unreproducible builds from go_normal_opts.mk

[bmwiedemann]

While working on reproducible builds for openSUSE, I found that
our apptainer varies between builds in its build-id from mlocal/frags/go_normal_opts.mk use of urandom. Dropping that line, makes builds reproducible.

36f05c8 does not have much details on how this relates to stripping of symbol, so maybe you can share some thoughts.

Version of Apptainer

1.2.2

Expected behavior

It should be possible to build identical binaries twice.

Actual behavior

mlocal/frags/go_normal_opts.mk adds randomness into binaries

Steps to reproduce this behavior

How can others reproduce this issue/problem?

build twice

What OS/distro are you running

openSUSE-Tumbleweed 20230819

How did you install Apptainer

N/A

[DrDaveD]

That commit was inherited from the https://github.com/apptainer/singularity repository. If you look at the same commit there it leads to apptainer/singularity#2202 which has a little more context but not much. It does so happen that a commit that references that PR (shown at the end of that PR) has a comment that is a little more helpful:

Remove `-P release-stripped` from the `.spec.in`. PR apptainer#2202 adds
a Build ID which should make stripping unneeded.

Maybe instead of adding a random number it should use a hash of the source tarball. How does that sound?

[bmwiedemann]

If you use the source-tarball-hash, you would give the same ID to all different binaries.

It seems, that the tools already auto-assign deterministic build-ids based on input hashes:

for section in .note.go.buildid .note.gnu.build-id ; do
   objdump -s -j $section RPMS/usr/libexec/apptainer/bin/starter
done

RPMS/usr/libexec/apptainer/bin/starter:     file format elf64-x86-64

Contents of section .note.go.buildid:
 03d4 04000000 53000000 04000000 476f0000  ....S.......Go..
 03e4 456d7853 63755a67 73485043 784d3169  EmxScuZgsHPCxM1i
 03f4 6d7a3731 2f6a6355 75583435 59397851  mz71/jcUuX45Y9xQ
 0404 4279374c 4c39746c 612f4d65 4f746757  By7LL9tla/MeOtgW
 0414 6e46546d 534e5a34 4f36486f 714a2f44  nFTmSNZ4O6HoqJ/D
 0424 33345754 36673647 7242695a 4936734f  34WT6g6GrBiZI6sO
 0434 79453400                             yE4.            

RPMS/usr/libexec/apptainer/bin/starter:     file format elf64-x86-64

Contents of section .note.gnu.build-id:
 0390 04000000 14000000 03000000 474e5500  ............GNU.
 03a0 dfc15b49 8ba2ccde 9e73a2ca 5b42a423  ..[I.....s..[B.#
 03b0 53e6f495                             S...            

So I'd just drop go_normal_opts.mk.

[DrDaveD]

Please make a PR to see if it works.