Bug 2219806 (CVE-2023-32257, ZDI-23-705, ZDI-CAN-20596)

Summary:	CVE-2023-32257 kernel: ksmbd: session race condition remote code execution vulnerability
Product:	[Other] Security Response	Reporter:	Mauro Matteo Cascella <mcascell>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	acaringi, allarkin, bhu, chwhite, crwood, dbohanno, ddepaula, debarbos, dvlasenk, ezulian, hkrzesin, jarod, jdenham, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, kernel-mgr, ldoskova, lgoncalv, lleshchi, lzampier, nmurray, ptalbert, qzhao, rrobaina, rvrbovsk, rysulliv, scweaver, tglozar, tyberry, walters, wcosta, williams, wmealing, ycote, ymankad
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 6.4-rc1	Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's ksmbd, a high-performance in-kernel SMB server. The specific flaw exists within the processing of SMB2_SESSION_SETUP and SMB2_LOGOFF commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-07-05 12:36:46 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:
Bug Blocks:	2190273

Description Mauro Matteo Cascella 2023-07-05 12:36:25 UTC

An improper locking issue leading to a race condition vulnerability was found in ksmbd, a high-performance in-kernel SMB server. Quoting ZDI security advisory [1]:

"This vulnerability allows remote attackers to execute arbitrary code on affected installations of Linux Kernel. Authentication is not required to exploit this vulnerability, but only systems with ksmbd enabled are vulnerable.

The specific flaw exists within the processing of SMB2_SESSION_SETUP and SMB2_LOGOFF commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel."

[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20596/

Comment 1 Mauro Matteo Cascella 2023-07-05 12:36:46 UTC

Upstream fix:
https://github.com/torvalds/linux/commit/f5c779b7ddbda30866cf2a27c63e34158f858c73