[IPV4]: OOPS with NETLINK_FIB_LOOKUP netlink socket
[ Regression added by changeset:
cd40b7d3983c708aabe3d3008ec64ffce56d33b0
[NET]: make netlink user -> kernel interface synchronious
-DaveM ]
nl_fib_input re-reuses incoming skb to send the reply. This means that this
packet will be freed twice, namely in:
- netlink_unicast_kernel
- on receive path
Use clone to send as a cure, the caller is responsible for kfree_skb on error.
Thanks to Alexey Dobryan, who originally found the problem.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 732d8f0..97abf93 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -804,10 +804,13 @@
nlh = nlmsg_hdr(skb);
if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
- nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
- kfree_skb(skb);
+ nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn)))
return;
- }
+
+ skb = skb_clone(skb, GFP_KERNEL);
+ if (skb == NULL)
+ return;
+ nlh = nlmsg_hdr(skb);
frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
tb = fib_get_table(frn->tb_id_in);