Bug 1225052 (CVE-2021-47316)

Summary: VUL-0: CVE-2021-47316: kernel: nfsd: fix NULL dereference in nfs3svc_encode_getaclres
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Security Team bot <security-team>
Status: RESOLVED FIXED QA Contact: Security Team bot <security-team>
Severity: Normal    
Priority: P3 - Medium CC: camila.matos, jlee
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/406952/
Whiteboard: CVSSv3.1:SUSE:CVE-2021-47316:5.5:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-05-22 16:30:23 UTC 
In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix NULL dereference in nfs3svc_encode_getaclres

In error cases the dentry may be NULL.

Before 20798dfe249a, the encoder also checked dentry and
d_really_is_positive(dentry), but that looks like overkill to me--zero
status should be enough to guarantee a positive dentry.

This isn't the first time we've seen an error-case NULL dereference
hidden in the initialization of a local variable in an xdr encoder.  But
I went back through the other recent rewrites and didn't spot any
similar bugs.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47316
https://www.cve.org/CVERecord?id=CVE-2021-47316
https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870
https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2021/CVE-2021-47316.mbox
Comment 2 Andrea Mattiazzo 2024-05-29 12:05:41 UTC 
All done, closing.