Linux Kernel up to 5.17.13/5.18.2 z_erofs_shifted_transform use after free

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 5.17.13/5.18.2. This vulnerability affects the function z_erofs_shifted_transform. Executing a manipulation can lead to use after free. This vulnerability is tracked as CVE-2022-49464. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.17.13/5.18.2. This vulnerability affects the function z_erofs_shifted_transform. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: erofs: fix buffer copy overflow of ztailpacking feature I got some KASAN report as below: [ 46.959738] ================================================================== [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188 ... [ 46.960430] Call Trace: [ 46.960430] [ 46.960430] dump_stack_lvl+0x41/0x5e [ 46.960430] print_report.cold+0xb2/0x6b7 [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] kasan_report+0x8a/0x140 [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] kasan_check_range+0x14d/0x1d0 [ 46.960430] memcpy+0x20/0x60 [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370 [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080 The root cause is that the tail pcluster won't be a complete filesystem block anymore. So if ztailpacking is used, the second part of an uncompressed tail pcluster may not be ``rq->pageofs_out``.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2022-49464 since 02/26/2025. The exploitation appears to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/25/2025).

Upgrading to version 5.17.14 or 5.18.3 eliminates this vulnerability. Applying the patch 4d53a625f29074e7b8236c2c0e0922edb7608df9/6b59e1907f58cf877c563dcf013159eb9f994b64/dcbe6803fffd387f72b48c2373b5f5ed12a5804b is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.17.0
• 5.17.1
• 5.17.2
• 5.17.3
• 5.17.4
• 5.17.5
• 5.17.6
• 5.17.7
• 5.17.8
• 5.17.9
• 5.17.10
• 5.17.11
• 5.17.12
• 5.17.13
• 5.18.0
• 5.18.1
• 5.18.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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CPE 2.2info

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