Bug 1869245 (CVE-2019-14562)

Summary:	CVE-2019-14562 edk2: DxeImageVerificationHandler integer overflow leads to endless loop
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	berrange, crobinso, kraxel, lersek, pbonzini, virt-maint, virt-maint, xuwei
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1869247, 1869246, 1870390, 1910519
Bug Blocks:	1869249

Description Dhananjay Arunesh 2020-08-17 11:18:19 UTC

There is an integer overflow vulnerability in the DxeImageVerificationHandler(..) function when parsing the PE files attribute certificate table. In cases where WinCertificate->dwLength is sufficiently large, it's possible to overflow Offset back to 0 causing an endless loop.

References:
https://bugzilla.tianocore.org/show_bug.cgi?id=2215

Comment 1 Laszlo Ersek 2020-08-17 18:18:10 UTC

Note that the upstream bug report at <https://bugzilla.tianocore.org/show_bug.cgi?id=2215#c0> is seriously under-specified. In the discussion linked at <https://bugzilla.tianocore.org/show_bug.cgi?id=2215#c5>, we're now trying to figure out what the original bug reporter had in mind exactly.

Comment 2 Todd Cullum 2020-08-19 23:31:42 UTC

Flaw summary:

DxeImageVerificationHandler() in SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c, provides verification service for signed PE/COFF images. This flaw is an unsigned integer wrap bug where the OffSet UINT32 variable, which is used in a for loop exit condition, could continuously wrap to 0 or another UINT32 lower than SecDataDir->VirtualAddress and cause an infinite loop, which could result in denial of service. The patch:

1) Checks that Offset >= SecDataDir->VirtualAddress, and if not, exits the loop
2) #includes Library/SafeIntLib.h and uses SafeUint32Add() to prevent unsigned integer wrapping

These steps are important because DxeImageVerificationHandler() may process untrusted PE/COFF inputs [1]. To exploit this flaw, an attacker would need to supply a specially crafted input file locally.

1. https://github.com/leadsama/edk2/blob/ba21bb0e0f0bf0fe977ccad91a40b79fd2b7320c/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c#L1599

Comment 6 Todd Cullum 2020-08-19 23:43:39 UTC

Acknowledgments:

Name: Laszlo Ersek
Upstream: Jian J. Wang

Comment 8 Laszlo Ersek 2020-09-01 08:55:00 UTC

Reproducer described in <https://bugzilla.tianocore.org/show_bug.cgi?id=2215#c6>.

Comment 9 Laszlo Ersek 2020-09-02 10:35:16 UTC

Upstream commit range: 751355992635..0b143fa43e92.