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* [PATCH] drbd: Use struct_group() to zero algs
@ 2021-11-18 20:37 Kees Cook
  2021-12-13 23:28 ` Gustavo A. R. Silva
  2021-12-13 23:31 ` Jens Axboe
  0 siblings, 2 replies; 3+ messages in thread
From: Kees Cook @ 2021-11-18 20:37 UTC (permalink / raw)
  To: Philipp Reisner
  Cc: Kees Cook, Lars Ellenberg, Jens Axboe, linux-kernel, drbd-dev,
	linux-block, linux-hardening

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>
---
 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 53ba2dddba6e..feac72e323bd 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 dea59c92ecc1..a882b65ab5d2 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 1f740e42e457..6df2539e215b 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)
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] drbd: Use struct_group() to zero algs
  2021-11-18 20:37 [PATCH] drbd: Use struct_group() to zero algs Kees Cook
@ 2021-12-13 23:28 ` Gustavo A. R. Silva
  2021-12-13 23:31 ` Jens Axboe
  1 sibling, 0 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2021-12-13 23:28 UTC (permalink / raw)
  To: Kees Cook
  Cc: Philipp Reisner, Lars Ellenberg, Jens Axboe, linux-kernel,
	drbd-dev, linux-block, linux-hardening, Gustavo A. R. Silva

On Thu, Nov 18, 2021 at 12:37:12PM -0800, Kees Cook wrote:
> 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>

Thanks
--
Gustavo

> ---
>  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 53ba2dddba6e..feac72e323bd 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 dea59c92ecc1..a882b65ab5d2 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 1f740e42e457..6df2539e215b 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)
> -- 
> 2.30.2
> 
> 
> 
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] drbd: Use struct_group() to zero algs
  2021-11-18 20:37 [PATCH] drbd: Use struct_group() to zero algs Kees Cook
  2021-12-13 23:28 ` Gustavo A. R. Silva
@ 2021-12-13 23:31 ` Jens Axboe
  1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2021-12-13 23:31 UTC (permalink / raw)
  To: Philipp Reisner, Kees Cook
  Cc: drbd-dev, linux-block, linux-kernel, linux-hardening, Lars Ellenberg

On Thu, 18 Nov 2021 12:37:12 -0800, Kees Cook wrote:
> 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.
> 
> [...]

Applied, thanks!

[1/1] drbd: Use struct_group() to zero algs
      commit: 52a0cab35c568f896067641d8e07f798341954f5

Best regards,
-- 
Jens Axboe



^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-13 23:31 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-11-18 20:37 [PATCH] drbd: Use struct_group() to zero algs Kees Cook
2021-12-13 23:28 ` Gustavo A. R. Silva
2021-12-13 23:31 ` Jens Axboe

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