Bug 1771496 (CVE-2019-18805)

Summary:	CVE-2019-18805 kernel: integer overflow in tcp_ack_update_rtt in net/ipv4/tcp_input.c
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, 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, plougher, qzhao, rkeshri, rt-maint, rvrbovsk, steved, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A flaw was reported in the Linux kernel's TCP subsystem while calculating a packet round trip time, when a sysctl parameter (/proc/sys/net/ipv4/tcp_min_rtt_wlen) is set incorrectly. This causes an integer overflow which can lead to a denial Of service (DOS) attack.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-03-09 16:31:54 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:	1771498, 1773862, 1773863, 1773864
Bug Blocks:	1771499

Description Guilherme de Almeida Suckevicz 2019-11-12 13:37:41 UTC

A flaw was reported in kernel TCP subsystem while calculating a packet round trip time, when a sysctl parameter (/proc/sys/net/ipv4/tcp_min_rtt_wlen) when is set wrongly. This causes an integer over flaw which can lead to a Denial Of Service (DOS) attack.  


Additional Information:
-----------------------
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19fad20d15a6494f47f85d869f00b11343ee5c78

Comment 1 Guilherme de Almeida Suckevicz 2019-11-12 13:38:05 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1771498]

Comment 2 Justin M. Forbes 2019-11-12 18:08:36 UTC

This was fixed for Fedora with the 5.0.11 stable kernel updates.

Comment 7 Eric Christensen 2019-11-20 16:44:11 UTC

Mitigation:

This flaw can be mitigated by setting the sysctl parameter (/proc/sys/net/ipv4/tcp_min_rtt_wlen) with 300 which means the packet time will not exceed more then 5 minutes and which should not cause an integer overflow.

Comment 8 errata-xmlrpc 2020-03-09 14:31:58 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:0740 https://access.redhat.com/errata/RHSA-2020:0740

Comment 9 Product Security DevOps Team 2020-03-09 16:31:54 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-2019-18805

Comment 10 errata-xmlrpc 2020-04-28 15:25:09 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:1567 https://access.redhat.com/errata/RHSA-2020:1567

Comment 11 errata-xmlrpc 2020-04-28 15:51:38 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:1769 https://access.redhat.com/errata/RHSA-2020:1769