From f8a2fc809bfeb49130709b31a4d357a049f28547 Mon Sep 17 00:00:00 2001 From: Yi Cong Date: Fri, 6 Mar 2026 15:16:27 +0800 Subject: [PATCH] wifi: rtl8xxxu: fix potential use of uninitialized value The local variables 'mcs' and 'nss' in rtl8xxxu_update_ra_report() are passed to rtl8xxxu_desc_to_mcsrate() as output parameters. If the helper function encounters an unhandled rate index, it may return without setting these values, leading to the use of uninitialized stack data. Remove the helper rtl8xxxu_desc_to_mcsrate() and inline the logic into rtl8xxxu_update_ra_report(). This fixes the use of uninitialized 'mcs' and 'nss' variables for legacy rates. The new implementation explicitly handles: - Legacy rates: Set bitrate only. - HT rates (MCS0-15): Set MCS flags, index, and NSS (1 or 2) directly. - Invalid rates: Return early. Fixes: 7de16123d9e2 ("wifi: rtl8xxxu: Introduce rtl8xxxu_update_ra_report") Cc: stable@vger.kernel.org Suggested-by: Ping-Ke Shih Signed-off-by: Yi Cong Link: https://lore.kernel.org/all/96e31963da0c42dcb52ce44f818963d7@realtek.com/ Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/20260306071627.56501-1-cong.yi@linux.dev --- drivers/net/wireless/realtek/rtl8xxxu/core.c | 28 ++++++-------------- 1 file changed, 8 insertions(+), 20 deletions(-) diff --git a/drivers/net/wireless/realtek/rtl8xxxu/core.c b/drivers/net/wireless/realtek/rtl8xxxu/core.c index b4efc6f00a379..d1b1474cba677 100644 --- a/drivers/net/wireless/realtek/rtl8xxxu/core.c +++ b/drivers/net/wireless/realtek/rtl8xxxu/core.c @@ -4697,20 +4697,6 @@ static const struct ieee80211_rate rtl8xxxu_legacy_ratetable[] = { {.bitrate = 540, .hw_value = 0x0b,}, }; -static void rtl8xxxu_desc_to_mcsrate(u16 rate, u8 *mcs, u8 *nss) -{ - if (rate <= DESC_RATE_54M) - return; - - if (rate >= DESC_RATE_MCS0 && rate <= DESC_RATE_MCS15) { - if (rate < DESC_RATE_MCS8) - *nss = 1; - else - *nss = 2; - *mcs = rate - DESC_RATE_MCS0; - } -} - static void rtl8xxxu_set_basic_rates(struct rtl8xxxu_priv *priv, u32 rate_cfg) { struct ieee80211_hw *hw = priv->hw; @@ -4820,23 +4806,25 @@ static void rtl8xxxu_set_aifs(struct rtl8xxxu_priv *priv, u8 slot_time) void rtl8xxxu_update_ra_report(struct rtl8xxxu_ra_report *rarpt, u8 rate, u8 sgi, u8 bw) { - u8 mcs, nss; - rarpt->txrate.flags = 0; if (rate <= DESC_RATE_54M) { rarpt->txrate.legacy = rtl8xxxu_legacy_ratetable[rate].bitrate; - } else { - rtl8xxxu_desc_to_mcsrate(rate, &mcs, &nss); + } else if (rate >= DESC_RATE_MCS0 && rate <= DESC_RATE_MCS15) { rarpt->txrate.flags |= RATE_INFO_FLAGS_MCS; + if (rate < DESC_RATE_MCS8) + rarpt->txrate.nss = 1; + else + rarpt->txrate.nss = 2; - rarpt->txrate.mcs = mcs; - rarpt->txrate.nss = nss; + rarpt->txrate.mcs = rate - DESC_RATE_MCS0; if (sgi) rarpt->txrate.flags |= RATE_INFO_FLAGS_SHORT_GI; rarpt->txrate.bw = bw; + } else { + return; } rarpt->bit_rate = cfg80211_calculate_bitrate(&rarpt->txrate); -- 2.47.3