Bug 1861883

Summary:	pointer aliasing/alignment issue can cause performance issues or crashes
Product:	Red Hat Enterprise Linux 8	Reporter:	Todd Cullum <tcullum>
Component:	libvncserver	Assignee:	Jonas Ådahl <jadahl>
Status:	CLOSED WONTFIX	QA Contact:	Desktop QE <desktop-qa-list>
Severity:	low	Docs Contact:
Priority:	unspecified
Version:	8.3
Target Milestone:	rc
Target Release:	8.0
Hardware:	arm
OS:	Unspecified
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Last Closed:	2022-01-29 07:27:05 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Todd Cullum 2020-07-29 19:29:43 UTC

Description of problem:
Accessing byte-aligned data through uint32_t pointers can cause crashes
on some platforms or reduce the performance.

Version-Release number of selected component (if applicable):
libvncserver-0.9.11-15.el8_2.1

How reproducible:
I have not been able to reproduce this but it is acknowledged upstream here: https://github.com/LibVNC/libvncserver/commit/23e5cbe6b090d7f22982aee909a6a618174d3c2d


Actual results:
Can cause slow downs or crashes on ARM.

Expected results:
SetFormatAndEncodings() behaves normally without performance issues or crashes.

Additional info:
Note that this bug was originally picked up as a CVE/security issue. However, during analysis and after speaking with upstream developer Toby Junghans, we determined there is no security risk and this is a trivial reliability bug at most. I am filing this to let the maintainer know about the issue. I checked the code shipped in RHEL8 and found that the bug exists via code examination.

Comment 3 RHEL Program Management 2022-01-29 07:27:05 UTC

After evaluating this issue, there are no plans to address it further or fix it in an upcoming release.  Therefore, it is being closed.  If plans change such that this issue will be fixed in an upcoming release, then the bug can be reopened.