From 1194ed0a3eb8076c8fbfe310f1ccbf229e8647de Mon Sep 17 00:00:00 2001 From: Alexey Kuznetsov Date: Wed, 25 Apr 2007 13:07:28 -0700 Subject: [PATCH] [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 --- 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 fc920f63452b..cac06c43f004 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -776,6 +776,8 @@ 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(); @@ -787,6 +789,7 @@ 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(); } @@ -801,6 +804,9 @@ 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))) { @@ -813,7 +819,7 @@ 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); -- 2.30.2