[PATCH 39/64] mac80211: Use memset_after() to clear tx status
From: Kees Cook <hidden>
Date: 2021-07-27 21:07:59
Also in:
dri-devel, linux-block, linux-hardening, linux-kbuild, linux-staging, linux-wireless, lkml
Subsystem:
atheros ath generic utilities, carl9170 linux community wireless driver, mac80211, p54 wireless driver, the rest · Maintainers:
Jeff Johnson, Christian Lamparter, Johannes Berg, Linus Torvalds
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Use memset_after() so memset() doesn't get confused about writing beyond the destination member that is intended to be the starting point of zeroing through the end of the struct. Note that the common helper, ieee80211_tx_info_clear_status(), does NOT clear ack_signal, but the open-coded versions do. All three perform checks that the ack_signal position hasn't changed, though. Signed-off-by: Kees Cook <redacted> --- Should these each be clearing the same region? Because they're currently not. --- drivers/net/wireless/ath/carl9170/tx.c | 4 +--- drivers/net/wireless/intersil/p54/txrx.c | 4 +--- include/net/mac80211.h | 4 +--- 3 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
index 88444fe6d1c6..6d2115639434 100644
--- a/drivers/net/wireless/ath/carl9170/tx.c
+++ b/drivers/net/wireless/ath/carl9170/tx.c@@ -278,9 +278,7 @@ static void carl9170_tx_release(struct kref *ref) BUILD_BUG_ON( offsetof(struct ieee80211_tx_info, status.ack_signal) != 20); - memset(&txinfo->status.ack_signal, 0, - sizeof(struct ieee80211_tx_info) - - offsetof(struct ieee80211_tx_info, status.ack_signal)); + memset_after(&txinfo->status, 0, rates); if (atomic_read(&ar->tx_total_queued)) ar->tx_schedule = true;
diff --git a/drivers/net/wireless/intersil/p54/txrx.c b/drivers/net/wireless/intersil/p54/txrx.c
index 873fea59894f..f71b355f8583 100644
--- a/drivers/net/wireless/intersil/p54/txrx.c
+++ b/drivers/net/wireless/intersil/p54/txrx.c@@ -431,9 +431,7 @@ static void p54_rx_frame_sent(struct p54_common *priv, struct sk_buff *skb) * Clear manually, ieee80211_tx_info_clear_status would * clear the counts too and we need them. */ - memset(&info->status.ack_signal, 0, - sizeof(struct ieee80211_tx_info) - - offsetof(struct ieee80211_tx_info, status.ack_signal)); + memset_after(&info->status, 0, rates); BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, status.ack_signal) != 20);
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d8a1d09a2141..7abc1427aa8c 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h@@ -1200,9 +1200,7 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info) BUILD_BUG_ON( offsetof(struct ieee80211_tx_info, status.ack_signal) != 20); - memset(&info->status.ampdu_ack_len, 0, - sizeof(struct ieee80211_tx_info) - - offsetof(struct ieee80211_tx_info, status.ampdu_ack_len)); + memset_after(&info->status, 0, ack_signal); }
--
2.30.2