feat(handler): add support for minix filesystems

[jstucke]

• little endian test files were created with mkfs.minix
  • since there does not seem to be a tool to create big endian MINIX filesystems, those test files were created by byte swapping the little endian test files
• known firmware samples with MINIX FS:
  • Trendnet IP cameras, e.g. TV-IP110W and TV-IP422WN (both MINIX FS v1 LE with 30 byte filenames)
  • Netgear switches, e.g. FSM7326P and GSM7248 (both MINIX FS v2 BE with 30 byte filenames)
  • I have not encountered MINIX v3 filesystems in firmware images, but adding it anyway was little overhead

[jstucke]

hmm I noticed that I should probably add a few sanity checks to calculate_chunk to avoid false positives

[qkaiser]

First review pass over lunch, will get back with a more detailed review.

[qkaiser]

@jstucke your recent contributions are highly appreciated. Keep them coming ! :)

[jstucke]

@jstucke your recent contributions are highly appreciated. Keep them coming ! :)

Haha thank you for taking the time for a thorough review. I added some validity checks and tests with invalid headers. I also found the original tool from the minix project and was also able to create samples with block size > 1024 and even log_zone_size != 0 (which is not possible with the mkfs.minix included in linux), but sadly I am unable to mount the filesystems and therefore could not add any files. The validity checks seem to work, though. There is are some images on the minix download page which uses v3 with blocksize 4096 and it seems to be unpacked without problems.

I will probably fix the remaining issues tomorrow.

[qkaiser]

@jstucke I'll do some cleanups on this branch sometimes this week, but not sure when. Hang on :)

[qkaiser]

Cleaning up the code and doing cross-validation as we speak. Will push my changes when I'm done.

[qkaiser]

Cleaning up the code and doing cross-validation as we speak. Will push my changes when I'm done.

@jstucke Still ongoing, will keep you posted.