From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: <git@vger.kernel.org>
Cc: Eric Sunshine <sunshine@sunshineco.com>,
Denton Liu <liu.denton@gmail.com>, Jeff King <peff@peff.net>
Subject: [PATCH 0/5] Support for commits signed by multiple algorithms
Date: Mon, 11 Jan 2021 00:37:33 +0000 [thread overview]
Message-ID: <20210111003740.1319996-1-sandals@crustytoothpaste.net> (raw)
This series introduces support for verifying commits and tags signed by
multiple algorithms.
Originally, we had planned for SHA-256 tags to stuff the signature in a
header instead of using a trailing signature, and a patch to do that was
sent out in part 1/3. Unfortunately, for whatever reason, that patch
didn't make it into the master branch, and so we use trailing signatures
there.
We can't change this now, because otherwise it would be ambiguous
whether the trailing signature on a SHA-256 object was for the SHA-256
contents or whether the contents were a rewritten SHA-1 object with no
SHA-256 signature at all. To do the next best thing, let's use the
trailing signature for the preferred hash algorithm and use a header for
the other variant. This permits round-tripping, but has the downside
that tags signed with multiple algorithms can't be verified with older
versions of Git. However, signatures created with older versions of Git
continue to be accepted.
For commits, let's accept a commit that has two signatures. We
previously created the commits correctly but didn't strip the extra
header off when verifying, so our verification indicated the signature
was bad.
Both these situations allow for signing commits and tags that can be
round-tripped through both SHA-1 and SHA-256. We verify only the
signature using the current hash algorithm, since we currently don't
rewrite objects.
brian m. carlson (5):
commit: ignore additional signatures when parsing signed commits
gpg-interface: improve interface for parsing tags
commit: allow parsing arbitrary buffers with headers
ref-filter: hoist signature parsing
gpg-interface: remove other signature headers before verifying
builtin/receive-pack.c | 4 +-
builtin/tag.c | 16 ++++++--
commit.c | 82 +++++++++++++++++++++++++++-------------
commit.h | 12 +++++-
fmt-merge-msg.c | 8 ++--
gpg-interface.c | 15 +++++++-
gpg-interface.h | 9 ++++-
log-tree.c | 15 ++++----
ref-filter.c | 23 +++++++----
t/t7004-tag.sh | 25 ++++++++++++
t/t7510-signed-commit.sh | 43 ++++++++++++++++++++-
tag.c | 15 ++++----
12 files changed, 206 insertions(+), 61 deletions(-)
next reply other threads:[~2021-01-11 0:40 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 0:37 brian m. carlson [this message]
2021-01-11 0:37 ` [PATCH 1/5] commit: ignore additional signatures when parsing signed commits brian m. carlson
2021-01-11 0:37 ` [PATCH 2/5] gpg-interface: improve interface for parsing tags brian m. carlson
2021-01-12 4:58 ` Junio C Hamano
2021-01-14 23:18 ` brian m. carlson
2021-01-15 1:47 ` Junio C Hamano
2021-01-11 0:37 ` [PATCH 3/5] commit: allow parsing arbitrary buffers with headers brian m. carlson
2021-01-11 0:37 ` [PATCH 4/5] ref-filter: hoist signature parsing brian m. carlson
2021-01-11 0:37 ` [PATCH 5/6] fixup! commit: ignore additional signatures when parsing signed commits brian m. carlson
2021-01-11 0:43 ` brian m. carlson
2021-01-11 0:37 ` [PATCH 5/5] gpg-interface: remove other signature headers before verifying brian m. carlson
2021-01-11 0:37 ` [PATCH 6/6] " brian m. carlson
2021-01-11 3:58 ` [PATCH v2 0/5] Support for commits signed by multiple algorithms brian m. carlson
2021-01-11 3:58 ` [PATCH v2 1/5] commit: ignore additional signatures when parsing signed commits brian m. carlson
2021-01-12 17:03 ` SZEDER Gábor
2021-01-11 3:58 ` [PATCH v2 2/5] gpg-interface: improve interface for parsing tags brian m. carlson
2021-01-12 5:24 ` Junio C Hamano
2021-01-11 3:58 ` [PATCH v2 3/5] commit: allow parsing arbitrary buffers with headers brian m. carlson
2021-01-11 3:58 ` [PATCH v2 4/5] ref-filter: hoist signature parsing brian m. carlson
2021-01-11 3:58 ` [PATCH v2 5/5] gpg-interface: remove other signature headers before verifying brian m. carlson
2021-01-11 22:16 ` [PATCH v2 0/5] Support for commits signed by multiple algorithms Junio C Hamano
2021-01-11 23:29 ` brian m. carlson
2021-01-12 2:03 ` Junio C Hamano
2021-01-12 2:24 ` brian m. carlson
2021-01-18 23:49 ` [PATCH v3 0/6] " brian m. carlson
2021-01-18 23:49 ` [PATCH v3 1/6] ref-filter: switch some uses of unsigned long to size_t brian m. carlson
2021-01-18 23:49 ` [PATCH v3 2/6] commit: ignore additional signatures when parsing signed commits brian m. carlson
2021-01-18 23:49 ` [PATCH v3 3/6] gpg-interface: improve interface for parsing tags brian m. carlson
2021-01-18 23:49 ` [PATCH v3 4/6] commit: allow parsing arbitrary buffers with headers brian m. carlson
2021-01-18 23:49 ` [PATCH v3 5/6] ref-filter: hoist signature parsing brian m. carlson
2021-01-18 23:49 ` [PATCH v3 6/6] gpg-interface: remove other signature headers before verifying brian m. carlson
2021-02-11 2:08 ` [PATCH v4 0/6] Support for commits signed by multiple algorithms brian m. carlson
2021-02-11 2:08 ` [PATCH v4 1/6] ref-filter: switch some uses of unsigned long to size_t brian m. carlson
2021-02-11 2:08 ` [PATCH v4 2/6] commit: ignore additional signatures when parsing signed commits brian m. carlson
2021-02-11 2:08 ` [PATCH v4 3/6] gpg-interface: improve interface for parsing tags brian m. carlson
2021-02-11 2:08 ` [PATCH v4 4/6] commit: allow parsing arbitrary buffers with headers brian m. carlson
2021-02-11 2:08 ` [PATCH v4 5/6] ref-filter: hoist signature parsing brian m. carlson
2021-02-11 2:08 ` [PATCH v4 6/6] gpg-interface: remove other signature headers before verifying brian m. carlson
2021-02-11 7:45 ` [PATCH v4 0/6] Support for commits signed by multiple algorithms Junio C Hamano
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