Add int return values to MD2 function calls

The following function calls are being deprecated to introduce int
return values.
    * mbedtls_md2()
    * mbedtls_md2_starts()
    * mbedtls_md2_update()
    * mbedtls_md2_finish()
    * mbedtls_md2_process()
The return codes can be used to return error values. This is important
when using hardware accelerators.

library/md2.c

@@ -105,16 +105,18 @@ void mbedtls_md2_clone( mbedtls_md2_context *dst,
 /*
  * MD2 context setup
  */
-void mbedtls_md2_starts( mbedtls_md2_context *ctx )
+int mbedtls_md2_starts_ext( mbedtls_md2_context *ctx )
 {
     memset( ctx->cksum, 0, 16 );
     memset( ctx->state, 0, 46 );
     memset( ctx->buffer, 0, 16 );
     ctx->left = 0;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_MD2_PROCESS_ALT)
-void mbedtls_md2_process( mbedtls_md2_context *ctx )
+int mbedtls_md2_process_ext( mbedtls_md2_context *ctx )
 {
     int i, j;
     unsigned char t = 0;
@@ -146,14 +148,19 @@ void mbedtls_md2_process( mbedtls_md2_context *ctx )
            ( ctx->cksum[i] ^ PI_SUBST[ctx->buffer[i] ^ t] );
         t  = ctx->cksum[i];
     }
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_MD2_PROCESS_ALT */
 
 /*
  * MD2 process buffer
  */
-void mbedtls_md2_update( mbedtls_md2_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_md2_update_ext( mbedtls_md2_context *ctx,
+                            const unsigned char *input,
+                            size_t ilen )
 {
+    int ret;
     size_t fill;
 
     while( ilen > 0 )
@@ -172,16 +179,21 @@ void mbedtls_md2_update( mbedtls_md2_context *ctx, const unsigned char *input, s
         if( ctx->left == 16 )
         {
             ctx->left = 0;
-            mbedtls_md2_process( ctx );
+            if( ( ret = mbedtls_md2_process_ext( ctx ) ) != 0 )
+                return( ret );
         }
     }
+
+    return( 0 );
 }
 
 /*
  * MD2 final digest
  */
-void mbedtls_md2_finish( mbedtls_md2_context *ctx, unsigned char output[16] )
+int mbedtls_md2_finish_ext( mbedtls_md2_context *ctx,
+                            unsigned char output[16] )
 {
+    int ret;
     size_t i;
     unsigned char x;
 
@@ -190,12 +202,16 @@ void mbedtls_md2_finish( mbedtls_md2_context *ctx, unsigned char output[16] )
     for( i = ctx->left; i < 16; i++ )
         ctx->buffer[i] = x;
 
-    mbedtls_md2_process( ctx );
+    if( ( ret = mbedtls_md2_process_ext( ctx ) ) != 0 )
+        return( ret );
 
     memcpy( ctx->buffer, ctx->cksum, 16 );
-    mbedtls_md2_process( ctx );
+    if( ( ret = mbedtls_md2_process_ext( ctx ) ) != 0 )
+        return( ret );
 
     memcpy( output, ctx->state, 16 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_MD2_ALT */
@@ -203,15 +219,28 @@ void mbedtls_md2_finish( mbedtls_md2_context *ctx, unsigned char output[16] )
 /*
  * output = MD2( input buffer )
  */
-void mbedtls_md2( const unsigned char *input, size_t ilen, unsigned char output[16] )
+int mbedtls_md2_ext( const unsigned char *input,
+                     size_t ilen,
+                     unsigned char output[16] )
 {
+    int ret;
     mbedtls_md2_context ctx;
 
     mbedtls_md2_init( &ctx );
-    mbedtls_md2_starts( &ctx );
-    mbedtls_md2_update( &ctx, input, ilen );
-    mbedtls_md2_finish( &ctx, output );
+
+    if( ( ret = mbedtls_md2_starts_ext( &ctx ) ) != 0 )
+        return( ret );
+
+    if( ( ret = mbedtls_md2_update_ext( &ctx, input, ilen ) ) != 0 )
+        return( ret );
+
+    if( ( ret = mbedtls_md2_finish_ext( &ctx, output ) ) != 0 )
+        return( ret );
+
+
     mbedtls_md2_free( &ctx );
+
+    return( 0 );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -262,16 +291,12 @@ int mbedtls_md2_self_test( int verbose )
         if( verbose != 0 )
             mbedtls_printf( "  MD2 test #%d: ", i + 1 );
 
-        mbedtls_md2( (unsigned char *) md2_test_str[i],
-             strlen( md2_test_str[i] ), md2sum );
+        if( mbedtls_md2_ext( (unsigned char *)md2_test_str[i],
+                             strlen( md2_test_str[i] ), md2sum ) != 0 )
+            goto fail;
 
         if( memcmp( md2sum, md2_test_sum[i], 16 ) != 0 )
-        {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
-        }
+            goto fail;
 
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
@@ -281,6 +306,12 @@ int mbedtls_md2_self_test( int verbose )
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( 1 );
 }
 
 #endif /* MBEDTLS_SELF_TEST */