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/md5.c b/lib/libmbedtls/mbedtls/library/md5.c
index 7691a30..2a740cd 100644
--- a/lib/libmbedtls/mbedtls/library/md5.c
+++ b/lib/libmbedtls/mbedtls/library/md5.c
@@ -1,8 +1,8 @@
-// SPDX-License-Identifier: Apache-2.0
 /*
  *  RFC 1321 compliant MD5 implementation
  *
  *  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 @@
 #if defined(MBEDTLS_MD5_C)
 
 #include "mbedtls/md5.h"
+#include "mbedtls/platform_util.h"
 
 #include <string.h>
 
@@ -47,11 +48,6 @@
 
 #if !defined(MBEDTLS_MD5_ALT)
 
-/* 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;
-}
-
 /*
  * 32-bit integer manipulation macros (little endian)
  */
@@ -85,7 +81,7 @@
     if( ctx == NULL )
         return;
 
-    mbedtls_zeroize( ctx, sizeof( mbedtls_md5_context ) );
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_md5_context ) );
 }
 
 void mbedtls_md5_clone( mbedtls_md5_context *dst,
@@ -97,7 +93,7 @@
 /*
  * MD5 context setup
  */
-void mbedtls_md5_starts( mbedtls_md5_context *ctx )
+int mbedtls_md5_starts_ret( mbedtls_md5_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -106,10 +102,20 @@
     ctx->state[1] = 0xEFCDAB89;
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
+
+    return( 0 );
 }
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+void mbedtls_md5_starts( mbedtls_md5_context *ctx )
+{
+    mbedtls_md5_starts_ret( ctx );
+}
+#endif
+
 #if !defined(MBEDTLS_MD5_PROCESS_ALT)
-void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_md5_process( mbedtls_md5_context *ctx,
+                                  const unsigned char data[64] )
 {
     uint32_t X[16], A, B, C, D;
 
@@ -230,19 +236,32 @@
     ctx->state[1] += B;
     ctx->state[2] += C;
     ctx->state[3] += D;
+
+    return( 0 );
 }
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+void mbedtls_md5_process( mbedtls_md5_context *ctx,
+                          const unsigned char data[64] )
+{
+    mbedtls_internal_md5_process( ctx, data );
+}
+#endif
 #endif /* !MBEDTLS_MD5_PROCESS_ALT */
 
 /*
  * MD5 process buffer
  */
-void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_md5_update_ret( mbedtls_md5_context *ctx,
+                            const unsigned char *input,
+                            size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -256,7 +275,9 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_md5_process( ctx, ctx->buffer );
+        if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -264,7 +285,9 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_md5_process( ctx, input );
+        if( ( ret = mbedtls_internal_md5_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
@@ -273,60 +296,122 @@
     {
         memcpy( (void *) (ctx->buffer + left), input, ilen );
     }
+
+    return( 0 );
 }
 
-static const unsigned char md5_padding[64] =
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+void mbedtls_md5_update( mbedtls_md5_context *ctx,
+                         const unsigned char *input,
+                         size_t ilen )
 {
- 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-};
+    mbedtls_md5_update_ret( ctx, input, ilen );
+}
+#endif
 
 /*
  * MD5 final digest
  */
-void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] )
+int mbedtls_md5_finish_ret( mbedtls_md5_context *ctx,
+                            unsigned char output[16] )
 {
-    uint32_t last, padn;
+    int ret;
+    uint32_t used;
     uint32_t high, low;
-    unsigned char msglen[8];
 
+    /*
+     * Add padding: 0x80 then 0x00 until 8 bytes remain for the length
+     */
+    used = ctx->total[0] & 0x3F;
+
+    ctx->buffer[used++] = 0x80;
+
+    if( used <= 56 )
+    {
+        /* Enough room for padding + length in current block */
+        memset( ctx->buffer + used, 0, 56 - used );
+    }
+    else
+    {
+        /* We'll need an extra block */
+        memset( ctx->buffer + used, 0, 64 - used );
+
+        if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
+        memset( ctx->buffer, 0, 56 );
+    }
+
+    /*
+     * Add message length
+     */
     high = ( ctx->total[0] >> 29 )
          | ( ctx->total[1] <<  3 );
     low  = ( ctx->total[0] <<  3 );
 
-    PUT_UINT32_LE( low,  msglen, 0 );
-    PUT_UINT32_LE( high, msglen, 4 );
+    PUT_UINT32_LE( low,  ctx->buffer, 56 );
+    PUT_UINT32_LE( high, ctx->buffer, 60 );
 
-    last = ctx->total[0] & 0x3F;
-    padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
+    if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
+        return( ret );
 
-    mbedtls_md5_update( ctx, md5_padding, padn );
-    mbedtls_md5_update( ctx, msglen, 8 );
-
+    /*
+     * Output final state
+     */
     PUT_UINT32_LE( ctx->state[0], output,  0 );
     PUT_UINT32_LE( ctx->state[1], output,  4 );
     PUT_UINT32_LE( ctx->state[2], output,  8 );
     PUT_UINT32_LE( ctx->state[3], output, 12 );
+
+    return( 0 );
 }
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+void mbedtls_md5_finish( mbedtls_md5_context *ctx,
+                         unsigned char output[16] )
+{
+    mbedtls_md5_finish_ret( ctx, output );
+}
+#endif
+
 #endif /* !MBEDTLS_MD5_ALT */
 
 /*
  * output = MD5( input buffer )
  */
-void mbedtls_md5( const unsigned char *input, size_t ilen, unsigned char output[16] )
+int mbedtls_md5_ret( const unsigned char *input,
+                     size_t ilen,
+                     unsigned char output[16] )
 {
+    int ret;
     mbedtls_md5_context ctx;
 
     mbedtls_md5_init( &ctx );
-    mbedtls_md5_starts( &ctx );
-    mbedtls_md5_update( &ctx, input, ilen );
-    mbedtls_md5_finish( &ctx, output );
+
+    if( ( ret = mbedtls_md5_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md5_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md5_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_md5_free( &ctx );
+
+    return( ret );
 }
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+void mbedtls_md5( const unsigned char *input,
+                  size_t ilen,
+                  unsigned char output[16] )
+{
+    mbedtls_md5_ret( input, ilen, output );
+}
+#endif
+
 #if defined(MBEDTLS_SELF_TEST)
 /*
  * RFC 1321 test vectors
@@ -339,11 +424,11 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
-static const int md5_test_buflen[7] =
+static const size_t md5_test_buflen[7] =
 {
     0, 1, 3, 14, 26, 62, 80
 };
@@ -371,7 +456,7 @@
  */
 int mbedtls_md5_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md5sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -379,14 +464,14 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD5 test #%d: ", i + 1 );
 
-        mbedtls_md5( md5_test_buf[i], md5_test_buflen[i], md5sum );
+        ret = mbedtls_md5_ret( md5_test_buf[i], md5_test_buflen[i], md5sum );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( md5sum, md5_test_sum[i], 16 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
+            ret = 1;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -397,6 +482,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */