Ack: [Lucid][CVE-2013-4162] ipv6: call udp_push_pending_frames when uncorking a socket with AF_INET pending data
Brad Figg
brad.figg at canonical.com
Thu Aug 1 15:57:54 UTC 2013
On 08/01/2013 02:26 PM, Luis Henriques wrote:
> From: Hannes Frederic Sowa <hannes at stressinduktion.org>
>
> 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:<NULL>
> ------------[ 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:[<ffffffff816e759c>] [<ffffffff816e759c>] 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:
> [<ffffffff8159a9aa>] skb_push+0x3a/0x40
> [<ffffffff816765f6>] ip6_push_pending_frames+0x1f6/0x4d0
> [<ffffffff810b756b>] ? mark_held_locks+0xbb/0x140
> [<ffffffff81694919>] udp_v6_push_pending_frames+0x2b9/0x3d0
> [<ffffffff81694660>] ? udplite_getfrag+0x20/0x20
> [<ffffffff8162092a>] udp_lib_setsockopt+0x1aa/0x1f0
> [<ffffffff811cc5e7>] ? fget_light+0x387/0x4f0
> [<ffffffff816958a4>] udpv6_setsockopt+0x34/0x40
> [<ffffffff815949f4>] sock_common_setsockopt+0x14/0x20
> [<ffffffff81593c31>] SyS_setsockopt+0x71/0xd0
> [<ffffffff816f5d54>] 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 [<ffffffff816e759c>] skb_panic+0x63/0x65
> RSP <ffff8801e6431de8>
>
> 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 <davej at redhat.com>
> Cc: YOSHIFUJI Hideaki <yoshfuji at linux-ipv6.org>
> Signed-off-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (back ported from commit 8822b64a0fa64a5dd1dfcf837c5b0be83f8c05d1)
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
> include/net/udp.h | 1 +
> net/ipv4/udp.c | 3 ++-
> net/ipv6/udp.c | 7 ++++++-
> 3 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/udp.h b/include/net/udp.h
> index f98abd2..702bea0 100644
> --- a/include/net/udp.h
> +++ b/include/net/udp.h
> @@ -134,6 +134,7 @@ extern void udp_err(struct sk_buff *, u32);
>
> extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
> struct msghdr *msg, size_t len);
> +extern int udp_push_pending_frames(struct sock *sk);
> extern void udp_flush_pending_frames(struct sock *sk);
>
> extern int udp_rcv(struct sk_buff *skb);
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 89e1f53..1357cee 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -513,7 +513,7 @@ static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
> /*
> * Push out all pending data as one UDP datagram. Socket is locked.
> */
> -static int udp_push_pending_frames(struct sock *sk)
> +int udp_push_pending_frames(struct sock *sk)
> {
> struct udp_sock *up = udp_sk(sk);
> struct inet_sock *inet = inet_sk(sk);
> @@ -575,6 +575,7 @@ out:
> up->pending = 0;
> return err;
> }
> +EXPORT_SYMBOL(udp_push_pending_frames);
>
> int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
> size_t len)
> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
> index 4467417..e0059e8 100644
> --- a/net/ipv6/udp.c
> +++ b/net/ipv6/udp.c
> @@ -735,11 +735,16 @@ 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;
>
--
Brad Figg brad.figg at canonical.com http://www.canonical.com
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