Bug 1616245 (CVE-2018-15572)

Summary: CVE-2018-15572 Kernel: hw: cpu: userspace-userspace spectreRSB attack
Product: [Other] Security Response Reporter: Prasad Pandit <ppandit>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: airlied, aquini, bhu, blc, bskeggs, dhoward, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, iboverma, ichavero, itamar, jarodwilson, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jstancek, jwboyer, kernel-maint, kernel-mgr, knweiss, labbott, lgoncalv, linville, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, plougher, psampaio, rt-maint, rvrbovsk, skozina, steved, williams, yozone
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 4.18.1 Doc Type: Bug Fix
Doc Text:
An issue was found in the way modern x86 microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization) and prediction of return addresses via Return Stack Buffer (RSB). RSB is a small on chip structure that holds list of return addresses, used to predict function return addresses. An unprivileged attacker could use this flaw to cross the syscall or process boundary and read privileged memory by conducting targeted cache side-channel attacks.
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-04-22 04:32:03 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: 1616246, 1616248    
Bug Blocks: 1609190, 1619447    

Description Prasad Pandit 2018-08-15 11:49:14 UTC
An issue was found in the way modern x86 microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimisation) and prediction of return addresses via Return Stack Buffer(RSB). RSB is a small on chip structure that holds list of return addresses, used to predict function return addresses.

An unprivileged attacker could use this flaw to cross the syscall or process boundary and read privileged memory by conducting targeted cache side-channel attacks.

Upstream patch:
---------------
  -> https://git.kernel.org/linus/fdf82a7856b32d905c39afc85e34364491e46346

References:
-----------
  -> https://arxiv.org/pdf/1807.07940.pdf
  -> https://christian-rossow.de/publications/ret2spec-ccs2018.pdf

Comment 1 Prasad Pandit 2018-08-15 11:49:16 UTC
Acknowledgments:

Name: Giorgi Maisuradze (Saarland University), Christian Rossow (Saarland University), Nael Abu-Ghazaleh (University of California), Esmaiel Mohammadian Koruyeh (University of California), Khaled Khasawneh (University of California), Chengyu Song (University of California)

Comment 2 Prasad Pandit 2018-08-15 11:50:17 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1616246]

Comment 5 Justin M. Forbes 2018-08-15 20:09:26 UTC
This is fixed for Fedora with the 4.17.14-202 stable update kernels.

Comment 6 Wade Mealing 2018-08-21 07:53:47 UTC
*** Bug 1619446 has been marked as a duplicate of this bug. ***

Comment 7 Karsten Weiss 2018-08-22 11:08:15 UTC
@Prasad: Could you please explain why this issue does not affect the RHEL 5, 6, 7 kernels?

Comment 8 Prasad Pandit 2018-08-28 13:17:34 UTC
Hello Karsten,

(In reply to Karsten Weiss from comment #7)
> @Prasad: Could you please explain why this issue does not affect the RHEL 5,
> 6, 7 kernels?

SpectreRSB attack requires that kernel does not fill Return Stack Buffer (RSB) upon context switch and/or VM entry/exit. And SMEP is disabled.

RHEL-5 fills RSB when SMEP is enabled. Whereas RHEL 6, 7 kernels do it unconditionally whether SMEP is on or off. Upstream patch above does the same.

Comment 9 Eric Christensen 2018-12-14 02:30:12 UTC
Statement:

This issue affects the version of the kernel package as shipped with Red Hat Enterprise Linux 5.

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

Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.

Comment 11 Product Security DevOps Team 2020-04-22 04:32:03 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2018-15572