Bug 1784942 (CVE-2019-19241)

Summary:	CVE-2019-19241 kernel: privilege escalation via io_uring offload of sendmsg() onto kernel thread with kernel creds
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bdettelb, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jschorr, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, qzhao, rt-maint, rvrbovsk, steved, williams
Target Milestone:	---	Keywords:	Reopened, Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-09-07 13:17:46 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:	1784945, 1876428, 1876429
Bug Blocks:	1784943

Description Guilherme de Almeida Suckevicz 2019-12-18 18:58:20 UTC

In the Linux kernel before 5.4.2, the io_uring feature leads to requests that inadvertently have UID 0 and full capabilities. This is related to fs/io-wq.c, fs/io_uring.c, and net/socket.c. For example, an attacker can bypass intended restrictions on adding an IPv4 address to the loopback interface. This occurs because IORING_OP_SENDMSG operations, although requested in the context of an unprivileged user, are sometimes performed by a kernel worker thread without considering that context.

Reference:
https://bugs.chromium.org/p/project-zero/issues/detail?id=1975

Upstream commits:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=181e448d8709e517c9c7b523fcd209f24eb38ca7
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d69e07793f891524c6bbf1e75b9ae69db4450953

Comment 1 Guilherme de Almeida Suckevicz 2019-12-18 18:59:31 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1784945]

Comment 2 Justin M. Forbes 2019-12-19 15:24:10 UTC

This is fixed for Fedora with the 5.3.15 stable kernel updates.

Comment 3 Wade Mealing 2020-02-06 02:44:28 UTC

Statement:

At this time, no Red Hat Enterprise Linux products ship with support for this feature.  There is an outstanding feature request for io_uring to be included with Red Hat Enterprise Linux 8.

Comment 4 Wade Mealing 2020-02-06 02:46:28 UTC

Feature request here: 

https://bugzilla.redhat.com/show_bug.cgi?id=1706143

Engineering has been made aware of the patches required to fix the CVE in that feature request and product security's request to have these patches included pre-release.

Comment 5 Product Security DevOps Team 2020-06-04 17:20:23 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-2019-19241

Comment 7 Product Security DevOps Team 2020-09-07 13:17:46 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-2019-19241