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FreeBSD: VID-A9C6E9BE-61FB-11EB-B87A-901B0EF719AB (CVE-2020-25578): FreeBSD -- Uninitialized kernel stack leaks in several file systems

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FreeBSD: VID-A9C6E9BE-61FB-11EB-B87A-901B0EF719AB (CVE-2020-25578): FreeBSD -- Uninitialized kernel stack leaks in several file systems

Severity
5
CVSS
(AV:N/AC:L/Au:N/C:P/I:N/A:N)
Published
01/29/2021
Created
02/02/2021
Added
01/30/2021
Modified
04/05/2021

Description

Details for this vulnerability have not been published by NIST at this point. Descriptions from software vendor advisories for this issue are provided below.

From VID-A9C6E9BE-61FB-11EB-B87A-901B0EF719AB:

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.

Additionally, msdosfs(5) was failing to zero-fill a pair of padding

fields in the dirent structure, resulting in a leak of three

uninitialized bytes.

Impact:

Kernel stack disclosures may leak sensitive information which could

be used to compromise the security of the system.

Solution(s)

  • freebsd-upgrade-base-11_4-release-p7
  • freebsd-upgrade-base-12_1-release-p13
  • freebsd-upgrade-base-12_2-release-p3

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