Bug 2036100 (CVE-2021-39685)

Summary: CVE-2021-39685 kernel: USB gadget buffer overflow
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: acaringi, adscvr, airlied, alciregi, allarkin, bdettelb, bhu, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jfaracco, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, lzampier, masami256, mchehab, nmurray, ptalbert, qzhao, rvrbovsk, scweaver, steved, vkumar, walters, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
An out of bounds memory access flaw in the Linux kernel's USB Peripheral Controller functionality was found in the way users call control request handlers in a specific way for the USB gadget. A local user could use this flaw to crash the system or escalate their privileges on the system.
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Clone Of: Environment:
Last Closed: 2021-12-30 08:48:44 UTC Type: ---
Regression: --- Mount Type: ---
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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: 2036101    
Bug Blocks: 2036102    

Description Guilherme de Almeida Suckevicz 2021-12-29 17:55:15 UTC 
An attacker can access kernel memory bypassing valid buffer boundaries by exploiting implementation of control request handlers in the following usb gadgets - rndis, hid, uac1, uac1_legacy and uac2. Processing of malicious control transfer requests with unexpectedly large wLength lacks assurance that this value does not exceed the buffer size. Due to this fact one is capable of reading and/or writing (depending on particular case) up to 65k of kernel memory.

Reference:
https://www.openwall.com/lists/oss-security/2021/12/15/4
Comment 1 Guilherme de Almeida Suckevicz 2021-12-29 17:56:58 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2036101]
Comment 5 Justin M. Forbes 2022-01-05 13:40:29 UTC 
This was fixed for Fedora with the 5.15.8 stable kernel update.