Bug 1163744 (CVE-2014-7843)

Summary: CVE-2014-7843 kernel: aarch64: copying from /dev/zero causes local DoS
Product: [Other] Security Response Reporter: Petr Matousek <pmatouse>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: agordeev, aquini, bhu, davej, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, jonathan, jross, jrusnack, jwboyer, kernel-maint, kernel-mgr, kmcmartin, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-11-13 12:02:02 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1161020, 1163745    
Bug Blocks: 1163133    

Description Petr Matousek 2014-11-13 12:00:25 UTC
It was found that a read of n*PAGE_SIZE+1 from /dev/zero
will cause the kernel to panic due to an unhandled exception since it's
not handling the single byte case with a fixup (anything larger than a
single byte will properly fault.)

A local, unprivileged user could use this flaw to crash the system.

Upstream patch proposal:



This issue was discovered by Miloš Prchlík of Red Hat.

Comment 1 Petr Matousek 2014-11-13 12:02:02 UTC
Statement CVE-2014-7825:

Not vulnerable.

This issue does not affect the Linux kernel packages as shipped with Red Hat
Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.

Comment 2 Petr Matousek 2014-11-13 12:02:36 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1163745]

Comment 3 Fedora Update System 2014-11-18 12:17:35 UTC
kernel-3.17.3-300.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 4 Fedora Update System 2014-11-20 23:04:02 UTC
kernel-3.17.3-200.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.