  * aa_change_profile - perform a one-way profile transition
 713  * @ns_name: name of the profile namespace to change to (MAYBE NULL)
 714  * @hname: name of profile to change to (MAYBE NULL)
 715  * @onexec: whether this transition is to take place immediately or at exec
 716  * @permtest: true if this is just a permission test
 717  *
 718  * Change to new profile @name.  Unlike with hats, there is no way
 719  * to change back.  If @name isn't specified the current profile name is
 720  * used.
 721  * If @onexec then the transition is delayed until
 722  * the next exec.
 723  *
 724  * Returns %0 on success, error otherwise.
 725  */
 726 int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
 727                       bool permtest)
 728 {
 729         const struct cred *cred;
 730         struct aa_task_cxt *cxt;
 731         struct aa_profile *profile, *target = NULL;
 732         struct aa_namespace *ns = NULL;
 733         struct file_perms perms = {};
 734         const char *name = NULL, *info = NULL;
 735         int op, error = 0;
 736         u32 request;
 737
 738         if (!hname && !ns_name)
 739                 return -EINVAL;
 740
 741         if (onexec) {
 742                 request = AA_MAY_ONEXEC;
 743                 op = OP_CHANGE_ONEXEC;
 744         } else {
 745                 request = AA_MAY_CHANGE_PROFILE;
 746                 op = OP_CHANGE_PROFILE;
 747         }
 748
 749         cred = get_current_cred();
 750         cxt = cred->security;
 751         profile = aa_cred_profile(cred);
 752
 753         if (ns_name) {
 754                 /* released below */
 755                 ns = aa_find_namespace(profile->ns, ns_name);
 756                 if (!ns) {
 757                         /* we don't create new namespace in complain mode */
 758                         name = ns_name;
 759                         info = "namespace not found";
 760                         error = -ENOENT;
 761                         goto audit;
 762                 }
 763         } else
 764                 /* released below */
 765                 ns = aa_get_namespace(profile->ns);
 766
 767         /* if the name was not specified, use the name of the current profile */
 768         if (!hname) {
 769                 if (unconfined(profile))
 770                         hname = ns->unconfined->base.hname;
 771                 else
 772                         hname = profile->base.hname;
 773         }
 774
 775         perms = change_profile_perms(profile, ns, hname, request,
 776                                      profile->file.start);
 777         if (!(perms.allow & request)) {
 778                 error = -EACCES;
 779                 goto audit;
 780         }
 781
 782         /* released below */
 783         target = aa_lookup_profile(ns, hname);
 784         if (!target) {
 785                 info = "profile not found";
 786                 error = -ENOENT;
 787                 if (permtest || !COMPLAIN_MODE(profile))
 788                         goto audit;
 789                 /* released below */
 790                 target = aa_new_null_profile(profile, 0);
 791                 if (!target) {
 792                         info = "failed null profile create";
 793                         error = -ENOMEM;
 794                         goto audit;
 795                 }
 796         }
 797
 798         /* check if tracing task is allowed to trace target domain */
 799         error = may_change_ptraced_domain(current, target);
 800         if (error) {
 801                 info = "ptrace prevents transition";
 802                 goto audit;
 803         }
 804
 805         if (permtest)
 806                 goto audit;
 807
 808         if (onexec)
 809                 error = aa_set_current_onexec(target);
 810         else
 811                 error = aa_replace_current_profile(target);
 812
 813 audit:
 814         if (!permtest)
 815                 error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
 816                                       name, hname, 0, info, error);
 817
 818         aa_put_namespace(ns);
 819         aa_put_profile(target);
 820         put_cred(cred);
 821
 822         return error;
 823 }