apparmor: compute policydb permission on profile load

Rather than computing policydb permissions for each access
permissions can be computed once on profile load and stored for lookup.

Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 18 insertions, 35 deletions

diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c
index f61247241803..1e978c2b1ee4 100644
--- a/security/apparmor/mount.c
+++ b/security/apparmor/mount.c
@@ -203,25 +203,6 @@ static unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state,
 	return state;
 }
 
-/**
- * compute_mnt_perms - compute mount permission associated with @state
- * @dfa: dfa to match against (NOT NULL)
- * @state: state match finished in
- *
- * Returns: mount permissions
- */
-static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa,
-					   unsigned int state)
-{
-	struct aa_perms perms = {
-		.allow = dfa_user_allow(dfa, state),
-		.audit = dfa_user_audit(dfa, state),
-		.quiet = dfa_user_quiet(dfa, state),
-	};
-
-	return perms;
-}
-
 static const char * const mnt_info_table[] = {
 	"match succeeded",
 	"failed mntpnt match",
@@ -236,50 +217,52 @@ static const char * const mnt_info_table[] = {
  * Returns 0 on success else element that match failed in, this is the
  * index into the mnt_info_table above
  */
-static int do_match_mnt(struct aa_dfa *dfa, unsigned int start,
+static int do_match_mnt(struct aa_policydb *policy, unsigned int start,
 			const char *mntpnt, const char *devname,
 			const char *type, unsigned long flags,
 			void *data, bool binary, struct aa_perms *perms)
 {
 	unsigned int state;
 
-	AA_BUG(!dfa);
+	AA_BUG(!policy);
+	AA_BUG(!policy->dfa);
+	AA_BUG(!policy->perms);
 	AA_BUG(!perms);
 
-	state = aa_dfa_match(dfa, start, mntpnt);
-	state = aa_dfa_null_transition(dfa, state);
+	state = aa_dfa_match(policy->dfa, start, mntpnt);
+	state = aa_dfa_null_transition(policy->dfa, state);
 	if (!state)
 		return 1;
 
 	if (devname)
-		state = aa_dfa_match(dfa, state, devname);
-	state = aa_dfa_null_transition(dfa, state);
+		state = aa_dfa_match(policy->dfa, state, devname);
+	state = aa_dfa_null_transition(policy->dfa, state);
 	if (!state)
 		return 2;
 
 	if (type)
-		state = aa_dfa_match(dfa, state, type);
-	state = aa_dfa_null_transition(dfa, state);
+		state = aa_dfa_match(policy->dfa, state, type);
+	state = aa_dfa_null_transition(policy->dfa, state);
 	if (!state)
 		return 3;
 
-	state = match_mnt_flags(dfa, state, flags);
+	state = match_mnt_flags(policy->dfa, state, flags);
 	if (!state)
 		return 4;
-	*perms = compute_mnt_perms(dfa, state);
+	*perms = *aa_lookup_perms(policy->perms, state);
 	if (perms->allow & AA_MAY_MOUNT)
 		return 0;
 
 	/* only match data if not binary and the DFA flags data is expected */
 	if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
-		state = aa_dfa_null_transition(dfa, state);
+		state = aa_dfa_null_transition(policy->dfa, state);
 		if (!state)
 			return 4;
 
-		state = aa_dfa_match(dfa, state, data);
+		state = aa_dfa_match(policy->dfa, state, data);
 		if (!state)
 			return 5;
-		*perms = compute_mnt_perms(dfa, state);
+		*perms = *aa_lookup_perms(policy->perms, state);
 		if (perms->allow & AA_MAY_MOUNT)
 			return 0;
 	}
@@ -341,7 +324,7 @@ static int match_mnt_path_str(struct aa_profile *profile,
 	}
 
 	error = -EACCES;
-	pos = do_match_mnt(profile->policy.dfa,
+	pos = do_match_mnt(&profile->policy,
 			   profile->policy.start[AA_CLASS_MOUNT],
 			   mntpnt, devname, type, flags, data, binary, &perms);
 	if (pos) {
@@ -601,7 +584,7 @@ static int profile_umount(struct aa_profile *profile, const struct path *path,
 	state = aa_dfa_match(profile->policy.dfa,
 			     profile->policy.start[AA_CLASS_MOUNT],
 			     name);
-	perms = compute_mnt_perms(profile->policy.dfa, state);
+	perms = *aa_lookup_perms(profile->policy.perms, state);
 	if (AA_MAY_UMOUNT & ~perms.allow)
 		error = -EACCES;
 
@@ -672,7 +655,7 @@ static struct aa_label *build_pivotroot(struct aa_profile *profile,
 			     new_name);
 	state = aa_dfa_null_transition(profile->policy.dfa, state);
 	state = aa_dfa_match(profile->policy.dfa, state, old_name);
-	perms = compute_mnt_perms(profile->policy.dfa, state);
+	perms = *aa_lookup_perms(profile->policy.perms, state);
 
 	if (AA_MAY_PIVOTROOT & perms.allow)
 		error = 0;