/* ARGSUSED */
int
kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
{
struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
const u_char *ptr;
u_int i;
size_t dlen;
int r;
debug("SSH2_MSG_KEXINIT received");
if (kex == NULL)
return SSH_ERR_INVALID_ARGUMENT;
ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
ptr = sshpkt_ptr(ssh, &dlen);
if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
return r;
/* discard packet */
for (i = 0; i < KEX_COOKIE_LEN; i++)
if ((r = sshpkt_get_u8(ssh, NULL)) != 0)
return r;
for (i = 0; i < PROPOSAL_MAX; i++)
if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)
return r;
/*
* XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
* KEX method has the server move first, but a server might be using
* a custom method or one that we otherwise don't support. We should
* be prepared to remember first_kex_follows here so we can eat a
* packet later.
* XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means
* for cases where the server *doesn't* go first. I guess we should
* ignore it when it is set for these cases, which is what we do now.
*/
if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || /* first_kex_follows */
(r = sshpkt_get_u32(ssh, NULL)) != 0 || /* reserved */
(r = sshpkt_get_end(ssh)) != 0)
return r;
if (!(kex->flags & KEX_INIT_SENT))
if ((r = kex_send_kexinit(ssh)) != 0)
return r;
if ((r = kex_choose_conf(ssh)) != 0)
return r;
if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
return (kex->kex[kex->kex_type])(ssh);
return SSH_ERR_INTERNAL_ERROR;
}
u_int
ssh_packet_get_char(struct ssh *ssh)
{
u_char ch;
int r;
if ((r = sshpkt_get_u8(ssh, &ch)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
return ch;
}
/* ARGSUSED */
int
kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
{
Kex *kex = ssh->kex;
u_char *ptr;
u_int i;
size_t dlen;
int r;
debug("SSH2_MSG_KEXINIT received");
if (kex == NULL)
return SSH_ERR_INVALID_ARGUMENT;
ptr = sshpkt_ptr(ssh, &dlen);
if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
return r;
/* discard packet */
for (i = 0; i < KEX_COOKIE_LEN; i++)
if ((r = sshpkt_get_u8(ssh, NULL)) != 0)
return r;
for (i = 0; i < PROPOSAL_MAX; i++)
if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)
return r;
if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
(r = sshpkt_get_u32(ssh, NULL)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
return r;
if (!(kex->flags & KEX_INIT_SENT))
if ((r = kex_send_kexinit(ssh)) != 0)
return r;
if ((r = kex_choose_conf(ssh)) != 0)
return r;
if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
kex->kex[kex->kex_type] != NULL)
return (kex->kex[kex->kex_type])(ssh);
return SSH_ERR_INTERNAL_ERROR;
}
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;
}
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;
}
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;
}