Refactor ciphersuite selection for version > 2
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 530c866..ffd73e2 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -974,6 +974,59 @@
}
#endif /* POLARSSL_X509_CRT_PARSE_C */
+/*
+ * Check if a given ciphersuite is suitable for use with our config/keys/etc
+ * Sets ciphersuite_info only if the suite matches.
+ */
+static int ssl_ciphersuite_match( ssl_context *ssl, int suite_id,
+ const ssl_ciphersuite_t **ciphersuite_info )
+{
+ const ssl_ciphersuite_t *suite_info;
+
+ suite_info = ssl_ciphersuite_from_id( suite_id );
+ if( suite_info == NULL )
+ {
+ SSL_DEBUG_MSG( 1, ( "ciphersuite info for %04x not found", suite_id ) );
+ return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+ }
+
+ if( suite_info->min_minor_ver > ssl->minor_ver ||
+ suite_info->max_minor_ver < ssl->minor_ver )
+ return( 0 );
+
+#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
+ if( ssl_ciphersuite_uses_ec( suite_info ) &&
+ ( ssl->handshake->curves == NULL ||
+ ssl->handshake->curves[0] == NULL ) )
+ return( 0 );
+#endif
+
+#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
+ /* If the ciphersuite requires a pre-shared key and we don't
+ * have one, skip it now rather than failing later */
+ if( ssl_ciphersuite_uses_psk( suite_info ) &&
+ ssl->f_psk == NULL &&
+ ( ssl->psk == NULL || ssl->psk_identity == NULL ||
+ ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) )
+ return( 0 );
+#endif
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+ /*
+ * Final check: if ciphersuite requires us to have a
+ * certificate/key of a particular type:
+ * - select the appropriate certificate if we have one, or
+ * - try the next ciphersuite if we don't
+ * This must be done last since we modify the key_cert list.
+ */
+ if( ssl_pick_cert( ssl, suite_info ) != 0 )
+ return( 0 );
+#endif
+
+ *ciphersuite_info = suite_info;
+ return( 0 );
+}
+
static int ssl_parse_client_hello( ssl_context *ssl )
{
int ret;
@@ -1372,6 +1425,7 @@
* and certificate from the SNI callback triggered by the SNI extension.)
*/
ciphersuites = ssl->ciphersuite_list[ssl->minor_ver];
+ ciphersuite_info = NULL;
for( i = 0; ciphersuites[i] != 0; i++ )
{
for( j = 0, p = buf + 41 + sess_len; j < ciph_len;
@@ -1380,49 +1434,12 @@
if( p[0] == ( ( ciphersuites[i] >> 8 ) & 0xFF ) &&
p[1] == ( ( ciphersuites[i] ) & 0xFF ) )
{
- ciphersuite_info = ssl_ciphersuite_from_id( ciphersuites[i] );
+ if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
+ &ciphersuite_info ) ) != 0 )
+ return( ret );
- if( ciphersuite_info == NULL )
- {
- SSL_DEBUG_MSG( 1, ( "ciphersuite info for %04x not found",
- ciphersuites[i] ) );
- return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
- }
-
- if( ciphersuite_info->min_minor_ver > ssl->minor_ver ||
- ciphersuite_info->max_minor_ver < ssl->minor_ver )
- continue;
-
-#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
- if( ssl_ciphersuite_uses_ec( ciphersuite_info ) &&
- ( ssl->handshake->curves == NULL ||
- ssl->handshake->curves[0] == NULL ) )
- continue;
-#endif
-
-#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
- /* If the ciphersuite requires a pre-shared key and we don't
- * have one, skip it now rather than failing later */
- if( ssl_ciphersuite_uses_psk( ciphersuite_info ) &&
- ssl->f_psk == NULL &&
- ( ssl->psk == NULL || ssl->psk_identity == NULL ||
- ssl->psk_identity_len == 0 || ssl->psk_len == 0 ) )
- continue;
-#endif
-
-#if defined(POLARSSL_X509_CRT_PARSE_C)
- /*
- * Final check: if ciphersuite requires us to have a
- * certificate/key of a particular type:
- * - select the appropriate certificate if we have one, or
- * - try the next ciphersuite if we don't
- * This must be done last since we modify the key_cert list.
- */
- if( ssl_pick_cert( ssl, ciphersuite_info ) != 0 )
- continue;
-#endif
-
- goto have_ciphersuite;
+ if( ciphersuite_info != NULL )
+ goto have_ciphersuite;
}
}
}