Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1495 insertions, 0 deletions

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
new file mode 100644
index 0000000000..543105cf7e
--- /dev/null
+++ b/security/apparmor/domain.c
@@ -0,0 +1,1495 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor policy attachment and domain transitions
+ *
+ * Copyright (C) 2002-2008 Novell/SUSE
+ * Copyright 2009-2010 Canonical Ltd.
+ */
+
+#include <linux/errno.h>
+#include <linux/fdtable.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/syscalls.h>
+#include <linux/personality.h>
+#include <linux/xattr.h>
+#include <linux/user_namespace.h>
+
+#include "include/audit.h"
+#include "include/apparmorfs.h"
+#include "include/cred.h"
+#include "include/domain.h"
+#include "include/file.h"
+#include "include/ipc.h"
+#include "include/match.h"
+#include "include/path.h"
+#include "include/policy.h"
+#include "include/policy_ns.h"
+
+/**
+ * may_change_ptraced_domain - check if can change profile on ptraced task
+ * @cred: cred of task changing domain
+ * @to_label: profile to change to  (NOT NULL)
+ * @info: message if there is an error
+ *
+ * Check if current is ptraced and if so if the tracing task is allowed
+ * to trace the new domain
+ *
+ * Returns: %0 or error if change not allowed
+ */
+static int may_change_ptraced_domain(const struct cred *to_cred,
+				     struct aa_label *to_label,
+				     const char **info)
+{
+	struct task_struct *tracer;
+	struct aa_label *tracerl = NULL;
+	const struct cred *tracer_cred = NULL;
+
+	int error = 0;
+
+	rcu_read_lock();
+	tracer = ptrace_parent(current);
+	if (tracer) {
+		/* released below */
+		tracerl = aa_get_task_label(tracer);
+		tracer_cred = get_task_cred(tracer);
+	}
+	/* not ptraced */
+	if (!tracer || unconfined(tracerl))
+		goto out;
+
+	error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
+			      PTRACE_MODE_ATTACH);
+
+out:
+	rcu_read_unlock();
+	aa_put_label(tracerl);
+	put_cred(tracer_cred);
+
+	if (error)
+		*info = "ptrace prevents transition";
+	return error;
+}
+
+/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
+ * specifically this is an exact copy of aa_label_match except
+ * aa_compute_perms is replaced with aa_compute_fperms
+ * and policy.dfa with file.dfa
+ ****/
+/* match a profile and its associated ns component if needed
+ * Assumes visibility test has already been done.
+ * If a subns profile is not to be matched should be prescreened with
+ * visibility test.
+ */
+static inline aa_state_t match_component(struct aa_profile *profile,
+					 struct aa_profile *tp,
+					 bool stack, aa_state_t state)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	const char *ns_name;
+
+	if (stack)
+		state = aa_dfa_match(rules->file.dfa, state, "&");
+	if (profile->ns == tp->ns)
+		return aa_dfa_match(rules->file.dfa, state, tp->base.hname);
+
+	/* try matching with namespace name and then profile */
+	ns_name = aa_ns_name(profile->ns, tp->ns, true);
+	state = aa_dfa_match_len(rules->file.dfa, state, ":", 1);
+	state = aa_dfa_match(rules->file.dfa, state, ns_name);
+	state = aa_dfa_match_len(rules->file.dfa, state, ":", 1);
+	return aa_dfa_match(rules->file.dfa, state, tp->base.hname);
+}
+
+/**
+ * label_compound_match - find perms for full compound label
+ * @profile: profile to find perms for
+ * @label: label to check access permissions for
+ * @stack: whether this is a stacking request
+ * @state: state to start match in
+ * @subns: whether to do permission checks on components in a subns
+ * @request: permissions to request
+ * @perms: perms struct to set
+ *
+ * Returns: 0 on success else ERROR
+ *
+ * For the label A//&B//&C this does the perm match for A//&B//&C
+ * @perms should be preinitialized with allperms OR a previous permission
+ *        check to be stacked.
+ */
+static int label_compound_match(struct aa_profile *profile,
+				struct aa_label *label, bool stack,
+				aa_state_t state, bool subns, u32 request,
+				struct aa_perms *perms)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	struct aa_profile *tp;
+	struct label_it i;
+	struct path_cond cond = { };
+
+	/* find first subcomponent that is visible */
+	label_for_each(i, label, tp) {
+		if (!aa_ns_visible(profile->ns, tp->ns, subns))
+			continue;
+		state = match_component(profile, tp, stack, state);
+		if (!state)
+			goto fail;
+		goto next;
+	}
+
+	/* no component visible */
+	*perms = allperms;
+	return 0;
+
+next:
+	label_for_each_cont(i, label, tp) {
+		if (!aa_ns_visible(profile->ns, tp->ns, subns))
+			continue;
+		state = aa_dfa_match(rules->file.dfa, state, "//&");
+		state = match_component(profile, tp, false, state);
+		if (!state)
+			goto fail;
+	}
+	*perms = *(aa_lookup_fperms(&(rules->file), state, &cond));
+	aa_apply_modes_to_perms(profile, perms);
+	if ((perms->allow & request) != request)
+		return -EACCES;
+
+	return 0;
+
+fail:
+	*perms = nullperms;
+	return -EACCES;
+}
+
+/**
+ * label_components_match - find perms for all subcomponents of a label
+ * @profile: profile to find perms for
+ * @label: label to check access permissions for
+ * @stack: whether this is a stacking request
+ * @start: state to start match in
+ * @subns: whether to do permission checks on components in a subns
+ * @request: permissions to request
+ * @perms: an initialized perms struct to add accumulation to
+ *
+ * Returns: 0 on success else ERROR
+ *
+ * For the label A//&B//&C this does the perm match for each of A and B and C
+ * @perms should be preinitialized with allperms OR a previous permission
+ *        check to be stacked.
+ */
+static int label_components_match(struct aa_profile *profile,
+				  struct aa_label *label, bool stack,
+				  aa_state_t start, bool subns, u32 request,
+				  struct aa_perms *perms)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	struct aa_profile *tp;
+	struct label_it i;
+	struct aa_perms tmp;
+	struct path_cond cond = { };
+	aa_state_t state = 0;
+
+	/* find first subcomponent to test */
+	label_for_each(i, label, tp) {
+		if (!aa_ns_visible(profile->ns, tp->ns, subns))
+			continue;
+		state = match_component(profile, tp, stack, start);
+		if (!state)
+			goto fail;
+		goto next;
+	}
+
+	/* no subcomponents visible - no change in perms */
+	return 0;
+
+next:
+	tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
+	aa_apply_modes_to_perms(profile, &tmp);
+	aa_perms_accum(perms, &tmp);
+	label_for_each_cont(i, label, tp) {
+		if (!aa_ns_visible(profile->ns, tp->ns, subns))
+			continue;
+		state = match_component(profile, tp, stack, start);
+		if (!state)
+			goto fail;
+		tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
+		aa_apply_modes_to_perms(profile, &tmp);
+		aa_perms_accum(perms, &tmp);
+	}
+
+	if ((perms->allow & request) != request)
+		return -EACCES;
+
+	return 0;
+
+fail:
+	*perms = nullperms;
+	return -EACCES;
+}
+
+/**
+ * label_match - do a multi-component label match
+ * @profile: profile to match against (NOT NULL)
+ * @label: label to match (NOT NULL)
+ * @stack: whether this is a stacking request
+ * @state: state to start in
+ * @subns: whether to match subns components
+ * @request: permission request
+ * @perms: Returns computed perms (NOT NULL)
+ *
+ * Returns: the state the match finished in, may be the none matching state
+ */
+static int label_match(struct aa_profile *profile, struct aa_label *label,
+		       bool stack, aa_state_t state, bool subns, u32 request,
+		       struct aa_perms *perms)
+{
+	int error;
+
+	*perms = nullperms;
+	error = label_compound_match(profile, label, stack, state, subns,
+				     request, perms);
+	if (!error)
+		return error;
+
+	*perms = allperms;
+	return label_components_match(profile, label, stack, state, subns,
+				      request, perms);
+}
+
+/******* end TODO: dedup *****/
+
+/**
+ * change_profile_perms - find permissions for change_profile
+ * @profile: the current profile  (NOT NULL)
+ * @target: label to transition to (NOT NULL)
+ * @stack: whether this is a stacking request
+ * @request: requested perms
+ * @start: state to start matching in
+ *
+ *
+ * Returns: permission set
+ *
+ * currently only matches full label A//&B//&C or individual components A, B, C
+ * not arbitrary combinations. Eg. A//&B, C
+ */
+static int change_profile_perms(struct aa_profile *profile,
+				struct aa_label *target, bool stack,
+				u32 request, aa_state_t start,
+				struct aa_perms *perms)
+{
+	if (profile_unconfined(profile)) {
+		perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
+		perms->audit = perms->quiet = perms->kill = 0;
+		return 0;
+	}
+
+	/* TODO: add profile in ns screening */
+	return label_match(profile, target, stack, start, true, request, perms);
+}
+
+/**
+ * aa_xattrs_match - check whether a file matches the xattrs defined in profile
+ * @bprm: binprm struct for the process to validate
+ * @profile: profile to match against (NOT NULL)
+ * @state: state to start match in
+ *
+ * Returns: number of extended attributes that matched, or < 0 on error
+ */
+static int aa_xattrs_match(const struct linux_binprm *bprm,
+			   struct aa_profile *profile, aa_state_t state)
+{
+	int i;
+	struct dentry *d;
+	char *value = NULL;
+	struct aa_attachment *attach = &profile->attach;
+	int size, value_size = 0, ret = attach->xattr_count;
+
+	if (!bprm || !attach->xattr_count)
+		return 0;
+	might_sleep();
+
+	/* transition from exec match to xattr set */
+	state = aa_dfa_outofband_transition(attach->xmatch.dfa, state);
+	d = bprm->file->f_path.dentry;
+
+	for (i = 0; i < attach->xattr_count; i++) {
+		size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
+					  &value, value_size, GFP_KERNEL);
+		if (size >= 0) {
+			u32 index, perm;
+
+			/*
+			 * Check the xattr presence before value. This ensure
+			 * that not present xattr can be distinguished from a 0
+			 * length value or rule that matches any value
+			 */
+			state = aa_dfa_null_transition(attach->xmatch.dfa,
+						       state);
+			/* Check xattr value */
+			state = aa_dfa_match_len(attach->xmatch.dfa, state,
+						 value, size);
+			index = ACCEPT_TABLE(attach->xmatch.dfa)[state];
+			perm = attach->xmatch.perms[index].allow;
+			if (!(perm & MAY_EXEC)) {
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+		/* transition to next element */
+		state = aa_dfa_outofband_transition(attach->xmatch.dfa, state);
+		if (size < 0) {
+			/*
+			 * No xattr match, so verify if transition to
+			 * next element was valid. IFF so the xattr
+			 * was optional.
+			 */
+			if (!state) {
+				ret = -EINVAL;
+				goto out;
+			}
+			/* don't count missing optional xattr as matched */
+			ret--;
+		}
+	}
+
+out:
+	kfree(value);
+	return ret;
+}
+
+/**
+ * find_attach - do attachment search for unconfined processes
+ * @bprm - binprm structure of transitioning task
+ * @ns: the current namespace  (NOT NULL)
+ * @head - profile list to walk  (NOT NULL)
+ * @name - to match against  (NOT NULL)
+ * @info - info message if there was an error (NOT NULL)
+ *
+ * Do a linear search on the profiles in the list.  There is a matching
+ * preference where an exact match is preferred over a name which uses
+ * expressions to match, and matching expressions with the greatest
+ * xmatch_len are preferred.
+ *
+ * Requires: @head not be shared or have appropriate locks held
+ *
+ * Returns: label or NULL if no match found
+ */
+static struct aa_label *find_attach(const struct linux_binprm *bprm,
+				    struct aa_ns *ns, struct list_head *head,
+				    const char *name, const char **info)
+{
+	int candidate_len = 0, candidate_xattrs = 0;
+	bool conflict = false;
+	struct aa_profile *profile, *candidate = NULL;
+
+	AA_BUG(!name);
+	AA_BUG(!head);
+
+	rcu_read_lock();
+restart:
+	list_for_each_entry_rcu(profile, head, base.list) {
+		struct aa_attachment *attach = &profile->attach;
+
+		if (profile->label.flags & FLAG_NULL &&
+		    &profile->label == ns_unconfined(profile->ns))
+			continue;
+
+		/* Find the "best" matching profile. Profiles must
+		 * match the path and extended attributes (if any)
+		 * associated with the file. A more specific path
+		 * match will be preferred over a less specific one,
+		 * and a match with more matching extended attributes
+		 * will be preferred over one with fewer. If the best
+		 * match has both the same level of path specificity
+		 * and the same number of matching extended attributes
+		 * as another profile, signal a conflict and refuse to
+		 * match.
+		 */
+		if (attach->xmatch.dfa) {
+			unsigned int count;
+			aa_state_t state;
+			u32 index, perm;
+
+			state = aa_dfa_leftmatch(attach->xmatch.dfa,
+					attach->xmatch.start[AA_CLASS_XMATCH],
+					name, &count);
+			index = ACCEPT_TABLE(attach->xmatch.dfa)[state];
+			perm = attach->xmatch.perms[index].allow;
+			/* any accepting state means a valid match. */
+			if (perm & MAY_EXEC) {
+				int ret = 0;
+
+				if (count < candidate_len)
+					continue;
+
+				if (bprm && attach->xattr_count) {
+					long rev = READ_ONCE(ns->revision);
+
+					if (!aa_get_profile_not0(profile))
+						goto restart;
+					rcu_read_unlock();
+					ret = aa_xattrs_match(bprm, profile,
+							      state);
+					rcu_read_lock();
+					aa_put_profile(profile);
+					if (rev !=
+					    READ_ONCE(ns->revision))
+						/* policy changed */
+						goto restart;
+					/*
+					 * Fail matching if the xattrs don't
+					 * match
+					 */
+					if (ret < 0)
+						continue;
+				}
+				/*
+				 * TODO: allow for more flexible best match
+				 *
+				 * The new match isn't more specific
+				 * than the current best match
+				 */
+				if (count == candidate_len &&
+				    ret <= candidate_xattrs) {
+					/* Match is equivalent, so conflict */
+					if (ret == candidate_xattrs)
+						conflict = true;
+					continue;
+				}
+
+				/* Either the same length with more matching
+				 * xattrs, or a longer match
+				 */
+				candidate = profile;
+				candidate_len = max(count, attach->xmatch_len);
+				candidate_xattrs = ret;
+				conflict = false;
+			}
+		} else if (!strcmp(profile->base.name, name)) {
+			/*
+			 * old exact non-re match, without conditionals such
+			 * as xattrs. no more searching required
+			 */
+			candidate = profile;
+			goto out;
+		}
+	}
+
+	if (!candidate || conflict) {
+		if (conflict)
+			*info = "conflicting profile attachments";
+		rcu_read_unlock();
+		return NULL;
+	}
+
+out:
+	candidate = aa_get_newest_profile(candidate);
+	rcu_read_unlock();
+
+	return &candidate->label;
+}
+
+static const char *next_name(int xtype, const char *name)
+{
+	return NULL;
+}
+
+/**
+ * x_table_lookup - lookup an x transition name via transition table
+ * @profile: current profile (NOT NULL)
+ * @xindex: index into x transition table
+ * @name: returns: name tested to find label (NOT NULL)
+ *
+ * Returns: refcounted label, or NULL on failure (MAYBE NULL)
+ */
+struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
+				const char **name)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	struct aa_label *label = NULL;
+	u32 xtype = xindex & AA_X_TYPE_MASK;
+	int index = xindex & AA_X_INDEX_MASK;
+
+	AA_BUG(!name);
+
+	/* index is guaranteed to be in range, validated at load time */
+	/* TODO: move lookup parsing to unpack time so this is a straight
+	 *       index into the resultant label
+	 */
+	for (*name = rules->file.trans.table[index]; !label && *name;
+	     *name = next_name(xtype, *name)) {
+		if (xindex & AA_X_CHILD) {
+			struct aa_profile *new_profile;
+			/* release by caller */
+			new_profile = aa_find_child(profile, *name);
+			if (new_profile)
+				label = &new_profile->label;
+			continue;
+		}
+		label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
+				       true, false);
+		if (IS_ERR(label))
+			label = NULL;
+	}
+
+	/* released by caller */
+
+	return label;
+}
+
+/**
+ * x_to_label - get target label for a given xindex
+ * @profile: current profile  (NOT NULL)
+ * @bprm: binprm structure of transitioning task
+ * @name: name to lookup (NOT NULL)
+ * @xindex: index into x transition table
+ * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
+ *
+ * find label for a transition index
+ *
+ * Returns: refcounted label or NULL if not found available
+ */
+static struct aa_label *x_to_label(struct aa_profile *profile,
+				   const struct linux_binprm *bprm,
+				   const char *name, u32 xindex,
+				   const char **lookupname,
+				   const char **info)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	struct aa_label *new = NULL;
+	struct aa_ns *ns = profile->ns;
+	u32 xtype = xindex & AA_X_TYPE_MASK;
+	const char *stack = NULL;
+
+	switch (xtype) {
+	case AA_X_NONE:
+		/* fail exec unless ix || ux fallback - handled by caller */
+		*lookupname = NULL;
+		break;
+	case AA_X_TABLE:
+		/* TODO: fix when perm mapping done at unload */
+		stack = rules->file.trans.table[xindex & AA_X_INDEX_MASK];
+		if (*stack != '&') {
+			/* released by caller */
+			new = x_table_lookup(profile, xindex, lookupname);
+			stack = NULL;
+			break;
+		}
+		fallthrough;	/* to X_NAME */
+	case AA_X_NAME:
+		if (xindex & AA_X_CHILD)
+			/* released by caller */
+			new = find_attach(bprm, ns, &profile->base.profiles,
+					  name, info);
+		else
+			/* released by caller */
+			new = find_attach(bprm, ns, &ns->base.profiles,
+					  name, info);
+		*lookupname = name;
+		break;
+	}
+
+	if (!new) {
+		if (xindex & AA_X_INHERIT) {
+			/* (p|c|n)ix - don't change profile but do
+			 * use the newest version
+			 */
+			*info = "ix fallback";
+			/* no profile && no error */
+			new = aa_get_newest_label(&profile->label);
+		} else if (xindex & AA_X_UNCONFINED) {
+			new = aa_get_newest_label(ns_unconfined(profile->ns));
+			*info = "ux fallback";
+		}
+	}
+
+	if (new && stack) {
+		/* base the stack on post domain transition */
+		struct aa_label *base = new;
+
+		new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
+		if (IS_ERR(new))
+			new = NULL;
+		aa_put_label(base);
+	}
+
+	/* released by caller */
+	return new;
+}
+
+static struct aa_label *profile_transition(const struct cred *subj_cred,
+					   struct aa_profile *profile,
+					   const struct linux_binprm *bprm,
+					   char *buffer, struct path_cond *cond,
+					   bool *secure_exec)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	struct aa_label *new = NULL;
+	const char *info = NULL, *name = NULL, *target = NULL;
+	aa_state_t state = rules->file.start[AA_CLASS_FILE];
+	struct aa_perms perms = {};
+	bool nonewprivs = false;
+	int error = 0;
+
+	AA_BUG(!profile);
+	AA_BUG(!bprm);
+	AA_BUG(!buffer);
+
+	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
+			     &name, &info, profile->disconnected);
+	if (error) {
+		if (profile_unconfined(profile) ||
+		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
+			AA_DEBUG("name lookup ix on error");
+			error = 0;
+			new = aa_get_newest_label(&profile->label);
+		}
+		name = bprm->filename;
+		goto audit;
+	}
+
+	if (profile_unconfined(profile)) {
+		new = find_attach(bprm, profile->ns,
+				  &profile->ns->base.profiles, name, &info);
+		if (new) {
+			AA_DEBUG("unconfined attached to new label");
+			return new;
+		}
+		AA_DEBUG("unconfined exec no attachment");
+		return aa_get_newest_label(&profile->label);
+	}
+
+	/* find exec permissions for name */
+	state = aa_str_perms(&(rules->file), state, name, cond, &perms);
+	if (perms.allow & MAY_EXEC) {
+		/* exec permission determine how to transition */
+		new = x_to_label(profile, bprm, name, perms.xindex, &target,
+				 &info);
+		if (new && new->proxy == profile->label.proxy && info) {
+			/* hack ix fallback - improve how this is detected */
+			goto audit;
+		} else if (!new) {
+			error = -EACCES;
+			info = "profile transition not found";
+			/* remove MAY_EXEC to audit as failure */
+			perms.allow &= ~MAY_EXEC;
+		}
+	} else if (COMPLAIN_MODE(profile)) {
+		/* no exec permission - learning mode */
+		struct aa_profile *new_profile = NULL;
+
+		new_profile = aa_new_learning_profile(profile, false, name,
+						      GFP_KERNEL);
+		if (!new_profile) {
+			error = -ENOMEM;
+			info = "could not create null profile";
+		} else {
+			error = -EACCES;
+			new = &new_profile->label;
+		}
+		perms.xindex |= AA_X_UNSAFE;
+	} else
+		/* fail exec */
+		error = -EACCES;
+
+	if (!new)
+		goto audit;
+
+
+	if (!(perms.xindex & AA_X_UNSAFE)) {
+		if (DEBUG_ON) {
+			dbg_printk("apparmor: scrubbing environment variables"
+				   " for %s profile=", name);
+			aa_label_printk(new, GFP_KERNEL);
+			dbg_printk("\n");
+		}
+		*secure_exec = true;
+	}
+
+audit:
+	aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
+		      target, new,
+		      cond->uid, info, error);
+	if (!new || nonewprivs) {
+		aa_put_label(new);
+		return ERR_PTR(error);
+	}
+
+	return new;
+}
+
+static int profile_onexec(const struct cred *subj_cred,
+			  struct aa_profile *profile, struct aa_label *onexec,
+			  bool stack, const struct linux_binprm *bprm,
+			  char *buffer, struct path_cond *cond,
+			  bool *secure_exec)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	aa_state_t state = rules->file.start[AA_CLASS_FILE];
+	struct aa_perms perms = {};
+	const char *xname = NULL, *info = "change_profile onexec";
+	int error = -EACCES;
+
+	AA_BUG(!profile);
+	AA_BUG(!onexec);
+	AA_BUG(!bprm);
+	AA_BUG(!buffer);
+
+	if (profile_unconfined(profile)) {
+		/* change_profile on exec already granted */
+		/*
+		 * NOTE: Domain transitions from unconfined are allowed
+		 * even when no_new_privs is set because this aways results
+		 * in a further reduction of permissions.
+		 */
+		return 0;
+	}
+
+	error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
+			     &xname, &info, profile->disconnected);
+	if (error) {
+		if (profile_unconfined(profile) ||
+		    (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
+			AA_DEBUG("name lookup ix on error");
+			error = 0;
+		}
+		xname = bprm->filename;
+		goto audit;
+	}
+
+	/* find exec permissions for name */
+	state = aa_str_perms(&(rules->file), state, xname, cond, &perms);
+	if (!(perms.allow & AA_MAY_ONEXEC)) {
+		info = "no change_onexec valid for executable";
+		goto audit;
+	}
+	/* test if this exec can be paired with change_profile onexec.
+	 * onexec permission is linked to exec with a standard pairing
+	 * exec\0change_profile
+	 */
+	state = aa_dfa_null_transition(rules->file.dfa, state);
+	error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
+				     state, &perms);
+	if (error) {
+		perms.allow &= ~AA_MAY_ONEXEC;
+		goto audit;
+	}
+
+	if (!(perms.xindex & AA_X_UNSAFE)) {
+		if (DEBUG_ON) {
+			dbg_printk("apparmor: scrubbing environment "
+				   "variables for %s label=", xname);
+			aa_label_printk(onexec, GFP_KERNEL);
+			dbg_printk("\n");
+		}
+		*secure_exec = true;
+	}
+
+audit:
+	return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
+			     AA_MAY_ONEXEC, xname,
+			     NULL, onexec, cond->uid, info, error);
+}
+
+/* ensure none ns domain transitions are correctly applied with onexec */
+
+static struct aa_label *handle_onexec(const struct cred *subj_cred,
+				      struct aa_label *label,
+				      struct aa_label *onexec, bool stack,
+				      const struct linux_binprm *bprm,
+				      char *buffer, struct path_cond *cond,
+				      bool *unsafe)
+{
+	struct aa_profile *profile;
+	struct aa_label *new;
+	int error;
+
+	AA_BUG(!label);
+	AA_BUG(!onexec);
+	AA_BUG(!bprm);
+	AA_BUG(!buffer);
+
+	if (!stack) {
+		error = fn_for_each_in_ns(label, profile,
+				profile_onexec(subj_cred, profile, onexec, stack,
+					       bprm, buffer, cond, unsafe));
+		if (error)
+			return ERR_PTR(error);
+		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
+				aa_get_newest_label(onexec),
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
+						   cond, unsafe));
+
+	} else {
+		/* TODO: determine how much we want to loosen this */
+		error = fn_for_each_in_ns(label, profile,
+				profile_onexec(subj_cred, profile, onexec, stack, bprm,
+					       buffer, cond, unsafe));
+		if (error)
+			return ERR_PTR(error);
+		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
+				aa_label_merge(&profile->label, onexec,
+					       GFP_KERNEL),
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
+						   cond, unsafe));
+	}
+
+	if (new)
+		return new;
+
+	/* TODO: get rid of GLOBAL_ROOT_UID */
+	error = fn_for_each_in_ns(label, profile,
+			aa_audit_file(subj_cred, profile, &nullperms,
+				      OP_CHANGE_ONEXEC,
+				      AA_MAY_ONEXEC, bprm->filename, NULL,
+				      onexec, GLOBAL_ROOT_UID,
+				      "failed to build target label", -ENOMEM));
+	return ERR_PTR(error);
+}
+
+/**
+ * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
+ * @bprm: binprm for the exec  (NOT NULL)
+ *
+ * Returns: %0 or error on failure
+ *
+ * TODO: once the other paths are done see if we can't refactor into a fn
+ */
+int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
+{
+	struct aa_task_ctx *ctx;
+	struct aa_label *label, *new = NULL;
+	const struct cred *subj_cred;
+	struct aa_profile *profile;
+	char *buffer = NULL;
+	const char *info = NULL;
+	int error = 0;
+	bool unsafe = false;
+	vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
+					    file_inode(bprm->file));
+	struct path_cond cond = {
+		vfsuid_into_kuid(vfsuid),
+		file_inode(bprm->file)->i_mode
+	};
+
+	subj_cred = current_cred();
+	ctx = task_ctx(current);
+	AA_BUG(!cred_label(bprm->cred));
+	AA_BUG(!ctx);
+
+	label = aa_get_newest_label(cred_label(bprm->cred));
+
+	/*
+	 * Detect no new privs being set, and store the label it
+	 * occurred under. Ideally this would happen when nnp
+	 * is set but there isn't a good way to do that yet.
+	 *
+	 * Testing for unconfined must be done before the subset test
+	 */
+	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
+	    !ctx->nnp)
+		ctx->nnp = aa_get_label(label);
+
+	/* buffer freed below, name is pointer into buffer */
+	buffer = aa_get_buffer(false);
+	if (!buffer) {
+		error = -ENOMEM;
+		goto done;
+	}
+
+	/* Test for onexec first as onexec override other x transitions. */
+	if (ctx->onexec)
+		new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
+				    bprm, buffer, &cond, &unsafe);
+	else
+		new = fn_label_build(label, profile, GFP_KERNEL,
+				profile_transition(subj_cred, profile, bprm,
+						   buffer,
+						   &cond, &unsafe));
+
+	AA_BUG(!new);
+	if (IS_ERR(new)) {
+		error = PTR_ERR(new);
+		goto done;
+	} else if (!new) {
+		error = -ENOMEM;
+		goto done;
+	}
+
+	/* Policy has specified a domain transitions. If no_new_privs and
+	 * confined ensure the transition is to confinement that is subset
+	 * of the confinement when the task entered no new privs.
+	 *
+	 * NOTE: Domain transitions from unconfined and to stacked
+	 * subsets are allowed even when no_new_privs is set because this
+	 * aways results in a further reduction of permissions.
+	 */
+	if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
+	    !unconfined(label) &&
+	    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
+		error = -EPERM;
+		info = "no new privs";
+		goto audit;
+	}
+
+	if (bprm->unsafe & LSM_UNSAFE_SHARE) {
+		/* FIXME: currently don't mediate shared state */
+		;
+	}
+
+	if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
+		/* TODO: test needs to be profile of label to new */
+		error = may_change_ptraced_domain(bprm->cred, new, &info);
+		if (error)
+			goto audit;
+	}
+
+	if (unsafe) {
+		if (DEBUG_ON) {
+			dbg_printk("scrubbing environment variables for %s "
+				   "label=", bprm->filename);
+			aa_label_printk(new, GFP_KERNEL);
+			dbg_printk("\n");
+		}
+		bprm->secureexec = 1;
+	}
+
+	if (label->proxy != new->proxy) {
+		/* when transitioning clear unsafe personality bits */
+		if (DEBUG_ON) {
+			dbg_printk("apparmor: clearing unsafe personality "
+				   "bits. %s label=", bprm->filename);
+			aa_label_printk(new, GFP_KERNEL);
+			dbg_printk("\n");
+		}
+		bprm->per_clear |= PER_CLEAR_ON_SETID;
+	}
+	aa_put_label(cred_label(bprm->cred));
+	/* transfer reference, released when cred is freed */
+	set_cred_label(bprm->cred, new);
+
+done:
+	aa_put_label(label);
+	aa_put_buffer(buffer);
+
+	return error;
+
+audit:
+	error = fn_for_each(label, profile,
+			aa_audit_file(current_cred(), profile, &nullperms,
+				      OP_EXEC, MAY_EXEC,
+				      bprm->filename, NULL, new,
+				      vfsuid_into_kuid(vfsuid), info, error));
+	aa_put_label(new);
+	goto done;
+}
+
+/*
+ * Functions for self directed profile change
+ */
+
+
+/* helper fn for change_hat
+ *
+ * Returns: label for hat transition OR ERR_PTR.  Does NOT return NULL
+ */
+static struct aa_label *build_change_hat(const struct cred *subj_cred,
+					 struct aa_profile *profile,
+					 const char *name, bool sibling)
+{
+	struct aa_profile *root, *hat = NULL;
+	const char *info = NULL;
+	int error = 0;
+
+	if (sibling && PROFILE_IS_HAT(profile)) {
+		root = aa_get_profile_rcu(&profile->parent);
+	} else if (!sibling && !PROFILE_IS_HAT(profile)) {
+		root = aa_get_profile(profile);
+	} else {
+		info = "conflicting target types";
+		error = -EPERM;
+		goto audit;
+	}
+
+	hat = aa_find_child(root, name);
+	if (!hat) {
+		error = -ENOENT;
+		if (COMPLAIN_MODE(profile)) {
+			hat = aa_new_learning_profile(profile, true, name,
+						      GFP_KERNEL);
+			if (!hat) {
+				info = "failed null profile create";
+				error = -ENOMEM;
+			}
+		}
+	}
+	aa_put_profile(root);
+
+audit:
+	aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
+		      AA_MAY_CHANGEHAT,
+		      name, hat ? hat->base.hname : NULL,
+		      hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
+		      error);
+	if (!hat || (error && error != -ENOENT))
+		return ERR_PTR(error);
+	/* if hat && error - complain mode, already audited and we adjust for
+	 * complain mode allow by returning hat->label
+	 */
+	return &hat->label;
+}
+
+/* helper fn for changing into a hat
+ *
+ * Returns: label for hat transition or ERR_PTR. Does not return NULL
+ */
+static struct aa_label *change_hat(const struct cred *subj_cred,
+				   struct aa_label *label, const char *hats[],
+				   int count, int flags)
+{
+	struct aa_profile *profile, *root, *hat = NULL;
+	struct aa_label *new;
+	struct label_it it;
+	bool sibling = false;
+	const char *name, *info = NULL;
+	int i, error;
+
+	AA_BUG(!label);
+	AA_BUG(!hats);
+	AA_BUG(count < 1);
+
+	if (PROFILE_IS_HAT(labels_profile(label)))
+		sibling = true;
+
+	/*find first matching hat */
+	for (i = 0; i < count && !hat; i++) {
+		name = hats[i];
+		label_for_each_in_ns(it, labels_ns(label), label, profile) {
+			if (sibling && PROFILE_IS_HAT(profile)) {
+				root = aa_get_profile_rcu(&profile->parent);
+			} else if (!sibling && !PROFILE_IS_HAT(profile)) {
+				root = aa_get_profile(profile);
+			} else {	/* conflicting change type */
+				info = "conflicting targets types";
+				error = -EPERM;
+				goto fail;
+			}
+			hat = aa_find_child(root, name);
+			aa_put_profile(root);
+			if (!hat) {
+				if (!COMPLAIN_MODE(profile))
+					goto outer_continue;
+				/* complain mode succeed as if hat */
+			} else if (!PROFILE_IS_HAT(hat)) {
+				info = "target not hat";
+				error = -EPERM;
+				aa_put_profile(hat);
+				goto fail;
+			}
+			aa_put_profile(hat);
+		}
+		/* found a hat for all profiles in ns */
+		goto build;
+outer_continue:
+	;
+	}
+	/* no hats that match, find appropriate error
+	 *
+	 * In complain mode audit of the failure is based off of the first
+	 * hat supplied.  This is done due how userspace interacts with
+	 * change_hat.
+	 */
+	name = NULL;
+	label_for_each_in_ns(it, labels_ns(label), label, profile) {
+		if (!list_empty(&profile->base.profiles)) {
+			info = "hat not found";
+			error = -ENOENT;
+			goto fail;
+		}
+	}
+	info = "no hats defined";
+	error = -ECHILD;
+
+fail:
+	label_for_each_in_ns(it, labels_ns(label), label, profile) {
+		/*
+		 * no target as it has failed to be found or built
+		 *
+		 * change_hat uses probing and should not log failures
+		 * related to missing hats
+		 */
+		/* TODO: get rid of GLOBAL_ROOT_UID */
+		if (count > 1 || COMPLAIN_MODE(profile)) {
+			aa_audit_file(subj_cred, profile, &nullperms,
+				      OP_CHANGE_HAT,
+				      AA_MAY_CHANGEHAT, name, NULL, NULL,
+				      GLOBAL_ROOT_UID, info, error);
+		}
+	}
+	return ERR_PTR(error);
+
+build:
+	new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
+				   build_change_hat(subj_cred, profile, name,
+						    sibling),
+				   aa_get_label(&profile->label));
+	if (!new) {
+		info = "label build failed";
+		error = -ENOMEM;
+		goto fail;
+	} /* else if (IS_ERR) build_change_hat has logged error so return new */
+
+	return new;
+}
+
+/**
+ * aa_change_hat - change hat to/from subprofile
+ * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
+ * @count: number of hat names in @hats
+ * @token: magic value to validate the hat change
+ * @flags: flags affecting behavior of the change
+ *
+ * Returns %0 on success, error otherwise.
+ *
+ * Change to the first profile specified in @hats that exists, and store
+ * the @hat_magic in the current task context.  If the count == 0 and the
+ * @token matches that stored in the current task context, return to the
+ * top level profile.
+ *
+ * change_hat only applies to profiles in the current ns, and each profile
+ * in the ns must make the same transition otherwise change_hat will fail.
+ */
+int aa_change_hat(const char *hats[], int count, u64 token, int flags)
+{
+	const struct cred *subj_cred;
+	struct aa_task_ctx *ctx = task_ctx(current);
+	struct aa_label *label, *previous, *new = NULL, *target = NULL;
+	struct aa_profile *profile;
+	struct aa_perms perms = {};
+	const char *info = NULL;
+	int error = 0;
+
+	/* released below */
+	subj_cred = get_current_cred();
+	label = aa_get_newest_cred_label(subj_cred);
+	previous = aa_get_newest_label(ctx->previous);
+
+	/*
+	 * Detect no new privs being set, and store the label it
+	 * occurred under. Ideally this would happen when nnp
+	 * is set but there isn't a good way to do that yet.
+	 *
+	 * Testing for unconfined must be done before the subset test
+	 */
+	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
+		ctx->nnp = aa_get_label(label);
+
+	if (unconfined(label)) {
+		info = "unconfined can not change_hat";
+		error = -EPERM;
+		goto fail;
+	}
+
+	if (count) {
+		new = change_hat(subj_cred, label, hats, count, flags);
+		AA_BUG(!new);
+		if (IS_ERR(new)) {
+			error = PTR_ERR(new);
+			new = NULL;
+			/* already audited */
+			goto out;
+		}
+
+		/* target cred is the same as current except new label */
+		error = may_change_ptraced_domain(subj_cred, new, &info);
+		if (error)
+			goto fail;
+
+		/*
+		 * no new privs prevents domain transitions that would
+		 * reduce restrictions.
+		 */
+		if (task_no_new_privs(current) && !unconfined(label) &&
+		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
+			/* not an apparmor denial per se, so don't log it */
+			AA_DEBUG("no_new_privs - change_hat denied");
+			error = -EPERM;
+			goto out;
+		}
+
+		if (flags & AA_CHANGE_TEST)
+			goto out;
+
+		target = new;
+		error = aa_set_current_hat(new, token);
+		if (error == -EACCES)
+			/* kill task in case of brute force attacks */
+			goto kill;
+	} else if (previous && !(flags & AA_CHANGE_TEST)) {
+		/*
+		 * no new privs prevents domain transitions that would
+		 * reduce restrictions.
+		 */
+		if (task_no_new_privs(current) && !unconfined(label) &&
+		    !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
+			/* not an apparmor denial per se, so don't log it */
+			AA_DEBUG("no_new_privs - change_hat denied");
+			error = -EPERM;
+			goto out;
+		}
+
+		/* Return to saved label.  Kill task if restore fails
+		 * to avoid brute force attacks
+		 */
+		target = previous;
+		error = aa_restore_previous_label(token);
+		if (error) {
+			if (error == -EACCES)
+				goto kill;
+			goto fail;
+		}
+	} /* else ignore @flags && restores when there is no saved profile */
+
+out:
+	aa_put_label(new);
+	aa_put_label(previous);
+	aa_put_label(label);
+	put_cred(subj_cred);
+
+	return error;
+
+kill:
+	info = "failed token match";
+	perms.kill = AA_MAY_CHANGEHAT;
+
+fail:
+	fn_for_each_in_ns(label, profile,
+		aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
+			      AA_MAY_CHANGEHAT, NULL, NULL, target,
+			      GLOBAL_ROOT_UID, info, error));
+
+	goto out;
+}
+
+
+static int change_profile_perms_wrapper(const char *op, const char *name,
+					const struct cred *subj_cred,
+					struct aa_profile *profile,
+					struct aa_label *target, bool stack,
+					u32 request, struct aa_perms *perms)
+{
+	struct aa_ruleset *rules = list_first_entry(&profile->rules,
+						    typeof(*rules), list);
+	const char *info = NULL;
+	int error = 0;
+
+	if (!error)
+		error = change_profile_perms(profile, target, stack, request,
+					     rules->file.start[AA_CLASS_FILE],
+					     perms);
+	if (error)
+		error = aa_audit_file(subj_cred, profile, perms, op, request,
+				      name,
+				      NULL, target, GLOBAL_ROOT_UID, info,
+				      error);
+
+	return error;
+}
+
+/**
+ * aa_change_profile - perform a one-way profile transition
+ * @fqname: name of profile may include namespace (NOT NULL)
+ * @flags: flags affecting change behavior
+ *
+ * Change to new profile @name.  Unlike with hats, there is no way
+ * to change back.  If @name isn't specified the current profile name is
+ * used.
+ * If @onexec then the transition is delayed until
+ * the next exec.
+ *
+ * Returns %0 on success, error otherwise.
+ */
+int aa_change_profile(const char *fqname, int flags)
+{
+	struct aa_label *label, *new = NULL, *target = NULL;
+	struct aa_profile *profile;
+	struct aa_perms perms = {};
+	const char *info = NULL;
+	const char *auditname = fqname;		/* retain leading & if stack */
+	bool stack = flags & AA_CHANGE_STACK;
+	struct aa_task_ctx *ctx = task_ctx(current);
+	const struct cred *subj_cred = get_current_cred();
+	int error = 0;
+	char *op;
+	u32 request;
+
+	label = aa_get_current_label();
+
+	/*
+	 * Detect no new privs being set, and store the label it
+	 * occurred under. Ideally this would happen when nnp
+	 * is set but there isn't a good way to do that yet.
+	 *
+	 * Testing for unconfined must be done before the subset test
+	 */
+	if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
+		ctx->nnp = aa_get_label(label);
+
+	if (!fqname || !*fqname) {
+		aa_put_label(label);
+		AA_DEBUG("no profile name");
+		return -EINVAL;
+	}
+
+	if (flags & AA_CHANGE_ONEXEC) {
+		request = AA_MAY_ONEXEC;
+		if (stack)
+			op = OP_STACK_ONEXEC;
+		else
+			op = OP_CHANGE_ONEXEC;
+	} else {
+		request = AA_MAY_CHANGE_PROFILE;
+		if (stack)
+			op = OP_STACK;
+		else
+			op = OP_CHANGE_PROFILE;
+	}
+
+	if (*fqname == '&') {
+		stack = true;
+		/* don't have label_parse() do stacking */
+		fqname++;
+	}
+	target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
+	if (IS_ERR(target)) {
+		struct aa_profile *tprofile;
+
+		info = "label not found";
+		error = PTR_ERR(target);
+		target = NULL;
+		/*
+		 * TODO: fixme using labels_profile is not right - do profile
+		 * per complain profile
+		 */
+		if ((flags & AA_CHANGE_TEST) ||
+		    !COMPLAIN_MODE(labels_profile(label)))
+			goto audit;
+		/* released below */
+		tprofile = aa_new_learning_profile(labels_profile(label), false,
+						   fqname, GFP_KERNEL);
+		if (!tprofile) {
+			info = "failed null profile create";
+			error = -ENOMEM;
+			goto audit;
+		}
+		target = &tprofile->label;
+		goto check;
+	}
+
+	/*
+	 * self directed transitions only apply to current policy ns
+	 * TODO: currently requiring perms for stacking and straight change
+	 *       stacking doesn't strictly need this. Determine how much
+	 *       we want to loosen this restriction for stacking
+	 *
+	 * if (!stack) {
+	 */
+	error = fn_for_each_in_ns(label, profile,
+			change_profile_perms_wrapper(op, auditname,
+						     subj_cred,
+						     profile, target, stack,
+						     request, &perms));
+	if (error)
+		/* auditing done in change_profile_perms_wrapper */
+		goto out;
+
+	/* } */
+
+check:
+	/* check if tracing task is allowed to trace target domain */
+	error = may_change_ptraced_domain(subj_cred, target, &info);
+	if (error && !fn_for_each_in_ns(label, profile,
+					COMPLAIN_MODE(profile)))
+		goto audit;
+
+	/* TODO: add permission check to allow this
+	 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
+	 *      info = "not a single threaded task";
+	 *      error = -EACCES;
+	 *      goto audit;
+	 * }
+	 */
+	if (flags & AA_CHANGE_TEST)
+		goto out;
+
+	/* stacking is always a subset, so only check the nonstack case */
+	if (!stack) {
+		new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
+					   aa_get_label(target),
+					   aa_get_label(&profile->label));
+		/*
+		 * no new privs prevents domain transitions that would
+		 * reduce restrictions.
+		 */
+		if (task_no_new_privs(current) && !unconfined(label) &&
+		    !aa_label_is_unconfined_subset(new, ctx->nnp)) {
+			/* not an apparmor denial per se, so don't log it */
+			AA_DEBUG("no_new_privs - change_hat denied");
+			error = -EPERM;
+			goto out;
+		}
+	}
+
+	if (!(flags & AA_CHANGE_ONEXEC)) {
+		/* only transition profiles in the current ns */
+		if (stack)
+			new = aa_label_merge(label, target, GFP_KERNEL);
+		if (IS_ERR_OR_NULL(new)) {
+			info = "failed to build target label";
+			if (!new)
+				error = -ENOMEM;
+			else
+				error = PTR_ERR(new);
+			new = NULL;
+			perms.allow = 0;
+			goto audit;
+		}
+		error = aa_replace_current_label(new);
+	} else {
+		if (new) {
+			aa_put_label(new);
+			new = NULL;
+		}
+
+		/* full transition will be built in exec path */
+		error = aa_set_current_onexec(target, stack);
+	}
+
+audit:
+	error = fn_for_each_in_ns(label, profile,
+			aa_audit_file(subj_cred,
+				      profile, &perms, op, request, auditname,
+				      NULL, new ? new : target,
+				      GLOBAL_ROOT_UID, info, error));
+
+out:
+	aa_put_label(new);
+	aa_put_label(target);
+	aa_put_label(label);
+	put_cred(subj_cred);
+
+	return error;
+}