Re: [PATCH] isofs: reject short directory records in isofs_read_level3_size()

[Matthias Goergens <matthias.goergens@gmail.com>]

Hi Hui,

I'm sorry, I missed your patch when I sent mine for the same function a
few days later ("[PATCH v2] isofs: validate directory records in
isofs_read_level3_size()"), and Jan has since applied mine to his tree.

I did test yours, on mainline and on Jan's for_next, running fs/isofs in
a userspace harness with ASan and UBSan: it fixes the three fuzzer
images that made isofs_read_level3_size() read past a record, and I
found no change on valid multi-extent images.

The part of yours that mine doesn't have is the limit on how many empty
blocks the walk skips.  Without it, a run of zero blocks is walked until
the end of the device.  On top of for_next that would be a small
follow-up, and if you'd like to send it I'm happy to test and review it.
If you'd rather I send it, I'll credit you with Suggested-by, or with
Co-developed-by followed by your Signed-off-by if you prefer.

Thanks,
Matthias