Commit b420b7b7 authored Sep 18, 2018 by Andreas Gruenbacher Committed by Greg Kroah-Hartman Oct 10, 2018

sysfs: Do not return POSIX ACL xattrs via listxattr



commit ffc4c922 upstream.

Commit 786534b9 introduced a regression that caused listxattr to
return the POSIX ACL attribute names even though sysfs doesn't support
POSIX ACLs.  This happens because simple_xattr_list checks for NULL
i_acl / i_default_acl, but inode_init_always initializes those fields
to ACL_NOT_CACHED ((void *)-1).  For example:
    $ getfattr -m- -d /sys
    /sys: system.posix_acl_access: Operation not supported
    /sys: system.posix_acl_default: Operation not supported
Fix this in simple_xattr_list by checking if the filesystem supports POSIX ACLs.

Fixes: 786534b9 ("tmpfs: listxattr should include POSIX ACL xattrs")
Reported-by: Marc Aurèle La France <tsi@tuyoix.net>
Tested-by: Marc Aurèle La France <tsi@tuyoix.net>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent fa7d75f6

fs/xattr.c

+13 −11

Original line number	Original line	Diff line number	Diff line
	@@ -951,6 +951,7 @@ ssize_t simple_xattr_list(struct inode inode, struct simple_xattrs xattrs,
	int err = 0;		int err = 0;

	#ifdef CONFIG_FS_POSIX_ACL		#ifdef CONFIG_FS_POSIX_ACL
			if (IS_POSIXACL(inode)) {
	if (inode->i_acl) {		if (inode->i_acl) {
	err = xattr_list_one(&buffer, &remaining_size,		err = xattr_list_one(&buffer, &remaining_size,
	XATTR_NAME_POSIX_ACL_ACCESS);		XATTR_NAME_POSIX_ACL_ACCESS);
	@@ -963,6 +964,7 @@ ssize_t simple_xattr_list(struct inode inode, struct simple_xattrs xattrs,
	if (err)		if (err)
	return err;		return err;
	}		}
			}
	#endif		#endif

	spin_lock(&xattrs->lock);		spin_lock(&xattrs->lock);