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iptables/SOURCES/0056-extensions-sctp-Translate-chunk-types-option.patch

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import iptables-1.8.4-20.el8
2021-10-06 12:08:52 +00:00
From 48f38c4224f31d19176df83539501292fcc6092b Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Tue, 4 May 2021 16:26:42 +0200
Subject: [PATCH] extensions: sctp: Translate --chunk-types option
The translation is not fully complete as it is not possible to map 'any'
match type into nft syntax with a single rule. Also, 'only' match type
translation is a bit poor as it explicitly lists all chunk types that
are supposed to be missing.
Signed-off-by: Phil Sutter <phil@nwl.cc>
(cherry picked from commit 5818be177110a09120dd8fe4bd2533acbf8da301)
---
extensions/libxt_sctp.c | 91 ++++++++++++++++++++++++++++--------
extensions/libxt_sctp.txlate | 6 +++
2 files changed, 78 insertions(+), 19 deletions(-)
diff --git a/extensions/libxt_sctp.c b/extensions/libxt_sctp.c
index ee4e99ebf11bf..5d8ab85cacf42 100644
--- a/extensions/libxt_sctp.c
+++ b/extensions/libxt_sctp.c
@@ -92,28 +92,29 @@ struct sctp_chunk_names {
const char *name;
unsigned int chunk_type;
const char *valid_flags;
+ const char *nftname;
};
/*'ALL' and 'NONE' will be treated specially. */
static const struct sctp_chunk_names sctp_chunk_names[]
-= { { .name = "DATA", .chunk_type = 0, .valid_flags = "----IUBE"},
- { .name = "INIT", .chunk_type = 1, .valid_flags = "--------"},
- { .name = "INIT_ACK", .chunk_type = 2, .valid_flags = "--------"},
- { .name = "SACK", .chunk_type = 3, .valid_flags = "--------"},
- { .name = "HEARTBEAT", .chunk_type = 4, .valid_flags = "--------"},
- { .name = "HEARTBEAT_ACK", .chunk_type = 5, .valid_flags = "--------"},
- { .name = "ABORT", .chunk_type = 6, .valid_flags = "-------T"},
- { .name = "SHUTDOWN", .chunk_type = 7, .valid_flags = "--------"},
- { .name = "SHUTDOWN_ACK", .chunk_type = 8, .valid_flags = "--------"},
- { .name = "ERROR", .chunk_type = 9, .valid_flags = "--------"},
- { .name = "COOKIE_ECHO", .chunk_type = 10, .valid_flags = "--------"},
- { .name = "COOKIE_ACK", .chunk_type = 11, .valid_flags = "--------"},
- { .name = "ECN_ECNE", .chunk_type = 12, .valid_flags = "--------"},
- { .name = "ECN_CWR", .chunk_type = 13, .valid_flags = "--------"},
- { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14, .valid_flags = "-------T"},
- { .name = "ASCONF", .chunk_type = 193, .valid_flags = "--------"},
- { .name = "ASCONF_ACK", .chunk_type = 128, .valid_flags = "--------"},
- { .name = "FORWARD_TSN", .chunk_type = 192, .valid_flags = "--------"},
+= { { .name = "DATA", .chunk_type = 0, .valid_flags = "----IUBE", .nftname = "data" },
+ { .name = "INIT", .chunk_type = 1, .valid_flags = "--------", .nftname = "init" },
+ { .name = "INIT_ACK", .chunk_type = 2, .valid_flags = "--------", .nftname = "init-ack" },
+ { .name = "SACK", .chunk_type = 3, .valid_flags = "--------", .nftname = "sack" },
+ { .name = "HEARTBEAT", .chunk_type = 4, .valid_flags = "--------", .nftname = "heartbeat" },
+ { .name = "HEARTBEAT_ACK", .chunk_type = 5, .valid_flags = "--------", .nftname = "heartbeat-ack" },
+ { .name = "ABORT", .chunk_type = 6, .valid_flags = "-------T", .nftname = "abort" },
+ { .name = "SHUTDOWN", .chunk_type = 7, .valid_flags = "--------", .nftname = "shutdown" },
+ { .name = "SHUTDOWN_ACK", .chunk_type = 8, .valid_flags = "--------", .nftname = "shutdown-ack" },
+ { .name = "ERROR", .chunk_type = 9, .valid_flags = "--------", .nftname = "error" },
+ { .name = "COOKIE_ECHO", .chunk_type = 10, .valid_flags = "--------", .nftname = "cookie-echo" },
+ { .name = "COOKIE_ACK", .chunk_type = 11, .valid_flags = "--------", .nftname = "cookie-ack" },
+ { .name = "ECN_ECNE", .chunk_type = 12, .valid_flags = "--------", .nftname = "ecne" },
+ { .name = "ECN_CWR", .chunk_type = 13, .valid_flags = "--------", .nftname = "cwr" },
+ { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14, .valid_flags = "-------T", .nftname = "shutdown-complete" },
+ { .name = "ASCONF", .chunk_type = 193, .valid_flags = "--------", .nftname = "asconf" },
+ { .name = "ASCONF_ACK", .chunk_type = 128, .valid_flags = "--------", .nftname = "asconf-ack" },
+ { .name = "FORWARD_TSN", .chunk_type = 192, .valid_flags = "--------", .nftname = "forward-tsn" },
};
static void
@@ -485,12 +486,52 @@ static void sctp_save(const void *ip, const struct xt_entry_match *match)
}
}
+static const char *sctp_xlate_chunk(struct xt_xlate *xl, const char *space,
+ const struct xt_sctp_info *einfo,
+ const struct sctp_chunk_names *scn)
+{
+ bool inv = einfo->invflags & XT_SCTP_CHUNK_TYPES;
+ const struct xt_sctp_flag_info *flag_info = NULL;
+ int i;
+
+ if (!scn->nftname)
+ return space;
+
+ if (!SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, scn->chunk_type)) {
+ if (einfo->chunk_match_type != SCTP_CHUNK_MATCH_ONLY)
+ return space;
+
+ xt_xlate_add(xl, "%ssctp chunk %s %s", space,
+ scn->nftname, inv ? "exists" : "missing");
+ return " ";
+ }
+
+ for (i = 0; i < einfo->flag_count; i++) {
+ if (einfo->flag_info[i].chunktype == scn->chunk_type) {
+ flag_info = &einfo->flag_info[i];
+ break;
+ }
+ }
+
+ if (!flag_info) {
+ xt_xlate_add(xl, "%ssctp chunk %s %s", space,
+ scn->nftname, inv ? "missing" : "exists");
+ return " ";
+ }
+
+ xt_xlate_add(xl, "%ssctp chunk %s flags & 0x%x %s 0x%x", space,
+ scn->nftname, flag_info->flag_mask,
+ inv ? "!=" : "==", flag_info->flag);
+
+ return " ";
+}
+
static int sctp_xlate(struct xt_xlate *xl,
const struct xt_xlate_mt_params *params)
{
const struct xt_sctp_info *einfo =
(const struct xt_sctp_info *)params->match->data;
- char *space = "";
+ const char *space = "";
if (!einfo->flags)
return 0;
@@ -516,6 +557,18 @@ static int sctp_xlate(struct xt_xlate *xl,
xt_xlate_add(xl, "%ssctp dport%s %u", space,
einfo->invflags & XT_SCTP_DEST_PORTS ? " !=" : "",
einfo->dpts[0]);
+ space = " ";
+ }
+
+ if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
+ int i;
+
+ if (einfo->chunk_match_type == SCTP_CHUNK_MATCH_ANY)
+ return 0;
+
+ for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); i++)
+ space = sctp_xlate_chunk(xl, space, einfo,
+ &sctp_chunk_names[i]);
}
return 1;
diff --git a/extensions/libxt_sctp.txlate b/extensions/libxt_sctp.txlate
index 0d6c59e183675..bb817525db8d8 100644
--- a/extensions/libxt_sctp.txlate
+++ b/extensions/libxt_sctp.txlate
@@ -36,3 +36,9 @@ nft add rule ip filter INPUT sctp sport 50 sctp dport != 80-100 counter accept
iptables-translate -A INPUT -p sctp --dport 80 ! --sport 50:55 -j ACCEPT
nft add rule ip filter INPUT sctp sport != 50-55 sctp dport 80 counter accept
+
+iptables-translate -A INPUT -p sctp --chunk-types all INIT,DATA:iUbE,SACK,ABORT:T -j ACCEPT
+nft add rule ip filter INPUT sctp chunk data flags & 0xf == 0x5 sctp chunk init exists sctp chunk sack exists sctp chunk abort flags & 0x1 == 0x1 counter accept
+
+iptables-translate -A INPUT -p sctp --chunk-types only SHUTDOWN_COMPLETE -j ACCEPT
+nft add rule ip filter INPUT sctp chunk data missing sctp chunk init missing sctp chunk init-ack missing sctp chunk sack missing sctp chunk heartbeat missing sctp chunk heartbeat-ack missing sctp chunk abort missing sctp chunk shutdown missing sctp chunk shutdown-ack missing sctp chunk error missing sctp chunk cookie-echo missing sctp chunk cookie-ack missing sctp chunk ecne missing sctp chunk cwr missing sctp chunk shutdown-complete exists sctp chunk asconf missing sctp chunk asconf-ack missing sctp chunk forward-tsn missing counter accept
--
2.31.1
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