(Resending without HTML...)
On Fri, Sep 16, 2022 at 5:37 PM Christian Göttsche
<cgzones@xxxxxxxxxxxxxx> wrote:
>
> On Fri, 16 Sept 2022 at 16:14, 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.
> >
> > This patch changes the location where `fixfiles` mounts fs to /run and
> > adds a handler for exit signals which tries to umount fs mounted by
> > `fixfiles`.
>
> What about additionally using mount namespaces, if available:
What benefit would it bring? (Sorry, I'm not very familiar with mount
namespaces.)
>
> @@ -256,10 +256,16 @@
> test -z ${TMP_MOUNT+x} && echo "Unable to find
> temporary directory!" && exit 1
>
> mkdir -p "${TMP_MOUNT}${m}" || exit 1
> - mount --bind "${m}" "${TMP_MOUNT}${m}" || exit 1
> - ${SETFILES} ${VERBOSE} ${EXCLUDEDIRS} ${FORCEFLAG}
> ${THREADS} $* -q ${FC} -r "${TMP_MOUNT}" "${TMP_MOUNT}${m}"
> - umount "${TMP_MOUNT}${m}" || exit 1
> - rm -rf "${TMP_MOUNT}" || echo "Error cleaning up."
> + if ! unshare --mount /bin/sh -c "mount --bind
> \"${m}\" \"${TMP_MOUNT}${m}\" || exit 1 && ${SETFILES} ${VERBOSE}
> ${EXCLUDEDIRS} ${FORCEFLAG} ${THREADS} $* -q ${FC} -r \"${TMP_MOUNT}\"
> \"${TMP_MOUNT}${m}\" || true"; then
> + echo "Creating new mount namespace failed,
> operating in root namespace"
> + mount --bind "${m}" "${TMP_MOUNT}${m}" || exit 1
> + ${SETFILES} ${VERBOSE} ${EXCLUDEDIRS}
> ${FORCEFLAG} ${THREADS} $* -q ${FC} -r "${TMP_MOUNT}"
> "${TMP_MOUNT}${m}"
> + umount "${TMP_MOUNT}${m}" || exit 1
> + fi
> + if [ "${m}" != '/' ]; then
> + rmdir "${TMP_MOUNT}${m}" || echo "Error
> cleaning up ${TMP_MOUNT}${m}."
> + fi
> + rmdir "${TMP_MOUNT}" || echo "Error cleaning
> up ${TMP_MOUNT}."
> done;
> fi
> else
>
> ?
>
> >
> > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2125355
> >
> > Signed-off-by: Petr Lautrbach <plautrba@xxxxxxxxxx>
> > ---
> > v2:
> >
> > - set trap on EXIT instead of SIGINT
> >
> > v3:
> >
> > - use /run instead of /tmp for mountpoints
> >
> >
> > policycoreutils/scripts/fixfiles | 13 ++++++++++++-
> > 1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/policycoreutils/scripts/fixfiles b/policycoreutils/scripts/fixfiles
> > index c72ca0eb9d61..acf5f0996c19 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 "${TMP_MOUNT}" || echo "Error cleaning up."
> > + fi
> > + exit 130
> > +}
> > +
> > #
> > # restore
> > # if called with -n will only check file context
> > @@ -251,8 +260,9 @@ case "$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 EXIT
> > for m in `echo $FILESYSTEMSRW`; do
> > - TMP_MOUNT="$(mktemp -d)"
> > + TMP_MOUNT="$(mktemp -p /run -d fixfiles.XXXXXXXXXX)"
> > test -z ${TMP_MOUNT+x} && echo "Unable to find temporary directory!" && exit 1
> >
> > mkdir -p "${TMP_MOUNT}${m}" || exit 1
> > @@ -261,6 +271,7 @@ case "$RESTORE_MODE" in
> > umount "${TMP_MOUNT}${m}" || exit 1
> > rm -rf "${TMP_MOUNT}" || echo "Error cleaning up."
> > done;
> > + trap EXIT
> > fi
> > else
> > echo >&2 "fixfiles: No suitable file systems found"
> > --
> > 2.37.3
> >
>
--
Ondrej Mosnacek
Senior Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.
