Bug 1852487 (CVE-2020-0093)

Summary:	CVE-2020-0093 libexif: out of bounds read due to a missing bounds check in exif_data_save_data_entry function in exif-data.c
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	ajax, caillon+fedoraproject, gnome-sig, john.j5live, rdieter, rhbugs, rhughes, rstrode, sandmann, thomasj, yselkowi
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libexif 0.6.22	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-09-29 22:02:03 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1852489, 1853107, 1853108
Bug Blocks:	1852493

Description Guilherme de Almeida Suckevicz 2020-06-30 14:22:07 UTC

In exif_data_save_data_entry of exif-data.c, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is needed for exploitation.

References:
https://source.android.com/security/bulletin/2020-05-01
https://android.googlesource.com/platform/external/libexif/+/0335ffc17f9b9a4831c242bb08ea92f605fde7a6

Comment 1 Guilherme de Almeida Suckevicz 2020-06-30 14:22:38 UTC

Created libexif tracking bugs for this issue:

Affects: fedora-all [bug 1852489]

Comment 2 Todd Cullum 2020-07-01 23:16:32 UTC

Technical Summary:

In exif_data_save_data_entry(), data is copied using memcpy(), from e->data, using a size computation that relies on the standard format size multiplied by the number of components. In the case where the actual entry size (e->size) was smaller than this computed value, there could be a buffer overread that would leak out-of-bounds data into an EXIF entry. The patch ensures that the length passed to memcpy() cannot exceed the actual entry size.

Comment 4 Todd Cullum 2020-07-06 17:32:00 UTC

FYI the upstream patch is identical to the Android fork patch in this case: https://github.com/libexif/libexif/commit/5ae5973bed1947f4d447dc80b76d5cefadd90133 .

Comment 5 errata-xmlrpc 2020-09-29 20:50:50 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4040 https://access.redhat.com/errata/RHSA-2020:4040

Comment 6 Product Security DevOps Team 2020-09-29 22:02:03 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-2020-0093

Comment 7 errata-xmlrpc 2020-11-04 03:43:24 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4766 https://access.redhat.com/errata/RHSA-2020:4766