Crash when lseek-ing on openafs proc node

[Ian Wienand]

Hi,

Our application makes openafs ioctl calls with Python, which eventually through os.open() does an lseek under the hood. The full issue is explained at [1], but e.g. a simple reproducer is

python3 -c 'open("/proc/fs/openafs/afs_ioctl", mode="rb", buffering=4096)

Currently this causes a null-dereference oops. This was fixed upstream with commit [2].

This hasn't made it into any openafs release (it was proposed in March 2022 but only committed Jan 2023), but I think it is a candidate for backport into the 1.8.8 packages to avoid this problem.

Thank you

-i

[1] https://review.opendev.org/c/zuul/zuul/+/885298
[2] https://git.openafs.org/?p=openafs.git;a=commit;h=68851b782ca2cb5e4ae7457255841f44f3bef15c