nl80211: fix NLA_POLICY_NESTED() arguments

syzbot reported an out-of-bounds read when passing certain
malformed messages into nl80211. The specific place where
this happened isn't interesting, the problem is that nested
policy parsing was referring to the wrong maximum attribute
and thus the policy wasn't long enough.

Fix this by referring to the correct attribute. Since this
is really not necessary, I'll come up with a separate patch
to just pass the policy instead of both, in the common case
we can infer the maxattr from the size of the policy array.

Reported-by: syzbot+4157b036c5f4713b1f2f@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Fixes: 419b7f3cbea3 ("cfg80211: add peer measurement with FTM initiator API")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 5e49492d5911d816c85bdec83af843e0a5235c1c..74150ad958239f631e34662fd1995eba148013ce 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -555,7 +555,7 @@ const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
        },
        [NL80211_ATTR_TIMEOUT] = NLA_POLICY_MIN(NLA_U32, 1),
        [NL80211_ATTR_PEER_MEASUREMENTS] =
-               NLA_POLICY_NESTED(NL80211_PMSR_FTM_REQ_ATTR_MAX,
+               NLA_POLICY_NESTED(NL80211_PMSR_ATTR_MAX,
                                  nl80211_pmsr_attr_policy),
 };