macsec: fix NULL deref in macsec_add_rxsa

Commit 48ef50f added a test on tb_sa[MACSEC_SA_ATTR_PN], but nothing guarantees that it's not NULL at this point. The same code was added to macsec_add_txsa, but there it's not a problem because validate_add_txsa checks that the MACSEC_SA_ATTR_PN attribute is present. Note: it's not possible to reproduce with iproute, because iproute doesn't allow creating an SA without specifying the PN. Fixes: 48ef50f ("macsec: Netlink support of XPN cipher suites (IEEE 802.1AEbw)") Link: https://bugzilla.kernel.org/show_bug.cgi?id=208315 Reported-by: Frantisek Sumsal <[email protected]> Signed-off-by: Sabrina Dubroca <[email protected]> Signed-off-by: David S. Miller <[email protected]>
majek · Jul 25, 2022 · f46040e · f46040e
1 parent 1aaa62c
commit f46040e
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
@@ -1753,7 +1753,8 @@ static int macsec_add_rxsa(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	pn_len = secy->xpn ? MACSEC_XPN_PN_LEN : MACSEC_DEFAULT_PN_LEN;
-	if (nla_len(tb_sa[MACSEC_SA_ATTR_PN]) != pn_len) {
+	if (tb_sa[MACSEC_SA_ATTR_PN] &&
+	    nla_len(tb_sa[MACSEC_SA_ATTR_PN]) != pn_len) {
 		pr_notice("macsec: nl: add_rxsa: bad pn length: %d != %d\n",
 			  nla_len(tb_sa[MACSEC_SA_ATTR_PN]), pn_len);
 		rtnl_unlock();