Re: [PATCH v2 1/7] fedora: Install pasta as hard link to ensure SELinux file context match

On Thu, 17 Aug 2023 08:53:55 +0100 "Richard W.M. Jones" wrote:

On Wed, Aug 16, 2023 at 08:17:24PM +0200, Stefano Brivio wrote:

...

The Makefile installs symbolic links by default, which actually worked at some point (not by design) with SELinux, but at least on recent kernel versions it doesn't anymore: override pasta (and pasta.avx2) with hard links.

Otherwise, even if the links are labeled as pasta_exec_t, SELinux will "resolve" them to passt_exec_t, and we'll have pasta running as passt_t instead of pasta_t.

Signed-off-by: Stefano Brivio --- contrib/fedora/passt.spec | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/contrib/fedora/passt.spec b/contrib/fedora/passt.spec index 8d28ef6..d0c6895 100644 --- a/contrib/fedora/passt.spec +++ b/contrib/fedora/passt.spec @@ -54,10 +54,17 @@ This package adds SELinux enforcement to passt(1) and pasta(1). %make_build VERSION="%{version}-%{release}.%{_arch}"

%install + %make_install DESTDIR=%{buildroot} prefix=%{_prefix} bindir=%{_bindir} mandir=%{_mandir} docdir=%{_docdir}/%{name} +# The Makefile creates symbolic links for pasta, but we need hard links for +# SELinux file contexts to work as intended. Same with pasta.avx2 if present. +ln -f %{buildroot}%{_bindir}/passt %{buildroot}%{_bindir}/pasta %ifarch x86_64 +ln -f %{buildroot}%{_bindir}/passt.avx2 %{buildroot}%{_bindir}/pasta.avx2 + ln -sr %{buildroot}%{_mandir}/man1/passt.1 %{buildroot}%{_mandir}/man1/passt.avx2.1 ln -sr %{buildroot}%{_mandir}/man1/pasta.1 %{buildroot}%{_mandir}/man1/pasta.avx2.1 +install -p -m 755 %{buildroot}%{_bindir}/passt.avx2 %{buildroot}%{_bindir}/pasta.avx2 %endif

Acked-by: Richard W.M. Jones

... although why not change the Makefile install rule instead so everyone gets this change?

Because that's only needed for SELinux "based" distributions. I have the feeling that symlinks are in general more desirable -- at least personally I find them less confusing. Also, David pointed out that hard links are not supported by a number of filesystems, and we probably don't want to mess this up for embedded environments. On the other hand, I didn't check yet if AppArmor would also benefit from this -- there we have at the moment a single profile for passt and pasta (the symlink behaviour is documented)... if it does, I guess it might make sense to switch to hard links in the Makefile (assuming there are no issues with other distributions), and perhaps export a Makefile variable to have symlinks instead. -- Stefano