tls: Fix AEAD algorithm filtering, avoid filtering all suites if no AEAD found

1 files changed, 52 insertions, 19 deletions

diff --git a/src/libtls/tls_crypto.c b/src/libtls/tls_crypto.c
index a4e24543b..c1ed57ae6 100644
--- a/src/libtls/tls_crypto.c
+++ b/src/libtls/tls_crypto.c
@@ -648,7 +648,7 @@ static suite_algs_t *find_suite(tls_cipher_suite_t suite)
 /**
  * Filter a suite list using a transform enumerator
  */
-static void filter_suite(private_tls_crypto_t *this, bool aead,
+static void filter_suite(private_tls_crypto_t *this,
 						 suite_algs_t suites[], int *count, int offset,
 						 enumerator_t*(*create_enumerator)(crypto_factory_t*))
 {
@@ -662,23 +662,56 @@ static void filter_suite(private_tls_crypto_t *this, bool aead,
 
 	for (i = 0; i < *count; i++)
 	{
+		if (create_enumerator == lib->crypto->create_crypter_enumerator &&
+			encryption_algorithm_is_aead(suites[i].encr))
+		{	/* filtering crypters, but current suite uses an AEAD, apply */
+			suites[remaining] = suites[i];
+			remaining++;
+			continue;
+		}
+		if (create_enumerator == lib->crypto->create_aead_enumerator &&
+			!encryption_algorithm_is_aead(suites[i].encr))
+		{	/* filtering AEADs, but current suite doesn't use one, apply */
+			suites[remaining] = suites[i];
+			remaining++;
+			continue;
+		}
 		enumerator = create_enumerator(lib->crypto);
 		while (enumerator->enumerate(enumerator, current_alg, &plugin_name))
 		{
-			if ((suites[i].encr == ENCR_NULL ||
-				 aead != encryption_algorithm_is_aead(suites[i].encr) ||
-				 !current.encr || current.encr == suites[i].encr) &&
-				(suites[i].mac == AUTH_UNDEFINED ||
-				 !current.mac  || current.mac  == suites[i].mac) &&
-				(!current.prf  || current.prf  == suites[i].prf) &&
-				(!current.hash || current.hash == suites[i].hash) &&
-				(suites[i].dh == MODP_NONE ||
-				 !current.dh   || current.dh   == suites[i].dh))
+			if (current.encr && current.encr != suites[i].encr)
 			{
-				suites[remaining] = suites[i];
-				remaining++;
-				break;
+				if (suites[i].encr != ENCR_NULL)
+				{	/* skip, ENCR does not match nor is NULL */
+					continue;
+				}
 			}
+			if (current.mac && current.mac != suites[i].mac)
+			{
+				if (suites[i].mac != AUTH_UNDEFINED)
+				{	/* skip, MAC does not match nor is it undefined */
+					continue;
+				}
+			}
+			if (current.prf && current.prf != suites[i].prf)
+			{	/* skip, PRF does not match */
+				continue;
+			}
+			if (current.hash && current.hash != suites[i].hash)
+			{	/* skip, hash does not match */
+				continue;
+			}
+			if (current.dh && current.dh != suites[i].dh)
+			{
+				if (suites[i].dh != MODP_NONE)
+				{	/* skip DH group, does not match nor NONE */
+					continue;
+				}
+			}
+			/* suite supported, apply */
+			suites[remaining] = suites[i];
+			remaining++;
+			break;
 		}
 		enumerator->destroy(enumerator);
 	}
@@ -969,17 +1002,17 @@ static void build_cipher_suite_list(private_tls_crypto_t *this,
 	}
 
 	/* filter suite list by each algorithm */
-	filter_suite(this, FALSE, suites, &count, offsetof(suite_algs_t, encr),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, encr),
 				 lib->crypto->create_crypter_enumerator);
-	filter_suite(this, TRUE, suites, &count, offsetof(suite_algs_t, encr),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, encr),
 				 lib->crypto->create_aead_enumerator);
-	filter_suite(this, FALSE, suites, &count, offsetof(suite_algs_t, mac),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, mac),
 				 lib->crypto->create_signer_enumerator);
-	filter_suite(this, FALSE, suites, &count, offsetof(suite_algs_t, prf),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, prf),
 				 lib->crypto->create_prf_enumerator);
-	filter_suite(this, FALSE, suites, &count, offsetof(suite_algs_t, hash),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, hash),
 				 lib->crypto->create_hasher_enumerator);
-	filter_suite(this, FALSE, suites, &count, offsetof(suite_algs_t, dh),
+	filter_suite(this, suites, &count, offsetof(suite_algs_t, dh),
 				 lib->crypto->create_dh_enumerator);
 
 	/* filter suites with strongswan.conf options */