Bug 2219803 (CVE-2023-32247, ZDI-23-695, ZDI-CAN-20478)

Summary: CVE-2023-32247 kernel: ksmbd: session setup memory exhaustion denial-of-service vulnerability
Product: [Other] Security Response Reporter: Mauro Matteo Cascella <mcascell>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: 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 handling of SMB2_SESSION_SETUP commands. The issue results from the lack of control of resource consumption. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2023-07-05 12:29:11 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 12:25:51 UTC 
A memory exhaustion issue was found in ksmbd, a high-performance in-kernel SMB server. Quoting ZDI security advisory [1]:

"This vulnerability allows remote attackers to create a denial-of-service condition 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 handling of SMB2_SESSION_SETUP commands. The issue results from the lack of control of resource consumption. An attacker can leverage this vulnerability to create a denial-of-service condition on the system."

[1] https://www.zerodayinitiative.com/advisories/ZDI-CAN-20478/
Comment 1 Mauro Matteo Cascella 2023-07-05 12:26:11 UTC 
Upstream fix:
https://github.com/torvalds/linux/commit/ea174a91893956450510945a0c5d1a10b5323656