int main(int argc, char *argv[])
{
/* We need to keep these env variables since systemd uses them for socket
* activation
*/
static const char *keep_env[] = {
"LISTEN_FDS",
"LISTEN_PID",
NULL
};
const char *root, *cwd, *env, *uid_str, *gid_str, *exe;
char **args;
uid_t uid;
gid_t *gids;
size_t n_gids;
exit_if(argc < 7,
"Usage: %s /path/to/root /work/directory /env/file uid gid[,gid...] /to/exec [args ...]", argv[0]);
root = argv[1];
cwd = argv[2];
env = argv[3];
uid_str = argv[4];
uid = atoi(uid_str);
gid_str = argv[5];
args = &argv[6];
exe = args[0];
parse_gids(gid_str, &n_gids, &gids);
load_env(env, keep_env);
pexit_if(chroot(root) == -1, "Chroot \"%s\" failed", root);
pexit_if(chdir(cwd) == -1, "Chdir \"%s\" failed", cwd);
pexit_if(gids[0] > 0 && setresgid(gids[0], gids[0], gids[0]) == -1,
"Setresgid \"%s\" failed", gid_str);
pexit_if(n_gids > 1 && setgroups(n_gids - 1, &gids[1]) == -1,
"Setgroups \"%s\" failed", gid_str);
pexit_if(uid > 0 && setresuid(uid, uid, uid) == -1,
"Setresuid \"%s\" failed", uid_str);
/* XXX(vc): note that since execvp() is happening post-chroot, the
* app's environment settings correctly affect the PATH search.
* This is why execvpe() isn't being used, we manipulate the environment
* manually then let it potentially affect execvp(). execvpe() simply
* passes the environment to execve() _after_ performing the search, not
* what we want here. */
pexit_if(execvp(exe, args) == -1 &&
errno != ENOENT && errno != EACCES,
"Exec of \"%s\" failed", exe);
diag(exe);
return EXIT_FAILURE;
}
int startup(int argc, char* argv[])
{
const char* tmp;
const char* end;
const char* cwdstr;
char* ptr;
unsigned long session_timeout;
unsigned startup_code;
if ((tmp = getenv("TCPLOCALIP")) == 0) FAIL("Missing $TCPLOCALIP.");
if (!parse_localip(tmp)) FAIL("Could not parse $TCPLOCALIP.");
if ((tmp = getenv("TCPREMOTEIP")) == 0) FAIL("Missing $TCPREMOTEIP.");
if (!parse_remoteip(tmp)) FAIL("Could not parse $TCPREMOTEIP.");
if ((tmp = getenv("UID")) == 0) FAIL("Missing $UID.");
if (!(uid = strtou(tmp, &end)) || *end) FAIL("Invalid $UID.");
if ((tmp = getenv("GID")) == 0) FAIL("Missing $GID.");
if (!(gid = strtou(tmp, &end)) || *end) FAIL("Invalid $GID.");
if ((home = getenv("HOME")) == 0) FAIL("Missing $HOME.");
if ((tmp = getenv("GIDS")) != 0 && !parse_gids(tmp))
FAIL("Could not parse or set supplementary group IDs.");
/* Strip off trailing slashes in $HOME */
ptr = (char*)home + strlen(home)-1;
while (ptr > home && *ptr == '/') *ptr-- = 0;
if ((user = getenv("USER")) == 0) FAIL("Missing $USER.");
if ((group = getenv("GROUP")) == 0) group = "mygroup";
if (chdir(home)) FAIL("Could not chdir to $HOME.");
if (!load_tables()) FAIL("Loading startup tables failed.");
if (getenv("CHROOT") != 0) {
cwdstr = "/";
if (chroot(".")) FAIL("Could not chroot.");
}
else if (getenv("SOFTCHROOT") != 0) {
cwdstr = "/";
}
else {
cwdstr = home;
if (chdir("/")) FAIL("Could not chdir to '/'.");
}
if (!str_copys(&cwd, cwdstr)) FAIL("Could not set CWD string");
if (setgid(gid)) FAIL("Could not set GID.");
if (setuid(uid)) FAIL("Could not set UID.");
if ((user_len = strlen(user)) > MAX_NAME_LEN) {
user_len = MAX_NAME_LEN;
((char*)user)[MAX_NAME_LEN] = 0;
}
if ((group_len = strlen(group)) > MAX_NAME_LEN) {
group_len = MAX_NAME_LEN;
((char*)group)[MAX_NAME_LEN] = 0;
}
lockhome = (getenv("LOCKHOME") != 0);
nodotfiles = (getenv("NODOTFILES") != 0);
list_options = (nodotfiles ? 0 : PATH_MATCH_DOTFILES);
session_timeout = 0;
if ((tmp = getenv("SESSION_TIMEOUT")) != 0)
session_timeout = strtou(tmp, &tmp);
alarm(session_timeout);
connect_timeout = timeout;
if ((tmp = getenv("CONNECT_TIMEOUT")) != 0)
connect_timeout = strtou(tmp, &tmp);
if ((tmp = getenv("TWOFTPD_BIND_PORT_FD")) != 0) {
if ((bind_port_fd = strtou(tmp, &end)) == 0 || *end != 0)
FAIL("Invalid $TWOFTPD_BIND_PORT_FD");
}
else
bind_port_fd = -1;
startup_code = (getenv("AUTHENTICATED") != 0) ? 230 : 220;
if ((tmp = getenv("BANNER")) != 0) show_banner(startup_code, tmp);
message_file = getenv("MESSAGEFILE");
show_message_file(startup_code);
return respond(startup_code, 1, "Ready to transfer files.");
(void)argc;
(void)argv;
}
