Bug 1649017 (CVE-2018-16862) - CVE-2018-16862 kernel: cleancache: Infoleak of deleted files after reuse of old inodes
Summary: CVE-2018-16862 kernel: cleancache: Infoleak of deleted files after reuse of o...
Keywords:
Status: CLOSED WONTFIX
Alias: CVE-2018-16862
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: 1653122
Blocks: 1649018
TreeView+ depends on / blocked
 
Reported: 2018-11-12 17:47 UTC by Pedro Sampaio
Modified: 2021-02-16 22:47 UTC (History)
44 users (show)

Fixed In Version:
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Doc Text:
A security flaw was found in the Linux kernel in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and the old file data instead of the new one.
Clone Of:
Environment:
Last Closed: 2019-06-10 10:42:24 UTC

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Description Pedro Sampaio 2018-11-12 17:47:55 UTC 
A security flaw was found in the Linux kernel in a way that the cleancache subsystem clears an inode after the final file truncation (removal). The new file created with the same inode may contain leftover pages from cleancache and so the old file data instead of the new one.

References:

https://seclists.org/oss-sec/2018/q4/169

A suggested patch:

https://lore.kernel.org/patchwork/patch/1011367/
Comment 3 Vladis Dronov 2018-11-23 15:10:08 UTC 
Acknowledgments:

Name: Vasily Averin (Virtuozzo Kernel Team), Pavel Tikhomirov (Virtuozzo Kernel Team)
Comment 4 Vladis Dronov 2018-11-23 15:32:16 UTC 
Note:

While RHEL-ALT and RHEL-8 are vulnerable to this flaw, only Xen's [tmem] driver is a possible backend for the CleanCache subsystem. So, a vulnerable configuration is RHEL as a Xen's guest. According to https://access.redhat.com/certified-hypervisors this is not a supported configuration, and so the flaw is not currently planned to be addressed in future updates.
Comment 5 Sam Fowler 2018-11-26 00:05:03 UTC 
External Reference:

https://seclists.org/oss-sec/2018/q4/169
Comment 6 Sam Fowler 2018-11-26 00:06:11 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1653122]
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