apparmor: refcount the pdb

With the move to permission tables the dfa is no longer a stand
alone entity when used, needing a minimum of a permission table.
However it still could be shared among different pdbs each using
a different permission table.

Instead of duping the permission table when sharing a pdb, add a
refcount to the pdb so it can be easily shared.
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/apparmorfs.c

@@ -619,23 +619,23 @@ static void profile_query_cb(struct aa_profile *profile, struct aa_perms *perms,
 
 	if (profile_unconfined(profile))
 		return;
-	if (rules->file.dfa && *match_str == AA_CLASS_FILE) {
-		state = aa_dfa_match_len(rules->file.dfa,
-					 rules->file.start[AA_CLASS_FILE],
+	if (rules->file->dfa && *match_str == AA_CLASS_FILE) {
+		state = aa_dfa_match_len(rules->file->dfa,
+					 rules->file->start[AA_CLASS_FILE],
 					 match_str + 1, match_len - 1);
 		if (state) {
 			struct path_cond cond = { };
 
-			tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
+			tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 		}
-	} else if (rules->policy.dfa) {
+	} else if (rules->policy->dfa) {
 		if (!RULE_MEDIATES(rules, *match_str))
 			return;	/* no change to current perms */
-		state = aa_dfa_match_len(rules->policy.dfa,
-					 rules->policy.start[0],
+		state = aa_dfa_match_len(rules->policy->dfa,
+					 rules->policy->start[0],
 					 match_str, match_len);
 		if (state)
-			tmp = *aa_lookup_perms(&rules->policy, state);
+			tmp = *aa_lookup_perms(rules->policy, state);
 	}
 	aa_apply_modes_to_perms(profile, &tmp);
 	aa_perms_accum_raw(perms, &tmp);
@@ -1096,7 +1096,7 @@ static int seq_profile_attach_show(struct seq_file *seq, void *v)
 	struct aa_profile *profile = labels_profile(label);
 	if (profile->attach.xmatch_str)
 		seq_printf(seq, "%s\n", profile->attach.xmatch_str);
-	else if (profile->attach.xmatch.dfa)
+	else if (profile->attach.xmatch->dfa)
 		seq_puts(seq, "<unknown>\n");
 	else
 		seq_printf(seq, "%s\n", profile->base.name);

security/apparmor/domain.c

@@ -77,7 +77,7 @@ static int may_change_ptraced_domain(const struct cred *to_cred,
 /**** 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
+ * and policy->dfa with file->dfa
  ****/
 /* match a profile and its associated ns component if needed
  * Assumes visibility test has already been done.
@@ -93,16 +93,16 @@ static inline aa_state_t match_component(struct aa_profile *profile,
 	const char *ns_name;
 
 	if (stack)
-		state = aa_dfa_match(rules->file.dfa, state, "&");
+		state = aa_dfa_match(rules->file->dfa, state, "&");
 	if (profile->ns == tp->ns)
-		return aa_dfa_match(rules->file.dfa, state, tp->base.hname);
+		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);
+	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);
 }
 
 /**
@@ -150,12 +150,12 @@ static int label_compound_match(struct aa_profile *profile,
 	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 = 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));
+	*perms = *(aa_lookup_fperms(rules->file, state, &cond));
 	aa_apply_modes_to_perms(profile, perms);
 	if ((perms->allow & request) != request)
 		return -EACCES;
@@ -210,7 +210,7 @@ static int label_components_match(struct aa_profile *profile,
 	return 0;
 
 next:
-	tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
+	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) {
@@ -219,7 +219,7 @@ static int label_components_match(struct aa_profile *profile,
 		state = match_component(profile, tp, stack, start);
 		if (!state)
 			goto fail;
-		tmp = *(aa_lookup_fperms(&(rules->file), state, &cond));
+		tmp = *(aa_lookup_fperms(rules->file, state, &cond));
 		aa_apply_modes_to_perms(profile, &tmp);
 		aa_perms_accum(perms, &tmp);
 	}
@@ -317,7 +317,7 @@ static int aa_xattrs_match(const struct linux_binprm *bprm,
 	might_sleep();
 
 	/* transition from exec match to xattr set */
-	state = aa_dfa_outofband_transition(attach->xmatch.dfa, state);
+	state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
 	d = bprm->file->f_path.dentry;
 
 	for (i = 0; i < attach->xattr_count; i++) {
@@ -331,20 +331,20 @@ static int aa_xattrs_match(const struct linux_binprm *bprm,
 			 * 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 = aa_dfa_null_transition(attach->xmatch->dfa,
 						       state);
 			/* Check xattr value */
-			state = aa_dfa_match_len(attach->xmatch.dfa, state,
+			state = aa_dfa_match_len(attach->xmatch->dfa, state,
 						 value, size);
-			index = ACCEPT_TABLE(attach->xmatch.dfa)[state];
-			perm = attach->xmatch.perms[index].allow;
+			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);
+		state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
 		if (size < 0) {
 			/*
 			 * No xattr match, so verify if transition to
@@ -413,16 +413,16 @@ static struct aa_label *find_attach(const struct linux_binprm *bprm,
 		 * as another profile, signal a conflict and refuse to
 		 * match.
 		 */
-		if (attach->xmatch.dfa) {
+		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],
+			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;
+			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;
@@ -525,7 +525,7 @@ struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
 	/* 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;
+	for (*name = rules->file->trans.table[index]; !label && *name;
 	     *name = next_name(xtype, *name)) {
 		if (xindex & AA_X_CHILD) {
 			struct aa_profile *new_profile;
@@ -579,7 +579,7 @@ static struct aa_label *x_to_label(struct aa_profile *profile,
 		break;
 	case AA_X_TABLE:
 		/* TODO: fix when perm mapping done at unload */
-		stack = rules->file.trans.table[xindex & AA_X_INDEX_MASK];
+		stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
 		if (*stack != '&') {
 			/* released by caller */
 			new = x_table_lookup(profile, xindex, lookupname);
@@ -638,7 +638,7 @@ static struct aa_label *profile_transition(const struct cred *subj_cred,
 						    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];
+	aa_state_t state = rules->file->start[AA_CLASS_FILE];
 	struct aa_perms perms = {};
 	bool nonewprivs = false;
 	int error = 0;
@@ -672,7 +672,7 @@ static struct aa_label *profile_transition(const struct cred *subj_cred,
 	}
 
 	/* find exec permissions for name */
-	state = aa_str_perms(&(rules->file), state, name, cond, &perms);
+	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,
@@ -738,7 +738,7 @@ static int profile_onexec(const struct cred *subj_cred,
 {
 	struct aa_ruleset *rules = list_first_entry(&profile->rules,
 						    typeof(*rules), list);
-	aa_state_t state = rules->file.start[AA_CLASS_FILE];
+	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;
@@ -771,7 +771,7 @@ static int profile_onexec(const struct cred *subj_cred,
 	}
 
 	/* find exec permissions for name */
-	state = aa_str_perms(&(rules->file), state, xname, cond, &perms);
+	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;
@@ -780,7 +780,7 @@ static int profile_onexec(const struct cred *subj_cred,
 	 * onexec permission is linked to exec with a standard pairing
 	 * exec\0change_profile
 	 */
-	state = aa_dfa_null_transition(rules->file.dfa, state);
+	state = aa_dfa_null_transition(rules->file->dfa, state);
 	error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
 				     state, &perms);
 	if (error) {
@@ -1300,7 +1300,7 @@ static int change_profile_perms_wrapper(const char *op, const char *name,
 
 	if (!error)
 		error = change_profile_perms(profile, target, stack, request,
-					     rules->file.start[AA_CLASS_FILE],
+					     rules->file->start[AA_CLASS_FILE],
 					     perms);
 	if (error)
 		error = aa_audit_file(subj_cred, profile, perms, op, request,

security/apparmor/file.c

@@ -236,7 +236,7 @@ static int __aa_path_perm(const char *op, const struct cred *subj_cred,
 
 	if (profile_unconfined(profile))
 		return 0;
-	aa_str_perms(&(rules->file), rules->file.start[AA_CLASS_FILE],
+	aa_str_perms(rules->file, rules->file->start[AA_CLASS_FILE],
 		     name, cond, perms);
 	if (request & ~perms->allow)
 		e = -EACCES;
@@ -353,16 +353,16 @@ static int profile_path_link(const struct cred *subj_cred,
 
 	error = -EACCES;
 	/* aa_str_perms - handles the case of the dfa being NULL */
-	state = aa_str_perms(&(rules->file),
-			     rules->file.start[AA_CLASS_FILE], lname,
+	state = aa_str_perms(rules->file,
+			     rules->file->start[AA_CLASS_FILE], lname,
 			     cond, &lperms);
 
 	if (!(lperms.allow & AA_MAY_LINK))
 		goto audit;
 
 	/* test to see if target can be paired with link */
-	state = aa_dfa_null_transition(rules->file.dfa, state);
-	aa_str_perms(&(rules->file), state, tname, cond, &perms);
+	state = aa_dfa_null_transition(rules->file->dfa, state);
+	aa_str_perms(rules->file, state, tname, cond, &perms);
 
 	/* force audit/quiet masks for link are stored in the second entry
 	 * in the link pair.
@@ -384,7 +384,7 @@ static int profile_path_link(const struct cred *subj_cred,
 	/* Do link perm subset test requiring allowed permission on link are
 	 * a subset of the allowed permissions on target.
 	 */
-	aa_str_perms(&(rules->file), rules->file.start[AA_CLASS_FILE],
+	aa_str_perms(rules->file, rules->file->start[AA_CLASS_FILE],
 		     tname, cond, &perms);
 
 	/* AA_MAY_LINK is not considered in the subset test */

security/apparmor/include/lib.h

@@ -16,6 +16,8 @@
 
 #include "match.h"
 
+extern struct aa_dfa *stacksplitdfa;
+
 /*
  * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
  * which is not related to profile accesses.

security/apparmor/include/match.h

@@ -102,9 +102,6 @@ struct aa_dfa {
 	struct table_header *tables[YYTD_ID_TSIZE];
 };
 
-extern struct aa_dfa *nulldfa;
-extern struct aa_dfa *stacksplitdfa;
-
 #define byte_to_byte(X) (X)
 
 #define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX)	\
@@ -122,9 +119,6 @@ static inline size_t table_size(size_t len, size_t el_size)
 	return ALIGN(sizeof(struct table_header) + len * el_size, 8);
 }
 
-int aa_setup_dfa_engine(void);
-void aa_teardown_dfa_engine(void);
-
 #define aa_state_t unsigned int
 
 struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);

security/apparmor/include/policy.h

@@ -74,12 +74,14 @@ enum profile_mode {
 
 
 /* struct aa_policydb - match engine for a policy
+ * count: refcount for the pdb
  * dfa: dfa pattern match
  * perms: table of permissions
  * strs: table of strings, index by x
  * start: set of start states for the different classes of data
  */
 struct aa_policydb {
+	struct kref count;
 	struct aa_dfa *dfa;
 	struct {
 		struct aa_perms *perms;
@@ -89,13 +91,36 @@ struct aa_policydb {
 	aa_state_t start[AA_CLASS_LAST + 1];
 };
 
-static inline void aa_destroy_policydb(struct aa_policydb *policy)
+extern struct aa_policydb *nullpdb;
+
+struct aa_policydb *aa_alloc_pdb(gfp_t gfp);
+void aa_pdb_free_kref(struct kref *kref);
+
+/**
+ * aa_get_pdb - increment refcount on @pdb
+ * @pdb: policydb  (MAYBE NULL)
+ *
+ * Returns: pointer to @pdb if @pdb is NULL will return NULL
+ * Requires: @pdb must be held with valid refcount when called
+ */
+static inline struct aa_policydb *aa_get_pdb(struct aa_policydb *pdb)
 {
-	aa_put_dfa(policy->dfa);
-	if (policy->perms)
-		kvfree(policy->perms);
-	aa_free_str_table(&policy->trans);
+	if (pdb)
+		kref_get(&(pdb->count));
 
+	return pdb;
+}
+
+/**
+ * aa_put_pdb - put a pdb refcount
+ * @pdb: pdb to put refcount   (MAYBE NULL)
+ *
+ * Requires: if @pdb != NULL that a valid refcount be held
+ */
+static inline void aa_put_pdb(struct aa_policydb *pdb)
+{
+	if (pdb)
+		kref_put(&pdb->count, aa_pdb_free_kref);
 }
 
 static inline struct aa_perms *aa_lookup_perms(struct aa_policydb *policy,
@@ -139,8 +164,8 @@ struct aa_ruleset {
 	int size;
 
 	/* TODO: merge policy and file */
-	struct aa_policydb policy;
-	struct aa_policydb file;
+	struct aa_policydb *policy;
+	struct aa_policydb *file;
 	struct aa_caps caps;
 
 	struct aa_rlimit rlimits;
@@ -159,7 +184,7 @@ struct aa_ruleset {
  */
 struct aa_attachment {
 	const char *xmatch_str;
-	struct aa_policydb xmatch;
+	struct aa_policydb *xmatch;
 	unsigned int xmatch_len;
 	int xattr_count;
 	char **xattrs;
@@ -267,10 +292,10 @@ static inline aa_state_t RULE_MEDIATES(struct aa_ruleset *rules,
 				       unsigned char class)
 {
 	if (class <= AA_CLASS_LAST)
-		return rules->policy.start[class];
+		return rules->policy->start[class];
 	else
-		return aa_dfa_match_len(rules->policy.dfa,
-					rules->policy.start[0], &class, 1);
+		return aa_dfa_match_len(rules->policy->dfa,
+					rules->policy->start[0], &class, 1);
 }
 
 static inline aa_state_t RULE_MEDIATES_AF(struct aa_ruleset *rules, u16 AF)
@@ -280,7 +305,7 @@ static inline aa_state_t RULE_MEDIATES_AF(struct aa_ruleset *rules, u16 AF)
 
 	if (!state)
 		return DFA_NOMATCH;
-	return aa_dfa_match_len(rules->policy.dfa, state, (char *) &be_af, 2);
+	return aa_dfa_match_len(rules->policy->dfa, state, (char *) &be_af, 2);
 }
 
 static inline aa_state_t ANY_RULE_MEDIATES(struct list_head *head,

security/apparmor/ipc.c

@@ -92,8 +92,8 @@ static int profile_signal_perm(const struct cred *cred,
 	ad->subj_cred = cred;
 	ad->peer = peer;
 	/* TODO: secondary cache check <profile, profile, perm> */
-	state = aa_dfa_next(rules->policy.dfa,
-			    rules->policy.start[AA_CLASS_SIGNAL],
+	state = aa_dfa_next(rules->policy->dfa,
+			    rules->policy->start[AA_CLASS_SIGNAL],
 			    ad->signal);
 	aa_label_match(profile, rules, peer, state, false, request, &perms);
 	aa_apply_modes_to_perms(profile, &perms);

security/apparmor/label.c

@@ -1270,14 +1270,14 @@ static inline aa_state_t match_component(struct aa_profile *profile,
 	const char *ns_name;
 
 	if (profile->ns == tp->ns)
-		return aa_dfa_match(rules->policy.dfa, state, tp->base.hname);
+		return aa_dfa_match(rules->policy->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->policy.dfa, state, ":", 1);
-	state = aa_dfa_match(rules->policy.dfa, state, ns_name);
-	state = aa_dfa_match_len(rules->policy.dfa, state, ":", 1);
-	return aa_dfa_match(rules->policy.dfa, state, tp->base.hname);
+	state = aa_dfa_match_len(rules->policy->dfa, state, ":", 1);
+	state = aa_dfa_match(rules->policy->dfa, state, ns_name);
+	state = aa_dfa_match_len(rules->policy->dfa, state, ":", 1);
+	return aa_dfa_match(rules->policy->dfa, state, tp->base.hname);
 }
 
 /**
@@ -1323,12 +1323,12 @@ static int label_compound_match(struct aa_profile *profile,
 	label_for_each_cont(i, label, tp) {
 		if (!aa_ns_visible(profile->ns, tp->ns, subns))
 			continue;
-		state = aa_dfa_match(rules->policy.dfa, state, "//&");
+		state = aa_dfa_match(rules->policy->dfa, state, "//&");
 		state = match_component(profile, rules, tp, state);
 		if (!state)
 			goto fail;
 	}
-	*perms = *aa_lookup_perms(&rules->policy, state);
+	*perms = *aa_lookup_perms(rules->policy, state);
 	aa_apply_modes_to_perms(profile, perms);
 	if ((perms->allow & request) != request)
 		return -EACCES;
@@ -1381,7 +1381,7 @@ static int label_components_match(struct aa_profile *profile,
 	return 0;
 
 next:
-	tmp = *aa_lookup_perms(&rules->policy, state);
+	tmp = *aa_lookup_perms(rules->policy, state);
 	aa_apply_modes_to_perms(profile, &tmp);
 	aa_perms_accum(perms, &tmp);
 	label_for_each_cont(i, label, tp) {
@@ -1390,7 +1390,7 @@ static int label_components_match(struct aa_profile *profile,
 		state = match_component(profile, rules, tp, start);
 		if (!state)
 			goto fail;
-		tmp = *aa_lookup_perms(&rules->policy, state);
+		tmp = *aa_lookup_perms(rules->policy, state);
 		aa_apply_modes_to_perms(profile, &tmp);
 		aa_perms_accum(perms, &tmp);
 	}

security/apparmor/lib.c

@@ -341,8 +341,8 @@ void aa_profile_match_label(struct aa_profile *profile,
 	/* TODO: doesn't yet handle extended types */
 	aa_state_t state;
 
-	state = aa_dfa_next(rules->policy.dfa,
-			    rules->policy.start[AA_CLASS_LABEL],
+	state = aa_dfa_next(rules->policy->dfa,
+			    rules->policy->start[AA_CLASS_LABEL],
 			    type);
 	aa_label_match(profile, rules, label, state, false, request, perms);
 }

security/apparmor/lsm.c

@@ -1887,6 +1887,69 @@ static int __init apparmor_nf_ip_init(void)
 __initcall(apparmor_nf_ip_init);
 #endif
 
+static char nulldfa_src[] = {
+	#include "nulldfa.in"
+};
+struct aa_dfa *nulldfa;
+
+static char stacksplitdfa_src[] = {
+	#include "stacksplitdfa.in"
+};
+struct aa_dfa *stacksplitdfa;
+struct aa_policydb *nullpdb;
+
+static int __init aa_setup_dfa_engine(void)
+{
+	int error = -ENOMEM;
+
+	nullpdb = aa_alloc_pdb(GFP_KERNEL);
+	if (!nullpdb)
+		return -ENOMEM;
+
+	nulldfa = aa_dfa_unpack(nulldfa_src, sizeof(nulldfa_src),
+			    TO_ACCEPT1_FLAG(YYTD_DATA32) |
+			    TO_ACCEPT2_FLAG(YYTD_DATA32));
+	if (IS_ERR(nulldfa)) {
+		error = PTR_ERR(nulldfa);
+		goto fail;
+	}
+	nullpdb->dfa = aa_get_dfa(nulldfa);
+	nullpdb->perms = kcalloc(2, sizeof(struct aa_perms), GFP_KERNEL);
+	if (!nullpdb->perms)
+		goto fail;
+	nullpdb->size = 2;
+
+	stacksplitdfa = aa_dfa_unpack(stacksplitdfa_src,
+				      sizeof(stacksplitdfa_src),
+				      TO_ACCEPT1_FLAG(YYTD_DATA32) |
+				      TO_ACCEPT2_FLAG(YYTD_DATA32));
+	if (IS_ERR(stacksplitdfa)) {
+		error = PTR_ERR(stacksplitdfa);
+		goto fail;
+	}
+
+	return 0;
+
+fail:
+	aa_put_pdb(nullpdb);
+	aa_put_dfa(nulldfa);
+	nullpdb = NULL;
+	nulldfa = NULL;
+	stacksplitdfa = NULL;
+
+	return error;
+}
+
+static void __init aa_teardown_dfa_engine(void)
+{
+	aa_put_dfa(stacksplitdfa);
+	aa_put_dfa(nulldfa);
+	aa_put_pdb(nullpdb);
+	nullpdb = NULL;
+	stacksplitdfa = NULL;
+	nulldfa = NULL;
+}
+
 static int __init apparmor_init(void)
 {
 	int error;

security/apparmor/match.c

@@ -21,50 +21,6 @@
 
 #define base_idx(X) ((X) & 0xffffff)
 
-static char nulldfa_src[] = {
-	#include "nulldfa.in"
-};
-struct aa_dfa *nulldfa;
-
-static char stacksplitdfa_src[] = {
-	#include "stacksplitdfa.in"
-};
-struct aa_dfa *stacksplitdfa;
-
-int __init aa_setup_dfa_engine(void)
-{
-	int error;
-
-	nulldfa = aa_dfa_unpack(nulldfa_src, sizeof(nulldfa_src),
-				TO_ACCEPT1_FLAG(YYTD_DATA32) |
-				TO_ACCEPT2_FLAG(YYTD_DATA32));
-	if (IS_ERR(nulldfa)) {
-		error = PTR_ERR(nulldfa);
-		nulldfa = NULL;
-		return error;
-	}
-
-	stacksplitdfa = aa_dfa_unpack(stacksplitdfa_src,
-				      sizeof(stacksplitdfa_src),
-				      TO_ACCEPT1_FLAG(YYTD_DATA32) |
-				      TO_ACCEPT2_FLAG(YYTD_DATA32));
-	if (IS_ERR(stacksplitdfa)) {
-		aa_put_dfa(nulldfa);
-		nulldfa = NULL;
-		error = PTR_ERR(stacksplitdfa);
-		stacksplitdfa = NULL;
-		return error;
-	}
-
-	return 0;
-}
-
-void __init aa_teardown_dfa_engine(void)
-{
-	aa_put_dfa(stacksplitdfa);
-	aa_put_dfa(nulldfa);
-}
-
 /**
  * unpack_table - unpack a dfa table (one of accept, default, base, next check)
  * @blob: data to unpack (NOT NULL)

security/apparmor/mount.c

@@ -332,8 +332,8 @@ static int match_mnt_path_str(const struct cred *subj_cred,
 	}
 
 	error = -EACCES;
-	pos = do_match_mnt(&rules->policy,
-			   rules->policy.start[AA_CLASS_MOUNT],
+	pos = do_match_mnt(rules->policy,
+			   rules->policy->start[AA_CLASS_MOUNT],
 			   mntpnt, devname, type, flags, data, binary, &perms);
 	if (pos) {
 		info = mnt_info_table[pos];
@@ -606,10 +606,10 @@ static int profile_umount(const struct cred *subj_cred,
 	if (error)
 		goto audit;
 
-	state = aa_dfa_match(rules->policy.dfa,
-			     rules->policy.start[AA_CLASS_MOUNT],
+	state = aa_dfa_match(rules->policy->dfa,
+			     rules->policy->start[AA_CLASS_MOUNT],
 			     name);
-	perms = *aa_lookup_perms(&rules->policy, state);
+	perms = *aa_lookup_perms(rules->policy, state);
 	if (AA_MAY_UMOUNT & ~perms.allow)
 		error = -EACCES;
 
@@ -680,12 +680,12 @@ static struct aa_label *build_pivotroot(const struct cred *subj_cred,
 		goto audit;
 
 	error = -EACCES;
-	state = aa_dfa_match(rules->policy.dfa,
-			     rules->policy.start[AA_CLASS_MOUNT],
+	state = aa_dfa_match(rules->policy->dfa,
+			     rules->policy->start[AA_CLASS_MOUNT],
 			     new_name);
-	state = aa_dfa_null_transition(rules->policy.dfa, state);
-	state = aa_dfa_match(rules->policy.dfa, state, old_name);
-	perms = *aa_lookup_perms(&rules->policy, state);
+	state = aa_dfa_null_transition(rules->policy->dfa, state);
+	state = aa_dfa_match(rules->policy->dfa, state, old_name);
+	perms = *aa_lookup_perms(rules->policy, state);
 
 	if (AA_MAY_PIVOTROOT & perms.allow)
 		error = 0;

security/apparmor/net.c

@@ -127,9 +127,9 @@ int aa_profile_af_perm(struct aa_profile *profile,
 
 	buffer[0] = cpu_to_be16(family);
 	buffer[1] = cpu_to_be16((u16) type);
-	state = aa_dfa_match_len(rules->policy.dfa, state, (char *) &buffer,
+	state = aa_dfa_match_len(rules->policy->dfa, state, (char *) &buffer,
 				 4);
-	perms = *aa_lookup_perms(&rules->policy, state);
+	perms = *aa_lookup_perms(rules->policy, state);
 	aa_apply_modes_to_perms(profile, &perms);
 
 	return aa_check_perms(profile, &perms, request, ad, audit_net_cb);

security/apparmor/policy.c

@@ -98,6 +98,41 @@ const char *const aa_profile_mode_names[] = {
 };
 
 
+static void aa_free_pdb(struct aa_policydb *policy)
+{
+	if (policy) {
+		aa_put_dfa(policy->dfa);
+		if (policy->perms)
+			kvfree(policy->perms);
+		aa_free_str_table(&policy->trans);
+	}
+}
+
+/**
+ * aa_pdb_free_kref - free aa_policydb by kref (called by aa_put_pdb)
+ * @kr: kref callback for freeing of a dfa  (NOT NULL)
+ */
+void aa_pdb_free_kref(struct kref *kref)
+{
+	struct aa_policydb *pdb = container_of(kref, struct aa_policydb, count);
+
+	aa_free_pdb(pdb);
+}
+
+
+struct aa_policydb *aa_alloc_pdb(gfp_t gfp)
+{
+	struct aa_policydb *pdb = kzalloc(sizeof(struct aa_policydb), gfp);
+
+	if (!pdb)
+		return NULL;
+
+	kref_init(&pdb->count);
+
+	return pdb;
+}
+
+
 /**
  * __add_profile - add a profiles to list and label tree
  * @list: list to add it to  (NOT NULL)
@@ -200,15 +235,15 @@ static void free_attachment(struct aa_attachment *attach)
 	for (i = 0; i < attach->xattr_count; i++)
 		kfree_sensitive(attach->xattrs[i]);
 	kfree_sensitive(attach->xattrs);
-	aa_destroy_policydb(&attach->xmatch);
+	aa_put_pdb(attach->xmatch);
 }
 
 static void free_ruleset(struct aa_ruleset *rules)
 {
 	int i;
 
-	aa_destroy_policydb(&rules->file);
-	aa_destroy_policydb(&rules->policy);
+	aa_put_pdb(rules->file);
+	aa_put_pdb(rules->policy);
 	aa_free_cap_rules(&rules->caps);
 	aa_free_rlimit_rules(&rules->rlimits);
 
@@ -590,16 +625,8 @@ struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name,
 	/* TODO: ideally we should inherit abi from parent */
 	profile->label.flags |= FLAG_NULL;
 	rules = list_first_entry(&profile->rules, typeof(*rules), list);
-	rules->file.dfa = aa_get_dfa(nulldfa);
-	rules->file.perms = kcalloc(2, sizeof(struct aa_perms), gfp);
-	if (!rules->file.perms)
-		goto fail;
-	rules->file.size = 2;
-	rules->policy.dfa = aa_get_dfa(nulldfa);
-	rules->policy.perms = kcalloc(2, sizeof(struct aa_perms), gfp);
-	if (!rules->policy.perms)
-		goto fail;
-	rules->policy.size = 2;
+	rules->file = aa_get_pdb(nullpdb);
+	rules->policy = aa_get_pdb(nullpdb);
 
 	if (parent) {
 		profile->path_flags = parent->path_flags;
@@ -610,11 +637,6 @@ struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name,
 	}
 
 	return profile;
-
-fail:
-	aa_free_profile(profile);
-
-	return NULL;
 }
 
 /**

security/apparmor/policy_unpack.c

@@ -703,24 +703,29 @@ static ssize_t unpack_perms_table(struct aa_ext *e, struct aa_perms **perms)
 	return -EPROTO;
 }
 
-static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
+static int unpack_pdb(struct aa_ext *e, struct aa_policydb **policy,
 		      bool required_dfa, bool required_trans,
 		      const char **info)
 {
+	struct aa_policydb *pdb;
 	void *pos = e->pos;
 	int i, flags, error = -EPROTO;
 	ssize_t size;
 
-	size = unpack_perms_table(e, &policy->perms);
+	pdb = aa_alloc_pdb(GFP_KERNEL);
+	if (!pdb)
+		return -ENOMEM;
+
+	size = unpack_perms_table(e, &pdb->perms);
 	if (size < 0) {
 		error = size;
-		policy->perms = NULL;
+		pdb->perms = NULL;
 		*info = "failed to unpack - perms";
 		goto fail;
 	}
-	policy->size = size;
+	pdb->size = size;
 
-	if (policy->perms) {
+	if (pdb->perms) {
 		/* perms table present accept is index */
 		flags = TO_ACCEPT1_FLAG(YYTD_DATA32);
 	} else {
@@ -729,13 +734,13 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
 			TO_ACCEPT2_FLAG(YYTD_DATA32);
 	}
 
-	policy->dfa = unpack_dfa(e, flags);
-	if (IS_ERR(policy->dfa)) {
-		error = PTR_ERR(policy->dfa);
-		policy->dfa = NULL;
+	pdb->dfa = unpack_dfa(e, flags);
+	if (IS_ERR(pdb->dfa)) {
+		error = PTR_ERR(pdb->dfa);
+		pdb->dfa = NULL;
 		*info = "failed to unpack - dfa";
 		goto fail;
-	} else if (!policy->dfa) {
+	} else if (!pdb->dfa) {
 		if (required_dfa) {
 			*info = "missing required dfa";
 			goto fail;
@@ -749,18 +754,18 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
 	 * sadly start was given different names for file and policydb
 	 * but since it is optional we can try both
 	 */
-	if (!aa_unpack_u32(e, &policy->start[0], "start"))
+	if (!aa_unpack_u32(e, &pdb->start[0], "start"))
 		/* default start state */
-		policy->start[0] = DFA_START;
-	if (!aa_unpack_u32(e, &policy->start[AA_CLASS_FILE], "dfa_start")) {
+		pdb->start[0] = DFA_START;
+	if (!aa_unpack_u32(e, &pdb->start[AA_CLASS_FILE], "dfa_start")) {
 		/* default start state for xmatch and file dfa */
-		policy->start[AA_CLASS_FILE] = DFA_START;
+		pdb->start[AA_CLASS_FILE] = DFA_START;
 	}	/* setup class index */
 	for (i = AA_CLASS_FILE + 1; i <= AA_CLASS_LAST; i++) {
-		policy->start[i] = aa_dfa_next(policy->dfa, policy->start[0],
+		pdb->start[i] = aa_dfa_next(pdb->dfa, pdb->start[0],
 					       i);
 	}
-	if (!unpack_trans_table(e, &policy->trans) && required_trans) {
+	if (!unpack_trans_table(e, &pdb->trans) && required_trans) {
 		*info = "failed to unpack profile transition table";
 		goto fail;
 	}
@@ -768,9 +773,11 @@ static int unpack_pdb(struct aa_ext *e, struct aa_policydb *policy,
 	/* TODO: move compat mapping here, requires dfa merging first */
 	/* TODO: move verify here, it has to be done after compat mappings */
 out:
+	*policy = pdb;
 	return 0;
 
 fail:
+	aa_put_pdb(pdb);
 	e->pos = pos;
 	return error;
 }
@@ -854,15 +861,15 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
 	}
 
 	/* neither xmatch_len not xmatch_perms are optional if xmatch is set */
-	if (profile->attach.xmatch.dfa) {
+	if (profile->attach.xmatch->dfa) {
 		if (!aa_unpack_u32(e, &tmp, NULL)) {
 			info = "missing xmatch len";
 			goto fail;
 		}
 		profile->attach.xmatch_len = tmp;
-		profile->attach.xmatch.start[AA_CLASS_XMATCH] = DFA_START;
-		if (!profile->attach.xmatch.perms) {
-			error = aa_compat_map_xmatch(&profile->attach.xmatch);
+		profile->attach.xmatch->start[AA_CLASS_XMATCH] = DFA_START;
+		if (!profile->attach.xmatch->perms) {
+			error = aa_compat_map_xmatch(profile->attach.xmatch);
 			if (error) {
 				info = "failed to convert xmatch permission table";
 				goto fail;
@@ -979,16 +986,16 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
 		if (error)
 			goto fail;
 		/* Fixup: drop when we get rid of start array */
-		if (aa_dfa_next(rules->policy.dfa, rules->policy.start[0],
+		if (aa_dfa_next(rules->policy->dfa, rules->policy->start[0],
 				AA_CLASS_FILE))
-			rules->policy.start[AA_CLASS_FILE] =
-			  aa_dfa_next(rules->policy.dfa,
-				      rules->policy.start[0],
+			rules->policy->start[AA_CLASS_FILE] =
+			  aa_dfa_next(rules->policy->dfa,
+				      rules->policy->start[0],
 				      AA_CLASS_FILE);
 		if (!aa_unpack_nameX(e, AA_STRUCTEND, NULL))
 			goto fail;
-		if (!rules->policy.perms) {
-			error = aa_compat_map_policy(&rules->policy,
+		if (!rules->policy->perms) {
+			error = aa_compat_map_policy(rules->policy,
 						     e->version);
 			if (error) {
 				info = "failed to remap policydb permission table";
@@ -996,44 +1003,25 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name)
 			}
 		}
 	} else {
-		rules->policy.dfa = aa_get_dfa(nulldfa);
-		rules->policy.perms = kcalloc(2, sizeof(struct aa_perms),
-					      GFP_KERNEL);
-		if (!rules->policy.perms)
-			goto fail;
-		rules->policy.size = 2;
+		rules->policy = aa_get_pdb(nullpdb);
 	}
 	/* get file rules */
 	error = unpack_pdb(e, &rules->file, false, true, &info);
 	if (error) {
 		goto fail;
-	} else if (rules->file.dfa) {
-		if (!rules->file.perms) {
-			error = aa_compat_map_file(&rules->file);
+	} else if (rules->file->dfa) {
+		if (!rules->file->perms) {
+			error = aa_compat_map_file(rules->file);
 			if (error) {
 				info = "failed to remap file permission table";
 				goto fail;
 			}
 		}
-	} else if (rules->policy.dfa &&
-		   rules->policy.start[AA_CLASS_FILE]) {
-		rules->file.dfa = aa_get_dfa(rules->policy.dfa);
-		rules->file.start[AA_CLASS_FILE] = rules->policy.start[AA_CLASS_FILE];
-		rules->file.perms = kcalloc(rules->policy.size,
-					    sizeof(struct aa_perms),
-					    GFP_KERNEL);
-		if (!rules->file.perms)
-			goto fail;
-		memcpy(rules->file.perms, rules->policy.perms,
-		       rules->policy.size * sizeof(struct aa_perms));
-		rules->file.size = rules->policy.size;
+	} else if (rules->policy->dfa &&
+		   rules->policy->start[AA_CLASS_FILE]) {
+		rules->file = aa_get_pdb(rules->policy);
 	} else {
-		rules->file.dfa = aa_get_dfa(nulldfa);
-		rules->file.perms = kcalloc(2, sizeof(struct aa_perms),
-					    GFP_KERNEL);
-		if (!rules->file.perms)
-			goto fail;
-		rules->file.size = 2;
+		rules->file = aa_get_pdb(nullpdb);
 	}
 	error = -EPROTO;
 	if (aa_unpack_nameX(e, AA_STRUCT, "data")) {
@@ -1240,32 +1228,32 @@ static int verify_profile(struct aa_profile *profile)
 	if (!rules)
 		return 0;
 
-	if (rules->file.dfa && !verify_dfa_accept_index(rules->file.dfa,
-							rules->file.size)) {
+	if (rules->file->dfa && !verify_dfa_accept_index(rules->file->dfa,
+							rules->file->size)) {
 		audit_iface(profile, NULL, NULL,
 			    "Unpack: file Invalid named transition", NULL,
 			    -EPROTO);
 		return -EPROTO;
 	}
-	if (rules->policy.dfa &&
-	    !verify_dfa_accept_index(rules->policy.dfa, rules->policy.size)) {
+	if (rules->policy->dfa &&
+	    !verify_dfa_accept_index(rules->policy->dfa, rules->policy->size)) {
 		audit_iface(profile, NULL, NULL,
 			    "Unpack: policy Invalid named transition", NULL,
 			    -EPROTO);
 		return -EPROTO;
 	}
 
-	if (!verify_perms(&rules->file)) {
+	if (!verify_perms(rules->file)) {
 		audit_iface(profile, NULL, NULL,
 			    "Unpack: Invalid perm index", NULL, -EPROTO);
 		return -EPROTO;
 	}
-	if (!verify_perms(&rules->policy)) {
+	if (!verify_perms(rules->policy)) {
 		audit_iface(profile, NULL, NULL,
 			    "Unpack: Invalid perm index", NULL, -EPROTO);
 		return -EPROTO;
 	}
-	if (!verify_perms(&profile->attach.xmatch)) {
+	if (!verify_perms(profile->attach.xmatch)) {
 		audit_iface(profile, NULL, NULL,
 			    "Unpack: Invalid perm index", NULL, -EPROTO);
 		return -EPROTO;