Bug 1462172 (CVE-2017-9605)

Summary:	CVE-2017-9605 kernel: Uninitialized kernel memory leak in vmw_gb_surface_define_ioctl function
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	agordeev, aquini, bhu, dhoward, esammons, fhrbata, gansalmon, hwkernel-mgr, iboverma, ichavero, itamar, jforbes, jkacur, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, slawomir, vdronov, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	The vmw_gb_surface_define_ioctl function (accessible via DRM_IOCTL_VMW_GB_SURFACE_CREATE) in drivers/gpu/drm/vmwgfx/vmwgfx_surface.c in the Linux kernel through 4.11.4 defines a backup_handle variable but does not give it an initial value. If one attempts to create a GB surface, with a previously allocated DMA buffer to be used as a backup buffer, the backup_handle variable does not get written to and is then later returned to user space, allowing local users to obtain sensitive information from uninitialized kernel memory via a crafted ioctl call.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-06-19 15:40:47 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:	1462173, 1462817
Bug Blocks:	1462174

Description Adam Mariš 2017-06-16 11:27:48 UTC

The vmw_gb_surface_define_ioctl function (accessible via DRM_IOCTL_VMW_GB_SURFACE_CREATE) in drivers/gpu/drm/vmwgfx/vmwgfx_surface.c in the Linux kernel through 4.11.4 defines a backup_handle variable but does not give it an initial value. If one attempts to create a GB surface, with a previously allocated DMA buffer to be used as a backup buffer, the backup_handle variable does not get written to and is then later returned to user space, allowing local users to obtain sensitive information from uninitialized kernel memory via a crafted ioctl call.

Discussion:

http://seclists.org/oss-sec/2017/q2/459

CVE-ID assignment:

http://seclists.org/oss-sec/2017/q2/468

Upstream patch:

https://github.com/torvalds/linux/commit/07678eca2cf9c9a18584e546c2b2a0d0c9a3150c

Comment 1 Adam Mariš 2017-06-16 11:28:55 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1462173]

Comment 2 Justin M. Forbes 2017-06-16 12:01:11 UTC

In Fedora, this is fixed with the 4.11.5 stable update currently available across all releases.

Comment 5 Vladis Dronov 2017-06-19 15:40:47 UTC

Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 as the code where the flaw was found is not present in this product.

This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 6, 7 and MRG-2. This has been rated as having Low security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.