Bug 1539508 (CVE-2017-18075)

Summary:	CVE-2017-18075 kernel: Mishandled freeing of instances in pcrypt.c can allow a local user to cause a denial of service
Product:	[Other] Security Response	Reporter:	Sam Fowler <sfowler>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	airlied, ajax, aquini, bhu, blc, bskeggs, dhoward, 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, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, plougher, rt-maint, rvrbovsk, skozina, slawomir, steved, vdronov, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 4.14.13	Doc Type:	Bug Fix
Doc Text:	crypto/pcrypt.c in the Linux kernel, before 4.14.13, mishandles freeing instances, allowing a local user able to access the AF_ALG-based AEAD interface (CONFIG_CRYPTO_USER_API_AEAD) and pcrypt (CONFIG_CRYPTO_PCRYPT) to cause a denial of service (kfree of an incorrect pointer) or possibly have unspecified other impact by executing a crafted sequence of system calls. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 03:38:26 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:	1546457, 1546458
Bug Blocks:	1539509

Description Sam Fowler 2018-01-29 04:52:19 UTC

crypto/pcrypt.c in the Linux kernel before 4.14.13 mishandles freeing instances, allowing a local user able to access the AF_ALG-based AEAD interface (CONFIG_CRYPTO_USER_API_AEAD) and pcrypt (CONFIG_CRYPTO_PCRYPT) to cause a denial of service (kfree of an incorrect pointer) or possibly have unspecified other impact by executing a crafted sequence of system calls. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.

References:

https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.13

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d76c68109f37cb85b243a1cf0f40313afd2bae68

Comment 2 Vladis Dronov 2018-02-17 18:50:33 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1546457]

Comment 6 Justin M. Forbes 2018-02-19 14:46:03 UTC

This was fixed for Fedora with the 4.14.13 stable updates.

Comment 7 Eric Christensen 2018-02-19 15:29:32 UTC

Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, and 7, its real-time kernel and Red Hat Enterprise MRG 2, as the code with the flaw is not enabled and is not built in the products listed.

This issue affects the Linux kernel packages as shipped with  Red Hat Enterprise Linux 7 for ARM 64 and Red Hat Enterprise Linux 7 for Power 9 LE. Future Linux kernel updates for the respective releases may address this issue.

Comment 8 errata-xmlrpc 2018-10-30 08:57:06 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:2948 https://access.redhat.com/errata/RHSA-2018:2948