Bug 1905155 (CVE-2020-27825)

Summary: CVE-2020-27825 kernel: use-after-free in the ftrace ring buffer resizing logic due to a race condition
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Nobody <nobody>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, adscvr, airlied, bhu, blc, bmasney, dvlasenk, hdegoede, hkrzesin, itamar, jarodwilson, jeremy, jforbes, jlelli, jmarchan, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rkeshri, rt-maint, rvrbovsk, steved, walters, williams, zsun
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 5.10-rc1 Doc Type: If docs needed, set a value
Doc Text:
A use-after-free flaw was found in kernel/trace/ring_buffer.c in Linux kernel. There was a race problem in trace_open and resize of cpu buffer running parallely on different cpus, may cause a denial of service problem (DOS). This flaw could even allow a local attacker with special user privilege to a kernel information leak threat.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1906409, 1906410, 1914746, 1914747, 1914748    
Bug Blocks: 1899203    

Description Guilherme de Almeida Suckevicz 2020-12-07 16:26:05 UTC 
A flaw was found in the Linux Kernel. A use-after-free vulnerability was discovered in the ftrace ring buffer resizing logic due to a race condition.

Reference and upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bbeb97464eefc65f506084fd9f18f21653e01137
Comment 3 Rohit Keshri 2020-12-09 13:11:36 UTC 
Mitigation:

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Comment 4 Guilherme de Almeida Suckevicz 2020-12-09 19:58:29 UTC 
Acknowledgments:

Name: Adam 'pi3' Zabrocki