We need this to be at least two bytes, so we can access alpha2[0] and alpha2[1]. It may be three in case some userspace used NUL-termination since it was NLA_STRING (and we also push it out with NUL-termination). Cc: stable@xxxxxxxxxxxxxxx Reported-by: Lee Jones <lee.jones@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220411114201.fd4a31f06541.Ie7ff4be2cf348d8cc28ed0d626fc54becf7ea799@changeid Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index ee1c2b6b6971..21e808fcb676 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -528,7 +528,8 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { .len = IEEE80211_MAX_MESH_ID_LEN }, [NL80211_ATTR_MPATH_NEXT_HOP] = NLA_POLICY_ETH_ADDR_COMPAT, - [NL80211_ATTR_REG_ALPHA2] = { .type = NLA_STRING, .len = 2 }, + /* allow 3 for NUL-termination, we used to declare this NLA_STRING */ + [NL80211_ATTR_REG_ALPHA2] = NLA_POLICY_RANGE(NLA_BINARY, 2, 3), [NL80211_ATTR_REG_RULES] = { .type = NLA_NESTED }, [NL80211_ATTR_BSS_CTS_PROT] = { .type = NLA_U8 },
