Double Free Affecting kernel-core package, versions <0:5.14.0-284.75.1.el9_2
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Test your applications- Snyk ID SNYK-RHEL9-KERNELCORE-7563765
- published 25 Jul 2024
- disclosed 3 Apr 2024
Introduced: 3 Apr 2024
CVE-2024-26704 Open this link in a new tabHow to fix?
Upgrade RHEL:9 kernel-core to version 0:5.14.0-284.75.1.el9_2 or higher.
This issue was patched in RHSA-2024:4823.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL.
See How to fix? for RHEL:9 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix double-free of blocks due to wrong extents moved_len
In ext4_move_extents(), moved_len is only updated when all moves are successfully executed, and only discards orig_inode and donor_inode preallocations when moved_len is not zero. When the loop fails to exit after successfully moving some extents, moved_len is not updated and remains at 0, so it does not discard the preallocations.
If the moved extents overlap with the preallocated extents, the overlapped extents are freed twice in ext4_mb_release_inode_pa() and ext4_process_freed_data() (as described in commit 94d7c16cbbbd ("ext4: Fix double-free of blocks with EXT4_IOC_MOVE_EXT")), and bb_free is incremented twice. Hence when trim is executed, a zero-division bug is triggered in mb_update_avg_fragment_size() because bb_free is not zero and bb_fragments is zero.
Therefore, update move_len after each extent move to avoid the issue.
References
- https://access.redhat.com/security/cve/CVE-2024-26704
- https://git.kernel.org/stable/c/185eab30486ba3e7bf8b9c2e049c79a06ffd2bc1
- https://git.kernel.org/stable/c/2883940b19c38d5884c8626483811acf4d7e148f
- https://git.kernel.org/stable/c/55583e899a5357308274601364741a83e78d6ac4
- https://git.kernel.org/stable/c/559ddacb90da1d8786dd8ec4fd76bbfa404eaef6
- https://git.kernel.org/stable/c/afba9d11320dad5ce222ac8964caf64b7b4bedb1
- https://git.kernel.org/stable/c/afbcad9ae7d6d11608399188f03a837451b6b3a1
- https://git.kernel.org/stable/c/b4fbb89d722cbb16beaaea234b7230faaaf68c71
- https://git.kernel.org/stable/c/d033a555d9a1cf53dbf3301af7199cc4a4c8f537
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html