From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
syzbot <syzkaller@googlegroups.com>,
Neal Cardwell <ncardwell@google.com>,
Soheil Hassas Yeganeh <soheil@google.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.3 11/25] tcp: md5: fix potential overestimation of TCP option space
Date: Tue, 17 Dec 2019 21:16:10 +0100 [thread overview]
Message-ID: <20191217200908.055769377@linuxfoundation.org> (raw)
In-Reply-To: <20191217200903.179327435@linuxfoundation.org>
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 9424e2e7ad93ffffa88f882c9bc5023570904b55 ]
Back in 2008, Adam Langley fixed the corner case of packets for flows
having all of the following options : MD5 TS SACK
Since MD5 needs 20 bytes, and TS needs 12 bytes, no sack block
can be cooked from the remaining 8 bytes.
tcp_established_options() correctly sets opts->num_sack_blocks
to zero, but returns 36 instead of 32.
This means TCP cooks packets with 4 extra bytes at the end
of options, containing unitialized bytes.
Fixes: 33ad798c924b ("tcp: options clean up")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/tcp_output.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -755,8 +755,9 @@ static unsigned int tcp_established_opti
min_t(unsigned int, eff_sacks,
(remaining - TCPOLEN_SACK_BASE_ALIGNED) /
TCPOLEN_SACK_PERBLOCK);
- size += TCPOLEN_SACK_BASE_ALIGNED +
- opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
+ if (likely(opts->num_sack_blocks))
+ size += TCPOLEN_SACK_BASE_ALIGNED +
+ opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
}
return size;
next prev parent reply other threads:[~2019-12-17 20:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 20:15 [PATCH 5.3 00/25] 5.3.18-stable review Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 01/25] inet: protect against too small mtu values Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 02/25] mqprio: Fix out-of-bounds access in mqprio_dump Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 03/25] net: bridge: deny dev_set_mac_address() when unregistering Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 04/25] net: dsa: fix flow dissection on Tx path Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 05/25] net: ethernet: ti: cpsw: fix extra rx interrupt Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 06/25] net: sched: fix dump qlen for sch_mq/sch_mqprio with NOLOCK subqueues Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 07/25] net-sysfs: Call dev_hold always in netdev_queue_add_kobject Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 08/25] net: thunderx: start phy before starting autonegotiation Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 09/25] net/tls: Fix return values to avoid ENOTSUPP Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 10/25] openvswitch: support asymmetric conntrack Greg Kroah-Hartman
2019-12-17 20:16 ` Greg Kroah-Hartman [this message]
2019-12-17 20:16 ` [PATCH 5.3 12/25] tipc: fix ordering of tipc module init and exit routine Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 13/25] net/mlx5e: Query global pause state before setting prio2buffer Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 14/25] net: ipv6: add net argument to ip6_dst_lookup_flow Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 15/25] net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 16/25] tcp: fix rejected syncookies due to stale timestamps Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 17/25] tcp: tighten acceptance of ACKs not matching a child socket Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 18/25] tcp: Protect accesses to .ts_recent_stamp with {READ,WRITE}_ONCE() Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 19/25] gre: refetch erspan header from skb->data after pskb_may_pull() Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 20/25] Fixed updating of ethertype in function skb_mpls_pop Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 21/25] hsr: fix a NULL pointer dereference in hsr_dev_xmit() Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 22/25] net: Fixed updating of ethertype in skb_mpls_push() Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 23/25] net/mlx5e: Fix TXQ indices to be sequential Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 24/25] page_pool: do not release pool until inflight == 0 Greg Kroah-Hartman
2019-12-17 20:16 ` [PATCH 5.3 25/25] xdp: obtain the mem_id mutex before trying to remove an entry Greg Kroah-Hartman
2019-12-18 8:01 ` [PATCH 5.3 00/25] 5.3.18-stable review Naresh Kamboju
2019-12-18 10:23 ` Jon Hunter
2019-12-18 14:47 ` Guenter Roeck
2019-12-18 21:00 ` shuah
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