Experiments with sswap(1), srm(1), wipe(1), gdisk(8), lsblk and gpart(8)
Date: Fri, 27 Aug 2021 14:59:27 UTC
On 27/08/2021 12:22, Graham Perrin wrote: > … sswap(1) to securely delete whatever might be there. … I took an opportunity to experiment with some of the other utilities that were recently installed by security/secure_delete and security/wipe. All new to me. With reference to the attached file, a few points of interest. Some of it's PEBKAM, I don't mind sharing my mistakes. I'll report what might be an obscure bug in lsblk. ---- Line 5, misuse of srm – `srm -lv /dev/da0p3` – was followed by peculiar output from a run of lsblk. No surprise there. Lines 131–139, gdisk should have added freebsd-swap at /dev/da0p3, I ignored the suggestion to remove the hard disk drive ("Warning: The kernel may continue to use old or deleted partitions."), gpart then showed nothing (free space) where da0p3 was expected. Line 152, I used gpart to add freebsd-swap at da0p3. Lines 288–297, gdisk should have deleted /dev/da0p3, I ignored the suggestion to remove the drive, lsblk showed da0p3 still present. Lines 301–359, tail of /var/log/messages whilst I disconnected then reconnected the multi-purpose dock in which the drive was seated. Line 375, with nothing in the SD card reader at da0, lsblk showed freebsd-swap. Lines 379–383, with the hard disk drive at da4, lsblk showed nothing (free space) between da4p2 and da4p4 – the preceding deletion by gdisk was a success. Lines 418–430, gdisk succesfully added freebsd-swap at /dev/da4p3 – the partition was detected by lsblk _without_ the need to disconnect then reconnect the dock. ---- I disconnected then reconnected the dock, lsblk continues to show what I might describe as a 'ghost' where truly there's nothing in the SD card reader at da0. da0, where previously there was the hard disk drive on the JMicron USB to ATA/ATAPI bridge.