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/pkwrite.c b/lib/libmbedtls/mbedtls/library/pkwrite.c
index 9966f74..8d1da2f 100644
--- a/lib/libmbedtls/mbedtls/library/pkwrite.c
+++ b/lib/libmbedtls/mbedtls/library/pkwrite.c
@@ -1,8 +1,8 @@
-// SPDX-License-Identifier: Apache-2.0
 /*
  *  Public Key layer for writing key files and structures
  *
  *  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.
@@ -30,6 +30,7 @@
 #include "mbedtls/pk.h"
 #include "mbedtls/asn1write.h"
 #include "mbedtls/oid.h"
+#include "mbedtls/platform_util.h"
 
 #include <string.h>
 
@@ -54,6 +55,12 @@
 #define mbedtls_free       free
 #endif
 
+/* 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 )
+
 #if defined(MBEDTLS_RSA_C)
 /*
  *  RSAPublicKey ::= SEQUENCE {
@@ -62,13 +69,31 @@
  *  }
  */
 static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start,
-                                  mbedtls_rsa_context *rsa )
+                                mbedtls_rsa_context *rsa )
 {
     int ret;
     size_t len = 0;
+    mbedtls_mpi T;
 
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( p, start, &rsa->E ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( p, start, &rsa->N ) );
+    mbedtls_mpi_init( &T );
+
+    /* Export E */
+    if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL, NULL, NULL, &T ) ) != 0 ||
+         ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 )
+        goto end_of_export;
+    len += ret;
+
+    /* Export N */
+    if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL, NULL, NULL, NULL ) ) != 0 ||
+         ( ret = mbedtls_asn1_write_mpi( p, start, &T ) ) < 0 )
+        goto end_of_export;
+    len += ret;
+
+end_of_export:
+
+    mbedtls_mpi_free( &T );
+    if( ret < 0 )
+        return( ret );
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED |
@@ -83,7 +108,7 @@
  * EC public key is an EC point
  */
 static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start,
-                                 mbedtls_ecp_keypair *ec )
+                               mbedtls_ecp_keypair *ec )
 {
     int ret;
     size_t len = 0;
@@ -111,7 +136,7 @@
  * }
  */
 static int pk_write_ec_param( unsigned char **p, unsigned char *start,
-                                mbedtls_ecp_keypair *ec )
+                              mbedtls_ecp_keypair *ec )
 {
     int ret;
     size_t len = 0;
@@ -128,11 +153,16 @@
 #endif /* MBEDTLS_ECP_C */
 
 int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start,
-                     const mbedtls_pk_context *key )
+                             const mbedtls_pk_context *key )
 {
     int ret;
     size_t len = 0;
 
+    PK_VALIDATE_RET( p != NULL );
+    PK_VALIDATE_RET( *p != NULL );
+    PK_VALIDATE_RET( start != NULL );
+    PK_VALIDATE_RET( key != NULL );
+
 #if defined(MBEDTLS_RSA_C)
     if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA )
         MBEDTLS_ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, mbedtls_pk_rsa( *key ) ) );
@@ -155,6 +185,11 @@
     size_t len = 0, par_len = 0, oid_len;
     const char *oid;
 
+    PK_VALIDATE_RET( key != NULL );
+    if( size == 0 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+    PK_VALIDATE_RET( buf != NULL );
+
     c = buf + size;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, key ) );
@@ -199,27 +234,92 @@
 int mbedtls_pk_write_key_der( mbedtls_pk_context *key, unsigned char *buf, size_t size )
 {
     int ret;
-    unsigned char *c = buf + size;
+    unsigned char *c;
     size_t len = 0;
 
+    PK_VALIDATE_RET( key != NULL );
+    if( size == 0 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+    PK_VALIDATE_RET( buf != NULL );
+
+    c = buf + size;
+
 #if defined(MBEDTLS_RSA_C)
     if( mbedtls_pk_get_type( key ) == MBEDTLS_PK_RSA )
     {
+        mbedtls_mpi T; /* Temporary holding the exported parameters */
         mbedtls_rsa_context *rsa = mbedtls_pk_rsa( *key );
 
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->QP ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->DQ ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->DP ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->Q ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->P ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->D ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->E ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf, &rsa->N ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) );
+        /*
+         * Export the parameters one after another to avoid simultaneous copies.
+         */
 
+        mbedtls_mpi_init( &T );
+
+        /* Export QP */
+        if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, NULL, &T ) ) != 0 ||
+            ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export DQ */
+        if( ( ret = mbedtls_rsa_export_crt( rsa, NULL, &T, NULL ) ) != 0 ||
+            ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export DP */
+        if( ( ret = mbedtls_rsa_export_crt( rsa, &T, NULL, NULL ) ) != 0 ||
+            ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export Q */
+        if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL,
+                                         &T, NULL, NULL ) ) != 0 ||
+             ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export P */
+        if ( ( ret = mbedtls_rsa_export( rsa, NULL, &T,
+                                         NULL, NULL, NULL ) ) != 0 ||
+             ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export D */
+        if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL,
+                                         NULL, &T, NULL ) ) != 0 ||
+             ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export E */
+        if ( ( ret = mbedtls_rsa_export( rsa, NULL, NULL,
+                                         NULL, NULL, &T ) ) != 0 ||
+             ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+        /* Export N */
+        if ( ( ret = mbedtls_rsa_export( rsa, &T, NULL,
+                                         NULL, NULL, NULL ) ) != 0 ||
+             ( ret = mbedtls_asn1_write_mpi( &c, buf, &T ) ) < 0 )
+            goto end_of_export;
+        len += ret;
+
+    end_of_export:
+
+        mbedtls_mpi_free( &T );
+        if( ret < 0 )
+            return( ret );
+
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 0 ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                    MBEDTLS_ASN1_SEQUENCE ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c,
+                                               buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                               MBEDTLS_ASN1_SEQUENCE ) );
     }
     else
 #endif /* MBEDTLS_RSA_C */
@@ -381,6 +481,9 @@
     unsigned char output_buf[PUB_DER_MAX_BYTES];
     size_t olen = 0;
 
+    PK_VALIDATE_RET( key != NULL );
+    PK_VALIDATE_RET( buf != NULL || size == 0 );
+
     if( ( ret = mbedtls_pk_write_pubkey_der( key, output_buf,
                                      sizeof(output_buf) ) ) < 0 )
     {
@@ -404,6 +507,9 @@
     const char *begin, *end;
     size_t olen = 0;
 
+    PK_VALIDATE_RET( key != NULL );
+    PK_VALIDATE_RET( buf != NULL || size == 0 );
+
     if( ( ret = mbedtls_pk_write_key_der( key, output_buf, sizeof(output_buf) ) ) < 0 )
         return( ret );