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/fs.h>
  13#include <linux/file.h>
  14#include <linux/mount.h>
  15#include <linux/syscalls.h>
  16#include <linux/personality.h>
  17#include <linux/xattr.h>
  18#include <linux/user_namespace.h>
  19
  20#include "include/audit.h"
  21#include "include/apparmorfs.h"
  22#include "include/cred.h"
  23#include "include/domain.h"
  24#include "include/file.h"
  25#include "include/ipc.h"
  26#include "include/match.h"
  27#include "include/path.h"
  28#include "include/policy.h"
  29#include "include/policy_ns.h"
  30
  31/**
  32 * may_change_ptraced_domain - check if can change profile on ptraced task
  33 * @to_cred: cred of task changing domain
  34 * @to_label: profile to change to  (NOT NULL)
  35 * @info: message if there is an error
  36 *
  37 * Check if current is ptraced and if so if the tracing task is allowed
  38 * to trace the new domain
  39 *
  40 * Returns: %0 or error if change not allowed
  41 */
  42static int may_change_ptraced_domain(const struct cred *to_cred,
  43				     struct aa_label *to_label,
  44				     const char **info)
  45{
  46	struct task_struct *tracer;
  47	struct aa_label *tracerl = NULL;
  48	const struct cred *tracer_cred = NULL;
  49
  50	int error = 0;
  51
  52	rcu_read_lock();
  53	tracer = ptrace_parent(current);
  54	if (tracer) {
  55		/* released below */
  56		tracerl = aa_get_task_label(tracer);
  57		tracer_cred = get_task_cred(tracer);
  58	}
  59	/* not ptraced */
  60	if (!tracer || unconfined(tracerl))
  61		goto out;
  62
  63	error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
  64			      PTRACE_MODE_ATTACH);
  65
  66out:
  67	rcu_read_unlock();
  68	aa_put_label(tracerl);
  69	put_cred(tracer_cred);
  70
  71	if (error)
  72		*info = "ptrace prevents transition";
  73	return error;
  74}
  75
  76/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
  77 * specifically this is an exact copy of aa_label_match except
  78 * aa_compute_perms is replaced with aa_compute_fperms
  79 * and policy->dfa with file->dfa
  80 ****/
  81/* match a profile and its associated ns component if needed
  82 * Assumes visibility test has already been done.
  83 * If a subns profile is not to be matched should be prescreened with
  84 * visibility test.
  85 */
  86static inline aa_state_t match_component(struct aa_profile *profile,
  87					 struct aa_profile *tp,
  88					 bool stack, aa_state_t state)
  89{
  90	struct aa_ruleset *rules = list_first_entry(&profile->rules,
  91						    typeof(*rules), list);
  92	const char *ns_name;
  93
  94	if (stack)
  95		state = aa_dfa_match(rules->file->dfa, state, "&");
  96	if (profile->ns == tp->ns)
  97		return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
  98
  99	/* try matching with namespace name and then profile */
 100	ns_name = aa_ns_name(profile->ns, tp->ns, true);
 101	state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
 102	state = aa_dfa_match(rules->file->dfa, state, ns_name);
 103	state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
 104	return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
 105}
 106
 107/**
 108 * label_compound_match - find perms for full compound label
 109 * @profile: profile to find perms for
 110 * @label: label to check access permissions for
 111 * @stack: whether this is a stacking request
 112 * @state: state to start match in
 113 * @subns: whether to do permission checks on components in a subns
 114 * @request: permissions to request
 115 * @perms: perms struct to set
 116 *
 117 * Returns: 0 on success else ERROR
 118 *
 119 * For the label A//&B//&C this does the perm match for A//&B//&C
 120 * @perms should be preinitialized with allperms OR a previous permission
 121 *        check to be stacked.
 122 */
 123static int label_compound_match(struct aa_profile *profile,
 124				struct aa_label *label, bool stack,
 125				aa_state_t state, bool subns, u32 request,
 126				struct aa_perms *perms)
 127{
 128	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 129						    typeof(*rules), list);
 130	struct aa_profile *tp;
 131	struct label_it i;
 132	struct path_cond cond = { };
 133
 134	/* find first subcomponent that is visible */
 135	label_for_each(i, label, tp) {
 136		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 137			continue;
 138		state = match_component(profile, tp, stack, state);
 139		if (!state)
 140			goto fail;
 141		goto next;
 142	}
 143
 144	/* no component visible */
 145	*perms = allperms;
 146	return 0;
 147
 148next:
 149	label_for_each_cont(i, label, tp) {
 150		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 151			continue;
 152		state = aa_dfa_match(rules->file->dfa, state, "//&");
 153		state = match_component(profile, tp, false, state);
 154		if (!state)
 155			goto fail;
 156	}
 157	*perms = *(aa_lookup_fperms(rules->file, state, &cond));
 158	aa_apply_modes_to_perms(profile, perms);
 159	if ((perms->allow & request) != request)
 160		return -EACCES;
 161
 162	return 0;
 163
 164fail:
 165	*perms = nullperms;
 166	return -EACCES;
 167}
 168
 169/**
 170 * label_components_match - find perms for all subcomponents of a label
 171 * @profile: profile to find perms for
 172 * @label: label to check access permissions for
 173 * @stack: whether this is a stacking request
 174 * @start: state to start match in
 175 * @subns: whether to do permission checks on components in a subns
 176 * @request: permissions to request
 177 * @perms: an initialized perms struct to add accumulation to
 178 *
 179 * Returns: 0 on success else ERROR
 180 *
 181 * For the label A//&B//&C this does the perm match for each of A and B and C
 182 * @perms should be preinitialized with allperms OR a previous permission
 183 *        check to be stacked.
 184 */
 185static int label_components_match(struct aa_profile *profile,
 186				  struct aa_label *label, bool stack,
 187				  aa_state_t start, bool subns, u32 request,
 188				  struct aa_perms *perms)
 189{
 190	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 191						    typeof(*rules), list);
 192	struct aa_profile *tp;
 193	struct label_it i;
 194	struct aa_perms tmp;
 195	struct path_cond cond = { };
 196	aa_state_t state = 0;
 197
 198	/* find first subcomponent to test */
 199	label_for_each(i, label, tp) {
 200		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 201			continue;
 202		state = match_component(profile, tp, stack, start);
 203		if (!state)
 204			goto fail;
 205		goto next;
 206	}
 207
 208	/* no subcomponents visible - no change in perms */
 209	return 0;
 210
 211next:
 212	tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 213	aa_apply_modes_to_perms(profile, &tmp);
 214	aa_perms_accum(perms, &tmp);
 215	label_for_each_cont(i, label, tp) {
 216		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 217			continue;
 218		state = match_component(profile, tp, stack, start);
 219		if (!state)
 220			goto fail;
 221		tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 222		aa_apply_modes_to_perms(profile, &tmp);
 223		aa_perms_accum(perms, &tmp);
 224	}
 225
 226	if ((perms->allow & request) != request)
 227		return -EACCES;
 228
 229	return 0;
 230
 231fail:
 232	*perms = nullperms;
 233	return -EACCES;
 234}
 235
 236/**
 237 * label_match - do a multi-component label match
 238 * @profile: profile to match against (NOT NULL)
 239 * @label: label to match (NOT NULL)
 240 * @stack: whether this is a stacking request
 241 * @state: state to start in
 242 * @subns: whether to match subns components
 243 * @request: permission request
 244 * @perms: Returns computed perms (NOT NULL)
 245 *
 246 * Returns: the state the match finished in, may be the none matching state
 247 */
 248static int label_match(struct aa_profile *profile, struct aa_label *label,
 249		       bool stack, aa_state_t state, bool subns, u32 request,
 250		       struct aa_perms *perms)
 251{
 252	int error;
 253
 254	*perms = nullperms;
 255	error = label_compound_match(profile, label, stack, state, subns,
 256				     request, perms);
 257	if (!error)
 258		return error;
 259
 260	*perms = allperms;
 261	return label_components_match(profile, label, stack, state, subns,
 262				      request, perms);
 263}
 264
 265/******* end TODO: dedup *****/
 266
 267/**
 268 * change_profile_perms - find permissions for change_profile
 269 * @profile: the current profile  (NOT NULL)
 270 * @target: label to transition to (NOT NULL)
 271 * @stack: whether this is a stacking request
 272 * @request: requested perms
 273 * @start: state to start matching in
 274 * @perms: Returns computed perms (NOT NULL)
 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 */
 282static 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 */
 305static 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
 362out:
 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 */
 384static 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();
 396restart:
 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
 492out:
 493	candidate = aa_get_newest_profile(candidate);
 494	rcu_read_unlock();
 495
 496	return &candidate->label;
 497}
 498
 499static 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 */
 512struct 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 * @info: info message if there was an error (NOT NULL)
 556 *
 557 * find label for a transition index
 558 *
 559 * Returns: refcounted label or NULL if not found available
 560 */
 561static struct aa_label *x_to_label(struct aa_profile *profile,
 562				   const struct linux_binprm *bprm,
 563				   const char *name, u32 xindex,
 564				   const char **lookupname,
 565				   const char **info)
 566{
 567	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 568						    typeof(*rules), list);
 569	struct aa_label *new = NULL;
 570	struct aa_ns *ns = profile->ns;
 571	u32 xtype = xindex & AA_X_TYPE_MASK;
 572	const char *stack = NULL;
 573
 574	switch (xtype) {
 575	case AA_X_NONE:
 576		/* fail exec unless ix || ux fallback - handled by caller */
 577		*lookupname = NULL;
 578		break;
 579	case AA_X_TABLE:
 580		/* TODO: fix when perm mapping done at unload */
 581		stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
 582		if (*stack != '&') {
 583			/* released by caller */
 584			new = x_table_lookup(profile, xindex, lookupname);
 585			stack = NULL;
 586			break;
 587		}
 588		fallthrough;	/* to X_NAME */
 589	case AA_X_NAME:
 590		if (xindex & AA_X_CHILD)
 591			/* released by caller */
 592			new = find_attach(bprm, ns, &profile->base.profiles,
 593					  name, info);
 594		else
 595			/* released by caller */
 596			new = find_attach(bprm, ns, &ns->base.profiles,
 597					  name, info);
 598		*lookupname = name;
 599		break;
 600	}
 601
 602	if (!new) {
 603		if (xindex & AA_X_INHERIT) {
 604			/* (p|c|n)ix - don't change profile but do
 605			 * use the newest version
 606			 */
 607			*info = "ix fallback";
 608			/* no profile && no error */
 609			new = aa_get_newest_label(&profile->label);
 610		} else if (xindex & AA_X_UNCONFINED) {
 611			new = aa_get_newest_label(ns_unconfined(profile->ns));
 612			*info = "ux fallback";
 613		}
 614	}
 615
 616	if (new && stack) {
 617		/* base the stack on post domain transition */
 618		struct aa_label *base = new;
 619
 620		new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
 621		if (IS_ERR(new))
 622			new = NULL;
 623		aa_put_label(base);
 624	}
 625
 626	/* released by caller */
 627	return new;
 628}
 629
 630static struct aa_label *profile_transition(const struct cred *subj_cred,
 631					   struct aa_profile *profile,
 632					   const struct linux_binprm *bprm,
 633					   char *buffer, struct path_cond *cond,
 634					   bool *secure_exec)
 635{
 636	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 637						    typeof(*rules), list);
 638	struct aa_label *new = NULL;
 639	struct aa_profile *new_profile = NULL;
 640	const char *info = NULL, *name = NULL, *target = NULL;
 641	aa_state_t state = rules->file->start[AA_CLASS_FILE];
 642	struct aa_perms perms = {};
 643	bool nonewprivs = false;
 644	int error = 0;
 645
 646	AA_BUG(!profile);
 647	AA_BUG(!bprm);
 648	AA_BUG(!buffer);
 649
 650	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 651			     &name, &info, profile->disconnected);
 652	if (error) {
 653		if (profile_unconfined(profile) ||
 654		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 655			AA_DEBUG("name lookup ix on error");
 656			error = 0;
 657			new = aa_get_newest_label(&profile->label);
 658		}
 659		name = bprm->filename;
 660		goto audit;
 661	}
 662
 663	if (profile_unconfined(profile)) {
 664		new = find_attach(bprm, profile->ns,
 665				  &profile->ns->base.profiles, name, &info);
 666		if (new) {
 667			AA_DEBUG("unconfined attached to new label");
 668			return new;
 669		}
 670		AA_DEBUG("unconfined exec no attachment");
 671		return aa_get_newest_label(&profile->label);
 672	}
 673
 674	/* find exec permissions for name */
 675	state = aa_str_perms(rules->file, state, name, cond, &perms);
 676	if (perms.allow & MAY_EXEC) {
 677		/* exec permission determine how to transition */
 678		new = x_to_label(profile, bprm, name, perms.xindex, &target,
 679				 &info);
 680		if (new && new->proxy == profile->label.proxy && info) {
 681			/* hack ix fallback - improve how this is detected */
 682			goto audit;
 683		} else if (!new) {
 
 684			info = "profile transition not found";
 685			/* remove MAY_EXEC to audit as failure or complaint */
 686			perms.allow &= ~MAY_EXEC;
 687			if (COMPLAIN_MODE(profile)) {
 688				/* create null profile instead of failing */
 689				goto create_learning_profile;
 690			}
 691			error = -EACCES;
 692		}
 693	} else if (COMPLAIN_MODE(profile)) {
 694create_learning_profile:
 695		/* no exec permission - learning mode */
 
 
 696		new_profile = aa_new_learning_profile(profile, false, name,
 697						      GFP_KERNEL);
 698		if (!new_profile) {
 699			error = -ENOMEM;
 700			info = "could not create null profile";
 701		} else {
 702			error = -EACCES;
 703			new = &new_profile->label;
 704		}
 705		perms.xindex |= AA_X_UNSAFE;
 706	} else
 707		/* fail exec */
 708		error = -EACCES;
 709
 710	if (!new)
 711		goto audit;
 712
 713
 714	if (!(perms.xindex & AA_X_UNSAFE)) {
 715		if (DEBUG_ON) {
 716			dbg_printk("apparmor: setting AT_SECURE for %s profile=",
 717				   name);
 718			aa_label_printk(new, GFP_KERNEL);
 719			dbg_printk("\n");
 720		}
 721		*secure_exec = true;
 722	}
 723
 724audit:
 725	aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
 726		      target, new,
 727		      cond->uid, info, error);
 728	if (!new || nonewprivs) {
 729		aa_put_label(new);
 730		return ERR_PTR(error);
 731	}
 732
 733	return new;
 734}
 735
 736static int profile_onexec(const struct cred *subj_cred,
 737			  struct aa_profile *profile, struct aa_label *onexec,
 738			  bool stack, const struct linux_binprm *bprm,
 739			  char *buffer, struct path_cond *cond,
 740			  bool *secure_exec)
 741{
 742	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 743						    typeof(*rules), list);
 744	aa_state_t state = rules->file->start[AA_CLASS_FILE];
 745	struct aa_perms perms = {};
 746	const char *xname = NULL, *info = "change_profile onexec";
 747	int error = -EACCES;
 748
 749	AA_BUG(!profile);
 750	AA_BUG(!onexec);
 751	AA_BUG(!bprm);
 752	AA_BUG(!buffer);
 753
 754	if (profile_unconfined(profile)) {
 755		/* change_profile on exec already granted */
 756		/*
 757		 * NOTE: Domain transitions from unconfined are allowed
 758		 * even when no_new_privs is set because this aways results
 759		 * in a further reduction of permissions.
 760		 */
 761		return 0;
 762	}
 763
 764	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 765			     &xname, &info, profile->disconnected);
 766	if (error) {
 767		if (profile_unconfined(profile) ||
 768		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 769			AA_DEBUG("name lookup ix on error");
 770			error = 0;
 771		}
 772		xname = bprm->filename;
 773		goto audit;
 774	}
 775
 776	/* find exec permissions for name */
 777	state = aa_str_perms(rules->file, state, xname, cond, &perms);
 778	if (!(perms.allow & AA_MAY_ONEXEC)) {
 779		info = "no change_onexec valid for executable";
 780		goto audit;
 781	}
 782	/* test if this exec can be paired with change_profile onexec.
 783	 * onexec permission is linked to exec with a standard pairing
 784	 * exec\0change_profile
 785	 */
 786	state = aa_dfa_null_transition(rules->file->dfa, state);
 787	error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
 788				     state, &perms);
 789	if (error) {
 790		perms.allow &= ~AA_MAY_ONEXEC;
 791		goto audit;
 792	}
 793
 794	if (!(perms.xindex & AA_X_UNSAFE)) {
 795		if (DEBUG_ON) {
 796			dbg_printk("apparmor: setting AT_SECURE for %s label=",
 797				   xname);
 798			aa_label_printk(onexec, GFP_KERNEL);
 799			dbg_printk("\n");
 800		}
 801		*secure_exec = true;
 802	}
 803
 804audit:
 805	return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
 806			     AA_MAY_ONEXEC, xname,
 807			     NULL, onexec, cond->uid, info, error);
 808}
 809
 810/* ensure none ns domain transitions are correctly applied with onexec */
 811
 812static struct aa_label *handle_onexec(const struct cred *subj_cred,
 813				      struct aa_label *label,
 814				      struct aa_label *onexec, bool stack,
 815				      const struct linux_binprm *bprm,
 816				      char *buffer, struct path_cond *cond,
 817				      bool *unsafe)
 818{
 819	struct aa_profile *profile;
 820	struct aa_label *new;
 821	int error;
 822
 823	AA_BUG(!label);
 824	AA_BUG(!onexec);
 825	AA_BUG(!bprm);
 826	AA_BUG(!buffer);
 827
 828	/* TODO: determine how much we want to loosen this */
 829	error = fn_for_each_in_ns(label, profile,
 830			profile_onexec(subj_cred, profile, onexec, stack,
 831				       bprm, buffer, cond, unsafe));
 832	if (error)
 833		return ERR_PTR(error);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 834
 835	new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 836			stack ? aa_label_merge(&profile->label, onexec,
 837					       GFP_KERNEL)
 838			      : aa_get_newest_label(onexec),
 839			profile_transition(subj_cred, profile, bprm,
 840					   buffer, cond, unsafe));
 841	if (new)
 842		return new;
 843
 844	/* TODO: get rid of GLOBAL_ROOT_UID */
 845	error = fn_for_each_in_ns(label, profile,
 846			aa_audit_file(subj_cred, profile, &nullperms,
 847				      OP_CHANGE_ONEXEC,
 848				      AA_MAY_ONEXEC, bprm->filename, NULL,
 849				      onexec, GLOBAL_ROOT_UID,
 850				      "failed to build target label", -ENOMEM));
 851	return ERR_PTR(error);
 852}
 853
 854/**
 855 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
 856 * @bprm: binprm for the exec  (NOT NULL)
 857 *
 858 * Returns: %0 or error on failure
 859 *
 860 * TODO: once the other paths are done see if we can't refactor into a fn
 861 */
 862int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 863{
 864	struct aa_task_ctx *ctx;
 865	struct aa_label *label, *new = NULL;
 866	const struct cred *subj_cred;
 867	struct aa_profile *profile;
 868	char *buffer = NULL;
 869	const char *info = NULL;
 870	int error = 0;
 871	bool unsafe = false;
 872	vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
 873					    file_inode(bprm->file));
 874	struct path_cond cond = {
 875		vfsuid_into_kuid(vfsuid),
 876		file_inode(bprm->file)->i_mode
 877	};
 878
 879	subj_cred = current_cred();
 880	ctx = task_ctx(current);
 881	AA_BUG(!cred_label(bprm->cred));
 882	AA_BUG(!ctx);
 883
 884	label = aa_get_newest_label(cred_label(bprm->cred));
 885
 886	/*
 887	 * Detect no new privs being set, and store the label it
 888	 * occurred under. Ideally this would happen when nnp
 889	 * is set but there isn't a good way to do that yet.
 890	 *
 891	 * Testing for unconfined must be done before the subset test
 892	 */
 893	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
 894	    !ctx->nnp)
 895		ctx->nnp = aa_get_label(label);
 896
 897	/* buffer freed below, name is pointer into buffer */
 898	buffer = aa_get_buffer(false);
 899	if (!buffer) {
 900		error = -ENOMEM;
 901		goto done;
 902	}
 903
 904	/* Test for onexec first as onexec override other x transitions. */
 905	if (ctx->onexec)
 906		new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
 907				    bprm, buffer, &cond, &unsafe);
 908	else
 909		new = fn_label_build(label, profile, GFP_KERNEL,
 910				profile_transition(subj_cred, profile, bprm,
 911						   buffer,
 912						   &cond, &unsafe));
 913
 914	AA_BUG(!new);
 915	if (IS_ERR(new)) {
 916		error = PTR_ERR(new);
 917		goto done;
 918	} else if (!new) {
 919		error = -ENOMEM;
 920		goto done;
 921	}
 922
 923	/* Policy has specified a domain transitions. If no_new_privs and
 924	 * confined ensure the transition is to confinement that is subset
 925	 * of the confinement when the task entered no new privs.
 926	 *
 927	 * NOTE: Domain transitions from unconfined and to stacked
 928	 * subsets are allowed even when no_new_privs is set because this
 929	 * aways results in a further reduction of permissions.
 930	 */
 931	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
 932	    !unconfined(label) &&
 933	    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
 934		error = -EPERM;
 935		info = "no new privs";
 936		goto audit;
 937	}
 938
 939	if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 940		/* FIXME: currently don't mediate shared state */
 941		;
 942	}
 943
 944	if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
 945		/* TODO: test needs to be profile of label to new */
 946		error = may_change_ptraced_domain(bprm->cred, new, &info);
 947		if (error)
 948			goto audit;
 949	}
 950
 951	if (unsafe) {
 952		if (DEBUG_ON) {
 953			dbg_printk("setting AT_SECURE for %s label=",
 954				   bprm->filename);
 955			aa_label_printk(new, GFP_KERNEL);
 956			dbg_printk("\n");
 957		}
 958		bprm->secureexec = 1;
 959	}
 960
 961	if (label->proxy != new->proxy) {
 962		/* when transitioning clear unsafe personality bits */
 963		if (DEBUG_ON) {
 964			dbg_printk("apparmor: clearing unsafe personality bits. %s label=",
 965				   bprm->filename);
 966			aa_label_printk(new, GFP_KERNEL);
 967			dbg_printk("\n");
 968		}
 969		bprm->per_clear |= PER_CLEAR_ON_SETID;
 970	}
 971	aa_put_label(cred_label(bprm->cred));
 972	/* transfer reference, released when cred is freed */
 973	set_cred_label(bprm->cred, new);
 974
 975done:
 976	aa_put_label(label);
 977	aa_put_buffer(buffer);
 978
 979	return error;
 980
 981audit:
 982	error = fn_for_each(label, profile,
 983			aa_audit_file(current_cred(), profile, &nullperms,
 984				      OP_EXEC, MAY_EXEC,
 985				      bprm->filename, NULL, new,
 986				      vfsuid_into_kuid(vfsuid), info, error));
 987	aa_put_label(new);
 988	goto done;
 989}
 990
 991/*
 992 * Functions for self directed profile change
 993 */
 994
 995
 996/* helper fn for change_hat
 997 *
 998 * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
 999 */
1000static struct aa_label *build_change_hat(const struct cred *subj_cred,
1001					 struct aa_profile *profile,
1002					 const char *name, bool sibling)
1003{
1004	struct aa_profile *root, *hat = NULL;
1005	const char *info = NULL;
1006	int error = 0;
1007
1008	if (sibling && PROFILE_IS_HAT(profile)) {
1009		root = aa_get_profile_rcu(&profile->parent);
1010	} else if (!sibling && !PROFILE_IS_HAT(profile)) {
1011		root = aa_get_profile(profile);
1012	} else {
1013		info = "conflicting target types";
1014		error = -EPERM;
1015		goto audit;
1016	}
1017
1018	hat = aa_find_child(root, name);
1019	if (!hat) {
1020		error = -ENOENT;
1021		if (COMPLAIN_MODE(profile)) {
1022			hat = aa_new_learning_profile(profile, true, name,
1023						      GFP_KERNEL);
1024			if (!hat) {
1025				info = "failed null profile create";
1026				error = -ENOMEM;
1027			}
1028		}
1029	}
1030	aa_put_profile(root);
1031
1032audit:
1033	aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1034		      AA_MAY_CHANGEHAT,
1035		      name, hat ? hat->base.hname : NULL,
1036		      hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1037		      error);
1038	if (!hat || (error && error != -ENOENT))
1039		return ERR_PTR(error);
1040	/* if hat && error - complain mode, already audited and we adjust for
1041	 * complain mode allow by returning hat->label
1042	 */
1043	return &hat->label;
1044}
1045
1046/* helper fn for changing into a hat
1047 *
1048 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1049 */
1050static struct aa_label *change_hat(const struct cred *subj_cred,
1051				   struct aa_label *label, const char *hats[],
1052				   int count, int flags)
1053{
1054	struct aa_profile *profile, *root, *hat = NULL;
1055	struct aa_label *new;
1056	struct label_it it;
1057	bool sibling = false;
1058	const char *name, *info = NULL;
1059	int i, error;
1060
1061	AA_BUG(!label);
1062	AA_BUG(!hats);
1063	AA_BUG(count < 1);
1064
1065	if (PROFILE_IS_HAT(labels_profile(label)))
1066		sibling = true;
1067
1068	/*find first matching hat */
1069	for (i = 0; i < count && !hat; i++) {
1070		name = hats[i];
1071		label_for_each_in_ns(it, labels_ns(label), label, profile) {
1072			if (sibling && PROFILE_IS_HAT(profile)) {
1073				root = aa_get_profile_rcu(&profile->parent);
1074			} else if (!sibling && !PROFILE_IS_HAT(profile)) {
1075				root = aa_get_profile(profile);
1076			} else {	/* conflicting change type */
1077				info = "conflicting targets types";
1078				error = -EPERM;
1079				goto fail;
1080			}
1081			hat = aa_find_child(root, name);
1082			aa_put_profile(root);
1083			if (!hat) {
1084				if (!COMPLAIN_MODE(profile))
1085					goto outer_continue;
1086				/* complain mode succeed as if hat */
1087			} else if (!PROFILE_IS_HAT(hat)) {
1088				info = "target not hat";
1089				error = -EPERM;
1090				aa_put_profile(hat);
1091				goto fail;
1092			}
1093			aa_put_profile(hat);
1094		}
1095		/* found a hat for all profiles in ns */
1096		goto build;
1097outer_continue:
1098	;
1099	}
1100	/* no hats that match, find appropriate error
1101	 *
1102	 * In complain mode audit of the failure is based off of the first
1103	 * hat supplied.  This is done due how userspace interacts with
1104	 * change_hat.
1105	 */
1106	name = NULL;
1107	label_for_each_in_ns(it, labels_ns(label), label, profile) {
1108		if (!list_empty(&profile->base.profiles)) {
1109			info = "hat not found";
1110			error = -ENOENT;
1111			goto fail;
1112		}
1113	}
1114	info = "no hats defined";
1115	error = -ECHILD;
1116
1117fail:
1118	label_for_each_in_ns(it, labels_ns(label), label, profile) {
1119		/*
1120		 * no target as it has failed to be found or built
1121		 *
1122		 * change_hat uses probing and should not log failures
1123		 * related to missing hats
1124		 */
1125		/* TODO: get rid of GLOBAL_ROOT_UID */
1126		if (count > 1 || COMPLAIN_MODE(profile)) {
1127			aa_audit_file(subj_cred, profile, &nullperms,
1128				      OP_CHANGE_HAT,
1129				      AA_MAY_CHANGEHAT, name, NULL, NULL,
1130				      GLOBAL_ROOT_UID, info, error);
1131		}
1132	}
1133	return ERR_PTR(error);
1134
1135build:
1136	new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1137				   build_change_hat(subj_cred, profile, name,
1138						    sibling),
1139				   aa_get_label(&profile->label));
1140	if (!new) {
1141		info = "label build failed";
1142		error = -ENOMEM;
1143		goto fail;
1144	} /* else if (IS_ERR) build_change_hat has logged error so return new */
1145
1146	return new;
1147}
1148
1149/**
1150 * aa_change_hat - change hat to/from subprofile
1151 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1152 * @count: number of hat names in @hats
1153 * @token: magic value to validate the hat change
1154 * @flags: flags affecting behavior of the change
1155 *
1156 * Returns %0 on success, error otherwise.
1157 *
1158 * Change to the first profile specified in @hats that exists, and store
1159 * the @hat_magic in the current task context.  If the count == 0 and the
1160 * @token matches that stored in the current task context, return to the
1161 * top level profile.
1162 *
1163 * change_hat only applies to profiles in the current ns, and each profile
1164 * in the ns must make the same transition otherwise change_hat will fail.
1165 */
1166int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1167{
1168	const struct cred *subj_cred;
1169	struct aa_task_ctx *ctx = task_ctx(current);
1170	struct aa_label *label, *previous, *new = NULL, *target = NULL;
1171	struct aa_profile *profile;
1172	struct aa_perms perms = {};
1173	const char *info = NULL;
1174	int error = 0;
1175
1176	/* released below */
1177	subj_cred = get_current_cred();
1178	label = aa_get_newest_cred_label(subj_cred);
1179	previous = aa_get_newest_label(ctx->previous);
1180
1181	/*
1182	 * Detect no new privs being set, and store the label it
1183	 * occurred under. Ideally this would happen when nnp
1184	 * is set but there isn't a good way to do that yet.
1185	 *
1186	 * Testing for unconfined must be done before the subset test
1187	 */
1188	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1189		ctx->nnp = aa_get_label(label);
1190
1191	if (unconfined(label)) {
1192		info = "unconfined can not change_hat";
1193		error = -EPERM;
1194		goto fail;
1195	}
1196
1197	if (count) {
1198		new = change_hat(subj_cred, label, hats, count, flags);
1199		AA_BUG(!new);
1200		if (IS_ERR(new)) {
1201			error = PTR_ERR(new);
1202			new = NULL;
1203			/* already audited */
1204			goto out;
1205		}
1206
1207		/* target cred is the same as current except new label */
1208		error = may_change_ptraced_domain(subj_cred, new, &info);
1209		if (error)
1210			goto fail;
1211
1212		/*
1213		 * no new privs prevents domain transitions that would
1214		 * reduce restrictions.
1215		 */
1216		if (task_no_new_privs(current) && !unconfined(label) &&
1217		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1218			/* not an apparmor denial per se, so don't log it */
1219			AA_DEBUG("no_new_privs - change_hat denied");
1220			error = -EPERM;
1221			goto out;
1222		}
1223
1224		if (flags & AA_CHANGE_TEST)
1225			goto out;
1226
1227		target = new;
1228		error = aa_set_current_hat(new, token);
1229		if (error == -EACCES)
1230			/* kill task in case of brute force attacks */
1231			goto kill;
1232	} else if (previous && !(flags & AA_CHANGE_TEST)) {
1233		/*
1234		 * no new privs prevents domain transitions that would
1235		 * reduce restrictions.
1236		 */
1237		if (task_no_new_privs(current) && !unconfined(label) &&
1238		    !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1239			/* not an apparmor denial per se, so don't log it */
1240			AA_DEBUG("no_new_privs - change_hat denied");
1241			error = -EPERM;
1242			goto out;
1243		}
1244
1245		/* Return to saved label.  Kill task if restore fails
1246		 * to avoid brute force attacks
1247		 */
1248		target = previous;
1249		error = aa_restore_previous_label(token);
1250		if (error) {
1251			if (error == -EACCES)
1252				goto kill;
1253			goto fail;
1254		}
1255	} /* else ignore @flags && restores when there is no saved profile */
1256
1257out:
1258	aa_put_label(new);
1259	aa_put_label(previous);
1260	aa_put_label(label);
1261	put_cred(subj_cred);
1262
1263	return error;
1264
1265kill:
1266	info = "failed token match";
1267	perms.kill = AA_MAY_CHANGEHAT;
1268
1269fail:
1270	fn_for_each_in_ns(label, profile,
1271		aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1272			      AA_MAY_CHANGEHAT, NULL, NULL, target,
1273			      GLOBAL_ROOT_UID, info, error));
1274
1275	goto out;
1276}
1277
1278
1279static int change_profile_perms_wrapper(const char *op, const char *name,
1280					const struct cred *subj_cred,
1281					struct aa_profile *profile,
1282					struct aa_label *target, bool stack,
1283					u32 request, struct aa_perms *perms)
1284{
1285	struct aa_ruleset *rules = list_first_entry(&profile->rules,
1286						    typeof(*rules), list);
1287	const char *info = NULL;
1288	int error = 0;
1289
1290	if (!error)
1291		error = change_profile_perms(profile, target, stack, request,
1292					     rules->file->start[AA_CLASS_FILE],
1293					     perms);
1294	if (error)
1295		error = aa_audit_file(subj_cred, profile, perms, op, request,
1296				      name,
1297				      NULL, target, GLOBAL_ROOT_UID, info,
1298				      error);
1299
1300	return error;
1301}
1302
1303static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
1304
1305/**
1306 * aa_change_profile - perform a one-way profile transition
1307 * @fqname: name of profile may include namespace (NOT NULL)
1308 * @flags: flags affecting change behavior
1309 *
1310 * Change to new profile @name.  Unlike with hats, there is no way
1311 * to change back.  If @name isn't specified the current profile name is
1312 * used.
1313 * If @onexec then the transition is delayed until
1314 * the next exec.
1315 *
1316 * Returns %0 on success, error otherwise.
1317 */
1318int aa_change_profile(const char *fqname, int flags)
1319{
1320	struct aa_label *label, *new = NULL, *target = NULL;
1321	struct aa_profile *profile;
1322	struct aa_perms perms = {};
1323	const char *info = NULL;
1324	const char *auditname = fqname;		/* retain leading & if stack */
1325	bool stack = flags & AA_CHANGE_STACK;
1326	struct aa_task_ctx *ctx = task_ctx(current);
1327	const struct cred *subj_cred = get_current_cred();
1328	int error = 0;
1329	char *op;
1330	u32 request;
1331
1332	label = aa_get_current_label();
1333
1334	/*
1335	 * Detect no new privs being set, and store the label it
1336	 * occurred under. Ideally this would happen when nnp
1337	 * is set but there isn't a good way to do that yet.
1338	 *
1339	 * Testing for unconfined must be done before the subset test
1340	 */
1341	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1342		ctx->nnp = aa_get_label(label);
1343
1344	if (!fqname || !*fqname) {
1345		aa_put_label(label);
1346		AA_DEBUG("no profile name");
1347		return -EINVAL;
1348	}
1349
1350	if (flags & AA_CHANGE_ONEXEC) {
1351		request = AA_MAY_ONEXEC;
1352		if (stack)
1353			op = OP_STACK_ONEXEC;
1354		else
1355			op = OP_CHANGE_ONEXEC;
1356	} else {
1357		request = AA_MAY_CHANGE_PROFILE;
1358		if (stack)
1359			op = OP_STACK;
1360		else
1361			op = OP_CHANGE_PROFILE;
1362	}
1363
1364	/* This should move to a per profile test. Requires pushing build
1365	 * into callback
1366	 */
1367	if (!stack && unconfined(label) &&
1368	    label == &labels_ns(label)->unconfined->label &&
1369	    aa_unprivileged_unconfined_restricted &&
1370	    /* TODO: refactor so this check is a fn */
1371	    cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
1372			CAP_OPT_NOAUDIT)) {
1373		/* regardless of the request in this case apparmor
1374		 * stacks against unconfined so admin set policy can't be
1375		 * by-passed
1376		 */
1377		stack = true;
1378		perms.audit = request;
1379		(void) fn_for_each_in_ns(label, profile,
1380				aa_audit_file(subj_cred, profile, &perms, op,
1381					      request, auditname, NULL, target,
1382					      GLOBAL_ROOT_UID, stack_msg, 0));
1383		perms.audit = 0;
1384	}
1385
1386	if (*fqname == '&') {
1387		stack = true;
1388		/* don't have label_parse() do stacking */
1389		fqname++;
1390	}
1391	target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1392	if (IS_ERR(target)) {
1393		struct aa_profile *tprofile;
1394
1395		info = "label not found";
1396		error = PTR_ERR(target);
1397		target = NULL;
1398		/*
1399		 * TODO: fixme using labels_profile is not right - do profile
1400		 * per complain profile
1401		 */
1402		if ((flags & AA_CHANGE_TEST) ||
1403		    !COMPLAIN_MODE(labels_profile(label)))
1404			goto audit;
1405		/* released below */
1406		tprofile = aa_new_learning_profile(labels_profile(label), false,
1407						   fqname, GFP_KERNEL);
1408		if (!tprofile) {
1409			info = "failed null profile create";
1410			error = -ENOMEM;
1411			goto audit;
1412		}
1413		target = &tprofile->label;
1414		goto check;
1415	}
1416
1417	/*
1418	 * self directed transitions only apply to current policy ns
1419	 * TODO: currently requiring perms for stacking and straight change
1420	 *       stacking doesn't strictly need this. Determine how much
1421	 *       we want to loosen this restriction for stacking
1422	 *
1423	 * if (!stack) {
1424	 */
1425	error = fn_for_each_in_ns(label, profile,
1426			change_profile_perms_wrapper(op, auditname,
1427						     subj_cred,
1428						     profile, target, stack,
1429						     request, &perms));
1430	if (error)
1431		/* auditing done in change_profile_perms_wrapper */
1432		goto out;
1433
1434	/* } */
1435
1436check:
1437	/* check if tracing task is allowed to trace target domain */
1438	error = may_change_ptraced_domain(subj_cred, target, &info);
1439	if (error && !fn_for_each_in_ns(label, profile,
1440					COMPLAIN_MODE(profile)))
1441		goto audit;
1442
1443	/* TODO: add permission check to allow this
1444	 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1445	 *      info = "not a single threaded task";
1446	 *      error = -EACCES;
1447	 *      goto audit;
1448	 * }
1449	 */
1450	if (flags & AA_CHANGE_TEST)
1451		goto out;
1452
1453	/* stacking is always a subset, so only check the nonstack case */
1454	if (!stack) {
1455		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1456					   aa_get_label(target),
1457					   aa_get_label(&profile->label));
1458		/*
1459		 * no new privs prevents domain transitions that would
1460		 * reduce restrictions.
1461		 */
1462		if (task_no_new_privs(current) && !unconfined(label) &&
1463		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1464			/* not an apparmor denial per se, so don't log it */
1465			AA_DEBUG("no_new_privs - change_hat denied");
1466			error = -EPERM;
1467			goto out;
1468		}
1469	}
1470
1471	if (!(flags & AA_CHANGE_ONEXEC)) {
1472		/* only transition profiles in the current ns */
1473		if (stack)
1474			new = aa_label_merge(label, target, GFP_KERNEL);
1475		if (IS_ERR_OR_NULL(new)) {
1476			info = "failed to build target label";
1477			if (!new)
1478				error = -ENOMEM;
1479			else
1480				error = PTR_ERR(new);
1481			new = NULL;
1482			perms.allow = 0;
1483			goto audit;
1484		}
1485		error = aa_replace_current_label(new);
1486	} else {
1487		if (new) {
1488			aa_put_label(new);
1489			new = NULL;
1490		}
1491
1492		/* full transition will be built in exec path */
1493		aa_set_current_onexec(target, stack);
1494	}
1495
1496audit:
1497	error = fn_for_each_in_ns(label, profile,
1498			aa_audit_file(subj_cred,
1499				      profile, &perms, op, request, auditname,
1500				      NULL, new ? new : target,
1501				      GLOBAL_ROOT_UID, info, error));
1502
1503out:
1504	aa_put_label(new);
1505	aa_put_label(target);
1506	aa_put_label(label);
1507	put_cred(subj_cred);
1508
1509	return error;
1510}