#2

1 files changed, 728 insertions, 0 deletions

diff --git a/plugins/ssh/ssh.c b/plugins/ssh/ssh.c
new file mode 100644
index 0000000..442653d
--- /dev/null
+++ b/plugins/ssh/ssh.c
@@ -0,0 +1,728 @@
+/*
+ * ssh — libssh transport plugin (port 3232). INI: [transport.ssh].
+ *
+ * Links dynamically against libssh (LGPL-2.1+). See share/THIRD_PARTY_NOTICES.txt.
+ */
+#include "hybbx/plugin.h"
+#include "hybbx/service.h"
+#include "hybbx/session.h"
+#include "hybbx/socket.h"
+#include "hybbx/security_ban.h"
+#include "hybbx/ssh.h"
+#include "hybbx/traffic.h"
+#include "hybbx/util.h"
+#include "hybbx/log.h"
+
+#include <libssh/callbacks.h>
+#include <libssh/libssh.h>
+#include <libssh/server.h>
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <poll.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define SSH_CLIENT_POLL_MS 30000
+#define SSH_READ_BUF 512
+
+typedef struct ssh_client {
+    int fd;
+    ssh_session session;
+    ssh_channel channel;
+    ssh_event event;
+    hybbx_session_t *hbx_session;
+    int ssh_authenticated;
+    int auth_attempts;
+    hybbx_result_t last_rc;
+    volatile int shell_ready;
+    struct ssh_server_callbacks_struct server_cb;
+    struct ssh_channel_callbacks_struct channel_cb;
+} ssh_client_t;
+
+typedef struct ssh_client_ctx {
+    ssh_client_t *client;
+} ssh_client_ctx_t;
+
+extern const hybbx_transport_plugin_t hybbx_plugin_ssh;
+
+static hybbx_service_t *g_service;
+static hybbx_ssh_config_t g_config;
+static char g_hostkey_path[HYBBX_PATH_MAX];
+static pthread_t g_accept_thread;
+static int g_listen_v4 = -1;
+static int g_listen_v6 = -1;
+static volatile int g_ssh_running = 0;
+
+static hybbx_result_t ssh_plugin_stop(void);
+
+static int set_socket_options(int fd, int family)
+{
+    int on = 1;
+
+    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) != 0) {
+        return -1;
+    }
+
+    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) != 0) {
+        return -1;
+    }
+
+    hybbx_socket_nosigpipe(fd);
+
+#ifdef IPV6_V6ONLY
+    if (family == AF_INET6) {
+        if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) != 0) {
+            return -1;
+        }
+    }
+#else
+    (void)family;
+#endif
+
+    return 0;
+}
+
+static int create_listen_socket(int family, const char *bind_addr, unsigned port)
+{
+    int fd;
+    int rc;
+
+    fd = socket(family, SOCK_STREAM, 0);
+    if (fd < 0) {
+        return -1;
+    }
+
+    if (set_socket_options(fd, family) != 0) {
+        close(fd);
+        return -1;
+    }
+
+    if (family == AF_INET6) {
+        struct sockaddr_in6 addr6;
+
+        memset(&addr6, 0, sizeof(addr6));
+        addr6.sin6_family = AF_INET6;
+        addr6.sin6_port = htons((uint16_t)port);
+
+        if (inet_pton(AF_INET6, bind_addr, &addr6.sin6_addr) != 1) {
+            close(fd);
+            return -1;
+        }
+
+        rc = bind(fd, (struct sockaddr *)&addr6, sizeof(addr6));
+    } else {
+        struct sockaddr_in addr4;
+
+        memset(&addr4, 0, sizeof(addr4));
+        addr4.sin_family = AF_INET;
+        addr4.sin_port = htons((uint16_t)port);
+
+        if (inet_pton(AF_INET, bind_addr, &addr4.sin_addr) != 1) {
+            close(fd);
+            return -1;
+        }
+
+        rc = bind(fd, (struct sockaddr *)&addr4, sizeof(addr4));
+    }
+
+    if (rc != 0) {
+        close(fd);
+        return -1;
+    }
+
+    if (listen(fd, 16) != 0) {
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+/*
+ * SSH wire authentication only — accepts any username/password so the client
+ * can open a shell channel. HyBBX login (guest auto-login or /login prompt)
+ * follows [auth] in hybbx.ini, same as telnet.
+ */
+static int ssh_auth_password(ssh_session session, const char *user,
+                             const char *password, void *userdata)
+{
+    ssh_client_t *client = (ssh_client_t *)userdata;
+
+    (void)session;
+    (void)user;
+    (void)password;
+
+    if (client == NULL) {
+        return SSH_AUTH_DENIED;
+    }
+
+    client->auth_attempts++;
+    client->ssh_authenticated = 1;
+    return SSH_AUTH_SUCCESS;
+}
+
+static hybbx_result_t ssh_plugin_stop(void);
+
+static int ssh_channel_pty_request(ssh_session session, ssh_channel channel,
+                                   const char *term, int cols, int rows,
+                                   int py, int px, void *userdata)
+{
+    (void)session;
+    (void)channel;
+    (void)term;
+    (void)cols;
+    (void)rows;
+    (void)py;
+    (void)px;
+    (void)userdata;
+    return SSH_OK;
+}
+
+static int ssh_channel_shell_request(ssh_session session, ssh_channel channel,
+                                     void *userdata)
+{
+    ssh_client_t *client = (ssh_client_t *)userdata;
+
+    (void)session;
+    (void)channel;
+
+    if (client == NULL) {
+        return SSH_ERROR;
+    }
+
+    client->shell_ready = 1;
+    return SSH_OK;
+}
+
+static ssh_channel ssh_channel_open(ssh_session session, void *userdata)
+{
+    ssh_client_t *client = (ssh_client_t *)userdata;
+
+    (void)session;
+
+    if (client == NULL) {
+        return NULL;
+    }
+
+    client->channel = ssh_channel_new(session);
+    if (client->channel == NULL) {
+        return NULL;
+    }
+
+    memset(&client->channel_cb, 0, sizeof(client->channel_cb));
+    client->channel_cb.userdata = client;
+    client->channel_cb.channel_pty_request_function = ssh_channel_pty_request;
+    client->channel_cb.channel_shell_request_function = ssh_channel_shell_request;
+    ssh_callbacks_init(&client->channel_cb);
+    ssh_set_channel_callbacks(client->channel, &client->channel_cb);
+
+    return client->channel;
+}
+
+static hybbx_result_t ssh_plugin_write(hybbx_session_t *session,
+                                const char *data, size_t len)
+{
+    ssh_client_t *client;
+    size_t i;
+    int rc;
+
+    if (session == NULL || data == NULL) {
+        return HYBBX_ERR_INVALID;
+    }
+
+    client = (ssh_client_t *)session->transport_data;
+    if (client == NULL || client->channel == NULL) {
+        return HYBBX_ERR_INVALID;
+    }
+
+    for (i = 0; i < len; i++) {
+        char out[2];
+        size_t out_len = 1;
+
+        out[0] = data[i];
+        if (data[i] == '\n' && (i == 0 || data[i - 1] != '\r')) {
+            out[0] = '\r';
+            out[1] = '\n';
+            out_len = 2;
+        }
+
+        rc = ssh_channel_write(client->channel, out, out_len);
+        if (rc < 0) {
+            return HYBBX_ERR_IO;
+        }
+    }
+
+    return HYBBX_OK;
+}
+
+static void ssh_send_busy(ssh_channel channel)
+{
+    static const char msg[] = "All nodes in use. Try later.\r\n";
+
+    if (channel == NULL) {
+        return;
+    }
+
+    (void)ssh_channel_write(channel, msg, sizeof(msg) - 1u);
+}
+
+static int ssh_wait_auth_and_shell(ssh_client_t *client)
+{
+    int ticks = 0;
+
+    while (g_ssh_running) {
+        if (client->ssh_authenticated && client->channel != NULL &&
+            client->shell_ready) {
+            return 0;
+        }
+
+        if (client->auth_attempts >= 5 || ticks >= 300) {
+            return -1;
+        }
+
+        if (ssh_event_dopoll(client->event, 100) == SSH_ERROR) {
+            return -1;
+        }
+        ticks++;
+    }
+
+    return -1;
+}
+
+static void ssh_on_user_data(const uint8_t *data, size_t len, void *ctx)
+{
+    ssh_client_ctx_t *cctx = (ssh_client_ctx_t *)ctx;
+    hybbx_result_t rc;
+
+    if (cctx == NULL || cctx->client == NULL ||
+        cctx->client->hbx_session == NULL || data == NULL || len == 0) {
+        return;
+    }
+
+    rc = hybbx_session_handle_input(cctx->client->hbx_session, data, len);
+    if (rc != HYBBX_OK) {
+        cctx->client->last_rc = rc;
+    }
+}
+
+static int ssh_plugin_service_request(ssh_session session, const char *service,
+                                      void *userdata)
+{
+    (void)session;
+    (void)userdata;
+
+    if (service == NULL) {
+        return SSH_ERROR;
+    }
+
+    if (strcmp(service, "ssh-userauth") == 0 ||
+        strcmp(service, "ssh-connection") == 0) {
+        return SSH_OK;
+    }
+
+    return SSH_ERROR;
+}
+
+static void *ssh_client_thread(void *arg)
+{
+    ssh_client_t *client = (ssh_client_t *)arg;
+    ssh_bind sshbind = NULL;
+    ssh_client_ctx_t cctx;
+    uint8_t buf[SSH_READ_BUF];
+    hybbx_result_t rc;
+    char remote[64];
+
+    if (client == NULL || g_service == NULL) {
+        free(client);
+        return NULL;
+    }
+
+    remote[0] = '\0';
+    (void)hybbx_socket_peer_name(client->fd, remote, sizeof(remote));
+
+    sshbind = ssh_bind_new();
+    if (sshbind == NULL) {
+        goto cleanup;
+    }
+
+    if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY,
+                             g_hostkey_path) != SSH_OK) {
+        hybbx_log_warn("[ssh] host key load failed: %s", g_hostkey_path);
+        goto cleanup;
+    }
+
+    client->session = ssh_new();
+    if (client->session == NULL) {
+        goto cleanup;
+    }
+
+    if (ssh_bind_accept_fd(sshbind, client->session, client->fd) != SSH_OK) {
+        goto cleanup;
+    }
+
+    memset(&client->server_cb, 0, sizeof(client->server_cb));
+    client->server_cb.userdata = client;
+    client->server_cb.auth_password_function = ssh_auth_password;
+    client->server_cb.service_request_function = ssh_plugin_service_request;
+    client->server_cb.channel_open_request_session_function = ssh_channel_open;
+    ssh_callbacks_init(&client->server_cb);
+    ssh_set_server_callbacks(client->session, &client->server_cb);
+    ssh_set_auth_methods(client->session, SSH_AUTH_METHOD_PASSWORD);
+
+    if (ssh_server_init_kex(client->session) != SSH_OK) {
+        goto cleanup;
+    }
+
+    if (ssh_handle_key_exchange(client->session) != SSH_OK) {
+        goto cleanup;
+    }
+
+    client->event = ssh_event_new();
+    if (client->event == NULL) {
+        goto cleanup;
+    }
+
+    if (ssh_event_add_session(client->event, client->session) != SSH_OK) {
+        goto cleanup;
+    }
+
+    if (ssh_wait_auth_and_shell(client) != 0) {
+        goto cleanup;
+    }
+
+    rc = hybbx_session_open(g_service, &hybbx_plugin_ssh, client,
+                            &client->hbx_session);
+    if (rc != HYBBX_OK || client->hbx_session == NULL) {
+        if (rc == HYBBX_ERR_BUSY) {
+            ssh_send_busy(client->channel);
+        }
+        goto cleanup;
+    }
+
+    if (remote[0] != '\0') {
+        (void)hybbx_session_set_remote(client->hbx_session, remote);
+    }
+
+    /*
+     * Telnet clients echo locally when the server sends WONT ECHO; SSH PTY
+     * clients do not. Mirror telnet UX by enabling HyBBX input echo unless
+     * [traffic] input_echo=yes already turned it on.
+     */
+    {
+        const hybbx_traffic_config_t *traffic = hybbx_traffic_config_get();
+
+        if (traffic == NULL || !traffic->input_echo) {
+            (void)hybbx_session_set_input_echo(client->hbx_session, 1);
+        }
+    }
+
+    cctx.client = client;
+    client->last_rc = HYBBX_OK;
+
+    while (g_ssh_running && ssh_channel_is_open(client->channel)) {
+        int n;
+        int ev;
+
+        ev = ssh_event_dopoll(client->event, SSH_CLIENT_POLL_MS);
+        if (ev == SSH_ERROR) {
+            break;
+        }
+
+        if (ev == 0) {
+            rc = hybbx_session_tick(client->hbx_session);
+            if (rc == HYBBX_SESSION_END) {
+                client->last_rc = HYBBX_SESSION_END;
+                break;
+            }
+        }
+
+        while ((n = ssh_channel_read(client->channel, buf, sizeof(buf), 0)) > 0) {
+            ssh_on_user_data((const uint8_t *)buf, (size_t)n, &cctx);
+            if (client->last_rc == HYBBX_SESSION_END) {
+                break;
+            }
+        }
+        if (client->last_rc == HYBBX_SESSION_END) {
+            break;
+        }
+        if (n < 0 && !ssh_channel_is_open(client->channel)) {
+            break;
+        }
+
+        rc = hybbx_session_tick(client->hbx_session);
+        if (rc == HYBBX_SESSION_END) {
+            client->last_rc = HYBBX_SESSION_END;
+            break;
+        }
+    }
+
+cleanup:
+    if (client->hbx_session != NULL) {
+        hybbx_session_close(client->hbx_session);
+        client->hbx_session = NULL;
+    }
+
+    if (client->channel != NULL) {
+        if (ssh_channel_is_open(client->channel)) {
+            ssh_channel_send_eof(client->channel);
+            ssh_channel_close(client->channel);
+        }
+        ssh_channel_free(client->channel);
+        client->channel = NULL;
+    }
+
+    if (client->event != NULL) {
+        ssh_event_free(client->event);
+        client->event = NULL;
+    }
+
+    if (client->session != NULL) {
+        ssh_disconnect(client->session);
+        ssh_free(client->session);
+        client->session = NULL;
+    }
+
+    if (sshbind != NULL) {
+        ssh_bind_free(sshbind);
+        sshbind = NULL;
+    }
+
+    if (client->fd >= 0) {
+        client->fd = -1;
+    }
+
+    free(client);
+    return NULL;
+}
+
+static void accept_client(int client_fd)
+{
+    ssh_client_t *client;
+    pthread_t thread;
+    pthread_attr_t attr;
+
+    client = calloc(1, sizeof(*client));
+    if (client == NULL) {
+        close(client_fd);
+        return;
+    }
+
+    client->fd = client_fd;
+
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+    if (pthread_create(&thread, &attr, ssh_client_thread, client) != 0) {
+        close(client_fd);
+        free(client);
+    }
+
+    pthread_attr_destroy(&attr);
+}
+
+static void *ssh_accept_thread(void *arg)
+{
+    (void)arg;
+
+    while (g_ssh_running) {
+        struct pollfd fds[2];
+        nfds_t nfds = 0;
+        int i;
+        int ready;
+
+        memset(fds, 0, sizeof(fds));
+
+        if (g_listen_v4 >= 0) {
+            fds[nfds].fd = g_listen_v4;
+            fds[nfds].events = POLLIN;
+            nfds++;
+        }
+
+        if (g_listen_v6 >= 0) {
+            fds[nfds].fd = g_listen_v6;
+            fds[nfds].events = POLLIN;
+            nfds++;
+        }
+
+        if (nfds == 0) {
+            break;
+        }
+
+        ready = poll(fds, nfds, 500);
+        if (ready < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+            break;
+        }
+
+        if (ready == 0) {
+            continue;
+        }
+
+        for (i = 0; i < (int)nfds; i++) {
+            if (fds[i].revents & POLLIN) {
+                int client_fd = accept(fds[i].fd, NULL, NULL);
+
+                if (client_fd >= 0) {
+                    if (!hybbx_security_ban_accept_fd(client_fd)) {
+                        close(client_fd);
+                        continue;
+                    }
+                    accept_client(client_fd);
+                }
+            }
+        }
+    }
+
+    return NULL;
+}
+
+static hybbx_result_t ssh_plugin_init(hybbx_service_t *service)
+{
+    int rc;
+
+    g_service = service;
+
+    rc = ssh_init();
+    if (rc < 0) {
+        return HYBBX_ERR_IO;
+    }
+
+    return HYBBX_OK;
+}
+
+static void ssh_plugin_shutdown(void)
+{
+    ssh_plugin_stop();
+    ssh_finalize();
+}
+
+static hybbx_result_t ssh_plugin_start(const char *config)
+{
+    char keys_resolved[HYBBX_PATH_MAX];
+    hybbx_result_t rc;
+
+    if (g_ssh_running) {
+        return HYBBX_ERR_BUSY;
+    }
+
+    rc = hybbx_ssh_config_parse(config, &g_config);
+    if (rc != HYBBX_OK) {
+        return rc;
+    }
+
+    if (hybbx_path_resolve(keys_resolved, sizeof(keys_resolved),
+                           g_config.hostkey_dir) != HYBBX_OK) {
+        hybbx_strlcpy(keys_resolved, g_config.hostkey_dir,
+                      sizeof(keys_resolved));
+    }
+
+    rc = hybbx_ssh_keys_ensure(keys_resolved, g_hostkey_path,
+                               sizeof(g_hostkey_path));
+    if (rc != HYBBX_OK) {
+        return rc;
+    }
+
+    g_listen_v4 = -1;
+    g_listen_v6 = -1;
+
+    if (g_config.ipv4) {
+        g_listen_v4 = create_listen_socket(AF_INET, g_config.bind_v4,
+                                           g_config.port);
+        if (g_listen_v4 < 0) {
+            hybbx_socket_log_bind_failure("ssh", g_config.bind_v4,
+                                          g_config.port);
+            return HYBBX_ERR_IO;
+        }
+    }
+
+    if (g_config.ipv6) {
+        g_listen_v6 = create_listen_socket(AF_INET6, g_config.bind_v6,
+                                           g_config.port);
+        if (g_listen_v6 < 0) {
+            hybbx_log_warn("[ssh] IPv6 bind [%s]:%u skipped (%s)",
+                           g_config.bind_v6, g_config.port, strerror(errno));
+        }
+    }
+
+    if (g_listen_v4 < 0 && g_listen_v6 < 0) {
+        return HYBBX_ERR_IO;
+    }
+
+    g_ssh_running = 1;
+
+    if (pthread_create(&g_accept_thread, NULL, ssh_accept_thread, NULL) != 0) {
+        g_ssh_running = 0;
+        if (g_listen_v4 >= 0) {
+            close(g_listen_v4);
+            g_listen_v4 = -1;
+        }
+        if (g_listen_v6 >= 0) {
+            close(g_listen_v6);
+            g_listen_v6 = -1;
+        }
+        return HYBBX_ERR_IO;
+    }
+
+    {
+        char msg[256];
+        size_t pos = 0;
+
+        pos += (size_t)snprintf(msg + pos, sizeof(msg) - pos, "[ssh] listening");
+        if (g_listen_v4 >= 0) {
+            pos += (size_t)snprintf(msg + pos, sizeof(msg) - pos, " IPv4 %s:%u",
+                                    g_config.bind_v4, g_config.port);
+        }
+        if (g_listen_v6 >= 0) {
+            pos += (size_t)snprintf(msg + pos, sizeof(msg) - pos, " IPv6 [%s]:%u",
+                                    g_config.bind_v6, g_config.port);
+        }
+        pos += (size_t)snprintf(msg + pos, sizeof(msg) - pos, " (libssh)");
+        hybbx_log_info("%s", msg);
+    }
+
+    return HYBBX_OK;
+}
+
+static hybbx_result_t ssh_plugin_stop(void)
+{
+    if (!g_ssh_running) {
+        return HYBBX_OK;
+    }
+
+    g_ssh_running = 0;
+
+    if (g_listen_v4 >= 0) {
+        shutdown(g_listen_v4, SHUT_RDWR);
+        close(g_listen_v4);
+        g_listen_v4 = -1;
+    }
+
+    if (g_listen_v6 >= 0) {
+        shutdown(g_listen_v6, SHUT_RDWR);
+        close(g_listen_v6);
+        g_listen_v6 = -1;
+    }
+
+    pthread_join(g_accept_thread, NULL);
+    hybbx_log_info("[ssh] stop");
+    return HYBBX_OK;
+}
+
+const hybbx_transport_plugin_t hybbx_plugin_ssh = {
+    .name = "ssh",
+    .kind = HYBBX_TRANSPORT_SSH,
+    .version = 1,
+    .init = ssh_plugin_init,
+    .shutdown = ssh_plugin_shutdown,
+    .start = ssh_plugin_start,
+    .stop = ssh_plugin_stop,
+    .write = ssh_plugin_write,
+};