Add check to s2n_signature_scheme_valid_to_accept (#3728)

Co-authored-by: Harrison Kaiser <[email protected]>
aws · Jan 5, 2023 · 41cfe12 · 41cfe12
1 parent 2663f20
commit 41cfe12
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Showing 2 changed files with 14 additions and 0 deletions.
diff --git a/tests/unit/s2n_tls13_cert_verify_test.c b/tests/unit/s2n_tls13_cert_verify_test.c
@@ -62,6 +62,7 @@ int run_tests(const struct s2n_tls13_cert_verify_test *test_case, s2n_mode verif
 
         struct s2n_connection *verifying_conn = NULL, *sending_conn = NULL;
         EXPECT_NOT_NULL(verifying_conn = s2n_connection_new(verifier_mode));
+        verifying_conn->actual_protocol_version = S2N_TLS13;
         EXPECT_NOT_NULL(sending_conn = s2n_connection_new(verifier_mode == S2N_CLIENT ? S2N_SERVER : S2N_CLIENT));
 
         EXPECT_SUCCESS(s2n_stuffer_alloc(&certificate_in, S2N_MAX_TEST_PEM_SIZE));
@@ -154,6 +155,7 @@ int run_tests(const struct s2n_tls13_cert_verify_test *test_case, s2n_mode verif
 
         struct s2n_connection *verifying_conn = NULL;
         EXPECT_NOT_NULL(verifying_conn = s2n_connection_new(verifier_mode));
+        verifying_conn->actual_protocol_version = S2N_TLS13;
         EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(config, cert_chain));
         EXPECT_SUCCESS(s2n_connection_set_config(verifying_conn, config));
         verifying_conn->handshake_params.our_chain_and_key = cert_chain;
@@ -222,6 +224,7 @@ int run_tests(const struct s2n_tls13_cert_verify_test *test_case, s2n_mode verif
 
         struct s2n_connection *verifying_conn = NULL;
         EXPECT_NOT_NULL(verifying_conn = s2n_connection_new(verifier_mode));
+        verifying_conn->actual_protocol_version = S2N_TLS13;
         EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(config, cert_chain));
         EXPECT_SUCCESS(s2n_connection_set_config(verifying_conn, config));
         verifying_conn->handshake_params.our_chain_and_key = cert_chain;

diff --git a/tls/s2n_signature_algorithms.c b/tls/s2n_signature_algorithms.c
@@ -28,6 +28,8 @@
 
 static int s2n_signature_scheme_valid_to_offer(struct s2n_connection *conn, const struct s2n_signature_scheme *scheme)
 {
+    POSIX_ENSURE_REF(conn);
+
     /* We don't know what protocol version we will eventually negotiate, but we know that it won't be any higher. */
     POSIX_ENSURE_GTE(conn->actual_protocol_version, scheme->minimum_protocol_version);
 
@@ -50,13 +52,22 @@ static int s2n_signature_scheme_valid_to_offer(struct s2n_connection *conn, cons
 static int s2n_signature_scheme_valid_to_accept(struct s2n_connection *conn, const struct s2n_signature_scheme *scheme)
 {
     POSIX_ENSURE_REF(scheme);
+    POSIX_ENSURE_REF(conn);
 
     POSIX_GUARD(s2n_signature_scheme_valid_to_offer(conn, scheme));
 
     if (scheme->maximum_protocol_version != S2N_UNKNOWN_PROTOCOL_VERSION) {
         POSIX_ENSURE_LTE(conn->actual_protocol_version, scheme->maximum_protocol_version);
     }
 
+    POSIX_ENSURE_NE(conn->actual_protocol_version, S2N_UNKNOWN_PROTOCOL_VERSION);
+    if (conn->actual_protocol_version >= S2N_TLS13) {
+        POSIX_ENSURE_NE(scheme->hash_alg, S2N_HASH_SHA1);
+        POSIX_ENSURE_NE(scheme->sig_alg, S2N_SIGNATURE_RSA);
+    } else {
+        POSIX_ENSURE_NE(scheme->sig_alg, S2N_SIGNATURE_RSA_PSS_PSS);
+    }
+
     return 0;
 }