From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25F432C98 for ; Fri, 22 Oct 2021 23:22:36 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10145"; a="292876385" X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="292876385" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 16:22:35 -0700 X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="495872237" Received: from gmonroy-mobl3.amr.corp.intel.com ([10.254.64.84]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 16:22:35 -0700 Date: Fri, 22 Oct 2021 16:22:35 -0700 (PDT) From: Mat Martineau To: Davide Caratti cc: Matthieu Baerts , Paolo Abeni , mptcp@lists.linux.dev, psonparo@redhat.com Subject: Re: [PATCH mptcp-net] mptcp: fix corrupt receiver key in MPC + data + checksum In-Reply-To: <1207c7d44dd4d1a630afc8b7018cf4185fe4a489.1634827708.git.dcaratti@redhat.com> Message-ID: References: <1207c7d44dd4d1a630afc8b7018cf4185fe4a489.1634827708.git.dcaratti@redhat.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="0-1867882193-1634944955=:37831" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-1867882193-1634944955=:37831 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8BIT On Thu, 21 Oct 2021, Davide Caratti wrote: > using packetdrill it's possible to observe that the receiver key contains > random values when clients transmit MP_CAPABLE with data and checksum (as > specified in RFC8684 ยง3.1). Fix the layout of mptcp_out_options, to avoid > using the skb extension copy when writing the MP_CAPABLE sub-option. > > Fixes: d7b269083786 ("mptcp: shrink mptcp_out_options struct") > Link: https://github.com/multipath-tcp/mptcp_net-next/issues/233 We generally use a "Closes:" tag for the github issues URL. > Reported-by: Poorva Sonparote > Signed-off-by: Davide Caratti > --- > include/net/mptcp.h | 4 ++++ > net/mptcp/options.c | 38 +++++++++++++++++++++++--------------- > 2 files changed, 27 insertions(+), 15 deletions(-) > > diff --git a/include/net/mptcp.h b/include/net/mptcp.h > index f83fa48408b3..a925349b4b89 100644 > --- a/include/net/mptcp.h > +++ b/include/net/mptcp.h > @@ -71,6 +71,10 @@ struct mptcp_out_options { > struct { > u64 sndr_key; > u64 rcvr_key; > + u64 data_seq; > + u32 subflow_seq; > + u16 data_len; > + __sum16 csum; > }; > struct { > struct mptcp_addr_info addr; > diff --git a/net/mptcp/options.c b/net/mptcp/options.c > index 422f4acfb3e6..ce27a4afc64a 100644 > --- a/net/mptcp/options.c > +++ b/net/mptcp/options.c > @@ -489,7 +489,7 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, > * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and > * TCPOLEN_MPTCP_MPC_ACK > */ There's an 'ext_copy' to edit out in the first line of this comment ^ (which is just before the above context lines) > - opts->ext_copy.data_len = data_len; > + opts->data_len = data_len; > opts->suboptions = OPTION_MPTCP_MPC_ACK; > opts->sndr_key = subflow->local_key; > opts->rcvr_key = subflow->remote_key; > @@ -505,9 +505,9 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, > len = TCPOLEN_MPTCP_MPC_ACK_DATA; > if (opts->csum_reqd) { > /* we need to propagate more info to csum the pseudo hdr */ > - opts->ext_copy.data_seq = mpext->data_seq; > - opts->ext_copy.subflow_seq = mpext->subflow_seq; > - opts->ext_copy.csum = mpext->csum; > + opts->data_seq = mpext->data_seq; > + opts->subflow_seq = mpext->subflow_seq; > + opts->csum = mpext->csum; > len += TCPOLEN_MPTCP_DSS_CHECKSUM; > } > *size = ALIGN(len, 4); > @@ -1223,25 +1223,30 @@ static void mptcp_set_rwin(const struct tcp_sock *tp) > WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); > } > > -static u16 mptcp_make_csum(const struct mptcp_ext *mpext) > +static u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __sum16 csum) > { > struct csum_pseudo_header header; > - __wsum csum; As the CI automation noticed, still need a __wsum to store the return value of csum_partial below. This is looking like the right way to go, with the noted few fixes. Thanks! > > /* cfr RFC 8684 3.3.1.: > * the data sequence number used in the pseudo-header is > * always the 64-bit value, irrespective of what length is used in the > * DSS option itself. > */ > - header.data_seq = cpu_to_be64(mpext->data_seq); > - header.subflow_seq = htonl(mpext->subflow_seq); > - header.data_len = htons(mpext->data_len); > + header.data_seq = cpu_to_be64(data_seq); > + header.subflow_seq = htonl(subflow_seq); > + header.data_len = htons(data_len); > header.csum = 0; > > - csum = csum_partial(&header, sizeof(header), ~csum_unfold(mpext->csum)); > + csum = csum_partial(&header, sizeof(header), ~csum_unfold(csum)); > return (__force u16)csum_fold(csum); > } > > +static u16 mptcp_make_csum(const struct mptcp_ext *mpext) > +{ > + return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len, > + mpext->csum); > +} > + > void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > struct mptcp_out_options *opts) > { > @@ -1332,7 +1337,7 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > len = TCPOLEN_MPTCP_MPC_SYN; > } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) { > len = TCPOLEN_MPTCP_MPC_SYNACK; > - } else if (opts->ext_copy.data_len) { > + } else if (opts->data_len) { > len = TCPOLEN_MPTCP_MPC_ACK_DATA; > if (opts->csum_reqd) > len += TCPOLEN_MPTCP_DSS_CHECKSUM; > @@ -1361,14 +1366,17 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, > > put_unaligned_be64(opts->rcvr_key, ptr); > ptr += 2; > - if (!opts->ext_copy.data_len) > + if (!opts->data_len) > goto mp_capable_done; > > if (opts->csum_reqd) { > - put_unaligned_be32(opts->ext_copy.data_len << 16 | > - mptcp_make_csum(&opts->ext_copy), ptr); > + put_unaligned_be32(opts->data_len << 16 | > + __mptcp_make_csum(opts->data_seq, > + opts->subflow_seq, > + opts->data_len, > + opts->csum), ptr); > } else { > - put_unaligned_be32(opts->ext_copy.data_len << 16 | > + put_unaligned_be32(opts->data_len << 16 | > TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); > } > ptr += 1; > -- > 2.31.1 > > -- Mat Martineau Intel --0-1867882193-1634944955=:37831--