[NETLINK]: Fix processing of fib_lookup netlink messages
The receive path for fib_lookup netlink messages is lacking sanity
checks for header and payload and is thus vulnerable to malformed
netlink messages causing illegal memory references.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 882f88f..19b1b98 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -544,12 +544,16 @@
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh = NULL;
struct fib_result_nl *frn;
- int err;
u32 pid;
struct fib_table *tb;
- skb = skb_recv_datagram(sk, 0, 0, &err);
+ skb = skb_dequeue(&sk->sk_receive_queue);
nlh = (struct nlmsghdr *)skb->data;
+ if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
+ nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
+ kfree_skb(skb);
+ return;
+ }
frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
tb = fib_get_table(frn->tb_id_in);