[PATCH] mac80211_hwsim: correctly handle zero length frames

From
Anirudh Rayabharam <hidden>
Date
2021-06-10 16:19:48
Also in
linux-kernel-mentees, linux-wireless, lkml
syzbot, using KMSAN, has reported an uninit-value access in
hwsim_cloned_frame_received_nl(). This is happening because frame_data_len
is 0. The code doesn't detect this case and blindly tries to read the
frame's header.

Fix this by bailing out in case frame_data_len is 0.

Reported-by: <redacted>
Tested-by: <redacted>
Signed-off-by: Anirudh Rayabharam <redacted>
---
 drivers/net/wireless/mac80211_hwsim.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 51ce767eaf88..ccfe40313109 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3649,7 +3649,7 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 	if (skb == NULL)
 		goto err;
 
-	if (frame_data_len > IEEE80211_MAX_DATA_LEN)
+	if (frame_data_len == 0 || frame_data_len > IEEE80211_MAX_DATA_LEN)
 		goto err;
 
 	/* Copy the data */
-- 
2.26.2
Thread (3 messages) 3 messages, 2 authors, last reply 2021-06-23
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