Bug 1989216 (CVE-2021-35477)

Summary:	CVE-2021-35477 kernel: BPF program can obtain sensitive information from kernel memory via a speculative store bypass side-channel attack because the technique used by the BPF verifier to manage speculation is unreliable
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, bdettelb, bhu, blc, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jeremy, jforbes, jlelli, jonathan, josef, jpazdziora, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rvrbovsk, steved, tomckay, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.14-rc4	Doc Type:	If docs needed, set a value
Doc Text:	A flaw in the Linux kernel allows a privileged BPF program to obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel in the eBPF subsystem	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-11-08 01:52:50 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:	1989217, 1989782, 1989783, 1989801
Bug Blocks:	1989218

Description Guilherme de Almeida Suckevicz 2021-08-02 16:44:55 UTC

A flaw in the Linux kernel allows a privileged BPF program to obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

References:
https://www.openwall.com/lists/oss-security/2021/08/01/3
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=f5e81d1117501546b7be050c5fbafa6efd2c722c
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=2039f26f3aca5b0e419b98f65dd36481337b86ee

Comment 1 Guilherme de Almeida Suckevicz 2021-08-02 16:45:35 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1989217]