We have several virtual xattrs in cephfs which return various values as strings. xattrs don't necessarily return strings however, so we need to include the terminating NULL byte in the length when we return the length. Furthermore, the getxattr manpage says that we should return -ERANGE if the buffer is too small to hold the resulting value. Let's start doing that here as well. URL: https://bugzilla.redhat.com/show_bug.cgi?id=1717454 Reported-by: Tomas Petr &lt;tpetr(a)redhat.com&gt; Signed-off-by: Jeff Layton &lt;jlayton(a)kernel.org&gt; --- fs/ceph/xattr.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 6621d27e64f5..57f1bd83c21c 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -803,8 +803,14 @@ ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value, if (err) return err; err = -ENODATA; - if (!(vxattr->exists_cb && !vxattr->exists_cb(ci))) - err = vxattr->getxattr_cb(ci, value, size); + if (!(vxattr->exists_cb && !vxattr->exists_cb(ci))) { + /* Make sure result will fit in buffer */ + if (size > 0) { + if (size < vxattr->getxattr_cb(ci, NULL, 0) + 1) + return -ERANGE; + } + err = vxattr->getxattr_cb(ci, value, size) + 1;