[SRU][J][PATCH 0/1] CVE-2024-41014

[Massimiliano Pellizzer]

https://ubuntu.com/security/CVE-2024-41014

[ Impact ]

xfs: add bounds checking to xlog_recover_process_data

There is a lack of verification of the space occupied by fixed members
of xlog_op_header in the xlog_recover_process_data.

We can create a crafted image to trigger an out of bounds read by
following these steps:
    1) Mount an image of xfs, and do some file operations to leave records
    2) Before umounting, copy the image for subsequent steps to simulate
       abnormal exit. Because umount will ensure that tail_blk and
       head_blk are the same, which will result in the inability to enter
       xlog_recover_process_data
    3) Write a tool to parse and modify the copied image in step 2
    4) Make the end of the xlog_op_header entries only 1 byte away from
       xlog_rec_header->h_size
    5) xlog_rec_header->h_num_logops++
    6) Modify xlog_rec_header->h_crc

Add a check to make sure there is sufficient space to access fixed members
of xlog_op_header.


[ Fix ]

Backport fix commit from mainline:
- fb63435b7c7d xfs: add bounds checking to xlog_recover_process_data

[ Test Plan ]

Compile tested only.

[ Where Problems Could Occur ]

The fix adds a simple check in the recovery process of XFS,
which gets called when mounting the filesystem.
A proble with the patch will cause errors during mounting
of XFS partitions.