mac80211: validate cipher scheme PN length better
Currently, a cipher scheme can advertise an arbitrarily long
sequence counter, but mac80211 only supports up to 16 bytes
and the initial value from userspace will be truncated.
Fix two things:
* don't allow the driver to register anything longer than
the 16 bytes that mac80211 reserves space for
* require userspace to specify a starting value with the
correct length (or none at all)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 0a5d5c5..2e67737 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -485,15 +485,17 @@
break;
default:
if (cs) {
- size_t len = (seq_len > IEEE80211_MAX_PN_LEN) ?
- IEEE80211_MAX_PN_LEN : seq_len;
+ if (seq_len && seq_len != cs->pn_len) {
+ kfree(key);
+ return ERR_PTR(-EINVAL);
+ }
key->conf.iv_len = cs->hdr_len;
key->conf.icv_len = cs->mic_len;
for (i = 0; i < IEEE80211_NUM_TIDS + 1; i++)
- for (j = 0; j < len; j++)
+ for (j = 0; j < seq_len; j++)
key->u.gen.rx_pn[i][j] =
- seq[len - j - 1];
+ seq[seq_len - j - 1];
key->flags |= KEY_FLAG_CIPHER_SCHEME;
}
}