CVE-2021-47004

f2fs: fix to avoid touching checkpointed data in get_victim()

Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid touching checkpointed data in get_victim() In CP disabling mode, there are two issues when using LFS or SSR | AT_SSR mode to select victim: 1. LFS is set to find source section during GC, the victim should have no checkpointed data, since after GC, section could not be set free for reuse. Previously, we only check valid chpt blocks in current segment rather than section, fix it. 2. SSR | AT_SSR are set to find target segment for writes which can be fully filled by checkpointed and newly written blocks, we should never select such segment, otherwise it can cause panic or data corruption during allocation, potential case is described as below: a) target segment has 'n' (n < 512) ckpt valid blocks b) GC migrates 'n' valid blocks to other segment (segment is still in dirty list) c) GC migrates '512 - n' blocks to target segment (segment has 'n' cp_vblocks and '512 - n' vblocks) d) If GC selects target segment via {AT,}SSR allocator, however there is no free space in targe segment.

7.1
CVSS
Severity: High
CVSS 3.1 •
EPSS 0.04%
Affected: Linux Linux
Affected: Linux Linux
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-47004?
CVE-2021-47004 has been scored as a high severity vulnerability.
How to fix CVE-2021-47004?
To fix CVE-2021-47004, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47004 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-47004 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47004?
CVE-2021-47004 affects Linux Linux, Linux Linux.
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