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/pkparse.c b/lib/libmbedtls/mbedtls/library/pkparse.c
index 3222ca2..ea5c6b6 100644
--- a/lib/libmbedtls/mbedtls/library/pkparse.c
+++ b/lib/libmbedtls/mbedtls/library/pkparse.c
@@ -474,7 +474,7 @@
     }
 
     /*
-     * grp may already be initilialized; if so, make sure IDs match
+     * grp may already be initialized; if so, make sure IDs match
      */
     if( grp->id != MBEDTLS_ECP_DP_NONE && grp->id != grp_id )
         return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT );
@@ -807,7 +807,7 @@
        goto cleanup;
 
 #else
-    /* Verify existance of the CRT params */
+    /* Verify existence of the CRT params */
     if( ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||
         ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 ||
         ( ret = asn1_get_nonzero_mpi( &p, end, &T ) ) != 0 )
@@ -1380,8 +1380,11 @@
     }
 #endif /* MBEDTLS_PKCS12_C || MBEDTLS_PKCS5_C */
 
-    if( ( ret = pk_parse_key_pkcs8_unencrypted_der( pk, key, keylen ) ) == 0 )
+    ret = pk_parse_key_pkcs8_unencrypted_der( pk, key, keylen );
+    if( ret == 0 )
+    {
         return( 0 );
+    }
 
     mbedtls_pk_free( pk );
     mbedtls_pk_init( pk );
@@ -1460,10 +1463,16 @@
     {
         p = pem.buf;
         if( ( pk_info = mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) ) == NULL )
+        {
+            mbedtls_pem_free( &pem );
             return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );
+        }
 
         if( ( ret = mbedtls_pk_setup( ctx, pk_info ) ) != 0 )
+        {
+            mbedtls_pem_free( &pem );
             return( ret );
+        }
 
         if ( ( ret = pk_get_rsapubkey( &p, p + pem.buflen, mbedtls_pk_rsa( *ctx ) ) ) != 0 )
             mbedtls_pk_free( ctx );