From 49479aa12a158001bf1e4104b248e533f5038cf3 Mon Sep 17 00:00:00 2001 From: Arturo Borrero Date: Mon, 19 Jan 2015 14:28:07 +0100 Subject: ebtables-compat: add 'ip' match extension This patch adds the 'ip' match extension to ebtables-compat. It involves adapting old ebtables extension code to the xtables-compat environment. For testing: % sudo ebtables-compat -p 0x0800 --ip-src 1.1.1.1 -j ACCEPT The patch includes a cached copy of the extension kernel header. Signed-off-by: Arturo Borrero Gonzalez Signed-off-by: Pablo Neira Ayuso --- extensions/libebt_ip.c | 326 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 326 insertions(+) create mode 100644 extensions/libebt_ip.c (limited to 'extensions') diff --git a/extensions/libebt_ip.c b/extensions/libebt_ip.c new file mode 100644 index 00000000..ffb7ed66 --- /dev/null +++ b/extensions/libebt_ip.c @@ -0,0 +1,326 @@ +/* ebt_ip + * + * Authors: + * Bart De Schuymer + * + * Changes: + * added ip-sport and ip-dport; parsing of port arguments is + * based on code from iptables-1.2.7a + * Innominate Security Technologies AG + * September, 2002 + * + * Adapted by Arturo Borrero Gonzalez + * to use libxtables for ebtables-compat in 2015. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define IP_SOURCE '1' +#define IP_DEST '2' +#define IP_EBT_TOS '3' /* include/bits/in.h seems to already define IP_TOS */ +#define IP_PROTO '4' +#define IP_SPORT '5' +#define IP_DPORT '6' + +static const struct option brip_opts[] = { + { .name = "ip-source", .has_arg = true, .val = IP_SOURCE }, + { .name = "ip-src", .has_arg = true, .val = IP_SOURCE }, + { .name = "ip-destination", .has_arg = true, .val = IP_DEST }, + { .name = "ip-dst", .has_arg = true, .val = IP_DEST }, + { .name = "ip-tos", .has_arg = true, .val = IP_EBT_TOS }, + { .name = "ip-protocol", .has_arg = true, .val = IP_PROTO }, + { .name = "ip-proto", .has_arg = true, .val = IP_PROTO }, + { .name = "ip-source-port", .has_arg = true, .val = IP_SPORT }, + { .name = "ip-sport", .has_arg = true, .val = IP_SPORT }, + { .name = "ip-destination-port",.has_arg = true, .val = IP_DPORT }, + { .name = "ip-dport", .has_arg = true, .val = IP_DPORT }, + XT_GETOPT_TABLEEND, +}; + +static void brip_print_help(void) +{ + printf( +"ip options:\n" +"--ip-src [!] address[/mask]: ip source specification\n" +"--ip-dst [!] address[/mask]: ip destination specification\n" +"--ip-tos [!] tos : ip tos specification\n" +"--ip-proto [!] protocol : ip protocol specification\n" +"--ip-sport [!] port[:port] : tcp/udp source port or port range\n" +"--ip-dport [!] port[:port] : tcp/udp destination port or port range\n"); +} + +static void brip_init(struct xt_entry_match *match) +{ + struct ebt_ip_info *info = (struct ebt_ip_info *)match->data; + + info->invflags = 0; + info->bitmask = 0; +} + +static void +parse_port_range(const char *protocol, const char *portstring, uint16_t *ports) +{ + char *buffer; + char *cp; + + buffer = strdup(portstring); + if ((cp = strchr(buffer, ':')) == NULL) + ports[0] = ports[1] = xtables_parse_port(buffer, NULL); + else { + *cp = '\0'; + cp++; + + ports[0] = buffer[0] ? xtables_parse_port(buffer, NULL) : 0; + ports[1] = cp[0] ? xtables_parse_port(cp, NULL) : 0xFFFF; + + if (ports[0] > ports[1]) + xtables_error(PARAMETER_PROBLEM, + "invalid portrange (min > max)"); + } + free(buffer); +} + +/* original code from ebtables: useful_functions.c */ +static int undot_ip(char *ip, unsigned char *ip2) +{ + char *p, *q, *end; + long int onebyte; + int i; + char buf[20]; + + strncpy(buf, ip, sizeof(buf) - 1); + + p = buf; + for (i = 0; i < 3; i++) { + if ((q = strchr(p, '.')) == NULL) + return -1; + *q = '\0'; + onebyte = strtol(p, &end, 10); + if (*end != '\0' || onebyte > 255 || onebyte < 0) + return -1; + ip2[i] = (unsigned char)onebyte; + p = q + 1; + } + + onebyte = strtol(p, &end, 10); + if (*end != '\0' || onebyte > 255 || onebyte < 0) + return -1; + ip2[3] = (unsigned char)onebyte; + + return 0; +} + +static int ip_mask(char *mask, unsigned char *mask2) +{ + char *end; + long int bits; + uint32_t mask22; + + if (undot_ip(mask, mask2)) { + /* not the /a.b.c.e format, maybe the /x format */ + bits = strtol(mask, &end, 10); + if (*end != '\0' || bits > 32 || bits < 0) + return -1; + if (bits != 0) { + mask22 = htonl(0xFFFFFFFF << (32 - bits)); + memcpy(mask2, &mask22, 4); + } else { + mask22 = 0xFFFFFFFF; + memcpy(mask2, &mask22, 4); + } + } + return 0; +} + +static void ebt_parse_ip_address(char *address, uint32_t *addr, uint32_t *msk) +{ + char *p; + + /* first the mask */ + if ((p = strrchr(address, '/')) != NULL) { + *p = '\0'; + if (ip_mask(p + 1, (unsigned char *)msk)) { + xtables_error(PARAMETER_PROBLEM, + "Problem with the IP mask '%s'", p + 1); + return; + } + } else + *msk = 0xFFFFFFFF; + + if (undot_ip(address, (unsigned char *)addr)) { + xtables_error(PARAMETER_PROBLEM, + "Problem with the IP address '%s'", address); + return; + } + *addr = *addr & *msk; +} + +static int +brip_parse(int c, char **argv, int invert, unsigned int *flags, + const void *entry, struct xt_entry_match **match) +{ + struct ebt_ip_info *info = (struct ebt_ip_info *)(*match)->data; + + switch (c) { + case IP_SOURCE: + if (invert) + info->invflags |= EBT_IP_SOURCE; + ebt_parse_ip_address(optarg, &info->saddr, &info->smsk); + info->bitmask |= EBT_IP_SOURCE; + break; + case IP_DEST: + if (invert) + info->invflags |= EBT_IP_DEST; + ebt_parse_ip_address(optarg, &info->daddr, &info->dmsk); + info->bitmask |= EBT_IP_DEST; + break; + case IP_SPORT: + if (invert) + info->invflags |= EBT_IP_SPORT; + parse_port_range(NULL, optarg, info->sport); + info->bitmask |= EBT_IP_SPORT; + break; + case IP_DPORT: + if (invert) + info->invflags |= EBT_IP_DPORT; + parse_port_range(NULL, optarg, info->dport); + info->bitmask |= EBT_IP_DPORT; + break; + case IP_EBT_TOS: + if (invert) + info->invflags |= EBT_IP_TOS; + if (!xtables_strtoul(optarg, NULL, (uintmax_t *)&info->tos, + 0, 255)) + xtables_error(PARAMETER_PROBLEM, + "Problem with specified IP tos"); + info->bitmask |= EBT_IP_TOS; + break; + case IP_PROTO: + if (invert) + info->invflags |= EBT_IP_PROTO; + info->protocol = xtables_parse_protocol(optarg); + if (info->protocol == -1) + xtables_error(PARAMETER_PROBLEM, + "Unknown specified IP protocol - %s", + optarg); + info->bitmask |= EBT_IP_PROTO; + break; + default: + return 0; + } + return 1; +} + +static void brip_final_check(unsigned int flags) +{ +/* struct ebt_ip_info *ipinfo = (struct ebt_ip_info *)match->data; + + if (entry->ethproto != ETH_P_IP || entry->invflags & EBT_IPROTO) { + ebt_print_error("For IP filtering the protocol must be " + "specified as IPv4"); + } else if (info->bitmask & (EBT_IP_SPORT|EBT_IP_DPORT) && + (!(info->bitmask & EBT_IP_PROTO) || + info->invflags & EBT_IP_PROTO || + (info->protocol!=IPPROTO_TCP && + info->protocol!=IPPROTO_UDP && + info->protocol!=IPPROTO_SCTP && + info->protocol!=IPPROTO_DCCP))) + ebt_print_error("For port filtering the IP protocol must be " + "either 6 (tcp), 17 (udp), 33 (dccp) or " + "132 (sctp)"); +*/ + if (!flags) + xtables_error(PARAMETER_PROBLEM, + "You must specify proper arguments"); +} + +static void print_port_range(uint16_t *ports) +{ + if (ports[0] == ports[1]) + printf("%d ", ports[0]); + else + printf("%d:%d ", ports[0], ports[1]); +} + +static void brip_print(const void *ip, const struct xt_entry_match *match, + int numeric) +{ + struct ebt_ip_info *info = (struct ebt_ip_info *)match->data; + struct in_addr *addrp, *maskp; + + if (info->bitmask & EBT_IP_SOURCE) { + printf("--ip-src "); + if (info->invflags & EBT_IP_SOURCE) + printf("! "); + addrp = (struct in_addr *)&info->saddr; + maskp = (struct in_addr *)&info->smsk; + printf("%s%s ", xtables_ipaddr_to_numeric(addrp), + xtables_ipmask_to_numeric(maskp)); + } + if (info->bitmask & EBT_IP_DEST) { + printf("--ip-dst "); + if (info->invflags & EBT_IP_DEST) + printf("! "); + addrp = (struct in_addr *)&info->daddr; + maskp = (struct in_addr *)&info->dmsk; + printf("%s%s ", xtables_ipaddr_to_numeric(addrp), + xtables_ipmask_to_numeric(maskp)); + } + if (info->bitmask & EBT_IP_TOS) { + printf("--ip-tos "); + if (info->invflags & EBT_IP_TOS) + printf("! "); + printf("0x%02X ", info->tos); + } + if (info->bitmask & EBT_IP_PROTO) { + struct protoent *pe; + + printf("--ip-proto "); + if (info->invflags & EBT_IP_PROTO) + printf("! "); + pe = getprotobynumber(info->protocol); + if (pe == NULL) { + printf("%d ", info->protocol); + } else { + printf("%s ", pe->p_name); + } + } + if (info->bitmask & EBT_IP_SPORT) { + printf("--ip-sport "); + if (info->invflags & EBT_IP_SPORT) + printf("! "); + print_port_range(info->sport); + } + if (info->bitmask & EBT_IP_DPORT) { + printf("--ip-dport "); + if (info->invflags & EBT_IP_DPORT) + printf("! "); + print_port_range(info->dport); + } +} + +static struct xtables_match brip_match = { + .name = "ip", + .revision = 0, + .version = XTABLES_VERSION, + .family = NFPROTO_BRIDGE, + .size = XT_ALIGN(sizeof(struct ebt_ip_info)), + .userspacesize = XT_ALIGN(sizeof(struct ebt_ip_info)), + .init = brip_init, + .help = brip_print_help, + .parse = brip_parse, + .final_check = brip_final_check, + .print = brip_print, + .extra_opts = brip_opts, +}; + +void _init(void) +{ + xtables_register_match(&brip_match); +} -- cgit v1.2.3