[PATCH v2] mwl8k: Avoid memcpy() over-reading of mcs.rx_mask

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally reading across neighboring array fields. Use the
sub-structure address directly.

Signed-off-by: Kees Cook <redacted>
---
v2: fix Subject for actual issue
v1: https://lore.kernel.org/lkml/20210616195242.1231287-1-keescook@chromium.org
---
 drivers/net/wireless/marvell/mwl8k.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwl8k.c b/drivers/net/wireless/marvell/mwl8k.c
index 84b32a5f01ee..3bf6571f4149 100644
--- a/drivers/net/wireless/marvell/mwl8k.c
+++ b/drivers/net/wireless/marvell/mwl8k.c

@@ -4552,7 +4552,7 @@ static int mwl8k_cmd_update_stadb_add(struct ieee80211_hw *hw,
 	else
 		rates = sta->supp_rates[NL80211_BAND_5GHZ] << 5;
 	legacy_rate_mask_to_array(p->legacy_rates, rates);
-	memcpy(p->ht_rates, sta->ht_cap.mcs.rx_mask, 16);
+	memcpy(p->ht_rates, &sta->ht_cap.mcs, 16);
 	p->interop = 1;
 	p->amsdu_enabled = 0;
 

@@ -5034,7 +5034,7 @@ mwl8k_bss_info_changed_sta(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			ap_legacy_rates =
 				ap->supp_rates[NL80211_BAND_5GHZ] << 5;
 		}
-		memcpy(ap_mcs_rates, ap->ht_cap.mcs.rx_mask, 16);
+		memcpy(ap_mcs_rates, &ap->ht_cap.mcs, 16);
 
 		rcu_read_unlock();
 

-- 
2.25.1

Kees Cook [off-list ref] wrote:

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally reading across neighboring array fields. Use the
sub-structure address directly.

Signed-off-by: Kees Cook <redacted>

Patch applied to wireless-drivers-next.git, thanks.

3f26f7665c5d mwl8k: Avoid memcpy() over-reading of mcs.rx_mask

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210617041431.2168953-1-keescook@chromium.org/

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