Bug 1334316 (CVE-2016-4568)

Summary: CVE-2016-4568 kernel: videobuf2-v412: Planes array amount not verified in buffer dequeueing
Product: [Other] Security Response Reporter: Andrej Nemec <anemec>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: aquini, arm-mgr, bhu, dhoward, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, madhu.chinakonda, matt, mchehab, mcressma, nmurray, plougher, rt-maint, rvrbovsk, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2019-06-08 02:51:23 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: 1334317    
Bug Blocks:    

Description Andrej Nemec 2016-05-09 11:38:21 UTC
 When a buffer is being dequeued using VIDIOC_DQBUF IOCTL, the exact buffer which will be dequeued is not known until the buffer has been removed from the queue. The number of planes is specific to a buffer, not to the queue.
    
This does lead to the situation where multi-plane buffers may be requested and queued with n planes, but VIDIOC_DQBUF IOCTL may be passed an argument struct with fewer planes.
    
__fill_v4l2_buffer() however uses the number of planes from the dequeued videobuf2 buffer, overwriting kernel memory (the m.planes array allocated in video_usercopy() in v4l2-ioctl.c)  if the user provided fewer planes than the dequeued buffer had.

References:

http://seclists.org/oss-sec/2016/q2/272

Upstream fix:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2c1f6951a8a82e6de0d82b1158b5e493fc6c54ab

Introduced by:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b0e0e1f83de31aa0428c38b692c590cc0ecd3f03

Comment 1 Andrej Nemec 2016-05-09 11:39:26 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1334317]