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author | 2020-08-18 16:15:58 +0200 | |
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committer | 2020-08-20 14:13:49 +0200 | |
commit | cc5453a5b7e90c39f713091a7ebc53c1f87d1700 (patch) | |
tree | 631ff062cc6b96c5b2cc723a395e79864656580a /net/netfilter | |
parent | net: gemini: Fix missing free_netdev() in error path of gemini_ethernet_port_... (diff) | |
download | linux-cc5453a5b7e90c39f713091a7ebc53c1f87d1700.tar.gz linux-cc5453a5b7e90c39f713091a7ebc53c1f87d1700.tar.bz2 linux-cc5453a5b7e90c39f713091a7ebc53c1f87d1700.zip |
netfilter: conntrack: allow sctp hearbeat after connection re-use
If an sctp connection gets re-used, heartbeats are flagged as invalid
because their vtag doesn't match.
Handle this in a similar way as TCP conntrack when it suspects that the
endpoints and conntrack are out-of-sync.
When a HEARTBEAT request fails its vtag validation, flag this in the
conntrack state and accept the packet.
When a HEARTBEAT_ACK is received with an invalid vtag in the reverse
direction after we allowed such a HEARTBEAT through, assume we are
out-of-sync and re-set the vtag info.
v2: remove left-over snippet from an older incarnation that moved
new_state/old_state assignments, thats not needed so keep that
as-is.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r-- | net/netfilter/nf_conntrack_proto_sctp.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c index 4f897b14b606..810cca24b399 100644 --- a/net/netfilter/nf_conntrack_proto_sctp.c +++ b/net/netfilter/nf_conntrack_proto_sctp.c @@ -62,6 +62,8 @@ static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = { [SCTP_CONNTRACK_HEARTBEAT_ACKED] = 210 SECS, }; +#define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1 + #define sNO SCTP_CONNTRACK_NONE #define sCL SCTP_CONNTRACK_CLOSED #define sCW SCTP_CONNTRACK_COOKIE_WAIT @@ -369,6 +371,7 @@ int nf_conntrack_sctp_packet(struct nf_conn *ct, u_int32_t offset, count; unsigned int *timeouts; unsigned long map[256 / sizeof(unsigned long)] = { 0 }; + bool ignore = false; if (sctp_error(skb, dataoff, state)) return -NF_ACCEPT; @@ -427,15 +430,39 @@ int nf_conntrack_sctp_packet(struct nf_conn *ct, /* Sec 8.5.1 (D) */ if (sh->vtag != ct->proto.sctp.vtag[dir]) goto out_unlock; - } else if (sch->type == SCTP_CID_HEARTBEAT || - sch->type == SCTP_CID_HEARTBEAT_ACK) { + } else if (sch->type == SCTP_CID_HEARTBEAT) { + if (ct->proto.sctp.vtag[dir] == 0) { + pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir); + ct->proto.sctp.vtag[dir] = sh->vtag; + } else if (sh->vtag != ct->proto.sctp.vtag[dir]) { + if (test_bit(SCTP_CID_DATA, map) || ignore) + goto out_unlock; + + ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED; + ct->proto.sctp.last_dir = dir; + ignore = true; + continue; + } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) { + ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED; + } + } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) { if (ct->proto.sctp.vtag[dir] == 0) { pr_debug("Setting vtag %x for dir %d\n", sh->vtag, dir); ct->proto.sctp.vtag[dir] = sh->vtag; } else if (sh->vtag != ct->proto.sctp.vtag[dir]) { - pr_debug("Verification tag check failed\n"); - goto out_unlock; + if (test_bit(SCTP_CID_DATA, map) || ignore) + goto out_unlock; + + if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 || + ct->proto.sctp.last_dir == dir) + goto out_unlock; + + ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED; + ct->proto.sctp.vtag[dir] = sh->vtag; + ct->proto.sctp.vtag[!dir] = 0; + } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) { + ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED; } } @@ -470,6 +497,10 @@ int nf_conntrack_sctp_packet(struct nf_conn *ct, } spin_unlock_bh(&ct->lock); + /* allow but do not refresh timeout */ + if (ignore) + return NF_ACCEPT; + timeouts = nf_ct_timeout_lookup(ct); if (!timeouts) timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts; |