Bug 2221472 (CVE-2023-3108)

Summary: CVE-2023-3108 kernel: A race condition in crypto module in the function skcipher_recvmsg
Product: [Other] Security Response Reporter: Alex <allarkin>
Component: vulnerabilityAssignee: Nobody <nobody>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, allarkin, bhu, chwhite, dbohanno, ddepaula, debarbos, dfreiber, dvlasenk, ezulian, herbert.xu, hkrzesin, jarod, jburrell, jdenham, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, kernel-mgr, ldoskova, lgoncalv, lleshchi, lzampier, nmurray, ptalbert, qzhao, rogbas, rrobaina, rvrbovsk, rysulliv, scweaver, security-response-team, swood, tglozar, tyberry, vkumar, walters, wcosta, williams, wmealing, ycote, ymankad
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 4.0-rc1 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the subsequent get_user_pages_fast in the Linux kernel’s interface for symmetric key cipher algorithms in the skcipher_recvmsg of crypto/algif_skcipher.c function. This flaw allows a local user to crash the system.
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2221474, 2221475, 2221476, 2221477, 2221807    
Bug Blocks: 2211869    

Description Alex 2023-07-09 10:29:13 UTC 
A flaw in the Linux Kernel interface for symmetric key cipher algorithms found (in the function skcipher_recvmsg of crypto/algif_skcipher.c). When the function skcipher_recvmsg receives data from the socket to obtain the encryption and decryption results, it can go to skcipher_wait_for_data to wait for the data in the socket to arrive, but the value passed to af_alg_make_sg after the data arrives is still 0, which will cause a crash in the subsequent get_user_pages_fast. After analyses of the reproducer, there is a conclusion that this issue is only locally exploitable.

Reference:
https://github.com/torvalds/linux/commit/9399f0c51489ae8c16d6559b82a452fdc1895e91
Comment 6 Alex 2023-07-10 20:42:05 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2221807]
Comment 7 Justin M. Forbes 2023-07-18 18:31:33 UTC 
The fix for this was brought in during 4.0, and has not impacted any Fedora kernels in the past 8 years.