Ondrej Mosnacek <omosnace@xxxxxxxxxx> writes: > On Thu, Sep 15, 2022 at 2:45 PM Petr Lautrbach <plautrba@xxxxxxxxxx> wrote: >> `fixfiles -M relabel` temporary bind mounts filestems before relabeling >> but it leaves a directory mounted in /tmp/tmp.XXXX when a user hits >> CTRL-C. It means that if the user run `fixfiles -M relabel` again and >> answered Y to clean out /tmp directory, it would remove all data from >> mounted fs. >> >> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2125355 >> >> Signed-off-by: Petr Lautrbach <plautrba@xxxxxxxxxx> >> --- >> policycoreutils/scripts/fixfiles | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/policycoreutils/scripts/fixfiles b/policycoreutils/scripts/fixfiles >> index c72ca0eb9d61..6811921970f2 100755 >> --- a/policycoreutils/scripts/fixfiles >> +++ b/policycoreutils/scripts/fixfiles >> @@ -207,6 +207,15 @@ rpm -q --qf '[%{FILESTATES} %{FILENAMES}\n]' "$1" | grep '^0 ' | cut -f2- -d ' ' >> [ ${PIPESTATUS[0]} != 0 ] && echo "$1 not found" >/dev/stderr >> } >> >> +# unmount tmp bind mount before exit >> +umount_TMP_MOUNT() { >> + if [ -n "$TMP_MOUNT" ]; then >> + umount "${TMP_MOUNT}${m}" || exit 130 >> + rm -rf "${TMP_MOUNT}" || echo "Error cleaning up." >> + fi >> + exit 130 >> +} >> + >> # >> # restore >> # if called with -n will only check file context >> @@ -251,6 +260,7 @@ case "$RESTORE_MODE" in >> else >> # we bind mount so we can fix the labels of files that have already been >> # mounted over >> + trap umount_TMP_MOUNT SIGINT >> for m in `echo $FILESYSTEMSRW`; do >> TMP_MOUNT="$(mktemp -d)" >> test -z ${TMP_MOUNT+x} && echo "Unable to find temporary directory!" && exit 1 >> @@ -261,6 +271,7 @@ case "$RESTORE_MODE" in >> umount "${TMP_MOUNT}${m}" || exit 1 >> rm -rf "${TMP_MOUNT}" || echo "Error cleaning up." >> done; >> + trap SIGINT >> fi >> else >> echo >&2 "fixfiles: No suitable file systems found" >> -- >> 2.37.3 >> > > And what if the fixfiles process is terminated via SIGTERM or even > SIGKILL? Good point. > Or a power failure occurs at the wrong time? After power failure and reboot there's no bind mountpoints from fixfiles left. > What if some > other process leaves behind a bind mount / other mount in /tmp? I don't know. But it's up to users to decide. If they are not sure, they should answer 'No' to /tmp clean up. > My suggestion would be to: > 1) Change the trap from SIGINT to EXIT. That will cover both SIGTERM and SIGINT. I'll send updated patch with this. > 2) Additionally modify fullrelabel() to not traverse across mounts > when doing the removing (+ possibly exit with an error whenever a > mountpoint is encountered - OR - try to unmount the mounts instead of > removing their contents). Given that I don't know what was the original motivation for the cleaing code and users are asked whether they want to clean up /tmp and they are warned that they would need to reboot after this operation, I'm not sure how I would defend the change. Thanks, Petr > -- > Ondrej Mosnacek > Senior Software Engineer, Linux Security - SELinux kernel > Red Hat, Inc.
