diff options
Diffstat (limited to 'extensions/libxt_policy.c')
| -rw-r--r-- | extensions/libxt_policy.c | 513 |
1 files changed, 513 insertions, 0 deletions
diff --git a/extensions/libxt_policy.c b/extensions/libxt_policy.c new file mode 100644 index 0000000..a87ddd8 --- /dev/null +++ b/extensions/libxt_policy.c @@ -0,0 +1,513 @@ +/* Shared library add-on to iptables to add policy support. */ +#include <stdio.h> +#include <netdb.h> +#include <string.h> +#include <stdlib.h> +#include <syslog.h> +#include <getopt.h> +#include <netdb.h> +#include <errno.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <xtables.h> + +#include <linux/netfilter/xt_policy.h> + +/* + * HACK: global pointer to current matchinfo for making + * final checks and adjustments in final_check. + */ +static struct xt_policy_info *policy_info; + +static void policy_help(void) +{ + printf( +"policy match options:\n" +" --dir in|out match policy applied during decapsulation/\n" +" policy to be applied during encapsulation\n" +" --pol none|ipsec match policy\n" +" --strict match entire policy instead of single element\n" +" at any position\n" +"[!] --reqid reqid match reqid\n" +"[!] --spi spi match SPI\n" +"[!] --proto proto match protocol (ah/esp/ipcomp)\n" +"[!] --mode mode match mode (transport/tunnel)\n" +"[!] --tunnel-src addr/mask match tunnel source\n" +"[!] --tunnel-dst addr/mask match tunnel destination\n" +" --next begin next element in policy\n"); +} + +static const struct option policy_opts[] = +{ + { + .name = "dir", + .has_arg = 1, + .val = '1', + }, + { + .name = "pol", + .has_arg = 1, + .val = '2', + }, + { + .name = "strict", + .val = '3' + }, + { + .name = "reqid", + .has_arg = 1, + .val = '4', + }, + { + .name = "spi", + .has_arg = 1, + .val = '5' + }, + { + .name = "tunnel-src", + .has_arg = 1, + .val = '6' + }, + { + .name = "tunnel-dst", + .has_arg = 1, + .val = '7' + }, + { + .name = "proto", + .has_arg = 1, + .val = '8' + }, + { + .name = "mode", + .has_arg = 1, + .val = '9' + }, + { + .name = "next", + .val = 'a' + }, + { .name = NULL } +}; + +static int parse_direction(char *s) +{ + if (strcmp(s, "in") == 0) + return XT_POLICY_MATCH_IN; + if (strcmp(s, "out") == 0) + return XT_POLICY_MATCH_OUT; + xtables_error(PARAMETER_PROBLEM, "policy_match: invalid dir \"%s\"", s); +} + +static int parse_policy(char *s) +{ + if (strcmp(s, "none") == 0) + return XT_POLICY_MATCH_NONE; + if (strcmp(s, "ipsec") == 0) + return 0; + xtables_error(PARAMETER_PROBLEM, "policy match: invalid policy \"%s\"", s); +} + +static int parse_mode(char *s) +{ + if (strcmp(s, "transport") == 0) + return XT_POLICY_MODE_TRANSPORT; + if (strcmp(s, "tunnel") == 0) + return XT_POLICY_MODE_TUNNEL; + xtables_error(PARAMETER_PROBLEM, "policy match: invalid mode \"%s\"", s); +} + +static int policy_parse(int c, char **argv, int invert, unsigned int *flags, + struct xt_policy_info *info, uint8_t family) +{ + struct xt_policy_elem *e = &info->pol[info->len]; + struct in_addr *addr = NULL, mask; + struct in6_addr *addr6 = NULL, mask6; + unsigned int naddr = 0, num; + int mode; + + xtables_check_inverse(optarg, &invert, &optind, 0, argv); + + switch (c) { + case '1': + if (info->flags & (XT_POLICY_MATCH_IN | XT_POLICY_MATCH_OUT)) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --dir option"); + if (invert) + xtables_error(PARAMETER_PROBLEM, + "policy match: can't invert --dir option"); + + info->flags |= parse_direction(optarg); + break; + case '2': + if (invert) + xtables_error(PARAMETER_PROBLEM, + "policy match: can't invert --policy option"); + + info->flags |= parse_policy(optarg); + break; + case '3': + if (info->flags & XT_POLICY_MATCH_STRICT) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --strict option"); + + if (invert) + xtables_error(PARAMETER_PROBLEM, + "policy match: can't invert --strict option"); + + info->flags |= XT_POLICY_MATCH_STRICT; + break; + case '4': + if (e->match.reqid) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --reqid option"); + + e->match.reqid = 1; + e->invert.reqid = invert; + if (!xtables_strtoui(optarg, NULL, &num, 0, UINT32_MAX)) + xtables_param_act(XTF_BAD_VALUE, "policy", "--spi", optarg); + e->reqid = num; + break; + case '5': + if (e->match.spi) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --spi option"); + + e->match.spi = 1; + e->invert.spi = invert; + if (!xtables_strtoui(optarg, NULL, &num, 0, UINT32_MAX)) + xtables_param_act(XTF_BAD_VALUE, "policy", "--spi", optarg); + e->spi = num; + break; + case '6': + if (e->match.saddr) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --tunnel-src option"); + + if (family == NFPROTO_IPV6) + xtables_ip6parse_any(optarg, &addr6, &mask6, &naddr); + else + xtables_ipparse_any(optarg, &addr, &mask, &naddr); + if (naddr > 1) + xtables_error(PARAMETER_PROBLEM, + "policy match: name resolves to multiple IPs"); + + e->match.saddr = 1; + e->invert.saddr = invert; + if (family == NFPROTO_IPV6) { + memcpy(&e->saddr.a6, addr6, sizeof(*addr6)); + memcpy(&e->smask.a6, &mask6, sizeof(mask6)); + } else { + e->saddr.a4 = addr[0]; + e->smask.a4 = mask; + } + break; + case '7': + if (e->match.daddr) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --tunnel-dst option"); + + if (family == NFPROTO_IPV6) + xtables_ip6parse_any(optarg, &addr6, &mask6, &naddr); + else + xtables_ipparse_any(optarg, &addr, &mask, &naddr); + if (naddr > 1) + xtables_error(PARAMETER_PROBLEM, + "policy match: name resolves to multiple IPs"); + + e->match.daddr = 1; + e->invert.daddr = invert; + if (family == NFPROTO_IPV6) { + memcpy(&e->daddr.a6, addr6, sizeof(*addr6)); + memcpy(&e->dmask.a6, &mask6, sizeof(mask6)); + } else { + e->daddr.a4 = addr[0]; + e->dmask.a4 = mask; + } + break; + case '8': + if (e->match.proto) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --proto option"); + + e->proto = xtables_parse_protocol(optarg); + if (e->proto != IPPROTO_AH && e->proto != IPPROTO_ESP && + e->proto != IPPROTO_COMP) + xtables_error(PARAMETER_PROBLEM, + "policy match: protocol must ah/esp/ipcomp"); + e->match.proto = 1; + e->invert.proto = invert; + break; + case '9': + if (e->match.mode) + xtables_error(PARAMETER_PROBLEM, + "policy match: double --mode option"); + + mode = parse_mode(optarg); + e->match.mode = 1; + e->invert.mode = invert; + e->mode = mode; + break; + case 'a': + if (invert) + xtables_error(PARAMETER_PROBLEM, + "policy match: can't invert --next option"); + + if (++info->len == XT_POLICY_MAX_ELEM) + xtables_error(PARAMETER_PROBLEM, + "policy match: maximum policy depth reached"); + break; + default: + return 0; + } + + policy_info = info; + return 1; +} + +static int policy4_parse(int c, char **argv, int invert, unsigned int *flags, + const void *entry, struct xt_entry_match **match) +{ + return policy_parse(c, argv, invert, flags, (void *)(*match)->data, + NFPROTO_IPV4); +} + +static int policy6_parse(int c, char **argv, int invert, unsigned int *flags, + const void *entry, struct xt_entry_match **match) +{ + return policy_parse(c, argv, invert, flags, (void *)(*match)->data, + NFPROTO_IPV6); +} + +static void policy_check(unsigned int flags) +{ + struct xt_policy_info *info = policy_info; + struct xt_policy_elem *e; + int i; + + if (info == NULL) + xtables_error(PARAMETER_PROBLEM, + "policy match: no parameters given"); + + if (!(info->flags & (XT_POLICY_MATCH_IN | XT_POLICY_MATCH_OUT))) + xtables_error(PARAMETER_PROBLEM, + "policy match: neither --dir in nor --dir out specified"); + + if (info->flags & XT_POLICY_MATCH_NONE) { + if (info->flags & XT_POLICY_MATCH_STRICT) + xtables_error(PARAMETER_PROBLEM, + "policy match: policy none but --strict given"); + + if (info->len != 0) + xtables_error(PARAMETER_PROBLEM, + "policy match: policy none but policy given"); + } else + info->len++; /* increase len by 1, no --next after last element */ + + if (!(info->flags & XT_POLICY_MATCH_STRICT) && info->len > 1) + xtables_error(PARAMETER_PROBLEM, + "policy match: multiple elements but no --strict"); + + for (i = 0; i < info->len; i++) { + e = &info->pol[i]; + + if (info->flags & XT_POLICY_MATCH_STRICT && + !(e->match.reqid || e->match.spi || e->match.saddr || + e->match.daddr || e->match.proto || e->match.mode)) + xtables_error(PARAMETER_PROBLEM, + "policy match: empty policy element"); + + if ((e->match.saddr || e->match.daddr) + && ((e->mode == XT_POLICY_MODE_TUNNEL && e->invert.mode) || + (e->mode == XT_POLICY_MODE_TRANSPORT && !e->invert.mode))) + xtables_error(PARAMETER_PROBLEM, + "policy match: --tunnel-src/--tunnel-dst " + "is only valid in tunnel mode"); + } +} + +static void print_mode(const char *prefix, u_int8_t mode, int numeric) +{ + printf("%smode ", prefix); + + switch (mode) { + case XT_POLICY_MODE_TRANSPORT: + printf("transport "); + break; + case XT_POLICY_MODE_TUNNEL: + printf("tunnel "); + break; + default: + printf("??? "); + break; + } +} + +static void print_proto(const char *prefix, u_int8_t proto, int numeric) +{ + struct protoent *p = NULL; + + printf("%sproto ", prefix); + if (!numeric) + p = getprotobynumber(proto); + if (p != NULL) + printf("%s ", p->p_name); + else + printf("%u ", proto); +} + +#define PRINT_INVERT(x) \ +do { \ + if (x) \ + printf("! "); \ +} while(0) + +static void print_entry(const char *prefix, const struct xt_policy_elem *e, + bool numeric, uint8_t family) +{ + if (e->match.reqid) { + PRINT_INVERT(e->invert.reqid); + printf("%sreqid %u ", prefix, e->reqid); + } + if (e->match.spi) { + PRINT_INVERT(e->invert.spi); + printf("%sspi 0x%x ", prefix, e->spi); + } + if (e->match.proto) { + PRINT_INVERT(e->invert.proto); + print_proto(prefix, e->proto, numeric); + } + if (e->match.mode) { + PRINT_INVERT(e->invert.mode); + print_mode(prefix, e->mode, numeric); + } + if (e->match.daddr) { + PRINT_INVERT(e->invert.daddr); + if (family == NFPROTO_IPV6) + printf("%stunnel-dst %s%s ", prefix, + xtables_ip6addr_to_numeric(&e->daddr.a6), + xtables_ip6mask_to_numeric(&e->dmask.a6)); + else + printf("%stunnel-dst %s%s ", prefix, + xtables_ipaddr_to_numeric(&e->daddr.a4), + xtables_ipmask_to_numeric(&e->dmask.a4)); + } + if (e->match.saddr) { + PRINT_INVERT(e->invert.saddr); + if (family == NFPROTO_IPV6) + printf("%stunnel-src %s%s ", prefix, + xtables_ip6addr_to_numeric(&e->saddr.a6), + xtables_ip6mask_to_numeric(&e->smask.a6)); + else + printf("%stunnel-src %s%s ", prefix, + xtables_ipaddr_to_numeric(&e->saddr.a4), + xtables_ipmask_to_numeric(&e->smask.a4)); + } +} + +static void print_flags(char *prefix, const struct xt_policy_info *info) +{ + if (info->flags & XT_POLICY_MATCH_IN) + printf("%sdir in ", prefix); + else + printf("%sdir out ", prefix); + + if (info->flags & XT_POLICY_MATCH_NONE) + printf("%spol none ", prefix); + else + printf("%spol ipsec ", prefix); + + if (info->flags & XT_POLICY_MATCH_STRICT) + printf("%sstrict ", prefix); +} + +static void policy4_print(const void *ip, const struct xt_entry_match *match, + int numeric) +{ + const struct xt_policy_info *info = (void *)match->data; + unsigned int i; + + printf("policy match "); + print_flags("", info); + for (i = 0; i < info->len; i++) { + if (info->len > 1) + printf("[%u] ", i); + print_entry("", &info->pol[i], numeric, NFPROTO_IPV4); + } +} + +static void policy6_print(const void *ip, const struct xt_entry_match *match, + int numeric) +{ + const struct xt_policy_info *info = (void *)match->data; + unsigned int i; + + printf("policy match "); + print_flags("", info); + for (i = 0; i < info->len; i++) { + if (info->len > 1) + printf("[%u] ", i); + print_entry("", &info->pol[i], numeric, NFPROTO_IPV6); + } +} + +static void policy4_save(const void *ip, const struct xt_entry_match *match) +{ + const struct xt_policy_info *info = (void *)match->data; + unsigned int i; + + print_flags("--", info); + for (i = 0; i < info->len; i++) { + print_entry("--", &info->pol[i], false, NFPROTO_IPV4); + if (i + 1 < info->len) + printf("--next "); + } +} + +static void policy6_save(const void *ip, const struct xt_entry_match *match) +{ + const struct xt_policy_info *info = (void *)match->data; + unsigned int i; + + print_flags("--", info); + for (i = 0; i < info->len; i++) { + print_entry("--", &info->pol[i], false, NFPROTO_IPV6); + if (i + 1 < info->len) + printf("--next "); + } +} + +static struct xtables_match policy_mt_reg[] = { + { + .name = "policy", + .version = XTABLES_VERSION, + .family = NFPROTO_IPV4, + .size = XT_ALIGN(sizeof(struct xt_policy_info)), + .userspacesize = XT_ALIGN(sizeof(struct xt_policy_info)), + .help = policy_help, + .parse = policy4_parse, + .final_check = policy_check, + .print = policy4_print, + .save = policy4_save, + .extra_opts = policy_opts, + }, + { + .name = "policy", + .version = XTABLES_VERSION, + .family = NFPROTO_IPV6, + .size = XT_ALIGN(sizeof(struct xt_policy_info)), + .userspacesize = XT_ALIGN(sizeof(struct xt_policy_info)), + .help = policy_help, + .parse = policy6_parse, + .final_check = policy_check, + .print = policy6_print, + .save = policy6_save, + .extra_opts = policy_opts, + }, +}; + +void _init(void) +{ + xtables_register_matches(policy_mt_reg, ARRAY_SIZE(policy_mt_reg)); +} |