Re: [PATCH 1/3] merge: add config option for verifySignatures

From: Kevin Daudt <me@ikke.info>
Date: Dec 9, 2017, 12:05 UTC
Message-ID: <20171209120537.GA6006@alpha.vpn.ikke.info>
In-Reply-To: <20171209090530.6747-1-hji@dyntopia.com>

Hello Hans Jerry,

Thank you for your contribution. I have soem remarks below.

On Sat, Dec 09, 2017 at 09:05:28AM +0000, Hans Jerry Illikainen wrote:

> Verify the signature of the tip commit when `merge.verifySignatures` is
> true.  This can be overridden with `--no-verify-signatures`.
> 
> Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>

I miss the motivation in the commit message. I imagine something like:

    git merge --verify-signatures can be used to verify that the tip
    commit of the branch being merged in is properly signed, but it's
    cumbersome to have to specify that every time.
    
    Add a configuration option that enables this behaviour by default,
    which can be overridden by --no-verify-signatures.

Show 21 quoted lines

> ---
>  Documentation/merge-config.txt     |  7 +++++++
>  builtin/merge.c                    |  2 ++
>  t/t7612-merge-verify-signatures.sh | 43 ++++++++++++++++++++++++++++++++++++--
>  3 files changed, 50 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt
> index df3ea3779..76571cd3b 100644
> --- a/Documentation/merge-config.txt
> +++ b/Documentation/merge-config.txt
> @@ -26,6 +26,13 @@ merge.ff::
>  	allowed (equivalent to giving the `--ff-only` option from the
>  	command line).
>  
> +merge.verifySignatures::
> +	Verify that the tip commit of the side branch being merged is
> +	signed with a valid key, i.e. a key that has a valid uid: in the
> +	default trust model, this means the signing key has been signed
> +	by a trusted key. If the tip commit of the side branch is not
> +	signed with a valid key, the merge is aborted.
> +

This is a verbatim copy of the explenation of --verify-signatures. Would it be an idea to refer to the explenation of merge --verify-signatures?

Show 57 quoted lines

>  include::fmt-merge-msg-config.txt[]
>  
>  merge.renameLimit::
> diff --git a/builtin/merge.c b/builtin/merge.c
> index 612dd7bfb..30264cfd7 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -567,6 +567,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
>  
>  	if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
>  		show_diffstat = git_config_bool(k, v);
> +	else if (!strcmp(k, "merge.verifysignatures"))
> +		verify_signatures = git_config_bool(k, v);
>  	else if (!strcmp(k, "pull.twohead"))
>  		return git_config_string(&pull_twohead, k, v);
>  	else if (!strcmp(k, "pull.octopus"))
> diff --git a/t/t7612-merge-verify-signatures.sh b/t/t7612-merge-verify-signatures.sh
> index 8ae69a61c..f1a74a683 100755
> --- a/t/t7612-merge-verify-signatures.sh
> +++ b/t/t7612-merge-verify-signatures.sh
> @@ -39,23 +39,62 @@ test_expect_success GPG 'merge unsigned commit with verification' '
>  	test_i18ngrep "does not have a GPG signature" mergeerror
>  '
>  
> +test_expect_success GPG 'merge unsigned commit with merge.verifySignatures=true' '
> +	test_config merge.verifySignatures true &&
> +	test_must_fail git merge --ff-only side-unsigned 2>mergeerror &&
> +	test_i18ngrep "does not have a GPG signature" mergeerror
> +'
> +
>  test_expect_success GPG 'merge commit with bad signature with verification' '
>  	test_must_fail git merge --ff-only --verify-signatures $(cat forged.commit) 2>mergeerror &&
>  	test_i18ngrep "has a bad GPG signature" mergeerror
>  '
>  
> +test_expect_success GPG 'merge commit with bad signature with merge.verifySignatures=true' '
> +	test_config merge.verifySignatures true &&
> +	test_must_fail git merge --ff-only $(cat forged.commit) 2>mergeerror &&
> +	test_i18ngrep "has a bad GPG signature" mergeerror
> +'
> +
>  test_expect_success GPG 'merge commit with untrusted signature with verification' '
>  	test_must_fail git merge --ff-only --verify-signatures side-untrusted 2>mergeerror &&
>  	test_i18ngrep "has an untrusted GPG signature" mergeerror
>  '
>  
> +test_expect_success GPG 'merge commit with untrusted signature with merge.verifySignatures=true' '
> +	test_config merge.verifySignatures true &&
> +	test_must_fail git merge --ff-only side-untrusted 2>mergeerror &&
> +	test_i18ngrep "has an untrusted GPG signature" mergeerror
> +'
> +
>  test_expect_success GPG 'merge signed commit with verification' '
>  	git merge --verbose --ff-only --verify-signatures side-signed >mergeoutput &&
> -	test_i18ngrep "has a good GPG signature" mergeoutput
> +	test_i18ngrep "has a good GPG signature" mergeoutput &&
> +	git checkout initial

This looks like a clean up step. If so, it's better to add `test_when_finished 'git checkout initial'` at the beginning to clearly mark it as a clean up step and make sure it's run even when the test fails. Same counts for the other occurances.

Show 28 quoted lines

> +'
> +
> +test_expect_success GPG 'merge signed commit with merge.verifySignatures=true' '
> +	test_config merge.verifySignatures true &&
> +	git merge --verbose --ff-only side-signed >mergeoutput &&
> +	test_i18ngrep "has a good GPG signature" mergeoutput &&
> +	git checkout initial
>  '
>  
>  test_expect_success GPG 'merge commit with bad signature without verification' '
> -	git merge $(cat forged.commit)
> +	git merge $(cat forged.commit) &&
> +	git checkout initial
> +'
> +
> +test_expect_success GPG 'merge commit with bad signature with merge.verifySignatures=false' '
> +	test_config merge.verifySignatures false &&
> +	git merge $(cat forged.commit) &&
> +	git checkout initial
> +'
> +
> +test_expect_success GPG 'merge commit with bad signature with merge.verifySignatures=true and --no-verify-signatures' '
> +	test_config merge.verifySignatures true &&
> +	git merge --no-verify-signatures $(cat forged.commit) &&
> +	git checkout initial
>  '
>  
>  test_done

Kevin.