Fix return type of example key export callbacks

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/programs/ssl/ssl_test_common_source.c b/programs/ssl/ssl_test_common_source.c
index 6da0ba4..d30c36e 100644
--- a/programs/ssl/ssl_test_common_source.c
+++ b/programs/ssl/ssl_test_common_source.c
@@ -25,47 +25,44 @@
  */
 
 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
-int eap_tls_key_derivation( void *p_expkey,
-                            mbedtls_ssl_key_export_type secret_type,
-                            const unsigned char *secret,
-                            size_t secret_len,
-                            const unsigned char client_random[32],
-                            const unsigned char server_random[32],
-                            mbedtls_tls_prf_types tls_prf_type )
+void eap_tls_key_derivation( void *p_expkey,
+                             mbedtls_ssl_key_export_type secret_type,
+                             const unsigned char *secret,
+                             size_t secret_len,
+                             const unsigned char client_random[32],
+                             const unsigned char server_random[32],
+                             mbedtls_tls_prf_types tls_prf_type )
 {
     eap_tls_keys *keys = (eap_tls_keys *)p_expkey;
 
     /* We're only interested in the TLS 1.2 master secret */
     if( secret_type != MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET )
-        return( 0 );
+        return;
     if( secret_len != sizeof( keys->master_secret ) )
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+        return;
 
     memcpy( keys->master_secret, secret, sizeof( keys->master_secret ) );
     memcpy( keys->randbytes, client_random, 32 );
     memcpy( keys->randbytes + 32, server_random, 32 );
     keys->tls_prf_type = tls_prf_type;
-
-    return( 0 );
 }
 
-int nss_keylog_export( void *p_expkey,
-                       mbedtls_ssl_key_export_type secret_type,
-                       const unsigned char *secret,
-                       size_t secret_len,
-                       const unsigned char client_random[32],
-                       const unsigned char server_random[32],
-                       mbedtls_tls_prf_types tls_prf_type )
+void nss_keylog_export( void *p_expkey,
+                        mbedtls_ssl_key_export_type secret_type,
+                        const unsigned char *secret,
+                        size_t secret_len,
+                        const unsigned char client_random[32],
+                        const unsigned char server_random[32],
+                        mbedtls_tls_prf_types tls_prf_type )
 {
     char nss_keylog_line[ 200 ];
     size_t const client_random_len = 32;
     size_t len = 0;
     size_t j;
-    int ret = 0;
 
     /* We're only interested in the TLS 1.2 master secret */
     if( secret_type != MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET )
-        return( 0 );
+        return;
 
     ((void) p_expkey);
     ((void) server_random);
@@ -102,13 +99,11 @@
 
         if( ( f = fopen( opt.nss_keylog_file, "a" ) ) == NULL )
         {
-            ret = -1;
             goto exit;
         }
 
         if( fwrite( nss_keylog_line, 1, len, f ) != len )
         {
-            ret = -1;
             fclose( f );
             goto exit;
         }
@@ -119,32 +114,29 @@
 exit:
     mbedtls_platform_zeroize( nss_keylog_line,
                               sizeof( nss_keylog_line ) );
-    return( ret );
 }
 
 #if defined( MBEDTLS_SSL_DTLS_SRTP )
-int dtls_srtp_key_derivation( void *p_expkey,
-                              mbedtls_ssl_key_export_type secret_type,
-                              const unsigned char *secret,
-                              size_t secret_len,
-                              const unsigned char client_random[32],
-                              const unsigned char server_random[32],
-                              mbedtls_tls_prf_types tls_prf_type )
+void dtls_srtp_key_derivation( void *p_expkey,
+                               mbedtls_ssl_key_export_type secret_type,
+                               const unsigned char *secret,
+                               size_t secret_len,
+                               const unsigned char client_random[32],
+                               const unsigned char server_random[32],
+                               mbedtls_tls_prf_types tls_prf_type )
 {
     dtls_srtp_keys *keys = (dtls_srtp_keys *)p_expkey;
 
     /* We're only interested in the TLS 1.2 master secret */
     if( secret_type != MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET )
-        return( 0 );
+        return;
     if( secret_len != sizeof( keys->master_secret ) )
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+        return;
 
     memcpy( keys->master_secret, secret, sizeof( keys->master_secret ) );
     memcpy( keys->randbytes, client_random, 32 );
     memcpy( keys->randbytes + 32, server_random, 32 );
     keys->tls_prf_type = tls_prf_type;
-
-    return( 0 );
 }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */