From 72fb96e7bdbbdd4421b0726992496531060f3636 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 9 Feb 2017 16:15:52 -0800 Subject: l2tp: do not use udp_ioctl() udp_ioctl(), as its name suggests, is used by UDP protocols, but is also used by L2TP :( L2TP should use its own handler, because it really does not look the same. SIOCINQ for instance should not assume UDP checksum or headers. Thanks to Andrey and syzkaller team for providing the report and a nice reproducer. While crashes only happen on recent kernels (after commit 7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue")), this probably needs to be backported to older kernels. Fixes: 7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue") Fixes: 85584672012e ("udp: Fix udp_poll() and ioctl()") Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Acked-by: Paolo Abeni Signed-off-by: David S. Miller --- net/l2tp/l2tp_ip.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'net/l2tp/l2tp_ip.c') diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 3d73278b86ca..28c21546d5b6 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -11,6 +11,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -553,6 +554,30 @@ out: return err ? err : copied; } +int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg) +{ + struct sk_buff *skb; + int amount; + + switch (cmd) { + case SIOCOUTQ: + amount = sk_wmem_alloc_get(sk); + break; + case SIOCINQ: + spin_lock_bh(&sk->sk_receive_queue.lock); + skb = skb_peek(&sk->sk_receive_queue); + amount = skb ? skb->len : 0; + spin_unlock_bh(&sk->sk_receive_queue.lock); + break; + + default: + return -ENOIOCTLCMD; + } + + return put_user(amount, (int __user *)arg); +} +EXPORT_SYMBOL(l2tp_ioctl); + static struct proto l2tp_ip_prot = { .name = "L2TP/IP", .owner = THIS_MODULE, @@ -561,7 +586,7 @@ static struct proto l2tp_ip_prot = { .bind = l2tp_ip_bind, .connect = l2tp_ip_connect, .disconnect = l2tp_ip_disconnect, - .ioctl = udp_ioctl, + .ioctl = l2tp_ioctl, .destroy = l2tp_ip_destroy_sock, .setsockopt = ip_setsockopt, .getsockopt = ip_getsockopt, -- cgit v1.2.3-70-g09d2