Bug 2056061 (CVE-2021-44730)

Summary: CVE-2021-44730 snapd: Hardlink attack in snap-confine's sc_open_snapd_tool()
Product: [Other] Security Response Reporter: Mauro Matteo Cascella <mcascell>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED UPSTREAM QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: go-sig, maciek.borzecki, me, ngompa13
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: snapd 2.54.3 Doc Type: If docs needed, set a value
Doc Text:
A hardlink attack in the snap-confine component (sc_open_snapd_tool) of snapd was found by Qualys. This flaw is exploitable in a non-default configuration only (when the kernel's fs.protected_hardlinks is 0) and could lead to local privilege escalation from any user to root.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2022-03-02 20:50:58 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: 2056062, 2056063    
Bug Blocks:    

Description Mauro Matteo Cascella 2022-02-18 16:42:22 UTC 
A hardlink attack in the snap-confine component (sc_open_snapd_tool) of snapd was found by Qualys. This flaw is exploitable in a non-default configuration only (when the kernel's fs.protected_hardlinks is 0) and could lead to local privilege escalation from any user to root.

Qualys security advisory:
https://www.qualys.com/2022/02/17/cve-2021-44731/oh-snap-more-lemmings.txt
Comment 1 Mauro Matteo Cascella 2022-02-18 16:42:42 UTC 
Created snapd tracking bugs for this issue:

Affects: epel-all [bug 2056062]
Affects: fedora-all [bug 2056063]
Comment 2 Product Security DevOps Team 2022-03-02 20:50:56 UTC 
This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.