From: Fabian Stelzer <fs@gigacodes.de>
To: Junio C Hamano <gitster@pobox.com>,
Fabian Stelzer via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, "Han-Wen Nienhuys" <hanwen@google.com>,
"brian m. carlson" <sandals@crustytoothpaste.net>,
"Randall S. Becker" <rsbecker@nexbridge.com>,
"Bagas Sanjaya" <bagasdotme@gmail.com>,
"Hans Jerry Illikainen" <hji@dyntopia.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Felipe Contreras" <felipe.contreras@gmail.com>,
"Eric Sunshine" <sunshine@sunshineco.com>,
"Gwyneth Morgan" <gwymor@tilde.club>
Subject: Re: [PATCH v6 5/9] ssh signing: parse ssh-keygen output and verify signatures
Date: Thu, 29 Jul 2021 11:12:27 +0200 [thread overview]
Message-ID: <54671c83-4b1f-5e24-a6ad-226a4f45f952@gigacodes.de> (raw)
In-Reply-To: <xmqq35ry85or.fsf@gitster.g>
On 28.07.21 23:55, Junio C Hamano wrote:
> "Fabian Stelzer via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
>> From: Fabian Stelzer <fs@gigacodes.de>
>>
>> to verify a ssh signature we first call ssh-keygen -Y find-principal to
>
> "to" -> "To".
fixed
[snip]
>> + /*
>> + * ssh-keysign output should be:
>> + * Good "git" signature for PRINCIPAL with RSA key SHA256:FINGERPRINT
>> + * Good "git" signature for PRINCIPAL WITH WHITESPACE with RSA key SHA256:FINGERPRINT
>
> A bit unfortunate line that is overly long. These two are not
> mutually exclusive two different choices, but one is a special case
> of the other, no? How about phrasing it like so instead?
>
> /*
> * ssh-keysign output should be:
> * Good "git" signature for PRINCIPAL with RSA key SHA256:FINGERPRINT
> *
> * or for valid but unknown keys:
> * Good "git" signature with RSA key SHA256:FINGERPRINT
> *
> * Note that "PRINCIPAL" can contain whitespace, "RSA" and
> * "SHA256" part could be a different token that names of
> * the algorithms used, and "FINGERPRINT" is a hexadecimal
> * string. By finding the last occurence of " with ", we can
> * reliably parse out the PRINCIPAL.
> */
>
Yes, it's a special case that makes it a bit harder to parse. I will
change the comment like you suggested. That makes it clear.
>> + /* Search for the last "with" to get the full principal */
>> + principal = line;
>> + do {
>> + search = strstr(line, " with ");
>> + if (search)
>> + line = search + 1;
>> + } while (search != NULL);
>> + sigc->signer = xmemdupz(principal, line - principal - 1);
>> + sigc->fingerprint = xstrdup(strstr(line, "key") + 4);
>
> OK. This does not care the "RSA" part, which is future resistant.
> It assumes the <algo>:<fingerprint> comes after literal " key ",
> which I think is a reasonable thing to do.
>
> However, we never checked if the line has "key" in it, so
> strstr(line, "key") + 4 may not be pointing at where this code
> expects.
>
Hmm. What would i do if i don't find "key"? Still mark the signature as
valid an just leave fingerprint & key empty?
>> + /* We found principals - Try with each until we find a
>> + * match */
>
> /*
> * Do not forget our multi-line comment
> * style, please.
> */
>
fixed. clang-format wordwrapped those :/
>> +
>> + ret &= starts_with(ssh_keygen_out.buf, "Good");
>
> This is somewhat unusual construct in our codebase, I suspect. And
> probably is even wrong. Didn't you mean
>
> if (!ret)
> ret = starts_with(...);
>
> instead? Surely, when pipe_command() failed, it is likely that
> ssh_keygen_out may not have anything useful, and checking what the
> first up-to-four bytes of it contain unconditionally may be cheap
> enough, but the person reading the code would expect you to peek
> into the result only when you actually got the result, no?
you are correct. we don't need to look at the output when the command fails.
>
>> + if (ret == 0)
>> + break;
>
> It's more common to do
>
> if (!ret)
> break;
>
changed.
Thanks
next prev parent reply other threads:[~2021-07-29 9:12 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-06 8:19 [PATCH] Add commit & tag signing/verification via SSH keys using ssh-keygen Fabian Stelzer via GitGitGadget
2021-07-06 10:07 ` Han-Wen Nienhuys
2021-07-06 11:23 ` Fabian Stelzer
2021-07-06 14:44 ` brian m. carlson
2021-07-06 15:33 ` Fabian Stelzer
2021-07-06 15:04 ` Junio C Hamano
2021-07-06 15:45 ` Fabian Stelzer
2021-07-06 17:55 ` Junio C Hamano
2021-07-06 19:39 ` Randall S. Becker
2021-07-07 6:26 ` Bagas Sanjaya
2021-07-07 8:48 ` Fabian Stelzer
2021-07-12 12:19 ` [PATCH v2] Add commit, tag & push " Fabian Stelzer via GitGitGadget
2021-07-12 16:55 ` Ævar Arnfjörð Bjarmason
2021-07-12 20:35 ` Fabian Stelzer
2021-07-12 21:16 ` Felipe Contreras
2021-07-14 12:10 ` [PATCH v3 0/9] RFC: Add commit & tag " Fabian Stelzer via GitGitGadget
2021-07-14 12:10 ` [PATCH v3 1/9] Add commit, tag & push signing via SSH keys Fabian Stelzer via GitGitGadget
2021-07-14 18:19 ` Junio C Hamano
2021-07-14 23:57 ` Eric Sunshine
2021-07-15 8:20 ` Fabian Stelzer
2021-07-14 12:10 ` [PATCH v3 2/9] ssh signing: add documentation Fabian Stelzer via GitGitGadget
2021-07-14 20:07 ` Junio C Hamano
2021-07-15 8:48 ` Fabian Stelzer
2021-07-15 10:43 ` Bagas Sanjaya
2021-07-15 16:29 ` Junio C Hamano
2021-07-14 12:10 ` [PATCH v3 3/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-07-14 20:20 ` Junio C Hamano
2021-07-15 7:49 ` Han-Wen Nienhuys
2021-07-15 8:06 ` Fabian Stelzer
2021-07-15 8:13 ` Fabian Stelzer
2021-07-14 12:10 ` [PATCH v3 4/9] ssh signing: sign using either gpg or ssh keys Fabian Stelzer via GitGitGadget
2021-07-14 20:32 ` Junio C Hamano
2021-07-15 8:28 ` Fabian Stelzer
2021-07-14 12:10 ` [PATCH v3 5/9] ssh signing: provide a textual representation of the signing key Fabian Stelzer via GitGitGadget
2021-07-14 12:10 ` [PATCH v3 6/9] ssh signing: parse ssh-keygen output and verify signatures Fabian Stelzer via GitGitGadget
2021-07-16 0:07 ` Gwyneth Morgan
2021-07-16 7:00 ` Fabian Stelzer
2021-07-14 12:10 ` [PATCH v3 7/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-07-14 12:10 ` [PATCH v3 8/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-07-14 12:10 ` [PATCH v3 9/9] ssh signing: add more tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 1/9] ssh signing: preliminary refactoring and clean-up Fabian Stelzer via GitGitGadget
2021-07-19 23:07 ` Junio C Hamano
2021-07-19 13:33 ` [PATCH v4 2/9] ssh signing: add ssh signature format and signing using ssh keys Fabian Stelzer via GitGitGadget
2021-07-19 23:53 ` Junio C Hamano
2021-07-20 12:26 ` Fabian Stelzer
2021-07-19 13:33 ` [PATCH v4 3/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 4/9] ssh signing: provide a textual representation of the signing key Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 5/9] ssh signing: parse ssh-keygen output and verify signatures Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 6/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 7/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 8/9] ssh signing: add more tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-07-19 13:33 ` [PATCH v4 9/9] ssh signing: add documentation Fabian Stelzer via GitGitGadget
2021-07-20 0:38 ` [PATCH v4 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Junio C Hamano
2021-07-27 13:15 ` [PATCH v5 " Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 1/9] ssh signing: preliminary refactoring and clean-up Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 2/9] ssh signing: add ssh signature format and signing using ssh keys Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 3/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 4/9] ssh signing: provide a textual representation of the signing key Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 5/9] ssh signing: parse ssh-keygen output and verify signatures Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 6/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 7/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 8/9] ssh signing: add more tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-07-27 13:15 ` [PATCH v5 9/9] ssh signing: add documentation Fabian Stelzer via GitGitGadget
2021-07-28 19:36 ` [PATCH v6 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Fabian Stelzer via GitGitGadget
2021-07-28 19:36 ` [PATCH v6 1/9] ssh signing: preliminary refactoring and clean-up Fabian Stelzer via GitGitGadget
2021-07-28 22:32 ` Jonathan Tan
2021-07-29 0:58 ` Junio C Hamano
2021-07-29 7:44 ` Fabian Stelzer
2021-07-29 8:43 ` Fabian Stelzer
2021-07-28 19:36 ` [PATCH v6 2/9] ssh signing: add ssh signature format and signing using ssh keys Fabian Stelzer via GitGitGadget
2021-07-28 22:45 ` Jonathan Tan
2021-07-29 1:01 ` Junio C Hamano
2021-07-29 11:01 ` Fabian Stelzer
2021-07-29 19:09 ` Josh Steadmon
2021-07-29 21:25 ` Fabian Stelzer
2021-07-28 19:36 ` [PATCH v6 3/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-07-28 21:29 ` Junio C Hamano
2021-07-28 22:48 ` Jonathan Tan
2021-07-29 8:59 ` Fabian Stelzer
2021-07-29 19:09 ` Josh Steadmon
2021-07-29 19:56 ` Junio C Hamano
2021-07-29 21:21 ` Fabian Stelzer
2021-07-28 19:36 ` [PATCH v6 4/9] ssh signing: provide a textual representation of the signing key Fabian Stelzer via GitGitGadget
2021-07-28 21:34 ` Junio C Hamano
2021-07-29 8:21 ` Fabian Stelzer
2021-07-28 19:36 ` [PATCH v6 5/9] ssh signing: parse ssh-keygen output and verify signatures Fabian Stelzer via GitGitGadget
2021-07-28 21:55 ` Junio C Hamano
2021-07-29 9:12 ` Fabian Stelzer [this message]
2021-07-29 20:43 ` Junio C Hamano
2021-07-28 23:04 ` Jonathan Tan
2021-07-29 9:48 ` Fabian Stelzer
2021-07-29 13:52 ` Fabian Stelzer
2021-08-03 7:43 ` Fabian Stelzer
2021-08-03 9:33 ` Fabian Stelzer
2021-07-29 20:46 ` Junio C Hamano
2021-07-29 21:01 ` Randall S. Becker
2021-07-29 21:12 ` Fabian Stelzer
2021-07-29 21:25 ` Randall S. Becker
2021-07-29 21:28 ` Fabian Stelzer
2021-07-29 22:28 ` Randall S. Becker
2021-07-30 8:17 ` Fabian Stelzer
2021-07-30 14:26 ` Randall S. Becker
2021-07-30 14:32 ` Fabian Stelzer
2021-07-30 15:05 ` Randall S. Becker
2021-07-28 19:36 ` [PATCH v6 6/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-07-29 19:09 ` Josh Steadmon
2021-07-29 19:57 ` Junio C Hamano
2021-07-30 7:32 ` Fabian Stelzer
2021-07-28 19:36 ` [PATCH v6 7/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-07-28 19:36 ` [PATCH v6 8/9] ssh signing: add more tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-07-28 19:36 ` [PATCH v6 9/9] ssh signing: add documentation Fabian Stelzer via GitGitGadget
2021-07-29 8:19 ` [PATCH v6 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Bagas Sanjaya
2021-07-29 11:03 ` Fabian Stelzer
2021-08-03 13:45 ` [PATCH v7 " Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 1/9] ssh signing: preliminary refactoring and clean-up Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 2/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 3/9] ssh signing: add ssh key format and signing code Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 4/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 5/9] ssh signing: provide a textual signing_key_id Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 6/9] ssh signing: verify signatures using ssh-keygen Fabian Stelzer via GitGitGadget
2021-08-03 23:47 ` Junio C Hamano
2021-08-04 9:01 ` Fabian Stelzer
2021-08-04 17:32 ` Junio C Hamano
2021-08-03 13:45 ` [PATCH v7 7/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 8/9] ssh signing: tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-08-03 13:45 ` [PATCH v7 9/9] ssh signing: test that gpg fails for unkown keys Fabian Stelzer via GitGitGadget
2021-08-29 22:15 ` [PATCH v7 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Junio C Hamano
2021-08-29 23:56 ` Gwyneth Morgan
2021-08-30 10:35 ` Fabian Stelzer
2021-09-07 17:35 ` Junio C Hamano
2021-09-10 8:03 ` Fabian Stelzer
2021-09-10 18:44 ` Junio C Hamano
2021-09-10 19:49 ` Fabian Stelzer
2021-09-10 20:20 ` Carlo Arenas
2021-09-10 20:07 ` [PATCH v8 " Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 1/9] ssh signing: preliminary refactoring and clean-up Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 2/9] ssh signing: add test prereqs Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 3/9] ssh signing: add ssh key format and signing code Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 4/9] ssh signing: retrieve a default key from ssh-agent Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 5/9] ssh signing: provide a textual signing_key_id Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 6/9] ssh signing: verify signatures using ssh-keygen Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 7/9] ssh signing: duplicate t7510 tests for commits Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 8/9] ssh signing: tests for logs, tags & push certs Fabian Stelzer via GitGitGadget
2021-09-10 20:07 ` [PATCH v8 9/9] ssh signing: test that gpg fails for unknown keys Fabian Stelzer via GitGitGadget
2021-12-22 3:18 ` t7510-signed-commit.sh hangs on old gpg, regression in 1bfb57f642d (was: [PATCH v8 9/9] ssh signing: test that gpg fails for unknown keys) Ævar Arnfjörð Bjarmason
2021-12-22 10:13 ` Fabian Stelzer
2021-12-22 15:58 ` brian m. carlson
2021-12-26 22:53 ` Ævar Arnfjörð Bjarmason
2021-12-30 11:10 ` Fabian Stelzer
2021-09-10 20:23 ` [PATCH v8 0/9] ssh signing: Add commit & tag signing/verification via SSH keys using ssh-keygen Junio C Hamano
2021-09-10 20:48 ` Fabian Stelzer
2021-09-10 21:01 ` Junio C Hamano
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