On Wed, Aug 14, 2019, 23:23 Maxim Levitsky wrote:
> While there are other places where these are still stored in memory,
> this is still one less key material area that can be sniffed with
> various side channel attacks
>
>
>
> Signed-off-by: Maxim Levitsky
> ---
> crypto/block-luks.c | 52 ++---
> 1 file changed, 44 insertions(+), 8 deletions(-)
>
> diff --git a/crypto/block-luks.c b/crypto/block-luks.c
> index e1a4df94b7..336e633df4 100644
> --- a/crypto/block-luks.c
> +++ b/crypto/block-luks.c
> @@ -1023,8 +1023,18 @@ qcrypto_block_luks_load_key(QCryptoBlock *block,
> cleanup:
> qcrypto_ivgen_free(ivgen);
> qcrypto_cipher_free(cipher);
> -g_free(splitkey);
> -g_free(possiblekey);
> +
> +if (splitkey) {
> +memset(splitkey, 0, splitkeylen);
>
I think we need memset_s() or similar replacement, see
https://www.cryptologie.net/article/419/zeroing-memory-compiler-optimizations-and-memset_s/
+g_free(splitkey);
> +}
> +
> +if (possiblekey) {
> +memset(possiblekey, 0, masterkeylen(luks));
> +g_free(possiblekey);
> +
> +}
> +
> return ret;
> }
>
> @@ -1161,16 +1171,34 @@ qcrypto_block_luks_open(QCryptoBlock *block,
> block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE;
> block->payload_offset = luks->header.payload_offset *
> block->sector_size;
>
> -g_free(masterkey);
> -g_free(password);
> +if (masterkey) {
> +memset(masterkey, 0, masterkeylen(luks));
> +g_free(masterkey);
> +}
> +
> +if (password) {
> +memset(password, 0, strlen(password));
> +g_free(password);
> +}
> +
> return 0;
>
> fail:
> -g_free(masterkey);
> +
> +if (masterkey) {
> +memset(masterkey, 0, masterkeylen(luks));
> +g_free(masterkey);
> +}
> +
> +if (password) {
> +memset(password, 0, strlen(password));
> +g_free(password);
> +}
> +
> qcrypto_block_free_cipher(block);
> qcrypto_ivgen_free(block->ivgen);
> +
> g_free(luks);
> -g_free(password);
> return ret;
> }
>
> @@ -1459,7 +1487,10 @@ qcrypto_block_luks_create(QCryptoBlock *block,
>
> memset(masterkey, 0, luks->header.key_bytes);
> g_free(masterkey);
> +
> +memset(password, 0, strlen(password));
> g_free(password);
> +
> g_free(cipher_mode_spec);
>
> return 0;
> @@ -1467,9 +1498,14 @@ qcrypto_block_luks_create(QCryptoBlock *block,
> error:
> if (masterkey) {
> memset(masterkey, 0, luks->header.key_bytes);
> +g_free(masterkey);
> }
> -g_free(masterkey);
> -g_free(password);
> +
> +if (password) {
> +memset(password, 0, strlen(password));
> +g_free(password);
> +}
> +
> g_free(cipher_mode_spec);
>
> qcrypto_block_free_cipher(block);
> --
> 2.17.2
>
>
>
