Bug 1549586 (CVE-2017-18200)

Summary: CVE-2017-18200 kernel: mishandling reference counts associated with f2fs_wait_discard_bios calls allowing local attacker to cause denial of service
Product: [Other] Security Response Reporter: Adam Mariš <amaris>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: airlied, ajax, aquini, bhu, blc, bskeggs, dhoward, esammons, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, iboverma, ichavero, itamar, jarodwilson, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jross, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, lwang, matt, mchehab, mcressma, mguzik, mjg59, mlangsdo, nmurray, plougher, rt-maint, rvrbovsk, skozina, steved, vdronov, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 4.14 Doc Type: If docs needed, set a value
Doc Text:
The f2fs implementation in the Linux kernel, before 4.14, mishandles reference counts associated with f2fs_wait_discard_bios calls. This allows local users to cause a denial of service (BUG), as demonstrated by fstrim.
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-03-01 14:22:45 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: 1550580    
Bug Blocks: 1549588    

Description Adam Mariš 2018-02-27 13:19:12 UTC
The f2fs implementation in the Linux kernel before 4.14 mishandles reference counts associated with f2fs_wait_discard_bios calls, which allows local users to cause a denial of service (BUG), as demonstrated by fstrim.

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=638164a2718f337ea224b747cf5977ef143166a4

Comment 2 Vladis Dronov 2018-03-01 14:16:45 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1550580]

Comment 4 Vladis Dronov 2018-03-01 14:22:45 UTC
Statement:

This issue does not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5, 6, 7, its real-time kernel, Red Hat Enterprise MRG 2, Red Hat Enterprise Linux 7 for ARM 64 and Red Hat Enterprise Linux 7 for Power 9 LE, as the code with the flaw is not built and shipped in the products listed.

Comment 5 Justin M. Forbes 2018-03-01 16:06:30 UTC
This was fixed in 4.14 rebases for all Fedora releases.