Import mbedtls-2.16.0

Imports mbedTLS 2.16.0 from https://github.com/ARMmbed/mbedtls.git
commit fb1972db23da ("Merge pull request #544 from ARMmbed/version-2.16")
(tag mbedtls-2.16.0).

Certain files will never be needed and are thus removed (reducing number
of lines to almost 50%):
rm -f circle.yml CMakeLists.txt DartConfiguration.tcl Makefile
rm -f .gitignore .travis.yml .pylint
rm -f include/.gitignore include/CMakeLists.txt library/.gitignore
rm -f library/CMakeLists.txt library/Makefile
rm -rf .git .github doxygen configs programs scripts tests visualc yotta

This is a complete overwrite of previous code so earlier changes in the
branch import/mbedtls-2.6.1 will be added on top of this commit to bring
the changes forward.

Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/md.c b/lib/libmbedtls/mbedtls/library/md.c
index fca82ba..303cdcb 100644
--- a/lib/libmbedtls/mbedtls/library/md.c
+++ b/lib/libmbedtls/mbedtls/library/md.c
@@ -1,4 +1,3 @@
-// SPDX-License-Identifier: Apache-2.0
 /**
  * \file mbedtls_md.c
  *
@@ -7,6 +6,7 @@
  * \author Adriaan de Jong <dejong@fox-it.com>
  *
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
  *
  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  *  not use this file except in compliance with the License.
@@ -33,6 +33,7 @@
 
 #include "mbedtls/md.h"
 #include "mbedtls/md_internal.h"
+#include "mbedtls/platform_util.h"
 
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
@@ -48,11 +49,6 @@
 #include <stdio.h>
 #endif
 
-/* Implementation that should never be optimized out by the compiler */
-static void mbedtls_zeroize( void *v, size_t n ) {
-    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
-}
-
 /*
  * Reminder: update profiles in x509_crt.c when adding a new hash!
  */
@@ -193,11 +189,12 @@
 
     if( ctx->hmac_ctx != NULL )
     {
-        mbedtls_zeroize( ctx->hmac_ctx, 2 * ctx->md_info->block_size );
+        mbedtls_platform_zeroize( ctx->hmac_ctx,
+                                  2 * ctx->md_info->block_size );
         mbedtls_free( ctx->hmac_ctx );
     }
 
-    mbedtls_zeroize( ctx, sizeof( mbedtls_md_context_t ) );
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_md_context_t ) );
 }
 
 int mbedtls_md_clone( mbedtls_md_context_t *dst,
@@ -250,9 +247,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-
-    return( 0 );
+    return( ctx->md_info->starts_func( ctx->md_ctx ) );
 }
 
 int mbedtls_md_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
@@ -260,9 +255,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->update_func( ctx->md_ctx, input, ilen );
-
-    return( 0 );
+    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
 }
 
 int mbedtls_md_finish( mbedtls_md_context_t *ctx, unsigned char *output )
@@ -270,9 +263,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->finish_func( ctx->md_ctx, output );
-
-    return( 0 );
+    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
 }
 
 int mbedtls_md( const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen,
@@ -281,9 +272,7 @@
     if( md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    md_info->digest_func( input, ilen, output );
-
-    return( 0 );
+    return( md_info->digest_func( input, ilen, output ) );
 }
 
 #if defined(MBEDTLS_FS_IO)
@@ -306,20 +295,20 @@
     if( ( ret = mbedtls_md_setup( &ctx, md_info, 0 ) ) != 0 )
         goto cleanup;
 
-    md_info->starts_func( ctx.md_ctx );
+    if( ( ret = md_info->starts_func( ctx.md_ctx ) ) != 0 )
+        goto cleanup;
 
     while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
-        md_info->update_func( ctx.md_ctx, buf, n );
+        if( ( ret = md_info->update_func( ctx.md_ctx, buf, n ) ) != 0 )
+            goto cleanup;
 
     if( ferror( f ) != 0 )
-    {
         ret = MBEDTLS_ERR_MD_FILE_IO_ERROR;
-        goto cleanup;
-    }
-
-    md_info->finish_func( ctx.md_ctx, output );
+    else
+        ret = md_info->finish_func( ctx.md_ctx, output );
 
 cleanup:
+    mbedtls_platform_zeroize( buf, sizeof( buf ) );
     fclose( f );
     mbedtls_md_free( &ctx );
 
@@ -329,6 +318,7 @@
 
 int mbedtls_md_hmac_starts( mbedtls_md_context_t *ctx, const unsigned char *key, size_t keylen )
 {
+    int ret;
     unsigned char sum[MBEDTLS_MD_MAX_SIZE];
     unsigned char *ipad, *opad;
     size_t i;
@@ -338,9 +328,12 @@
 
     if( keylen > (size_t) ctx->md_info->block_size )
     {
-        ctx->md_info->starts_func( ctx->md_ctx );
-        ctx->md_info->update_func( ctx->md_ctx, key, keylen );
-        ctx->md_info->finish_func( ctx->md_ctx, sum );
+        if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+            goto cleanup;
+        if( ( ret = ctx->md_info->update_func( ctx->md_ctx, key, keylen ) ) != 0 )
+            goto cleanup;
+        if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, sum ) ) != 0 )
+            goto cleanup;
 
         keylen = ctx->md_info->size;
         key = sum;
@@ -358,12 +351,16 @@
         opad[i] = (unsigned char)( opad[i] ^ key[i] );
     }
 
-    mbedtls_zeroize( sum, sizeof( sum ) );
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        goto cleanup;
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, ipad,
+                                           ctx->md_info->block_size ) ) != 0 )
+        goto cleanup;
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, ipad, ctx->md_info->block_size );
+cleanup:
+    mbedtls_platform_zeroize( sum, sizeof( sum ) );
 
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_md_hmac_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
@@ -371,13 +368,12 @@
     if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->update_func( ctx->md_ctx, input, ilen );
-
-    return( 0 );
+    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
 }
 
 int mbedtls_md_hmac_finish( mbedtls_md_context_t *ctx, unsigned char *output )
 {
+    int ret;
     unsigned char tmp[MBEDTLS_MD_MAX_SIZE];
     unsigned char *opad;
 
@@ -386,17 +382,22 @@
 
     opad = (unsigned char *) ctx->hmac_ctx + ctx->md_info->block_size;
 
-    ctx->md_info->finish_func( ctx->md_ctx, tmp );
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, opad, ctx->md_info->block_size );
-    ctx->md_info->update_func( ctx->md_ctx, tmp, ctx->md_info->size );
-    ctx->md_info->finish_func( ctx->md_ctx, output );
-
-    return( 0 );
+    if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, tmp ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, opad,
+                                           ctx->md_info->block_size ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, tmp,
+                                           ctx->md_info->size ) ) != 0 )
+        return( ret );
+    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
 }
 
 int mbedtls_md_hmac_reset( mbedtls_md_context_t *ctx )
 {
+    int ret;
     unsigned char *ipad;
 
     if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
@@ -404,15 +405,16 @@
 
     ipad = (unsigned char *) ctx->hmac_ctx;
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, ipad, ctx->md_info->block_size );
-
-    return( 0 );
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        return( ret );
+    return( ctx->md_info->update_func( ctx->md_ctx, ipad,
+                                       ctx->md_info->block_size ) );
 }
 
-int mbedtls_md_hmac( const mbedtls_md_info_t *md_info, const unsigned char *key, size_t keylen,
-                const unsigned char *input, size_t ilen,
-                unsigned char *output )
+int mbedtls_md_hmac( const mbedtls_md_info_t *md_info,
+                     const unsigned char *key, size_t keylen,
+                     const unsigned char *input, size_t ilen,
+                     unsigned char *output )
 {
     mbedtls_md_context_t ctx;
     int ret;
@@ -423,15 +425,19 @@
     mbedtls_md_init( &ctx );
 
     if( ( ret = mbedtls_md_setup( &ctx, md_info, 1 ) ) != 0 )
-        return( ret );
+        goto cleanup;
 
-    mbedtls_md_hmac_starts( &ctx, key, keylen );
-    mbedtls_md_hmac_update( &ctx, input, ilen );
-    mbedtls_md_hmac_finish( &ctx, output );
+    if( ( ret = mbedtls_md_hmac_starts( &ctx, key, keylen ) ) != 0 )
+        goto cleanup;
+    if( ( ret = mbedtls_md_hmac_update( &ctx, input, ilen ) ) != 0 )
+        goto cleanup;
+    if( ( ret = mbedtls_md_hmac_finish( &ctx, output ) ) != 0 )
+        goto cleanup;
 
+cleanup:
     mbedtls_md_free( &ctx );
 
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_md_process( mbedtls_md_context_t *ctx, const unsigned char *data )
@@ -439,9 +445,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->process_func( ctx->md_ctx, data );
-
-    return( 0 );
+    return( ctx->md_info->process_func( ctx->md_ctx, data ) );
 }
 
 unsigned char mbedtls_md_get_size( const mbedtls_md_info_t *md_info )