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/cmac.c b/lib/libmbedtls/mbedtls/library/cmac.c
index 253ec99..5d101e1 100644
--- a/lib/libmbedtls/mbedtls/library/cmac.c
+++ b/lib/libmbedtls/mbedtls/library/cmac.c
@@ -1,10 +1,10 @@
-// SPDX-License-Identifier: Apache-2.0
 /**
  * \file cmac.c
  *
  * \brief NIST SP800-38B compliant CMAC implementation for AES and 3DES
  *
  *  Copyright (C) 2006-2016, 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.
@@ -49,6 +49,7 @@
 #if defined(MBEDTLS_CMAC_C)
 
 #include "mbedtls/cmac.h"
+#include "mbedtls/platform_util.h"
 
 #include <string.h>
 
@@ -65,10 +66,7 @@
 #endif /* MBEDTLS_SELF_TEST */
 #endif /* MBEDTLS_PLATFORM_C */
 
-/* Implementation that should never be optimized out by the compiler */
-static void mbedtls_zeroize( void *v, size_t n ) {
-    volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
-}
+#if !defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST)
 
 /*
  * Multiplication by u in the Galois field of GF(2^n)
@@ -142,7 +140,7 @@
     unsigned char L[MBEDTLS_CIPHER_BLKSIZE_MAX];
     size_t olen, block_size;
 
-    mbedtls_zeroize( L, sizeof( L ) );
+    mbedtls_platform_zeroize( L, sizeof( L ) );
 
     block_size = ctx->cipher_info->block_size;
 
@@ -160,11 +158,13 @@
         goto exit;
 
 exit:
-    mbedtls_zeroize( L, sizeof( L ) );
+    mbedtls_platform_zeroize( L, sizeof( L ) );
 
     return( ret );
 }
+#endif /* !defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST) */
 
+#if !defined(MBEDTLS_CMAC_ALT)
 static void cmac_xor_block( unsigned char *output, const unsigned char *input1,
                             const unsigned char *input2,
                             const size_t block_size )
@@ -234,7 +234,7 @@
 
     ctx->cmac_ctx = cmac_ctx;
 
-    mbedtls_zeroize( cmac_ctx->state, sizeof( cmac_ctx->state ) );
+    mbedtls_platform_zeroize( cmac_ctx->state, sizeof( cmac_ctx->state ) );
 
     return 0;
 }
@@ -326,8 +326,8 @@
     block_size = ctx->cipher_info->block_size;
     state = cmac_ctx->state;
 
-    mbedtls_zeroize( K1, sizeof( K1 ) );
-    mbedtls_zeroize( K2, sizeof( K2 ) );
+    mbedtls_platform_zeroize( K1, sizeof( K1 ) );
+    mbedtls_platform_zeroize( K2, sizeof( K2 ) );
     cmac_generate_subkeys( ctx, K1, K2 );
 
     last_block = cmac_ctx->unprocessed_block;
@@ -357,14 +357,14 @@
 exit:
     /* Wipe the generated keys on the stack, and any other transients to avoid
      * side channel leakage */
-    mbedtls_zeroize( K1, sizeof( K1 ) );
-    mbedtls_zeroize( K2, sizeof( K2 ) );
+    mbedtls_platform_zeroize( K1, sizeof( K1 ) );
+    mbedtls_platform_zeroize( K2, sizeof( K2 ) );
 
     cmac_ctx->unprocessed_len = 0;
-    mbedtls_zeroize( cmac_ctx->unprocessed_block,
-                     sizeof( cmac_ctx->unprocessed_block ) );
+    mbedtls_platform_zeroize( cmac_ctx->unprocessed_block,
+                              sizeof( cmac_ctx->unprocessed_block ) );
 
-    mbedtls_zeroize( state, MBEDTLS_CIPHER_BLKSIZE_MAX );
+    mbedtls_platform_zeroize( state, MBEDTLS_CIPHER_BLKSIZE_MAX );
     return( ret );
 }
 
@@ -379,10 +379,10 @@
 
     /* Reset the internal state */
     cmac_ctx->unprocessed_len = 0;
-    mbedtls_zeroize( cmac_ctx->unprocessed_block,
-                     sizeof( cmac_ctx->unprocessed_block ) );
-    mbedtls_zeroize( cmac_ctx->state,
-                     sizeof( cmac_ctx->state ) );
+    mbedtls_platform_zeroize( cmac_ctx->unprocessed_block,
+                              sizeof( cmac_ctx->unprocessed_block ) );
+    mbedtls_platform_zeroize( cmac_ctx->state,
+                              sizeof( cmac_ctx->state ) );
 
     return( 0 );
 }
@@ -462,12 +462,14 @@
                                output );
 
 exit:
-    mbedtls_zeroize( int_key, sizeof( int_key ) );
+    mbedtls_platform_zeroize( int_key, sizeof( int_key ) );
 
     return( ret );
 }
 #endif /* MBEDTLS_AES_C */
 
+#endif /* !MBEDTLS_CMAC_ALT */
+
 #if defined(MBEDTLS_SELF_TEST)
 /*
  * CMAC test data for SP800-38B
@@ -765,7 +767,7 @@
                               int block_size,
                               int num_tests )
 {
-    int i, ret;
+    int i, ret = 0;
     mbedtls_cipher_context_t ctx;
     const mbedtls_cipher_info_t *cipher_info;
     unsigned char K1[MBEDTLS_CIPHER_BLKSIZE_MAX];
@@ -826,6 +828,7 @@
         mbedtls_cipher_free( &ctx );
     }
 
+    ret = 0;
     goto exit;
 
 cleanup:
@@ -847,7 +850,7 @@
                                  int num_tests )
 {
     const mbedtls_cipher_info_t *cipher_info;
-    int i, ret;
+    int i, ret = 0;
     unsigned char output[MBEDTLS_CIPHER_BLKSIZE_MAX];
 
     cipher_info = mbedtls_cipher_info_from_type( cipher_type );
@@ -881,6 +884,7 @@
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
     }
+    ret = 0;
 
 exit:
     return( ret );