[PATCH] wcn36xx: Avoid memset() beyond end of struct field

[PATCH] wcn36xx: Avoid memset() beyond end of struct field

[Kees Cook]

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

Instead of writing past the end of the header to reach the rest of
the body, replace the redundant function with existing macro to wipe
struct contents and set field values. Additionally adjusts macro to add
missing parens.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/net/wireless/ath/wcn36xx/smd.c | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index d0c3a1557e8d..b3bea07d0641 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -445,22 +445,12 @@ static int wcn36xx_smd_send_and_wait(struct wcn36xx *wcn, size_t len)
 	return ret;
 }
 
-static void init_hal_msg(struct wcn36xx_hal_msg_header *hdr,
-			 enum wcn36xx_hal_host_msg_type msg_type,
-			 size_t msg_size)
-{
-	memset(hdr, 0, msg_size + sizeof(*hdr));
-	hdr->msg_type = msg_type;
-	hdr->msg_version = WCN36XX_HAL_MSG_VERSION0;
-	hdr->len = msg_size + sizeof(*hdr);
-}
-
 #define __INIT_HAL_MSG(msg_body, type, version) \
 	do {								\
-		memset(&msg_body, 0, sizeof(msg_body));			\
-		msg_body.header.msg_type = type;			\
-		msg_body.header.msg_version = version;			\
-		msg_body.header.len = sizeof(msg_body);			\
+		memset(&(msg_body), 0, sizeof(msg_body));		\
+		(msg_body).header.msg_type = type;			\
+		(msg_body).header.msg_version = version;		\
+		(msg_body).header.len = sizeof(msg_body);		\
 	} while (0)							\
 
 #define INIT_HAL_MSG(msg_body, type)	\
@@ -2729,8 +2719,7 @@ int wcn36xx_smd_set_mc_list(struct wcn36xx *wcn,
 
 	msg_body = (struct wcn36xx_hal_rcv_flt_pkt_set_mc_list_req_msg *)
 		   wcn->hal_buf;
-	init_hal_msg(&msg_body->header, WCN36XX_HAL_8023_MULTICAST_LIST_REQ,
-		     sizeof(msg_body->mc_addr_list));
+	INIT_HAL_MSG(*msg_body, WCN36XX_HAL_8023_MULTICAST_LIST_REQ);
 
 	/* An empty list means all mc traffic will be received */
 	if (fp)
-- 
2.25.1

Re: [PATCH] wcn36xx: Avoid memset() beyond end of struct field

[Kalle Valo]

Kees Cook <keescook@chromium.org> wrote:

> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memset(), avoid intentionally writing across
> neighboring array fields.
> 
> Instead of writing past the end of the header to reach the rest of
> the body, replace the redundant function with existing macro to wipe
> struct contents and set field values. Additionally adjusts macro to add
> missing parens.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

Patch applied to ath-next branch of ath.git, thanks.

d3a1a18ab034 wcn36xx: Avoid memset() beyond end of struct field

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210617171058.3410494-1-keescook@chromium.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches