Smack: network label match fix

The Smack code that matches incoming CIPSO tags with Smack labels
reaches through the NetLabel interfaces and compares the network
data with the CIPSO header associated with a Smack label. This was
done in a ill advised attempt to optimize performance. It works
so long as the categories fit in a single capset, but this isn't
always the case.

This patch changes the Smack code to use the appropriate NetLabel
interfaces to compare the incoming CIPSO header with the CIPSO
header associated with a label. It will always match the CIPSO
headers correctly.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

1 files changed, 24 insertions, 6 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index ce000a81caf7..19204e11c02c 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3066,6 +3066,8 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 {
 	struct smack_known *skp;
 	int found = 0;
+	int acat;
+	int kcat;
 
 	if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
 		/*
@@ -3082,12 +3084,28 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 		list_for_each_entry(skp, &smack_known_list, list) {
 			if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
 				continue;
-			if (memcmp(sap->attr.mls.cat,
-				skp->smk_netlabel.attr.mls.cat,
-				SMK_CIPSOLEN) != 0)
-				continue;
-			found = 1;
-			break;
+			/*
+			 * Compare the catsets. Use the netlbl APIs.
+			 */
+			if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
+				if ((skp->smk_netlabel.flags &
+				     NETLBL_SECATTR_MLS_CAT) == 0)
+					found = 1;
+				break;
+			}
+			for (acat = -1, kcat = -1; acat == kcat; ) {
+				acat = netlbl_secattr_catmap_walk(
+					sap->attr.mls.cat, acat + 1);
+				kcat = netlbl_secattr_catmap_walk(
+					skp->smk_netlabel.attr.mls.cat,
+					kcat + 1);
+				if (acat < 0 || kcat < 0)
+					break;
+			}
+			if (acat == kcat) {
+				found = 1;
+				break;
+			}
 		}
 		rcu_read_unlock();