Bug 1979666 (CVE-2021-36086)

Summary: CVE-2021-36086 libsepol: use-after-free in cil_reset_classpermission()
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: caswilli, dwalsh, fjansen, jnakfour, kaycoth, lvrabec, mmalik, plautrba, psampaio, psegedy, vmojzis, vmugicag
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Last Closed: 2021-11-10 00:23:51 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 1979667, 1983523, 1983524, 1983525, 1983527, 1984931    
Bug Blocks: 1979670    

Description Guilherme de Almeida Suckevicz 2021-07-06 16:54:38 UTC 
The CIL compiler in SELinux 3.2 has a use-after-free in cil_reset_classpermission (called from cil_reset_classperms_set and cil_reset_classperms_list).

References:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=32177
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/selinux/OSV-2021-536.yaml

Upstream patch:
https://github.com/SELinuxProject/selinux/commit/c49a8ea09501ad66e799ea41b8154b6770fec2c8
Comment 1 Guilherme de Almeida Suckevicz 2021-07-06 16:54:57 UTC 
Created libsepol tracking bugs for this issue:

Affects: fedora-all [bug 1979667]
Comment 4 Garrett Tucker 2021-07-26 13:53:50 UTC 
selinux/libsepol is mostly local access and to perform this attack would require local access as compared to network access. An attacker would also require some form of privileges to write the policy file and compile the CIL. The availability impact is also low as this flaw would not cause a system wide or complete lack of availability. Instead the attack would only impact availability of selinux temporarily.
Comment 5 errata-xmlrpc 2021-11-09 19:03:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:4513 https://access.redhat.com/errata/RHSA-2021:4513
Comment 6 Product Security DevOps Team 2021-11-10 00:23:48 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-36086
Comment 7 Guilherme de Almeida Suckevicz 2023-04-18 15:02:07 UTC 
*** Bug 2184112 has been marked as a duplicate of this bug. ***