From: Du Cheng ducheng2@gmail.com
[ Upstream commit e298aa358f0ca658406d524b6639fe389cb6e11e ]
Replace hard-coded compile-time constants for header length check with dynamic determination based on the frame type. Otherwise, we hit a validation WARN_ON in cfg80211 later.
Fixes: cd418ba63f0c ("mac80211: convert S1G beacon to scan results") Reported-by: syzbot+405843667e93b9790fc1@syzkaller.appspotmail.com Signed-off-by: Du Cheng ducheng2@gmail.com Link: https://lore.kernel.org/r/20210510041649.589754-1-ducheng2@gmail.com [style fixes, reword commit message] Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/mac80211/scan.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index d4cc9ac2d703..6b50cb5e0e3c 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -251,13 +251,24 @@ void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) struct ieee80211_mgmt *mgmt = (void *)skb->data; struct ieee80211_bss *bss; struct ieee80211_channel *channel; + size_t min_hdr_len = offsetof(struct ieee80211_mgmt, + u.probe_resp.variable); + + if (!ieee80211_is_probe_resp(mgmt->frame_control) && + !ieee80211_is_beacon(mgmt->frame_control) && + !ieee80211_is_s1g_beacon(mgmt->frame_control)) + return;
if (ieee80211_is_s1g_beacon(mgmt->frame_control)) { - if (skb->len < 15) - return; - } else if (skb->len < 24 || - (!ieee80211_is_probe_resp(mgmt->frame_control) && - !ieee80211_is_beacon(mgmt->frame_control))) + if (ieee80211_is_s1g_short_beacon(mgmt->frame_control)) + min_hdr_len = offsetof(struct ieee80211_ext, + u.s1g_short_beacon.variable); + else + min_hdr_len = offsetof(struct ieee80211_ext, + u.s1g_beacon); + } + + if (skb->len < min_hdr_len) return;
sdata1 = rcu_dereference(local->scan_sdata);