From: Fabian Stelzer <fs@gigacodes.de>
Date: Thu, 06 Oct 2022 14:19:24 GMT
Subject: Re: [PATCH v2] ssh signing: return an error when signature cannot be read
Message-ID: <20221006141924.7rxj3ntq24hynj5t@fs>
In-Reply-To: <ce32d5c7-c62c-b27f-23fa-566cba65c383@dunelm.org.uk>

On 06.10.2022 14:05, Phillip Wood wrote:
>Hi Fabian
>
>On 06/10/2022 09:28, Fabian Stelzer wrote:
>>On 04.10.2022 10:01, Phillip Wood via GitGitGadget wrote:
>>>From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>>   This patch is based on maint. In the longer term the code could be
>>>   simplified by using pipes rather than tempfiles as we do for gpg.
>>>   ssh-keygen has supported reading the data to be signed from stdin and
>>>   writing the signature to stdout since it introduced signing.
>>
>>The ssh-keygen call is already using stdin for the content to sign 
>>or verify. The signature and the signing key need to be files passed 
>>as parameters to ssh-keygen. I'm not aware of any other option of 
>>providing them to it.
>
>We use stdin for the content when verifying but not when signing
>
>	strvec_pushl(&signer.args, use_format->program,
>		     "-Y", "sign",
>		     "-n", "git",
>		     "-f", ssh_signing_key_file,
>		     buffer_file->filename.buf,
>		     NULL);
>
>	sigchain_push(SIGPIPE, SIG_IGN);
>	ret = pipe_command(&signer, NULL, 0, NULL, 0, &signer_stderr, 0);
>	sigchain_pop(SIGPIPE);
>
>Note that when verifying with -Y check-novalidate there is a missing 
>call to sigchain_push(SIGPIPE, SIG_IGN) as we are passing data over 
>stdin so need to ignore SIGPIPE.
>

Hm, true. I was kinda sure it both used stdin/out. I'm short on time at the 
moment and can't really work on git stuff. But I hope i can at the end of 
the year. There's a few more todos on my list.

Cheers,
Fabian