linux/security/apparmor/domain.c
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   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 */
  37void 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 */
  61static 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
  83out:
  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 */
 101static 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 */
 145static 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 */
 179static 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 */
 212static 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
 233static 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 */
 245static 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 */
 306static 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 */
 343int 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_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
 376                             &name, &info);
 377        if (error) {
 378                if (profile->flags &
 379                    (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED))
 380                        error = 0;
 381                name = bprm->filename;
 382                goto audit;
 383        }
 384
 385        /* Test for onexec first as onexec directives override other
 386         * x transitions.
 387         */
 388        if (unconfined(profile)) {
 389                /* unconfined task */
 390                if (cxt->onexec)
 391                        /* change_profile on exec already been granted */
 392                        new_profile = aa_get_profile(cxt->onexec);
 393                else
 394                        new_profile = find_attach(ns, &ns->base.profiles, name);
 395                if (!new_profile)
 396                        goto cleanup;
 397                /*
 398                 * NOTE: Domain transitions from unconfined are allowed
 399                 * even when no_new_privs is set because this aways results
 400                 * in a further reduction of permissions.
 401                 */
 402                goto apply;
 403        }
 404
 405        /* find exec permissions for name */
 406        state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
 407        if (cxt->onexec) {
 408                struct file_perms cp;
 409                info = "change_profile onexec";
 410                if (!(perms.allow & AA_MAY_ONEXEC))
 411                        goto audit;
 412
 413                /* test if this exec can be paired with change_profile onexec.
 414                 * onexec permission is linked to exec with a standard pairing
 415                 * exec\0change_profile
 416                 */
 417                state = aa_dfa_null_transition(profile->file.dfa, state);
 418                cp = change_profile_perms(profile, cxt->onexec->ns,
 419                                          cxt->onexec->base.name,
 420                                          AA_MAY_ONEXEC, state);
 421
 422                if (!(cp.allow & AA_MAY_ONEXEC))
 423                        goto audit;
 424                new_profile = aa_get_profile(aa_newest_version(cxt->onexec));
 425                goto apply;
 426        }
 427
 428        if (perms.allow & MAY_EXEC) {
 429                /* exec permission determine how to transition */
 430                new_profile = x_to_profile(profile, name, perms.xindex);
 431                if (!new_profile) {
 432                        if (perms.xindex & AA_X_INHERIT) {
 433                                /* (p|c|n)ix - don't change profile but do
 434                                 * use the newest version, which was picked
 435                                 * up above when getting profile
 436                                 */
 437                                info = "ix fallback";
 438                                new_profile = aa_get_profile(profile);
 439                                goto x_clear;
 440                        } else if (perms.xindex & AA_X_UNCONFINED) {
 441                                new_profile = aa_get_profile(ns->unconfined);
 442                                info = "ux fallback";
 443                        } else {
 444                                error = -ENOENT;
 445                                info = "profile not found";
 446                        }
 447                }
 448        } else if (COMPLAIN_MODE(profile)) {
 449                /* no exec permission - are we in learning mode */
 450                new_profile = aa_new_null_profile(profile, 0);
 451                if (!new_profile) {
 452                        error = -ENOMEM;
 453                        info = "could not create null profile";
 454                } else {
 455                        error = -EACCES;
 456                        target = new_profile->base.hname;
 457                }
 458                perms.xindex |= AA_X_UNSAFE;
 459        } else
 460                /* fail exec */
 461                error = -EACCES;
 462
 463        /*
 464         * Policy has specified a domain transition, if no_new_privs then
 465         * fail the exec.
 466         */
 467        if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
 468                aa_put_profile(new_profile);
 469                error = -EPERM;
 470                goto cleanup;
 471        }
 472
 473        if (!new_profile)
 474                goto audit;
 475
 476        if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 477                /* FIXME: currently don't mediate shared state */
 478                ;
 479        }
 480
 481        if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
 482                error = may_change_ptraced_domain(current, new_profile);
 483                if (error) {
 484                        aa_put_profile(new_profile);
 485                        goto audit;
 486                }
 487        }
 488
 489        /* Determine if secure exec is needed.
 490         * Can be at this point for the following reasons:
 491         * 1. unconfined switching to confined
 492         * 2. confined switching to different confinement
 493         * 3. confined switching to unconfined
 494         *
 495         * Cases 2 and 3 are marked as requiring secure exec
 496         * (unless policy specified "unsafe exec")
 497         *
 498         * bprm->unsafe is used to cache the AA_X_UNSAFE permission
 499         * to avoid having to recompute in secureexec
 500         */
 501        if (!(perms.xindex & AA_X_UNSAFE)) {
 502                AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
 503                         name, new_profile->base.hname);
 504                bprm->unsafe |= AA_SECURE_X_NEEDED;
 505        }
 506apply:
 507        target = new_profile->base.hname;
 508        /* when transitioning profiles clear unsafe personality bits */
 509        bprm->per_clear |= PER_CLEAR_ON_SETID;
 510
 511x_clear:
 512        aa_put_profile(cxt->profile);
 513        /* transfer new profile reference will be released when cxt is freed */
 514        cxt->profile = new_profile;
 515
 516        /* clear out all temporary/transitional state from the context */
 517        aa_put_profile(cxt->previous);
 518        aa_put_profile(cxt->onexec);
 519        cxt->previous = NULL;
 520        cxt->onexec = NULL;
 521        cxt->token = 0;
 522
 523audit:
 524        error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
 525                              name, target, cond.uid, info, error);
 526
 527cleanup:
 528        aa_put_profile(profile);
 529        kfree(buffer);
 530
 531        return error;
 532}
 533
 534/**
 535 * apparmor_bprm_secureexec - determine if secureexec is needed
 536 * @bprm: binprm for exec  (NOT NULL)
 537 *
 538 * Returns: %1 if secureexec is needed else %0
 539 */
 540int apparmor_bprm_secureexec(struct linux_binprm *bprm)
 541{
 542        int ret = cap_bprm_secureexec(bprm);
 543
 544        /* the decision to use secure exec is computed in set_creds
 545         * and stored in bprm->unsafe.
 546         */
 547        if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
 548                ret = 1;
 549
 550        return ret;
 551}
 552
 553/**
 554 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
 555 * @bprm: binprm for the exec  (NOT NULL)
 556 */
 557void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
 558{
 559        struct aa_profile *profile = __aa_current_profile();
 560        struct aa_task_cxt *new_cxt = bprm->cred->security;
 561
 562        /* bail out if unconfined or not changing profile */
 563        if ((new_cxt->profile == profile) ||
 564            (unconfined(new_cxt->profile)))
 565                return;
 566
 567        current->pdeath_signal = 0;
 568
 569        /* reset soft limits and set hard limits for the new profile */
 570        __aa_transition_rlimits(profile, new_cxt->profile);
 571}
 572
 573/**
 574 * apparmor_bprm_commited_cred - do cleanup after new creds committed
 575 * @bprm: binprm for the exec  (NOT NULL)
 576 */
 577void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 578{
 579        /* TODO: cleanup signals - ipc mediation */
 580        return;
 581}
 582
 583/*
 584 * Functions for self directed profile change
 585 */
 586
 587/**
 588 * new_compound_name - create an hname with @n2 appended to @n1
 589 * @n1: base of hname  (NOT NULL)
 590 * @n2: name to append (NOT NULL)
 591 *
 592 * Returns: new name or NULL on error
 593 */
 594static char *new_compound_name(const char *n1, const char *n2)
 595{
 596        char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
 597        if (name)
 598                sprintf(name, "%s//%s", n1, n2);
 599        return name;
 600}
 601
 602/**
 603 * aa_change_hat - change hat to/from subprofile
 604 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
 605 * @count: number of hat names in @hats
 606 * @token: magic value to validate the hat change
 607 * @permtest: true if this is just a permission test
 608 *
 609 * Change to the first profile specified in @hats that exists, and store
 610 * the @hat_magic in the current task context.  If the count == 0 and the
 611 * @token matches that stored in the current task context, return to the
 612 * top level profile.
 613 *
 614 * Returns %0 on success, error otherwise.
 615 */
 616int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
 617{
 618        const struct cred *cred;
 619        struct aa_task_cxt *cxt;
 620        struct aa_profile *profile, *previous_profile, *hat = NULL;
 621        char *name = NULL;
 622        int i;
 623        struct file_perms perms = {};
 624        const char *target = NULL, *info = NULL;
 625        int error = 0;
 626
 627        /*
 628         * Fail explicitly requested domain transitions if no_new_privs.
 629         * There is no exception for unconfined as change_hat is not
 630         * available.
 631         */
 632        if (current->no_new_privs)
 633                return -EPERM;
 634
 635        /* released below */
 636        cred = get_current_cred();
 637        cxt = cred->security;
 638        profile = aa_cred_profile(cred);
 639        previous_profile = cxt->previous;
 640
 641        if (unconfined(profile)) {
 642                info = "unconfined";
 643                error = -EPERM;
 644                goto audit;
 645        }
 646
 647        if (count) {
 648                /* attempting to change into a new hat or switch to a sibling */
 649                struct aa_profile *root;
 650                root = PROFILE_IS_HAT(profile) ? profile->parent : profile;
 651
 652                /* find first matching hat */
 653                for (i = 0; i < count && !hat; i++)
 654                        /* released below */
 655                        hat = aa_find_child(root, hats[i]);
 656                if (!hat) {
 657                        if (!COMPLAIN_MODE(root) || permtest) {
 658                                if (list_empty(&root->base.profiles))
 659                                        error = -ECHILD;
 660                                else
 661                                        error = -ENOENT;
 662                                goto out;
 663                        }
 664
 665                        /*
 666                         * In complain mode and failed to match any hats.
 667                         * Audit the failure is based off of the first hat
 668                         * supplied.  This is done due how userspace
 669                         * interacts with change_hat.
 670                         *
 671                         * TODO: Add logging of all failed hats
 672                         */
 673
 674                        /* freed below */
 675                        name = new_compound_name(root->base.hname, hats[0]);
 676                        target = name;
 677                        /* released below */
 678                        hat = aa_new_null_profile(profile, 1);
 679                        if (!hat) {
 680                                info = "failed null profile create";
 681                                error = -ENOMEM;
 682                                goto audit;
 683                        }
 684                } else {
 685                        target = hat->base.hname;
 686                        if (!PROFILE_IS_HAT(hat)) {
 687                                info = "target not hat";
 688                                error = -EPERM;
 689                                goto audit;
 690                        }
 691                }
 692
 693                error = may_change_ptraced_domain(current, hat);
 694                if (error) {
 695                        info = "ptraced";
 696                        error = -EPERM;
 697                        goto audit;
 698                }
 699
 700                if (!permtest) {
 701                        error = aa_set_current_hat(hat, token);
 702                        if (error == -EACCES)
 703                                /* kill task in case of brute force attacks */
 704                                perms.kill = AA_MAY_CHANGEHAT;
 705                        else if (name && !error)
 706                                /* reset error for learning of new hats */
 707                                error = -ENOENT;
 708                }
 709        } else if (previous_profile) {
 710                /* Return to saved profile.  Kill task if restore fails
 711                 * to avoid brute force attacks
 712                 */
 713                target = previous_profile->base.hname;
 714                error = aa_restore_previous_profile(token);
 715                perms.kill = AA_MAY_CHANGEHAT;
 716        } else
 717                /* ignore restores when there is no saved profile */
 718                goto out;
 719
 720audit:
 721        if (!permtest)
 722                error = aa_audit_file(profile, &perms, GFP_KERNEL,
 723                                      OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
 724                                      target, 0, info, error);
 725
 726out:
 727        aa_put_profile(hat);
 728        kfree(name);
 729        put_cred(cred);
 730
 731        return error;
 732}
 733
 734/**
 735 * aa_change_profile - perform a one-way profile transition
 736 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
 737 * @hname: name of profile to change to (MAYBE NULL)
 738 * @onexec: whether this transition is to take place immediately or at exec
 739 * @permtest: true if this is just a permission test
 740 *
 741 * Change to new profile @name.  Unlike with hats, there is no way
 742 * to change back.  If @name isn't specified the current profile name is
 743 * used.
 744 * If @onexec then the transition is delayed until
 745 * the next exec.
 746 *
 747 * Returns %0 on success, error otherwise.
 748 */
 749int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
 750                      bool permtest)
 751{
 752        const struct cred *cred;
 753        struct aa_task_cxt *cxt;
 754        struct aa_profile *profile, *target = NULL;
 755        struct aa_namespace *ns = NULL;
 756        struct file_perms perms = {};
 757        const char *name = NULL, *info = NULL;
 758        int op, error = 0;
 759        u32 request;
 760
 761        if (!hname && !ns_name)
 762                return -EINVAL;
 763
 764        if (onexec) {
 765                request = AA_MAY_ONEXEC;
 766                op = OP_CHANGE_ONEXEC;
 767        } else {
 768                request = AA_MAY_CHANGE_PROFILE;
 769                op = OP_CHANGE_PROFILE;
 770        }
 771
 772        cred = get_current_cred();
 773        cxt = cred->security;
 774        profile = aa_cred_profile(cred);
 775
 776        /*
 777         * Fail explicitly requested domain transitions if no_new_privs
 778         * and not unconfined.
 779         * Domain transitions from unconfined are allowed even when
 780         * no_new_privs is set because this aways results in a reduction
 781         * of permissions.
 782         */
 783        if (current->no_new_privs && !unconfined(profile)) {
 784                put_cred(cred);
 785                return -EPERM;
 786        }
 787
 788        if (ns_name) {
 789                /* released below */
 790                ns = aa_find_namespace(profile->ns, ns_name);
 791                if (!ns) {
 792                        /* we don't create new namespace in complain mode */
 793                        name = ns_name;
 794                        info = "namespace not found";
 795                        error = -ENOENT;
 796                        goto audit;
 797                }
 798        } else
 799                /* released below */
 800                ns = aa_get_namespace(profile->ns);
 801
 802        /* if the name was not specified, use the name of the current profile */
 803        if (!hname) {
 804                if (unconfined(profile))
 805                        hname = ns->unconfined->base.hname;
 806                else
 807                        hname = profile->base.hname;
 808        }
 809
 810        perms = change_profile_perms(profile, ns, hname, request,
 811                                     profile->file.start);
 812        if (!(perms.allow & request)) {
 813                error = -EACCES;
 814                goto audit;
 815        }
 816
 817        /* released below */
 818        target = aa_lookup_profile(ns, hname);
 819        if (!target) {
 820                info = "profile not found";
 821                error = -ENOENT;
 822                if (permtest || !COMPLAIN_MODE(profile))
 823                        goto audit;
 824                /* released below */
 825                target = aa_new_null_profile(profile, 0);
 826                if (!target) {
 827                        info = "failed null profile create";
 828                        error = -ENOMEM;
 829                        goto audit;
 830                }
 831        }
 832
 833        /* check if tracing task is allowed to trace target domain */
 834        error = may_change_ptraced_domain(current, target);
 835        if (error) {
 836                info = "ptrace prevents transition";
 837                goto audit;
 838        }
 839
 840        if (permtest)
 841                goto audit;
 842
 843        if (onexec)
 844                error = aa_set_current_onexec(target);
 845        else
 846                error = aa_replace_current_profile(target);
 847
 848audit:
 849        if (!permtest)
 850                error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
 851                                      name, hname, 0, info, error);
 852
 853        aa_put_namespace(ns);
 854        aa_put_profile(target);
 855        put_cred(cred);
 856
 857        return error;
 858}
 859
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