[PATCH 10/32] wcn36xx: Use mem_to_flex_dup() with struct wcn36xx_hal_ind_msg

[Kees Cook]

As part of the work to perform bounds checking on all memcpy() uses,
replace the open-coded a deserialization of bytes out of memory into a
trailing flexible array by using a flex_array.h helper to perform the
allocation, bounds checking, and copying.

Cc: Loic Poulain <loic.poulain at linaro.org>
Cc: Kalle Valo <kvalo at kernel.org>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: Eric Dumazet <edumazet at google.com>
Cc: Jakub Kicinski <kuba at kernel.org>
Cc: Paolo Abeni <pabeni at redhat.com>
Cc: wcn36xx at lists.infradead.org
Cc: linux-wireless at vger.kernel.org
Cc: netdev at vger.kernel.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/net/wireless/ath/wcn36xx/smd.c | 8 ++------
 drivers/net/wireless/ath/wcn36xx/smd.h | 4 ++--
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index dc3805609284..106af0a2ffc4 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -3343,7 +3343,7 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	const struct wcn36xx_hal_msg_header *msg_header = buf;
 	struct ieee80211_hw *hw = priv;
 	struct wcn36xx *wcn = hw->priv;
-	struct wcn36xx_hal_ind_msg *msg_ind;
+	struct wcn36xx_hal_ind_msg *msg_ind = NULL;
 	wcn36xx_dbg_dump(WCN36XX_DBG_SMD_DUMP, "SMD <<< ", buf, len);
 
 	switch (msg_header->msg_type) {
@@ -3407,16 +3407,12 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	case WCN36XX_HAL_DELETE_STA_CONTEXT_IND:
 	case WCN36XX_HAL_PRINT_REG_INFO_IND:
 	case WCN36XX_HAL_SCAN_OFFLOAD_IND:
-		msg_ind = kmalloc(struct_size(msg_ind, msg, len), GFP_ATOMIC);
-		if (!msg_ind) {
+		if (mem_to_flex_dup(&msg_ind, buf, len, GFP_ATOMIC)) {
 			wcn36xx_err("Run out of memory while handling SMD_EVENT (%d)\n",
 				    msg_header->msg_type);
 			return -ENOMEM;
 		}
 
-		msg_ind->msg_len = len;
-		memcpy(msg_ind->msg, buf, len);
-
 		spin_lock(&wcn->hal_ind_lock);
 		list_add_tail(&msg_ind->list, &wcn->hal_ind_queue);
 		queue_work(wcn->hal_ind_wq, &wcn->hal_ind_work);
diff --git a/drivers/net/wireless/ath/wcn36xx/smd.h b/drivers/net/wireless/ath/wcn36xx/smd.h
index 3fd598ac2a27..76ecac46f36b 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.h
+++ b/drivers/net/wireless/ath/wcn36xx/smd.h
@@ -46,8 +46,8 @@ struct wcn36xx_fw_msg_status_rsp {
 
 struct wcn36xx_hal_ind_msg {
 	struct list_head list;
-	size_t msg_len;
-	u8 msg[];
+	DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(size_t, msg_len);
+	DECLARE_FLEX_ARRAY_ELEMENTS(u8, msg);
 };
 
 struct wcn36xx;
-- 
2.32.0