CVE-2023-52497

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    CVE-2023-52497

    Published: 29 Feb 2024Last Modified: 12 Aug 2026

    Summary: erofs: fix lz4 inplace decompression

    Details: In the Linux kernel, the following vulnerability has been resolved: erofs: fix lz4 inplace decompression Currently EROFS can map another compressed buffer for inplace decompression, that was used to handle the cases that some pages of compressed data are actually not in-place I/O. However, like most simple LZ77 algorithms, LZ4 expects the compressed data is arranged at the end of the decompressed buffer and it explicitly uses memmove() to handle overlapping: __________________________________________________________ |_ direction of decompression --> ____ |_ compressed data _| Although EROFS arranges compressed data like this, it typically maps two individual virtual buffers so the relative order is uncertain. Previously, it was hardly observed since LZ4 only uses memmove() for short overlapped literals and x86/arm64 memmove implementations seem to completely cover it up and they don't have this issue. Juhyung reported that EROFS data corruption can be found on a new Intel x86 processor. After some analysis, it seems that recent x86 processors with the new FSRM feature expose this issue with "rep movsb". Let's strictly use the decompressed buffer for lz4 inplace decompression for now. Later, as an useful improvement, we could try to tie up these two buffers together in the correct order.

    References: https://git.kernel.org/stable/c/33bf23c9940dbd3a22aad7f0cda4c84ed5701847, https://git.kernel.org/stable/c/3c12466b6b7bf1e56f9b32c366a3d83d87afb4de, https://git.kernel.org/stable/c/77cbc04a1a8610e303a0e0d74f2676667876a184, https://git.kernel.org/stable/c/9ff2d260b25df6fe1341a79113d88fecf6bd553e, https://git.kernel.org/stable/c/a0180e940cf1aefa7d516e20b259ad34f7a8b379, https://git.kernel.org/stable/c/bffc4cc334c5bb31ded54bc3cfd651735a3cb79e, https://git.kernel.org/stable/c/f36d200a80a3ca025532ed60dd1ac21b620e14ae, https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html, https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52497.json, https://nvd.nist.gov/vuln/detail/CVE-2023-52497, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0ffd71bcc3a03ebb3551661a36052488369c4de9
    Fixed -9ff2d260b25df6fe1341a79113d88fecf6bd553e

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2023-52497 | CVE-DB