virtio-crypto: zeroize the key material before free

Common practice with sensitive information (key material, passwords,
etc). Prevents sensitive information from being exposed by accident later in
coredumps, memory disclosure bugs when heap memory is reused, etc.

Sensitive information is sometimes also held in mlocked pages to prevent
it being swapped to disk but that's not being done here.

Let's zeroize the memory of CryptoDevBackendSymOpInfo structure pointed
for key material security.

[Thanks to Stefan for help with crafting the commit message]

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Gonglei 2016-12-22 11:01:28 +08:00 committed by Michael S. Tsirkin
parent ef69d971cd
commit 02ed3e7c16

View File

@ -337,7 +337,18 @@ static void virtio_crypto_free_request(VirtIOCryptoReq *req)
{
if (req) {
if (req->flags == CRYPTODEV_BACKEND_ALG_SYM) {
g_free(req->u.sym_op_info);
size_t max_len;
CryptoDevBackendSymOpInfo *op_info = req->u.sym_op_info;
max_len = op_info->iv_len +
op_info->aad_len +
op_info->src_len +
op_info->dst_len +
op_info->digest_result_len;
/* Zeroize and free request data structure */
memset(op_info, 0, sizeof(*op_info) + max_len);
g_free(op_info);
}
g_free(req);
}