| Message ID | 1486501187-12869-1-git-send-email-xiyou.wangcong@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Cong Wang <xiyou.wangcong@gmail.com> Date: Tue, 7 Feb 2017 12:59:46 -0800 > Andrey reported a kernel crash: ... > This is because we miss a check for NULL pointer for skb_peek() when > the queue is empty. Other places already have the same check. > > Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind") > Reported-by: Andrey Konovalov <andreyknvl@google.com> > Tested-by: Andrey Konovalov <andreyknvl@google.com> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Applied and queued up for -stable, thanks Cong.
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 86cca61..68d77b1 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -642,6 +642,8 @@ static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh, { struct sk_buff *skb = skb_peek(&sk->sk_write_queue); + if (!skb) + return 0; pfh->wcheck = csum_partial((char *)&pfh->icmph, sizeof(struct icmphdr), pfh->wcheck); pfh->icmph.checksum = csum_fold(pfh->wcheck);
Andrey reported a kernel crash: general protection fault: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 2 PID: 3880 Comm: syz-executor1 Not tainted 4.10.0-rc6+ #124 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff880060048040 task.stack: ffff880069be8000 RIP: 0010:ping_v4_push_pending_frames net/ipv4/ping.c:647 [inline] RIP: 0010:ping_v4_sendmsg+0x1acd/0x23f0 net/ipv4/ping.c:837 RSP: 0018:ffff880069bef8b8 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff880069befb90 RCX: 0000000000000000 RDX: 0000000000000018 RSI: ffff880069befa30 RDI: 00000000000000c2 RBP: ffff880069befbb8 R08: 0000000000000008 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: ffff880069befab0 R13: ffff88006c624a80 R14: ffff880069befa70 R15: 0000000000000000 FS: 00007f6f7c716700(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004a6f28 CR3: 000000003a134000 CR4: 00000000000006e0 Call Trace: inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xca/0x110 net/socket.c:645 SYSC_sendto+0x660/0x810 net/socket.c:1687 SyS_sendto+0x40/0x50 net/socket.c:1655 entry_SYSCALL_64_fastpath+0x1f/0xc2 This is because we miss a check for NULL pointer for skb_peek() when the queue is empty. Other places already have the same check. Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind") Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- net/ipv4/ping.c | 2 ++ 1 file changed, 2 insertions(+)