Re: [PATCH] fedora: Replace pasta hard links by copies, mangle Build-IDs

[Stefano Brivio <sbrivio@redhat.com>]

On Wed, 23 Aug 2023 15:31:46 +0100
"Richard W.M. Jones" <rjones@redhat.com> wrote:

> On Wed, Aug 23, 2023 at 03:59:39PM +0200, Stefano Brivio wrote:
> > On Wed, 23 Aug 2023 14:53:27 +0100
> > "Richard W.M. Jones" <rjones@redhat.com> wrote:
> >   
> > > On Wed, Aug 23, 2023 at 03:48:44PM +0200, Stefano Brivio wrote:  
> > > > The hard link trick didn't actually fix the issue with SELinux file
> > > > contexts properly: as opposed to symbolic links, SELinux now
> > > > correctly associates types to the labels that are set -- except that
> > > > those labels are now shared, so we can end up (depending on how
> > > > rpm(8) extracts the archives) with /usr/bin/passt having a
> > > > pasta_exec_t context.
> > > > 
> > > > This got rather confusing as running restorecon(8) seemed to fix up
> > > > labels -- but that's simply toggling between passt_exec_t and
> > > > pasta_exec_t for both links, because each invocation will just "fix"
> > > > the file with the mismatching context.
> > > > 
> > > > Replace the hard links with copies. AppArmor's attachment, instead,
> > > > works with hard links, and if there's no LSM, we can keep symbolic
> > > > links, so keep symbolic links in the Makefile.
> > > > 
> > > > With copies, rpmbuild(8) will warn about duplicate Build-IDs in the
> > > > same package. Mangle them in pasta binaries by summing one to the
> > > > last byte, modulo one byte, using xxd (provided by vim-common) and
> > > > disable the automatic rehashing by find-debuginfo(1) -- we already
> > > > have per-release Build-IDs thanks to $VERSION passed on 'make'.    
> > > 
> > > Right, this ^ was going to be my comment.  RPM doesn't like having two
> > > identical copies of a file.  
> > 
> > In which other way, though? cpio(1) is fine with it, and I tried to
> > install the package on both ext4 and xfs -- the only warning I got was
> > the (semi-reasonable) one from rpmbuild about duplicate Build-IDs.  
> 
> I'm fairly sure I've seen an error when you have two identical files;

...but those are not identical, exactly because I change the Build-ID.

> it might only happen in Koji.  Anyway, hacking the binary is surely
> wrong, but let's hear the opinions of the Fedora / SELinux developers.

I don't see why it would be "surely wrong".

It's surely ugly, though, and David suggested that two separate builds
might be slightly less ugly, albeit (more) wasteful, but passt takes
seconds to build, after all. New patch posted.

-- 
Stefano