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 <dan.carpenter@xxxxxxxxxx>
---
Use IEEE80211_MLD_MAX_NUM_LINKS as a limit instead of BITS_PER_LONG.
It's stricter and also more informative.
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 49447668cbf3..3604a8e15df0 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
