The disappearing sys_call_table export.
Quoted 8 lines · Yoav Weiss
Quoted 2 lines
"That can be done manually" does not get you the check mark in
the list of features. Management wants idiot-resistant security.It has nothing to do with idiot-resistance. Why should this multi-write operation be done in kernel ? mkswap is a usermode program. mkfs is a usermode program. If you want to have a wipeswap script that copies a chunk of your
/dev/zeroto the swap, it should also be in usermode. Just run it in wherever rc file you use to swapoff.
And when I type 'swapoff' at the command line the whole scheme fails
unless I am a perfect robot sysadmin and always remember to wipe the file. This needs to 'fail safe' and it needs to be done within the kernel to be considered a working feature.
Quoted 5 lines
And when I type 'swapoff' at the command line the whole scheme fails
unless I am a perfect robot sysadmin and always remember to wipe the file. This needs to 'fail safe' and it needs to be done within the kernel to be considered a working feature.
mv /sbin/swapoff /sbin/swapoff.real
cat >/sbin/swapoff
#!/bin/sh/sbin/swapoff.real/sbin/wipeswap
^D
chmod +x /sbin/swapoff
Any system that doesn't consider this fail-safe enough, shouldn't rely on this zeroing operation even if performed by the kernel. See the URL I posted in this thread about encrypted swap.