[PATCH AUTOSEL 6.4 34/41] wifi: mac80211_hwsim: drop short frames

Sasha Levin
2023-09-08T18:21:10Z

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit fba360a047d5eeeb9d4b7c3a9b1c8308980ce9a6 ]

While technically some control frames like ACK are shorter and
end after Address 1, such frames shouldn't be forwarded through
wmediumd or similar userspace, so require the full 3-address
header to avoid accessing invalid memory if shorter frames are
passed in.

Reported-by: syzbot+b2645b5bf1512b81fa22@syzkaller.appspotmail.com
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/virtual/mac80211_hwsim.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.c b/drivers/net/wireless/virtual/mac80211_hwsim.c
index ed5af63025979..6be374f4c9349 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim.c
@@ -5617,14 +5617,15 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
frame_data_len = nla_len(info->attrs[HWSIM_ATTR_FRAME]);
frame_data = (void *)nla_data(info->attrs[HWSIM_ATTR_FRAME]);

+ if (frame_data_len < sizeof(struct ieee80211_hdr_3addr) ||
+ frame_data_len > IEEE80211_MAX_DATA_LEN)
+ goto err;
+
/* Allocate new skb here */
skb = alloc_skb(frame_data_len, GFP_KERNEL);
if (skb == NULL)
goto err;

- if (frame_data_len > IEEE80211_MAX_DATA_LEN)
- goto err;
-
/* Copy the data */
skb_put_data(skb, frame_data, frame_data_len);

--
2.40.1