DD bug fails to wipe last 48 sectors of a disk

[Hashim Aziz]

I first came across this bug last year, and wrote up my findings in a detailed answer to the StackExchange network:

https://superuser.com/questions/1505715/why-does-dd-give-me-an-error-at-the-end-of-zero-writing-a-disk

I didn’t then have the time to report it to this mailing list, but have just tested it using the latest version of Cygwin on the same two disks as I did then, and can confirm that the problem still persists. It’s also of note that I was running Windows 7 back then and am currently running 10, so this is now confirmed to manifest on both of the last two Windows OSes. I’m happy to work with the team to get this fixed, as I frequently need to make use of Cygwin dd to zero out drives for both security and regulatory compliance reasons, and failing to wipe the last 48 sectors of all drives is a pretty significant security risk.

Thanks,
Hashim