From 73cd8d8adc3a436a457aed51c826e62326283da0 Mon Sep 17 00:00:00 2001
From: Hanno Becker <hanno.becker@arm.com>
Date: Thu, 28 Feb 2019 14:04:16 +0000
Subject: [PATCH] Make use of acquire/release in ssl_parse_certificate_verify()

---
 library/ssl_srv.c | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index fbe895646..f661d11e6 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -4237,7 +4237,16 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
         peer_pk = &ssl->handshake->peer_pubkey;
 #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     if( ssl->session_negotiate->peer_cert != NULL )
-        peer_pk = &ssl->session_negotiate->peer_cert->pk;
+    {
+        ret = mbedtls_x509_crt_pk_acquire( ssl->session_negotiate->peer_cert,
+                                           &peer_pk );
+        if( ret != 0 )
+        {
+            /* Should never happen */
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+        }
+    }
 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
     if( peer_pk == NULL )
@@ -4297,7 +4306,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
         if( i + 2 > ssl->in_hslen )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
-            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+            goto exit;
         }
 
         /*
@@ -4309,7 +4319,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
                                 " for verify message" ) );
-            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+            goto exit;
         }
 
 #if !defined(MBEDTLS_MD_SHA1)
@@ -4330,7 +4341,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
                                 " for verify message" ) );
-            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+            goto exit;
         }
 
         /*
@@ -4339,7 +4351,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
         if( !mbedtls_pk_can_do( peer_pk, pk_alg ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
-            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+            ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+            goto exit;
         }
 
         i++;
@@ -4354,7 +4367,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
     if( i + 2 > ssl->in_hslen )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
-        return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+        ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+        goto exit;
     }
 
     sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
@@ -4363,7 +4377,8 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
     if( i + sig_len != ssl->in_hslen )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
-        return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
+        ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY;
+        goto exit;
     }
 
     /* Calculate hash and verify signature */
@@ -4377,13 +4392,20 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
                            ssl->in_msg + i, sig_len ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
-        return( ret );
+        goto exit;
     }
 
     mbedtls_ssl_update_handshake_status( ssl );
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
 
+exit:
+
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+    mbedtls_x509_crt_pk_release( ssl->session_negotiate->peer_cert,
+                                 peer_pk );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
     return( ret );
 }
 #endif /* MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */