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/pk.c b/lib/libmbedtls/mbedtls/library/pk.c
index 337aa26..bac685d 100644
--- a/lib/libmbedtls/mbedtls/library/pk.c
+++ b/lib/libmbedtls/mbedtls/library/pk.c
@@ -1,8 +1,8 @@
-// SPDX-License-Identifier: Apache-2.0
 /*
  *  Public Key abstraction layer
  *
  *  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.
@@ -29,7 +29,7 @@
 #include "mbedtls/pk.h"
 #include "mbedtls/pk_internal.h"
 
-#include "mbedtls/bignum.h"
+#include "mbedtls/platform_util.h"
 
 #if defined(MBEDTLS_RSA_C)
 #include "mbedtls/rsa.h"
@@ -42,19 +42,20 @@
 #endif
 
 #include <limits.h>
+#include <stdint.h>
 
-/* 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;
-}
+/* Parameter validation macros based on platform_util.h */
+#define PK_VALIDATE_RET( cond )    \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA )
+#define PK_VALIDATE( cond )        \
+    MBEDTLS_INTERNAL_VALIDATE( cond )
 
 /*
  * Initialise a mbedtls_pk_context
  */
 void mbedtls_pk_init( mbedtls_pk_context *ctx )
 {
-    if( ctx == NULL )
-        return;
+    PK_VALIDATE( ctx != NULL );
 
     ctx->pk_info = NULL;
     ctx->pk_ctx = NULL;
@@ -65,14 +66,44 @@
  */
 void mbedtls_pk_free( mbedtls_pk_context *ctx )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    if( ctx == NULL )
         return;
 
-    ctx->pk_info->ctx_free_func( ctx->pk_ctx );
+    if ( ctx->pk_info != NULL )
+        ctx->pk_info->ctx_free_func( ctx->pk_ctx );
 
-    mbedtls_zeroize( ctx, sizeof( mbedtls_pk_context ) );
+    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pk_context ) );
 }
 
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+/*
+ * Initialize a restart context
+ */
+void mbedtls_pk_restart_init( mbedtls_pk_restart_ctx *ctx )
+{
+    PK_VALIDATE( ctx != NULL );
+    ctx->pk_info = NULL;
+    ctx->rs_ctx = NULL;
+}
+
+/*
+ * Free the components of a restart context
+ */
+void mbedtls_pk_restart_free( mbedtls_pk_restart_ctx *ctx )
+{
+    if( ctx == NULL || ctx->pk_info == NULL ||
+        ctx->pk_info->rs_free_func == NULL )
+    {
+        return;
+    }
+
+    ctx->pk_info->rs_free_func( ctx->rs_ctx );
+
+    ctx->pk_info = NULL;
+    ctx->rs_ctx = NULL;
+}
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
 /*
  * Get pk_info structure from type
  */
@@ -104,7 +135,8 @@
  */
 int mbedtls_pk_setup( mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info )
 {
-    if( ctx == NULL || info == NULL || ctx->pk_info != NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( info == NULL || ctx->pk_info != NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
@@ -127,7 +159,8 @@
     mbedtls_rsa_alt_context *rsa_alt;
     const mbedtls_pk_info_t *info = &mbedtls_rsa_alt_info;
 
-    if( ctx == NULL || ctx->pk_info != NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( ctx->pk_info != NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
@@ -151,7 +184,9 @@
  */
 int mbedtls_pk_can_do( const mbedtls_pk_context *ctx, mbedtls_pk_type_t type )
 {
-    /* null or NONE context can't do anything */
+    /* A context with null pk_info is not set up yet and can't do anything.
+     * For backward compatibility, also accept NULL instead of a context
+     * pointer. */
     if( ctx == NULL || ctx->pk_info == NULL )
         return( 0 );
 
@@ -175,6 +210,78 @@
     return( 0 );
 }
 
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+/*
+ * Helper to set up a restart context if needed
+ */
+static int pk_restart_setup( mbedtls_pk_restart_ctx *ctx,
+                             const mbedtls_pk_info_t *info )
+{
+    /* Don't do anything if already set up or invalid */
+    if( ctx == NULL || ctx->pk_info != NULL )
+        return( 0 );
+
+    /* Should never happen when we're called */
+    if( info->rs_alloc_func == NULL || info->rs_free_func == NULL )
+        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+    if( ( ctx->rs_ctx = info->rs_alloc_func() ) == NULL )
+        return( MBEDTLS_ERR_PK_ALLOC_FAILED );
+
+    ctx->pk_info = info;
+
+    return( 0 );
+}
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
+/*
+ * Verify a signature (restartable)
+ */
+int mbedtls_pk_verify_restartable( mbedtls_pk_context *ctx,
+               mbedtls_md_type_t md_alg,
+               const unsigned char *hash, size_t hash_len,
+               const unsigned char *sig, size_t sig_len,
+               mbedtls_pk_restart_ctx *rs_ctx )
+{
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
+                     hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL ||
+        pk_hashlen_helper( md_alg, &hash_len ) != 0 )
+        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+    /* optimization: use non-restartable version if restart disabled */
+    if( rs_ctx != NULL &&
+        mbedtls_ecp_restart_is_enabled() &&
+        ctx->pk_info->verify_rs_func != NULL )
+    {
+        int ret;
+
+        if( ( ret = pk_restart_setup( rs_ctx, ctx->pk_info ) ) != 0 )
+            return( ret );
+
+        ret = ctx->pk_info->verify_rs_func( ctx->pk_ctx,
+                   md_alg, hash, hash_len, sig, sig_len, rs_ctx->rs_ctx );
+
+        if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
+            mbedtls_pk_restart_free( rs_ctx );
+
+        return( ret );
+    }
+#else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+    (void) rs_ctx;
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
+    if( ctx->pk_info->verify_func == NULL )
+        return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
+
+    return( ctx->pk_info->verify_func( ctx->pk_ctx, md_alg, hash, hash_len,
+                                       sig, sig_len ) );
+}
+
 /*
  * Verify a signature
  */
@@ -182,15 +289,8 @@
                const unsigned char *hash, size_t hash_len,
                const unsigned char *sig, size_t sig_len )
 {
-    if( ctx == NULL || ctx->pk_info == NULL ||
-        pk_hashlen_helper( md_alg, &hash_len ) != 0 )
-        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
-
-    if( ctx->pk_info->verify_func == NULL )
-        return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
-
-    return( ctx->pk_info->verify_func( ctx->pk_ctx, md_alg, hash, hash_len,
-                                       sig, sig_len ) );
+    return( mbedtls_pk_verify_restartable( ctx, md_alg, hash, hash_len,
+                                           sig, sig_len, NULL ) );
 }
 
 /*
@@ -201,7 +301,12 @@
                    const unsigned char *hash, size_t hash_len,
                    const unsigned char *sig, size_t sig_len )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
+                     hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ! mbedtls_pk_can_do( ctx, type ) )
@@ -213,10 +318,10 @@
         int ret;
         const mbedtls_pk_rsassa_pss_options *pss_opts;
 
-#if defined(MBEDTLS_HAVE_INT64)
+#if SIZE_MAX > UINT_MAX
         if( md_alg == MBEDTLS_MD_NONE && UINT_MAX < hash_len )
             return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
-#endif /* MBEDTLS_HAVE_INT64 */
+#endif /* SIZE_MAX > UINT_MAX */
 
         if( options == NULL )
             return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
@@ -252,6 +357,55 @@
 }
 
 /*
+ * Make a signature (restartable)
+ */
+int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx,
+             mbedtls_md_type_t md_alg,
+             const unsigned char *hash, size_t hash_len,
+             unsigned char *sig, size_t *sig_len,
+             int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+             mbedtls_pk_restart_ctx *rs_ctx )
+{
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
+                     hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL ||
+        pk_hashlen_helper( md_alg, &hash_len ) != 0 )
+        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
+    /* optimization: use non-restartable version if restart disabled */
+    if( rs_ctx != NULL &&
+        mbedtls_ecp_restart_is_enabled() &&
+        ctx->pk_info->sign_rs_func != NULL )
+    {
+        int ret;
+
+        if( ( ret = pk_restart_setup( rs_ctx, ctx->pk_info ) ) != 0 )
+            return( ret );
+
+        ret = ctx->pk_info->sign_rs_func( ctx->pk_ctx, md_alg,
+                hash, hash_len, sig, sig_len, f_rng, p_rng, rs_ctx->rs_ctx );
+
+        if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
+            mbedtls_pk_restart_free( rs_ctx );
+
+        return( ret );
+    }
+#else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+    (void) rs_ctx;
+#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
+
+    if( ctx->pk_info->sign_func == NULL )
+        return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
+
+    return( ctx->pk_info->sign_func( ctx->pk_ctx, md_alg, hash, hash_len,
+                                     sig, sig_len, f_rng, p_rng ) );
+}
+
+/*
  * Make a signature
  */
 int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
@@ -259,15 +413,8 @@
              unsigned char *sig, size_t *sig_len,
              int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    if( ctx == NULL || ctx->pk_info == NULL ||
-        pk_hashlen_helper( md_alg, &hash_len ) != 0 )
-        return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
-
-    if( ctx->pk_info->sign_func == NULL )
-        return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
-
-    return( ctx->pk_info->sign_func( ctx->pk_ctx, md_alg, hash, hash_len,
-                                     sig, sig_len, f_rng, p_rng ) );
+    return( mbedtls_pk_sign_restartable( ctx, md_alg, hash, hash_len,
+                                         sig, sig_len, f_rng, p_rng, NULL ) );
 }
 
 /*
@@ -278,7 +425,12 @@
                 unsigned char *output, size_t *olen, size_t osize,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( input != NULL || ilen == 0 );
+    PK_VALIDATE_RET( output != NULL || osize == 0 );
+    PK_VALIDATE_RET( olen != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->decrypt_func == NULL )
@@ -296,7 +448,12 @@
                 unsigned char *output, size_t *olen, size_t osize,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( input != NULL || ilen == 0 );
+    PK_VALIDATE_RET( output != NULL || osize == 0 );
+    PK_VALIDATE_RET( olen != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->encrypt_func == NULL )
@@ -311,8 +468,11 @@
  */
 int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv )
 {
-    if( pub == NULL || pub->pk_info == NULL ||
-        prv == NULL || prv->pk_info == NULL ||
+    PK_VALIDATE_RET( pub != NULL );
+    PK_VALIDATE_RET( prv != NULL );
+
+    if( pub->pk_info == NULL ||
+        prv->pk_info == NULL ||
         prv->pk_info->check_pair_func == NULL )
     {
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
@@ -337,6 +497,8 @@
  */
 size_t mbedtls_pk_get_bitlen( const mbedtls_pk_context *ctx )
 {
+    /* For backward compatibility, accept NULL or a context that
+     * isn't set up yet, and return a fake value that should be safe. */
     if( ctx == NULL || ctx->pk_info == NULL )
         return( 0 );
 
@@ -348,7 +510,8 @@
  */
 int mbedtls_pk_debug( const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->debug_func == NULL )