From 52a0cab35c568f896067641d8e07f798341954f5 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 18 Nov 2021 12:37:12 -0800 Subject: [PATCH] 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 Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20211118203712.1288866-1-keescook@chromium.org Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_main.c | 3 ++- drivers/block/drbd/drbd_protocol.h | 6 ++++-- drivers/block/drbd/drbd_receiver.c | 3 ++- 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 07b3c60..6f45081 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -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); diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h index dea59c9..a882b65 100644 --- a/drivers/block/drbd/drbd_protocol.h +++ b/drivers/block/drbd/drbd_protocol.h @@ -283,8 +283,10 @@ struct p_rs_param_89 { struct p_rs_param_95 { u32 resync_rate; - char verify_alg[SHARED_SECRET_MAX]; - char csums_alg[SHARED_SECRET_MAX]; + 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; diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 1f740e4..6df2539 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -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) -- 2.7.4