From 74fbc288d30a6da65187bded5834f36097fd738e Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Thu, 1 Aug 2013 14:26:10 +0100 Subject: ipv6: call udp_push_pending_frames when uncorking a socket with AF_INET pending data CVE-2013-4162 BugLink: http://bugs.launchpad.net/bugs/1205070 We accidentally call down to ip6_push_pending_frames when uncorking pending AF_INET data on a ipv6 socket. This results in the following splat (from Dave Jones): skbuff: skb_under_panic: text:ffffffff816765f6 len:48 put:40 head:ffff88013deb6df0 data:ffff88013deb6dec tail:0x2c end:0xc0 dev: ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:126! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: dccp_ipv4 dccp 8021q garp bridge stp dlci mpoa snd_seq_dummy sctp fuse hidp tun bnep nfnetlink scsi_transport_iscsi rfcomm can_raw can_bcm af_802154 appletalk caif_socket can caif ipt_ULOG x25 rose af_key pppoe pppox ipx phonet irda llc2 ppp_generic slhc p8023 psnap p8022 llc crc_ccitt atm bluetooth +netrom ax25 nfc rfkill rds af_rxrpc coretemp hwmon kvm_intel kvm crc32c_intel snd_hda_codec_realtek ghash_clmulni_intel microcode pcspkr snd_hda_codec_hdmi snd_hda_intel snd_hda_codec snd_hwdep usb_debug snd_seq snd_seq_device snd_pcm e1000e snd_page_alloc snd_timer ptp snd pps_core soundcore xfs libcrc32c CPU: 2 PID: 8095 Comm: trinity-child2 Not tainted 3.10.0-rc7+ #37 task: ffff8801f52c2520 ti: ffff8801e6430000 task.ti: ffff8801e6430000 RIP: 0010:[] [] skb_panic+0x63/0x65 RSP: 0018:ffff8801e6431de8 EFLAGS: 00010282 RAX: 0000000000000086 RBX: ffff8802353d3cc0 RCX: 0000000000000006 RDX: 0000000000003b90 RSI: ffff8801f52c2ca0 RDI: ffff8801f52c2520 RBP: ffff8801e6431e08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff88022ea0c800 R13: ffff88022ea0cdf8 R14: ffff8802353ecb40 R15: ffffffff81cc7800 FS: 00007f5720a10740(0000) GS:ffff880244c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000005862000 CR3: 000000022843c000 CR4: 00000000001407e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Stack: ffff88013deb6dec 000000000000002c 00000000000000c0 ffffffff81a3f6e4 ffff8801e6431e18 ffffffff8159a9aa ffff8801e6431e90 ffffffff816765f6 ffffffff810b756b 0000000700000002 ffff8801e6431e40 0000fea9292aa8c0 Call Trace: [] skb_push+0x3a/0x40 [] ip6_push_pending_frames+0x1f6/0x4d0 [] ? mark_held_locks+0xbb/0x140 [] udp_v6_push_pending_frames+0x2b9/0x3d0 [] ? udplite_getfrag+0x20/0x20 [] udp_lib_setsockopt+0x1aa/0x1f0 [] ? fget_light+0x387/0x4f0 [] udpv6_setsockopt+0x34/0x40 [] sock_common_setsockopt+0x14/0x20 [] SyS_setsockopt+0x71/0xd0 [] tracesys+0xdd/0xe2 Code: 00 00 48 89 44 24 10 8b 87 d8 00 00 00 48 89 44 24 08 48 8b 87 e8 00 00 00 48 c7 c7 c0 04 aa 81 48 89 04 24 31 c0 e8 e1 7e ff ff <0f> 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 RIP [] skb_panic+0x63/0x65 RSP This patch adds a check if the pending data is of address family AF_INET and directly calls udp_push_ending_frames from udp_v6_push_pending_frames if that is the case. This bug was found by Dave Jones with trinity. (Also move the initialization of fl6 below the AF_INET check, even if not strictly necessary.) Cc: Dave Jones Cc: YOSHIFUJI Hideaki Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller (back ported from commit 8822b64a0fa64a5dd1dfcf837c5b0be83f8c05d1) Signed-off-by: Luis Henriques Acked-by: Brad Figg Signed-off-by: Tim Gardner Signed-off-by: Willy Tarreau --- net/ipv6/udp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'net/ipv6') diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3a9185909a46..d0367eb45ae3 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -687,11 +687,16 @@ static int udp_v6_push_pending_frames(struct sock *sk) struct udphdr *uh; struct udp_sock *up = udp_sk(sk); struct inet_sock *inet = inet_sk(sk); - struct flowi *fl = &inet->cork.fl; + struct flowi *fl; int err = 0; int is_udplite = IS_UDPLITE(sk); __wsum csum = 0; + if (up->pending == AF_INET) + return udp_push_pending_frames(sk); + + fl = &inet->cork.fl; + /* Grab the skbuff where UDP header space exists. */ if ((skb = skb_peek(&sk->sk_write_queue)) == NULL) goto out; -- cgit v1.2.3