Bug 2013242 (CVE-2021-20321) - CVE-2021-20321 kernel: In Overlayfs missing a check for a negative dentry before calling vfs_rename()
Summary: CVE-2021-20321 kernel: In Overlayfs missing a check for a negative dentry bef...
Keywords:
Status: NEW
Alias: CVE-2021-20321
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2010887 2011181 2013305 2016378 2026897 2013304 2013317 2013318 2013713
Blocks: 2013544 2011920
TreeView+ depends on / blocked
 
Reported: 2021-10-12 12:36 UTC by Alex
Modified: 2021-11-26 11:55 UTC (History)
44 users (show)

Fixed In Version: kernel 5.15-rc5
Doc Type: If docs needed, set a value
Doc Text:
A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.
Clone Of:
Environment:
Last Closed:


Attachments (Terms of Use)

Description Alex 2021-10-12 12:36:50 UTC
An attacker with a low-privileged user on a Linux machine with an overlay mount can escalate his privileges up to root when performing rename in specific way with this overlayfs.

Reference:
a295aef603e1 ("ovl: fix missing negative dentry check in ovl_rename()")


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