ASA-2019-00404 – FreeBSD: Kernel stack disclosure in UFS/FFS


Allele Security Alert

ASA-2019-00404

Identifier(s)

ASA-2019-00404, CVE-2019-5601, FreeBSD-SA-19:10.ufs

Title

Kernel stack disclosure in UFS/FFS

Vendor(s)

The FreeBSD Project

Product(s)

FreeBSD

Affected version(s)

All supported versions of FreeBSD

Fixed version(s)

2019-05-10 23:45:16 UTC (stable/12, 12.0-STABLE)
2019-07-02 00:02:16 UTC (releng/12.0, 12.0-RELEASE-p7)
2019-05-10 23:46:42 UTC (stable/11, 11.2-STABLE)
2019-07-02 00:02:16 UTC (releng/11.2, 11.2-RELEASE-p11)

Proof of concept

Unknown

Description

The Berkeley Fast File System (FFS) is an implementation of the UNIX File System (UFS) filesystem used by FreeBSD.

A bug causes up to three bytes of kernel stack memory to be written to disk as uninitialized directory entry padding. This data can be viewed by any user with read access to the directory. Additionally, a malicious user with write access to a directory can cause up to 254 bytes of kernel stack memory to be exposed.

Some amount of the kernel stack is disclosed and written out to the filesystem.

Technical details

Unknown

Workaround

Unknown

Credits

David G. Lawrence

Reference(s)

Kernel stack disclosure in UFS/FFS
https://www.freebsd.org/security/advisories/FreeBSD-SA-19:10.ufs.asc

[base] Revision 347474
https://svnweb.freebsd.org/base?view=revision&revision=r347474

[base] Revision 349623
https://svnweb.freebsd.org/base?view=revision&revision=r349623

[base] Revision 347475
https://svnweb.freebsd.org/base?view=revision&revision=r347475

CVE-2019-5601
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5601

CVE-2019-5601
https://nvd.nist.gov/vuln/detail/CVE-2019-5601

If there is any error in this alert or you wish a comprehensive analysis, let us know.

Last modified: July 3, 2019

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