Bug 1846964 (CVE-2020-10774)

Summary: CVE-2020-10774 kernel: possibility of memory disclosure when reading the file /proc/sys/kernel/rh_features
Product: [Other] Security Response Reporter: Alex <allarkin>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: acaringi, aquini, bhu, blc, bmasney, brdeoliv, dhoward, dvlasenk, esammons, fhrbata, hkrzesin, iboverma, jlelli, jross, jshortt, jstancek, kcarcia, kernel-mgr, lgoncalv, matt, mcressma, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: kernel-4.18.0-193.el8 Doc Type: If docs needed, set a value
Doc Text:
A flaw memory disclosure flaw was found in the Linux kernel’s sysctl subsystem in reading the /proc/sys/kernel/rh_features file. This flaw allows a local user to read uninitialized values from the kernel memory. The highest threat from this vulnerability is to confidentiality.
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-11-04 02:25:49 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1843064, 1846968, 1847952    
Bug Blocks: 1843480    

Description Alex 2020-06-15 09:36:03 UTC
The /proc/sys/kernel/rh_features file is readable by unprivileged users and if no tracked feature is used on the system (that is by default), it copies a chunk of uninitialized memory to the user space. Means that reading of the file /proc/sys/kernel/rh_features by unprivileged user can lead to kernel memory disclosure, but user cannot control the size and location of the memory being read (usually empty or nothing, so in most cases no memory disclosure). There's no buffer overflow or availability impact, so only possibility of confidentiality impact.

It's in RHEL 8 only code (not upstream) and was introduced in RHEL 8.2 by kernel commit b42078ac845a ("[kernel] rh_features: move rh_features
entry to sys/kernel").

Comment 5 Petr Matousek 2020-06-17 12:22:01 UTC

This issue is rated as having Low impact because of the limited and random (non-controllable by attacker) memory disclosure.

Comment 6 Petr Matousek 2020-06-17 12:22:07 UTC

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 8 errata-xmlrpc 2020-11-04 00:51:18 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4431 https://access.redhat.com/errata/RHSA-2020:4431

Comment 9 errata-xmlrpc 2020-11-04 02:24:03 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4609 https://access.redhat.com/errata/RHSA-2020:4609

Comment 10 Product Security DevOps Team 2020-11-04 02:25:49 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):