In the Linux kernel, the following vulnerability has been resolved:
xfs: add bounds checking to xlogrecoverprocess_data
There is a lack of verification of the space occupied by fixed members of xlogopheader in the xlogrecoverprocess_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 tailblk and headblk are the same, which will result in the inability to enter xlogrecoverprocessdata 3) Write a tool to parse and modify the copied image in step 2 4) Make the end of the xlogopheader entries only 1 byte away from xlogrecheader->hsize 5) xlogrecheader->hnumlogops++ 6) Modify xlogrecheader->h_crc
Fix: Add a check to make sure there is sufficient space to access fixed members of xlogopheader.