Squashed commit upgrading to mbedtls-2.28.1

Squash merging branch import/mbedtls-2.28.1

 ebf1f6a58089 ("libmbedtls: compile new files added with 2.28.1")
 3ffb51b58a54 ("libmbedtls: add SM2 curve")
 c425755720b4 ("libmbedtls: mbedtls_mpi_exp_mod(): optimize mempool usage")
 23493c822a82 ("libmbedtls: mbedtls_mpi_exp_mod(): reduce stack usage")
 dcdca2348dff ("libmbedtls: mbedtls_mpi_exp_mod() initialize W")
 dc2994976958 ("libmbedtls: fix no CRT issue")
 c6628873b281 ("libmbedtls: add interfaces in mbedtls for context memory operation")
 8acd202d3e55 ("libmedtls: mpi_miller_rabin: increase count limit")
 37284e28d5d9 ("libmbedtls: add mbedtls_mpi_init_mempool()")
 b499a75f29f3 ("libmbedtls: make mbedtls_mpi_mont*() available")
 2080a8c96a5d ("mbedtls: configure mbedtls to reach for config")
 e0858334327a ("mbedtls: remove default include/mbedtls/config.h")
 dd9688e6b8ce ("Import mbedtls-2.28.1")

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/nist_kw.c b/lib/libmbedtls/mbedtls/library/nist_kw.c
index 5054ca2..1aea0b6 100644
--- a/lib/libmbedtls/mbedtls/library/nist_kw.c
+++ b/lib/libmbedtls/mbedtls/library/nist_kw.c
@@ -34,6 +34,7 @@
 #include "mbedtls/nist_kw.h"
 #include "mbedtls/platform_util.h"
 #include "mbedtls/error.h"
+#include "mbedtls/constant_time.h"
 
 #include <stdint.h>
 #include <string.h>
@@ -52,51 +53,11 @@
 #define KW_SEMIBLOCK_LENGTH    8
 #define MIN_SEMIBLOCKS_COUNT   3
 
-/* constant-time buffer comparison */
-static inline unsigned char mbedtls_nist_kw_safer_memcmp( const void *a, const void *b, size_t n )
-{
-    size_t i;
-    volatile const unsigned char *A = (volatile const unsigned char *) a;
-    volatile const unsigned char *B = (volatile const unsigned char *) b;
-    volatile unsigned char diff = 0;
-
-    for( i = 0; i < n; i++ )
-    {
-        /* Read volatile data in order before computing diff.
-         * This avoids IAR compiler warning:
-         * 'the order of volatile accesses is undefined ..' */
-        unsigned char x = A[i], y = B[i];
-        diff |= x ^ y;
-    }
-
-    return( diff );
-}
-
 /*! The 64-bit default integrity check value (ICV) for KW mode. */
 static const unsigned char NIST_KW_ICV1[] = {0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6};
 /*! The 32-bit default integrity check value (ICV) for KWP mode. */
 static const  unsigned char NIST_KW_ICV2[] = {0xA6, 0x59, 0x59, 0xA6};
 
-#ifndef GET_UINT32_BE
-#define GET_UINT32_BE(n,b,i)                            \
-do {                                                    \
-    (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
-        | ( (uint32_t) (b)[(i) + 1] << 16 )             \
-        | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
-        | ( (uint32_t) (b)[(i) + 3]       );            \
-} while( 0 )
-#endif
-
-#ifndef PUT_UINT32_BE
-#define PUT_UINT32_BE(n,b,i)                            \
-do {                                                    \
-    (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
-    (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
-    (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
-    (b)[(i) + 3] = (unsigned char) ( (n)       );       \
-} while( 0 )
-#endif
-
 /*
  * Initialize context
  */
@@ -243,7 +204,7 @@
         }
 
         memcpy( output, NIST_KW_ICV2, KW_SEMIBLOCK_LENGTH / 2 );
-        PUT_UINT32_BE( ( in_len & 0xffffffff ), output,
+        MBEDTLS_PUT_UINT32_BE( ( in_len & 0xffffffff ), output,
                        KW_SEMIBLOCK_LENGTH / 2 );
 
         memcpy( output + KW_SEMIBLOCK_LENGTH, input, in_len );
@@ -418,7 +379,7 @@
             goto cleanup;
 
         /* Check ICV in "constant-time" */
-        diff = mbedtls_nist_kw_safer_memcmp( NIST_KW_ICV1, A, KW_SEMIBLOCK_LENGTH );
+        diff = mbedtls_ct_memcmp( NIST_KW_ICV1, A, KW_SEMIBLOCK_LENGTH );
 
         if( diff != 0 )
         {
@@ -467,14 +428,14 @@
         }
 
         /* Check ICV in "constant-time" */
-        diff = mbedtls_nist_kw_safer_memcmp( NIST_KW_ICV2, A, KW_SEMIBLOCK_LENGTH / 2 );
+        diff = mbedtls_ct_memcmp( NIST_KW_ICV2, A, KW_SEMIBLOCK_LENGTH / 2 );
 
         if( diff != 0 )
         {
             ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
         }
 
-        GET_UINT32_BE( Plen, A, KW_SEMIBLOCK_LENGTH / 2 );
+        Plen = MBEDTLS_GET_UINT32_BE( A, KW_SEMIBLOCK_LENGTH / 2 );
 
         /*
          * Plen is the length of the plaintext, when the input is valid.