From 9a5574e2d4e9c9cb5d6382be03a7eccfa8663a15 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 15 Jun 2021 18:01:49 +0200 Subject: netlink_delinearize: add missing icmp id/sequence support Pablo reports following input and output: in: icmpv6 id 1 out: icmpv6 type { echo-request, echo-reply } icmpv6 parameter-problem 65536/16 Reason is that icmp fields overlap, decoding of the correct name requires check of the icmpv6 type. This only works for equality tests, for instance in: icmpv6 type echo-request icmpv6 id 1 will be listed as "icmpv6 id 1" (which is not correct either, since the input only matches on echo-request). with this patch, output of 'icmpv6 id 1' is icmpv6 type { echo-request, echo-reply } icmpv6 id 1 The second problem, the removal of a single check (request OR reply), is resolved in the followup patch. Signed-off-by: Florian Westphal --- src/netlink_delinearize.c | 68 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 65 insertions(+), 3 deletions(-) (limited to 'src') diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 5c80397d..952e2be5 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -1819,9 +1819,6 @@ static void payload_match_expand(struct rule_pp_ctx *ctx, enum proto_bases base = left->payload.base; bool stacked; - if (ctx->pdctx.icmp_type) - ctx->pctx.th_dep.icmp.type = ctx->pdctx.icmp_type; - payload_expr_expand(&list, left, &ctx->pctx); list_for_each_entry(left, &list, list) { @@ -1868,6 +1865,58 @@ static void payload_match_expand(struct rule_pp_ctx *ctx, ctx->stmt = NULL; } +static void payload_icmp_check(struct rule_pp_ctx *rctx, struct expr *expr, const struct expr *value) +{ + const struct proto_hdr_template *tmpl; + const struct proto_desc *desc; + uint8_t icmp_type; + unsigned int i; + + assert(expr->etype == EXPR_PAYLOAD); + assert(value->etype == EXPR_VALUE); + + if (expr->payload.base != PROTO_BASE_TRANSPORT_HDR) + return; + + /* icmp(v6) type is 8 bit, if value is smaller or larger, this is not + * a protocol dependency. + */ + if (expr->len != 8 || value->len != 8 || rctx->pctx.th_dep.icmp.type) + return; + + desc = rctx->pctx.protocol[expr->payload.base].desc; + if (desc == NULL) + return; + + /* not icmp? ignore. */ + if (desc != &proto_icmp && desc != &proto_icmp6) + return; + + assert(desc->base == expr->payload.base); + + icmp_type = mpz_get_uint8(value->value); + + for (i = 1; i < array_size(desc->templates); i++) { + tmpl = &desc->templates[i]; + + if (tmpl->len == 0) + return; + + if (tmpl->offset != expr->payload.offset || + tmpl->len != expr->len) + continue; + + /* Matches but doesn't load a protocol key -> ignore. */ + if (desc->protocol_key != i) + return; + + expr->payload.desc = desc; + expr->payload.tmpl = tmpl; + rctx->pctx.th_dep.icmp.type = icmp_type; + return; + } +} + static void payload_match_postprocess(struct rule_pp_ctx *ctx, struct expr *expr, struct expr *payload) @@ -1883,6 +1932,19 @@ static void payload_match_postprocess(struct rule_pp_ctx *ctx, if (expr->right->etype == EXPR_VALUE) { payload_match_expand(ctx, expr, payload); break; + } else if (expr->right->etype == EXPR_SET_REF) { + struct set *set = expr->right->set; + + if (set_is_anonymous(set->flags) && + !list_empty(&set->init->expressions)) { + struct expr *elem; + + elem = list_first_entry(&set->init->expressions, struct expr, list); + + if (elem->etype == EXPR_SET_ELEM && + elem->key->etype == EXPR_VALUE) + payload_icmp_check(ctx, payload, elem->key); + } } /* Fall through */ default: -- cgit v1.2.3