Wipe stack buffers in block_cipher_df
This is a partial backport of
1b3649906261dfaafcc5b8750279a0012c1c604a (only for the buffer wiping).
Other wiping calls were previously added as backports of
"CTR_DRBG: clean stack
buffers" (d9aa84dc0d42dcb5e23ba2bb47ce39592193b8f1). This completes
the backporting of stack buffer wiping from the development branch.
diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c
index c023c69..d388848 100644
--- a/library/ctr_drbg.c
+++ b/library/ctr_drbg.c
@@ -226,6 +226,10 @@
mbedtls_aes_free( &aes_ctx );
+ mbedtls_zeroize( buf, sizeof( buf ) );
+ mbedtls_zeroize( tmp, sizeof( tmp ) );
+ mbedtls_zeroize( key, sizeof( key ) );
+ mbedtls_zeroize( chain, sizeof( chain ) );
return( 0 );
}