The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x e32d262c89e2b22cb0640223f953b548617ed8a6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024101414-scouting-grower-43fe@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

e32d262c89e2 ("mptcp: handle consistently DSS corruption") 104125b82e5c ("mptcp: add mib for infinite map sending") 1e39e5a32ad7 ("mptcp: infinite mapping sending") 0eb4e7ee1655 ("mptcp: add tracepoint in mptcp_sendmsg_frag") f284c0c77321 ("mptcp: implement fastclose xmit path") f70cad1085d1 ("mptcp: stop relying on tcp_tx_skb_cache") efe686ffce01 ("mptcp: ensure tx skbs always have the MPTCP ext") 1094c6fe7280 ("mptcp: fix possible divide by zero") 5580d41b758a ("mptcp: MP_FAIL suboption receiving") c25aeb4e0953 ("mptcp: MP_FAIL suboption sending") d7b269083786 ("mptcp: shrink mptcp_out_options struct") 1bff1e43a30e ("mptcp: optimize out option generation") 1f5e9e2f5fd5 ("mptcp: move drop_other_suboptions check under pm lock") df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") bab6b88e0560 ("mptcp: add allow_join_id0 in mptcp_out_options") 8ce568ed06ce ("mptcp: drop tx skb cache") 4e14867d5e91 ("mptcp: tune re-injections for csum enabled mode") 208e8f66926c ("mptcp: receive checksum for MP_CAPABLE with data") 0625118115cf ("mptcp: add csum_reqd in mptcp_options_received") c5b39e26d003 ("mptcp: send out checksum for DSS")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e32d262c89e2b22cb0640223f953b548617ed8a6 Mon Sep 17 00:00:00 2001 From: Paolo Abeni pabeni@redhat.com Date: Tue, 8 Oct 2024 13:04:52 +0200 Subject: [PATCH] mptcp: handle consistently DSS corruption

Bugged peer implementation can send corrupted DSS options, consistently hitting a few warning in the data path. Use DEBUG_NET assertions, to avoid the splat on some builds and handle consistently the error, dumping related MIBs and performing fallback and/or reset according to the subflow type.

Fixes: 6771bfd9ee24 ("mptcp: update mptcp ack sequence from work queue") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://patch.msgid.link/20241008-net-mptcp-fallback-fixes-v1-1-c6fb8e93e551... Signed-off-by: Jakub Kicinski kuba@kernel.org

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c index 38c2efc82b94..ad88bd3c58df 100644 --- a/net/mptcp/mib.c +++ b/net/mptcp/mib.c @@ -32,6 +32,8 @@ static const struct snmp_mib mptcp_snmp_list[] = { SNMP_MIB_ITEM("MPJoinSynTxBindErr", MPTCP_MIB_JOINSYNTXBINDERR), SNMP_MIB_ITEM("MPJoinSynTxConnectErr", MPTCP_MIB_JOINSYNTXCONNECTERR), SNMP_MIB_ITEM("DSSNotMatching", MPTCP_MIB_DSSNOMATCH), + SNMP_MIB_ITEM("DSSCorruptionFallback", MPTCP_MIB_DSSCORRUPTIONFALLBACK), + SNMP_MIB_ITEM("DSSCorruptionReset", MPTCP_MIB_DSSCORRUPTIONRESET), SNMP_MIB_ITEM("InfiniteMapTx", MPTCP_MIB_INFINITEMAPTX), SNMP_MIB_ITEM("InfiniteMapRx", MPTCP_MIB_INFINITEMAPRX), SNMP_MIB_ITEM("DSSNoMatchTCP", MPTCP_MIB_DSSTCPMISMATCH), diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h index c8ffe18a8722..3206cdda8bb1 100644 --- a/net/mptcp/mib.h +++ b/net/mptcp/mib.h @@ -27,6 +27,8 @@ enum linux_mptcp_mib_field { MPTCP_MIB_JOINSYNTXBINDERR, /* Not able to bind() the address when sending a SYN + MP_JOIN */ MPTCP_MIB_JOINSYNTXCONNECTERR, /* Not able to connect() when sending a SYN + MP_JOIN */ MPTCP_MIB_DSSNOMATCH, /* Received a new mapping that did not match the previous one */ + MPTCP_MIB_DSSCORRUPTIONFALLBACK,/* DSS corruption detected, fallback */ + MPTCP_MIB_DSSCORRUPTIONRESET, /* DSS corruption detected, MPJ subflow reset */ MPTCP_MIB_INFINITEMAPTX, /* Sent an infinite mapping */ MPTCP_MIB_INFINITEMAPRX, /* Received an infinite mapping */ MPTCP_MIB_DSSTCPMISMATCH, /* DSS-mapping did not map with TCP's sequence numbers */ diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index c2317919fc14..6d0e201c3eb2 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -620,6 +620,18 @@ static bool mptcp_check_data_fin(struct sock *sk) return ret; }

+static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk) +{ + if (READ_ONCE(msk->allow_infinite_fallback)) { + MPTCP_INC_STATS(sock_net(ssk), + MPTCP_MIB_DSSCORRUPTIONFALLBACK); + mptcp_do_fallback(ssk); + } else { + MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSCORRUPTIONRESET); + mptcp_subflow_reset(ssk); + } +} + static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, struct sock *ssk, unsigned int *bytes) @@ -692,10 +704,16 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, moved += len; seq += len;

- if (WARN_ON_ONCE(map_remaining < len)) - break; + if (unlikely(map_remaining < len)) { + DEBUG_NET_WARN_ON_ONCE(1); + mptcp_dss_corruption(msk, ssk); + } } else { - WARN_ON_ONCE(!fin); + if (unlikely(!fin)) { + DEBUG_NET_WARN_ON_ONCE(1); + mptcp_dss_corruption(msk, ssk); + } + sk_eat_skb(ssk, skb); done = true; } diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 1040b3b9696b..e1046a696ab5 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -975,8 +975,10 @@ static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) unsigned int skb_consumed;

skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; - if (WARN_ON_ONCE(skb_consumed >= skb->len)) + if (unlikely(skb_consumed >= skb->len)) { + DEBUG_NET_WARN_ON_ONCE(1); return true; + }

return skb->len - skb_consumed <= subflow->map_data_len - mptcp_subflow_get_map_offset(subflow);