Commit message: fusermount: don't feed "escaped commas" into mount options

The old code permits the following behavior:

$ _FUSE_COMMFD=10000 priv_strace -etrace=mount -s200 fusermount -o 'foobar=\,allow_other' mount
mount("/dev/fuse", ".", "fuse", MS_NOSUID|MS_NODEV, "foobar=\\,allow_other,fd=3,rootmode=40000,user_id=1000,group_id=1000") = -1 EINVAL (Invalid argument)

However, backslashes do not have any special meaning for the kernel here.

As it happens, you can't abuse this because there is no FUSE mount option
that takes a string value that can contain backslashes; but this is very
brittle. Don't interpret "escape characters" in places where they don't
work.
CVE: CVE-2018-10906
CWE: CWE-269
Vulnerability description: In fuse before versions 2.9.8 and 3.x before 3.2.5, fusermount is vulnerable to a restriction bypass when SELinux is active. This allows non-root users to mount a FUSE file system with the 'allow_other' mount option regardless of whether 'user_allow_other' is set in the fuse configuration. An attacker may use this flaw to mount a FUSE file system, accessible by other users, and trick them into accessing files on that file system, possibly causing Denial of Service or other unspecified effects.

Project: libfuse

static int open_fuse_device(char **devp)
{
	int fd = try_open_fuse_device(devp);
	if (fd >= -1)
		return fd;

	fprintf(stderr,
		"%s: fuse device not found, try 'modprobe fuse' first\n",
		progname);

	return -1;
}

Project: libfuse

static int mount_notrunc(const char *source, const char *target,
			 const char *filesystemtype, unsigned long mountflags,
			 const char *data) {
	if (strlen(data) > sysconf(_SC_PAGESIZE) - 1) {
		fprintf(stderr, "%s: mount options too long\n", progname);
		errno = EINVAL;
		return -1;
	}
	return mount(source, target, filesystemtype, mountflags, data);
}

Project: libfuse

static int may_unmount(const char *mnt, int quiet)
{
	struct mntent *entp;
	FILE *fp;
	const char *user = NULL;
	char uidstr[32];
	unsigned uidlen = 0;
	int found;
	const char *mtab = _PATH_MOUNTED;

	user = get_user_name();
	if (user == NULL)
		return -1;

	fp = setmntent(mtab, "r");
	if (fp == NULL) {
		fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
			strerror(errno));
		return -1;
	}

	uidlen = sprintf(uidstr, "%u", getuid());

	found = 0;
	while ((entp = getmntent(fp)) != NULL) {
		if (!found && strcmp(entp->mnt_dir, mnt) == 0 &&
		    (strcmp(entp->mnt_type, "fuse") == 0 ||
		     strcmp(entp->mnt_type, "fuseblk") == 0 ||
		     strncmp(entp->mnt_type, "fuse.", 5) == 0 ||
		     strncmp(entp->mnt_type, "fuseblk.", 8) == 0)) {
			char *p = strstr(entp->mnt_opts, "user=");
			if (p &&
			    (p == entp->mnt_opts || *(p-1) == ',') &&
			    strcmp(p + 5, user) == 0) {
				found = 1;
				break;
			}
			/* /etc/mtab is a link pointing to
			   /proc/mounts: */
			else if ((p =
				  strstr(entp->mnt_opts, "user_id=")) &&
				 (p == entp->mnt_opts ||
				  *(p-1) == ',') &&
				 strncmp(p + 8, uidstr, uidlen) == 0 &&
				 (*(p+8+uidlen) == ',' ||
				  *(p+8+uidlen) == '\0')) {
				found = 1;
				break;
			}
		}
	}
	endmntent(fp);

	if (!found) {
		if (!quiet)
			fprintf(stderr,
				"%s: entry for %s not found in %s\n",
				progname, mnt, mtab);
		return -1;
	}

	return 0;
}

Project: libfuse

static int unmount_fuse(const char *mnt, int quiet, int lazy)
{
	(void) quiet;
	return fuse_mnt_umount(progname, mnt, mnt, lazy);
}

Project: libfuse

static void drop_privs(void)
{
	if (getuid() != 0) {
		oldfsuid = setfsuid(getuid());
		oldfsgid = setfsgid(getgid());
	}
}

Project: libfuse

static int find_mount_flag(const char *s, unsigned len, int *on, int *flag)
{
	int i;

	for (i = 0; mount_flags[i].opt != NULL; i++) {
		const char *opt = mount_flags[i].opt;
		if (strlen(opt) == len && strncmp(opt, s, len) == 0) {
			*on = mount_flags[i].on;
			*flag = mount_flags[i].flag;
			if (!mount_flags[i].safe && getuid() != 0) {
				*flag = 0;
				fprintf(stderr,
					"%s: unsafe option %s ignored\n",
					progname, opt);
			}
			return 1;
		}
	}
	return 0;
}

Project: libfuse

static int begins_with(const char *s, const char *beg)
{
	if (strncmp(s, beg, strlen(beg)) == 0)
		return 1;
	else
		return 0;
}

Project: libfuse

static int mount_fuse(const char *mnt, const char *opts)
{
	int res;
	int fd;
	char *dev;
	struct stat stbuf;
	char *type = NULL;
	char *source = NULL;
	char *mnt_opts = NULL;
	const char *real_mnt = mnt;
	int mountpoint_fd = -1;

	fd = open_fuse_device(&dev);
	if (fd == -1)
		return -1;

	drop_privs();
	read_conf();

	if (getuid() != 0 && mount_max != -1) {
		int mount_count = count_fuse_fs();
		if (mount_count >= mount_max) {
			fprintf(stderr, "%s: too many FUSE filesystems mounted; mount_max=N can be set in %s\n", progname, FUSE_CONF);
			goto fail_close_fd;
		}
	}

	res = check_perm(&real_mnt, &stbuf, &mountpoint_fd);
	restore_privs();
	if (res != -1)
		res = do_mount(real_mnt, &type, stbuf.st_mode & S_IFMT,
			       fd, opts, dev, &source, &mnt_opts);

	if (mountpoint_fd != -1)
		close(mountpoint_fd);

	if (res == -1)
		goto fail_close_fd;

	res = chdir("/");
	if (res == -1) {
		fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
		goto fail_close_fd;
	}

	if (geteuid() == 0) {
		res = add_mount(source, mnt, type, mnt_opts);
		if (res == -1) {
			/* Can't clean up mount in a non-racy way */
			goto fail_close_fd;
		}
	}

out_free:
	free(source);
	free(type);
	free(mnt_opts);
	free(dev);

	return fd;

fail_close_fd:
	close(fd);
	fd = -1;
	goto out_free;
}

Project: libfuse

static int add_mount(const char *source, const char *mnt, const char *type,
		     const char *opts)
{
	(void) source;
	(void) mnt;
	(void) type;
	(void) opts;
	return 0;
}

Project: libfuse

static void strip_line(char *line)
{
	char *s = strchr(line, '#');
	if (s != NULL)
		s[0] = '\0';
	for (s = line + strlen(line) - 1;
	     s >= line && isspace((unsigned char) *s); s--);
	s[1] = '\0';
	for (s = line; isspace((unsigned char) *s); s++);
	if (s != line)
		memmove(line, s, strlen(s)+1);
}

Project: libfuse

static int unmount_fuse(const char *mnt, int quiet, int lazy)
{
	int res;
	int mtablock = lock_umount();

	res = unmount_fuse_locked(mnt, quiet, lazy);
	unlock_umount(mtablock);

	return res;
}

Project: libfuse

static void usage(void)
{
	printf("%s: [options] mountpoint\n"
	       "Options:\n"
	       " -h		    print help\n"
	       " -V		    print version\n"
	       " -o opt[,opt...]   mount options\n"
	       " -u		    unmount\n"
	       " -q		    quiet\n"
	       " -z		    lazy unmount\n",
	       progname);
	exit(1);
}

Project: libfuse

static int check_is_mount(const char *last, const char *mnt)
{
	pid_t pid, p;
	int status;
	const char *a[2] = { last, mnt };

	pid = clone_newns((void *) a);
	if (pid == (pid_t) -1) {
		fprintf(stderr, "%s: failed to clone namespace: %s\n",
			progname, strerror(errno));
		return -1;
	}
	p = waitpid(pid, &status, __WCLONE);
	if (p == (pid_t) -1) {
		fprintf(stderr, "%s: waitpid failed: %s\n",
			progname, strerror(errno));
		return -1;
	}
	if (!WIFEXITED(status)) {
		fprintf(stderr, "%s: child terminated abnormally (status %i)\n",
			progname, status);
		return -1;
	}
	if (WEXITSTATUS(status) != 0)
		return -1;

	return 0;
}

Project: libfuse

static int lock_umount(void)
{
	const char *mtab_lock = _PATH_MOUNTED ".fuselock";
	int mtablock;
	int res;
	struct stat mtab_stat;

	/* /etc/mtab could be a symlink to /proc/mounts */
	if (lstat(_PATH_MOUNTED, &mtab_stat) == 0 && S_ISLNK(mtab_stat.st_mode))
		return -1;

	mtablock = open(mtab_lock, O_RDWR | O_CREAT, 0600);
	if (mtablock == -1) {
		fprintf(stderr, "%s: unable to open fuse lock file: %s\n",
			progname, strerror(errno));
		return -1;
	}
	res = lockf(mtablock, F_LOCK, 0);
	if (res < 0) {
		fprintf(stderr, "%s: error getting lock: %s\n", progname,
			strerror(errno));
		close(mtablock);
		return -1;
	}

	return mtablock;
}

Project: libfuse

static int unmount_fuse_locked(const char *mnt, int quiet, int lazy)
{
	int res;
	char *copy;
	const char *last;
	int umount_flags = lazy ? UMOUNT_DETACH : 0;

	if (getuid() != 0) {
		res = may_unmount(mnt, quiet);
		if (res == -1)
			return -1;
	}

	copy = strdup(mnt);
	if (copy == NULL) {
		fprintf(stderr, "%s: failed to allocate memory\n", progname);
		return -1;
	}

	res = chdir_to_parent(copy, &last);
	if (res == -1)
		goto out;

	if (umount_nofollow_support()) {
		umount_flags |= UMOUNT_NOFOLLOW;
	} else {
		res = check_is_mount(last, mnt);
		if (res == -1)
			goto out;
	}

	res = umount2(last, umount_flags);
	if (res == -1 && !quiet) {
		fprintf(stderr, "%s: failed to unmount %s: %s\n",
			progname, mnt, strerror(errno));
	}

out:
	if (res == -1)
		return -1;

	res = chdir("/");
	if (res == -1) {
		fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
		return -1;
	}

	return fuse_mnt_remove_mount(progname, mnt);
}

Project: libfuse

static int add_option(char **optsp, const char *opt, unsigned expand)
{
	char *newopts;
	if (*optsp == NULL)
		newopts = strdup(opt);
	else {
		unsigned oldsize = strlen(*optsp);
		unsigned newsize = oldsize + 1 + strlen(opt) + expand + 1;
		newopts = (char *) realloc(*optsp, newsize);
		if (newopts)
			sprintf(newopts + oldsize, ",%s", opt);
	}
	if (newopts == NULL) {
		fprintf(stderr, "%s: failed to allocate memory\n", progname);
		return -1;
	}
	*optsp = newopts;
	return 0;
}

Project: libfuse

static int try_open(const char *dev, char **devp, int silent)
{
	int fd = open(dev, O_RDWR);
	if (fd != -1) {
		*devp = strdup(dev);
		if (*devp == NULL) {
			fprintf(stderr, "%s: failed to allocate memory\n",
				progname);
			close(fd);
			fd = -1;
		}
	} else if (errno == ENODEV ||
		   errno == ENOENT)/* check for ENOENT too, for the udev case */
		return -2;
	else if (!silent) {
		fprintf(stderr, "%s: failed to open %s: %s\n", progname, dev,
			strerror(errno));
	}
	return fd;
}

Project: libfuse

static const char *get_user_name(void)
{
	struct passwd *pw = getpwuid(getuid());
	if (pw != NULL && pw->pw_name != NULL)
		return pw->pw_name;
	else {
		fprintf(stderr, "%s: could not determine username\n", progname);
		return NULL;
	}
}

Project: libfuse

static void parse_line(char *line, int linenum)
{
	int tmp;
	if (strcmp(line, "user_allow_other") == 0)
		user_allow_other = 1;
	else if (sscanf(line, "mount_max = %i", &tmp) == 1)
		mount_max = tmp;
	else if(line[0])
		fprintf(stderr,
			"%s: unknown parameter in %s at line %i: '%s'\n",
			progname, FUSE_CONF, linenum, line);
}

Project: libfuse

static void read_conf(void)
{
	FILE *fp = fopen(FUSE_CONF, "r");
	if (fp != NULL) {
		int linenum = 1;
		char line[256];
		int isnewline = 1;
		while (fgets(line, sizeof(line), fp) != NULL) {
			if (isnewline) {
				if (line[strlen(line)-1] == '\n') {
					strip_line(line);
					parse_line(line, linenum);
				} else {
					isnewline = 0;
				}
			} else if(line[strlen(line)-1] == '\n') {
				fprintf(stderr, "%s: reading %s: line %i too long\n", progname, FUSE_CONF, linenum);

				isnewline = 1;
			}
			if (isnewline)
				linenum ++;
		}
		if (!isnewline) {
			fprintf(stderr, "%s: reading %s: missing newline at end of file\n", progname, FUSE_CONF);

		}
		fclose(fp);
	} else if (errno != ENOENT) {
		fprintf(stderr, "%s: failed to open %s: %s\n",
			progname, FUSE_CONF, strerror(errno));
	}
}

Project: libfuse

static int count_fuse_fs(void)
{
	struct mntent *entp;
	int count = 0;
	const char *mtab = _PATH_MOUNTED;
	FILE *fp = setmntent(mtab, "r");
	if (fp == NULL) {
		fprintf(stderr, "%s: failed to open %s: %s\n", progname, mtab,
			strerror(errno));
		return -1;
	}
	while ((entp = getmntent(fp)) != NULL) {
		if (strcmp(entp->mnt_type, "fuse") == 0 ||
		    strncmp(entp->mnt_type, "fuse.", 5) == 0)
			count ++;
	}
	endmntent(fp);
	return count;
}

Project: libfuse

static int check_perm(const char **mntp, struct stat *stbuf, int *mountpoint_fd)
{
	int res;
	const char *mnt = *mntp;
	const char *origmnt = mnt;

	res = lstat(mnt, stbuf);
	if (res == -1) {
		fprintf(stderr, "%s: failed to access mountpoint %s: %s\n",
			progname, mnt, strerror(errno));
		return -1;
	}

	/* No permission checking is done for root */
	if (getuid() == 0)
		return 0;

	if (S_ISDIR(stbuf->st_mode)) {
		res = chdir(mnt);
		if (res == -1) {
			fprintf(stderr,
				"%s: failed to chdir to mountpoint: %s\n",
				progname, strerror(errno));
			return -1;
		}
		mnt = *mntp = ".";
		res = lstat(mnt, stbuf);
		if (res == -1) {
			fprintf(stderr,
				"%s: failed to access mountpoint %s: %s\n",
				progname, origmnt, strerror(errno));
			return -1;
		}

		if ((stbuf->st_mode & S_ISVTX) && stbuf->st_uid != getuid()) {
			fprintf(stderr, "%s: mountpoint %s not owned by user\n",
				progname, origmnt);
			return -1;
		}

		res = access(mnt, W_OK);
		if (res == -1) {
			fprintf(stderr, "%s: user has no write access to mountpoint %s\n",
				progname, origmnt);
			return -1;
		}
	} else if (S_ISREG(stbuf->st_mode)) {
		static char procfile[256];
		*mountpoint_fd = open(mnt, O_WRONLY);
		if (*mountpoint_fd == -1) {
			fprintf(stderr, "%s: failed to open %s: %s\n",
				progname, mnt, strerror(errno));
			return -1;
		}
		res = fstat(*mountpoint_fd, stbuf);
		if (res == -1) {
			fprintf(stderr,
				"%s: failed to access mountpoint %s: %s\n",
				progname, mnt, strerror(errno));
			return -1;
		}
		if (!S_ISREG(stbuf->st_mode)) {
			fprintf(stderr,
				"%s: mountpoint %s is no longer a regular file\n",
				progname, mnt);
			return -1;
		}

		sprintf(procfile, "/proc/self/fd/%i", *mountpoint_fd);
		*mntp = procfile;
	} else {
		fprintf(stderr,
			"%s: mountpoint %s is not a directory or a regular file\n",
			progname, mnt);
		return -1;
	}


	return 0;
}

Project: libfuse

static void show_version(void)
{
	printf("fusermount3 version: %s\n", PACKAGE_VERSION);
	exit(0);
}

Project: libfuse

static int opt_eq(const char *s, unsigned len, const char *opt)
{
	if(strlen(opt) == len && strncmp(s, opt, len) == 0)
		return 1;
	else
		return 0;
}

Project: libfuse

static int send_fd(int sock_fd, int fd)
{
	int retval;
	struct msghdr msg;
	struct cmsghdr *p_cmsg;
	struct iovec vec;
	size_t cmsgbuf[CMSG_SPACE(sizeof(fd)) / sizeof(size_t)];
	int *p_fds;
	char sendchar = 0;

	msg.msg_control = cmsgbuf;
	msg.msg_controllen = sizeof(cmsgbuf);
	p_cmsg = CMSG_FIRSTHDR(&msg);
	p_cmsg->cmsg_level = SOL_SOCKET;
	p_cmsg->cmsg_type = SCM_RIGHTS;
	p_cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
	p_fds = (int *) CMSG_DATA(p_cmsg);
	*p_fds = fd;
	msg.msg_controllen = p_cmsg->cmsg_len;
	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_iov = &vec;
	msg.msg_iovlen = 1;
	msg.msg_flags = 0;
	/* "To pass file descriptors or credentials you need to send/read at
	 * least one byte" (man 7 unix) */
	vec.iov_base = &sendchar;
	vec.iov_len = sizeof(sendchar);
	while ((retval = sendmsg(sock_fd, &msg, 0)) == -1 && errno == EINTR);
	if (retval != 1) {
		perror("sending file descriptor");
		return -1;
	}
	return 0;
}

Project: libfuse

static void restore_privs(void)
{
	if (getuid() != 0) {
		setfsuid(oldfsuid);
		setfsgid(oldfsgid);
	}
}

Project: libfuse

static int add_mount(const char *source, const char *mnt, const char *type,
		     const char *opts)
{
	return fuse_mnt_add_mount(progname, source, mnt, type, opts);
}

Project: libfuse

static int get_string_opt(const char *s, unsigned len, const char *opt,
			  char **val)
{
	int i;
	unsigned opt_len = strlen(opt);
	char *d;

	if (*val)
		free(*val);
	*val = (char *) malloc(len - opt_len + 1);
	if (!*val) {
		fprintf(stderr, "%s: failed to allocate memory\n", progname);
		return 0;
	}

	d = *val;
	s += opt_len;
	len -= opt_len;
	for (i = 0; i < len; i++) {
		if (s[i] == '\\' && i + 1 < len)
			i++;
		*d++ = s[i];
	}
	*d = '\0';
	return 1;
}

Project: libfuse

int main(int argc, char *argv[])
{
	sigset_t sigset;
	int ch;
	int fd;
	int res;
	char *origmnt;
	char *mnt;
	static int unmount = 0;
	static int lazy = 0;
	static int quiet = 0;
	char *commfd;
	int cfd;
	const char *opts = "";

	static const struct option long_opts[] = {
		{"unmount", no_argument, NULL, 'u'},
		{"lazy",    no_argument, NULL, 'z'},
		{"quiet",   no_argument, NULL, 'q'},
		{"help",    no_argument, NULL, 'h'},
		{"version", no_argument, NULL, 'V'},
		{0, 0, 0, 0}};

	progname = strdup(argv[0]);
	if (progname == NULL) {
		fprintf(stderr, "%s: failed to allocate memory\n", argv[0]);
		exit(1);
	}

	while ((ch = getopt_long(argc, argv, "hVo:uzq", long_opts,
				 NULL)) != -1) {
		switch (ch) {
		case 'h':
			usage();
			break;

		case 'V':
			show_version();
			break;

		case 'o':
			opts = optarg;
			break;

		case 'u':
			unmount = 1;
			break;

		case 'z':
			lazy = 1;
			break;

		case 'q':
			quiet = 1;
			break;

		default:
			exit(1);
		}
	}

	if (lazy && !unmount) {
		fprintf(stderr, "%s: -z can only be used with -u\n", progname);
		exit(1);
	}

	if (optind >= argc) {
		fprintf(stderr, "%s: missing mountpoint argument\n", progname);
		exit(1);
	} else if (argc > optind + 1) {
		fprintf(stderr, "%s: extra arguments after the mountpoint\n",
			progname);
		exit(1);
	}

	origmnt = argv[optind];

	drop_privs();
	mnt = fuse_mnt_resolve_path(progname, origmnt);
	if (mnt != NULL) {
		res = chdir("/");
		if (res == -1) {
			fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
			goto err_out;
		}
	}
	restore_privs();
	if (mnt == NULL)
		exit(1);

	umask(033);
	if (unmount)
		goto do_unmount;

	commfd = getenv(FUSE_COMMFD_ENV);
	if (commfd == NULL) {
		fprintf(stderr, "%s: old style mounting not supported\n",
			progname);
		goto err_out;
	}

	fd = mount_fuse(mnt, opts);
	if (fd == -1)
		goto err_out;

	cfd = atoi(commfd);
	res = send_fd(cfd, fd);
	if (res == -1)
		goto err_out;
	close(fd);

	if (!auto_unmount) {
		free(mnt);
		return 0;
	}

	/* Become a daemon and wait for the parent to exit or die.
	   ie For the control socket to get closed.
	   btw We don't want to use daemon() function here because
	   it forks and messes with the file descriptors. */
	setsid();
	res = chdir("/");
	if (res == -1) {
		fprintf(stderr, "%s: failed to chdir to '/'\n", progname);
		goto err_out;
	}

	sigfillset(&sigset);
	sigprocmask(SIG_BLOCK, &sigset, NULL);

	lazy  = 1;
	quiet = 1;

	while (1) {
		unsigned char buf[16];
		int n = recv(cfd, buf, sizeof(buf), 0);
		if (!n)
			break;

		if (n < 0) {
			if (errno == EINTR)
				continue;
			break;
		}
	}

do_unmount:
	if (geteuid() == 0)
		res = unmount_fuse(mnt, quiet, lazy);
	else {
		res = umount2(mnt, lazy ? UMOUNT_DETACH : 0);
		if (res == -1 && !quiet)
			fprintf(stderr,
				"%s: failed to unmount %s: %s\n",
				progname, mnt, strerror(errno));
	}
	if (res == -1)
		goto err_out;
	return 0;

err_out:
	free(mnt);
	exit(1);
}

Project: libfuse

static int check_is_mount_child(void *p)
{
	const char **a = p;
	const char *last = a[0];
	const char *mnt = a[1];
	int res;
	const char *procmounts = "/proc/mounts";
	int found;
	FILE *fp;
	struct mntent *entp;
	int count;

	res = mount("", "/", "", MS_PRIVATE | MS_REC, NULL);
	if (res == -1) {
		fprintf(stderr, "%s: failed to mark mounts private: %s\n",
			progname, strerror(errno));
		return 1;
	}

	fp = setmntent(procmounts, "r");
	if (fp == NULL) {
		fprintf(stderr, "%s: failed to open %s: %s\n", progname,
			procmounts, strerror(errno));
		return 1;
	}

	count = 0;
	while (getmntent(fp) != NULL)
		count++;
	endmntent(fp);

	fp = setmntent(procmounts, "r");
	if (fp == NULL) {
		fprintf(stderr, "%s: failed to open %s: %s\n", progname,
			procmounts, strerror(errno));
		return 1;
	}

	res = mount(".", "/", "", MS_BIND | MS_REC, NULL);
	if (res == -1) {
		fprintf(stderr, "%s: failed to bind parent to /: %s\n",
			progname, strerror(errno));
		return 1;
	}

	found = 0;
	while ((entp = getmntent(fp)) != NULL) {
		if (count > 0) {
			count--;
			continue;
		}
		if (entp->mnt_dir[0] == '/' &&
		    strcmp(entp->mnt_dir + 1, last) == 0) {
			found = 1;
			break;
		}
	}
	endmntent(fp);

	if (!found) {
		fprintf(stderr, "%s: %s not mounted\n", progname, mnt);
		return 1;
	}

	return 0;
}

Project: libfuse

static int get_mnt_opts(int flags, char *opts, char **mnt_optsp)
{
	int i;
	int l;

	if (!(flags & MS_RDONLY) && add_option(mnt_optsp, "rw", 0) == -1)
		return -1;

	for (i = 0; mount_flags[i].opt != NULL; i++) {
		if (mount_flags[i].on && (flags & mount_flags[i].flag) &&
		    add_option(mnt_optsp, mount_flags[i].opt, 0) == -1)
			return -1;
	}

	if (add_option(mnt_optsp, opts, 0) == -1)
		return -1;
	/* remove comma from end of opts*/
	l = strlen(*mnt_optsp);
	if ((*mnt_optsp)[l-1] == ',')
		(*mnt_optsp)[l-1] = '\0';
	if (getuid() != 0) {
		const char *user = get_user_name();
		if (user == NULL)
			return -1;

		if (add_option(mnt_optsp, "user=", strlen(user)) == -1)
			return -1;
		strcat(*mnt_optsp, user);
	}
	return 0;
}

Project: libfuse

static int try_open_fuse_device(char **devp)
{
	int fd;

	drop_privs();
	fd = try_open(FUSE_DEV, devp, 0);
	restore_privs();
	return fd;
}

Project: libfuse
File: umount.c

static int umount_nofollow_support(void)
{
	int res = umount2("", UMOUNT_UNUSED);
	if (res != -1 || errno != EINVAL)
		return 0;

	res = umount2("", UMOUNT_NOFOLLOW);
	if (res != -1 || errno != ENOENT)
		return 0;

	return 1;
}

Project: libfuse

static int chdir_to_parent(char *copy, const char **lastp)
{
	char *tmp;
	const char *parent;
	char buf[65536];
	int res;

	tmp = strrchr(copy, '/');
	if (tmp == NULL || tmp[1] == '\0') {
		fprintf(stderr, "%s: internal error: invalid abs path: <%s>\n",
			progname, copy);
		return -1;
	}
	if (tmp != copy) {
		*tmp = '\0';
		parent = copy;
		*lastp = tmp + 1;
	} else if (tmp[1] != '\0') {
		*lastp = tmp + 1;
		parent = "/";
	} else {
		*lastp = ".";
		parent = "/";
	}

	res = chdir(parent);
	if (res == -1) {
		fprintf(stderr, "%s: failed to chdir to %s: %s\n",
			progname, parent, strerror(errno));
		return -1;
	}

	if (getcwd(buf, sizeof(buf)) == NULL) {
		fprintf(stderr, "%s: failed to obtain current directory: %s\n",
			progname, strerror(errno));
		return -1;
	}
	if (strcmp(buf, parent) != 0) {
		fprintf(stderr, "%s: mountpoint moved (%s -> %s)\n", progname,
			parent, buf);
		return -1;

	}

	return 0;
}

Project: libfuse

static int count_fuse_fs(void)
{
	return 0;
}

Project: libfuse

static void unlock_umount(int mtablock)
{
	if (mtablock >= 0) {
		int res;

		res = lockf(mtablock, F_ULOCK, 0);
		if (res < 0) {
			fprintf(stderr, "%s: error releasing lock: %s\n",
				progname, strerror(errno));
		}
		close(mtablock);
	}
}

Project: libfuse

static pid_t clone_newns(void *a)
{
	char buf[131072];
	char *stack = buf + (sizeof(buf) / 2 - ((size_t) buf & 15));

#ifdef __ia64__
	extern int __clone2(int (*fn)(void *),
			    void *child_stack_base, size_t stack_size,
			    int flags, void *arg, pid_t *ptid,
			    void *tls, pid_t *ctid);

	return __clone2(check_is_mount_child, stack, sizeof(buf) / 2,
			CLONE_NEWNS, a, NULL, NULL, NULL);
#else
	return clone(check_is_mount_child, stack, CLONE_NEWNS, a);
#endif
}