On Wed, Sep 7, 2011 at 13:57, Junio C Hamano <gitster@xxxxxxxxx> wrote:
> If a tag is GPG-signed, and if you trust the cryptographic robustness of
> the SHA-1 and GPG, you can guarantee that all the history leading to the
> signed commit is not tampered with. However, it would be both cumbersome
> and cluttering to sign each and every commit. Especially if you strive to
> keep your history clean by tweaking, rewriting and polishing your commits
> before pushing the resulting history out, many commits you will create
> locally end up not mattering at all, and it is a waste of time to sign
> them.
>
> A better alternative could be to sign a "push certificate" (for the lack
> of better name) every time you push, asserting that what commits you are
> pushing to update which refs. The basic workflow goes like this:
>
> 1. You push out your work with "git push -s";
Yay!
> And here is a skeleton to implement it. It has all the necessary protocol
> extensions implemented (although I do not know if we need separate
> codepath for stateless RPC mode), but does not have subroutines to:
Yea, its broken for stateless RPC. See below.
> +static char *receive_push_certificate(void)
> +{
> + struct strbuf cert = STRBUF_INIT;
> + for (;;) {
> + char line[1000];
1000 isn't enough for some certificates. Imagine pushing a Gerrit Code
Review managed repository with 2M worth of advertisement data at once.
You can't sign that in 1000 bytes.
> @@ -326,6 +366,23 @@ int send_pack(struct send_pack_args *args,
> safe_write(out, req_buf.buf, req_buf.len);
> packet_flush(out);
> }
> +
> + if (signed_push) {
> + char *cp, *ep;
> +
> + sign_push_certificate(&push_cert);
> + strbuf_reset(&req_buf);
> + for (cp = push_cert.buf; *cp; cp = ep) {
> + ep = strchrnul(cp, '\n');
> + if (*ep == '\n')
> + ep++;
> + packet_buf_write(&req_buf, "%.*s",
> + (int)(ep - cp), cp);
> + }
> + /* Do we need anything funky for stateless rpc? */
Yes. Above we flushed the req_buf and send that in an HTTP request.
You need to hoist this block above the "if (args->stateless_rpc)"
segment.
--
Shawn.
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