From: Paolo Abeni pabeni@redhat.com
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 --- net/mptcp/mib.c | 2 ++ net/mptcp/mib.h | 2 ++ net/mptcp/protocol.c | 24 +++++++++++++++++++++--- net/mptcp/subflow.c | 4 +++- 4 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c index 38c2efc82b948d9afd35c4d5bcd45d9e5422a88d..ad88bd3c58dffed8335eedb43ca6290418e3c4f4 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 c8ffe18a872217afa24e3af212fe90a3fb8d1c7f..3206cdda8bb1067f9a8354fd45deed86b67ac7da 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 c2317919fc148a67a81ded795359bd613c9b0dff..6d0e201c3eb26aa6ca0ff27e5a65cb6f911012f2 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 1040b3b9696b74b12c1f8c027e5a323c558900f0..e1046a696ab5c79a2cef79870eb79637b432fcd5 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);