From e14bf37bb2b3853012ff160131d1c6233f7a9cc9 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 8 Sep 2026 14:28:12 +0200 Subject: [PATCH] wifi: mac80211: don't allow injecting frames wider than the chanctx Frames injected on a monitor interface can carry a radiotap field requesting a bandwidth, which mac80211 passes down to the driver regardless of the the actual operational bandwidth. If the bandwidth requested is too wide, that triggers a warning in hwsim: WARN_ON(hwsim_get_chanwidth(bw) > hwsim_get_chanwidth(confbw)) Drop such frames entirely instead since they cannot be sent. Assisted-by: LLM Fixes: 646e76bb5daf ("mac80211: parse VHT info in injected frames") Reported-by: syzbot+435fdb053cf98bfa5778@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=435fdb053cf98bfa5778 Link: https://patch.msgid.link/20260908122838.201719-13-johannes@sipsolutions.net Signed-off-by: Johannes Berg --- include/net/mac80211.h | 5 ++++- net/mac80211/iface.c | 2 +- net/mac80211/tx.c | 28 ++++++++++++++++++++++++++-- 3 files changed, 31 insertions(+), 4 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 9d1fac6e8082..ed6a5874ff96 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -7638,11 +7638,14 @@ bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw, * * @skb: packet injected by userspace * @dev: the &struct device of this 802.11 device + * @chandef: the channel definition the frame will be transmitted on, or + * %NULL to skip the bandwidth checks * * Return: %true if the radiotap header was parsed, %false otherwise */ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb, - struct net_device *dev); + struct net_device *dev, + const struct cfg80211_chan_def *chandef); /** * struct ieee80211_noa_data - holds temporary data for tracking P2P NoA state diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 842bfb4a7cb6..ca66eb493ac7 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -991,7 +991,7 @@ static u16 ieee80211_monitor_select_queue(struct net_device *dev, /* reset flags and info before parsing radiotap header */ memset(info, 0, sizeof(*info)); - if (!ieee80211_parse_tx_radiotap(skb, dev)) + if (!ieee80211_parse_tx_radiotap(skb, dev, NULL)) return 0; /* doesn't matter, frame will be dropped */ len_rthdr = ieee80211_get_radiotap_len(skb->data); diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index d155fb319a55..c343ed56506a 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2105,8 +2105,29 @@ static bool ieee80211_validate_radiotap_len(struct sk_buff *skb) return true; } +static bool ieee80211_rate_bw_usable(u16 rate_flags, + const struct cfg80211_chan_def *chandef) +{ + int width; + + if (!chandef) + return true; + + if (rate_flags & IEEE80211_TX_RC_160_MHZ_WIDTH) + width = 160; + else if (rate_flags & IEEE80211_TX_RC_80_MHZ_WIDTH) + width = 80; + else if (rate_flags & IEEE80211_TX_RC_40_MHZ_WIDTH) + width = 40; + else + return true; + + return width <= cfg80211_chandef_get_width(chandef); +} + bool ieee80211_parse_tx_radiotap(struct sk_buff *skb, - struct net_device *dev) + struct net_device *dev, + const struct cfg80211_chan_def *chandef) { struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr); struct ieee80211_radiotap_iterator iterator; @@ -2280,6 +2301,9 @@ bool ieee80211_parse_tx_radiotap(struct sk_buff *skb, struct ieee80211_supported_band *sband = local->hw.wiphy->bands[info->band]; + if (!ieee80211_rate_bw_usable(rate_flags, chandef)) + return false; + info->control.flags |= IEEE80211_TX_CTRL_RATE_INJECT; for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { @@ -2479,7 +2503,7 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb, * selected chandef above to accurately set injection rates and * retransmissions. */ - if (!ieee80211_parse_tx_radiotap(skb, dev)) + if (!ieee80211_parse_tx_radiotap(skb, dev, chandef)) goto fail_rcu; /* remove the injection radiotap header */