*/
/**
- * @file exit/gnunet-helper-exit.c
+ * @file exit/gnunet-helper-exit.c
*
* @brief the helper for exit nodes. Opens a virtual
* network-interface, sends data received on the if to stdout, sends
/**
* Need 'struct GNUNET_MessageHeader'.
*/
+#include "gnunet_crypto_lib.h"
#include "gnunet_common.h"
/**
*/
#include "gnunet_protocols.h"
+/**
+ * Should we print (interesting|debug) messages that can happen during
+ * normal operation?
+ */
+#define DEBUG GNUNET_NO
+
/**
* Maximum size of a GNUnet message (GNUNET_SERVER_MAX_MESSAGE_SIZE)
*/
/**
* Path to 'sysctl' binary.
*/
-#define SBIN_SYSCTL "/sbin/sysctl"
+static const char *sbin_sysctl;
/**
* Path to 'iptables' binary.
*/
-#define SBIN_IPTABLES "/sbin/iptables"
+static const char *sbin_iptables;
#ifndef _LINUX_IN6_H
struct in6_ifreq
{
struct in6_addr ifr6_addr;
- uint32_t ifr6_prefixlen;
- unsigned int ifr6_ifindex;
+ uint32_t ifr6_prefixlen; /* __u32 in the original */
+ int ifr6_ifindex;
};
#endif
+/**
+ * Open '/dev/null' and make the result the given
+ * file descriptor.
+ *
+ * @param target_fd desired FD to point to /dev/null
+ * @param flags open flags (O_RDONLY, O_WRONLY)
+ */
+static void
+open_dev_null (int target_fd,
+ int flags)
+{
+ int fd;
+
+ fd = open ("/dev/null", flags);
+ if (-1 == fd)
+ abort ();
+ if (fd == target_fd)
+ return;
+ if (-1 == dup2 (fd, target_fd))
+ {
+ (void) close (fd);
+ abort ();
+ }
+ (void) close (fd);
+}
+
/**
* Run the given command and wait for it to complete.
- *
+ *
* @param file name of the binary to run
* @param cmd command line arguments (as given to 'execv')
* @return 0 on success, 1 on any error
*/
static int
-fork_and_exec (const char *file,
+fork_and_exec (const char *file,
char *const cmd[])
{
int status;
pid = fork ();
if (-1 == pid)
{
- fprintf (stderr,
- "fork failed: %s\n",
+ fprintf (stderr,
+ "fork failed: %s\n",
strerror (errno));
return 1;
}
if (0 == pid)
{
/* we are the child process */
+ /* close stdin/stdout to not cause interference
+ with the helper's main protocol! */
+ (void) close (0);
+ open_dev_null (0, O_RDONLY);
+ (void) close (1);
+ open_dev_null (1, O_WRONLY);
(void) execv (file, cmd);
/* can only get here on error */
- fprintf (stderr,
- "exec `%s' failed: %s\n",
+ fprintf (stderr,
+ "exec `%s' failed: %s\n",
file,
strerror (errno));
_exit (1);
}
/* keep running waitpid as long as the only error we get is 'EINTR' */
while ( (-1 == (ret = waitpid (pid, &status, 0))) &&
- (errno == EINTR) );
+ (errno == EINTR) );
if (-1 == ret)
{
- fprintf (stderr,
- "waitpid failed: %s\n",
+ fprintf (stderr,
+ "waitpid failed: %s\n",
strerror (errno));
return 1;
}
if (fd >= FD_SETSIZE)
{
fprintf (stderr, "File descriptor to large: %d", fd);
+ (void) close (fd);
return -1;
}
if (-1 == ioctl (fd, TUNSETIFF, (void *) &ifr))
{
- fprintf (stderr, "Error with ioctl on `%s': %s\n", "/dev/net/tun",
+ fprintf (stderr,
+ "Error with ioctl on `%s': %s\n", "/dev/net/tun",
strerror (errno));
(void) close (fd);
return -1;
set_address6 (const char *dev, const char *address, unsigned long prefix_len)
{
struct ifreq ifr;
- struct in6_ifreq ifr6;
struct sockaddr_in6 sa6;
int fd;
+ struct in6_ifreq ifr6;
/*
* parse the new address
*/
memset (&sa6, 0, sizeof (struct sockaddr_in6));
sa6.sin6_family = AF_INET6;
- if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
+ if (1 != inet_pton (AF_INET6, address, &sa6.sin6_addr))
{
fprintf (stderr, "Failed to parse address `%s': %s\n", address,
strerror (errno));
}
else if (0 == buftun_size)
{
+#if DEBUG
fprintf (stderr, "EOF on tun\n");
+#endif
shutdown (fd_tun, SHUT_RD);
shutdown (1, SHUT_WR);
read_open = 0;
if (-1 == written)
{
- fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
+#if !DEBUG
+ if (errno != EPIPE)
+#endif
+ fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
shutdown (fd_tun, SHUT_RD);
shutdown (1, SHUT_WR);
read_open = 0;
}
else if (0 == bufin_size)
{
+#if DEBUG
fprintf (stderr, "EOF on stdin\n");
+#endif
shutdown (0, SHUT_RD);
shutdown (fd_tun, SHUT_WR);
write_open = 0;
* Open VPN tunnel interface.
*
* @param argc must be 6
- * @param argv 0: binary name ("gnunet-helper-vpn")
- * 1: tunnel interface name ("gnunet-vpn")
- * 2: IPv4 "physical" interface name ("eth0"), or "%" to not do IPv4 NAT
+ * @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
if (7 != argc)
{
- fprintf (stderr, "Fatal: must supply 5 arguments!\n");
+ fprintf (stderr, "Fatal: must supply 6 arguments!\n");
return 1;
}
if ( (0 == strcmp (argv[3], "-")) &&
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\n");
+ 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;
}
{
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);
+ }
+ 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,
+ if (0 != fork_and_exec (sbin_sysctl,
sysctl_args))
{
fprintf (stderr,
"Failed to enable IPv6 forwarding. Will continue anyway.\n");
- }
+ }
}
}
{
const char *address = argv[5];
const char *mask = argv[6];
-
+
set_address4 (dev, address, mask);
}
{
{
"sysctl", "-w", "net.ipv4.ip_forward=1", NULL
};
- if (0 != fork_and_exec (SBIN_SYSCTL,
+ 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], "%"))
+ 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,
+ 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))
run (fd_tun);
global_ret = 0;
cleanup:
- close (fd_tun);
+ (void) close (fd_tun);
return global_ret;
}
projects / oweals / gnunet.git / blobdiff