Bug 2026487 (CVE-2021-4148) - CVE-2021-4148 kernel: Improper implementation of block_invalidatepage() allows users to crash the kernel
Summary: CVE-2021-4148 kernel: Improper implementation of block_invalidatepage() allow...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2021-4148
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: 2034507 2034508 2034509 2034510
Blocks: 2026492 2034660
TreeView+ depends on / blocked
 
Reported: 2021-11-24 20:06 UTC by Pedro Sampaio
Modified: 2022-05-19 11:39 UTC (History)
44 users (show)

Fixed In Version: kernel 5.14.16
Clone Of:
Environment:
Last Closed: 2022-05-18 06:02:46 UTC
Embargoed:

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Description Pedro Sampaio 2021-11-24 20:06:50 UTC 
In the Linux kernel before 5.15, improper implementation of block_invalidatepage() allows users to crash the kernel. As long as the page passed to block_invalidatepage() is a huge page and the length is the size of the huge page instead of a single page due to read-only FS THP support, the operation would throw BUG if the size is greater than a single page. Furthermore, all the implementations that are *NOT* THP aware and hardcoded PAGE_SIZE can trigger BUG(), like block_invalidatepage().

References:

https://lkml.org/lkml/2021/9/17/1037
https://lkml.org/lkml/2021/9/12/323
Comment 4 Rohit Keshri 2021-12-21 07:45:11 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2034507]
Comment 11 Justin M. Forbes 2022-03-16 16:28:28 UTC 
This issue was fixed for Fedora with the 5.14.16 stable kernel updates.
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