drbd: Use struct_group() to zero algs

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add a struct_group() for the algs so that memset() can correctly reason
about the size.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20211118203712.1288866-1-keescook@chromium.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Kees Cook 2021-11-18 12:37:12 -08:00 committed by Jens Axboe
parent 322c4293ec
commit 52a0cab35c
3 changed files with 8 additions and 4 deletions

View File

@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device)
cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
/* initialize verify_alg and csums_alg */
memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
memset(&p->algs, 0, sizeof(p->algs));
if (get_ldev(peer_device->device)) {
dc = rcu_dereference(peer_device->device->ldev->disk_conf);

View File

@ -283,8 +283,10 @@ struct p_rs_param_89 {
struct p_rs_param_95 {
u32 resync_rate;
struct_group(algs,
char verify_alg[SHARED_SECRET_MAX];
char csums_alg[SHARED_SECRET_MAX];
);
u32 c_plan_ahead;
u32 c_delay_target;
u32 c_fill_target;

View File

@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i
/* initialize verify_alg and csums_alg */
p = pi->data;
memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
memset(&p->algs, 0, sizeof(p->algs));
err = drbd_recv_all(peer_device->connection, p, header_size);
if (err)