From 448d1ff5807a52ec34759a6dddd348c5f3e96704 Mon Sep 17 00:00:00 2001 From: Phil Sutter 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 (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 -- 2.40.0