A vulnerability has been identified within the Linux kernel's xlog_recover_process_data() function. Specifically, the function lacks proper bounds checking on the space allocated for the fixed members of the xlog_op_header structure during log record processing. This omission can lead to an out-of-bounds memory access.
The potential impact of this flaw includes unpredictable system behavior and kernel-level crashes. Successful exploitation could disrupt system availability and potentially be leveraged for further malicious activities, depending on the context and any subsequent vulnerabilities exposed by the undefined behavior.
In the Linux kernel, the following vulnerability has been resolved:
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
Fix:
Add a check to make sure there is sufficient space to access fixed members
of xlog_op_header.
Comment 8Mauro Matteo Cascella
2024-07-29 17:02:45 UTC
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 2300530]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
Red Hat Enterprise Linux 8.6 Telecommunications Update Service
Via RHSA-2024:6297 https://access.redhat.com/errata/RHSA-2024:6297
In the Linux kernel, the following vulnerability has been resolved: 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 Fix: Add a check to make sure there is sufficient space to access fixed members of xlog_op_header.