On 29/01/2021 03:28, FreeBSD Security Advisories wrote:
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FreeBSD-SA-21:01.fsdisclosure                               Security Advisory
                                                           The FreeBSD Project

Topic:          Uninitialized kernel stack leaks in several file systems

Category:       core
Module:         fs
Announced:      2021-01-29
Credits:        Syed Faraz Abrar
Affects:        All supported versions of FreeBSD.
Corrected:      2021-01-06 14:58:41 UTC (stable/12, 12.2-STABLE)
                 2021-01-29 01:20:59 UTC (releng/12.2, 12.2-RELEASE-p3)
                 2021-01-29 01:06:09 UTC (releng/12.1, 12.1-RELEASE-p13)
                 2021-01-18 19:16:24 UTC (stable/11, 11.4-STABLE)
                 2021-01-29 00:20:09 UTC (releng/11.4, 11.4-RELEASE-p7)
CVE Name:       CVE-2020-25578, CVE-2020-25579

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:https://security.FreeBSD.org/>.

I.   Background

The FreeBSD kernel exports file system directory entries to userspace
using the generic "dirent" structure.  Individual file systems implement
VOP_READDIR to convert from the file system's internal directory entry
layout to the generic form.  dirent structures can be fetched from
userspace using the getdirentries(2) system call.

II.  Problem Description

Several file systems were not properly initializing the d_off field of
the dirent structures returned by VOP_READDIR.  In particular, tmpfs(5),
smbfs(5), autofs(5) and mqueuefs(5) were failing to do so.  As a result,
eight uninitialized kernel stack bytes may be leaked to userspace by
these file systems.  This problem is not present in FreeBSD 11.

There is a Corrected in: stable/11, 11.4-STABLE and releng/11.4, 11.4-RELEASE-p7, but later is a statement "This problem is not present in FreeBSD 11". What is true? Is it fixed in newer patchlevel of FreeBSD 11.4 or it was not present in 11.x at all?

Kind regards
Miroslav Lachman
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