From 9bc1779885f4ce1a4257c5640c70b75d2ae124ad Mon Sep 17 00:00:00 2001 From: Alexey Kuznetsov Date: Wed, 25 Apr 2007 20:59:03 +0000 Subject: [PATCH] NETLINK: Infinite recursion in netlink. [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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/fib_frontend.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index d47b72af89ed..fa2cb8c29891 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -772,6 +772,8 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb ) .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_result_nl *frn, struct fib_table *tb ) 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, int len) 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, int len) 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); -- cgit v1.2.3