On Wed, Jun 10, 2020 at 06:19:22PM +0200, Petr Lautrbach wrote:
> On Wed, Jun 10, 2020 at 11:56:28AM -0400, Stephen Smalley wrote:
> > On Thu, Jun 4, 2020 at 4:08 PM Stephen Smalley
> > <stephen.smalley.work@gmail.com> wrote:
> > >
> > > As reported in https://github.com/SELinuxProject/selinux/issues/248,
> > > setfiles -r (rootpath) fails when the alternate root contains a symlink
> > > that is correct relative to the alternate root but not in the current root.
> > > This is a regression introduced by commit e016502c0a26 ("libselinux: Save
> > > digest of all partial matches for directory").  Do not call statfs(2) here
> > > if acting on a symbolic link.  Unfortunately there is no lstatfs() call.
> > > Ensure that we initialize the statfs buffer always.  If the supplied
> > > file is a symlink, then we don't need to worry about the later tests of
> > > filesystem type because we wouldn't be setting the digest anyway and
> > > we are not performing a full sysfs relabel.  While here, fix the earlier
> > > test for a directory to use the correct test.
> > >
> > > Reproducer:
> > > $ mkdir /root/my-chroot && echo foo > /root/my-chroot/link-target && ln -s /link-target /root/my-chroot/symlink
> > > $ echo "/root/my-chroot/symlink" | setfiles -vFi -r /root/my-chroot -f - /etc/selinux/targeted/contexts/files/file_contexts
> > >
> > > Before:
> > > setfiles: statfs(/root/my-chroot/symlink) failed: No such file or directory
> > >
> > > After:
> > > Relabeled /root/my-chroot/symlink from unconfined_u:object_r:admin_home_t:s0 to system_u:object_r:default_t:s0
> > >
> > > Fixes: https://github.com/SELinuxProject/selinux/issues/248
> > > Fixes: e016502c0a26 ("libselinux: Save digest of all partial matches for directory")
> > > Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> > 
> > Anyone want to ack or object to this patch?
> 
> Acked-by: Petr Lautrbach <plautrba@redhat.com>

Applied.

> > > ---
> > >  libselinux/src/selinux_restorecon.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libselinux/src/selinux_restorecon.c b/libselinux/src/selinux_restorecon.c
> > > index 91dfeb66..d1ce830c 100644
> > > --- a/libselinux/src/selinux_restorecon.c
> > > +++ b/libselinux/src/selinux_restorecon.c
> > > @@ -938,7 +938,7 @@ int selinux_restorecon(const char *pathname_orig,
> > >         }
> > >
> > >         /* Skip digest if not a directory */
> > > -       if ((sb.st_mode & S_IFDIR) != S_IFDIR)
> > > +       if (!S_ISDIR(sb.st_mode))
> > >                 setrestorecondigest = false;
> > >
> > >         if (!flags.recurse) {
> > > @@ -952,7 +952,8 @@ int selinux_restorecon(const char *pathname_orig,
> > >         }
> > >
> > >         /* Obtain fs type */
> > > -       if (statfs(pathname, &sfsb) < 0) {
> > > +       memset(&sfsb, 0, sizeof sfsb);
> > > +       if (!S_ISLNK(sb.st_mode) && statfs(pathname, &sfsb) < 0) {
> > >                 selinux_log(SELINUX_ERROR,
> > >                             "statfs(%s) failed: %s\n",
> > >                             pathname, strerror(errno));
> > > --
> > > 2.23.3
> > >
> >