[OE-core] [PATCH 0/4] Reproducible binaries

[Martin Jansa]

Is using the last commit really that useful?

I would like to be able to compare 2 subsequent builds (ideally performed
on 2 different hosts with some small modification in metadata layers) and
the binaries not affected by those small metadata modifications should be
the same - which is not the case if we feed them with the top commit date.

The real world use-case is that we're doing daily official builds (which
don't use sstate for some bad reasons) and just comparing
files-in-image.txt file from buildhistory shows that almost all binaries
are different every day (just their size fluctuating +- 2 bytes from the
linker mangling) and when something goes wrong, it's hard to find "the
significant diff" when it's always all different even when the 2nd build
only had very small change in image recipe.

On Tue, Apr 25, 2017 at 8:14 PM, Juro Bystricky <juro.bystricky at intel.com>
wrote:

> This patch set contains several patches aimed to achieve reproducible
> binaries.
> Building reproducible binaries may remove certain intentional
> randomness intended for increased security. Hence, it is reasonable
> to expect there will be cases where this is not desirable.
> The user can select his/her preferences via the variable
> BUILD_REPRODUCIBLE_BINARIES. The variable defaults to "0" (do not
> build reproducible binaries) in order to minimize any potential
> regressions. (Once the reproducible binaries code is mature enough,
> it can be set to "1".)
>
> The patch set is rather simple, targeting the "low hanging fruit".
> For debian packages we get a lot of binary identical packages simply by
> exporting SOURCE_DATE_EPOCH.
> For rootfs we get much fewer differences by modified prelinking and by
> ensuring various timestamps are reproducible.
>
>
> Juro Bystricky (4):
>   bitbake.conf: new variable BUILD_REPRODUCIBLE_BINARIES
>   base.bbclass: initial support for binary reproducibility
>   image-preling.bbclass: support binary reproducibility
>   rootfs-postcommands.bbclass: support binary reproducibility
>
>  meta/classes/base.bbclass                | 82
> ++++++++++++++++++++++++++++++++
>  meta/classes/image-prelink.bbclass       |  9 +++-
>  meta/classes/rootfs-postcommands.bbclass | 18 ++++++-
>  meta/conf/bitbake.conf                   |  3 ++
>  4 files changed, 109 insertions(+), 3 deletions(-)
>
> --
> 2.7.4
>
> --
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