netlink: reset extack earlier in netlink_rcv_skb

Move up the extack reset/initialization in netlink_rcv_skb, so that those 'goto ack' will not skip it. Otherwise, later on netlink_ack may use the uninitialized extack and cause kernel crash. Fixes: cbbdf84 ("netlink: extack needs to be reset each time through loop") Reported-by: [email protected] Signed-off-by: Xin Long <[email protected]> Acked-by: David Ahern <[email protected]> Signed-off-by: David S. Miller <[email protected]>
siemens · Jan 18, 2018 · cd443f1 · cd443f1
1 parent 7155f8f
commit cd443f1
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
@@ -2391,6 +2391,7 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 	while (skb->len >= nlmsg_total_size(0)) {
 		int msglen;
 
+		memset(&extack, 0, sizeof(extack));
 		nlh = nlmsg_hdr(skb);
 		err = 0;
 
@@ -2405,7 +2406,6 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
 			goto ack;
 
-		memset(&extack, 0, sizeof(extack));
 		err = cb(skb, nlh, &extack);
 		if (err == -EINTR)
 			goto skip;