From: Mat Martineau <mathew.j.martineau@linux•intel.com>
To: Maxim Mikityanskiy <maximmi@nvidia•com>
Cc: "Matthieu Baerts" <matthieu.baerts@tessares•net>,
"Jakub Kicinski" <kuba@kernel•org>,
"David S. Miller" <davem@davemloft•net>,
"Pablo Neira Ayuso" <pablo@netfilter•org>,
"Jozsef Kadlecsik" <kadlec@netfilter•org>,
"Florian Westphal" <fw@strlen•de>,
"Toke Høiland-Jørgensen" <toke@toke•dk>,
"Jamal Hadi Salim" <jhs@mojatatu•com>,
"Cong Wang" <xiyou.wangcong@gmail•com>,
"Jiri Pirko" <jiri@resnulli•us>,
"Patrick McHardy" <kaber@trash•net>,
"Jesper Dangaard Brouer" <brouer@redhat•com>,
"Paolo Abeni" <pabeni@redhat•com>,
"Christoph Paasch" <cpaasch@apple•com>,
"Peter Krystad" <peter.krystad@linux•intel.com>,
"Young Xiao" <92siuyang@gmail•com>,
netdev@vger•kernel.org
Subject: Re: [PATCH net 2/3] mptcp: Fix out of bounds when parsing TCP options
Date: Wed, 9 Jun 2021 17:07:14 -0700 (PDT) [thread overview]
Message-ID: <c7caefb9-1aed-5bc9-b429-925412994249@linux.intel.com> (raw)
In-Reply-To: <20210609142212.3096691-3-maximmi@nvidia.com>
On Wed, 9 Jun 2021, Maxim Mikityanskiy wrote:
> The TCP option parser in mptcp (mptcp_get_options) could read one byte
> out of bounds. When the length is 1, the execution flow gets into the
> loop, reads one byte of the opcode, and if the opcode is neither
> TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the
> length of 1.
>
> This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack
> out of bounds when parsing TCP options.").
>
> Cc: Young Xiao <92siuyang@gmail•com>
> Fixes: cec37a6e41aa ("mptcp: Handle MP_CAPABLE options for outgoing connections")
> Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia•com>
> ---
> net/mptcp/options.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 6b825fb3fa83..9b263f27ce9b 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -356,6 +356,8 @@ void mptcp_get_options(const struct sk_buff *skb,
> length--;
> continue;
> default:
> + if (length < 2)
> + return;
> opsize = *ptr++;
> if (opsize < 2) /* "silly options" */
> return;
> --
> 2.25.1
Florian's comment on patch 1 prompted me to double-check th->doff
validation, and for MPTCP we're covered by the check in tcp_v4_rcv(). So
this patch looks good:
Reviewed-by: Mat Martineau <mathew.j.martineau@linux•intel.com>
If you send a v2 series, please also cc: mptcp@lists•linux.dev
Thanks!
--
Mat Martineau
Intel
next prev parent reply other threads:[~2021-06-10 0:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 14:22 [PATCH net 0/3] Fix out of bounds when parsing TCP options Maxim Mikityanskiy
2021-06-09 14:22 ` [PATCH net 1/3] netfilter: synproxy: " Maxim Mikityanskiy
2021-06-09 14:51 ` Florian Westphal
2021-06-10 7:05 ` Maxim Mikityanskiy
2021-06-10 8:56 ` Florian Westphal
2021-06-09 14:22 ` [PATCH net 2/3] mptcp: " Maxim Mikityanskiy
2021-06-10 0:07 ` Mat Martineau [this message]
2021-06-09 14:22 ` [PATCH net 3/3] sch_cake: " Maxim Mikityanskiy
2021-06-09 21:51 ` Toke Høiland-Jørgensen
2021-06-10 11:19 ` Maxim Mikityanskiy
2021-06-10 14:33 ` Toke Høiland-Jørgensen
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