int execute_cmd(char *cmd, int in)
{
char *p = cmd;
char *start_cmd = cmd;
int pipefd[2];
while (*p) {
switch (*p) {
case '|':
*p++ = 0;
//创建一个管道
pipe(pipefd);
//下面的语句执行后，程序分叉，第一叉在当前捕获的命令，第二
//叉在后面继续解析命令
//将写管道传给当前捕获的命令用于重定向其stdout
if (fork_and_exec(start_cmd, in, pipefd[1]) > 0) {
//将读管道传给将要被捕获的命令用于重定向其stdin
goto call_forward_pipe_chain;
}
break;
default:
p++;
}
}
fork_and_exec(start_cmd, in, -1);
fflush(stdout);
return 0;
call_forward_pipe_chain:
execute_cmd(p, pipefd[0]);
fflush(stdout);
return 0;
}
static void
do_help (saver_screen_info *ssi)
{
saver_info *si = ssi->global;
saver_preferences *p = &si->prefs;
char *help_command = 0;
if (!p->load_url_command || !*p->load_url_command)
{
fprintf (stderr, "%s: no URL command has been specified.\n", blurb());
return;
}
if (!p->help_url || !*p->help_url)
{
fprintf (stderr, "%s: no Help URL has been specified.\n", blurb());
return;
}
help_command = (char *) malloc (strlen (p->load_url_command) +
(strlen (p->help_url) * 4) + 10);
sprintf (help_command, p->load_url_command,
p->help_url, p->help_url, p->help_url, p->help_url);
fork_and_exec (ssi, help_command);
free (help_command);
}
void VMError::show_message_box(char *buf, int buflen) {
bool yes;
do {
error_string(buf, buflen);
int len = (int)strlen(buf);
char *p = &buf[len];
jio_snprintf(p, buflen - len,
"\n\n"
"Do you want to debug the problem?\n\n"
"To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " INTX_FORMAT "\n"
"Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
"Otherwise, press RETURN to abort...",
os::current_process_id(), os::current_process_id(),
os::current_thread_id());
yes = os::message_box("Unexpected Error", buf);
if (yes) {
// yes, user asked VM to launch debugger
jio_snprintf(buf, buflen, "gdb /proc/%d/exe %d",
os::current_process_id(), os::current_process_id());
fork_and_exec(buf);
}
} while (yes);
}
static void
do_prefs (saver_screen_info *ssi)
{
saver_info *si = ssi->global;
saver_preferences *p = &si->prefs;
const char *cmd = p->prefs_command;
if (command && *command)
fork_and_exec (ssi, cmd);
else
fprintf (stderr, "%s: no preferences command has been specified.\n",
blurb());
}
int do_pipes(t_dlist *list, char ***env)
{
t_pipes var;
init_function_pipe(&var);
while (var.i < list->taille)
{
if (list->begin->s != NULL && list->begin->s[0] == '<')
{
list->begin = list->begin->next;
if ((var.fd_in = redirection_left(list, &var.i, &var.j)) == -1)
return (0);
}
if (do_next_command(list->begin, list->end, &var) == -1)
return (0);
if (var.j == 0)
fork_and_exec(list->begin, env, var.fd_in, var.fd_out);
else
var.j = fork_and_exec(list->begin->prev, env, var.fd_in, var.fd_out);
close_function_pipe(&var);
list->begin = list->begin->next;
}
return (0);
}
int main()
{
char cmdline[1024];
char *args[64];
char * pathArgs[64];
char fullcmd [100];
int i;
printf("%s","This is a Simple Shell \n");
while(1)
{
i = 0;
print_prompt();
// printf("%s", "test 1");
read_command(cmdline);
// printf("%s", "test 2");
// printf("After read_command %s \n", buf);
parse_command(cmdline, args);
// printf("%s", "test 3");
// printf("After parse_command %s \n", buf);
// printf("After parse_comamnd %s \n", args);
// printf("More curiosity \n");
file_find(pathArgs, cmdline, fullcmd);
// while (pathArgs[i] != NULL){
// strcat(pathArgs[i], "/");
// //printf("args [i] is: %s/ls\n", pathArgs[i]);
// i++;
// }
// printf("After file_find %s \n", args);
// printf("%s", "test 4");
// printf("%s", *args);
fork_and_exec(args, fullcmd);
//printf("After fork %s", buf);
//printf("%s", "test 5 \n");
return 0;
}
}
int
main (int argc, char *const *argv)
{
char *sbin_iptables;
char *bin_vpn;
char *bin_exit;
char *bin_dns;
char *srv_dns;
struct stat s;
gid_t my_gid;
char *const iptables_args[] =
{
"iptables", "-t", "mangle", "-L", "-v", NULL
};
if (0 == access ("/sbin/iptables", X_OK))
sbin_iptables = "/sbin/iptables";
else if (0 == access ("/usr/sbin/iptables", X_OK))
sbin_iptables = "/usr/sbin/iptables";
else
{
fprintf (stderr,
"Executable iptables not found in approved directories: %s, skipping\n",
strerror (errno));
return 0;
}
if (0 != fork_and_exec (sbin_iptables, iptables_args))
{
fprintf (stderr,
"Failed to run `iptables -t mangle -L -v'. Skipping test.\n");
return 0;
}
if (0 != ACCESS ("/dev/net/tun", R_OK))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
"access",
"/dev/net/tun");
fprintf (stderr,
"WARNING: System unable to run test, skipping.\n");
return 0;
}
bin_vpn = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-vpn");
bin_exit = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-exit");
bin_dns = GNUNET_OS_get_libexec_binary_path ("gnunet-helper-dns");
srv_dns = GNUNET_OS_get_libexec_binary_path ("gnunet-service-dns");
if ( (0 != geteuid ()) &&
( (GNUNET_YES !=
GNUNET_OS_check_helper_binary (bin_vpn, GNUNET_YES, "-d gnunet-vpn - - 169.1.3.3.7 255.255.255.0")) || //ipv4 only please!
(GNUNET_YES !=
GNUNET_OS_check_helper_binary (bin_exit, GNUNET_YES, "-d gnunet-vpn - - - 169.1.3.3.7 255.255.255.0")) || //no nat, ipv4 only
(GNUNET_YES !=
GNUNET_OS_check_helper_binary (bin_dns, GNUNET_YES, NULL))) ) // TODO: once we have a windows-testcase, add test parameters here
{
fprintf (stderr,
"WARNING: gnunet-helper-{exit,vpn,dns} binaries in $PATH are not SUID, refusing to run test (as it would have to fail).\n");
fprintf (stderr,
"Change $PATH ('.' in $PATH before $GNUNET_PREFIX/bin is problematic) or permissions (run 'make install' as root) to fix this!\n");
GNUNET_free (bin_vpn);
GNUNET_free (bin_exit);
GNUNET_free (bin_dns);
GNUNET_free (srv_dns);
return 0;
}
GNUNET_free (bin_vpn);
GNUNET_free (bin_exit);
my_gid = getgid ();
if ( (0 != stat (bin_dns, &s)) ||
(my_gid == s.st_gid) ||
( (0 == (S_ISUID & s.st_mode)) && (0 != getuid()) ) )
{
fprintf (stderr,
"WARNING: %s has wrong permissions (%d, %d, %d), refusing to run test (as it would have to fail).\n",
bin_dns,
(0 != stat (bin_dns, &s)),
(my_gid == s.st_gid),
(0 == (S_ISUID & s.st_mode)) || (0 != getuid()) );
GNUNET_free (bin_dns);
GNUNET_free (srv_dns);
return 0;
}
if ( (0 != stat (srv_dns, &s)) ||
(my_gid == s.st_gid) ||
(0 == (S_ISGID & s.st_mode)) )
{
fprintf (stderr,
"WARNING: %s has wrong permissions (%d, %d, %d), refusing to run test (as it would have to fail).\n",
srv_dns,
(0 != stat (bin_dns, &s)),
(my_gid == s.st_gid),
(0 == (S_ISGID & s.st_mode)) );
GNUNET_free (bin_dns);
GNUNET_free (srv_dns);
return 0;
}
GNUNET_free (bin_dns);
GNUNET_free (srv_dns);
dest_ip = "169.254.86.1";
dest_af = AF_INET;
src_af = AF_INET;
if (GNUNET_OK == GNUNET_NETWORK_test_pf (PF_INET6))
use_v6 = GNUNET_YES;
else
use_v6 = GNUNET_NO;
if ( (GNUNET_OK != GNUNET_NETWORK_test_pf (src_af)) ||
(GNUNET_OK != GNUNET_NETWORK_test_pf (dest_af)) )
{
fprintf (stderr,
"Required address families not supported by this system, skipping test.\n");
return 0;
}
if (0 != curl_global_init (CURL_GLOBAL_WIN32))
{
fprintf (stderr, "failed to initialize curl\n");
return 2;
}
if (0 != GNUNET_TESTING_peer_run ("test-gnunet-vpn",
"test_gns_vpn.conf",
&run, NULL))
return 1;
GNUNET_DISK_directory_remove ("/tmp/gnunet-test-vpn");
return global_ret;
}
static void
run (void *cls,
const struct GNUNET_CONFIGURATION_Handle *cfg,
struct GNUNET_TESTING_Peer *peer)
{
enum MHD_FLAG flags;
char *bin;
char *bin_identity;
char *bin_gns;
char *config;
if (GNUNET_OK !=
GNUNET_CONFIGURATION_get_value_string (cfg,
"arm",
"CONFIG",
&config))
{
fprintf (stderr,
"Failed to locate configuration file. Skipping test.\n");
GNUNET_SCHEDULER_shutdown ();
return;
}
char *const identity_args[] =
{
"gnunet-identity",
"-C", "master-zone",
"-c", config,
NULL
};
char *const identity2_args[] =
{
"gnunet-identity",
"-e", "master-zone",
"-s", "gns-master",
"-c", config,
NULL
};
char *const identity3_args[] =
{
"gnunet-identity",
"-e", "master-zone",
"-s", "gns-intercept",
"-c", config,
NULL
};
char *const gns_args[] =
{
"gnunet-gns",
"-u", "www.gns",
"-c", config,
NULL
};
GNUNET_TESTING_peer_get_identity (peer, &id);
GNUNET_SCHEDULER_add_delayed (TIMEOUT,
&do_shutdown,
NULL);
bin = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_BINDIR);
GNUNET_asprintf (&bin_identity,
"%s/%s",
bin,
"gnunet-identity");
if (0 != fork_and_exec (bin_identity, identity_args))
{
fprintf (stderr,
"Failed to run `gnunet-identity -C. Skipping test.\n");
GNUNET_SCHEDULER_shutdown ();
GNUNET_free (bin_identity);
GNUNET_free (config);
GNUNET_free (bin);
return;
}
if (0 != fork_and_exec (bin_identity, identity2_args))
{
fprintf (stderr,
"Failed to run `gnunet-identity -e. Skipping test.\n");
GNUNET_SCHEDULER_shutdown ();
GNUNET_free (bin_identity);
GNUNET_free (config);
GNUNET_free (bin);
return;
}
if (0 != fork_and_exec (bin_identity, identity3_args))
{
fprintf (stderr,
"Failed to run `gnunet-identity -e. Skipping test.\n");
GNUNET_SCHEDULER_shutdown ();
GNUNET_free (bin_identity);
GNUNET_free (config);
GNUNET_free (bin);
return;
}
GNUNET_free (bin_identity);
/* do lookup just to launch GNS service */
GNUNET_asprintf (&bin_gns,
"%s/%s",
bin,
"gnunet-gns");
if (0 != fork_and_exec (bin_gns, gns_args))
{
fprintf (stderr,
"Failed to run `gnunet-gns -u. Skipping test.\n");
GNUNET_SCHEDULER_shutdown ();
GNUNET_free (bin_gns);
GNUNET_free (config);
GNUNET_free (bin);
return;
}
GNUNET_free (bin_gns);
GNUNET_free (config);
GNUNET_free (bin);
namestore = GNUNET_NAMESTORE_connect (cfg);
GNUNET_assert (NULL != namestore);
flags = MHD_USE_DEBUG;
if (GNUNET_YES == use_v6)
flags |= MHD_USE_DUAL_STACK;
mhd = MHD_start_daemon (flags,
PORT,
NULL, NULL,
&mhd_ahc, NULL,
MHD_OPTION_END);
GNUNET_assert (NULL != mhd);
mhd_main ();
identity = GNUNET_IDENTITY_connect (cfg,
&identity_cb,
NULL);
}
/**
* Main function of "gnunet-helper-dns", which opens a VPN tunnel interface,
* redirects all outgoing DNS traffic (except from the specified port) to that
* interface and then passes traffic from and to the interface via stdin/stdout.
*
* Once stdin/stdout close or have other errors, the tunnel is closed and the
* DNS traffic redirection is stopped.
*
* @param argc number of arguments
* @param argv 0: binary name (should be "gnunet-helper-vpn")
* 1: tunnel interface name (typically "gnunet-dns")
* 2: IPv6 address for the tunnel ("FE80::1")
* 3: IPv6 netmask length in bits ("64")
* 4: IPv4 address for the tunnel ("1.2.3.4")
* 5: IPv4 netmask ("255.255.0.0")
* 6: skip sysctl, routing and iptables setup ("0")
* @return 0 on success, otherwise code indicating type of error:
* 1 wrong number of arguments
* 2 invalid arguments (i.e. port number / prefix length wrong)
* 3 iptables not executable
* 4 ip not executable
* 5 failed to initialize tunnel interface
* 6 failed to initialize control pipe
* 8 failed to change routing table, cleanup successful
* 9-23 failed to change routing table and failed to undo some changes to routing table
* 24 failed to drop privs
* 25-39 failed to drop privs and then failed to undo some changes to routing table
* 40 failed to regain privs
* 41-55 failed to regain prisv and then failed to undo some changes to routing table
* 254 insufficient priviledges
* 255 failed to handle kill signal properly
*/
int
main (int argc, char *const*argv)
{
int r;
char dev[IFNAMSIZ];
char mygid[32];
int fd_tun;
uid_t uid;
int nortsetup = 0;
if (7 != argc)
{
fprintf (stderr, "Fatal: must supply 6 arguments!\n");
return 1;
}
/* assert privs so we can modify the firewall rules! */
uid = getuid ();
#ifdef HAVE_SETRESUID
if (0 != setresuid (uid, 0, 0))
{
fprintf (stderr, "Failed to setresuid to root: %s\n", strerror (errno));
return 254;
}
#else
if (0 != seteuid (0))
{
fprintf (stderr, "Failed to seteuid back to root: %s\n", strerror (errno));
return 254;
}
#endif
if (0 == strncmp (argv[6], "1", 2))
nortsetup = 1;
if (0 == nortsetup)
{
/* verify that the binaries we care about are executable */
if (0 == access ("/sbin/iptables", X_OK))
sbin_iptables = "/sbin/iptables";
else if (0 == access ("/usr/sbin/iptables", X_OK))
sbin_iptables = "/usr/sbin/iptables";
else
{
fprintf (stderr,
"Fatal: executable iptables not found in approved directories: %s\n",
strerror (errno));
return 3;
}
if (0 == access ("/sbin/ip6tables", X_OK))
sbin_ip6tables = "/sbin/ip6tables";
else if (0 == access ("/usr/sbin/ip6tables", X_OK))
sbin_ip6tables = "/usr/sbin/ip6tables";
else
{
fprintf (stderr,
"Fatal: executable ip6tables not found in approved directories: %s\n",
strerror (errno));
return 3;
}
if (0 == access ("/sbin/ip", X_OK))
sbin_ip = "/sbin/ip";
else if (0 == access ("/usr/sbin/ip", X_OK))
sbin_ip = "/usr/sbin/ip";
else
{
fprintf (stderr,
"Fatal: executable ip not found in approved directories: %s\n",
strerror (errno));
return 4;
}
if (0 == access ("/sbin/sysctl", X_OK))
sbin_sysctl = "/sbin/sysctl";
else if (0 == access ("/usr/sbin/sysctl", X_OK))
sbin_sysctl = "/usr/sbin/sysctl";
else
{
fprintf (stderr,
"Fatal: executable sysctl not found in approved directories: %s\n",
strerror (errno));
return 5;
}
}
/* setup 'mygid' string */
snprintf (mygid, sizeof (mygid), "%d", (int) getegid());
/* do not die on SIGPIPE */
if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
{
fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",
strerror (errno));
return 7;
}
/* setup pipe to shutdown nicely on SIGINT */
if (0 != pipe (cpipe))
{
fprintf (stderr,
"Fatal: could not setup control pipe: %s\n",
strerror (errno));
return 6;
}
if (cpipe[0] >= FD_SETSIZE)
{
fprintf (stderr, "Pipe file descriptor to large: %d", cpipe[0]);
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 6;
}
{
/* make pipe non-blocking, as we theoretically could otherwise block
in the signal handler */
int flags = fcntl (cpipe[1], F_GETFL);
if (-1 == flags)
{
fprintf (stderr, "Failed to read flags for pipe: %s", strerror (errno));
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 6;
}
flags |= O_NONBLOCK;
if (0 != fcntl (cpipe[1], F_SETFL, flags))
{
fprintf (stderr, "Failed to make pipe non-blocking: %s", strerror (errno));
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 6;
}
}
if ( (SIG_ERR == signal (SIGTERM, &signal_handler)) ||
#if (SIGTERM != GNUNET_TERM_SIG)
(SIG_ERR == signal (GNUNET_TERM_SIG, &signal_handler)) ||
#endif
(SIG_ERR == signal (SIGINT, &signal_handler)) ||
(SIG_ERR == signal (SIGHUP, &signal_handler)) )
{
fprintf (stderr,
"Fatal: could not initialize signal handler: %s\n",
strerror (errno));
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 7;
}
/* get interface name */
strncpy (dev, argv[1], IFNAMSIZ);
dev[IFNAMSIZ - 1] = '\0';
/* Disable rp filtering */
if (0 == nortsetup)
{
char *const sysctl_args[] = {"sysctl", "-w",
"net.ipv4.conf.all.rp_filter=0", NULL};
char *const sysctl_args2[] = {"sysctl", "-w",
"net.ipv4.conf.default.rp_filter=0", NULL};
if ((0 != fork_and_exec (sbin_sysctl, sysctl_args)) ||
(0 != fork_and_exec (sbin_sysctl, sysctl_args2)))
{
fprintf (stderr,
"Failed to disable rp filtering.\n");
return 5;
}
}
/* now open virtual interface (first part that requires root) */
if (-1 == (fd_tun = init_tun (dev)))
{
fprintf (stderr, "Fatal: could not initialize tun-interface\n");
(void) signal (SIGTERM, SIG_IGN);
#if (SIGTERM != GNUNET_TERM_SIG)
(void) signal (GNUNET_TERM_SIG, SIG_IGN);
#endif
(void) signal (SIGINT, SIG_IGN);
(void) signal (SIGHUP, SIG_IGN);
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 5;
}
/* now set interface addresses */
{
const char *address = argv[2];
long prefix_len = atol (argv[3]);
if ((prefix_len < 1) || (prefix_len > 127))
{
fprintf (stderr, "Fatal: prefix_len out of range\n");
(void) signal (SIGTERM, SIG_IGN);
#if (SIGTERM != GNUNET_TERM_SIG)
(void) signal (GNUNET_TERM_SIG, SIG_IGN);
#endif
(void) signal (SIGINT, SIG_IGN);
(void) signal (SIGHUP, SIG_IGN);
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return 2;
}
set_address6 (dev, address, prefix_len);
}
{
const char *address = argv[4];
const char *mask = argv[5];
set_address4 (dev, address, mask);
}
/* update routing tables -- next part why we need SUID! */
/* Forward everything from our EGID (which should only be held
by the 'gnunet-service-dns') and with destination
to port 53 on UDP, without hijacking */
if (0 == nortsetup)
{
r = 8; /* failed to fully setup routing table */
{
char *const mangle_args[] =
{
"iptables", "-m", "owner", "-t", "mangle", "-I", "OUTPUT", "1", "-p",
"udp", "--gid-owner", mygid, "--dport", DNS_PORT, "-j",
"ACCEPT", NULL
};
if (0 != fork_and_exec (sbin_iptables, mangle_args))
goto cleanup_rest;
}
{
char *const mangle_args[] =
{
"ip6tables", "-m", "owner", "-t", "mangle", "-I", "OUTPUT", "1", "-p",
"udp", "--gid-owner", mygid, "--dport", DNS_PORT, "-j",
"ACCEPT", NULL
};
if (0 != fork_and_exec (sbin_ip6tables, mangle_args))
goto cleanup_mangle_1b;
}
/* Mark all of the other DNS traffic using our mark DNS_MARK,
unless it is on a link-local IPv6 address, which we cannot support. */
{
char *const mark_args[] =
{
"iptables", "-t", "mangle", "-I", "OUTPUT", "2", "-p",
"udp", "--dport", DNS_PORT,
"-j", "MARK", "--set-mark", DNS_MARK,
NULL
};
if (0 != fork_and_exec (sbin_iptables, mark_args))
goto cleanup_mangle_1;
}
{
char *const mark_args[] =
{
"ip6tables", "-t", "mangle", "-I", "OUTPUT", "2", "-p",
"udp", "--dport", DNS_PORT,
"!", "-s", "fe80::/10", /* this line excludes link-local traffic */
"-j", "MARK", "--set-mark", DNS_MARK,
NULL
};
if (0 != fork_and_exec (sbin_ip6tables, mark_args))
goto cleanup_mark_2b;
}
/* Forward all marked DNS traffic to our DNS_TABLE */
{
char *const forward_args[] =
{
"ip", "rule", "add", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, forward_args))
goto cleanup_mark_2;
}
{
char *const forward_args[] =
{
"ip", "-6", "rule", "add", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, forward_args))
goto cleanup_forward_3b;
}
/* Finally, add rule in our forwarding table to pass to our virtual interface */
{
char *const route_args[] =
{
"ip", "route", "add", "default", "dev", dev,
"table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, route_args))
goto cleanup_forward_3;
}
{
char *const route_args[] =
{
"ip", "-6", "route", "add", "default", "dev", dev,
"table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, route_args))
goto cleanup_route_4b;
}
}
/* drop privs *except* for the saved UID; this is not perfect, but better
than doing nothing */
#ifdef HAVE_SETRESUID
if (0 != setresuid (uid, uid, 0))
{
fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
r = 24;
goto cleanup_route_4;
}
#else
/* Note: no 'setuid' here as we must keep our saved UID as root */
if (0 != seteuid (uid))
{
fprintf (stderr, "Failed to seteuid: %s\n", strerror (errno));
r = 24;
goto cleanup_route_4;
}
#endif
r = 0; /* did fully setup routing table (if nothing else happens, we were successful!) */
/* now forward until we hit a problem */
run (fd_tun);
/* now need to regain privs so we can remove the firewall rules we added! */
#ifdef HAVE_SETRESUID
if (0 != setresuid (uid, 0, 0))
{
fprintf (stderr, "Failed to setresuid back to root: %s\n", strerror (errno));
r = 40;
goto cleanup_route_4;
}
#else
if (0 != seteuid (0))
{
fprintf (stderr, "Failed to seteuid back to root: %s\n", strerror (errno));
r = 40;
goto cleanup_route_4;
}
#endif
/* update routing tables again -- this is why we could not fully drop privs */
/* now undo updating of routing tables; normal exit or clean-up-on-error case */
cleanup_route_4:
if (0 == nortsetup)
{
char *const route_clean_args[] =
{
"ip", "-6", "route", "del", "default", "dev", dev,
"table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, route_clean_args))
r += 1;
}
cleanup_route_4b:
if (0 == nortsetup)
{
char *const route_clean_args[] =
{
"ip", "route", "del", "default", "dev", dev,
"table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, route_clean_args))
r += 1;
}
cleanup_forward_3:
if (0 == nortsetup)
{
char *const forward_clean_args[] =
{
"ip", "-6", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, forward_clean_args))
r += 2;
}
cleanup_forward_3b:
if (0 == nortsetup)
{
char *const forward_clean_args[] =
{
"ip", "rule", "del", "fwmark", DNS_MARK, "table", DNS_TABLE, NULL
};
if (0 != fork_and_exec (sbin_ip, forward_clean_args))
r += 2;
}
cleanup_mark_2:
if (0 == nortsetup)
{
char *const mark_clean_args[] =
{
"ip6tables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--dport", DNS_PORT,
"!", "-s", "fe80::/10", /* this line excludes link-local traffic */
"-j", "MARK", "--set-mark", DNS_MARK, NULL
};
if (0 != fork_and_exec (sbin_ip6tables, mark_clean_args))
r += 4;
}
cleanup_mark_2b:
if (0 == nortsetup)
{
char *const mark_clean_args[] =
{
"iptables", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--dport", DNS_PORT, "-j", "MARK", "--set-mark", DNS_MARK, NULL
};
if (0 != fork_and_exec (sbin_iptables, mark_clean_args))
r += 4;
}
cleanup_mangle_1:
if (0 == nortsetup)
{
char *const mangle_clean_args[] =
{
"ip6tables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--gid-owner", mygid, "--dport", DNS_PORT, "-j", "ACCEPT",
NULL
};
if (0 != fork_and_exec (sbin_ip6tables, mangle_clean_args))
r += 8;
}
cleanup_mangle_1b:
if (0 == nortsetup)
{
char *const mangle_clean_args[] =
{
"iptables", "-m", "owner", "-t", "mangle", "-D", "OUTPUT", "-p", "udp",
"--gid-owner", mygid, "--dport", DNS_PORT, "-j", "ACCEPT",
NULL
};
if (0 != fork_and_exec (sbin_iptables, mangle_clean_args))
r += 8;
}
cleanup_rest:
/* close virtual interface */
(void) close (fd_tun);
/* remove signal handler so we can close the pipes */
(void) signal (SIGTERM, SIG_IGN);
#if (SIGTERM != GNUNET_TERM_SIG)
(void) signal (GNUNET_TERM_SIG, SIG_IGN);
#endif
(void) signal (SIGINT, SIG_IGN);
(void) signal (SIGHUP, SIG_IGN);
(void) close (cpipe[0]);
(void) close (cpipe[1]);
return r;
}
/**
* Open VPN tunnel interface.
*
* @param argc must be 6
* @param argv 0: binary name ("gnunet-helper-exit")
* 1: tunnel interface name ("gnunet-exit")
* 2: IPv4 "physical" interface name ("eth0"), or "%" to not do IPv4 NAT
* 3: IPv6 address ("::1"), or "-" to skip IPv6
* 4: IPv6 netmask length in bits ("64") [ignored if #4 is "-"]
* 5: IPv4 address ("1.2.3.4"), or "-" to skip IPv4
* 6: IPv4 netmask ("255.255.0.0") [ignored if #4 is "-"]
*/
int
main (int argc, char **argv)
{
char dev[IFNAMSIZ];
int fd_tun;
int global_ret;
if (7 != argc)
{
fprintf (stderr, "Fatal: must supply 6 arguments!\n");
return 1;
}
if ( (0 == strcmp (argv[3], "-")) &&
(0 == strcmp (argv[5], "-")) )
{
fprintf (stderr, "Fatal: disabling both IPv4 and IPv6 makes no sense.\n");
return 1;
}
if (0 == access ("/sbin/iptables", X_OK))
sbin_iptables = "/sbin/iptables";
else if (0 == access ("/usr/sbin/iptables", X_OK))
sbin_iptables = "/usr/sbin/iptables";
else
{
fprintf (stderr,
"Fatal: executable iptables not found in approved directories: %s\n",
strerror (errno));
return 1;
}
if (0 == access ("/sbin/sysctl", X_OK))
sbin_sysctl = "/sbin/sysctl";
else if (0 == access ("/usr/sbin/sysctl", X_OK))
sbin_sysctl = "/usr/sbin/sysctl";
else
{
fprintf (stderr,
"Fatal: executable sysctl not found in approved directories: %s\n",
strerror (errno));
return 1;
}
strncpy (dev, argv[1], IFNAMSIZ);
dev[IFNAMSIZ - 1] = '\0';
if (-1 == (fd_tun = init_tun (dev)))
{
fprintf (stderr,
"Fatal: could not initialize tun-interface `%s' with IPv6 %s/%s and IPv4 %s/%s\n",
dev,
argv[3],
argv[4],
argv[5],
argv[6]);
return 1;
}
if (0 != strcmp (argv[3], "-"))
{
{
const char *address = argv[3];
long prefix_len = atol (argv[4]);
if ((prefix_len < 1) || (prefix_len > 127))
{
fprintf (stderr, "Fatal: prefix_len out of range\n");
return 1;
}
set_address6 (dev, address, prefix_len);
}
{
char *const sysctl_args[] =
{
"sysctl", "-w", "net.ipv6.conf.all.forwarding=1", NULL
};
if (0 != fork_and_exec (sbin_sysctl,
sysctl_args))
{
fprintf (stderr,
"Failed to enable IPv6 forwarding. Will continue anyway.\n");
}
}
}
if (0 != strcmp (argv[5], "-"))
{
{
const char *address = argv[5];
const char *mask = argv[6];
set_address4 (dev, address, mask);
}
{
char *const sysctl_args[] =
{
"sysctl", "-w", "net.ipv4.ip_forward=1", NULL
};
if (0 != fork_and_exec (sbin_sysctl,
sysctl_args))
{
fprintf (stderr,
"Failed to enable IPv4 forwarding. Will continue anyway.\n");
}
}
if (0 != strcmp (argv[2], "%"))
{
char *const iptables_args[] =
{
"iptables", "-t", "nat", "-A", "POSTROUTING", "-o", argv[2], "-j", "MASQUERADE", NULL
};
if (0 != fork_and_exec (sbin_iptables,
iptables_args))
{
fprintf (stderr,
"Failed to enable IPv4 masquerading (NAT). Will continue anyway.\n");
}
}
}
uid_t uid = getuid ();
#ifdef HAVE_SETRESUID
if (0 != setresuid (uid, uid, uid))
{
fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
global_ret = 2;
goto cleanup;
}
#else
if (0 != (setuid (uid) | seteuid (uid)))
{
fprintf (stderr, "Failed to setuid: %s\n", strerror (errno));
global_ret = 2;
goto cleanup;
}
#endif
if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
{
fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",
strerror (errno));
/* no exit, we might as well die with SIGPIPE should it ever happen */
}
run (fd_tun);
global_ret = 0;
cleanup:
(void) close (fd_tun);
return global_ret;
}