From e69019ec7aa6bd40ab23659e4b97cdb094ab7a79 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 15 Jun 2021 18:01:50 +0200 Subject: payload: do not remove icmp echo dependency "icmp type echo-request icmp id 2" and "icmp id 2" are not the same, the latter gains an implicit dependency on both echo-request and echo-reply. Change payload dependency tracking to not store dependency in case the value type is ICMP(6)_ECHO(REPLY). Signed-off-by: Florian Westphal --- src/payload.c | 61 ++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 24 deletions(-) (limited to 'src/payload.c') diff --git a/src/payload.c b/src/payload.c index cfa95224..97b60713 100644 --- a/src/payload.c +++ b/src/payload.c @@ -98,12 +98,16 @@ static void payload_expr_pctx_update(struct proto_ctx *ctx, desc = proto_find_upper(base, proto); if (!desc) { - if (base == &proto_icmp || base == &proto_icmp6) { + if (base == &proto_icmp) { /* proto 0 is ECHOREPLY, just pretend its ECHO. * Not doing this would need an additional marker * bit to tell when icmp.type was set. */ ctx->th_dep.icmp.type = proto ? proto : ICMP_ECHO; + } else if (base == &proto_icmp6) { + if (proto == ICMP6_ECHO_REPLY) + proto = ICMP6_ECHO_REQUEST; + ctx->th_dep.icmp.type = proto; } return; } @@ -554,33 +558,39 @@ void payload_dependency_reset(struct payload_dep_ctx *ctx) memset(ctx, 0, sizeof(*ctx)); } -static uint8_t icmp_get_type(const struct proto_desc *desc, uint8_t value) +static bool payload_dependency_store_icmp_type(struct payload_dep_ctx *ctx, + const struct stmt *stmt) { - if (desc == &proto_icmp && value == 0) - return ICMP_ECHO; + struct expr *dep = stmt->expr; + const struct proto_desc *desc; + const struct expr *right; + uint8_t type; - return value; -} + if (dep->left->etype != EXPR_PAYLOAD) + return false; -static uint8_t icmp_get_dep_type(const struct proto_desc *desc, struct expr *right) -{ - if (right->etype == EXPR_VALUE && right->len == BITS_PER_BYTE) - return icmp_get_type(desc, mpz_get_uint8(right->value)); + right = dep->right; + if (right->etype != EXPR_VALUE || right->len != BITS_PER_BYTE) + return false; - return 0; -} + desc = dep->left->payload.desc; + if (desc == &proto_icmp) { + type = mpz_get_uint8(right->value); -static void payload_dependency_store_icmp_type(struct payload_dep_ctx *ctx) -{ - struct expr *dep = ctx->pdep->expr; - const struct proto_desc *desc; + if (type == ICMP_ECHOREPLY) + type = ICMP_ECHO; - if (dep->left->etype != EXPR_PAYLOAD) - return; + ctx->icmp_type = type; - desc = dep->left->payload.desc; - if (desc == &proto_icmp || desc == &proto_icmp6) - ctx->icmp_type = icmp_get_dep_type(dep->left->payload.desc, dep->right); + return type == ICMP_ECHO; + } else if (desc == &proto_icmp6) { + type = mpz_get_uint8(right->value); + + ctx->icmp_type = type; + return type == ICMP6_ECHO_REQUEST || type == ICMP6_ECHO_REPLY; + } + + return false; } /** @@ -593,10 +603,13 @@ static void payload_dependency_store_icmp_type(struct payload_dep_ctx *ctx) void payload_dependency_store(struct payload_dep_ctx *ctx, struct stmt *stmt, enum proto_bases base) { - ctx->pbase = base + 1; - ctx->pdep = stmt; + bool ignore_dep = payload_dependency_store_icmp_type(ctx, stmt); + + if (ignore_dep) + return; - payload_dependency_store_icmp_type(ctx); + ctx->pdep = stmt; + ctx->pbase = base + 1; } /** -- cgit v1.2.3