cfg80211: Check if PMKID attribute is of expected size

nla policy checks for only maximum length of the attribute data
when the attribute type is NLA_BINARY. If userspace sends less
data than specified, the wireless drivers may access illegal
memory. When type is NLA_UNSPEC, nla policy check ensures that
userspace sends minimum specified length number of bytes.

Remove type assignment to NLA_BINARY from nla_policy of
NL80211_ATTR_PMKID to make this NLA_UNSPEC and to make sure minimum
WLAN_PMKID_LEN bytes are received from userspace with
NL80211_ATTR_PMKID.

Fixes: 67fbb16be69d ("nl80211: PMKSA caching support")
Cc: stable@vger.kernel.org
Signed-off-by: Srinivas Dasari <dasaris@qti.qualcomm.com>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c3bc9da30cff..53ab5cae70c8 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -291,8 +291,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
         [NL80211_ATTR_WPA_VERSIONS] = { .type = NLA_U32 },
         [NL80211_ATTR_PID] = { .type = NLA_U32 },
         [NL80211_ATTR_4ADDR] = { .type = NLA_U8 },
-        [NL80211_ATTR_PMKID] = { .type = NLA_BINARY,
-                                 .len = WLAN_PMKID_LEN },
+        [NL80211_ATTR_PMKID] = { .len = WLAN_PMKID_LEN },
         [NL80211_ATTR_DURATION] = { .type = NLA_U32 },
         [NL80211_ATTR_COOKIE] = { .type = NLA_U64 },
         [NL80211_ATTR_TX_RATES] = { .type = NLA_NESTED },