tags 369626 + confirmed Andreas Bombe <[EMAIL PROTECTED]> writes:
> The session cleanup in 10mount ignores failures of umount invocations
> and cleanup continues. In the case of file chroots with a /home bind
> mount that failed to umount, the rm -rf in 05file blindly descends into
> the system /home with obvious unpretty results.
I'm awfully sorry if this caused you to lose any data.
> The bind mount may fail to umount whenever something gets mounted under
> the bind. In my case I was foolishly trying to rbind instead of bind
> /home in 10mount because my $HOME is a separate mount, and I wanted to
> have it available in the chroot.
I would like to use rbind, but this currently unsupported. Please see
#354344 and #354298.
> Apart from making a failed umount abort the session cleanup, I see as
> another possible solution to rm -rf only a bind mount of the chroot to
> be sure there are no sub mounts, then umount this and only rmdir the
> actual chroot. This would fail harmlessly if umounts failed (results
> only in a leftover session to be manually cleaned up).
There are a few possibilities here.
1) 10mount should exit with an error if umount fails.
Caveat: if the session is ended with the setup scripts having
failed, this would require manual cleanup by the system admin.
This needs additional work in session::setup_chroot() in
sbuild-session.cc, so that the session is not ended if the scripts
fail. This means not removing the session file from
/var/lib/schroot/session/ on failure.
Currently, because of the above consideration, the "setup-stop"
phase of the session scripts can not fail.
2) 05file must check if any filesystems are mounted under the chroot
root before running rm -rf. Is there a portable and reliable way
of doing this? Would
if mount | grep "$CHROOT_MOUNT_LOCATION"; then
:
else
rm -rf "$CHROOT_MOUNT_LOCATION" || true
fi
be sufficient?
Due to the seriousness of the problem, I think both protective
measures should be implemented.
Regards,
Roger
--
Roger Leigh
Printing on GNU/Linux? http://gutenprint.sourceforge.net/
Debian GNU/Linux http://www.debian.org/
GPG Public Key: 0x25BFB848. Please sign and encrypt your mail.
pgptZb63nT3hW.pgp
Description: PGP signature
