sysfs: Do not return POSIX ACL xattrs via listxattr

Commit 786534b92f 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: 786534b92f ("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>
This commit is contained in:
Andreas Gruenbacher 2018-09-18 00:36:36 -04:00 committed by Al Viro
parent 5b394b2ddf
commit ffc4c92227

View File

@ -948,6 +948,7 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
int err = 0;
#ifdef CONFIG_FS_POSIX_ACL
if (IS_POSIXACL(inode)) {
if (inode->i_acl) {
err = xattr_list_one(&buffer, &remaining_size,
XATTR_NAME_POSIX_ACL_ACCESS);
@ -960,6 +961,7 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
if (err)
return err;
}
}
#endif
spin_lock(&xattrs->lock);