Commit message: libmount: fix UID check for FUSE umount [CVE-2021-3995]

Improper UID check allows an unprivileged user to unmount FUSE
filesystems of users with similar UID.

Signed-off-by: Karel Zak <kzak@redhat.com>
CVE: CVE-2021-3995
CWE: CWE-703
Vulnerability description: A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

Project: util-linux
File: optstr.c

int mnt_optstr_fix_secontext(char **optstr,
			     char *value,
			     size_t valsz,
			     char **next)
{
	int rc = 0;
	char *p, *val, *begin, *end, *raw = NULL;
	size_t sz;

	if (!optstr || !*optstr || !value || !valsz)
		return -EINVAL;

	DBG(CXT, ul_debug("fixing SELinux context"));

	begin = value;
	end = value + valsz;

	/* the selinux contexts are quoted */
	if (*value == '"') {
		if (valsz <= 2 || *(value + valsz - 1) != '"')
			return -EINVAL;		/* improperly quoted option string */
		value++;
		valsz -= 2;
	}

	p = strndup(value, valsz);
	if (!p)
		return -ENOMEM;


	/* translate the context */
	rc = selinux_trans_to_raw_context(p, &raw);

	DBG(CXT, ul_debug("SELinux context '%s' translated to '%s'",
			p, rc == -1 ? "FAILED" : (char *) raw));

	free(p);
	if (rc == -1 ||	!raw)
		return -EINVAL;


	/* create a quoted string from the raw context */
	sz = strlen((char *) raw);
	if (!sz)
		return -EINVAL;

	p = val = malloc(valsz + 3);
	if (!val)
		return -ENOMEM;

	*p++ = '"';
	memcpy(p, raw, sz);
	p += sz;
	*p++ = '"';
	*p = '\0';

	freecon(raw);

	/* set new context */
	mnt_optstr_remove_option_at(optstr, begin, end);
	rc = insert_value(optstr, begin, val, next);
	free(val);

	return rc;
}

Project: util-linux
File: optstr.c

static int __buffer_append_option(struct ul_buffer *buf,
			const char *name, size_t namesz,
			const char *val, size_t valsz)
{
	int rc = 0;

	if (!ul_buffer_is_empty(buf))
		rc = ul_buffer_append_data(buf, ",", 1);
	if (!rc)
		rc = ul_buffer_append_data(buf, name, namesz);
	if (val && !rc) {
		/* we need to append '=' is value is empty string, see
		 * 727c689908c5e68c92aa1dd65e0d3bdb6d91c1e5 */
		rc = ul_buffer_append_data(buf, "=", 1);
		if (!rc && valsz)
			rc = ul_buffer_append_data(buf, val, valsz);
	}
	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_next_option(char **optstr, char **name, size_t *namesz,
					char **value, size_t *valuesz)
{
	if (!optstr || !*optstr)
		return -EINVAL;
	return mnt_optstr_parse_next(optstr, name, namesz, value, valuesz);
}

Project: util-linux
File: optstr.c

static int test_remove(struct libmnt_test *ts, int argc, char *argv[])
{
	const char *name;
	char *optstr;
	int rc;

	if (argc < 3)
		return -EINVAL;
	optstr = xstrdup(argv[1]);
	name = argv[2];

	rc = mnt_optstr_remove_option(&optstr, name);
	if (!rc)
		printf("result: >%s<\n", optstr);
	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_umount_setopt(struct libmnt_context *cxt, int c, char *arg)
{
	int rc = -EINVAL;

	assert(cxt);
	assert(cxt->action == MNT_ACT_UMOUNT);

	switch(c) {
	case 'n':
		rc = mnt_context_disable_mtab(cxt, TRUE);
		break;
	case 'l':
		rc = mnt_context_enable_lazy(cxt, TRUE);
		break;
	case 'f':
		rc = mnt_context_enable_force(cxt, TRUE);
		break;
	case 'v':
		rc = mnt_context_enable_verbose(cxt, TRUE);
		break;
	case 'r':
		rc = mnt_context_enable_rdonly_umount(cxt, TRUE);
		break;
	case 't':
		if (arg)
			rc = mnt_context_set_fstype(cxt, arg);
		break;
	case 'N':
		if (arg)
			rc = mnt_context_set_target_ns(cxt, arg);
		break;
	default:
		return 1;
	}

	return rc;
}

Project: util-linux
File: optstr.c

static int test_set(struct libmnt_test *ts, int argc, char *argv[])
{
	const char *value = NULL, *name;
	char *optstr;
	int rc;

	if (argc < 3)
		return -EINVAL;
	optstr = xstrdup(argv[1]);
	name = argv[2];

	if (argc == 4)
		value = argv[3];

	rc = mnt_optstr_set_option(&optstr, name, value);
	if (!rc)
		printf("result: >%s<\n", optstr);
	free(optstr);
	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_remove_option(char **optstr, const char *name)
{
	struct libmnt_optloc ol = MNT_INIT_OPTLOC;
	int rc;

	if (!optstr || !name)
		return -EINVAL;

	rc = mnt_optstr_locate_option(*optstr, name, &ol);
	if (rc != 0)
		return rc;

	mnt_optstr_remove_option_at(optstr, ol.begin, ol.end);
	return 0;
}

Project: util-linux
File: optstr.c

static int mnt_optstr_locate_option(char *optstr, const char *name,
					struct libmnt_optloc *ol)
{
	char *n;
	size_t namesz, nsz;
	int rc;

	if (!optstr)
		return 1;

	assert(name);

	namesz = strlen(name);

	do {
		rc = mnt_optstr_parse_next(&optstr, &n, &nsz,
					&ol->value, &ol->valsz);
		if (rc)
			break;

		if (namesz == nsz && strncmp(n, name, nsz) == 0) {
			ol->begin = n;
			ol->end = *(optstr - 1) == ',' ? optstr - 1 : optstr;
			ol->namesz = nsz;
			return 0;
		}
	} while(1);

	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_fix_user(char **optstr)
{
	char *username;
	struct libmnt_optloc ol = MNT_INIT_OPTLOC;
	int rc = 0;

	DBG(CXT, ul_debug("fixing user"));

	rc = mnt_optstr_locate_option(*optstr, "user", &ol);
	if (rc)
		return rc == 1 ? 0 : rc;	/* 1: user= not found */

	username = mnt_get_username(getuid());
	if (!username)
		return -ENOMEM;

	if (!ol.valsz || (ol.value && strncmp(ol.value, username, ol.valsz) != 0)) {
		if (ol.valsz)
			/* remove old value */
			mnt_optstr_remove_option_at(optstr, ol.value, ol.end);

		rc = insert_value(optstr, ol.value ? ol.value : ol.end,
				  username, NULL);
	}

	free(username);
	return rc;
}

Project: util-linux
File: optstr.c

static int test_prepend(struct libmnt_test *ts, int argc, char *argv[])
{
	const char *value = NULL, *name;
	char *optstr;
	int rc;

	if (argc < 3)
		return -EINVAL;
	optstr = xstrdup(argv[1]);
	name = argv[2];

	if (argc == 4)
		value = argv[3];

	rc = mnt_optstr_prepend_option(&optstr, name, value);
	if (!rc)
		printf("result: >%s<\n", optstr);
	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

static int lookup_umount_fs_by_mountinfo(struct libmnt_context *cxt, const char *tgt)
{
	struct libmnt_fs *fs = NULL;
	int rc;

	assert(cxt);
	assert(cxt->fs);

	DBG(CXT, ul_debugobj(cxt, " lookup by mountinfo"));

	/* search */
	rc = __mtab_find_umount_fs(cxt, tgt, &fs);
	if (rc != 0)
		return rc;

	/* apply result */
	if (fs != cxt->fs) {
		mnt_fs_set_source(cxt->fs, NULL);
		mnt_fs_set_target(cxt->fs, NULL);

		if (!mnt_copy_fs(cxt->fs, fs)) {
			DBG(CXT, ul_debugobj(cxt, "  failed to copy FS"));
			return -errno;
		}
		DBG(CXT, ul_debugobj(cxt, "  mtab applied"));
	}

	cxt->flags |= MNT_FL_TAB_APPLIED;
	return 0;
}

Project: util-linux
File: optstr.c

int mnt_optstr_deduplicate_option(char **optstr, const char *name)
{
	int rc;
	char *begin = NULL, *end = NULL, *opt;

	if (!optstr || !name)
		return -EINVAL;

	opt = *optstr;
	do {
		struct libmnt_optloc ol = MNT_INIT_OPTLOC;

		rc = mnt_optstr_locate_option(opt, name, &ol);
		if (!rc) {
			if (begin) {
				/* remove the previous instance */
				size_t shift = strlen(*optstr);

				mnt_optstr_remove_option_at(optstr, begin, end);

				/* now all the offsets are not valid anymore - recount */
				shift -= strlen(*optstr);
				ol.begin -= shift;
				ol.end -= shift;
			}
			begin = ol.begin;
			end = ol.end;
			opt = end && *end ? end + 1 : NULL;
		}
		if (opt == NULL)
			break;
	} while (rc == 0 && *opt);

	return rc < 0 ? rc : begin ? 0 : 1;
}

Project: util-linux
File: optstr.c

int mnt_optstr_fix_gid(char **optstr, char *value, size_t valsz, char **next)
{
	char *end;

	if (!optstr || !*optstr || !value || !valsz)
		return -EINVAL;

	DBG(CXT, ul_debug("fixing gid"));

	end = value + valsz;

	if (valsz == 7 && !strncmp(value, "usergid", 7) &&
	    (*(value + 7) == ',' || !*(value + 7)))
		return set_uint_value(optstr, getgid(), value, end, next);

	if (!isdigit(*value)) {
		int rc;
		gid_t id;
		char *p = strndup(value, valsz);
		if (!p)
			return -ENOMEM;
		rc = mnt_get_gid(p, &id);
		free(p);

		if (!rc)
			return set_uint_value(optstr, id, value, end, next);

	}

	if (next) {
		/* nothing */
		*next = value + valsz;
		if (**next == ',')
			(*next)++;
	}
	return 0;
}

Project: util-linux
File: context_umount.c

static int evaluate_permissions(struct libmnt_context *cxt)
{
	struct libmnt_table *fstab;
	unsigned long u_flags = 0;
	const char *tgt, *src, *optstr;
	int rc = 0, ok = 0;
	struct libmnt_fs *fs;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	if (!mnt_context_is_restricted(cxt))
		 return 0;		/* superuser mount */

	DBG(CXT, ul_debugobj(cxt, "umount: evaluating permissions"));

	if (!mnt_context_tab_applied(cxt)) {
		DBG(CXT, ul_debugobj(cxt,
				"cannot find %s in mtab and you are not root",
				mnt_fs_get_target(cxt->fs)));
		goto eperm;
	}

	if (cxt->user_mountflags & MNT_MS_UHELPER) {
		/* on uhelper= mount option based helper */
		rc = prepare_helper_from_options(cxt, "uhelper");
		if (rc)
			return rc;
		if (cxt->helper)
			return 0;	/* we'll call /sbin/umount.<uhelper> */
	}

	/*
	 * Check if this is a fuse mount for the current user,
	 * if so then unmounting is allowed
	 */
	if (is_fuse_usermount(cxt, &rc)) {
		DBG(CXT, ul_debugobj(cxt, "fuse user mount, umount is allowed"));
		return 0;
	}
	if (rc)
		return rc;

	/*
	 * User mounts have to be in /etc/fstab
	 */
	rc = mnt_context_get_fstab(cxt, &fstab);
	if (rc)
		return rc;

	tgt = mnt_fs_get_target(cxt->fs);
	src = mnt_fs_get_source(cxt->fs);

	if (mnt_fs_get_bindsrc(cxt->fs)) {
		src = mnt_fs_get_bindsrc(cxt->fs);
		DBG(CXT, ul_debugobj(cxt,
				"umount: using bind source: %s", src));
	}

	/* If fstab contains the two lines
	 *	/dev/sda1 /mnt/zip auto user,noauto  0 0
	 *	/dev/sda4 /mnt/zip auto user,noauto  0 0
	 * then "mount /dev/sda4" followed by "umount /mnt/zip" used to fail.
	 * So, we must not look for the file, but for the pair (dev,file) in fstab.
	  */
	fs = mnt_table_find_pair(fstab, src, tgt, MNT_ITER_FORWARD);
	if (!fs) {
		/*
		 * It's possible that there is /path/file.img in fstab and
		 * /dev/loop0 in mtab -- then we have to check the relation
		 * between loopdev and the file.
		 */
		fs = mnt_table_find_target(fstab, tgt, MNT_ITER_FORWARD);
		if (fs) {
			struct libmnt_cache *cache = mnt_context_get_cache(cxt);
			const char *sp = mnt_fs_get_srcpath(cxt->fs);		/* devname from mtab */
			const char *dev = sp && cache ? mnt_resolve_path(sp, cache) : sp;

			if (!dev || !is_associated_fs(dev, fs))
				fs = NULL;
		}
		if (!fs) {
			DBG(CXT, ul_debugobj(cxt,
					"umount %s: mtab disagrees with fstab",
					tgt));
			goto eperm;
		}
	}

	/*
	 * User mounting and unmounting is allowed only if fstab contains one
	 * of the options `user', `users' or `owner' or `group'.
	 *
	 * The option `users' allows arbitrary users to mount and unmount -
	 * this may be a security risk.
	 *
	 * The options `user', `owner' and `group' only allow unmounting by the
	 * user that mounted (visible in mtab).
	 */
	optstr = mnt_fs_get_user_options(fs);	/* FSTAB mount options! */
	if (!optstr)
		goto eperm;

	if (mnt_optstr_get_flags(optstr, &u_flags,
				mnt_get_builtin_optmap(MNT_USERSPACE_MAP)))
		goto eperm;

	if (u_flags & MNT_MS_USERS) {
		DBG(CXT, ul_debugobj(cxt,
			"umount: promiscuous setting ('users') in fstab"));
		return 0;
	}
	/*
	 * Check user=<username> setting from mtab if there is a user, owner or
	 * group option in /etc/fstab
	 */
	if (u_flags & (MNT_MS_USER | MNT_MS_OWNER | MNT_MS_GROUP)) {

		char *curr_user;
		char *mtab_user = NULL;
		size_t sz;
		struct libmnt_ns *ns_old;

		DBG(CXT, ul_debugobj(cxt,
				"umount: checking user=<username> from mtab"));

		ns_old = mnt_context_switch_origin_ns(cxt);
		if (!ns_old)
			return -MNT_ERR_NAMESPACE;

		curr_user = mnt_get_username(getuid());

		if (!mnt_context_switch_ns(cxt, ns_old)) {
			free(curr_user);
			return -MNT_ERR_NAMESPACE;
		}
		if (!curr_user) {
			DBG(CXT, ul_debugobj(cxt, "umount %s: cannot "
				"convert %d to username", tgt, getuid()));
			goto eperm;
		}

		/* get options from mtab */
		optstr = mnt_fs_get_user_options(cxt->fs);
		if (optstr && !mnt_optstr_get_option(optstr,
					"user", &mtab_user, &sz) && sz)
			ok = !strncmp(curr_user, mtab_user, sz);

		free(curr_user);
	}

	if (ok) {
		DBG(CXT, ul_debugobj(cxt, "umount %s is allowed", tgt));
		return 0;
	}
eperm:
	DBG(CXT, ul_debugobj(cxt, "umount is not allowed for you"));
	return -EPERM;
}

Project: util-linux
File: optstr.c

static int test_split(struct libmnt_test *ts, int argc, char *argv[])
{
	char *optstr, *user = NULL, *fs = NULL, *vfs = NULL;
	int rc;

	if (argc < 2)
		return -EINVAL;

	optstr = xstrdup(argv[1]);

	rc = mnt_split_optstr(optstr, &user, &vfs, &fs, 0, 0);
	if (!rc) {
		printf("user : %s\n", user);
		printf("vfs  : %s\n", vfs);
		printf("fs   : %s\n", fs);
	}

	free(user);
	free(vfs);
	free(fs);
	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

static int do_umount(struct libmnt_context *cxt)
{
	int rc = 0, flags = 0;
	const char *src, *target;
	char *tgtbuf = NULL;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
	assert(cxt->syscall_status == 1);

	if (cxt->helper)
		return exec_helper(cxt);

	src = mnt_fs_get_srcpath(cxt->fs);
	target = mnt_fs_get_target(cxt->fs);

	if (!target)
		return -EINVAL;

	DBG(CXT, ul_debugobj(cxt, "do umount"));

	if (mnt_context_is_restricted(cxt) && !mnt_context_is_fake(cxt)) {
		/*
		 * extra paranoia for non-root users
		 * -- chdir to the parent of the mountpoint and use NOFOLLOW
		 *    flag to avoid races and symlink attacks.
		 */
		if (umount_nofollow_support())
			flags |= UMOUNT_NOFOLLOW;

		rc = mnt_chdir_to_parent(target, &tgtbuf);
		if (rc)
			return rc;
		target = tgtbuf;
	}

	if (mnt_context_is_lazy(cxt))
		flags |= MNT_DETACH;

	if (mnt_context_is_force(cxt))
		flags |= MNT_FORCE;

	DBG(CXT, ul_debugobj(cxt, "umount(2) [target='%s', flags=0x%08x]%s",
				target, flags,
				mnt_context_is_fake(cxt) ? " (FAKE)" : ""));

	if (mnt_context_is_fake(cxt))
		rc = 0;
	else {
		rc = flags ? umount2(target, flags) : umount(target);
		if (rc < 0)
			cxt->syscall_status = -errno;
		free(tgtbuf);
	}

	/*
	 * try remount read-only
	 */
	if (rc < 0
	    && cxt->syscall_status == -EBUSY
	    && mnt_context_is_rdonly_umount(cxt)
	    && src) {

		mnt_context_set_mflags(cxt, (cxt->mountflags |
					     MS_REMOUNT | MS_RDONLY));
		mnt_context_enable_loopdel(cxt, FALSE);

		DBG(CXT, ul_debugobj(cxt,
			"umount(2) failed [errno=%d] -- trying to remount read-only",
			-cxt->syscall_status));

		rc = mount(src, mnt_fs_get_target(cxt->fs), NULL,
			    MS_REMOUNT | MS_RDONLY, NULL);
		if (rc < 0) {
			cxt->syscall_status = -errno;
			DBG(CXT, ul_debugobj(cxt,
				"read-only re-mount(2) failed [errno=%d]",
				-cxt->syscall_status));

			return -cxt->syscall_status;
		}
		cxt->syscall_status = 0;
		DBG(CXT, ul_debugobj(cxt, "read-only re-mount(2) success"));
		return 0;
	}

	if (rc < 0) {
		DBG(CXT, ul_debugobj(cxt, "umount(2) failed [errno=%d]",
			-cxt->syscall_status));
		return -cxt->syscall_status;
	}

	cxt->syscall_status = 0;
	DBG(CXT, ul_debugobj(cxt, "umount(2) success"));
	return 0;
}

Project: util-linux
File: optstr.c

int mnt_optstr_remove_option_at(char **optstr, char *begin, char *end)
{
	size_t sz;

	if (!optstr || !begin || !end)
		return -EINVAL;

	if ((begin == *optstr || *(begin - 1) == ',') && *end == ',')
		end++;

	sz = strlen(end);

	memmove(begin, end, sz + 1);
	if (!*begin && (begin > *optstr) && *(begin - 1) == ',')
		*(begin - 1) = '\0';

	return 0;
}

Project: util-linux
File: optstr.c

int main(int argc, char *argv[])
{
	struct libmnt_test tss[] = {
		{ "--append", test_append, "<optstr> <name> [<value>]  append value to optstr" },
		{ "--prepend",test_prepend,"<optstr> <name> [<value>]  prepend value to optstr" },
		{ "--set",    test_set,    "<optstr> <name> [<value>]  (un)set value" },
		{ "--get",    test_get,    "<optstr> <name>            search name in optstr" },
		{ "--remove", test_remove, "<optstr> <name>            remove name in optstr" },
		{ "--dedup",  test_dedup,  "<optstr> <name>            deduplicate name in optstr" },
		{ "--split",  test_split,  "<optstr>                   split into FS, VFS and userspace" },
		{ "--flags",  test_flags,  "<optstr>                   convert options to MS_* flags" },
		{ "--apply",  test_apply,  "--{linux,user} <optstr> <mask>    apply mask to optstr" },
		{ "--fix",    test_fix,    "<optstr>                   fix uid=, gid=, user, and context=" },

		{ NULL }
	};
	return  mnt_run_test(tss, argc, argv);
}

Project: util-linux
File: optstr.c

insert_value(char **str, char *pos, const char *substr, char **next)
{
	size_t subsz = strlen(substr);			/* substring size */
	size_t strsz = strlen(*str);
	size_t possz = strlen(pos);
	size_t posoff;
	char *p;
	int sep;

	/* is it necessary to prepend '=' before the substring ? */
	sep = !(pos > *str && *(pos - 1) == '=');

	/* save an offset of the place where we need to add substr */
	posoff = pos - *str;

	p = realloc(*str, strsz + sep + subsz + 1);
	if (!p)
		return -ENOMEM;

	/* zeroize the newly allocated memory -- valgrind loves us... */
	memset(p + strsz, 0, sep + subsz + 1);

	/* set pointers to the reallocated string */
	*str = p;
	pos = p + posoff;

	if (possz)
		/* create a room for the new substring */
		memmove(pos + subsz + sep, pos, possz + 1);
	if (sep)
		*pos++ = '=';

	memcpy(pos, substr, subsz);

	if (next) {
		/* set pointer to the next option */
		*next = pos + subsz;
		if (**next == ',')
			(*next)++;
	}
	return 0;
}

Project: util-linux
File: optstr.c

int mnt_split_optstr(const char *optstr, char **user, char **vfs,
		     char **fs, int ignore_user, int ignore_vfs)
{
	int rc = 0;
	char *name, *val, *str = (char *) optstr;
	size_t namesz, valsz, chunsz;
	struct libmnt_optmap const *maps[2];
	struct ul_buffer xvfs = UL_INIT_BUFFER,
			 xfs = UL_INIT_BUFFER,
			 xuser = UL_INIT_BUFFER;

	if (!optstr)
		return -EINVAL;

	maps[0] = mnt_get_builtin_optmap(MNT_LINUX_MAP);
	maps[1] = mnt_get_builtin_optmap(MNT_USERSPACE_MAP);

	chunsz = strlen(optstr) / 2;

	while (!mnt_optstr_next_option(&str, &name, &namesz, &val, &valsz)) {
		struct ul_buffer *buf = NULL;
		const struct libmnt_optmap *ent = NULL;
		const struct libmnt_optmap *m =
			 mnt_optmap_get_entry(maps, 2, name, namesz, &ent);

		if (ent && !ent->id)
			continue;	/* ignore undefined options (comments) */

		/* ignore name=<value> if options map expects <name> only */
		if (valsz && mnt_optmap_entry_novalue(ent))
			m = NULL;

		if (ent && m && m == maps[0] && vfs) {
			if (ignore_vfs && (ent->mask & ignore_vfs))
				continue;
			if (vfs)
				buf = &xvfs;
		} else if (ent && m && m == maps[1] && user) {
			if (ignore_user && (ent->mask & ignore_user))
				continue;
			if (user)
				buf = &xuser;
		} else if (!m && fs) {
			if (fs)
				buf = &xfs;
		}

		if (buf) {
			if (ul_buffer_is_empty(buf))
				ul_buffer_set_chunksize(buf, chunsz);
			rc = __buffer_append_option(buf, name, namesz, val, valsz);
		}
		if (rc)
			break;
	}

	if (vfs)
		*vfs  = rc ? NULL : ul_buffer_get_data(&xvfs, NULL, NULL);
	if (fs)
		*fs   = rc ? NULL : ul_buffer_get_data(&xfs, NULL, NULL);
	if (user)
		*user = rc ? NULL : ul_buffer_get_data(&xuser, NULL, NULL);
	if (rc) {
		ul_buffer_free_data(&xvfs);
		ul_buffer_free_data(&xfs);
		ul_buffer_free_data(&xuser);
	}

	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_prepare_umount(struct libmnt_context *cxt)
{
	int rc;
	struct libmnt_ns *ns_old;

	if (!cxt || !cxt->fs || mnt_fs_is_swaparea(cxt->fs))
		return -EINVAL;
	if (!mnt_context_get_source(cxt) && !mnt_context_get_target(cxt))
		return -EINVAL;
	if (cxt->flags & MNT_FL_PREPARED)
		return 0;

	assert(cxt->helper_exec_status == 1);
	assert(cxt->syscall_status == 1);

	free(cxt->helper);	/* be paranoid */
	cxt->helper = NULL;
	cxt->action = MNT_ACT_UMOUNT;

	ns_old = mnt_context_switch_target_ns(cxt);
	if (!ns_old)
		return -MNT_ERR_NAMESPACE;

	rc = lookup_umount_fs(cxt);
	if (!rc)
		rc = mnt_context_merge_mflags(cxt);
	if (!rc)
		rc = evaluate_permissions(cxt);

	if (!rc && !cxt->helper) {

		if (cxt->user_mountflags & MNT_MS_HELPER)
			/* on helper= mount option based helper */
			rc = prepare_helper_from_options(cxt, "helper");

		if (!rc && !cxt->helper)
			/* on fstype based helper */
			rc = mnt_context_prepare_helper(cxt, "umount", NULL);
	}

	if (!rc && (cxt->user_mountflags & MNT_MS_LOOP))
		/* loop option explicitly specified in mtab, detach this loop */
		mnt_context_enable_loopdel(cxt, TRUE);

	if (!rc && mnt_context_is_loopdel(cxt) && cxt->fs) {
		const char *src = mnt_fs_get_srcpath(cxt->fs);

		if (src && (!is_loopdev(src) || loopdev_is_autoclear(src)))
			mnt_context_enable_loopdel(cxt, FALSE);
	}

	if (rc) {
		DBG(CXT, ul_debugobj(cxt, "umount: preparing failed"));
		return rc;
	}
	cxt->flags |= MNT_FL_PREPARED;

	if (!mnt_context_switch_ns(cxt, ns_old))
		return -MNT_ERR_NAMESPACE;

	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_get_umount_excode(
			struct libmnt_context *cxt,
			int rc,
			char *buf,
			size_t bufsz)
{
	if (mnt_context_helper_executed(cxt))
		/*
		 * /sbin/umount.<type> called, return status
		 */
		return mnt_context_get_helper_status(cxt);

	if (rc == 0 && mnt_context_get_status(cxt) == 1)
		/*
		 * Libmount success && syscall success.
		 */
		return MNT_EX_SUCCESS;

	if (!mnt_context_syscall_called(cxt)) {
		/*
		 * libmount errors (extra library checks)
		 */
		if (rc == -EPERM && !mnt_context_tab_applied(cxt)) {
			/* failed to evaluate permissions because not found
			 * relevant entry in mtab */
			if (buf)
				snprintf(buf, bufsz, _("not mounted"));
			return MNT_EX_USAGE;
		}

		if (rc == -MNT_ERR_LOCK) {
			if (buf)
				snprintf(buf, bufsz, _("locking failed"));
			return MNT_EX_FILEIO;
		}

		if (rc == -MNT_ERR_NAMESPACE) {
			if (buf)
				snprintf(buf, bufsz, _("failed to switch namespace"));
			return MNT_EX_SYSERR;
		}
		return mnt_context_get_generic_excode(rc, buf, bufsz,
					_("umount failed: %m"));

	} if (mnt_context_get_syscall_errno(cxt) == 0) {
		/*
		 * umount(2) syscall success, but something else failed
		 * (probably error in mtab processing).
		 */
		if (rc == -MNT_ERR_LOCK) {
			if (buf)
				snprintf(buf, bufsz, _("filesystem was unmounted, but failed to update userspace mount table"));
			return MNT_EX_FILEIO;
		}

		if (rc == -MNT_ERR_NAMESPACE) {
			if (buf)
				snprintf(buf, bufsz, _("filesystem was unmounted, but failed to switch namespace back"));
			return MNT_EX_SYSERR;

		}

		if (rc < 0)
			return mnt_context_get_generic_excode(rc, buf, bufsz,
				_("filesystem was unmounted, but any subsequent operation failed: %m"));

		return MNT_EX_SOFTWARE;	/* internal error */
	}

	/*
	 * umount(2) errors
	 */
	if (buf) {
		int syserr = mnt_context_get_syscall_errno(cxt);

		switch (syserr) {
		case ENXIO:
			snprintf(buf, bufsz, _("invalid block device"));	/* ??? */
			break;
		case EINVAL:
			snprintf(buf, bufsz, _("not mounted"));
			break;
		case EIO:
			snprintf(buf, bufsz, _("can't write superblock"));
			break;
		case EBUSY:
			snprintf(buf, bufsz, _("target is busy"));
			break;
		case ENOENT:
			snprintf(buf, bufsz, _("no mount point specified"));
			break;
		case EPERM:
			snprintf(buf, bufsz, _("must be superuser to unmount"));
			break;
		case EACCES:
			snprintf(buf, bufsz, _("block devices are not permitted on filesystem"));
			break;
		default:
			return mnt_context_get_generic_excode(syserr, buf, bufsz,_("umount(2) system call failed: %m"));
		}
	}
	return MNT_EX_FAIL;
}

Project: util-linux
File: optstr.c

int mnt_optstr_set_option(char **optstr, const char *name, const char *value)
{
	struct libmnt_optloc ol = MNT_INIT_OPTLOC;
	char *nameend;
	int rc = 1;

	if (!optstr || !name)
		return -EINVAL;

	if (*optstr)
		rc = mnt_optstr_locate_option(*optstr, name, &ol);
	if (rc < 0)
		return rc;			/* parse error */
	if (rc == 1)
		return mnt_optstr_append_option(optstr, name, value);	/* not found */

	nameend = ol.begin + ol.namesz;

	if (value == NULL && ol.value && ol.valsz)
		/* remove unwanted "=value" */
		mnt_optstr_remove_option_at(optstr, nameend, ol.end);

	else if (value && ol.value == NULL)
		/* insert "=value" */
		rc = insert_value(optstr, nameend, value, NULL);

	else if (value && ol.value && strlen(value) == ol.valsz)
		/* simply replace =value */
		memcpy(ol.value, value, ol.valsz);

	else if (value && ol.value) {
		mnt_optstr_remove_option_at(optstr, nameend, ol.end);
		rc = insert_value(optstr, nameend, value, NULL);
	}
	return rc;
}

Project: util-linux
File: optstr.c

static int test_append(struct libmnt_test *ts, int argc, char *argv[])
{
	const char *value = NULL, *name;
	char *optstr;
	int rc;

	if (argc < 3)
		return -EINVAL;
	optstr = xstrdup(argv[1]);
	name = argv[2];

	if (argc == 4)
		value = argv[3];

	rc = mnt_optstr_append_option(&optstr, name, value);
	if (!rc)
		printf("result: >%s<\n", optstr);
	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_finalize_umount(struct libmnt_context *cxt)
{
	int rc;

	assert(cxt);
	assert(cxt->fs);
	assert((cxt->flags & MNT_FL_PREPARED));
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	rc = mnt_context_prepare_update(cxt);
	if (!rc)
		rc = mnt_context_update_tabs(cxt);
	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_umount(struct libmnt_context *cxt)
{
	int rc;
	struct libmnt_ns *ns_old;

	assert(cxt);
	assert(cxt->fs);
	assert(cxt->helper_exec_status == 1);
	assert(cxt->syscall_status == 1);

	DBG(CXT, ul_debugobj(cxt, "umount: %s", mnt_context_get_target(cxt)));

	ns_old = mnt_context_switch_target_ns(cxt);
	if (!ns_old)
		return -MNT_ERR_NAMESPACE;

	rc = mnt_context_prepare_umount(cxt);
	if (!rc)
		rc = mnt_context_prepare_update(cxt);
	if (!rc)
		rc = mnt_context_do_umount(cxt);
	if (!rc)
		rc = mnt_context_update_tabs(cxt);

	if (!mnt_context_switch_ns(cxt, ns_old))
		return -MNT_ERR_NAMESPACE;

	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_get_option(const char *optstr, const char *name,
			  char **value, size_t *valsz)
{
	struct libmnt_optloc ol = MNT_INIT_OPTLOC;
	int rc;

	if (!optstr || !name)
		return -EINVAL;

	rc = mnt_optstr_locate_option((char *) optstr, name, &ol);
	if (!rc) {
		if (value)
			*value = ol.value;
		if (valsz)
			*valsz = ol.valsz;
	}
	return rc;
}

Project: util-linux
File: optstr.c

static int test_flags(struct libmnt_test *ts, int argc, char *argv[])
{
	char *optstr;
	int rc;
	unsigned long fl = 0;

	if (argc < 2)
		return -EINVAL;

	optstr = xstrdup(argv[1]);

	rc = mnt_optstr_get_flags(optstr, &fl, mnt_get_builtin_optmap(MNT_LINUX_MAP));
	if (rc)
		return rc;
	printf("mountflags:           0x%08lx\n", fl);

	fl = 0;
	rc = mnt_optstr_get_flags(optstr, &fl, mnt_get_builtin_optmap(MNT_USERSPACE_MAP));
	if (rc)
		return rc;
	printf("userspace-mountflags: 0x%08lx\n", fl);

	free(optstr);
	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_apply_flags(char **optstr, unsigned long flags,
				const struct libmnt_optmap *map)
{
	struct libmnt_optmap const *maps[1];
	char *name, *next, *val;
	size_t namesz = 0, valsz = 0, multi = 0;
	unsigned long fl;
	int rc = 0;

	if (!optstr || !map)
		return -EINVAL;

	DBG(CXT, ul_debug("applying 0x%08lx flags to '%s'", flags, *optstr));

	maps[0] = map;
	next = *optstr;
	fl = flags;

	/*
	 * There is a convention that 'rw/ro' flags are always at the beginning of
	 * the string (although the 'rw' is unnecessary).
	 */
	if (map == mnt_get_builtin_optmap(MNT_LINUX_MAP)) {
		const char *o = (fl & MS_RDONLY) ? "ro" : "rw";

		if (next &&
		    (!strncmp(next, "rw", 2) || !strncmp(next, "ro", 2)) &&
		    (*(next + 2) == '\0' || *(next + 2) == ',')) {

			/* already set, be paranoid and fix it */
			memcpy(next, o, 2);
		} else {
			rc = mnt_optstr_prepend_option(optstr, o, NULL);
			if (rc)
				goto err;
			next = *optstr;		/* because realloc() */
		}
		fl &= ~MS_RDONLY;
		next += 2;
		if (*next == ',')
			next++;
	}

	if (next && *next) {
		/*
		 * scan @optstr and remove options that are missing in
		 * @flags
		 */
		while(!mnt_optstr_next_option(&next, &name, &namesz,
							&val, &valsz)) {
			const struct libmnt_optmap *ent;

			if (mnt_optmap_get_entry(maps, 1, name, namesz, &ent)) {
				/*
				 * remove unwanted option (rw/ro is already set)
				 */
				if (!ent || !ent->id)
					continue;
				/* ignore name=<value> if options map expects <name> only */
				if (valsz && mnt_optmap_entry_novalue(ent))
					continue;

				if (ent->id == MS_RDONLY ||
				    (ent->mask & MNT_INVERT) ||
				    (fl & ent->id) != (unsigned long) ent->id) {

					char *end = val ? val + valsz :
							  name + namesz;
					next = name;
					rc = mnt_optstr_remove_option_at(
							optstr, name, end);
					if (rc)
						goto err;
				}
				if (!(ent->mask & MNT_INVERT)) {
					/* allow options with prefix (X-mount.foo,X-mount.bar) more than once */
					if (ent->mask & MNT_PREFIX)
						multi |= ent->id;
					else
						fl &= ~ent->id;
					if (ent->id & MS_REC)
						fl |= MS_REC;
				}
			}
		}
	}

	/* remove from flags options which are allowed more than once */
	fl &= ~multi;

	/* add missing options (but ignore fl if contains MS_REC only) */
	if (fl && fl != MS_REC) {

		const struct libmnt_optmap *ent;
		struct ul_buffer buf = UL_INIT_BUFFER;
		size_t sz;
		char *p;

		ul_buffer_refer_string(&buf, *optstr);

		for (ent = map; ent && ent->name; ent++) {
			if ((ent->mask & MNT_INVERT)
			    || ent->id == 0
			    || (fl & ent->id) != (unsigned long) ent->id)
				continue;

			/* don't add options which require values (e.g. offset=%d) */
			p = strchr(ent->name, '=');
			if (p) {
				if (p > ent->name && *(p - 1) == '[')
					p--;			/* name[=] */
				else
					continue;		/* name= */
				sz = p - ent->name;
			} else
				sz = strlen(ent->name);

			rc = __buffer_append_option(&buf, ent->name, sz, NULL, 0);
			if (rc)
				goto err;
		}

		*optstr = ul_buffer_get_data(&buf, NULL, NULL);
	}

	DBG(CXT, ul_debug("new optstr '%s'", *optstr));
	return rc;
err:
	DBG(CXT, ul_debug("failed to apply flags [rc=%d]", rc));
	return rc;
}

Project: util-linux
File: context_umount.c

static int is_associated_fs(const char *devname, struct libmnt_fs *fs)
{
	uintmax_t offset = 0;
	const char *src, *optstr;
	char *val;
	size_t valsz;
	int flags = 0;

	/* check if it begins with /dev/loop */
	if (strncmp(devname, _PATH_DEV_LOOP, sizeof(_PATH_DEV_LOOP) - 1) != 0)
		return 0;

	src = mnt_fs_get_srcpath(fs);
	if (!src)
		return 0;

	/* check for the offset option in @fs */
	optstr = mnt_fs_get_user_options(fs);

	if (optstr &&
	    mnt_optstr_get_option(optstr, "offset", &val, &valsz) == 0) {
		flags |= LOOPDEV_FL_OFFSET;

		if (mnt_parse_offset(val, valsz, &offset) != 0)
			return 0;
	}

	return loopdev_is_used(devname, src, offset, 0, flags);
}

Project: util-linux
File: optstr.c

static int mnt_optstr_parse_next(char **optstr,	 char **name, size_t *namesz,
					char **value, size_t *valsz)
{
	int open_quote = 0;
	char *start = NULL, *stop = NULL, *p, *sep = NULL;
	char *optstr0;

	assert(optstr);
	assert(*optstr);

	optstr0 = *optstr;

	if (name)
		*name = NULL;
	if (namesz)
		*namesz = 0;
	if (value)
		*value = NULL;
	if (valsz)
		*valsz = 0;

	/* trim leading commas as to not invalidate option
	 * strings with multiple consecutive commas */
	while (optstr0 && *optstr0 == ',')
		optstr0++;

	for (p = optstr0; p && *p; p++) {
		if (!start)
			start = p;		/* beginning of the option item */
		if (*p == '"')
			open_quote ^= 1;	/* reverse the status */
		if (open_quote)
			continue;		/* still in quoted block */
		if (!sep && p > start && *p == '=')
			sep = p;		/* name and value separator */
		if (*p == ',')
			stop = p;		/* terminate the option item */
		else if (*(p + 1) == '\0')
			stop = p + 1;		/* end of optstr */
		if (!start || !stop)
			continue;
		if (stop <= start)
			goto error;

		if (name)
			*name = start;
		if (namesz)
			*namesz = sep ? sep - start : stop - start;
		*optstr = *stop ? stop + 1 : stop;

		if (sep) {
			if (value)
				*value = sep + 1;
			if (valsz)
				*valsz = stop - sep - 1;
		}
		return 0;
	}

	return 1;				/* end of optstr */

error:
	DBG(OPTIONS, ul_debug("parse error: \"%s\"", optstr0));
	return -EINVAL;
}

Project: util-linux
File: optstr.c

int mnt_match_options(const char *optstr, const char *pattern)
{
	char *name, *pat = (char *) pattern;
	char *buf, *patval;
	size_t namesz = 0, patvalsz = 0;
	int match = 1;

	if (!pattern && !optstr)
		return 1;
	if (!pattern)
		return 0;

	buf = malloc(strlen(pattern) + 1);
	if (!buf)
		return 0;

	/* walk on pattern string
	 */
	while (match && !mnt_optstr_next_option(&pat, &name, &namesz,
						&patval, &patvalsz)) {
		char *val;
		size_t sz;
		int no = 0, rc;

		if (*name == '+')
			name++, namesz--;
		else if ((no = (startswith(name, "no") != NULL)))
			name += 2, namesz -= 2;

		xstrncpy(buf, name, namesz + 1);

		rc = mnt_optstr_get_option(optstr, buf, &val, &sz);

		/* check also value (if the pattern is "foo=value") */
		if (rc == 0 && patvalsz > 0 &&
		    (patvalsz != sz || strncmp(patval, val, sz) != 0))
			rc = 1;

		switch (rc) {
		case 0:		/* found */
			match = no == 0 ? 1 : 0;
			break;
		case 1:		/* not found */
			match = no == 1 ? 1 : 0;
			break;
		default:	/* parse error */
			match = 0;
			break;
		}

	}

	free(buf);
	return match;
}

Project: util-linux
File: optstr.c

int mnt_optstr_get_options(const char *optstr, char **subset,
			    const struct libmnt_optmap *map, int ignore)
{
	struct libmnt_optmap const *maps[1];
	struct ul_buffer buf = UL_INIT_BUFFER;
	char *name, *val, *str = (char *) optstr;
	size_t namesz, valsz;
	int rc = 0;

	if (!optstr || !subset)
		return -EINVAL;

	maps[0] = map;

	ul_buffer_set_chunksize(&buf, strlen(optstr)/2);

	while (!mnt_optstr_next_option(&str, &name, &namesz, &val, &valsz)) {
		const struct libmnt_optmap *ent;

		mnt_optmap_get_entry(maps, 1, name, namesz, &ent);

		if (!ent || !ent->id)
			continue;	/* ignore undefined options (comments) */

		if (ignore && (ent->mask & ignore))
			continue;

		/* ignore name=<value> if options map expects <name> only */
		if (valsz && mnt_optmap_entry_novalue(ent))
			continue;

		rc = __buffer_append_option(&buf, name, namesz, val, valsz);
		if (rc)
			break;
	}

	*subset  = rc ? NULL : ul_buffer_get_data(&buf, NULL, NULL);
	if (rc)
		ul_buffer_free_data(&buf);
	return rc;
}

Project: util-linux
File: context_umount.c

static int lookup_umount_fs_by_statfs(struct libmnt_context *cxt, const char *tgt)
{
	struct stat st;
	const char *type;

	assert(cxt);
	assert(cxt->fs);

	DBG(CXT, ul_debugobj(cxt, " lookup by statfs"));

	/*
	 * Let's try to avoid mountinfo usage at all to minimize performance
	 * degradation. Don't forget that kernel has to compose *whole*
	 * mountinfo about all mountpoints although we look for only one entry.
	 *
	 * All we need is fstype and to check if there is no userspace mount
	 * options for the target (e.g. helper=udisks to call /sbin/umount.udisks).
	 *
	 * So, let's use statfs() if possible (it's bad idea for --lazy/--force
	 * umounts as target is probably unreachable NFS, also for --detach-loop
	 * as this additionally needs to know the name of the loop device).
	 */
	if (mnt_context_is_restricted(cxt)
	    || *tgt != '/'
	    || (cxt->flags & MNT_FL_HELPER)
	    || mnt_context_mtab_writable(cxt)
	    || mnt_context_is_force(cxt)
	    || mnt_context_is_lazy(cxt)
	    || mnt_context_is_nocanonicalize(cxt)
	    || mnt_context_is_loopdel(cxt)
	    || mnt_stat_mountpoint(tgt, &st) != 0 || !S_ISDIR(st.st_mode)
	    || has_utab_entry(cxt, tgt))
		return 1; /* not found */

	type = mnt_fs_get_fstype(cxt->fs);
	if (!type) {
		struct statfs vfs;
		int fd;

		DBG(CXT, ul_debugobj(cxt, "  trying fstatfs()"));

		/* O_PATH avoids triggering automount points. */
		fd = open(tgt, O_PATH);
		if (fd >= 0) {
			if (fstatfs(fd, &vfs) == 0)
				type = mnt_statfs_get_fstype(&vfs);
			close(fd);
		}
		if (type) {
			int rc = mnt_fs_set_fstype(cxt->fs, type);
			if (rc)
				return rc;
		}
	}
	if (type) {
		DBG(CXT, ul_debugobj(cxt, "  umount: disabling mtab"));
		mnt_context_disable_mtab(cxt, TRUE);

		DBG(CXT, ul_debugobj(cxt,
			"  mountinfo unnecessary [type=%s]", type));
		return 0;
	}

	return 1; /* not found */
}

Project: util-linux
File: context_umount.c

static int exec_helper(struct libmnt_context *cxt)
{
	char *namespace = NULL;
	struct libmnt_ns *ns_tgt = mnt_context_get_target_ns(cxt);
	int rc;
	pid_t pid;

	assert(cxt);
	assert(cxt->fs);
	assert(cxt->helper);
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
	assert(cxt->helper_exec_status == 1);

	if (mnt_context_is_fake(cxt)) {
		DBG(CXT, ul_debugobj(cxt, "fake mode: does not execute helper"));
		cxt->helper_exec_status = rc = 0;
		return rc;
	}

	if (ns_tgt->fd != -1
	    && asprintf(&namespace, "/proc/%i/fd/%i",
			getpid(), ns_tgt->fd) == -1) {
		return -ENOMEM;
	}

	DBG_FLUSH;

	pid = fork();
	switch (pid) {
	case 0:
	{
		const char *args[12], *type;
		int i = 0;

		if (drop_permissions() != 0)
			_exit(EXIT_FAILURE);

		if (!mnt_context_switch_origin_ns(cxt))
			_exit(EXIT_FAILURE);

		type = mnt_fs_get_fstype(cxt->fs);

		args[i++] = cxt->helper;			/* 1 */
		args[i++] = mnt_fs_get_target(cxt->fs);		/* 2 */

		if (mnt_context_is_nomtab(cxt))
			args[i++] = "-n";			/* 3 */
		if (mnt_context_is_lazy(cxt))
			args[i++] = "-l";			/* 4 */
		if (mnt_context_is_force(cxt))
			args[i++] = "-f";			/* 5 */
		if (mnt_context_is_verbose(cxt))
			args[i++] = "-v";			/* 6 */
		if (mnt_context_is_rdonly_umount(cxt))
			args[i++] = "-r";			/* 7 */
		if (type
		    && strchr(type, '.')
		    && !endswith(cxt->helper, type)) {
			args[i++] = "-t";			/* 8 */
			args[i++] = type;			/* 9 */
		}
		if (namespace) {
			args[i++] = "-N";			/* 10 */
			args[i++] = namespace;			/* 11 */
		}

		args[i] = NULL;					/* 12 */
		for (i = 0; args[i]; i++)
			DBG(CXT, ul_debugobj(cxt, "argv[%d] = \"%s\"",
							i, args[i]));
		DBG_FLUSH;
		execv(cxt->helper, (char * const *) args);
		_exit(EXIT_FAILURE);
	}
	default:
	{
		int st;

		if (waitpid(pid, &st, 0) == (pid_t) -1) {
			cxt->helper_status = -1;
			rc = -errno;
		} else {
			cxt->helper_status = WIFEXITED(st) ? WEXITSTATUS(st) : -1;
			cxt->helper_exec_status = rc = 0;
		}
		DBG(CXT, ul_debugobj(cxt, "%s executed [status=%d, rc=%d%s]",
				cxt->helper,
				cxt->helper_status, rc,
				rc ? " waitpid failed" : ""));
		break;
	}

	case -1:
		cxt->helper_exec_status = rc = -errno;
		DBG(CXT, ul_debugobj(cxt, "fork() failed"));
		break;
	}

	free(namespace);
	return rc;
}

Project: util-linux
File: optstr.c

static int test_dedup(struct libmnt_test *ts, int argc, char *argv[])
{
	const char *name;
	char *optstr;
	int rc;

	if (argc < 3)
		return -EINVAL;
	optstr = xstrdup(argv[1]);
	name = argv[2];

	rc = mnt_optstr_deduplicate_option(&optstr, name);
	if (!rc)
		printf("result: >%s<\n", optstr);
	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

static int has_utab_entry(struct libmnt_context *cxt, const char *target)
{
	struct libmnt_cache *cache = NULL;
	struct libmnt_fs *fs;
	struct libmnt_iter itr;
	char *cn = NULL;
	int rc = 0;

	assert(cxt);

	if (!cxt->utab) {
		const char *path = mnt_get_utab_path();

		if (!path || is_file_empty(path))
			return 0;
		cxt->utab = mnt_new_table();
		if (!cxt->utab)
			return 0;
		cxt->utab->fmt = MNT_FMT_UTAB;
		if (mnt_table_parse_file(cxt->utab, path))
			return 0;
	}

	/* paths in utab are canonicalized */
	cache = mnt_context_get_cache(cxt);
	cn = mnt_resolve_path(target, cache);
	mnt_reset_iter(&itr, MNT_ITER_BACKWARD);

	while (mnt_table_next_fs(cxt->utab, &itr, &fs) == 0) {
		if (mnt_fs_streq_target(fs, cn)) {
			rc = 1;
			break;
		}
	}

	if (!cache)
		free(cn);
	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_fix_uid(char **optstr, char *value, size_t valsz, char **next)
{
	char *end;

	if (!optstr || !*optstr || !value || !valsz)
		return -EINVAL;

	DBG(CXT, ul_debug("fixing uid"));

	end = value + valsz;

	if (valsz == 7 && !strncmp(value, "useruid", 7) &&
	    (*(value + 7) == ',' || !*(value + 7)))
		return set_uint_value(optstr, getuid(), value, end, next);

	if (!isdigit(*value)) {
		uid_t id;
		int rc;
		char *p = strndup(value, valsz);
		if (!p)
			return -ENOMEM;
		rc = mnt_get_uid(p, &id);
		free(p);

		if (!rc)
			return set_uint_value(optstr, id, value, end, next);
	}

	if (next) {
		/* no change, let's keep the original value */
		*next = value + valsz;
		if (**next == ',')
			(*next)++;
	}

	return 0;
}

Project: util-linux
File: context_umount.c

int mnt_context_do_umount(struct libmnt_context *cxt)
{
	int rc;
	struct libmnt_ns *ns_old;

	assert(cxt);
	assert(cxt->fs);
	assert(cxt->helper_exec_status == 1);
	assert(cxt->syscall_status == 1);
	assert((cxt->flags & MNT_FL_PREPARED));
	assert((cxt->action == MNT_ACT_UMOUNT));
	assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));

	ns_old = mnt_context_switch_target_ns(cxt);
	if (!ns_old)
		return -MNT_ERR_NAMESPACE;

	rc = do_umount(cxt);
	if (rc)
		goto end;

	if (mnt_context_get_status(cxt) && !mnt_context_is_fake(cxt)) {
		/*
		 * Umounted, do some post-umount operations
		 *	- remove loopdev
		 *	- refresh in-memory mtab stuff if remount rather than
		 *	  umount has been performed
		 */
		if (mnt_context_is_loopdel(cxt)
		    && !(cxt->mountflags & MS_REMOUNT))
			rc = mnt_context_delete_loopdev(cxt);

		if (!mnt_context_is_nomtab(cxt)
		    && mnt_context_get_status(cxt)
		    && !cxt->helper
		    && mnt_context_is_rdonly_umount(cxt)
		    && (cxt->mountflags & MS_REMOUNT)) {

			/* use "remount" instead of "umount" in /etc/mtab */
			if (!rc && cxt->update && mnt_context_mtab_writable(cxt))
				rc = mnt_update_set_fs(cxt->update,
						       cxt->mountflags, NULL, cxt->fs);
		}
	}
end:
	if (!mnt_context_switch_ns(cxt, ns_old))
		return -MNT_ERR_NAMESPACE;

	return rc;
}

Project: util-linux
File: optstr.c

static int set_uint_value(char **optstr, unsigned int num,
			char *begin, char *end, char **next)
{
	char buf[40];
	snprintf(buf, sizeof(buf), "%u", num);

	mnt_optstr_remove_option_at(optstr, begin, end);
	return insert_value(optstr, begin, buf, next);
}

Project: util-linux
File: optstr.c

static int test_fix(struct libmnt_test *ts, int argc, char *argv[])
{
	char *optstr;
	int rc = 0;
	char *name, *val, *next;
	size_t valsz, namesz;

	if (argc < 2)
		return -EINVAL;

	next = optstr = xstrdup(argv[1]);

	printf("optstr: %s\n", optstr);

	while (!mnt_optstr_next_option(&next, &name, &namesz, &val, &valsz)) {

		if (!strncmp(name, "uid", 3))
			rc = mnt_optstr_fix_uid(&optstr, val, valsz, &next);
		else if (!strncmp(name, "gid", 3))
			rc = mnt_optstr_fix_gid(&optstr, val, valsz, &next);
		else if (!strncmp(name, "context", 7))
			rc = mnt_optstr_fix_secontext(&optstr, val, valsz, &next);
		if (rc)
			break;
	}
	if (rc)
		rc = mnt_optstr_fix_user(&optstr);

	printf("fixed:  %s\n", optstr);

	free(optstr);
	return rc;

}

Project: util-linux
File: optstr.c

int mnt_optstr_get_flags(const char *optstr, unsigned long *flags,
		const struct libmnt_optmap *map)
{
	struct libmnt_optmap const *maps[2];
	char *name, *str = (char *) optstr;
	size_t namesz = 0, valsz = 0;
	int nmaps = 0;

	if (!optstr || !flags || !map)
		return -EINVAL;

	maps[nmaps++] = map;

	if (map == mnt_get_builtin_optmap(MNT_LINUX_MAP))
		/*
		 * Add userspace map -- the "user" is interpreted as
		 *                      MS_NO{EXEC,SUID,DEV}.
		 */
		maps[nmaps++] = mnt_get_builtin_optmap(MNT_USERSPACE_MAP);

	while(!mnt_optstr_next_option(&str, &name, &namesz, NULL, &valsz)) {
		const struct libmnt_optmap *ent;
		const struct libmnt_optmap *m;

		m = mnt_optmap_get_entry(maps, nmaps, name, namesz, &ent);
		if (!m || !ent || !ent->id)
			continue;

		/* ignore name=<value> if options map expects <name> only */
		if (valsz && mnt_optmap_entry_novalue(ent))
			continue;

		if (m == map) {				/* requested map */
			if (ent->mask & MNT_INVERT)
				*flags &= ~ent->id;
			else
				*flags |= ent->id;

		} else if (nmaps == 2 && m == maps[1] && valsz == 0) {
			/*
			 * Special case -- translate "user" (but no user=) to
			 * MS_ options
			 */
			if (ent->mask & MNT_INVERT)
				continue;
			if (ent->id & (MNT_MS_OWNER | MNT_MS_GROUP))
				*flags |= MS_OWNERSECURE;
			else if (ent->id & (MNT_MS_USER | MNT_MS_USERS))
				*flags |= MS_SECURE;
		}
	}

	return 0;
}

Project: util-linux
File: context_umount.c

static int __mtab_find_umount_fs(struct libmnt_context *cxt,
			    const char *tgt,
			    struct libmnt_fs **pfs)
{
	int rc;
	struct libmnt_ns *ns_old;
	struct libmnt_table *mtab = NULL;
	struct libmnt_fs *fs;
	char *loopdev = NULL;

	assert(cxt);
	assert(tgt);
	assert(pfs);

	*pfs = NULL;
	DBG(CXT, ul_debugobj(cxt, " search %s in mountinfo", tgt));

	/*
	 * The mount table may be huge, and on systems with utab we have to
	 * merge userspace mount options into /proc/self/mountinfo. This all is
	 * expensive. The tab filter can be used to filter out entries, then a mount
	 * table and utab are very tiny files.
	 *
	 * The filter uses mnt_fs_streq_{target,srcpath} function where all
	 * paths should be absolute and canonicalized. This is done within
	 * mnt_context_get_mtab_for_target() where LABEL, UUID or symlinks are
	 * canonicalized. If --no-canonicalize is enabled than the target path
	 * is expected already canonical.
	 *
	 * Anyway it's better to read huge mount table than canonicalize target
	 * paths. It means we use the filter only if --no-canonicalize enabled.
	 *
	 * It also means that we have to read mount table from kernel
	 * (non-writable mtab).
	 */
	if (mnt_context_is_nocanonicalize(cxt) &&
	    !mnt_context_mtab_writable(cxt) && *tgt == '/')
		rc = mnt_context_get_mtab_for_target(cxt, &mtab, tgt);
	else
		rc = mnt_context_get_mtab(cxt, &mtab);

	if (rc) {
		DBG(CXT, ul_debugobj(cxt, "umount: failed to read mtab"));
		return rc;
	}

	if (mnt_table_get_nents(mtab) == 0) {
		DBG(CXT, ul_debugobj(cxt, "umount: mtab empty"));
		return 1;
	}

	ns_old = mnt_context_switch_target_ns(cxt);
	if (!ns_old)
		return -MNT_ERR_NAMESPACE;

try_loopdev:
	fs = mnt_table_find_target(mtab, tgt, MNT_ITER_BACKWARD);
	if (!fs && mnt_context_is_swapmatch(cxt)) {
		/*
		 * Maybe the option is source rather than target (sometimes
		 * people use e.g. "umount /dev/sda1")
		 */
		fs = mnt_table_find_source(mtab, tgt, MNT_ITER_BACKWARD);

		if (fs) {
			struct libmnt_fs *fs1 = mnt_table_find_target(mtab,
							mnt_fs_get_target(fs),
							MNT_ITER_BACKWARD);
			if (!fs1) {
				DBG(CXT, ul_debugobj(cxt, "mtab is broken?!?!"));
				rc = -EINVAL;
				goto err;
			}
			if (fs != fs1) {
				/* Something was stacked over `file' on the
				 * same mount point. */
				DBG(CXT, ul_debugobj(cxt,
						"umount: %s: %s is mounted "
						"over it on the same point",
						tgt, mnt_fs_get_source(fs1)));
				rc = -EINVAL;
				goto err;
			}
		}
	}

	if (!fs && !loopdev && mnt_context_is_swapmatch(cxt)) {
		/*
		 * Maybe the option is /path/file.img, try to convert to /dev/loopN
		 */
		struct stat st;

		if (mnt_stat_mountpoint(tgt, &st) == 0 && S_ISREG(st.st_mode)) {
			int count;
			struct libmnt_cache *cache = mnt_context_get_cache(cxt);
			const char *bf = cache ? mnt_resolve_path(tgt, cache) : tgt;

			count = loopdev_count_by_backing_file(bf, &loopdev);
			if (count == 1) {
				DBG(CXT, ul_debugobj(cxt,
					"umount: %s --> %s (retry)", tgt, loopdev));
				tgt = loopdev;
				goto try_loopdev;

			} else if (count > 1)
				DBG(CXT, ul_debugobj(cxt,
					"umount: warning: %s is associated "
					"with more than one loopdev", tgt));
		}
	}

	*pfs = fs;
	free(loopdev);
	if (!mnt_context_switch_ns(cxt, ns_old))
		return -MNT_ERR_NAMESPACE;

	DBG(CXT, ul_debugobj(cxt, "umount fs: %s", fs ? mnt_fs_get_target(fs) :
							"<not found>"));
	return fs ? 0 : 1;
err:
	free(loopdev);
	if (!mnt_context_switch_ns(cxt, ns_old))
		return -MNT_ERR_NAMESPACE;
	return rc;
}

Project: util-linux
File: optstr.c

static int test_apply(struct libmnt_test *ts, int argc, char *argv[])
{
	char *optstr;
	int rc, map;
	unsigned long flags;

	if (argc < 4)
		return -EINVAL;

	if (!strcmp(argv[1], "--user"))
		map = MNT_USERSPACE_MAP;
	else if (!strcmp(argv[1], "--linux"))
		map = MNT_LINUX_MAP;
	else {
		fprintf(stderr, "unknown option '%s'\n", argv[1]);
		return -EINVAL;
	}

	optstr = xstrdup(argv[2]);
	flags = strtoul(argv[3], NULL, 16);

	printf("flags:  0x%08lx\n", flags);

	rc = mnt_optstr_apply_flags(&optstr, flags, mnt_get_builtin_optmap(map));
	printf("optstr: %s\n", optstr);

	free(optstr);
	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_find_umount_fs(struct libmnt_context *cxt,
			       const char *tgt,
			       struct libmnt_fs **pfs)
{
	if (pfs)
		*pfs = NULL;

	if (!cxt || !tgt || !pfs)
		return -EINVAL;

	DBG(CXT, ul_debugobj(cxt, "umount: lookup FS for '%s'", tgt));

	if (!*tgt)
		return 1; /* empty string is not an error */

	/* In future this function should be extended to support for example
	 * fsinfo() (or another cheap way kernel will support), for now the
	 * default is expensive mountinfo/mtab.
	 */
	return __mtab_find_umount_fs(cxt, tgt, pfs);
}

Project: util-linux
File: context_umount.c

static int prepare_helper_from_options(struct libmnt_context *cxt,
				       const char *name)
{
	char *suffix = NULL;
	const char *opts;
	size_t valsz;
	int rc;

	if (mnt_context_is_nohelpers(cxt))
		return 0;

	opts = mnt_fs_get_user_options(cxt->fs);
	if (!opts)
		return 0;

	if (mnt_optstr_get_option(opts, name, &suffix, &valsz))
		return 0;

	suffix = strndup(suffix, valsz);
	if (!suffix)
		return -ENOMEM;

	DBG(CXT, ul_debugobj(cxt, "umount: umount.%s %s requested", suffix, name));

	rc = mnt_context_prepare_helper(cxt, "umount", suffix);
	free(suffix);

	return rc;
}

Project: util-linux
File: context_umount.c

static int is_fuse_usermount(struct libmnt_context *cxt, int *errsv)
{
	struct libmnt_ns *ns_old;
	const char *type = mnt_fs_get_fstype(cxt->fs);
	const char *optstr;
	uid_t uid, entry_uid;

	*errsv = 0;

	if (!type)
		return 0;

	if (strcmp(type, "fuse") != 0 &&
	    strcmp(type, "fuseblk") != 0 &&
	    strncmp(type, "fuse.", 5) != 0 &&
	    strncmp(type, "fuseblk.", 8) != 0)
		return 0;

	/* get user_id= from mount table */
	optstr = mnt_fs_get_fs_options(cxt->fs);
	if (!optstr)
		return 0;
	if (mnt_optstr_get_uid(optstr, "user_id", &entry_uid) != 0)
		return 0;

	/* get current user */
	ns_old = mnt_context_switch_origin_ns(cxt);
	if (!ns_old) {
		*errsv = -MNT_ERR_NAMESPACE;
		return 0;
	}

	uid = getuid();

	if (!mnt_context_switch_ns(cxt, ns_old)) {
		*errsv = -MNT_ERR_NAMESPACE;
		return 0;
	}

	return uid == entry_uid;
}

Project: util-linux
File: optstr.c

int mnt_optstr_fix_secontext(char **optstr __attribute__ ((__unused__)),
			     char *value   __attribute__ ((__unused__)),
			     size_t valsz  __attribute__ ((__unused__)),
			     char **next   __attribute__ ((__unused__)))
{
	return 0;
}

Project: util-linux
File: optstr.c

int mnt_optstr_get_uid(const char *optstr, const char *name, uid_t *uid)
{
	char *value = NULL;
	size_t valsz = 0;
	char buf[sizeof(stringify_value(UINT64_MAX))];
	int rc;
	uint64_t num;

	assert(optstr);
	assert(name);
	assert(uid);

	rc = mnt_optstr_get_option(optstr, name, &value, &valsz);
	if (rc != 0)
		goto fail;

	if (valsz > sizeof(buf) - 1) {
		rc = -ERANGE;
		goto fail;
	}
	mem2strcpy(buf, value, valsz, sizeof(buf));

	rc = ul_strtou64(buf, &num, 10);
	if (rc != 0)
		goto fail;
	if (num > ULONG_MAX || (uid_t) num != num) {
		rc = -ERANGE;
		goto fail;
	}
	*uid = (uid_t) num;

	return 0;
fail:
	DBG(UTILS, ul_debug("failed to convert '%s'= to number [rc=%d]", name, rc));
	return rc;
}

Project: util-linux
File: context_umount.c

int mnt_context_next_umount(struct libmnt_context *cxt,
			   struct libmnt_iter *itr,
			   struct libmnt_fs **fs,
			   int *mntrc,
			   int *ignored)
{
	struct libmnt_table *mtab;
	const char *tgt;
	int rc;

	if (ignored)
		*ignored = 0;
	if (mntrc)
		*mntrc = 0;

	if (!cxt || !fs || !itr)
		return -EINVAL;

	rc = mnt_context_get_mtab(cxt, &mtab);
	cxt->mtab = NULL;		/* do not reset mtab */
	mnt_reset_context(cxt);

	if (rc)
		return rc;

	cxt->mtab = mtab;

	do {
		rc = mnt_table_next_fs(mtab, itr, fs);
		if (rc != 0)
			return rc;	/* no more filesystems (or error) */

		tgt = mnt_fs_get_target(*fs);
	} while (!tgt);

	DBG(CXT, ul_debugobj(cxt, "next-umount: trying %s [fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]", tgt,
				 mnt_fs_get_fstype(*fs), cxt->fstype_pattern, mnt_fs_get_options(*fs), cxt->optstr_pattern));

	/* ignore filesystems which don't match options patterns */
	if ((cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
					cxt->fstype_pattern)) ||

	/* ignore filesystems which don't match type patterns */
	   (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
					cxt->optstr_pattern))) {
		if (ignored)
			*ignored = 1;

		DBG(CXT, ul_debugobj(cxt, "next-umount: not-match"));
		return 0;
	}

	rc = mnt_context_set_fs(cxt, *fs);
	if (rc)
		return rc;
	rc = mnt_context_umount(cxt);
	if (mntrc)
		*mntrc = rc;
	return 0;
}

Project: util-linux
File: optstr.c

static int test_get(struct libmnt_test *ts, int argc, char *argv[])
{
	char *optstr;
	const char *name;
	char *val = NULL;
	size_t sz = 0;
	int rc;

	if (argc < 2)
		return -EINVAL;
	optstr = argv[1];
	name = argv[2];

	rc = mnt_optstr_get_option(optstr, name, &val, &sz);
	if (rc == 0) {
		printf("found; name: %s", name);
		if (sz) {
			printf(", argument: size=%zd data=", sz);
			if (fwrite(val, 1, sz, stdout) != sz)
				return -1;
		}
		printf("\n");
	} else if (rc == 1)
		printf("%s: not found\n", name);
	else
		printf("parse error: %s\n", optstr);
	return rc;
}

Project: util-linux
File: optstr.c

int mnt_optstr_prepend_option(char **optstr, const char *name, const char *value)
{
	struct ul_buffer buf = UL_INIT_BUFFER;
	size_t nsz, vsz, osz;
	int rc;

	if (!optstr)
		return -EINVAL;
	if (!name || !*name)
		return 0;

	nsz = strlen(name);
	osz = *optstr ? strlen(*optstr) : 0;
	vsz = value ? strlen(value) : 0;

	ul_buffer_set_chunksize(&buf, osz + nsz + vsz + 3);   /* to call realloc() only once */

	rc = __buffer_append_option(&buf, name, nsz, value, vsz);
	if (*optstr && !rc) {
		rc = ul_buffer_append_data(&buf, ",", 1);
		if (!rc)
			rc = ul_buffer_append_data(&buf, *optstr, osz);
		free(*optstr);
	}

	*optstr = ul_buffer_get_data(&buf, NULL, NULL);
	return rc;
}

Project: util-linux
File: context_umount.c

static int lookup_umount_fs(struct libmnt_context *cxt)
{
	const char *tgt;
	int rc = 0;

	assert(cxt);
	assert(cxt->fs);

	DBG(CXT, ul_debugobj(cxt, "umount: lookup FS"));

	tgt = mnt_fs_get_target(cxt->fs);
	if (!tgt) {
		DBG(CXT, ul_debugobj(cxt, " undefined target"));
		return -EINVAL;
	}

	/* try get fs type by statfs() */
	rc = lookup_umount_fs_by_statfs(cxt, tgt);
	if (rc <= 0)
		return rc;

	/* get complete fs from fs entry from mountinfo */
	rc = lookup_umount_fs_by_mountinfo(cxt, tgt);
	if (rc <= 0)
		return rc;

	DBG(CXT, ul_debugobj(cxt, " cannot find '%s'", tgt));
	return 0;	/* this is correct! */
}

Project: util-linux
File: optstr.c

int mnt_optstr_append_option(char **optstr, const char *name, const char *value)
{
	struct ul_buffer buf = UL_INIT_BUFFER;
	int rc;
	size_t nsz, vsz, osz;

	if (!optstr)
		return -EINVAL;
	if (!name || !*name)
		return 0;

	nsz = strlen(name);
	osz = *optstr ? strlen(*optstr) : 0;
	vsz = value ? strlen(value) : 0;

	ul_buffer_refer_string(&buf, *optstr);
	ul_buffer_set_chunksize(&buf, osz + nsz + vsz + 3);	/* to call realloc() only once */

	rc = __buffer_append_option(&buf, name, nsz, value, vsz);

	*optstr = ul_buffer_get_data(&buf, NULL, NULL);
	return rc;
}