/*
 * Copyright (C) 2014-2020 Firejail Authors
 *
 * This file is part of firejail project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include "firejail.h"
#include "../include/ldd_utils.h"
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <dirent.h>
#include <glob.h>
#define MAXBUF 4096

extern void fslib_install_stdc(void);
extern void fslib_install_system(void);

static int lib_cnt = 0;
static int dir_cnt = 0;

char *find_in_path(const char *program) {
	EUID_ASSERT();
	if (arg_debug)
		printf("Searching $PATH for %s\n", program);

	char self[MAXBUF];
	ssize_t len = readlink("/proc/self/exe", self, MAXBUF - 1);
	if (len < 0)
		errExit("readlink");
	self[len] = '\0';

	char *path = getenv("PATH");
	if (!path)
		return NULL;
	char *dup = strdup(path);
	if (!dup)
		errExit("strdup");
	char *tok = strtok(dup, ":");
	while (tok) {
		char *fname;
		if (asprintf(&fname, "%s/%s", tok, program) == -1)
			errExit("asprintf");

		if (arg_debug)
			printf("trying #%s#\n", fname);
		struct stat s;
		if (stat(fname, &s) == 0) {
			// but skip links created by firecfg
			char *rp = realpath(fname, NULL);
			if (!rp)
				errExit("realpath");
			if (strcmp(self, rp) != 0) {
				free(rp);
				free(dup);
				return fname;
			}
			free(rp);
		}
		free(fname);
		tok = strtok(NULL, ":");
	}

	free(dup);
	return NULL;
}

static void report_duplication(const char *full_path) {
	char *fname = strrchr(full_path, '/');
	if (fname && *(++fname) != '\0') {
		// report the file on all bin paths
		int i = 0;
		while (default_lib_paths[i]) {
			char *p;
			if (asprintf(&p, "%s/%s", default_lib_paths[i], fname) == -1)
				errExit("asprintf");
			fs_logger2("clone", p);
			free(p);
			i++;
		}
	}
}

static char *build_dest_dir(const char *full_path) {
	assert(full_path);
	if (strstr(full_path, "/x86_64-linux-gnu/"))
		return RUN_LIB_DIR "/x86_64-linux-gnu";
	return RUN_LIB_DIR;
}

// copy fname in private_run_dir
void fslib_duplicate(const char *full_path) {
	assert(full_path);

	struct stat s;
	if (stat(full_path, &s) != 0 || s.st_uid != 0 || access(full_path, R_OK))
		return;

	char *dest_dir = build_dest_dir(full_path);

	// don't copy it if the file is already there
	char *ptr = strrchr(full_path, '/');
	if (!ptr)
		return;
	ptr++;
	if (*ptr == '\0')
		return;

	char *name;
	if (asprintf(&name, "%s/%s", dest_dir, ptr) == -1)
		errExit("asprintf");
	if (stat(name, &s) == 0) {
		free(name);
		return;
	}
	free(name);

	if (arg_debug || arg_debug_private_lib)
		printf("    copying %s to private %s\n", full_path, dest_dir);

	sbox_run(SBOX_ROOT| SBOX_SECCOMP, 4, PATH_FCOPY, "--follow-link", full_path, dest_dir);
	report_duplication(full_path);
	lib_cnt++;
}


// requires full path for lib
// it could be a library or an executable
// lib is not copied, only libraries used by it
void fslib_copy_libs(const char *full_path) {
	assert(full_path);
	if (arg_debug || arg_debug_private_lib)
		printf("    fslib_copy_libs %s\n", full_path);

	// if library/executable does not exist or the user does not have read access to it
	// print a warning and exit the function.
	if (access(full_path, R_OK)) {
		if (arg_debug || arg_debug_private_lib)
			printf("cannot find %s for private-lib, skipping...\n", full_path);
		return;
	}

	// create an empty RUN_LIB_FILE and allow the user to write to it
	unlink(RUN_LIB_FILE);			  // in case is there
	create_empty_file_as_root(RUN_LIB_FILE, 0644);
	if (chown(RUN_LIB_FILE, getuid(), getgid()))
		errExit("chown");

	// run fldd to extract the list of files
	if (arg_debug || arg_debug_private_lib)
		printf("    running fldd %s\n", full_path);
	sbox_run(SBOX_USER | SBOX_SECCOMP | SBOX_CAPS_NONE, 3, PATH_FLDD, full_path, RUN_LIB_FILE);

	// open the list of libraries and install them on by one
	FILE *fp = fopen(RUN_LIB_FILE, "r");
	if (!fp)
		errExit("fopen");

	char buf[MAXBUF];
	while (fgets(buf, MAXBUF, fp)) {
		// remove \n
		char *ptr = strchr(buf, '\n');
		if (ptr)
			*ptr = '\0';
		fslib_duplicate(buf);
	}
	fclose(fp);
	unlink(RUN_LIB_FILE);
}


void fslib_copy_dir(const char *full_path) {
	assert(full_path);
	if (arg_debug || arg_debug_private_lib)
		printf("    fslib_copy_dir %s\n", full_path);

	// do nothing if the directory does not exist or is not owned by root
	struct stat s;
	if (stat(full_path, &s) != 0 || s.st_uid != 0 || !S_ISDIR(s.st_mode) || access(full_path, R_OK))
		return;

	char *dir_name = strrchr(full_path, '/');
	assert(dir_name);
	dir_name++;
	assert(*dir_name != '\0');

	// do nothing if the directory is already there
	char *dest;
	if (asprintf(&dest, "%s/%s", build_dest_dir(full_path), dir_name) == -1)
		errExit("asprintf");
	if (stat(dest, &s) == 0) {
		free(dest);
		return;
	}

	// create new directory and mount the original on top of it
	mkdir_attr(dest, 0755, 0, 0);

	if (mount(full_path, dest, NULL, MS_BIND|MS_REC, NULL) < 0 ||
		mount(NULL, dest, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_NOSUID|MS_NODEV|MS_REC, NULL) < 0)
		errExit("mount bind");
	fs_logger2("clone", full_path);
	fs_logger2("mount", full_path);
	dir_cnt++;
	free(dest);
}

// fname should be a vallid full path at this point
static void load_library(const char *fname) {
	assert(fname);
	assert(*fname == '/');

	// existing file owned by root, read access
	struct stat s;
	if (stat(fname, &s) == 0 && s.st_uid == 0 && !access(fname, R_OK)) {
		// load directories, regular 64 bit libraries, and 64 bit executables
		if (is_dir(fname) || is_lib_64(fname)) {
			if (is_dir(fname))
				fslib_copy_dir(fname);
			else {
				if (strstr(fname, ".so") ||
				    access(fname, X_OK) != 0) // don't duplicate executables, just install the libraries
					fslib_duplicate(fname);

				fslib_copy_libs(fname);
			}
		}
	}
}

static void install_list_entry(const char *lib) {
	assert(lib);

	// filename check
	int len = strlen(lib);
	if (strcspn(lib, "\\&!?\"'<>%^(){}[];,") != (size_t)len ||
	strstr(lib, "..")) {
		fprintf(stderr, "Error: \"%s\" is an invalid library\n", lib);
		exit(1);
	}

	// if this is a full path, use it as is
	if (*lib == '/')
		return load_library(lib);


	// find the library
	int i;
	for (i = 0; default_lib_paths[i]; i++) {
		char *fname = NULL;
		if (asprintf(&fname, "%s/%s", default_lib_paths[i], lib) == -1)
			errExit("asprintf");

#define DO_GLOBBING
#ifdef DO_GLOBBING
		// globbing
		glob_t globbuf;
		int globerr = glob(fname, GLOB_NOCHECK | GLOB_NOSORT | GLOB_PERIOD, NULL, &globbuf);
		if (globerr) {
			fprintf(stderr, "Error: failed to glob private-lib pattern %s\n", fname);
			exit(1);
		}
		size_t j;
		for (j = 0; j < globbuf.gl_pathc; j++) {
			assert(globbuf.gl_pathv[j]);
//printf("glob %s\n", globbuf.gl_pathv[j]);
			// GLOB_NOCHECK - no pattern matched returns the original pattern; try to load it anyway
			load_library(globbuf.gl_pathv[j]);
		}

		globfree(&globbuf);
#else
		load_library(fname);
#endif
		free(fname);
	}

//	fwarning("%s library not found, skipping...\n", lib);
	return;
}


void fslib_install_list(const char *lib_list) {
	assert(lib_list);
	if (arg_debug || arg_debug_private_lib)
		printf("    fslib_install_list  %s\n", lib_list);

	char *dlist = strdup(lib_list);
	if (!dlist)
		errExit("strdup");

	char *ptr = strtok(dlist, ",");
	if (!ptr) {
		fprintf(stderr, "Error: invalid private-lib argument\n");
		exit(1);
	}
	install_list_entry(ptr);

	while ((ptr = strtok(NULL, ",")) != NULL)
		install_list_entry(ptr);
	free(dlist);
	fs_logger_print();
}



static void mount_directories(void) {
	if (arg_debug || arg_debug_private_lib)
		printf("Mount-bind %s on top of /lib /lib64 /usr/lib\n", RUN_LIB_DIR);

	if (is_dir("/lib")) {
		if (mount(RUN_LIB_DIR, "/lib", NULL, MS_BIND|MS_REC, NULL) < 0 ||
			mount(NULL, "/lib", NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NODEV|MS_REC, NULL) < 0)
			errExit("mount bind");
		fs_logger2("tmpfs", "/lib");
		fs_logger("mount /lib");
	}

	if (is_dir("/lib64")) {
		if (mount(RUN_LIB_DIR, "/lib64", NULL, MS_BIND|MS_REC, NULL) < 0 ||
			mount(NULL, "/lib64", NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NODEV|MS_REC, NULL) < 0)
			errExit("mount bind");
		fs_logger2("tmpfs", "/lib64");
		fs_logger("mount /lib64");
	}

	if (is_dir("/usr/lib")) {
		if (mount(RUN_LIB_DIR, "/usr/lib", NULL, MS_BIND|MS_REC, NULL) < 0 ||
			mount(NULL, "/usr/lib", NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NODEV|MS_REC, NULL) < 0)
			errExit("mount bind");
		fs_logger2("tmpfs", "/usr/lib");
		fs_logger("mount /usr/lib");
	}

	// for amd64 only - we'll deal with i386 later
	if (is_dir("/lib32")) {
		if (mount(RUN_RO_DIR, "/lib32", "none", MS_BIND, "mode=400,gid=0") < 0)
			errExit("disable file");
		fs_logger("blacklist-nolog /lib32");
	}
	if (is_dir("/libx32")) {
		if (mount(RUN_RO_DIR, "/libx32", "none", MS_BIND, "mode=400,gid=0") < 0)
			errExit("disable file");
		fs_logger("blacklist-nolog /libx32");
	}
}

void fs_private_lib(void) {
#ifndef __x86_64__
	fwarning("private-lib feature is currently available only on amd64 platforms\n");
	return;
#endif
	char *private_list = cfg.lib_private_keep;
	if (arg_debug || arg_debug_private_lib)
		printf("Starting private-lib processing: program %s, shell %s\n",
			(cfg.original_program_index > 0)? cfg.original_argv[cfg.original_program_index]: "none",
		(arg_shell_none)? "none": cfg.shell);

	// create /run/firejail/mnt/lib directory
	mkdir_attr(RUN_LIB_DIR, 0755, 0, 0);
	selinux_relabel_path(RUN_LIB_DIR, "/usr/lib");

	// install standard C libraries
	if (arg_debug || arg_debug_private_lib)
		printf("Installing standard C library\n");
	fslib_install_stdc();

	// start timetrace
	timetrace_start();

	// bring in firejail executable libraries in case we are redirected here by a firejail symlink from /usr/local/bin/firejail
	if (arg_debug || arg_debug_private_lib)
		printf("Installing Firejail libraries\n");
	fslib_install_list(PATH_FIREJAIL);

	// bring in firejail directory
	fslib_install_list(LIBDIR "/firejail");

	// bring in dhclient libraries
	if (any_dhcp()) {
		if (arg_debug || arg_debug_private_lib)
			printf("Installing dhclient libraries\n");
		fslib_install_list(RUN_MNT_DIR "/dhclient");
	}
	fmessage("Firejail libraries installed in %0.2f ms\n", timetrace_end());

	timetrace_start();

	// copy the libs in the new lib directory for the main exe
	if (cfg.original_program_index > 0) {
		if (arg_debug || arg_debug_private_lib)
			printf("Installing sandboxed program libraries\n");

		if (strchr(cfg.original_argv[cfg.original_program_index], '/'))
			fslib_install_list(cfg.original_argv[cfg.original_program_index]);
		else { // search executable in $PATH
			EUID_USER();
			char *fname = find_in_path(cfg.original_argv[cfg.original_program_index]);
			EUID_ROOT();
			if (fname) {
				fslib_install_list(fname);
				free(fname);
			}
		}
	}

	// for the shell
	if (!arg_shell_none) {
		if (arg_debug || arg_debug_private_lib)
			printf("Installing shell libraries\n");

		fslib_install_list(cfg.shell);
		// a shell is useless without some basic commands
		fslib_install_list("/bin/ls,/bin/cat,/bin/mv,/bin/rm");

	}

	// for the listed libs and directories
	if (private_list && *private_list != '\0') {
		if (arg_debug || arg_debug_private_lib)
			printf("Processing private-lib files\n");
		fslib_install_list(private_list);
	}

	// for private-bin files
	if (arg_private_bin && cfg.bin_private_lib && *cfg.bin_private_lib != '\0') {
		if (arg_debug || arg_debug_private_lib)
			printf("Processing private-bin files\n");
		fslib_install_list(cfg.bin_private_lib);
	}
	fmessage("Program libraries installed in %0.2f ms\n", timetrace_end());

	// install the rest of the system libraries
	if (arg_debug || arg_debug_private_lib)
		printf("Installing system libraries\n");
	fslib_install_system();

	fmessage("Installed %d %s and %d %s\n", lib_cnt, (lib_cnt == 1)? "library": "libraries",
		dir_cnt, (dir_cnt == 1)? "directory": "directories");

	// mount lib filesystem
	mount_directories();
}
