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/* Shared library add-on to iptables to add OWNER matching support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <pwd.h>
#include <grp.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ipt_owner.h>
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"OWNER match v%s options:\n"
"[!] --uid-owner userid Match local uid\n"
"[!] --gid-owner groupid Match local gid\n"
"[!] --pid-owner processid Match local pid\n"
"[!] --sid-owner sessionid Match local sid\n"
"\n",
NETFILTER_VERSION);
}
static struct option opts[] = {
{ "uid-owner", 1, 0, '1' },
{ "gid-owner", 1, 0, '2' },
{ "pid-owner", 1, 0, '3' },
{ "sid-owner", 1, 0, '4' },
{0}
};
/* Initialize the match. */
static void
init(struct ipt_entry_match *m, unsigned int *nfcache)
{
/* Can't cache this. */
*nfcache |= NFC_UNKNOWN;
}
/* Function which parses command options; returns true if it
ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
unsigned int *nfcache,
struct ipt_entry_match **match)
{
struct ipt_owner_info *ownerinfo = (struct ipt_owner_info *)(*match)->data;
switch (c) {
char *end;
struct passwd *pwd;
struct group *grp;
case '1':
if (check_inverse(optarg, &invert))
optind++;
if ((pwd = getpwnam(optarg)))
ownerinfo->uid = pwd->pw_uid;
else {
ownerinfo->uid = strtoul(optarg, &end, 0);
if (*end != '\0' || end == optarg)
exit_error(PARAMETER_PROBLEM, "Bad OWNER UID value `%s'", optarg);
}
if (invert)
ownerinfo->invert |= IPT_OWNER_UID;
ownerinfo->match |= IPT_OWNER_UID;
*flags = 1;
break;
case '2':
if (check_inverse(optarg, &invert))
optind++;
if ((grp = getgrnam(optarg)))
ownerinfo->gid = grp->gr_gid;
else {
ownerinfo->gid = strtoul(optarg, &end, 0);
if (*end != '\0' || end == optarg)
exit_error(PARAMETER_PROBLEM, "Bad OWNER GID value `%s'", optarg);
}
if (invert)
ownerinfo->invert |= IPT_OWNER_GID;
ownerinfo->match |= IPT_OWNER_GID;
*flags = 1;
break;
case '3':
if (check_inverse(optarg, &invert))
optind++;
ownerinfo->pid = strtoul(optarg, &end, 0);
if (*end != '\0' || end == optarg)
exit_error(PARAMETER_PROBLEM, "Bad OWNER PID value `%s'", optarg);
if (invert)
ownerinfo->invert |= IPT_OWNER_PID;
ownerinfo->match |= IPT_OWNER_PID;
*flags = 1;
break;
case '4':
if (check_inverse(optarg, &invert))
optind++;
ownerinfo->sid = strtoul(optarg, &end, 0);
if (*end != '\0' || end == optarg)
exit_error(PARAMETER_PROBLEM, "Bad OWNER SID value `%s'", optarg);
if (invert)
ownerinfo->invert |= IPT_OWNER_SID;
ownerinfo->match |= IPT_OWNER_SID;
*flags = 1;
break;
default:
return 0;
}
return 1;
}
static void
print_item(struct ipt_owner_info *info, u_int8_t flag, int numeric, char *label)
{
if(info->match & flag) {
printf(label);
if (info->invert & flag)
fputc('!', stdout);
switch(info->match & flag) {
case IPT_OWNER_UID:
if(!numeric) {
struct passwd *pwd = getpwuid(info->uid);
if(pwd && pwd->pw_name) {
printf("%s ", pwd->pw_name);
break;
}
/* FALLTHROUGH */
}
printf("%u ", info->uid);
break;
case IPT_OWNER_GID:
if(!numeric) {
struct group *grp = getgrgid(info->gid);
if(grp && grp->gr_name) {
printf("%s ", grp->gr_name);
break;
}
/* FALLTHROUGH */
}
printf("%u ", info->gid);
break;
case IPT_OWNER_PID:
printf("%u ", info->pid);
break;
case IPT_OWNER_SID:
printf("%u ", info->sid);
break;
default:
break;
}
}
}
/* Final check; must have specified --own. */
static void
final_check(unsigned int flags)
{
if (!flags)
exit_error(PARAMETER_PROBLEM,
"OWNER match: You must specify one or more options");
}
/* Prints out the matchinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_match *match,
int numeric)
{
struct ipt_owner_info *info = (struct ipt_owner_info *)match->data;
print_item(info, IPT_OWNER_UID, numeric, "OWNER UID match ");
print_item(info, IPT_OWNER_GID, numeric, "OWNER GID match ");
print_item(info, IPT_OWNER_PID, numeric, "OWNER PID match ");
print_item(info, IPT_OWNER_SID, numeric, "OWNER SID match ");
}
/* Saves the union ipt_matchinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
struct ipt_owner_info *info = (struct ipt_owner_info *)match->data;
print_item(info, IPT_OWNER_UID, 0, "--uid-owner ");
print_item(info, IPT_OWNER_GID, 0, "--gid-owner ");
print_item(info, IPT_OWNER_PID, 0, "--pid-owner ");
print_item(info, IPT_OWNER_SID, 0, "--sid-owner ");
}
struct iptables_match owner
= { NULL,
"owner",
NETFILTER_VERSION,
IPT_ALIGN(sizeof(struct ipt_owner_info)),
IPT_ALIGN(sizeof(struct ipt_owner_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_match(&owner);
}
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