nvi denial of service

[coypu () sdf org]

hello,

there is an exploitable flaw in virecover in nvi (as used by netbsd and
possibly others).

the gist of it:
sudo touch /myrootownedfile
touch /var/tmp/vi.recover/vi. myrootownedfile
sudo service virecover restart # may happen naturally

now /myrootownedfile is deleted by the choice of an unprivileged user.

for your convenience, attached is the patch used in netbsd and commit
messages.

(Found by Maya Rashish, fix by Christos Zoulas and Robert Elz).

Attachment: nvi.diff
Description: