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v4.6
 
  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 * @to_profile: profile to change to  (NOT NULL)
 
 54 *
 55 * Check if current is ptraced and if so if the tracing task is allowed
 56 * to trace the new domain
 57 *
 58 * Returns: %0 or error if change not allowed
 59 */
 60static int may_change_ptraced_domain(struct aa_profile *to_profile)
 
 61{
 62	struct task_struct *tracer;
 63	struct aa_profile *tracerp = NULL;
 64	int error = 0;
 65
 66	rcu_read_lock();
 67	tracer = ptrace_parent(current);
 68	if (tracer)
 69		/* released below */
 70		tracerp = aa_get_task_profile(tracer);
 71
 72	/* not ptraced */
 73	if (!tracer || unconfined(tracerp))
 74		goto out;
 75
 76	error = aa_may_ptrace(tracerp, to_profile, PTRACE_MODE_ATTACH);
 77
 78out:
 79	rcu_read_unlock();
 80	aa_put_profile(tracerp);
 81
 
 
 82	return error;
 83}
 84
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 85/**
 86 * change_profile_perms - find permissions for change_profile
 87 * @profile: the current profile  (NOT NULL)
 88 * @ns: the namespace being switched to  (NOT NULL)
 89 * @name: the name of the profile to change to  (NOT NULL)
 90 * @request: requested perms
 91 * @start: state to start matching in
 92 *
 
 93 * Returns: permission set
 
 
 
 94 */
 95static struct file_perms change_profile_perms(struct aa_profile *profile,
 96					      struct aa_namespace *ns,
 97					      const char *name, u32 request,
 98					      unsigned int start)
 99{
100	struct file_perms perms;
101	struct path_cond cond = { };
102	unsigned int state;
103
104	if (unconfined(profile)) {
105		perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
106		perms.audit = perms.quiet = perms.kill = 0;
107		return perms;
108	} else if (!profile->file.dfa) {
109		return nullperms;
110	} else if ((ns == profile->ns)) {
111		/* try matching against rules with out namespace prepended */
112		aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
113		if (COMBINED_PERM_MASK(perms) & request)
114			return perms;
115	}
116
117	/* try matching with namespace name and then profile */
118	state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
119	state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
120	aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
121
122	return perms;
 
 
123}
124
125/**
126 * __attach_match_ - find an attachment match
127 * @name - to match against  (NOT NULL)
 
128 * @head - profile list to walk  (NOT NULL)
 
 
129 *
130 * Do a linear search on the profiles in the list.  There is a matching
131 * preference where an exact match is preferred over a name which uses
132 * expressions to match, and matching expressions with the greatest
133 * xmatch_len are preferred.
134 *
135 * Requires: @head not be shared or have appropriate locks held
136 *
137 * Returns: profile or NULL if no match found
138 */
139static struct aa_profile *__attach_match(const char *name,
140					 struct list_head *head)
 
141{
142	int len = 0;
 
143	struct aa_profile *profile, *candidate = NULL;
144
 
 
 
 
 
145	list_for_each_entry_rcu(profile, head, base.list) {
146		if (profile->flags & PFLAG_NULL)
 
 
 
147			continue;
148		if (profile->xmatch && profile->xmatch_len > len) {
149			unsigned int state = aa_dfa_match(profile->xmatch,
150							  DFA_START, name);
151			u32 perm = dfa_user_allow(profile->xmatch, state);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
152			/* any accepting state means a valid match. */
153			if (perm & MAY_EXEC) {
154				candidate = profile;
155				len = profile->xmatch_len;
156			}
157		} else if (!strcmp(profile->base.name, name))
158			/* exact non-re match, no more searching required */
159			return profile;
160	}
161
162	return candidate;
163}
164
165/**
166 * find_attach - do attachment search for unconfined processes
167 * @ns: the current namespace  (NOT NULL)
168 * @list: list to search  (NOT NULL)
169 * @name: the executable name to match against  (NOT NULL)
170 *
171 * Returns: profile or NULL if no match found
172 */
173static struct aa_profile *find_attach(struct aa_namespace *ns,
174				      struct list_head *list, const char *name)
175{
176	struct aa_profile *profile;
177
178	rcu_read_lock();
179	profile = aa_get_profile(__attach_match(name, list));
180	rcu_read_unlock();
181
182	return profile;
183}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
184
185/**
186 * separate_fqname - separate the namespace and profile names
187 * @fqname: the fqname name to split  (NOT NULL)
188 * @ns_name: the namespace name if it exists  (NOT NULL)
189 *
190 * This is the xtable equivalent routine of aa_split_fqname.  It finds the
191 * split in an xtable fqname which contains an embedded \0 instead of a :
192 * if a namespace is specified.  This is done so the xtable is constant and
193 * isn't re-split on every lookup.
194 *
195 * Either the profile or namespace name may be optional but if the namespace
196 * is specified the profile name termination must be present.  This results
197 * in the following possible encodings:
198 * profile_name\0
199 * :ns_name\0profile_name\0
200 * :ns_name\0\0
201 *
202 * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
203 *
204 * Returns: profile name if it is specified else NULL
205 */
206static const char *separate_fqname(const char *fqname, const char **ns_name)
207{
208	const char *name;
209
210	if (fqname[0] == ':') {
211		/* In this case there is guaranteed to be two \0 terminators
212		 * in the string.  They are verified at load time by
213		 * by unpack_trans_table
214		 */
215		*ns_name = fqname + 1;		/* skip : */
216		name = *ns_name + strlen(*ns_name) + 1;
217		if (!*name)
218			name = NULL;
219	} else {
220		*ns_name = NULL;
221		name = fqname;
222	}
223
224	return name;
 
 
 
 
225}
226
227static const char *next_name(int xtype, const char *name)
228{
229	return NULL;
230}
231
232/**
233 * x_table_lookup - lookup an x transition name via transition table
234 * @profile: current profile (NOT NULL)
235 * @xindex: index into x transition table
 
236 *
237 * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
238 */
239static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
 
240{
241	struct aa_profile *new_profile = NULL;
242	struct aa_namespace *ns = profile->ns;
 
243	u32 xtype = xindex & AA_X_TYPE_MASK;
244	int index = xindex & AA_X_INDEX_MASK;
245	const char *name;
246
247	/* index is guaranteed to be in range, validated at load time */
248	for (name = profile->file.trans.table[index]; !new_profile && name;
249	     name = next_name(xtype, name)) {
250		struct aa_namespace *new_ns;
251		const char *xname = NULL;
252
253		new_ns = NULL;
 
 
 
 
 
254		if (xindex & AA_X_CHILD) {
 
255			/* release by caller */
256			new_profile = aa_find_child(profile, name);
257			continue;
258		} else if (*name == ':') {
259			/* switching namespace */
260			const char *ns_name;
261			xname = name = separate_fqname(name, &ns_name);
262			if (!xname)
263				/* no name so use profile name */
264				xname = profile->base.hname;
265			if (*ns_name == '@') {
266				/* TODO: variable support */
267				;
268			}
269			/* released below */
270			new_ns = aa_find_namespace(ns, ns_name);
271			if (!new_ns)
272				continue;
273		} else if (*name == '@') {
274			/* TODO: variable support */
275			continue;
276		} else {
277			/* basic namespace lookup */
278			xname = name;
279		}
280
281		/* released by caller */
282		new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
283		aa_put_namespace(new_ns);
284	}
285
286	/* released by caller */
287	return new_profile;
 
288}
289
290/**
291 * x_to_profile - get target profile for a given xindex
292 * @profile: current profile  (NOT NULL)
 
293 * @name: name to lookup (NOT NULL)
294 * @xindex: index into x transition table
 
295 *
296 * find profile for a transition index
297 *
298 * Returns: refcounted profile or NULL if not found available
299 */
300static struct aa_profile *x_to_profile(struct aa_profile *profile,
301				       const char *name, u32 xindex)
 
 
 
302{
303	struct aa_profile *new_profile = NULL;
304	struct aa_namespace *ns = profile->ns;
 
 
305	u32 xtype = xindex & AA_X_TYPE_MASK;
 
306
307	switch (xtype) {
308	case AA_X_NONE:
309		/* fail exec unless ix || ux fallback - handled by caller */
310		return NULL;
 
 
 
 
 
 
 
 
 
 
 
311	case AA_X_NAME:
312		if (xindex & AA_X_CHILD)
313			/* released by caller */
314			new_profile = find_attach(ns, &profile->base.profiles,
315						  name);
316		else
317			/* released by caller */
318			new_profile = find_attach(ns, &ns->base.profiles,
319						  name);
320		break;
321	case AA_X_TABLE:
322		/* released by caller */
323		new_profile = x_table_lookup(profile, xindex);
324		break;
325	}
326
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
327	/* released by caller */
328	return new_profile;
329}
330
331/**
332 * apparmor_bprm_set_creds - set the new creds on the bprm struct
333 * @bprm: binprm for the exec  (NOT NULL)
334 *
335 * Returns: %0 or error on failure
336 */
337int apparmor_bprm_set_creds(struct linux_binprm *bprm)
338{
339	struct aa_task_cxt *cxt;
340	struct aa_profile *profile, *new_profile = NULL;
341	struct aa_namespace *ns;
342	char *buffer = NULL;
343	unsigned int state;
344	struct file_perms perms = {};
345	struct path_cond cond = {
346		file_inode(bprm->file)->i_uid,
347		file_inode(bprm->file)->i_mode
348	};
349	const char *name = NULL, *target = NULL, *info = NULL;
350	int error = 0;
351
352	if (bprm->cred_prepared)
353		return 0;
354
355	cxt = cred_cxt(bprm->cred);
356	BUG_ON(!cxt);
357
358	profile = aa_get_newest_profile(cxt->profile);
359	/*
360	 * get the namespace from the replacement profile as replacement
361	 * can change the namespace
362	 */
363	ns = profile->ns;
364	state = profile->file.start;
365
366	/* buffer freed below, name is pointer into buffer */
367	error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
368			     &name, &info);
369	if (error) {
370		if (unconfined(profile) ||
371		    (profile->flags & PFLAG_IX_ON_NAME_ERROR))
 
372			error = 0;
 
 
373		name = bprm->filename;
374		goto audit;
375	}
376
377	/* Test for onexec first as onexec directives override other
378	 * x transitions.
379	 */
380	if (unconfined(profile)) {
381		/* unconfined task */
382		if (cxt->onexec)
383			/* change_profile on exec already been granted */
384			new_profile = aa_get_profile(cxt->onexec);
385		else
386			new_profile = find_attach(ns, &ns->base.profiles, name);
387		if (!new_profile)
388			goto cleanup;
389		/*
390		 * NOTE: Domain transitions from unconfined are allowed
391		 * even when no_new_privs is set because this aways results
392		 * in a further reduction of permissions.
393		 */
394		goto apply;
395	}
396
397	/* find exec permissions for name */
398	state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
399	if (cxt->onexec) {
400		struct file_perms cp;
401		info = "change_profile onexec";
402		if (!(perms.allow & AA_MAY_ONEXEC))
403			goto audit;
404
405		/* test if this exec can be paired with change_profile onexec.
406		 * onexec permission is linked to exec with a standard pairing
407		 * exec\0change_profile
408		 */
409		state = aa_dfa_null_transition(profile->file.dfa, state);
410		cp = change_profile_perms(profile, cxt->onexec->ns,
411					  cxt->onexec->base.name,
412					  AA_MAY_ONEXEC, state);
413
414		if (!(cp.allow & AA_MAY_ONEXEC))
415			goto audit;
416		new_profile = aa_get_newest_profile(cxt->onexec);
417		goto apply;
418	}
419
420	if (perms.allow & MAY_EXEC) {
421		/* exec permission determine how to transition */
422		new_profile = x_to_profile(profile, name, perms.xindex);
423		if (!new_profile) {
424			if (perms.xindex & AA_X_INHERIT) {
425				/* (p|c|n)ix - don't change profile but do
426				 * use the newest version, which was picked
427				 * up above when getting profile
428				 */
429				info = "ix fallback";
430				new_profile = aa_get_profile(profile);
431				goto x_clear;
432			} else if (perms.xindex & AA_X_UNCONFINED) {
433				new_profile = aa_get_newest_profile(ns->unconfined);
434				info = "ux fallback";
435			} else {
436				error = -ENOENT;
437				info = "profile not found";
438				/* remove MAY_EXEC to audit as failure */
439				perms.allow &= ~MAY_EXEC;
440			}
441		}
442	} else if (COMPLAIN_MODE(profile)) {
443		/* no exec permission - are we in learning mode */
444		new_profile = aa_new_null_profile(profile, 0);
 
 
 
445		if (!new_profile) {
446			error = -ENOMEM;
447			info = "could not create null profile";
448		} else {
449			error = -EACCES;
450			target = new_profile->base.hname;
451		}
452		perms.xindex |= AA_X_UNSAFE;
453	} else
454		/* fail exec */
455		error = -EACCES;
456
457	/*
458	 * Policy has specified a domain transition, if no_new_privs then
459	 * fail the exec.
460	 */
461	if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
462		aa_put_profile(new_profile);
463		error = -EPERM;
464		goto cleanup;
 
 
 
 
465	}
466
467	if (!new_profile)
468		goto audit;
 
 
 
 
 
469
470	if (bprm->unsafe & LSM_UNSAFE_SHARE) {
471		/* FIXME: currently don't mediate shared state */
472		;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
473	}
474
475	if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
476		error = may_change_ptraced_domain(new_profile);
477		if (error) {
478			aa_put_profile(new_profile);
479			goto audit;
 
 
480		}
 
 
481	}
482
483	/* Determine if secure exec is needed.
484	 * Can be at this point for the following reasons:
485	 * 1. unconfined switching to confined
486	 * 2. confined switching to different confinement
487	 * 3. confined switching to unconfined
488	 *
489	 * Cases 2 and 3 are marked as requiring secure exec
490	 * (unless policy specified "unsafe exec")
491	 *
492	 * bprm->unsafe is used to cache the AA_X_UNSAFE permission
493	 * to avoid having to recompute in secureexec
494	 */
495	if (!(perms.xindex & AA_X_UNSAFE)) {
496		AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
497			 name, new_profile->base.hname);
498		bprm->unsafe |= AA_SECURE_X_NEEDED;
499	}
500apply:
501	target = new_profile->base.hname;
502	/* when transitioning profiles clear unsafe personality bits */
503	bprm->per_clear |= PER_CLEAR_ON_SETID;
504
505x_clear:
506	aa_put_profile(cxt->profile);
507	/* transfer new profile reference will be released when cxt is freed */
508	cxt->profile = new_profile;
509
510	/* clear out all temporary/transitional state from the context */
511	aa_clear_task_cxt_trans(cxt);
 
 
 
 
 
 
 
512
513audit:
514	error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
515			      name, target, cond.uid, info, error);
 
516
517cleanup:
518	aa_put_profile(profile);
519	kfree(buffer);
520
521	return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
522}
523
524/**
525 * apparmor_bprm_secureexec - determine if secureexec is needed
526 * @bprm: binprm for exec  (NOT NULL)
527 *
528 * Returns: %1 if secureexec is needed else %0
 
 
529 */
530int apparmor_bprm_secureexec(struct linux_binprm *bprm)
531{
532	/* the decision to use secure exec is computed in set_creds
533	 * and stored in bprm->unsafe.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
534	 */
535	if (bprm->unsafe & AA_SECURE_X_NEEDED)
536		return 1;
 
537
538	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
539}
540
541/**
542 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
543 * @bprm: binprm for the exec  (NOT NULL)
544 */
545void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
 
 
 
 
 
 
 
546{
547	struct aa_profile *profile = __aa_current_profile();
548	struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred);
 
549
550	/* bail out if unconfined or not changing profile */
551	if ((new_cxt->profile == profile) ||
552	    (unconfined(new_cxt->profile)))
553		return;
 
 
 
 
 
554
555	current->pdeath_signal = 0;
 
 
 
 
 
 
 
 
 
 
 
 
556
557	/* reset soft limits and set hard limits for the new profile */
558	__aa_transition_rlimits(profile, new_cxt->profile);
 
 
 
 
 
 
 
 
 
559}
560
561/**
562 * apparmor_bprm_commited_cred - do cleanup after new creds committed
563 * @bprm: binprm for the exec  (NOT NULL)
564 */
565void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 
566{
567	/* TODO: cleanup signals - ipc mediation */
568	return;
569}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
570
571/*
572 * Functions for self directed profile change
573 */
 
 
 
 
 
 
 
 
 
 
 
 
 
574
575/**
576 * new_compound_name - create an hname with @n2 appended to @n1
577 * @n1: base of hname  (NOT NULL)
578 * @n2: name to append (NOT NULL)
579 *
580 * Returns: new name or NULL on error
581 */
582static char *new_compound_name(const char *n1, const char *n2)
583{
584	char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
585	if (name)
586		sprintf(name, "%s//%s", n1, n2);
587	return name;
588}
589
590/**
591 * aa_change_hat - change hat to/from subprofile
592 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
593 * @count: number of hat names in @hats
594 * @token: magic value to validate the hat change
595 * @permtest: true if this is just a permission test
 
 
596 *
597 * Change to the first profile specified in @hats that exists, and store
598 * the @hat_magic in the current task context.  If the count == 0 and the
599 * @token matches that stored in the current task context, return to the
600 * top level profile.
601 *
602 * Returns %0 on success, error otherwise.
 
603 */
604int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
605{
606	const struct cred *cred;
607	struct aa_task_cxt *cxt;
608	struct aa_profile *profile, *previous_profile, *hat = NULL;
609	char *name = NULL;
610	int i;
611	struct file_perms perms = {};
612	const char *target = NULL, *info = NULL;
613	int error = 0;
614
615	/*
616	 * Fail explicitly requested domain transitions if no_new_privs.
617	 * There is no exception for unconfined as change_hat is not
618	 * available.
619	 */
620	if (task_no_new_privs(current))
621		return -EPERM;
622
623	/* released below */
624	cred = get_current_cred();
625	cxt = cred_cxt(cred);
626	profile = aa_cred_profile(cred);
627	previous_profile = cxt->previous;
 
 
 
 
 
 
 
 
 
628
629	if (unconfined(profile)) {
630		info = "unconfined";
631		error = -EPERM;
632		goto audit;
633	}
634
635	if (count) {
636		/* attempting to change into a new hat or switch to a sibling */
637		struct aa_profile *root;
638		if (PROFILE_IS_HAT(profile))
639			root = aa_get_profile_rcu(&profile->parent);
640		else
641			root = aa_get_profile(profile);
642
643		/* find first matching hat */
644		for (i = 0; i < count && !hat; i++)
645			/* released below */
646			hat = aa_find_child(root, hats[i]);
647		if (!hat) {
648			if (!COMPLAIN_MODE(root) || permtest) {
649				if (list_empty(&root->base.profiles))
650					error = -ECHILD;
651				else
652					error = -ENOENT;
653				aa_put_profile(root);
654				goto out;
655			}
656
657			/*
658			 * In complain mode and failed to match any hats.
659			 * Audit the failure is based off of the first hat
660			 * supplied.  This is done due how userspace
661			 * interacts with change_hat.
662			 *
663			 * TODO: Add logging of all failed hats
664			 */
665
666			/* freed below */
667			name = new_compound_name(root->base.hname, hats[0]);
668			aa_put_profile(root);
669			target = name;
670			/* released below */
671			hat = aa_new_null_profile(profile, 1);
672			if (!hat) {
673				info = "failed null profile create";
674				error = -ENOMEM;
675				goto audit;
676			}
677		} else {
678			aa_put_profile(root);
679			target = hat->base.hname;
680			if (!PROFILE_IS_HAT(hat)) {
681				info = "target not hat";
682				error = -EPERM;
683				goto audit;
684			}
685		}
686
687		error = may_change_ptraced_domain(hat);
688		if (error) {
689			info = "ptraced";
 
 
 
 
 
 
 
 
 
 
 
 
 
 
690			error = -EPERM;
691			goto audit;
692		}
693
694		if (!permtest) {
695			error = aa_set_current_hat(hat, token);
696			if (error == -EACCES)
697				/* kill task in case of brute force attacks */
698				perms.kill = AA_MAY_CHANGEHAT;
699			else if (name && !error)
700				/* reset error for learning of new hats */
701				error = -ENOENT;
702		}
703	} else if (previous_profile) {
704		/* Return to saved profile.  Kill task if restore fails
705		 * to avoid brute force attacks
706		 */
707		target = previous_profile->base.hname;
708		error = aa_restore_previous_profile(token);
709		perms.kill = AA_MAY_CHANGEHAT;
710	} else
711		/* ignore restores when there is no saved profile */
712		goto out;
713
714audit:
715	if (!permtest)
716		error = aa_audit_file(profile, &perms, GFP_KERNEL,
717				      OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
718				      target, GLOBAL_ROOT_UID, info, error);
719
720out:
721	aa_put_profile(hat);
722	kfree(name);
 
723	put_cred(cred);
724
725	return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
726}
727
728/**
729 * aa_change_profile - perform a one-way profile transition
730 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
731 * @hname: name of profile to change to (MAYBE NULL)
732 * @onexec: whether this transition is to take place immediately or at exec
733 * @permtest: true if this is just a permission test
734 *
735 * Change to new profile @name.  Unlike with hats, there is no way
736 * to change back.  If @name isn't specified the current profile name is
737 * used.
738 * If @onexec then the transition is delayed until
739 * the next exec.
740 *
741 * Returns %0 on success, error otherwise.
742 */
743int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
744		      bool permtest)
745{
746	const struct cred *cred;
747	struct aa_profile *profile, *target = NULL;
748	struct aa_namespace *ns = NULL;
749	struct file_perms perms = {};
750	const char *name = NULL, *info = NULL;
751	int op, error = 0;
 
 
 
752	u32 request;
753
754	if (!hname && !ns_name)
755		return -EINVAL;
756
757	if (onexec) {
758		request = AA_MAY_ONEXEC;
759		op = OP_CHANGE_ONEXEC;
760	} else {
761		request = AA_MAY_CHANGE_PROFILE;
762		op = OP_CHANGE_PROFILE;
763	}
764
765	cred = get_current_cred();
766	profile = aa_cred_profile(cred);
767
768	/*
769	 * Fail explicitly requested domain transitions if no_new_privs
770	 * and not unconfined.
771	 * Domain transitions from unconfined are allowed even when
772	 * no_new_privs is set because this aways results in a reduction
773	 * of permissions.
774	 */
775	if (task_no_new_privs(current) && !unconfined(profile)) {
776		put_cred(cred);
777		return -EPERM;
778	}
779
780	if (ns_name) {
781		/* released below */
782		ns = aa_find_namespace(profile->ns, ns_name);
783		if (!ns) {
784			/* we don't create new namespace in complain mode */
785			name = ns_name;
786			info = "namespace not found";
787			error = -ENOENT;
788			goto audit;
789		}
790	} else
791		/* released below */
792		ns = aa_get_namespace(profile->ns);
793
794	/* if the name was not specified, use the name of the current profile */
795	if (!hname) {
796		if (unconfined(profile))
797			hname = ns->unconfined->base.hname;
 
 
 
 
 
 
798		else
799			hname = profile->base.hname;
800	}
801
802	perms = change_profile_perms(profile, ns, hname, request,
803				     profile->file.start);
804	if (!(perms.allow & request)) {
805		error = -EACCES;
806		goto audit;
807	}
808
809	/* released below */
810	target = aa_lookup_profile(ns, hname);
811	if (!target) {
812		info = "profile not found";
813		error = -ENOENT;
814		if (permtest || !COMPLAIN_MODE(profile))
 
 
 
 
 
 
815			goto audit;
816		/* released below */
817		target = aa_new_null_profile(profile, 0);
818		if (!target) {
 
819			info = "failed null profile create";
820			error = -ENOMEM;
821			goto audit;
822		}
 
 
823	}
824
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
825	/* check if tracing task is allowed to trace target domain */
826	error = may_change_ptraced_domain(target);
827	if (error) {
828		info = "ptrace prevents transition";
829		goto audit;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
830	}
831
832	if (permtest)
833		goto audit;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
834
835	if (onexec)
836		error = aa_set_current_onexec(target);
837	else
838		error = aa_replace_current_profile(target);
839
840audit:
841	if (!permtest)
842		error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
843				      name, hname, GLOBAL_ROOT_UID, info, error);
 
844
845	aa_put_namespace(ns);
846	aa_put_profile(target);
847	put_cred(cred);
 
848
849	return error;
850}
v6.2
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * AppArmor security module
   4 *
   5 * This file contains AppArmor policy attachment and domain transitions
   6 *
   7 * Copyright (C) 2002-2008 Novell/SUSE
   8 * Copyright 2009-2010 Canonical Ltd.
 
 
 
 
 
   9 */
  10
  11#include <linux/errno.h>
  12#include <linux/fdtable.h>
  13#include <linux/fs.h>
  14#include <linux/file.h>
  15#include <linux/mount.h>
  16#include <linux/syscalls.h>
 
  17#include <linux/personality.h>
  18#include <linux/xattr.h>
  19#include <linux/user_namespace.h>
  20
  21#include "include/audit.h"
  22#include "include/apparmorfs.h"
  23#include "include/cred.h"
  24#include "include/domain.h"
  25#include "include/file.h"
  26#include "include/ipc.h"
  27#include "include/match.h"
  28#include "include/path.h"
  29#include "include/policy.h"
  30#include "include/policy_ns.h"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  31
  32/**
  33 * may_change_ptraced_domain - check if can change profile on ptraced task
  34 * @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(struct aa_label *to_label,
  43				     const char **info)
  44{
  45	struct task_struct *tracer;
  46	struct aa_label *tracerl = NULL;
  47	int error = 0;
  48
  49	rcu_read_lock();
  50	tracer = ptrace_parent(current);
  51	if (tracer)
  52		/* released below */
  53		tracerl = aa_get_task_label(tracer);
  54
  55	/* not ptraced */
  56	if (!tracer || unconfined(tracerl))
  57		goto out;
  58
  59	error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
  60
  61out:
  62	rcu_read_unlock();
  63	aa_put_label(tracerl);
  64
  65	if (error)
  66		*info = "ptrace prevents transition";
  67	return error;
  68}
  69
  70/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
  71 * specifically this is an exact copy of aa_label_match except
  72 * aa_compute_perms is replaced with aa_compute_fperms
  73 * and policy.dfa with file.dfa
  74 ****/
  75/* match a profile and its associated ns component if needed
  76 * Assumes visibility test has already been done.
  77 * If a subns profile is not to be matched should be prescreened with
  78 * visibility test.
  79 */
  80static inline aa_state_t match_component(struct aa_profile *profile,
  81					 struct aa_profile *tp,
  82					 bool stack, aa_state_t state)
  83{
  84	struct aa_ruleset *rules = list_first_entry(&profile->rules,
  85						    typeof(*rules), list);
  86	const char *ns_name;
  87
  88	if (stack)
  89		state = aa_dfa_match(rules->file.dfa, state, "&");
  90	if (profile->ns == tp->ns)
  91		return aa_dfa_match(rules->file.dfa, state, tp->base.hname);
  92
  93	/* try matching with namespace name and then profile */
  94	ns_name = aa_ns_name(profile->ns, tp->ns, true);
  95	state = aa_dfa_match_len(rules->file.dfa, state, ":", 1);
  96	state = aa_dfa_match(rules->file.dfa, state, ns_name);
  97	state = aa_dfa_match_len(rules->file.dfa, state, ":", 1);
  98	return aa_dfa_match(rules->file.dfa, state, tp->base.hname);
  99}
 100
 101/**
 102 * label_compound_match - find perms for full compound label
 103 * @profile: profile to find perms for
 104 * @label: label to check access permissions for
 105 * @stack: whether this is a stacking request
 106 * @state: state to start match in
 107 * @subns: whether to do permission checks on components in a subns
 108 * @request: permissions to request
 109 * @perms: perms struct to set
 110 *
 111 * Returns: 0 on success else ERROR
 112 *
 113 * For the label A//&B//&C this does the perm match for A//&B//&C
 114 * @perms should be preinitialized with allperms OR a previous permission
 115 *        check to be stacked.
 116 */
 117static int label_compound_match(struct aa_profile *profile,
 118				struct aa_label *label, bool stack,
 119				aa_state_t state, bool subns, u32 request,
 120				struct aa_perms *perms)
 121{
 122	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 123						    typeof(*rules), list);
 124	struct aa_profile *tp;
 125	struct label_it i;
 126	struct path_cond cond = { };
 127
 128	/* find first subcomponent that is visible */
 129	label_for_each(i, label, tp) {
 130		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 131			continue;
 132		state = match_component(profile, tp, stack, state);
 133		if (!state)
 134			goto fail;
 135		goto next;
 136	}
 137
 138	/* no component visible */
 139	*perms = allperms;
 140	return 0;
 141
 142next:
 143	label_for_each_cont(i, label, tp) {
 144		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 145			continue;
 146		state = aa_dfa_match(rules->file.dfa, state, "//&");
 147		state = match_component(profile, tp, false, state);
 148		if (!state)
 149			goto fail;
 150	}
 151	*perms = *(aa_lookup_fperms(&(rules->file), state, &cond));
 152	aa_apply_modes_to_perms(profile, perms);
 153	if ((perms->allow & request) != request)
 154		return -EACCES;
 155
 156	return 0;
 157
 158fail:
 159	*perms = nullperms;
 160	return -EACCES;
 161}
 162
 163/**
 164 * label_components_match - find perms for all subcomponents of a label
 165 * @profile: profile to find perms for
 166 * @label: label to check access permissions for
 167 * @stack: whether this is a stacking request
 168 * @start: state to start match in
 169 * @subns: whether to do permission checks on components in a subns
 170 * @request: permissions to request
 171 * @perms: an initialized perms struct to add accumulation to
 172 *
 173 * Returns: 0 on success else ERROR
 174 *
 175 * For the label A//&B//&C this does the perm match for each of A and B and C
 176 * @perms should be preinitialized with allperms OR a previous permission
 177 *        check to be stacked.
 178 */
 179static int label_components_match(struct aa_profile *profile,
 180				  struct aa_label *label, bool stack,
 181				  aa_state_t start, bool subns, u32 request,
 182				  struct aa_perms *perms)
 183{
 184	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 185						    typeof(*rules), list);
 186	struct aa_profile *tp;
 187	struct label_it i;
 188	struct aa_perms tmp;
 189	struct path_cond cond = { };
 190	aa_state_t state = 0;
 191
 192	/* find first subcomponent to test */
 193	label_for_each(i, label, tp) {
 194		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 195			continue;
 196		state = match_component(profile, tp, stack, start);
 197		if (!state)
 198			goto fail;
 199		goto next;
 200	}
 201
 202	/* no subcomponents visible - no change in perms */
 203	return 0;
 204
 205next:
 206	tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
 207	aa_apply_modes_to_perms(profile, &tmp);
 208	aa_perms_accum(perms, &tmp);
 209	label_for_each_cont(i, label, tp) {
 210		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 211			continue;
 212		state = match_component(profile, tp, stack, start);
 213		if (!state)
 214			goto fail;
 215		tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
 216		aa_apply_modes_to_perms(profile, &tmp);
 217		aa_perms_accum(perms, &tmp);
 218	}
 219
 220	if ((perms->allow & request) != request)
 221		return -EACCES;
 222
 223	return 0;
 224
 225fail:
 226	*perms = nullperms;
 227	return -EACCES;
 228}
 229
 230/**
 231 * label_match - do a multi-component label match
 232 * @profile: profile to match against (NOT NULL)
 233 * @label: label to match (NOT NULL)
 234 * @stack: whether this is a stacking request
 235 * @state: state to start in
 236 * @subns: whether to match subns components
 237 * @request: permission request
 238 * @perms: Returns computed perms (NOT NULL)
 239 *
 240 * Returns: the state the match finished in, may be the none matching state
 241 */
 242static int label_match(struct aa_profile *profile, struct aa_label *label,
 243		       bool stack, aa_state_t state, bool subns, u32 request,
 244		       struct aa_perms *perms)
 245{
 246	int error;
 247
 248	*perms = nullperms;
 249	error = label_compound_match(profile, label, stack, state, subns,
 250				     request, perms);
 251	if (!error)
 252		return error;
 253
 254	*perms = allperms;
 255	return label_components_match(profile, label, stack, state, subns,
 256				      request, perms);
 257}
 258
 259/******* end TODO: dedup *****/
 260
 261/**
 262 * change_profile_perms - find permissions for change_profile
 263 * @profile: the current profile  (NOT NULL)
 264 * @target: label to transition to (NOT NULL)
 265 * @stack: whether this is a stacking request
 266 * @request: requested perms
 267 * @start: state to start matching in
 268 *
 269 *
 270 * Returns: permission set
 271 *
 272 * currently only matches full label A//&B//&C or individual components A, B, C
 273 * not arbitrary combinations. Eg. A//&B, C
 274 */
 275static int change_profile_perms(struct aa_profile *profile,
 276				struct aa_label *target, bool stack,
 277				u32 request, aa_state_t start,
 278				struct aa_perms *perms)
 279{
 280	if (profile_unconfined(profile)) {
 281		perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
 282		perms->audit = perms->quiet = perms->kill = 0;
 283		return 0;
 
 
 
 
 
 
 
 
 
 
 
 284	}
 285
 286	/* TODO: add profile in ns screening */
 287	return label_match(profile, target, stack, start, true, request, perms);
 288}
 289
 290/**
 291 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
 292 * @bprm: binprm struct for the process to validate
 293 * @profile: profile to match against (NOT NULL)
 294 * @state: state to start match in
 295 *
 296 * Returns: number of extended attributes that matched, or < 0 on error
 297 */
 298static int aa_xattrs_match(const struct linux_binprm *bprm,
 299			   struct aa_profile *profile, aa_state_t state)
 300{
 301	int i;
 302	struct dentry *d;
 303	char *value = NULL;
 304	struct aa_attachment *attach = &profile->attach;
 305	int size, value_size = 0, ret = attach->xattr_count;
 306
 307	if (!bprm || !attach->xattr_count)
 308		return 0;
 309	might_sleep();
 310
 311	/* transition from exec match to xattr set */
 312	state = aa_dfa_outofband_transition(attach->xmatch.dfa, state);
 313	d = bprm->file->f_path.dentry;
 314
 315	for (i = 0; i < attach->xattr_count; i++) {
 316		size = vfs_getxattr_alloc(&init_user_ns, d, attach->xattrs[i],
 317					  &value, value_size, GFP_KERNEL);
 318		if (size >= 0) {
 319			u32 index, perm;
 320
 321			/*
 322			 * Check the xattr presence before value. This ensure
 323			 * that not present xattr can be distinguished from a 0
 324			 * length value or rule that matches any value
 325			 */
 326			state = aa_dfa_null_transition(attach->xmatch.dfa,
 327						       state);
 328			/* Check xattr value */
 329			state = aa_dfa_match_len(attach->xmatch.dfa, state,
 330						 value, size);
 331			index = ACCEPT_TABLE(attach->xmatch.dfa)[state];
 332			perm = attach->xmatch.perms[index].allow;
 333			if (!(perm & MAY_EXEC)) {
 334				ret = -EINVAL;
 335				goto out;
 336			}
 337		}
 338		/* transition to next element */
 339		state = aa_dfa_outofband_transition(attach->xmatch.dfa, state);
 340		if (size < 0) {
 341			/*
 342			 * No xattr match, so verify if transition to
 343			 * next element was valid. IFF so the xattr
 344			 * was optional.
 345			 */
 346			if (!state) {
 347				ret = -EINVAL;
 348				goto out;
 349			}
 350			/* don't count missing optional xattr as matched */
 351			ret--;
 352		}
 353	}
 354
 355out:
 356	kfree(value);
 357	return ret;
 358}
 359
 360/**
 361 * find_attach - do attachment search for unconfined processes
 362 * @bprm - binprm structure of transitioning task
 363 * @ns: the current namespace  (NOT NULL)
 364 * @head - profile list to walk  (NOT NULL)
 365 * @name - to match against  (NOT NULL)
 366 * @info - info message if there was an error (NOT NULL)
 367 *
 368 * Do a linear search on the profiles in the list.  There is a matching
 369 * preference where an exact match is preferred over a name which uses
 370 * expressions to match, and matching expressions with the greatest
 371 * xmatch_len are preferred.
 372 *
 373 * Requires: @head not be shared or have appropriate locks held
 374 *
 375 * Returns: label or NULL if no match found
 376 */
 377static struct aa_label *find_attach(const struct linux_binprm *bprm,
 378				    struct aa_ns *ns, struct list_head *head,
 379				    const char *name, const char **info)
 380{
 381	int candidate_len = 0, candidate_xattrs = 0;
 382	bool conflict = false;
 383	struct aa_profile *profile, *candidate = NULL;
 384
 385	AA_BUG(!name);
 386	AA_BUG(!head);
 387
 388	rcu_read_lock();
 389restart:
 390	list_for_each_entry_rcu(profile, head, base.list) {
 391		struct aa_attachment *attach = &profile->attach;
 392
 393		if (profile->label.flags & FLAG_NULL &&
 394		    &profile->label == ns_unconfined(profile->ns))
 395			continue;
 396
 397		/* Find the "best" matching profile. Profiles must
 398		 * match the path and extended attributes (if any)
 399		 * associated with the file. A more specific path
 400		 * match will be preferred over a less specific one,
 401		 * and a match with more matching extended attributes
 402		 * will be preferred over one with fewer. If the best
 403		 * match has both the same level of path specificity
 404		 * and the same number of matching extended attributes
 405		 * as another profile, signal a conflict and refuse to
 406		 * match.
 407		 */
 408		if (attach->xmatch.dfa) {
 409			unsigned int count;
 410			aa_state_t state;
 411			u32 index, perm;
 412
 413			state = aa_dfa_leftmatch(attach->xmatch.dfa,
 414					attach->xmatch.start[AA_CLASS_XMATCH],
 415					name, &count);
 416			index = ACCEPT_TABLE(attach->xmatch.dfa)[state];
 417			perm = attach->xmatch.perms[index].allow;
 418			/* any accepting state means a valid match. */
 419			if (perm & MAY_EXEC) {
 420				int ret = 0;
 
 
 
 
 
 
 421
 422				if (count < candidate_len)
 423					continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
 424
 425				if (bprm && attach->xattr_count) {
 426					long rev = READ_ONCE(ns->revision);
 
 427
 428					if (!aa_get_profile_not0(profile))
 429						goto restart;
 430					rcu_read_unlock();
 431					ret = aa_xattrs_match(bprm, profile,
 432							      state);
 433					rcu_read_lock();
 434					aa_put_profile(profile);
 435					if (rev !=
 436					    READ_ONCE(ns->revision))
 437						/* policy changed */
 438						goto restart;
 439					/*
 440					 * Fail matching if the xattrs don't
 441					 * match
 442					 */
 443					if (ret < 0)
 444						continue;
 445				}
 446				/*
 447				 * TODO: allow for more flexible best match
 448				 *
 449				 * The new match isn't more specific
 450				 * than the current best match
 451				 */
 452				if (count == candidate_len &&
 453				    ret <= candidate_xattrs) {
 454					/* Match is equivalent, so conflict */
 455					if (ret == candidate_xattrs)
 456						conflict = true;
 457					continue;
 458				}
 459
 460				/* Either the same length with more matching
 461				 * xattrs, or a longer match
 462				 */
 463				candidate = profile;
 464				candidate_len = max(count, attach->xmatch_len);
 465				candidate_xattrs = ret;
 466				conflict = false;
 467			}
 468		} else if (!strcmp(profile->base.name, name)) {
 469			/*
 470			 * old exact non-re match, without conditionals such
 471			 * as xattrs. no more searching required
 472			 */
 473			candidate = profile;
 474			goto out;
 475		}
 476	}
 
 
 
 
 
 
 
 477
 478	if (!candidate || conflict) {
 479		if (conflict)
 480			*info = "conflicting profile attachments";
 481		rcu_read_unlock();
 482		return NULL;
 
 
 
 
 
 
 
 483	}
 484
 485out:
 486	candidate = aa_get_newest_profile(candidate);
 487	rcu_read_unlock();
 488
 489	return &candidate->label;
 490}
 491
 492static const char *next_name(int xtype, const char *name)
 493{
 494	return NULL;
 495}
 496
 497/**
 498 * x_table_lookup - lookup an x transition name via transition table
 499 * @profile: current profile (NOT NULL)
 500 * @xindex: index into x transition table
 501 * @name: returns: name tested to find label (NOT NULL)
 502 *
 503 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
 504 */
 505struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
 506				const char **name)
 507{
 508	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 509						    typeof(*rules), list);
 510	struct aa_label *label = NULL;
 511	u32 xtype = xindex & AA_X_TYPE_MASK;
 512	int index = xindex & AA_X_INDEX_MASK;
 
 513
 514	AA_BUG(!name);
 
 
 
 
 515
 516	/* index is guaranteed to be in range, validated at load time */
 517	/* TODO: move lookup parsing to unpack time so this is a straight
 518	 *       index into the resultant label
 519	 */
 520	for (*name = rules->file.trans.table[index]; !label && *name;
 521	     *name = next_name(xtype, *name)) {
 522		if (xindex & AA_X_CHILD) {
 523			struct aa_profile *new_profile;
 524			/* release by caller */
 525			new_profile = aa_find_child(profile, *name);
 526			if (new_profile)
 527				label = &new_profile->label;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 528			continue;
 
 
 
 529		}
 530		label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
 531				       true, false);
 532		if (IS_ERR(label))
 533			label = NULL;
 534	}
 535
 536	/* released by caller */
 537
 538	return label;
 539}
 540
 541/**
 542 * x_to_label - get target label for a given xindex
 543 * @profile: current profile  (NOT NULL)
 544 * @bprm: binprm structure of transitioning task
 545 * @name: name to lookup (NOT NULL)
 546 * @xindex: index into x transition table
 547 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
 548 *
 549 * find label for a transition index
 550 *
 551 * Returns: refcounted label or NULL if not found available
 552 */
 553static struct aa_label *x_to_label(struct aa_profile *profile,
 554				   const struct linux_binprm *bprm,
 555				   const char *name, u32 xindex,
 556				   const char **lookupname,
 557				   const char **info)
 558{
 559	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 560						    typeof(*rules), list);
 561	struct aa_label *new = NULL;
 562	struct aa_ns *ns = profile->ns;
 563	u32 xtype = xindex & AA_X_TYPE_MASK;
 564	const char *stack = NULL;
 565
 566	switch (xtype) {
 567	case AA_X_NONE:
 568		/* fail exec unless ix || ux fallback - handled by caller */
 569		*lookupname = NULL;
 570		break;
 571	case AA_X_TABLE:
 572		/* TODO: fix when perm mapping done at unload */
 573		stack = rules->file.trans.table[xindex & AA_X_INDEX_MASK];
 574		if (*stack != '&') {
 575			/* released by caller */
 576			new = x_table_lookup(profile, xindex, lookupname);
 577			stack = NULL;
 578			break;
 579		}
 580		fallthrough;	/* to X_NAME */
 581	case AA_X_NAME:
 582		if (xindex & AA_X_CHILD)
 583			/* released by caller */
 584			new = find_attach(bprm, ns, &profile->base.profiles,
 585					  name, info);
 586		else
 587			/* released by caller */
 588			new = find_attach(bprm, ns, &ns->base.profiles,
 589					  name, info);
 590		*lookupname = name;
 
 
 
 591		break;
 592	}
 593
 594	if (!new) {
 595		if (xindex & AA_X_INHERIT) {
 596			/* (p|c|n)ix - don't change profile but do
 597			 * use the newest version
 598			 */
 599			*info = "ix fallback";
 600			/* no profile && no error */
 601			new = aa_get_newest_label(&profile->label);
 602		} else if (xindex & AA_X_UNCONFINED) {
 603			new = aa_get_newest_label(ns_unconfined(profile->ns));
 604			*info = "ux fallback";
 605		}
 606	}
 607
 608	if (new && stack) {
 609		/* base the stack on post domain transition */
 610		struct aa_label *base = new;
 611
 612		new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
 613		if (IS_ERR(new))
 614			new = NULL;
 615		aa_put_label(base);
 616	}
 617
 618	/* released by caller */
 619	return new;
 620}
 621
 622static struct aa_label *profile_transition(struct aa_profile *profile,
 623					   const struct linux_binprm *bprm,
 624					   char *buffer, struct path_cond *cond,
 625					   bool *secure_exec)
 
 
 
 626{
 627	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 628						    typeof(*rules), list);
 629	struct aa_label *new = NULL;
 630	const char *info = NULL, *name = NULL, *target = NULL;
 631	aa_state_t state = rules->file.start[AA_CLASS_FILE];
 632	struct aa_perms perms = {};
 633	bool nonewprivs = false;
 
 
 
 
 634	int error = 0;
 635
 636	AA_BUG(!profile);
 637	AA_BUG(!bprm);
 638	AA_BUG(!buffer);
 
 
 639
 640	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 641			     &name, &info, profile->disconnected);
 
 
 
 
 
 
 
 
 
 642	if (error) {
 643		if (profile_unconfined(profile) ||
 644		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 645			AA_DEBUG("name lookup ix on error");
 646			error = 0;
 647			new = aa_get_newest_label(&profile->label);
 648		}
 649		name = bprm->filename;
 650		goto audit;
 651	}
 652
 653	if (profile_unconfined(profile)) {
 654		new = find_attach(bprm, profile->ns,
 655				  &profile->ns->base.profiles, name, &info);
 656		if (new) {
 657			AA_DEBUG("unconfined attached to new label");
 658			return new;
 659		}
 660		AA_DEBUG("unconfined exec no attachment");
 661		return aa_get_newest_label(&profile->label);
 
 
 
 
 
 
 
 
 
 662	}
 663
 664	/* find exec permissions for name */
 665	state = aa_str_perms(&(rules->file), state, name, cond, &perms);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 666	if (perms.allow & MAY_EXEC) {
 667		/* exec permission determine how to transition */
 668		new = x_to_label(profile, bprm, name, perms.xindex, &target,
 669				 &info);
 670		if (new && new->proxy == profile->label.proxy && info) {
 671			/* hack ix fallback - improve how this is detected */
 672			goto audit;
 673		} else if (!new) {
 674			error = -EACCES;
 675			info = "profile transition not found";
 676			/* remove MAY_EXEC to audit as failure */
 677			perms.allow &= ~MAY_EXEC;
 
 
 
 
 
 
 
 
 
 678		}
 679	} else if (COMPLAIN_MODE(profile)) {
 680		/* no exec permission - learning mode */
 681		struct aa_profile *new_profile = NULL;
 682
 683		new_profile = aa_new_learning_profile(profile, false, name,
 684						      GFP_KERNEL);
 685		if (!new_profile) {
 686			error = -ENOMEM;
 687			info = "could not create null profile";
 688		} else {
 689			error = -EACCES;
 690			new = &new_profile->label;
 691		}
 692		perms.xindex |= AA_X_UNSAFE;
 693	} else
 694		/* fail exec */
 695		error = -EACCES;
 696
 697	if (!new)
 698		goto audit;
 699
 700
 701	if (!(perms.xindex & AA_X_UNSAFE)) {
 702		if (DEBUG_ON) {
 703			dbg_printk("apparmor: scrubbing environment variables"
 704				   " for %s profile=", name);
 705			aa_label_printk(new, GFP_KERNEL);
 706			dbg_printk("\n");
 707		}
 708		*secure_exec = true;
 709	}
 710
 711audit:
 712	aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
 713		      cond->uid, info, error);
 714	if (!new || nonewprivs) {
 715		aa_put_label(new);
 716		return ERR_PTR(error);
 717	}
 718
 719	return new;
 720}
 721
 722static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
 723			  bool stack, const struct linux_binprm *bprm,
 724			  char *buffer, struct path_cond *cond,
 725			  bool *secure_exec)
 726{
 727	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 728						    typeof(*rules), list);
 729	aa_state_t state = rules->file.start[AA_CLASS_FILE];
 730	struct aa_perms perms = {};
 731	const char *xname = NULL, *info = "change_profile onexec";
 732	int error = -EACCES;
 733
 734	AA_BUG(!profile);
 735	AA_BUG(!onexec);
 736	AA_BUG(!bprm);
 737	AA_BUG(!buffer);
 738
 739	if (profile_unconfined(profile)) {
 740		/* change_profile on exec already granted */
 741		/*
 742		 * NOTE: Domain transitions from unconfined are allowed
 743		 * even when no_new_privs is set because this aways results
 744		 * in a further reduction of permissions.
 745		 */
 746		return 0;
 747	}
 748
 749	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
 750			     &xname, &info, profile->disconnected);
 751	if (error) {
 752		if (profile_unconfined(profile) ||
 753		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
 754			AA_DEBUG("name lookup ix on error");
 755			error = 0;
 756		}
 757		xname = bprm->filename;
 758		goto audit;
 759	}
 760
 761	/* find exec permissions for name */
 762	state = aa_str_perms(&(rules->file), state, xname, cond, &perms);
 763	if (!(perms.allow & AA_MAY_ONEXEC)) {
 764		info = "no change_onexec valid for executable";
 765		goto audit;
 766	}
 767	/* test if this exec can be paired with change_profile onexec.
 768	 * onexec permission is linked to exec with a standard pairing
 769	 * exec\0change_profile
 
 
 770	 */
 771	state = aa_dfa_null_transition(rules->file.dfa, state);
 772	error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
 773				     state, &perms);
 774	if (error) {
 775		perms.allow &= ~AA_MAY_ONEXEC;
 776		goto audit;
 777	}
 
 
 
 
 
 
 
 778
 779	if (!(perms.xindex & AA_X_UNSAFE)) {
 780		if (DEBUG_ON) {
 781			dbg_printk("apparmor: scrubbing environment "
 782				   "variables for %s label=", xname);
 783			aa_label_printk(onexec, GFP_KERNEL);
 784			dbg_printk("\n");
 785		}
 786		*secure_exec = true;
 787	}
 788
 789audit:
 790	return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
 791			     NULL, onexec, cond->uid, info, error);
 792}
 793
 794/* ensure none ns domain transitions are correctly applied with onexec */
 
 
 795
 796static struct aa_label *handle_onexec(struct aa_label *label,
 797				      struct aa_label *onexec, bool stack,
 798				      const struct linux_binprm *bprm,
 799				      char *buffer, struct path_cond *cond,
 800				      bool *unsafe)
 801{
 802	struct aa_profile *profile;
 803	struct aa_label *new;
 804	int error;
 805
 806	AA_BUG(!label);
 807	AA_BUG(!onexec);
 808	AA_BUG(!bprm);
 809	AA_BUG(!buffer);
 810
 811	if (!stack) {
 812		error = fn_for_each_in_ns(label, profile,
 813				profile_onexec(profile, onexec, stack,
 814					       bprm, buffer, cond, unsafe));
 815		if (error)
 816			return ERR_PTR(error);
 817		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 818				aa_get_newest_label(onexec),
 819				profile_transition(profile, bprm, buffer,
 820						   cond, unsafe));
 821
 822	} else {
 823		/* TODO: determine how much we want to loosen this */
 824		error = fn_for_each_in_ns(label, profile,
 825				profile_onexec(profile, onexec, stack, bprm,
 826					       buffer, cond, unsafe));
 827		if (error)
 828			return ERR_PTR(error);
 829		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
 830				aa_label_merge(&profile->label, onexec,
 831					       GFP_KERNEL),
 832				profile_transition(profile, bprm, buffer,
 833						   cond, unsafe));
 834	}
 835
 836	if (new)
 837		return new;
 838
 839	/* TODO: get rid of GLOBAL_ROOT_UID */
 840	error = fn_for_each_in_ns(label, profile,
 841			aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
 842				      AA_MAY_ONEXEC, bprm->filename, NULL,
 843				      onexec, GLOBAL_ROOT_UID,
 844				      "failed to build target label", -ENOMEM));
 845	return ERR_PTR(error);
 846}
 847
 848/**
 849 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
 850 * @bprm: binprm for the exec  (NOT NULL)
 851 *
 852 * Returns: %0 or error on failure
 853 *
 854 * TODO: once the other paths are done see if we can't refactor into a fn
 855 */
 856int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
 857{
 858	struct aa_task_ctx *ctx;
 859	struct aa_label *label, *new = NULL;
 860	struct aa_profile *profile;
 861	char *buffer = NULL;
 862	const char *info = NULL;
 863	int error = 0;
 864	bool unsafe = false;
 865	vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_user_ns(bprm->file),
 866					    file_inode(bprm->file));
 867	struct path_cond cond = {
 868		vfsuid_into_kuid(vfsuid),
 869		file_inode(bprm->file)->i_mode
 870	};
 871
 872	ctx = task_ctx(current);
 873	AA_BUG(!cred_label(bprm->cred));
 874	AA_BUG(!ctx);
 875
 876	label = aa_get_newest_label(cred_label(bprm->cred));
 877
 878	/*
 879	 * Detect no new privs being set, and store the label it
 880	 * occurred under. Ideally this would happen when nnp
 881	 * is set but there isn't a good way to do that yet.
 882	 *
 883	 * Testing for unconfined must be done before the subset test
 884	 */
 885	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
 886	    !ctx->nnp)
 887		ctx->nnp = aa_get_label(label);
 888
 889	/* buffer freed below, name is pointer into buffer */
 890	buffer = aa_get_buffer(false);
 891	if (!buffer) {
 892		error = -ENOMEM;
 893		goto done;
 894	}
 895
 896	/* Test for onexec first as onexec override other x transitions. */
 897	if (ctx->onexec)
 898		new = handle_onexec(label, ctx->onexec, ctx->token,
 899				    bprm, buffer, &cond, &unsafe);
 900	else
 901		new = fn_label_build(label, profile, GFP_KERNEL,
 902				profile_transition(profile, bprm, buffer,
 903						   &cond, &unsafe));
 904
 905	AA_BUG(!new);
 906	if (IS_ERR(new)) {
 907		error = PTR_ERR(new);
 908		goto done;
 909	} else if (!new) {
 910		error = -ENOMEM;
 911		goto done;
 912	}
 913
 914	/* Policy has specified a domain transitions. If no_new_privs and
 915	 * confined ensure the transition is to confinement that is subset
 916	 * of the confinement when the task entered no new privs.
 917	 *
 918	 * NOTE: Domain transitions from unconfined and to stacked
 919	 * subsets are allowed even when no_new_privs is set because this
 920	 * aways results in a further reduction of permissions.
 921	 */
 922	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
 923	    !unconfined(label) &&
 924	    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
 925		error = -EPERM;
 926		info = "no new privs";
 927		goto audit;
 928	}
 929
 930	if (bprm->unsafe & LSM_UNSAFE_SHARE) {
 931		/* FIXME: currently don't mediate shared state */
 932		;
 933	}
 934
 935	if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
 936		/* TODO: test needs to be profile of label to new */
 937		error = may_change_ptraced_domain(new, &info);
 938		if (error)
 939			goto audit;
 940	}
 941
 942	if (unsafe) {
 943		if (DEBUG_ON) {
 944			dbg_printk("scrubbing environment variables for %s "
 945				   "label=", bprm->filename);
 946			aa_label_printk(new, GFP_KERNEL);
 947			dbg_printk("\n");
 948		}
 949		bprm->secureexec = 1;
 950	}
 951
 952	if (label->proxy != new->proxy) {
 953		/* when transitioning clear unsafe personality bits */
 954		if (DEBUG_ON) {
 955			dbg_printk("apparmor: clearing unsafe personality "
 956				   "bits. %s label=", bprm->filename);
 957			aa_label_printk(new, GFP_KERNEL);
 958			dbg_printk("\n");
 959		}
 960		bprm->per_clear |= PER_CLEAR_ON_SETID;
 961	}
 962	aa_put_label(cred_label(bprm->cred));
 963	/* transfer reference, released when cred is freed */
 964	set_cred_label(bprm->cred, new);
 965
 966done:
 967	aa_put_label(label);
 968	aa_put_buffer(buffer);
 969
 970	return error;
 971
 972audit:
 973	error = fn_for_each(label, profile,
 974			aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
 975				      bprm->filename, NULL, new,
 976				      vfsuid_into_kuid(vfsuid), info, error));
 977	aa_put_label(new);
 978	goto done;
 979}
 980
 981/*
 982 * Functions for self directed profile change
 
 983 */
 984
 985
 986/* helper fn for change_hat
 987 *
 988 * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
 989 */
 990static struct aa_label *build_change_hat(struct aa_profile *profile,
 991					 const char *name, bool sibling)
 992{
 993	struct aa_profile *root, *hat = NULL;
 994	const char *info = NULL;
 995	int error = 0;
 996
 997	if (sibling && PROFILE_IS_HAT(profile)) {
 998		root = aa_get_profile_rcu(&profile->parent);
 999	} else if (!sibling && !PROFILE_IS_HAT(profile)) {
1000		root = aa_get_profile(profile);
1001	} else {
1002		info = "conflicting target types";
1003		error = -EPERM;
1004		goto audit;
1005	}
1006
1007	hat = aa_find_child(root, name);
1008	if (!hat) {
1009		error = -ENOENT;
1010		if (COMPLAIN_MODE(profile)) {
1011			hat = aa_new_learning_profile(profile, true, name,
1012						      GFP_KERNEL);
1013			if (!hat) {
1014				info = "failed null profile create";
1015				error = -ENOMEM;
1016			}
1017		}
1018	}
1019	aa_put_profile(root);
1020
1021audit:
1022	aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1023		      name, hat ? hat->base.hname : NULL,
1024		      hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1025		      error);
1026	if (!hat || (error && error != -ENOENT))
1027		return ERR_PTR(error);
1028	/* if hat && error - complain mode, already audited and we adjust for
1029	 * complain mode allow by returning hat->label
1030	 */
1031	return &hat->label;
1032}
1033
1034/* helper fn for changing into a hat
1035 *
1036 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1037 */
1038static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1039				   int count, int flags)
1040{
1041	struct aa_profile *profile, *root, *hat = NULL;
1042	struct aa_label *new;
1043	struct label_it it;
1044	bool sibling = false;
1045	const char *name, *info = NULL;
1046	int i, error;
1047
1048	AA_BUG(!label);
1049	AA_BUG(!hats);
1050	AA_BUG(count < 1);
1051
1052	if (PROFILE_IS_HAT(labels_profile(label)))
1053		sibling = true;
1054
1055	/*find first matching hat */
1056	for (i = 0; i < count && !hat; i++) {
1057		name = hats[i];
1058		label_for_each_in_ns(it, labels_ns(label), label, profile) {
1059			if (sibling && PROFILE_IS_HAT(profile)) {
1060				root = aa_get_profile_rcu(&profile->parent);
1061			} else if (!sibling && !PROFILE_IS_HAT(profile)) {
1062				root = aa_get_profile(profile);
1063			} else {	/* conflicting change type */
1064				info = "conflicting targets types";
1065				error = -EPERM;
1066				goto fail;
1067			}
1068			hat = aa_find_child(root, name);
1069			aa_put_profile(root);
1070			if (!hat) {
1071				if (!COMPLAIN_MODE(profile))
1072					goto outer_continue;
1073				/* complain mode succeed as if hat */
1074			} else if (!PROFILE_IS_HAT(hat)) {
1075				info = "target not hat";
1076				error = -EPERM;
1077				aa_put_profile(hat);
1078				goto fail;
1079			}
1080			aa_put_profile(hat);
1081		}
1082		/* found a hat for all profiles in ns */
1083		goto build;
1084outer_continue:
1085	;
1086	}
1087	/* no hats that match, find appropriate error
1088	 *
1089	 * In complain mode audit of the failure is based off of the first
1090	 * hat supplied.  This is done due how userspace interacts with
1091	 * change_hat.
1092	 */
1093	name = NULL;
1094	label_for_each_in_ns(it, labels_ns(label), label, profile) {
1095		if (!list_empty(&profile->base.profiles)) {
1096			info = "hat not found";
1097			error = -ENOENT;
1098			goto fail;
1099		}
1100	}
1101	info = "no hats defined";
1102	error = -ECHILD;
1103
1104fail:
1105	label_for_each_in_ns(it, labels_ns(label), label, profile) {
1106		/*
1107		 * no target as it has failed to be found or built
1108		 *
1109		 * change_hat uses probing and should not log failures
1110		 * related to missing hats
1111		 */
1112		/* TODO: get rid of GLOBAL_ROOT_UID */
1113		if (count > 1 || COMPLAIN_MODE(profile)) {
1114			aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1115				      AA_MAY_CHANGEHAT, name, NULL, NULL,
1116				      GLOBAL_ROOT_UID, info, error);
1117		}
1118	}
1119	return ERR_PTR(error);
1120
1121build:
1122	new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1123				   build_change_hat(profile, name, sibling),
1124				   aa_get_label(&profile->label));
1125	if (!new) {
1126		info = "label build failed";
1127		error = -ENOMEM;
1128		goto fail;
1129	} /* else if (IS_ERR) build_change_hat has logged error so return new */
1130
1131	return new;
 
 
1132}
1133
1134/**
1135 * aa_change_hat - change hat to/from subprofile
1136 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1137 * @count: number of hat names in @hats
1138 * @token: magic value to validate the hat change
1139 * @flags: flags affecting behavior of the change
1140 *
1141 * Returns %0 on success, error otherwise.
1142 *
1143 * Change to the first profile specified in @hats that exists, and store
1144 * the @hat_magic in the current task context.  If the count == 0 and the
1145 * @token matches that stored in the current task context, return to the
1146 * top level profile.
1147 *
1148 * change_hat only applies to profiles in the current ns, and each profile
1149 * in the ns must make the same transition otherwise change_hat will fail.
1150 */
1151int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1152{
1153	const struct cred *cred;
1154	struct aa_task_ctx *ctx = task_ctx(current);
1155	struct aa_label *label, *previous, *new = NULL, *target = NULL;
1156	struct aa_profile *profile;
1157	struct aa_perms perms = {};
1158	const char *info = NULL;
 
1159	int error = 0;
1160
 
 
 
 
 
 
 
 
1161	/* released below */
1162	cred = get_current_cred();
1163	label = aa_get_newest_cred_label(cred);
1164	previous = aa_get_newest_label(ctx->previous);
1165
1166	/*
1167	 * Detect no new privs being set, and store the label it
1168	 * occurred under. Ideally this would happen when nnp
1169	 * is set but there isn't a good way to do that yet.
1170	 *
1171	 * Testing for unconfined must be done before the subset test
1172	 */
1173	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1174		ctx->nnp = aa_get_label(label);
1175
1176	if (unconfined(label)) {
1177		info = "unconfined can not change_hat";
1178		error = -EPERM;
1179		goto fail;
1180	}
1181
1182	if (count) {
1183		new = change_hat(label, hats, count, flags);
1184		AA_BUG(!new);
1185		if (IS_ERR(new)) {
1186			error = PTR_ERR(new);
1187			new = NULL;
1188			/* already audited */
1189			goto out;
1190		}
 
 
 
 
 
 
 
 
 
 
 
 
1191
1192		error = may_change_ptraced_domain(new, &info);
1193		if (error)
1194			goto fail;
 
 
 
 
 
1195
1196		/*
1197		 * no new privs prevents domain transitions that would
1198		 * reduce restrictions.
1199		 */
1200		if (task_no_new_privs(current) && !unconfined(label) &&
1201		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1202			/* not an apparmor denial per se, so don't log it */
1203			AA_DEBUG("no_new_privs - change_hat denied");
1204			error = -EPERM;
1205			goto out;
 
 
 
 
 
 
 
 
 
1206		}
1207
1208		if (flags & AA_CHANGE_TEST)
1209			goto out;
1210
1211		target = new;
1212		error = aa_set_current_hat(new, token);
1213		if (error == -EACCES)
1214			/* kill task in case of brute force attacks */
1215			goto kill;
1216	} else if (previous && !(flags & AA_CHANGE_TEST)) {
1217		/*
1218		 * no new privs prevents domain transitions that would
1219		 * reduce restrictions.
1220		 */
1221		if (task_no_new_privs(current) && !unconfined(label) &&
1222		    !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1223			/* not an apparmor denial per se, so don't log it */
1224			AA_DEBUG("no_new_privs - change_hat denied");
1225			error = -EPERM;
1226			goto out;
1227		}
1228
1229		/* Return to saved label.  Kill task if restore fails
 
 
 
 
 
 
 
 
 
 
1230		 * to avoid brute force attacks
1231		 */
1232		target = previous;
1233		error = aa_restore_previous_label(token);
1234		if (error) {
1235			if (error == -EACCES)
1236				goto kill;
1237			goto fail;
1238		}
1239	} /* else ignore @flags && restores when there is no saved profile */
 
 
 
 
1240
1241out:
1242	aa_put_label(new);
1243	aa_put_label(previous);
1244	aa_put_label(label);
1245	put_cred(cred);
1246
1247	return error;
1248
1249kill:
1250	info = "failed token match";
1251	perms.kill = AA_MAY_CHANGEHAT;
1252
1253fail:
1254	fn_for_each_in_ns(label, profile,
1255		aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1256			      AA_MAY_CHANGEHAT, NULL, NULL, target,
1257			      GLOBAL_ROOT_UID, info, error));
1258
1259	goto out;
1260}
1261
1262
1263static int change_profile_perms_wrapper(const char *op, const char *name,
1264					struct aa_profile *profile,
1265					struct aa_label *target, bool stack,
1266					u32 request, struct aa_perms *perms)
1267{
1268	struct aa_ruleset *rules = list_first_entry(&profile->rules,
1269						    typeof(*rules), list);
1270	const char *info = NULL;
1271	int error = 0;
1272
1273	if (!error)
1274		error = change_profile_perms(profile, target, stack, request,
1275					     rules->file.start[AA_CLASS_FILE],
1276					     perms);
1277	if (error)
1278		error = aa_audit_file(profile, perms, op, request, name,
1279				      NULL, target, GLOBAL_ROOT_UID, info,
1280				      error);
1281
1282	return error;
1283}
1284
1285/**
1286 * aa_change_profile - perform a one-way profile transition
1287 * @fqname: name of profile may include namespace (NOT NULL)
1288 * @flags: flags affecting change behavior
 
 
1289 *
1290 * Change to new profile @name.  Unlike with hats, there is no way
1291 * to change back.  If @name isn't specified the current profile name is
1292 * used.
1293 * If @onexec then the transition is delayed until
1294 * the next exec.
1295 *
1296 * Returns %0 on success, error otherwise.
1297 */
1298int aa_change_profile(const char *fqname, int flags)
 
1299{
1300	struct aa_label *label, *new = NULL, *target = NULL;
1301	struct aa_profile *profile;
1302	struct aa_perms perms = {};
1303	const char *info = NULL;
1304	const char *auditname = fqname;		/* retain leading & if stack */
1305	bool stack = flags & AA_CHANGE_STACK;
1306	struct aa_task_ctx *ctx = task_ctx(current);
1307	int error = 0;
1308	char *op;
1309	u32 request;
1310
1311	label = aa_get_current_label();
 
 
 
 
 
 
 
 
 
 
 
 
1312
1313	/*
1314	 * Detect no new privs being set, and store the label it
1315	 * occurred under. Ideally this would happen when nnp
1316	 * is set but there isn't a good way to do that yet.
1317	 *
1318	 * Testing for unconfined must be done before the subset test
1319	 */
1320	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1321		ctx->nnp = aa_get_label(label);
 
 
1322
1323	if (!fqname || !*fqname) {
1324		aa_put_label(label);
1325		AA_DEBUG("no profile name");
1326		return -EINVAL;
1327	}
 
 
 
 
 
 
 
 
1328
1329	if (flags & AA_CHANGE_ONEXEC) {
1330		request = AA_MAY_ONEXEC;
1331		if (stack)
1332			op = OP_STACK_ONEXEC;
1333		else
1334			op = OP_CHANGE_ONEXEC;
1335	} else {
1336		request = AA_MAY_CHANGE_PROFILE;
1337		if (stack)
1338			op = OP_STACK;
1339		else
1340			op = OP_CHANGE_PROFILE;
1341	}
1342
1343	if (*fqname == '&') {
1344		stack = true;
1345		/* don't have label_parse() do stacking */
1346		fqname++;
 
1347	}
1348	target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1349	if (IS_ERR(target)) {
1350		struct aa_profile *tprofile;
1351
1352		info = "label not found";
1353		error = PTR_ERR(target);
1354		target = NULL;
1355		/*
1356		 * TODO: fixme using labels_profile is not right - do profile
1357		 * per complain profile
1358		 */
1359		if ((flags & AA_CHANGE_TEST) ||
1360		    !COMPLAIN_MODE(labels_profile(label)))
1361			goto audit;
1362		/* released below */
1363		tprofile = aa_new_learning_profile(labels_profile(label), false,
1364						   fqname, GFP_KERNEL);
1365		if (!tprofile) {
1366			info = "failed null profile create";
1367			error = -ENOMEM;
1368			goto audit;
1369		}
1370		target = &tprofile->label;
1371		goto check;
1372	}
1373
1374	/*
1375	 * self directed transitions only apply to current policy ns
1376	 * TODO: currently requiring perms for stacking and straight change
1377	 *       stacking doesn't strictly need this. Determine how much
1378	 *       we want to loosen this restriction for stacking
1379	 *
1380	 * if (!stack) {
1381	 */
1382	error = fn_for_each_in_ns(label, profile,
1383			change_profile_perms_wrapper(op, auditname,
1384						     profile, target, stack,
1385						     request, &perms));
1386	if (error)
1387		/* auditing done in change_profile_perms_wrapper */
1388		goto out;
1389
1390	/* } */
1391
1392check:
1393	/* check if tracing task is allowed to trace target domain */
1394	error = may_change_ptraced_domain(target, &info);
1395	if (error && !fn_for_each_in_ns(label, profile,
1396					COMPLAIN_MODE(profile)))
1397		goto audit;
1398
1399	/* TODO: add permission check to allow this
1400	 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1401	 *      info = "not a single threaded task";
1402	 *      error = -EACCES;
1403	 *      goto audit;
1404	 * }
1405	 */
1406	if (flags & AA_CHANGE_TEST)
1407		goto out;
1408
1409	/* stacking is always a subset, so only check the nonstack case */
1410	if (!stack) {
1411		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1412					   aa_get_label(target),
1413					   aa_get_label(&profile->label));
1414		/*
1415		 * no new privs prevents domain transitions that would
1416		 * reduce restrictions.
1417		 */
1418		if (task_no_new_privs(current) && !unconfined(label) &&
1419		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1420			/* not an apparmor denial per se, so don't log it */
1421			AA_DEBUG("no_new_privs - change_hat denied");
1422			error = -EPERM;
1423			goto out;
1424		}
1425	}
1426
1427	if (!(flags & AA_CHANGE_ONEXEC)) {
1428		/* only transition profiles in the current ns */
1429		if (stack)
1430			new = aa_label_merge(label, target, GFP_KERNEL);
1431		if (IS_ERR_OR_NULL(new)) {
1432			info = "failed to build target label";
1433			if (!new)
1434				error = -ENOMEM;
1435			else
1436				error = PTR_ERR(new);
1437			new = NULL;
1438			perms.allow = 0;
1439			goto audit;
1440		}
1441		error = aa_replace_current_label(new);
1442	} else {
1443		if (new) {
1444			aa_put_label(new);
1445			new = NULL;
1446		}
1447
1448		/* full transition will be built in exec path */
1449		error = aa_set_current_onexec(target, stack);
1450	}
 
1451
1452audit:
1453	error = fn_for_each_in_ns(label, profile,
1454			aa_audit_file(profile, &perms, op, request, auditname,
1455				      NULL, new ? new : target,
1456				      GLOBAL_ROOT_UID, info, error));
1457
1458out:
1459	aa_put_label(new);
1460	aa_put_label(target);
1461	aa_put_label(label);
1462
1463	return error;
1464}