From: Junio C Hamano Date: Wed, 28 Jul 2021 21:29:01 GMT Subject: Re: [PATCH v6 3/9] ssh signing: retrieve a default key from ssh-agent Message-ID: In-Reply-To: <071e6173d8e418349d94fea97624e8cee9f1dde5.1627501009.git.gitgitgadget@gmail.com> "Fabian Stelzer via GitGitGadget" writes: > From: Fabian Stelzer > > if user.signingkey is not set and a ssh signature is requested we call > ssh-add -L and use the first key we get > > Signed-off-by: Fabian Stelzer > --- > gpg-interface.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) I would have expected that this also would become a method call into *use_format object (instead of dispatching on use_format->name), but let's not go overboard. I think this is good enough for now. > diff --git a/gpg-interface.c b/gpg-interface.c > index c131977b347..3afacb48900 100644 > --- a/gpg-interface.c > +++ b/gpg-interface.c > @@ -470,11 +470,35 @@ int git_gpg_config(const char *var, const char *value, void *cb) > return 0; > } > > +/* Returns the first public key from an ssh-agent to use for signing */ > +static char *get_default_ssh_signing_key(void) > +{ > + struct child_process ssh_add = CHILD_PROCESS_INIT; > + int ret = -1; > + struct strbuf key_stdout = STRBUF_INIT; > + struct strbuf **keys; > + > + strvec_pushl(&ssh_add.args, "ssh-add", "-L", NULL); > + ret = pipe_command(&ssh_add, NULL, 0, &key_stdout, 0, NULL, 0); > + if (!ret) { > + keys = strbuf_split_max(&key_stdout, '\n', 2); > + if (keys[0]) > + return strbuf_detach(keys[0], NULL); > + } > + > + strbuf_release(&key_stdout); > + return ""; > +} > + > const char *get_signing_key(void) > { > if (configured_signing_key) > return configured_signing_key; > - return git_committer_info(IDENT_STRICT|IDENT_NO_DATE); > + if (!strcmp(use_format->name, "ssh")) { > + return get_default_ssh_signing_key(); > + } else { > + return git_committer_info(IDENT_STRICT | IDENT_NO_DATE); > + } > } > > int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)