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Code Issues Releases Wiki Activity

Server side refactor (+username/pubkey)

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This commit is contained in:
Nicolas Viennot 2013-06-10 21:30:01 -04:00
parent e0861e170a
commit e36905a646
2 changed files with 122 additions and 88 deletions
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207
tmate-ssh-server.c
View File

@ -11,6 +11,118 @@
#define SSH_GRACE_PERIOD 60
#define REPLY_DEFAULT 1
#define STEP_COMPLETE 2
typedef int (*bootstrap_step_cb)(struct tmate_ssh_client *client,
ssh_message msg);
static void bootstrap_step(struct tmate_ssh_client *client,
bootstrap_step_cb step)
{
ssh_message msg;
for (;;) {
msg = ssh_message_get(client->session);
switch (step(client, msg)) {
case STEP_COMPLETE:
return;
case REPLY_DEFAULT:
ssh_message_reply_default(msg);
}
ssh_message_free(msg);
}
}
static int user_auth_step(struct tmate_ssh_client *client,
ssh_message msg)
{
if (!msg)
tmate_fatal("Authentification error");
if (ssh_message_type(msg) != SSH_REQUEST_AUTH)
return REPLY_DEFAULT;
if (ssh_message_subtype(msg) != SSH_AUTH_METHOD_PUBLICKEY) {
ssh_message_auth_set_methods(msg, SSH_AUTH_METHOD_PUBLICKEY);
return REPLY_DEFAULT;
}
switch (ssh_message_auth_publickey_state(msg)) {
case SSH_PUBLICKEY_STATE_NONE:
ssh_message_auth_reply_pk_ok_simple(msg);
return 0;
case SSH_PUBLICKEY_STATE_VALID:
client->username = xstrdup(ssh_message_auth_user(msg));
if (ssh_pki_export_pubkey_base64(ssh_message_auth_pubkey(msg),
&client->pubkey) != SSH_OK)
tmate_fatal("error getting public key");
ssh_message_auth_reply_success(msg, 0);
return STEP_COMPLETE;
default:
return REPLY_DEFAULT;
}
}
static int channel_open_step(struct tmate_ssh_client *client,
ssh_message msg)
{
if (!msg)
tmate_fatal("Error getting channel");
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL_OPEN &&
ssh_message_subtype(msg) == SSH_CHANNEL_SESSION) {
client->channel = ssh_message_channel_request_open_reply_accept(msg);
if (!client->channel)
tmate_fatal("Error getting channel");
return STEP_COMPLETE;
}
return REPLY_DEFAULT;
}
static int init_client_step(struct tmate_ssh_client *client,
ssh_message msg)
{
if (!msg)
tmate_fatal("Error getting subsystem");
/* pty request */
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_PTY) {
client->winsize_pty.ws_col = ssh_message_channel_request_pty_width(msg);
client->winsize_pty.ws_row = ssh_message_channel_request_pty_height(msg);
ssh_message_channel_request_reply_success(msg);
return 0;
}
/* tmate subsystem request (master) */
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_SUBSYSTEM &&
!strcmp(ssh_message_channel_request_subsystem(msg), "tmate")) {
alarm(0);
ssh_message_channel_request_reply_success(msg);
tmate_spawn_slave_server(client);
/* never reached */
}
/* shell request (slave client) */
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_SHELL) {
alarm(0);
ssh_message_channel_request_reply_success(msg);
tmate_spawn_slave_client(client);
/* never reached */
}
return REPLY_DEFAULT;
}
static void client_bootstrap(struct tmate_ssh_client *client)
{
int auth = 0;
@ -19,108 +131,27 @@ static void client_bootstrap(struct tmate_ssh_client *client)
ssh_message msg;
int flag = 1;
setsockopt(ssh_get_fd(session), IPPROTO_TCP, TCP_NODELAY, &flag, sizeof(flag));
setsockopt(ssh_get_fd(session), IPPROTO_TCP, TCP_NODELAY,
&flag, sizeof(flag));
alarm(SSH_GRACE_PERIOD);
ssh_options_set(session, SSH_OPTIONS_COMPRESSION, "yes");
tmate_debug("Exchanging DH keys");
if (ssh_handle_key_exchange(session) < 0)
tmate_fatal("Error doing the key exchange");
tmate_debug("Authenticating with public key");
while (!auth) {
msg = ssh_message_get(session);
if (!msg)
tmate_fatal("Authentification error");
switch (ssh_message_type(msg)) {
case SSH_REQUEST_AUTH:
switch (ssh_message_subtype(msg)) {
case SSH_AUTH_METHOD_PUBLICKEY:
if (ssh_message_auth_publickey_state(msg) == SSH_PUBLICKEY_STATE_NONE)
ssh_message_auth_reply_pk_ok_simple(msg);
else if (ssh_message_auth_publickey_state(msg) == SSH_PUBLICKEY_STATE_VALID) {
ssh_message_auth_reply_success(msg, 0);
auth = 1;
}
break;
case SSH_AUTH_METHOD_NONE:
default:
ssh_message_auth_set_methods(msg, SSH_AUTH_METHOD_PUBLICKEY);
ssh_message_reply_default(msg);
break;
}
break;
default:
ssh_message_reply_default(msg);
}
ssh_message_free(msg);
}
bootstrap_step(client, user_auth_step);
tmate_debug("Opening channel");
while (!channel) {
msg = ssh_message_get(session);
if (!msg)
tmate_fatal("Error getting channel");
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL_OPEN &&
ssh_message_subtype(msg) == SSH_CHANNEL_SESSION) {
client->channel = channel = ssh_message_channel_request_open_reply_accept(msg);
if (!channel)
tmate_fatal("Error getting channel");
} else {
ssh_message_reply_default(msg);
}
ssh_message_free(msg);
}
bootstrap_step(client, channel_open_step);
tmate_debug("Getting client type");
bootstrap_step(client, init_client_step);
while (1) {
msg = ssh_message_get(session);
if (!msg)
tmate_fatal("Error getting subsystem");
/* subsystem request */
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_SUBSYSTEM &&
!strcmp(ssh_message_channel_request_subsystem(msg), "tmate")) {
alarm(0);
ssh_message_channel_request_reply_success(msg);
tmate_spawn_slave_server(client);
}
/* PTY request */
else if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_PTY) {
client->winsize_pty.ws_col = ssh_message_channel_request_pty_width(msg);
client->winsize_pty.ws_row = ssh_message_channel_request_pty_height(msg);
ssh_message_channel_request_reply_success(msg);
}
/* SHELL request */
else if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL &&
ssh_message_subtype(msg) == SSH_CHANNEL_REQUEST_SHELL) {
alarm(0);
ssh_message_channel_request_reply_success(msg);
tmate_spawn_slave_client(client);
}
/* Default */
else {
ssh_message_reply_default(msg);
}
ssh_message_free(msg);
}
/* never reached */
}
static void handle_sigchld(void)

3
tmate.h
View File

@ -67,6 +67,9 @@ struct tmate_ssh_client {
struct tmate_encoder *encoder;
struct tmate_decoder *decoder;
char *username;
char *pubkey;
struct winsize winsize_pty;
struct event ev_ssh;