CVE-2021-47004
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- EPSS
- 0.24% probability · 15th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/105155a8146ddb54c119d8318964eef3859d109dPatch
- https://git.kernel.org/stable/c/1e116f87825f01a6380286472196882746b16f63Patch
- https://git.kernel.org/stable/c/211372b2571520e394b56b431a0705586013b3ffPatch
- https://git.kernel.org/stable/c/61461fc921b756ae16e64243f72af2bfc2e620dbPatch
- https://git.kernel.org/stable/c/105155a8146ddb54c119d8318964eef3859d109dPatch
- https://git.kernel.org/stable/c/1e116f87825f01a6380286472196882746b16f63Patch
- https://git.kernel.org/stable/c/211372b2571520e394b56b431a0705586013b3ffPatch
- https://git.kernel.org/stable/c/61461fc921b756ae16e64243f72af2bfc2e620dbPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.