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/pem.c b/lib/libmbedtls/mbedtls/library/pem.c
index 2f10e50..897c8a0 100644
--- a/lib/libmbedtls/mbedtls/library/pem.c
+++ b/lib/libmbedtls/mbedtls/library/pem.c
@@ -1,8 +1,8 @@
-// SPDX-License-Identifier: Apache-2.0
 /*
  *  Privacy Enhanced Mail (PEM) decoding
  *
  *  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/aes.h"
 #include "mbedtls/md5.h"
 #include "mbedtls/cipher.h"
+#include "mbedtls/platform_util.h"
 
 #include <string.h>
 
@@ -45,11 +46,6 @@
 #endif
 
 #if defined(MBEDTLS_PEM_PARSE_C)
-/* 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;
-}
-
 void mbedtls_pem_init( mbedtls_pem_context *ctx )
 {
     memset( ctx, 0, sizeof( mbedtls_pem_context ) );
@@ -82,31 +78,33 @@
     return( 0 );
 }
 
-static void pem_pbkdf1( unsigned char *key, size_t keylen,
-                        unsigned char *iv,
-                        const unsigned char *pwd, size_t pwdlen )
+static int pem_pbkdf1( unsigned char *key, size_t keylen,
+                       unsigned char *iv,
+                       const unsigned char *pwd, size_t pwdlen )
 {
     mbedtls_md5_context md5_ctx;
     unsigned char md5sum[16];
     size_t use_len;
+    int ret;
 
     mbedtls_md5_init( &md5_ctx );
 
     /*
      * key[ 0..15] = MD5(pwd || IV)
      */
-    mbedtls_md5_starts( &md5_ctx );
-    mbedtls_md5_update( &md5_ctx, pwd, pwdlen );
-    mbedtls_md5_update( &md5_ctx, iv,  8 );
-    mbedtls_md5_finish( &md5_ctx, md5sum );
+    if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv,  8 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
+        goto exit;
 
     if( keylen <= 16 )
     {
         memcpy( key, md5sum, keylen );
-
-        mbedtls_md5_free( &md5_ctx );
-        mbedtls_zeroize( md5sum, 16 );
-        return;
+        goto exit;
     }
 
     memcpy( key, md5sum, 16 );
@@ -114,11 +112,16 @@
     /*
      * key[16..23] = MD5(key[ 0..15] || pwd || IV])
      */
-    mbedtls_md5_starts( &md5_ctx );
-    mbedtls_md5_update( &md5_ctx, md5sum,  16 );
-    mbedtls_md5_update( &md5_ctx, pwd, pwdlen );
-    mbedtls_md5_update( &md5_ctx, iv,  8 );
-    mbedtls_md5_finish( &md5_ctx, md5sum );
+    if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, md5sum, 16 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
+        goto exit;
 
     use_len = 16;
     if( keylen < 32 )
@@ -126,53 +129,68 @@
 
     memcpy( key + 16, md5sum, use_len );
 
+exit:
     mbedtls_md5_free( &md5_ctx );
-    mbedtls_zeroize( md5sum, 16 );
+    mbedtls_platform_zeroize( md5sum, 16 );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_DES_C)
 /*
  * Decrypt with DES-CBC, using PBKDF1 for key derivation
  */
-static void pem_des_decrypt( unsigned char des_iv[8],
-                               unsigned char *buf, size_t buflen,
-                               const unsigned char *pwd, size_t pwdlen )
+static int pem_des_decrypt( unsigned char des_iv[8],
+                            unsigned char *buf, size_t buflen,
+                            const unsigned char *pwd, size_t pwdlen )
 {
     mbedtls_des_context des_ctx;
     unsigned char des_key[8];
+    int ret;
 
     mbedtls_des_init( &des_ctx );
 
-    pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
-    mbedtls_des_setkey_dec( &des_ctx, des_key );
-    mbedtls_des_crypt_cbc( &des_ctx, MBEDTLS_DES_DECRYPT, buflen,
+    if( ( ret = mbedtls_des_setkey_dec( &des_ctx, des_key ) ) != 0 )
+        goto exit;
+    ret = mbedtls_des_crypt_cbc( &des_ctx, MBEDTLS_DES_DECRYPT, buflen,
                      des_iv, buf, buf );
 
+exit:
     mbedtls_des_free( &des_ctx );
-    mbedtls_zeroize( des_key, 8 );
+    mbedtls_platform_zeroize( des_key, 8 );
+
+    return( ret );
 }
 
 /*
  * Decrypt with 3DES-CBC, using PBKDF1 for key derivation
  */
-static void pem_des3_decrypt( unsigned char des3_iv[8],
-                               unsigned char *buf, size_t buflen,
-                               const unsigned char *pwd, size_t pwdlen )
+static int pem_des3_decrypt( unsigned char des3_iv[8],
+                             unsigned char *buf, size_t buflen,
+                             const unsigned char *pwd, size_t pwdlen )
 {
     mbedtls_des3_context des3_ctx;
     unsigned char des3_key[24];
+    int ret;
 
     mbedtls_des3_init( &des3_ctx );
 
-    pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
-    mbedtls_des3_set3key_dec( &des3_ctx, des3_key );
-    mbedtls_des3_crypt_cbc( &des3_ctx, MBEDTLS_DES_DECRYPT, buflen,
+    if( ( ret = mbedtls_des3_set3key_dec( &des3_ctx, des3_key ) ) != 0 )
+        goto exit;
+    ret = mbedtls_des3_crypt_cbc( &des3_ctx, MBEDTLS_DES_DECRYPT, buflen,
                      des3_iv, buf, buf );
 
+exit:
     mbedtls_des3_free( &des3_ctx );
-    mbedtls_zeroize( des3_key, 24 );
+    mbedtls_platform_zeroize( des3_key, 24 );
+
+    return( ret );
 }
 #endif /* MBEDTLS_DES_C */
 
@@ -180,23 +198,29 @@
 /*
  * Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation
  */
-static void pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen,
-                               unsigned char *buf, size_t buflen,
-                               const unsigned char *pwd, size_t pwdlen )
+static int pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen,
+                            unsigned char *buf, size_t buflen,
+                            const unsigned char *pwd, size_t pwdlen )
 {
     mbedtls_aes_context aes_ctx;
     unsigned char aes_key[32];
+    int ret;
 
     mbedtls_aes_init( &aes_ctx );
 
-    pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
-    mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 );
-    mbedtls_aes_crypt_cbc( &aes_ctx, MBEDTLS_AES_DECRYPT, buflen,
+    if( ( ret = mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 ) ) != 0 )
+        goto exit;
+    ret = mbedtls_aes_crypt_cbc( &aes_ctx, MBEDTLS_AES_DECRYPT, buflen,
                      aes_iv, buf, buf );
 
+exit:
     mbedtls_aes_free( &aes_ctx );
-    mbedtls_zeroize( aes_key, keylen );
+    mbedtls_platform_zeroize( aes_key, keylen );
+
+    return( ret );
 }
 #endif /* MBEDTLS_AES_C */
 
@@ -331,6 +355,7 @@
 
     if( ( ret = mbedtls_base64_decode( buf, len, &len, s1, s2 - s1 ) ) != 0 )
     {
+        mbedtls_platform_zeroize( buf, len );
         mbedtls_free( buf );
         return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
     }
@@ -341,38 +366,49 @@
     ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) )
         if( pwd == NULL )
         {
+            mbedtls_platform_zeroize( buf, len );
             mbedtls_free( buf );
             return( MBEDTLS_ERR_PEM_PASSWORD_REQUIRED );
         }
 
+        ret = 0;
+
 #if defined(MBEDTLS_DES_C)
         if( enc_alg == MBEDTLS_CIPHER_DES_EDE3_CBC )
-            pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen );
+            ret = pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen );
         else if( enc_alg == MBEDTLS_CIPHER_DES_CBC )
-            pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen );
+            ret = pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen );
 #endif /* MBEDTLS_DES_C */
 
 #if defined(MBEDTLS_AES_C)
         if( enc_alg == MBEDTLS_CIPHER_AES_128_CBC )
-            pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen );
+            ret = pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen );
         else if( enc_alg == MBEDTLS_CIPHER_AES_192_CBC )
-            pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen );
+            ret = pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen );
         else if( enc_alg == MBEDTLS_CIPHER_AES_256_CBC )
-            pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen );
+            ret = pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen );
 #endif /* MBEDTLS_AES_C */
 
+        if( ret != 0 )
+        {
+            mbedtls_free( buf );
+            return( ret );
+        }
+
         /*
          * The result will be ASN.1 starting with a SEQUENCE tag, with 1 to 3
          * length bytes (allow 4 to be sure) in all known use cases.
          *
-         * Use that as heurisitic to try detecting password mismatchs.
+         * Use that as a heuristic to try to detect password mismatches.
          */
         if( len <= 2 || buf[0] != 0x30 || buf[1] > 0x83 )
         {
+            mbedtls_platform_zeroize( buf, len );
             mbedtls_free( buf );
             return( MBEDTLS_ERR_PEM_PASSWORD_MISMATCH );
         }
 #else
+        mbedtls_platform_zeroize( buf, len );
         mbedtls_free( buf );
         return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE );
 #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC &&
@@ -387,10 +423,14 @@
 
 void mbedtls_pem_free( mbedtls_pem_context *ctx )
 {
-    mbedtls_free( ctx->buf );
+    if ( ctx->buf != NULL )
+    {
+        mbedtls_platform_zeroize( ctx->buf, ctx->buflen );
+        mbedtls_free( ctx->buf );
+    }
     mbedtls_free( ctx->info );
 
-    mbedtls_zeroize( ctx, sizeof( mbedtls_pem_context ) );
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pem_context ) );
 }
 #endif /* MBEDTLS_PEM_PARSE_C */
 
@@ -400,7 +440,7 @@
                       unsigned char *buf, size_t buf_len, size_t *olen )
 {
     int ret;
-    unsigned char *encode_buf, *c, *p = buf;
+    unsigned char *encode_buf = NULL, *c, *p = buf;
     size_t len = 0, use_len, add_len = 0;
 
     mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len );
@@ -412,7 +452,8 @@
         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
     }
 
-    if( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL )
+    if( use_len != 0 &&
+        ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) )
         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 
     if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,