From: Yousef Alhouseen Date: Sun, 28 Jun 2026 00:25:37 +0000 (+0200) Subject: wifi: mac80211_hwsim: avoid treating MCS as legacy rate index X-Git-Tag: v7.2-rc4~17^2~16^2~33 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23b493d9dc5f00bba59347bd8ec7b044e26392a0;p=thirdparty%2Fkernel%2Flinux.git wifi: mac80211_hwsim: avoid treating MCS as legacy rate index Injected HT and VHT rates store an MCS value in rates[0].idx rather than an index into the legacy bitrate table. hwsim nevertheless passes these rates to ieee80211_get_tx_rate() while generating monitor frames and timestamps. A crafted injected frame can therefore read beyond the bitrate table. If the resulting bitrate is zero, mac80211_hwsim_write_tsf() also divides by zero, as observed by syzbot. Use ieee80211_get_tx_rate() only for legacy rates. The existing fallback continues to supply a conservative bitrate where hwsim does not yet calculate MCS rates. Reported-by: syzbot+21629c14aa749636db9d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=21629c14aa749636db9d Signed-off-by: Yousef Alhouseen Link: https://patch.msgid.link/20260628002537.23550-1-alhouseenyousef@gmail.com [drop wrong Fixes tag] Signed-off-by: Johannes Berg --- diff --git a/drivers/net/wireless/virtual/mac80211_hwsim_main.c b/drivers/net/wireless/virtual/mac80211_hwsim_main.c index 5c1718277599..956ff9b94526 100644 --- a/drivers/net/wireless/virtual/mac80211_hwsim_main.c +++ b/drivers/net/wireless/virtual/mac80211_hwsim_main.c @@ -1324,6 +1324,17 @@ static void mac80211_hwsim_set_tsf(struct ieee80211_hw *hw, } } +static struct ieee80211_rate * +mac80211_hwsim_get_tx_rate(struct ieee80211_hw *hw, + struct ieee80211_tx_info *info) +{ + if (info->control.rates[0].flags & + (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS)) + return NULL; + + return ieee80211_get_tx_rate(hw, info); +} + static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw, struct sk_buff *tx_skb, struct ieee80211_channel *chan) @@ -1333,7 +1344,7 @@ static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw, struct hwsim_radiotap_hdr *hdr; u16 flags, bitrate; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx_skb); - struct ieee80211_rate *txrate = ieee80211_get_tx_rate(hw, info); + struct ieee80211_rate *txrate = mac80211_hwsim_get_tx_rate(hw, info); if (!txrate) bitrate = 0; @@ -1603,7 +1614,7 @@ static void mac80211_hwsim_write_tsf(struct mac80211_hwsim_data *data, spin_lock_bh(&data->tsf_offset_lock); - txrate = ieee80211_get_tx_rate(data->hw, info); + txrate = mac80211_hwsim_get_tx_rate(data->hw, info); if (txrate) bitrate = txrate->bitrate;