commit 9f1176a79313f652da960fc515fc9e5cd148203a
author Neil Armstrong <narmstrong@baylibre.com> Fri Jun 24 18:19:19 2022 +0200
committer Neil Armstrong <narmstrong@baylibre.com> Tue Jun 28 18:12:17 2022 +0200
tree dceb82d97375427346dbcfac5e374920c969e15f
parent ed917bf548aeb68b4004b890379d76e481addf85

Move preferred_hash_for_sig_alg() check after ssl_pick_cert() and check if hash alg is supported with mbedtls_pk_can_do_ext()

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5fa02d2..23a12d2 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7691,10 +7691,53 @@
 
     for( i = 0; received_sig_algs[i] != MBEDTLS_TLS_SIG_NONE; i++ )
     {
-        if( sig_alg == MBEDTLS_SSL_TLS12_SIG_ALG_FROM_SIG_AND_HASH_ALG(
-                            received_sig_algs[i] ) )
-            return( MBEDTLS_SSL_TLS12_HASH_ALG_FROM_SIG_AND_HASH_ALG(
-                        received_sig_algs[i] ) );
+        unsigned int hash_alg_received =
+                    MBEDTLS_SSL_TLS12_HASH_ALG_FROM_SIG_AND_HASH_ALG(
+                        received_sig_algs[i] );
+        unsigned int sig_alg_received =
+                    MBEDTLS_SSL_TLS12_SIG_ALG_FROM_SIG_AND_HASH_ALG(
+                        received_sig_algs[i] );
+
+        if( sig_alg == sig_alg_received )
+        {
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+            if( ssl->handshake->key_cert && ssl->handshake->key_cert->key )
+            {
+                psa_algorithm_t alg = PSA_ALG_NONE;
+                psa_algorithm_t alg2 = PSA_ALG_NONE;
+                psa_key_usage_t usage = 0;
+                psa_key_usage_t usage2 = 0;
+
+                if( sig_alg_received == MBEDTLS_SSL_SIG_ECDSA )
+                {
+
+                    alg = PSA_ALG_ECDSA(
+                                mbedtls_psa_translate_md( hash_alg_received ) );
+                    usage = PSA_KEY_USAGE_SIGN_HASH;
+                    alg2 = PSA_ALG_ECDH;
+                    usage2 = PSA_KEY_USAGE_DERIVE;
+                }
+                else if( sig_alg_received == MBEDTLS_SSL_SIG_RSA )
+                {
+                    alg = PSA_ALG_RSA_PKCS1V15_SIGN(
+                                mbedtls_psa_translate_md( hash_alg_received ) );
+                    usage = PSA_KEY_USAGE_SIGN_HASH;
+                    alg2 = PSA_ALG_RSA_PKCS1V15_CRYPT;
+                    usage2 = PSA_KEY_USAGE_DECRYPT;
+                }
+                else
+                    continue;
+
+                if( ! mbedtls_pk_can_do_ext( ssl->handshake->key_cert->key,
+                                             alg, usage ) &&
+                    ! mbedtls_pk_can_do_ext( ssl->handshake->key_cert->key,
+                                             alg2, usage2 ) )
+                    continue;
+            }
+
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+            return( hash_alg_received );
+        }
     }
 
     return( MBEDTLS_SSL_HASH_NONE );

library/ssl_tls12_server.c

diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index 2e2a573..7258230 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -843,21 +843,6 @@
     }
 #endif
 
-#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
-    /* If the ciphersuite requires signing, check whether
-     * a suitable hash algorithm is present. */
-    sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
-    if( sig_type != MBEDTLS_PK_NONE &&
-        mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
-            ssl, mbedtls_ssl_sig_from_pk_alg( sig_type ) ) == MBEDTLS_SSL_HASH_NONE )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
-                                    "for signature algorithm %u", (unsigned) sig_type ) );
-        return( 0 );
-    }
-
-#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
-
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
     /*
      * Final check: if ciphersuite requires us to have a
@@ -874,6 +859,21 @@
     }
 #endif
 
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+    /* If the ciphersuite requires signing, check whether
+     * a suitable hash algorithm is present. */
+    sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
+    if( sig_type != MBEDTLS_PK_NONE &&
+        mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
+            ssl, mbedtls_ssl_sig_from_pk_alg( sig_type ) ) == MBEDTLS_SSL_HASH_NONE )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
+                                    "for signature algorithm %u", (unsigned) sig_type ) );
+        return( 0 );
+    }
+
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
     *ciphersuite_info = suite_info;
     return( 0 );
 }