Bug 1678685 (CVE-2019-8912) - CVE-2019-8912 kernel: af_alg_release() in crypto/af_alg.c neglects to set a NULL value for a certain structure member, which leads to a use-after-free in sockfs_setattr
Summary: CVE-2019-8912 kernel: af_alg_release() in crypto/af_alg.c neglects to set a N...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2019-8912
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1678686 1679432 1679433 1679434 1679435 1679436 1679437 1679438 1679439 1679440 1679441 1679442 1679444 1679445 1679446 1679447 1679448 1679449 1679450 1679451 1679452 1679524
Blocks: 1678692
TreeView+ depends on / blocked
 
Reported: 2019-02-19 11:42 UTC by msiddiqu
Modified: 2021-02-16 22:21 UTC (History)
39 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
In the Linux kernel af_alg_release() in crypto/af_alg.c neglects to set a NULL value for a certain structure member, which leads to a use-after-free (UAF) in sockfs_setattr. A local attacker can use this flaw to escalate privileges and take control of the system.
Clone Of:
Environment:
Last Closed: 2020-01-21 20:09:30 UTC
Embargoed:

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2020:0174 0 None None None 2020-01-21 15:49:35 UTC

Description msiddiqu 2019-02-19 11:42:07 UTC 
In the Linux kernel af_alg_release() in crypto/af_alg.c neglects to set a NULL value for a certain structure member, which leads to a use-after-free (UAF) in sockfs_setattr.

A local attacker can use this flaw to escalate privileges and take control of the system.  Other vendors have considered this a 'network' accessible attack, this claim is unsubstantiated at this time. 

Note: The attack vector that allowed the use-after-free mentioned in the original report is not introduced in the Red Hat Enterprise Linux 7, 6 and 5 versions of the kernel.  

References:

http://patchwork.ozlabs.org/patch/1042902/

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9060cb719e61b685ec0102574e10337fa5f445ea
Comment 1 msiddiqu 2019-02-19 11:42:20 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1678686]
Comment 11 errata-xmlrpc 2020-01-21 15:49:32 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:0174 https://access.redhat.com/errata/RHSA-2020:0174
Comment 12 Product Security DevOps Team 2020-01-21 20:09:30 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2019-8912
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