From 53cf488927a0f79968f9c03c4d1e00d2a79731c3 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 28 May 2025 11:11:02 +0300 Subject: [PATCH] wifi: rtw89: mcc: prevent shift wrapping in rtw89_core_mlsr_switch() The "link_id" value comes from the user via debugfs. If it's larger than BITS_PER_LONG then that would result in shift wrapping and potentially an out of bounds access later. In fact, we can limit it to IEEE80211_MLD_MAX_NUM_LINKS (15). Fortunately, only root can write to debugfs files so the security impact is minimal. Fixes: 9dd85e739ce0 ("wifi: rtw89: debug: add mlo_mode dbgfs") Signed-off-by: Dan Carpenter Reviewed-by: Zong-Zhe Yang Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/aDbFFkX09K7FrL9h@stanley.mountain --- drivers/net/wireless/realtek/rtw89/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/realtek/rtw89/core.c b/drivers/net/wireless/realtek/rtw89/core.c index 49447668cbf3d..3604a8e15df06 100644 --- a/drivers/net/wireless/realtek/rtw89/core.c +++ b/drivers/net/wireless/realtek/rtw89/core.c @@ -5239,7 +5239,8 @@ int rtw89_core_mlsr_switch(struct rtw89_dev *rtwdev, struct rtw89_vif *rtwvif, if (unlikely(!ieee80211_vif_is_mld(vif))) return -EOPNOTSUPP; - if (unlikely(!(usable_links & BIT(link_id)))) { + if (unlikely(link_id >= IEEE80211_MLD_MAX_NUM_LINKS || + !(usable_links & BIT(link_id)))) { rtw89_warn(rtwdev, "%s: link id %u is not usable\n", __func__, link_id); return -ENOLINK; -- 2.47.2