static ssh_channel pkd_channel_openreq_cb(ssh_session s,
void *userdata) {
ssh_channel c = NULL;
ssh_channel *out = (ssh_channel *) userdata;
/* assumes pubkey authentication has already succeeded */
pkdout("pkd_channel_openreq_cb\n");
c = ssh_channel_new(s);
if (c == NULL) {
pkderr("ssh_channel_new: %s\n", ssh_get_error(s));
return NULL;
}
ssh_callbacks_init(&pkd_channel_cb);
pkd_channel_cb.userdata = userdata;
if (ssh_set_channel_callbacks(c, &pkd_channel_cb) != SSH_OK) {
pkderr("ssh_set_channel_callbacks: %s\n", ssh_get_error(s));
ssh_channel_free(c);
c = NULL;
}
*out = c;
return c;
}
static void *pkd_main(void *args) {
int rc = -1;
struct pkd_daemon_args *a = (struct pkd_daemon_args *) args;
struct sigaction act = { .sa_handler = pkd_sighandler, };
pkd_state.server_fd = -1;
pkd_state.req_exec_received = 0;
pkd_state.close_received = 0;
pkd_state.eof_received = 0;
/* SIGUSR1 is used to interrupt 'pkd_accept_fd'. */
rc = sigaction(SIGUSR1, &act, NULL);
if (rc != 0) {
pkderr("sigaction: %d\n", rc);
goto out;
}
rc = pkd_init_libssh();
if (rc != 0) {
pkderr("pkd_init_libssh: %d\n", rc);
goto out;
}
rc = pkd_init_server_fd(1234);
if (rc != 0) {
pkderr("pkd_init_server_fd: %d\n", rc);
goto out;
}
ctx.pkd_ready = 1;
while (ctx.keep_going != 0) {
int fd = pkd_accept_fd();
if (fd < 0) {
if (ctx.keep_going != 0) {
pkderr("pkd_accept_fd");
rc = -1;
} else {
rc = 0;
}
break;
}
rc = pkd_exec_hello(fd, a);
if (rc != 0) {
pkderr("pkd_exec_hello: %d\n", rc);
break;
}
}
close(pkd_state.server_fd);
pkd_state.server_fd = -1;
out:
ctx.rc = rc;
return NULL;
}
static int pkd_exec_hello(int fd, struct pkd_daemon_args *args) {
int rc = -1;
ssh_bind b = NULL;
ssh_session s = NULL;
ssh_event e = NULL;
ssh_channel c = NULL;
enum ssh_bind_options_e opts = -1;
int level = args->opts.libssh_log_level;
enum pkd_hostkey_type_e type = args->type;
const char *hostkeypath = args->hostkeypath;
pkd_state.eof_received = 0;
pkd_state.close_received = 0;
pkd_state.req_exec_received = 0;
b = ssh_bind_new();
if (b == NULL) {
pkderr("ssh_bind_new\n");
goto outclose;
}
if (type == PKD_RSA) {
opts = SSH_BIND_OPTIONS_RSAKEY;
} else if (type == PKD_ED25519) {
opts = SSH_BIND_OPTIONS_HOSTKEY;
#ifdef HAVE_DSA
} else if (type == PKD_DSA) {
opts = SSH_BIND_OPTIONS_DSAKEY;
#endif
} else if (type == PKD_ECDSA) {
opts = SSH_BIND_OPTIONS_ECDSAKEY;
} else {
pkderr("unknown kex algorithm: %d\n", type);
rc = -1;
goto outclose;
}
rc = ssh_bind_options_set(b, opts, hostkeypath);
if (rc != 0) {
pkderr("ssh_bind_options_set: %s\n", ssh_get_error(b));
goto outclose;
}
rc = ssh_bind_options_set(b, SSH_BIND_OPTIONS_LOG_VERBOSITY, &level);
if (rc != 0) {
pkderr("ssh_bind_options_set log verbosity: %s\n", ssh_get_error(b));
goto outclose;
}
s = ssh_new();
if (s == NULL) {
pkderr("ssh_new\n");
goto outclose;
}
/*
* ssh_bind_accept loads host key as side-effect. If this
* succeeds, the given 'fd' will be closed upon 'ssh_free(s)'.
*/
rc = ssh_bind_accept_fd(b, s, fd);
if (rc != SSH_OK) {
pkderr("ssh_bind_accept_fd: %s\n", ssh_get_error(b));
goto outclose;
}
/* accept only publickey-based auth */
ssh_set_auth_methods(s, SSH_AUTH_METHOD_PUBLICKEY);
/* initialize callbacks */
ssh_callbacks_init(&pkd_server_cb);
pkd_server_cb.userdata = &c;
rc = ssh_set_server_callbacks(s, &pkd_server_cb);
if (rc != SSH_OK) {
pkderr("ssh_set_server_callbacks: %s\n", ssh_get_error(s));
goto out;
}
/* first do key exchange */
rc = ssh_handle_key_exchange(s);
if (rc != SSH_OK) {
pkderr("ssh_handle_key_exchange: %s\n", ssh_get_error(s));
goto out;
}
/* setup and pump event to carry out exec channel */
e = ssh_event_new();
if (e == NULL) {
pkderr("ssh_event_new\n");
goto out;
}
rc = ssh_event_add_session(e, s);
if (rc != SSH_OK) {
pkderr("ssh_event_add_session\n");
goto out;
}
/* poll until exec channel established */
while ((ctx.keep_going != 0) &&
(rc != SSH_ERROR) && (pkd_state.req_exec_received == 0)) {
rc = ssh_event_dopoll(e, -1 /* infinite timeout */);
}
if (rc == SSH_ERROR) {
pkderr("ssh_event_dopoll\n");
goto out;
} else if (c == NULL) {
pkderr("poll loop exited but exec channel not ready\n");
rc = -1;
goto out;
}
rc = ssh_channel_write(c, "hello\n", 6); /* XXX: customizable payloads */
if (rc != 6) {
pkderr("ssh_channel_write partial (%d)\n", rc);
}
rc = ssh_channel_request_send_exit_status(c, 0);
if (rc != SSH_OK) {
pkderr("ssh_channel_request_send_exit_status: %s\n",
ssh_get_error(s));
goto out;
}
rc = ssh_channel_send_eof(c);
if (rc != SSH_OK) {
pkderr("ssh_channel_send_eof: %s\n", ssh_get_error(s));
goto out;
}
rc = ssh_channel_close(c);
if (rc != SSH_OK) {
pkderr("ssh_channel_close: %s\n", ssh_get_error(s));
goto out;
}
while ((ctx.keep_going != 0) &&
(pkd_state.eof_received == 0) &&
(pkd_state.close_received == 0)) {
rc = ssh_event_dopoll(e, 1000 /* milliseconds */);
if (rc == SSH_ERROR) {
/* log, but don't consider this fatal */
pkdout("ssh_event_dopoll for eof + close: %s\n", ssh_get_error(s));
rc = 0;
break;
} else {
rc = 0;
}
}
while ((ctx.keep_going != 0) &&
(ssh_is_connected(s))) {
rc = ssh_event_dopoll(e, 1000 /* milliseconds */);
if (rc == SSH_ERROR) {
/* log, but don't consider this fatal */
pkdout("ssh_event_dopoll for session connection: %s\n", ssh_get_error(s));
rc = 0;
break;
} else {
rc = 0;
}
}
goto out;
outclose:
close(fd);
out:
if (c != NULL) {
ssh_channel_free(c);
}
if (e != NULL) {
ssh_event_remove_session(e, s);
ssh_event_free(e);
}
if (s != NULL) {
ssh_disconnect(s);
ssh_free(s);
}
if (b != NULL) {
ssh_bind_free(b);
}
return rc;
}