/* sshdump.c
 * sshdump is extcap tool used to capture data using a remote ssh host
 *
 * Copyright 2015, Dario Lombardo
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"
#define WS_LOG_DOMAIN "sshdump"

#include <extcap/extcap-base.h>
#include <extcap/ssh-base.h>
#include <wsutil/interface.h>
#include <wsutil/file_util.h>
#include <wsutil/strtoi.h>
#include <wsutil/filesystem.h>
#include <wsutil/privileges.h>
#include <wsutil/please_report_bug.h>
#include <wsutil/wslog.h>
#include <app/application_flavor.h>

#include <errno.h>
#include <string.h>
#include <fcntl.h>

#include <cli_main.h>

static char* sshdump_extcap_interface;
#define DEFAULT_SSHDUMP_EXTCAP_INTERFACE "sshdump"

#define SSHDUMP_VERSION_MAJOR "1"
#define SSHDUMP_VERSION_MINOR "2"
#define SSHDUMP_VERSION_RELEASE "0"

enum {
	EXTCAP_BASE_OPTIONS_ENUM,
	OPT_HELP,
	OPT_VERSION,
	SSH_BASE_PACKET_OPTIONS_ENUM,
	OPT_REMOTE_CAPTURE_COMMAND_SELECT,
	OPT_REMOTE_CAPTURE_COMMAND,
	OPT_REMOTE_COUNT,
	OPT_REMOTE_SUDO,	// Deprecated
	OPT_REMOTE_PRIV,
	OPT_REMOTE_PRIV_USER,
	OPT_REMOTE_NOPROM
};

static const struct ws_option longopts[] = {
	EXTCAP_BASE_OPTIONS,
	{ "help", ws_no_argument, NULL, OPT_HELP},
	{ "version", ws_no_argument, NULL, OPT_VERSION},
	SSH_BASE_PACKET_OPTIONS,
	{ "remote-capture-command-select", ws_required_argument, NULL, OPT_REMOTE_CAPTURE_COMMAND_SELECT},
	{ "remote-capture-command", ws_required_argument, NULL, OPT_REMOTE_CAPTURE_COMMAND},
	{ "remote-sudo", ws_no_argument, NULL, OPT_REMOTE_SUDO },	// Deprecated
	{ "remote-priv", ws_required_argument, NULL, OPT_REMOTE_PRIV },
	{ "remote-priv-user", ws_required_argument, NULL, OPT_REMOTE_PRIV_USER },
	{ "remote-noprom", ws_no_argument, NULL, OPT_REMOTE_NOPROM },
	{ 0, 0, 0, 0}
};

static char* interfaces_list_to_filter(GSList* if_list, unsigned int remote_port);

static char* local_interfaces_to_filter(const uint16_t remote_port)
{
	GSList* interfaces = local_interfaces_to_list();
	char* filter = interfaces_list_to_filter(interfaces, remote_port);
	g_slist_free_full(interfaces, g_free);
	return filter;
}

static ssh_channel run_ssh_command(ssh_session sshs, const char* capture_command_select,
		const char* capture_command, const char* privilege, bool noprom,
		const char* iface, const char* cfilter, const uint32_t count)
{
	char* cmdline = NULL;
	ssh_channel channel;
	char** ifaces_array = NULL;
	int ifaces_array_num = 0;
	GString *ifaces_string;
	char *ifaces = NULL;
	char* quoted_iface = NULL;
	char* quoted_filter = NULL;
	char* count_str = NULL;
	unsigned int remote_port = 22;

	channel = ssh_channel_new(sshs);
	if (!channel) {
		ws_warning("Can't create channel");
		return NULL;
	}

	if (ssh_channel_open_session(channel) != SSH_OK) {
		ws_warning("Can't open session");
		ssh_channel_free(channel);
		return NULL;
	}

	ssh_options_get_port(sshs, &remote_port);

	if (capture_command_select == NULL || !g_strcmp0(capture_command_select, "other")) {
		if (capture_command && *capture_command) {
			cmdline = g_strdup(capture_command);
			ws_debug("Remote capture command has disabled other options");
		} else {
			capture_command_select = "tcpdump";
		}
	}

	/* escape parameters to go save with the shell */
	if (!g_strcmp0(capture_command_select, "tcpdump")) {
		quoted_iface = iface ? g_shell_quote(iface) : NULL;
		quoted_filter = g_shell_quote(cfilter ? cfilter : "");
		if (count > 0)
			count_str = ws_strdup_printf("-c %u", count);

		cmdline = ws_strdup_printf("%s tcpdump -U %s%s %s -w - %s %s",
			privilege,
			quoted_iface ? "-i " : "",
			quoted_iface ? quoted_iface : "",
			noprom ? "-p" : "",
			count_str ? count_str : "",
			quoted_filter);
	} else if (!g_strcmp0(capture_command_select, "dumpcap")) {
		if (iface) {
			ifaces_array = g_strsplit(iface, " ", -1);
			ifaces_string = g_string_new(NULL);
			while (ifaces_array[ifaces_array_num])
			{
				quoted_iface = g_shell_quote(ifaces_array[ifaces_array_num]);
				g_string_append_printf(ifaces_string, "-i %s ", quoted_iface);
				ifaces_array_num++;
			}
			ifaces = g_string_free(ifaces_string, FALSE);
		}
		quoted_filter = g_shell_quote(cfilter ? cfilter : "");
		if (count > 0)
			count_str = ws_strdup_printf("-c %u", count);

		cmdline = ws_strdup_printf("%s dumpcap %s %s -w - %s -f %s",
			privilege,
			noprom ? "-p" : "",
			ifaces ? ifaces : "",
			count_str ? count_str : "",
			quoted_filter);

		g_free(ifaces);
		g_strfreev(ifaces_array);
	}

	ws_debug("Running: %s", cmdline);
	if (ssh_channel_request_exec(channel, cmdline) != SSH_OK) {
		ws_warning("Can't request exec");
		ssh_channel_close(channel);
		ssh_channel_free(channel);
		channel = NULL;
	}

	g_free(quoted_iface);
	g_free(quoted_filter);
	g_free(cmdline);
	g_free(count_str);

	return channel;
}

static int ssh_open_remote_connection(const ssh_params_t* params, const char* iface, const char* cfilter,
	const char* capture_command_select, const char* capture_command, const char* privilege,
	bool noprom, const uint32_t count, const char* fifo)
{
	ssh_session sshs = NULL;
	ssh_channel channel = NULL;
	FILE* fp = stdout;
	int ret = EXIT_FAILURE;
	char* err_info = NULL;

	if (g_strcmp0(fifo, "-")) {
		/* Open or create the output file */
		fp = fopen(fifo, "wb");
		if (fp == NULL) {
			ws_warning("Error creating output file: %s (%s)", fifo, g_strerror(errno));
			return EXIT_FAILURE;
		}
	}

	sshs = create_ssh_connection(params, &err_info);

	if (!sshs) {
		ws_warning("Error creating connection.");
		goto cleanup;
	}

	channel = run_ssh_command(sshs, capture_command_select, capture_command, privilege, noprom, iface, cfilter, count);

	if (!channel) {
		ws_warning("Can't run ssh command.");
		goto cleanup;
	}

	/* read from channel and write into fp */
	if (ssh_async_loop_read(sshs, channel, fp) != EXIT_SUCCESS) {
		ws_warning("Error in read loop.");
		ret = EXIT_FAILURE;
		goto cleanup;
	}

	ret = EXIT_SUCCESS;
cleanup:
	if (err_info)
		ws_warning("%s", err_info);
	g_free(err_info);

	/* clean up and exit */
	ssh_cleanup(&sshs, &channel);

	if (g_strcmp0(fifo, "-"))
		fclose(fp);
	return ret;
}

static char* interfaces_list_to_filter(GSList* interfaces, unsigned int remote_port)
{
	GString* filter = g_string_new(NULL);
	GSList* cur;

	// If no port is given, assume the default one. This might not be
	// correct if the port is looked up from the ssh config file, but it is
	// better than nothing.
	if (remote_port == 0) {
		remote_port = 22;
	}

	if (!interfaces) {
		g_string_append_printf(filter, "not port %u", remote_port);
	} else {
		g_string_append_printf(filter, "not ((host %s", (char*)interfaces->data);
		cur = g_slist_next(interfaces);
		while (cur) {
			g_string_append_printf(filter, " or host %s", (char*)cur->data);
			cur = g_slist_next(cur);
		}
		g_string_append_printf(filter, ") and port %u)", remote_port);
	}
	return g_string_free(filter, FALSE);
}

static int list_config(char *interface, unsigned int remote_port)
{
	unsigned inc = 0;
	char* ipfilter;

	if (!interface) {
		ws_warning("ERROR: No interface specified.");
		return EXIT_FAILURE;
	}

	if (g_strcmp0(interface, sshdump_extcap_interface)) {
		ws_warning("ERROR: interface must be %s", sshdump_extcap_interface);
		return EXIT_FAILURE;
	}

	ipfilter = local_interfaces_to_filter(remote_port);

	ssh_base_list_config(&inc);

	printf("arg {number=%u}{call=--remote-interface}{display=Remote interface}"
		"{type=string}{tooltip=The remote network interface used for capture"
		"}{group=Capture}\n", inc++);
	printf("arg {number=%u}{call=--remote-capture-command-select}{display=Remote capture command selection}"
		"{type=radio}{tooltip=The remote capture command to build a command line for}{group=Capture}\n", inc);
	printf("value {arg=%u}{value=dumpcap}{display=dumpcap}\n", inc);
	printf("value {arg=%u}{value=tcpdump}{display=tcpdump}{default=true}\n", inc);
	printf("value {arg=%u}{value=other}{display=Other:}\n", inc++);
	printf("arg {number=%u}{call=--remote-capture-command}{display=Remote capture command}"
		"{type=string}{tooltip=The remote command used to capture}{group=Capture}\n", inc++);
	// Deprecated
	//printf("arg {number=%u}{call=--remote-sudo}{display=Use sudo on the remote machine}"
	// 	"{type=boolflag}{tooltip=Prepend the capture command with sudo on the remote machine}"
	// 	"{group=Capture}\n", inc++);
	printf("arg {number=%u}{call=--remote-priv}{display=Gain capture privilege on the remote machine}"
		"{type=radio}{tooltip=Optionally prepend the capture command with sudo or doas on the remote machine}"
		"{group=Capture}\n", inc);
	printf("value {arg=%u}{value=none}{display=none}{default=true}\n", inc);
	printf("value {arg=%u}{value=sudo}{display=sudo}\n", inc);
	printf("value {arg=%u}{value=doas -n}{display=doas}\n", inc++);
	printf("arg {number=%u}{call=--remote-priv-user}{display=Privileged user name for sudo or doas}"
		"{type=string}{tooltip=User name of privileged user to execute the capture command on the remote machine}"
		"{group=Capture}\n", inc++);
	printf("arg {number=%u}{call=--remote-noprom}{display=No promiscuous mode}"
		"{type=boolflag}{tooltip=Don't use promiscuous mode on the remote machine}{group=Capture}"
		"\n", inc++);
	printf("arg {number=%u}{call=--remote-filter}{display=Remote capture filter}{type=string}"
		"{tooltip=The remote capture filter}", inc++);
	if (ipfilter)
		printf("{default=%s}", ipfilter);
	printf("{group=Capture}\n");
	printf("arg {number=%u}{call=--remote-count}{display=Packets to capture}"
		"{type=unsigned}{default=0}{tooltip=The number of remote packets to capture. (Default: inf)}"
		"{group=Capture}\n", inc++);

	extcap_config_debug(&inc);

	g_free(ipfilter);

	return EXIT_SUCCESS;
}

static char* concat_filters(const char* extcap_filter, const char* remote_filter)
{
	if (!extcap_filter && remote_filter)
		return g_strdup(remote_filter);

	if (!remote_filter && extcap_filter)
		return g_strdup(extcap_filter);

	if (!remote_filter && !extcap_filter)
		return NULL;

	return ws_strdup_printf("(%s) and (%s)", extcap_filter, remote_filter);
}

int main(int argc, char *argv[])
{
	char* err_msg;
	int result;
	int option_idx = 0;
	ssh_params_t* ssh_params = ssh_params_new();
	char* remote_interface = NULL;
	char* remote_capture_command_select = NULL;
	char* remote_capture_command = NULL;
	char* remote_filter = NULL;
	uint32_t count = 0;
	int ret = EXIT_FAILURE;
	extcap_parameters* extcap_conf = g_new0(extcap_parameters, 1);
	char* help_url;
	char* help_header = NULL;
	char* priv = NULL;
	char* priv_user = NULL;
	bool noprom = false;
	char* interface_description = g_strdup("SSH remote capture");

	/* Set the program name. */
	g_set_prgname("sshdump");

	/* Initialize log handler early so we can have proper logging during startup. */
	extcap_log_init();

	sshdump_extcap_interface = g_path_get_basename(argv[0]);
	if (g_str_has_suffix(sshdump_extcap_interface, ".exe")) {
		sshdump_extcap_interface[strlen(sshdump_extcap_interface) - 4] = '\0';
	}

	/*
	 * Get credential information for later use.
	 */
	init_process_policies();

	/*
	 * Attempt to get the pathname of the directory containing the
	 * executable file.
	 */
	err_msg = configuration_init(argv[0], "wireshark");
	if (err_msg != NULL) {
		ws_warning("Can't get pathname of directory containing the extcap program: %s.",
			err_msg);
		g_free(err_msg);
	}

	help_url = data_file_url("sshdump.html", application_configuration_environment_prefix());
	extcap_base_set_util_info(extcap_conf, argv[0], SSHDUMP_VERSION_MAJOR, SSHDUMP_VERSION_MINOR,
		SSHDUMP_VERSION_RELEASE, help_url);
	g_free(help_url);
	add_libssh_info(extcap_conf);
	if (g_strcmp0(sshdump_extcap_interface, DEFAULT_SSHDUMP_EXTCAP_INTERFACE)) {
		char* temp = interface_description;
		interface_description = ws_strdup_printf("%s, custom version", interface_description);
		g_free(temp);
	}
	extcap_base_register_interface(extcap_conf, sshdump_extcap_interface, interface_description, 147, "Remote capture dependent DLT");
	g_free(interface_description);

	help_header = ws_strdup_printf(
		" %s --extcap-interfaces\n"
		" %s --extcap-interface=%s --extcap-dlts\n"
		" %s --extcap-interface=%s --extcap-config\n"
		" %s --extcap-interface=%s --remote-host myhost --remote-port 22222 "
		"--remote-username myuser --remote-interface eth2 --remote-capture-command 'tcpdump -U -i eth0 -w -' "
		"--fifo=FILENAME --capture\n", argv[0], argv[0], sshdump_extcap_interface, argv[0],
		sshdump_extcap_interface, argv[0], sshdump_extcap_interface);
	extcap_help_add_header(extcap_conf, help_header);
	g_free(help_header);
	extcap_help_add_option(extcap_conf, "--help", "print this help");
	extcap_help_add_option(extcap_conf, "--version", "print the version");
	ssh_base_add_help_options(extcap_conf);
	extcap_help_add_option(extcap_conf, "--remote-interface <iface>", "the remote capture interface");
	extcap_help_add_option(extcap_conf, "--remote-capture-command-select <selection>", "dumpcap, tcpdump or other remote capture command");
	extcap_help_add_option(extcap_conf, "--remote-capture-command <capture command>", "the remote capture command");
	//extcap_help_add_option(extcap_conf, "--remote-sudo", "use sudo on the remote machine to capture");	// Deprecated
	extcap_help_add_option(extcap_conf, "--remote-priv <selection>", "none, sudo or doas");
	extcap_help_add_option(extcap_conf, "--remote-priv-user <username>", "privileged user name");
	extcap_help_add_option(extcap_conf, "--remote-noprom", "don't use promiscuous mode on the remote machine");
	extcap_help_add_option(extcap_conf, "--remote-filter <filter>", "a filter for remote capture (default: don't listen on local interfaces IPs)");
	extcap_help_add_option(extcap_conf, "--remote-count <count>", "the number of packets to capture");

	ws_opterr = 0;
	ws_optind = 0;

	if (argc == 1) {
		extcap_help_print(extcap_conf);
		goto end;
	}

	// Do this before reading the options, which sets up the control pipe
	if (!ssh_base_setup_graceful_shutdown(extcap_conf)) {
		ret = EXIT_FAILURE;
		goto end;
	}

	while ((result = ws_getopt_long(argc, argv, ":", longopts, &option_idx)) != -1) {

		switch (result) {

		case OPT_HELP:
			extcap_help_print(extcap_conf);
			ret = EXIT_SUCCESS;
			goto end;

		case OPT_VERSION:
			extcap_version_print(extcap_conf);
			ret = EXIT_SUCCESS;
			goto end;

		case OPT_REMOTE_HOST:
			g_free(ssh_params->host);
			ssh_params->host = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_PORT:
			if (!ws_strtou16(ws_optarg, NULL, &ssh_params->port) || ssh_params->port == 0) {
				ws_warning("Invalid port: %s", ws_optarg);
				goto end;
			}
			break;

		case OPT_REMOTE_USERNAME:
			g_free(ssh_params->username);
			ssh_params->username = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_PASSWORD:
			g_free(ssh_params->password);
			ssh_params->password = g_strdup(ws_optarg);
			memset(ws_optarg, 'X', strlen(ws_optarg));
			break;

		case OPT_SSHKEY:
			g_free(ssh_params->sshkey_path);
			ssh_params->sshkey_path = g_strdup(ws_optarg);
			break;

		case OPT_SSHKEY_PASSPHRASE:
			g_free(ssh_params->sshkey_passphrase);
			ssh_params->sshkey_passphrase = g_strdup(ws_optarg);
			memset(ws_optarg, 'X', strlen(ws_optarg));
			break;

		case OPT_PROXYCOMMAND:
			g_free(ssh_params->proxycommand);
			ssh_params->proxycommand = g_strdup(ws_optarg);
			break;

		case OPT_SSH_SHA1:
			ssh_params->ssh_sha1 = true;
			break;

		case OPT_UPDATE_KNOWN_HOSTS:
			ssh_params->update_known_hosts = true;
			break;

		case OPT_REMOTE_INTERFACE:
			g_free(remote_interface);
			remote_interface = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_CAPTURE_COMMAND_SELECT:
			g_free(remote_capture_command_select);
			remote_capture_command_select = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_CAPTURE_COMMAND:
			g_free(remote_capture_command);
			remote_capture_command = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_SUDO:
			// Deprecated
			g_free(priv);
			priv = g_strdup("sudo");
			break;

		case OPT_REMOTE_PRIV:
			g_free(priv);
			priv = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_PRIV_USER:
			g_free(priv_user);
			priv_user = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_FILTER:
			g_free(remote_filter);
			remote_filter = g_strdup(ws_optarg);
			break;

		case OPT_REMOTE_COUNT:
			if (!ws_strtou32(ws_optarg, NULL, &count)) {
				ws_warning("Invalid value for count: %s", ws_optarg);
				goto end;
			}
			break;

		case OPT_REMOTE_NOPROM:
			noprom = true;
			break;

		case ':':
			/* missing option argument */
			ws_warning("Option '%s' requires an argument", argv[ws_optind - 1]);
			break;

		default:
			if (!extcap_base_parse_options(extcap_conf, result - EXTCAP_OPT_LIST_INTERFACES, ws_optarg)) {
				ws_warning("Invalid option: %s", argv[ws_optind - 1]);
				goto end;
			}
		}
	}

	extcap_cmdline_debug(argv, argc);

	if (extcap_base_handle_interface(extcap_conf)) {
		ret = EXIT_SUCCESS;
		goto end;
	}

	if (extcap_conf->show_config) {
		ret = list_config(extcap_conf->interface, ssh_params->port);
		goto end;
	}

	err_msg = ws_init_sockets();
	if (err_msg != NULL) {
		ws_warning("ERROR: %s", err_msg);
		g_free(err_msg);
		ws_warning("%s", please_report_bug());
		goto end;
	}

	if (extcap_conf->capture) {
		char* filter;
		char* privilege;

		if (!ssh_params->host) {
			ws_warning("Missing parameter: --remote-host");
			goto end;
		}

		if ((priv) && g_strcmp0(priv, "none") && strlen(g_strstrip(priv))) {
			if ((priv_user) && strlen(g_strstrip(priv_user)))
				/* Both sudo and doas use the same command line option */
				privilege = g_strconcat(priv, " -u ", priv_user, NULL);
			else
				privilege = g_strdup(priv);
		} else {
			privilege = g_strdup("");
		}

		// This may result in the use of a different port number than was given in
		// the default filter string, as presented in the config dialog. The default
		// given is always using the default SSH port since there's no remote SSH port
		// given on the command line to get the extcap arguments.
		// However the remote SSH port used here is the one given on the command line
		// when the capture us started, which is the intended one.
		// And this is only happening when no remote filter is specified on the command
		// line to start the capture.
		if (remote_filter == NULL)
			remote_filter = local_interfaces_to_filter(ssh_params->port);
		filter = concat_filters(extcap_conf->capture_filter, remote_filter);
		ssh_params_set_log_level(ssh_params, extcap_conf->debug);
		ret = ssh_open_remote_connection(ssh_params, remote_interface,
			filter, remote_capture_command_select, remote_capture_command,
			privilege, noprom, count, extcap_conf->fifo);
		g_free(filter);
		g_free(privilege);
	} else {
		ws_debug("You should not come here... maybe some parameter missing?");
		ret = EXIT_FAILURE;
	}

end:
	/* clean up stuff */
	ssh_params_free(ssh_params);
	g_free(remote_capture_command_select);
	g_free(remote_capture_command);
	g_free(remote_interface);
	g_free(remote_filter);
	g_free(priv);
	g_free(priv_user);
	extcap_base_cleanup(&extcap_conf);
	return ret;
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */
