[PATCH v3] wifi: mac80211: check basic rates validity in sta_link_apply_parameters

[Mikhail Lobanov]

When userspace sets supported rates for a new station via
NL80211_CMD_NEW_STATION, it might send a list that's empty
or contains only invalid values. Currently, we process these
values in sta_link_apply_parameters() without checking the result of
ieee80211_parse_bitrates(), which can lead to an empty rates bitmap.

A similar issue was addressed for NL80211_CMD_SET_BSS in commit
ce04abc3fcc6 ("wifi: mac80211: check basic rates validity").
This patch applies the same approach in sta_link_apply_parameters()
for NL80211_CMD_NEW_STATION, ensuring there is at least one valid
rate by inspecting the result of ieee80211_parse_bitrates().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: b95eb7f0eee4 ("wifi: cfg80211/mac80211: separate link params from station params")
Signed-off-by: Mikhail Lobanov <m.lobanov@xxxxxxx>
---
v2: Fixed the patch subject to provide a complete description.
v3: added the missing if as Christophe Jaillet (christophe.jaillet@xxxxxxxxxx) noticed.

 net/mac80211/cfg.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 9351c64608a9..b4d18172da16 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1909,10 +1909,11 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
 
 	if (params->supported_rates &&
 	    params->supported_rates_len) {
-		ieee80211_parse_bitrates(link->conf->chanreq.oper.width,
-					 sband, params->supported_rates,
-					 params->supported_rates_len,
-					 &link_sta->pub->supp_rates[sband->band]);
+		if (!ieee80211_parse_bitrates(link->conf->chanreq.oper.width,
+					      sband, params->supported_rates,
+					      params->supported_rates_len,
+					      &link_sta->pub->supp_rates[sband->band]))
+			return -EINVAL;
 	}
 
 	if (params->ht_capa)
-- 
2.47.2