[PATCH wireless v2] wifi: mt76: mt76x02: validate TX-status rate index before mac80211 handoff
From: Mark Anthony Agarro <hidden>
Date: 2026-08-26 09:28:10
Also in:
linux-mediatek, stable
Subsystem:
mediatek mt76 wireless lan driver, the rest · Maintainers:
Felix Fietkau, Lorenzo Bianconi, Ryder Lee, Linus Torvalds
mt76x02_mac_process_tx_rate() extracts the rate index straight from
the hardware's raw TX-status word with no bounds check for the
HT/HT_GF/VHT cases, and mt76x02_mac_fill_tx_status() ignores its
return value. A stale or corrupt hardware index reaches mac80211's
minstrel_ht rate control, whose per-group rate array is a fixed 10
entries (MCS_GROUP_RATES), causing an out-of-bounds write.
Validate the index in mt76x02_mac_process_tx_rate() (HT: 0-31,
VHT: MCS nibble 0-9) and have mt76x02_mac_fill_tx_status() bail out
cleanly on failure instead of passing an invalid index through.
Fixes: 7c1f88812690 ("mt76: unify send_tx_status and related helpers")
Cc: stable@vger.kernel.org
Closes: https://github.com/morrownr/mt76/issues/88
Tested-by: Devin Wittmayer <redacted>
Signed-off-by: Mark Anthony Agarro <redacted>
---
v2: Drop the Reported-by tag. It named an invented
users.noreply.github.com address for the reporter that isn't a
real, deliverable mailbox (v1's Cc bounced with NXDOMAIN on that
domain). Closes: already credits and links the original report;
no functional change.
.../net/wireless/mediatek/mt76/mt76x02_mac.c | 27 ++++++++++++++-----
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
index 14ee5b3b9..d77356a2e 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c@@ -302,10 +302,22 @@ mt76x02_mac_process_tx_rate(struct ieee80211_tx_rate *txrate, u16 rate, txrate->flags |= IEEE80211_TX_RC_GREEN_FIELD; fallthrough; case MT_PHY_TYPE_HT: + /* Raw hardware TX-status index is unvalidated; a stale or + * corrupt value here overflows mac80211/minstrel_ht's + * per-group rate array (MCS_GROUP_RATES == 10) and crashes. + * Valid 802.11n MCS indices are 0-31 (four streams x 8). + */ + if (idx > 31) + return -EINVAL; txrate->flags |= IEEE80211_TX_RC_MCS; txrate->idx = idx; break; case MT_PHY_TYPE_VHT: + /* Same overflow risk for VHT: mac80211 expects the MCS + * nibble (bits 3:0) in range 0-9, nss packed above it. + */ + if ((idx & 0xf) > 9) + return -EINVAL; txrate->flags |= IEEE80211_TX_RC_VHT_MCS; txrate->idx = idx; break;
@@ -493,18 +505,21 @@ mt76x02_mac_fill_tx_status(struct mt76x02_dev *dev, struct mt76x02_sta *msta, first_rate = st->rate & ~MT_PKTID_RATE; first_rate |= st->pktid & MT_PKTID_RATE; - mt76x02_mac_process_tx_rate(&rate[0], first_rate, - dev->mphy.chandef.chan->band); + if (mt76x02_mac_process_tx_rate(&rate[0], first_rate, + dev->mphy.chandef.chan->band)) + return; } else if (rate[0].idx < 0) { if (!msta) return; - mt76x02_mac_process_tx_rate(&rate[0], msta->wcid.tx_info, - dev->mphy.chandef.chan->band); + if (mt76x02_mac_process_tx_rate(&rate[0], msta->wcid.tx_info, + dev->mphy.chandef.chan->band)) + return; } - mt76x02_mac_process_tx_rate(&last_rate, st->rate, - dev->mphy.chandef.chan->band); + if (mt76x02_mac_process_tx_rate(&last_rate, st->rate, + dev->mphy.chandef.chan->band)) + return; for (i = 0; i < ARRAY_SIZE(info->status.rates); i++) { retry--;
--
2.47.3