static Channel *
server_request_direct_tcpip(struct ssh *ssh)
{
Channel *c = NULL;
char *target, *originator;
u_int target_port, originator_port;
int r;
if ((r = sshpkt_get_cstring(ssh, &target, NULL)) != 0 ||
(r = sshpkt_get_u32(ssh, &target_port)) != 0 ||
(r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 ||
(r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
debug("server_request_direct_tcpip: originator %s port %d, target %s "
"port %d", originator, originator_port, target, target_port);
/* XXX fine grained permissions */
if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
!no_port_forwarding_flag) {
c = channel_connect_to_port(ssh, target, target_port,
"direct-tcpip", "direct-tcpip");
} else {
logit("refused local port forward: "
"originator %s port %d, target %s port %d",
originator, originator_port, target, target_port);
}
free(originator);
free(target);
return c;
}
static int
server_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
{
Channel *c = NULL;
char *ctype = 0;
int r;
u_int rchan, rmaxpack, rwindow;
size_t len;
if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 ||
(r = sshpkt_get_u32(ssh, &rchan)) != 0 ||
(r = sshpkt_get_u32(ssh, &rwindow)) != 0 ||
(r = sshpkt_get_u32(ssh, &rmaxpack)) != 0)
goto out;
debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
ctype, rchan, rwindow, rmaxpack);
if (strcmp(ctype, "session") == 0) {
c = server_request_session(ssh);
} else if (strcmp(ctype, "direct-tcpip") == 0) {
c = server_request_direct_tcpip(ssh);
} else if (strcmp(ctype, "*****@*****.**") == 0) {
c = server_request_direct_streamlocal(ssh);
} else if (strcmp(ctype, "*****@*****.**") == 0) {
c = server_request_tun(ssh);
}
if (c != NULL) {
debug("server_input_channel_open: confirm %s", ctype);
c->remote_id = rchan;
c->remote_window = rwindow;
c->remote_maxpacket = rmaxpack;
if (c->type != SSH_CHANNEL_CONNECTING) {
if ((r = sshpkt_start(ssh,
SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
(r = sshpkt_put_u32(ssh, c->self)) != 0 ||
(r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
(r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0||
(r = sshpkt_send(ssh)) != 0)
goto out;
}
} else {
debug("server_input_channel_open: failure %s", ctype);
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
(r = sshpkt_put_u32(ssh, rchan)) != 0 ||
(r = sshpkt_put_u32(ssh,
SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 ||
(!(ssh->compat & SSH_BUG_OPENFAILURE) &&
(r = sshpkt_put_cstring(ssh, "open failed")) != 0) ||
(!(ssh->compat & SSH_BUG_OPENFAILURE) &&
(r = sshpkt_put_cstring(ssh, "")) != 0) ||
(r = sshpkt_send(ssh)) != 0)
goto out;
}
r = 0;
out:
free(ctype);
return r;
}
char *
ssh_packet_get_cstring(struct ssh *ssh, u_int *length_ptr)
{
int r;
size_t len;
char *val;
if ((r = sshpkt_get_cstring(ssh, &val, &len)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
if (length_ptr != NULL)
*length_ptr = (u_int)len;
return val;
}
static int
userauth_passwd(struct ssh *ssh)
{
char *password;
int authenticated = 0, r;
u_char change;
size_t len;
if ((r = sshpkt_get_u8(ssh, &change)) != 0 ||
(r = sshpkt_get_cstring(ssh, &password, &len)) != 0 ||
(change && (r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0) ||
(r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
if (change)
logit("password change not supported");
else if (PRIVSEP(auth_password(ssh, password)) == 1)
authenticated = 1;
explicit_bzero(password, len);
free(password);
return authenticated;
}
int
kex_input_ext_info(int type, u_int32_t seq, void *ctxt)
{
struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
u_int32_t i, ninfo;
char *name, *val, *found;
int r;
debug("SSH2_MSG_EXT_INFO received");
ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_protocol_error);
if ((r = sshpkt_get_u32(ssh, &ninfo)) != 0)
return r;
for (i = 0; i < ninfo; i++) {
if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0)
return r;
if ((r = sshpkt_get_cstring(ssh, &val, NULL)) != 0) {
free(name);
return r;
}
debug("%s: %s=<%s>", __func__, name, val);
if (strcmp(name, "server-sig-algs") == 0) {
found = match_list("rsa-sha2-256", val, NULL);
if (found) {
kex->rsa_sha2 = 256;
free(found);
}
found = match_list("rsa-sha2-512", val, NULL);
if (found) {
kex->rsa_sha2 = 512;
free(found);
}
}
free(name);
free(val);
}
return sshpkt_get_end(ssh);
}
static int
server_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
{
Channel *c;
int r, success = 0;
u_int id;
u_char reply;
char *rtype = NULL;
if ((r = sshpkt_get_u32(ssh, &id)) != 0 ||
(r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
(r = sshpkt_get_u8(ssh, &reply)) != 0)
goto out;
debug("server_input_channel_req: channel %u request %s reply %d",
id, rtype, reply);
if ((c = channel_lookup(id)) == NULL)
ssh_packet_disconnect(ssh, "server_input_channel_req: "
"unknown channel %u", id);
if (!strcmp(rtype, "*****@*****.**")) {
if ((r = sshpkt_get_end(ssh)) != 0)
goto out;
chan_rcvd_eow(c);
} else if ((c->type == SSH_CHANNEL_LARVAL ||
c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
success = session_input_channel_req(c, rtype);
if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
if ((r = sshpkt_start(ssh, success ? SSH2_MSG_CHANNEL_SUCCESS :
SSH2_MSG_CHANNEL_FAILURE)) != 0 ||
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
}
r = 0;
out:
if (rtype)
free(rtype);
return r;
}
/*ARGSUSED*/
static int
input_service_request(int type, u_int32_t seq, struct ssh *ssh)
{
struct authctxt *authctxt = ssh->authctxt;
char *service = NULL;
int r, acceptit = 0;
if ((r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
if (authctxt == NULL)
fatal("input_service_request: no authctxt");
if (strcmp(service, "ssh-userauth") == 0) {
if (!authctxt->success) {
acceptit = 1;
/* now we can handle user-auth requests */
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST,
&input_userauth_request);
}
}
/* XXX all other service requests are denied */
if (acceptit) {
if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_ACCEPT)) != 0 ||
(r = sshpkt_put_cstring(ssh, service)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
ssh_packet_write_wait(ssh);
} else {
debug("bad service request %s", service);
ssh_packet_disconnect(ssh, "bad service request %s", service);
}
r = 0;
out:
free(service);
return r;
}
/*ARGSUSED*/
static int
input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
{
struct authctxt *authctxt = ssh->authctxt;
struct authmethod *m = NULL;
char *user = NULL, *service = NULL, *method = NULL, *style = NULL;
int r, authenticated = 0;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
if ((r = sshpkt_get_cstring(ssh, &user, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &method, NULL)) != 0)
goto out;
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
}
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->user = xstrdup(user);
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner(ssh);
if (auth2_setup_methods_lists(authctxt) != 0)
ssh_packet_disconnect(ssh,
"no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
ssh_packet_disconnect(ssh, "Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(ssh);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(ssh);
}
userauth_finish(ssh, authenticated, method, NULL);
r = 0;
out:
free(service);
free(user);
free(method);
return r;
}
static int
userauth_hostbased(struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
struct sshbuf *b;
struct sshkey *key = NULL;
char *pkalg, *cuser, *chost;
u_char *pkblob, *sig;
size_t alen, blen, slen;
int r, pktype, authenticated = 0;
if (!authctxt->valid) {
debug2("%s: disabled because of invalid user", __func__);
return 0;
}
/* XXX use sshkey_froms() */
if ((r = sshpkt_get_cstring(ssh, &pkalg, &alen)) != 0 ||
(r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 ||
(r = sshpkt_get_cstring(ssh, &chost, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &cuser, NULL)) != 0 ||
(r = sshpkt_get_string(ssh, &sig, &slen)) != 0)
fatal("%s: packet parsing: %s", __func__, ssh_err(r));
debug("%s: cuser %s chost %s pkalg %s slen %zu", __func__,
cuser, chost, pkalg, slen);
#ifdef DEBUG_PK
debug("signature:");
sshbuf_dump_data(sig, siglen, stderr);
#endif
pktype = sshkey_type_from_name(pkalg);
if (pktype == KEY_UNSPEC) {
/* this is perfectly legal */
logit("%s: unsupported public key algorithm: %s",
__func__, pkalg);
goto done;
}
if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) {
error("%s: key_from_blob: %s", __func__, ssh_err(r));
goto done;
}
if (key == NULL) {
error("%s: cannot decode key: %s", __func__, pkalg);
goto done;
}
if (key->type != pktype) {
error("%s: type mismatch for decoded key "
"(received %d, expected %d)", __func__, key->type, pktype);
goto done;
}
if (sshkey_type_plain(key->type) == KEY_RSA &&
(ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
error("Refusing RSA key because peer uses unsafe "
"signature format");
goto done;
}
if (match_pattern_list(sshkey_ssh_name(key),
options.hostbased_key_types, 0) != 1) {
logit("%s: key type %s not in HostbasedAcceptedKeyTypes",
__func__, sshkey_type(key));
goto done;
}
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
/* reconstruct packet */
if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 ||
(r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
(r = sshbuf_put_cstring(b, authctxt->user)) != 0 ||
(r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
(r = sshbuf_put_cstring(b, "hostbased")) != 0 ||
(r = sshbuf_put_string(b, pkalg, alen)) != 0 ||
(r = sshbuf_put_string(b, pkblob, blen)) != 0 ||
(r = sshbuf_put_cstring(b, chost)) != 0 ||
(r = sshbuf_put_cstring(b, cuser)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
#ifdef DEBUG_PK
sshbuf_dump(b, stderr);
#endif
auth2_record_info(authctxt,
"client user \"%.100s\", client host \"%.100s\"", cuser, chost);
/* test for allowed key and correct signature */
authenticated = 0;
if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
PRIVSEP(sshkey_verify(key, sig, slen,
sshbuf_ptr(b), sshbuf_len(b), pkalg, ssh->compat)) == 0)
authenticated = 1;
auth2_record_key(authctxt, authenticated, key);
sshbuf_free(b);
done:
debug2("%s: authenticated %d", __func__, authenticated);
sshkey_free(key);
free(pkalg);
free(pkblob);
free(cuser);
free(chost);
free(sig);
return authenticated;
}
static int
input_userauth_info_response(int type, u_int32_t seq, struct ssh *ssh)
{
struct authctxt *authctxt = ssh->authctxt;
struct kbdintctxt *kbdintctxt;
int authenticated = 0, res;
int r;
u_int i, nresp;
const char *devicename = NULL;
char **response = NULL;
if (authctxt == NULL)
fatal("input_userauth_info_response: no authctxt");
kbdintctxt = authctxt->kbdintctxt;
if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
fatal("input_userauth_info_response: no kbdintctxt");
if (kbdintctxt->device == NULL)
fatal("input_userauth_info_response: no device");
authctxt->postponed = 0; /* reset */
if ((r = sshpkt_get_u32(ssh, &nresp)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
if (nresp != kbdintctxt->nreq)
fatal("input_userauth_info_response: wrong number of replies");
if (nresp > 100)
fatal("input_userauth_info_response: too many replies");
if (nresp > 0) {
response = xcalloc(nresp, sizeof(char *));
for (i = 0; i < nresp; i++)
if ((r = sshpkt_get_cstring(ssh, &response[i],
NULL)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
}
if ((r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
for (i = 0; i < nresp; i++) {
explicit_bzero(response[i], strlen(response[i]));
free(response[i]);
}
free(response);
switch (res) {
case 0:
/* Success! */
authenticated = authctxt->valid ? 1 : 0;
break;
case 1:
/* Authentication needs further interaction */
if (send_userauth_info_request(ssh) == 1)
authctxt->postponed = 1;
break;
default:
/* Failure! */
break;
}
devicename = kbdintctxt->device->name;
if (!authctxt->postponed) {
if (authenticated) {
auth2_challenge_stop(ssh);
} else {
/* start next device */
/* may set authctxt->postponed */
auth2_challenge_start(ssh);
}
}
userauth_finish(ssh, authenticated, "keyboard-interactive",
devicename);
return 0;
}
static int
server_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
{
char *rtype = NULL;
u_char want_reply;
int r, success = 0, allocated_listen_port = 0;
struct sshbuf *resp = NULL;
if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
(r = sshpkt_get_u8(ssh, &want_reply)) != 0)
goto out;
debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
/* -R style forwarding */
if (strcmp(rtype, "tcpip-forward") == 0) {
struct authctxt *authctxt = ssh->authctxt;
struct Forward fwd;
if (authctxt->pw == NULL || !authctxt->valid)
fatal("server_input_global_request: no/invalid user");
memset(&fwd, 0, sizeof(fwd));
if ((r = sshpkt_get_cstring(ssh, &fwd.listen_host, NULL)) != 0 ||
(r = sshpkt_get_u32(ssh, &fwd.listen_port)) != 0)
goto out;
debug("server_input_global_request: tcpip-forward listen %s port %d",
fwd.listen_host, fwd.listen_port);
/* check permissions */
if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
no_port_forwarding_flag ||
(!want_reply && fwd.listen_port == 0) ||
(fwd.listen_port != 0 && fwd.listen_port < IPPORT_RESERVED &&
authctxt->pw->pw_uid != 0)) {
success = 0;
ssh_packet_send_debug(ssh,
"Server has disabled port forwarding.");
} else {
/* Start listening on the port */
success = channel_setup_remote_fwd_listener(ssh, &fwd,
&allocated_listen_port, &options.fwd_opts);
}
free(fwd.listen_host);
if ((resp = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new", __func__);
if (allocated_listen_port != 0 &&
(r = sshbuf_put_u32(resp, allocated_listen_port)) != 0)
fatal("%s: sshbuf_put_u32: %s", __func__, ssh_err(r));
} else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
struct Forward fwd;
memset(&fwd, 0, sizeof(fwd));
if ((r = sshpkt_get_cstring(ssh, &fwd.listen_host, NULL)) != 0 ||
(r = sshpkt_get_u32(ssh, &fwd.listen_port)) != 0)
goto out;
debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
fwd.listen_host, fwd.listen_port);
success = channel_cancel_rport_listener(&fwd);
free(fwd.listen_host);
} else if (strcmp(rtype, "*****@*****.**") == 0) {
struct Forward fwd;
memset(&fwd, 0, sizeof(fwd));
if ((r = sshpkt_get_cstring(ssh, &fwd.listen_path, NULL)) != 0)
goto out;
debug("server_input_global_request: streamlocal-forward listen path %s",
fwd.listen_path);
/* check permissions */
if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
|| no_port_forwarding_flag) {
success = 0;
ssh_packet_send_debug(ssh, "Server has disabled port forwarding.");
} else {
/* Start listening on the socket */
success = channel_setup_remote_fwd_listener(ssh,
&fwd, NULL, &options.fwd_opts);
}
free(fwd.listen_path);
} else if (strcmp(rtype, "*****@*****.**") == 0) {
struct Forward fwd;
memset(&fwd, 0, sizeof(fwd));
if ((r = sshpkt_get_cstring(ssh, &fwd.listen_path, NULL)) != 0)
goto out;
debug("%s: cancel-streamlocal-forward path %s", __func__,
fwd.listen_path);
success = channel_cancel_rport_listener(&fwd);
free(fwd.listen_path);
} else if (strcmp(rtype, "*****@*****.**") == 0) {
no_more_sessions = 1;
success = 1;
} else if (strcmp(rtype, "*****@*****.**") == 0) {
success = server_input_hostkeys_prove(&resp);
}
if (want_reply) {
if ((r = sshpkt_start(ssh, success ?
SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE)) != 0 ||
(success && resp != NULL &&
(r = sshpkt_put(ssh, sshbuf_ptr(resp), sshbuf_len(resp)))
!= 0) ||
(r = sshpkt_send(ssh)) != 0)
goto out;
ssh_packet_write_wait(ssh);
}
r = 0;
out:
free(rtype);
sshbuf_free(resp);
return r;
}
