From: Alexey Kuznetsov Date: Wed, 25 Apr 2007 20:59:03 +0000 (+0000) Subject: [PATCH] NETLINK: Infinite recursion in netlink. X-Git-Tag: v2.6.20.8~1 X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fstable%2Flinux-2.6.20.y.git;a=commitdiff_plain;h=9bc1779885f4ce1a4257c5640c70b75d2ae124ad [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 --- diff -urN linux-source-2.6.18.orig/net/ipv4/fib_frontend.c linux-source-2.6.18/net/ipv4/fib_frontend.c --- linux-source-2.6.18.orig/net/ipv4/fib_frontend.c 2006-09-19 21:42:06.000000000 -0600 +++ linux-source-2.6.18/net/ipv4/fib_frontend.c 2007-05-01 15:21:37.000000000 -0600 @@ -524,6 +524,8 @@ .fwmark = frn->fl_fwmark, .tos = frn->fl_tos, .scope = frn->fl_scope } } }; + + frn->err = -ENOENT; if (tb) { local_bh_disable(); @@ -535,6 +537,7 @@ frn->nh_sel = res.nh_sel; frn->type = res.type; frn->scope = res.scope; + fib_res_put(&res); } local_bh_enable(); } @@ -549,6 +552,9 @@ 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))) { @@ -561,7 +567,7 @@ 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_pid = pid; NETLINK_CB(skb).dst_group = 0; /* unicast */