Re: [Ksummit-discuss] [PATCH] media: add a subsystem profile documentation

[Kees Cook <keescook@chromium.org>]

On Thu, Sep 26, 2019 at 08:14:03AM -0700, Joe Perches wrote:
> On Wed, 2019-09-25 at 11:40 -0700, Kees Cook wrote:
> > Is "6" a safe lower bound here? I thought 12 was the way to go?
> []
> > $ git log | egrep 'Fixes: [a-f0-9]{1,40}' | col2 | awk '{print length }' | sort | uniq -c | sort -n | tail
> >     238 8
> >     300 7
> >     330 14
> >     344 6
> >     352 11
> >     408 40
> >     425 10
> >     735 16
> >    1866 13
> >   31446 12
> > 
> > Hmpf, 6 is pretty high up there...
> 
> Yes, but your grep then col2 isn't right.
> You are counting all the 'Fixes: commit <foo>' output
> as 6 because that's the length of 'commit'.

the [a-f0-9]{1,40} already excludes "commit".

> I also think the length of the hex commit value doesn't
> matter much as it's got to be a specific single commit
> SHA1 anyway, otherwise the commit id lookup will fail.

Fail enough. We do already have 6-digit SHA1 collisions, so it seemed
like using more than 6 would be nicer? *shrug* I don't have a strong
opinion. :)

> 
> > > > @@ -1031,6 +1040,7 @@ MAINTAINER field selection options:
> > >      --roles => show roles (status:subsystem, git-signer, list, etc...)
> > >      --rolestats => show roles and statistics (commits/total_commits, %)
> > >      --file-emails => add email addresses found in -f file (default: 0 (off))
> > > +    --fixes => for patches, add signatures of commits with 'Fixes: <commit>' (default: 1 (on))
> > 
> > Should "Tested-by" and "Co-developed-by" get added to @signature_tags ?
> 
> All "<foo>-by:" signatures are added.

Ah, I'd missed where that happened. I do note that's only when
git-all-signature-types is set, which is default 0. (/me goes to add
this to his invocations...)

my $email_git_all_signature_types = 0;
...
    if ($email_git_all_signature_types) {
        $signature_pattern = "(.+?)[Bb][Yy]:";
    } else {
        $signature_pattern = "\(" . join("|", @signature_tags) . "\)";
    }

> > @commit_authors is unused?
> 
> Yes, authors are already required to sign-off so
> it's just duplicating already existing signatures.

Sure, it just seemed odd to populate it if it wasn't going to be used.

-- 
Kees Cook