From b1c5270bdf35138d7459349df487e1c9e18c4c32 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 2 Sep 2021 16:51:15 +0200 Subject: libxtables: Fix guided option parser for use with arptables With an unexpected value in afinfo->family, guided option parser was rather useless when called from arptables extensions. Introduce afinfo_family() wrapper to sanitize at least NFPROTO_ARP value. Signed-off-by: Phil Sutter --- libxtables/xtoptions.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'libxtables') diff --git a/libxtables/xtoptions.c b/libxtables/xtoptions.c index 0667315c..25540f8b 100644 --- a/libxtables/xtoptions.c +++ b/libxtables/xtoptions.c @@ -65,6 +65,19 @@ static const size_t xtopt_psize[] = { [XTTYPE_ETHERMAC] = sizeof(uint8_t[6]), }; +/** + * Return a sanitized afinfo->family value, covering for NFPROTO_ARP + */ +static uint8_t afinfo_family(void) +{ + switch (afinfo->family) { + case NFPROTO_ARP: + return NFPROTO_IPV4; + default: + return afinfo->family; + } +} + /** * Creates getopt options from the x6-style option map, and assigns each a * getopt id. @@ -461,7 +474,7 @@ static socklen_t xtables_sa_hostlen(unsigned int afproto) */ static void xtopt_parse_host(struct xt_option_call *cb) { - struct addrinfo hints = {.ai_family = afinfo->family}; + struct addrinfo hints = {.ai_family = afinfo_family()}; unsigned int adcount = 0; struct addrinfo *res, *p; int ret; @@ -472,7 +485,7 @@ static void xtopt_parse_host(struct xt_option_call *cb) "getaddrinfo: %s\n", gai_strerror(ret)); memset(&cb->val.hmask, 0xFF, sizeof(cb->val.hmask)); - cb->val.hlen = (afinfo->family == NFPROTO_IPV4) ? 32 : 128; + cb->val.hlen = (afinfo_family() == NFPROTO_IPV4) ? 32 : 128; for (p = res; p != NULL; p = p->ai_next) { if (adcount == 0) { @@ -615,7 +628,7 @@ static void xtopt_parse_mport(struct xt_option_call *cb) static int xtopt_parse_mask(struct xt_option_call *cb) { - struct addrinfo hints = {.ai_family = afinfo->family, + struct addrinfo hints = {.ai_family = afinfo_family(), .ai_flags = AI_NUMERICHOST }; struct addrinfo *res; int ret; @@ -627,7 +640,7 @@ static int xtopt_parse_mask(struct xt_option_call *cb) memcpy(&cb->val.hmask, xtables_sa_host(res->ai_addr, res->ai_family), xtables_sa_hostlen(res->ai_family)); - switch(afinfo->family) { + switch(afinfo_family()) { case AF_INET: cb->val.hlen = xtables_ipmask_to_cidr(&cb->val.hmask.in); break; @@ -649,7 +662,7 @@ static void xtopt_parse_plen(struct xt_option_call *cb) const struct xt_option_entry *entry = cb->entry; unsigned int prefix_len = 128; /* happiness is a warm gcc */ - cb->val.hlen = (afinfo->family == NFPROTO_IPV4) ? 32 : 128; + cb->val.hlen = (afinfo_family() == NFPROTO_IPV4) ? 32 : 128; if (!xtables_strtoui(cb->arg, NULL, &prefix_len, 0, cb->val.hlen)) { /* Is this mask expressed in full format? e.g. 255.255.255.0 */ if (xtopt_parse_mask(cb)) -- cgit v1.2.3