--- /dev/null
+From git-commits-head-owner@vger.kernel.org Wed Apr 25 14:00:42 2007
+From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+Date: Wed, 25 Apr 2007 20:59:03 GMT
+Subject: NETLINK: Infinite recursion in netlink.
+To: git-commits-head@vger.kernel.org
+Message-ID: <200704252059.l3PKx3h7031374@hera.kernel.org>
+
+From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+
+[NETLINK]: Infinite recursion in netlink.
+
+Reply to NETLINK_FIB_LOOKUP messages were misrouted back to kernel,
+which resulted in infinite recursion and stack overflow.
+
+The bug is present in all kernel versions since the feature appeared.
+
+The patch also makes some minimal cleanup:
+
+1. Return something consistent (-ENOENT) when fib table is missing
+2. Do not crash when queue is empty (does not happen, but yet)
+3. Put result of lookup
+
+Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ net/ipv4/fib_frontend.c | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+--- a/net/ipv4/fib_frontend.c
++++ b/net/ipv4/fib_frontend.c
+@@ -772,6 +772,8 @@ static void nl_fib_lookup(struct fib_res
+ .nl_u = { .ip4_u = { .daddr = frn->fl_addr,
+ .tos = frn->fl_tos,
+ .scope = frn->fl_scope } } };
++
++ frn->err = -ENOENT;
+ if (tb) {
+ local_bh_disable();
+
+@@ -783,6 +785,7 @@ static void nl_fib_lookup(struct fib_res
+ frn->nh_sel = res.nh_sel;
+ frn->type = res.type;
+ frn->scope = res.scope;
++ fib_res_put(&res);
+ }
+ local_bh_enable();
+ }
+@@ -797,6 +800,9 @@ static void nl_fib_input(struct sock *sk
+ struct fib_table *tb;
+
+ skb = skb_dequeue(&sk->sk_receive_queue);
++ if (skb == NULL)
++ return;
++
+ nlh = (struct nlmsghdr *)skb->data;
+ if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
+ nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
+@@ -809,7 +815,7 @@ static void nl_fib_input(struct sock *sk
+
+ nl_fib_lookup(frn, tb);
+
+- pid = nlh->nlmsg_pid; /*pid of sending process */
++ pid = NETLINK_CB(skb).pid; /* pid of sending process */
+ NETLINK_CB(skb).pid = 0; /* from kernel */
+ NETLINK_CB(skb).dst_group = 0; /* unicast */
+ netlink_unicast(sk, skb, pid, MSG_DONTWAIT);