From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id C5CB21F9E5 for ; Mon, 19 Jul 2021 13:35:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238581AbhGSMwm (ORCPT ); Mon, 19 Jul 2021 08:52:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238574AbhGSMwm (ORCPT ); Mon, 19 Jul 2021 08:52:42 -0400 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B5FFC061762 for ; Mon, 19 Jul 2021 05:55:03 -0700 (PDT) Received: by mail-wr1-x433.google.com with SMTP id t5so22029345wrw.12 for ; Mon, 19 Jul 2021 06:33:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=pjPgaX5g6vxYnwbafFZ0VAs19ES/PsZ4PjB45eY3TlQ=; b=ECt2PkLCI5lk6my/bgXPwsEwfQit4ZVJt7umkMwwCYHlRKxte4PBBXBX96Ux/HLKNm 1GUMLFNJyUJyEGb+zUEk2UmYNEQbBthLPOIJwRs2Y3GuKtzG3Gqk9PEuFJk3SUdPi0bA J/bvlD7zpfT6DGRgzkY3f7lJSwZw/K4VE0BCGivP5ItX1/LrMLLgvzOdXj1IrpViQBNR llJ/i5Oqd4u65rZ/zZGQOZH2TdmyD8tlgP6YlGKWqbQ9N14Nwk1VufwIklP6NeVH5aHE zXbVqDLhH7RenxWKO0A8aDtADzdgMpH2kZVMtB8c01RG+of+RsaSv7nP0mFDz+vBAqkn tunA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=pjPgaX5g6vxYnwbafFZ0VAs19ES/PsZ4PjB45eY3TlQ=; b=LV5iOgZ22OVcLnVgqEyx7o0HzBqHH4tz7u+hhO1483sKkegzAcgdG24THoJI7+SjG5 fyS8EM5858sRIkCmzCF7G0579qx9WirK11u41DtHs3c1h761yjW9o7nlUzcTf/2WeWmG GKZukl7zZkKMPgiN20mIN2gFQ/pYdPVpe9xqxmmm+ypd6h78dPVIcDjr2/yGzHE1iWvV hpaoktCdBZ0IRVL0qktXX5QEgABlvpGi9YRH+lyDQmxWNrgd07kcqoQqDyZCjB8yBtdL iJ5hJaF9xcSSczO9iqePw7v9C0DxH7rc38twHeUY7RjW1BdVFd9PNhMdk+Zwx0BQ9TjB beeg== X-Gm-Message-State: AOAM533qimg3g7P7DWAaSUUXfRgnPeVrpgasOuTahu0u3DPp5v4E0OpB a9PxrvE0Gi5EVSl9Nt9JnLDjoS10Bew= X-Google-Smtp-Source: ABdhPJw1McqkTvF9b7I4fGDLCnfO4LWGRmW0mTwbmi7+x8QGnyON7Fpfouy//hzWahoVIyMpb38rmg== X-Received: by 2002:a5d:4fc6:: with SMTP id h6mr29969113wrw.112.1626701599610; Mon, 19 Jul 2021 06:33:19 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id v21sm19969246wml.5.2021.07.19.06.33.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jul 2021 06:33:19 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Fabian Stelzer via GitGitGadget" Date: Mon, 19 Jul 2021 13:33:08 +0000 Subject: [PATCH v4 1/9] ssh signing: preliminary refactoring and clean-up Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 To: git@vger.kernel.org Cc: Han-Wen Nienhuys , Fabian Stelzer , "brian m. carlson" , "Randall S. Becker" , Bagas Sanjaya , Hans Jerry Illikainen , =?UTF-8?Q?=C3=86var_Arnfj=C3=B6r=C3=B0?= Bjarmason , Felipe Contreras , Eric Sunshine , Gwyneth Morgan , Fabian Stelzer , Fabian Stelzer Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Fabian Stelzer Openssh v8.2p1 added some new options to ssh-keygen for signature creation and verification. These allow us to use ssh keys for git signatures easily. In our corporate environment we use PIV x509 Certs on Yubikeys for email signing/encryption and ssh keys which I think is quite common (at least for the email part). This way we can establish the correct trust for the SSH Keys without setting up a separate GPG Infrastructure (which is still quite painful for users) or implementing x509 signing support for git (which lacks good forwarding mechanisms). Using ssh agent forwarding makes this feature easily usable in todays development environments where code is often checked out in remote VMs / containers. In such a setup the keyring & revocationKeyring can be centrally generated from the x509 CA information and distributed to the users. To be able to implement new signing formats this commit: - makes the sigc structure more generic by renaming "gpg_output" to "output" - introduces function pointers in the gpg_format structure to call format specific signing and verification functions - moves format detection from verify_signed_buffer into the check_signature api function and calls the format specific verify - renames and wraps sign_buffer to handle format specific signing logic as well Signed-off-by: Fabian Stelzer --- fmt-merge-msg.c | 6 +-- gpg-interface.c | 104 +++++++++++++++++++++++++++++------------------- gpg-interface.h | 2 +- log-tree.c | 8 ++-- pretty.c | 4 +- 5 files changed, 74 insertions(+), 50 deletions(-) diff --git a/fmt-merge-msg.c b/fmt-merge-msg.c index 0f66818e0f8..fb300bb4b67 100644 --- a/fmt-merge-msg.c +++ b/fmt-merge-msg.c @@ -526,11 +526,11 @@ static void fmt_merge_msg_sigs(struct strbuf *out) buf = payload.buf; len = payload.len; if (check_signature(payload.buf, payload.len, sig.buf, - sig.len, &sigc) && - !sigc.gpg_output) + sig.len, &sigc) && + !sigc.output) strbuf_addstr(&sig, "gpg verification failed.\n"); else - strbuf_addstr(&sig, sigc.gpg_output); + strbuf_addstr(&sig, sigc.output); } signature_check_clear(&sigc); diff --git a/gpg-interface.c b/gpg-interface.c index 127aecfc2b0..31cf4ba3938 100644 --- a/gpg-interface.c +++ b/gpg-interface.c @@ -15,6 +15,12 @@ struct gpg_format { const char *program; const char **verify_args; const char **sigs; + int (*verify_signed_buffer)(struct signature_check *sigc, + struct gpg_format *fmt, const char *payload, + size_t payload_size, const char *signature, + size_t signature_size); + int (*sign_buffer)(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key); }; static const char *openpgp_verify_args[] = { @@ -35,14 +41,29 @@ static const char *x509_sigs[] = { NULL }; +static int verify_gpg_signed_buffer(struct signature_check *sigc, + struct gpg_format *fmt, const char *payload, + size_t payload_size, const char *signature, + size_t signature_size); +static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key); + static struct gpg_format gpg_format[] = { - { .name = "openpgp", .program = "gpg", - .verify_args = openpgp_verify_args, - .sigs = openpgp_sigs + { + .name = "openpgp", + .program = "gpg", + .verify_args = openpgp_verify_args, + .sigs = openpgp_sigs, + .verify_signed_buffer = verify_gpg_signed_buffer, + .sign_buffer = sign_buffer_gpg, }, - { .name = "x509", .program = "gpgsm", - .verify_args = x509_verify_args, - .sigs = x509_sigs + { + .name = "x509", + .program = "gpgsm", + .verify_args = x509_verify_args, + .sigs = x509_sigs, + .verify_signed_buffer = verify_gpg_signed_buffer, + .sign_buffer = sign_buffer_gpg, }, }; @@ -72,7 +93,7 @@ static struct gpg_format *get_format_by_sig(const char *sig) void signature_check_clear(struct signature_check *sigc) { FREE_AND_NULL(sigc->payload); - FREE_AND_NULL(sigc->gpg_output); + FREE_AND_NULL(sigc->output); FREE_AND_NULL(sigc->gpg_status); FREE_AND_NULL(sigc->signer); FREE_AND_NULL(sigc->key); @@ -257,16 +278,16 @@ error: FREE_AND_NULL(sigc->key); } -static int verify_signed_buffer(const char *payload, size_t payload_size, - const char *signature, size_t signature_size, - struct strbuf *gpg_output, - struct strbuf *gpg_status) +static int verify_gpg_signed_buffer(struct signature_check *sigc, + struct gpg_format *fmt, const char *payload, + size_t payload_size, const char *signature, + size_t signature_size) { struct child_process gpg = CHILD_PROCESS_INIT; - struct gpg_format *fmt; struct tempfile *temp; int ret; - struct strbuf buf = STRBUF_INIT; + struct strbuf gpg_stdout = STRBUF_INIT; + struct strbuf gpg_stderr = STRBUF_INIT; temp = mks_tempfile_t(".git_vtag_tmpXXXXXX"); if (!temp) @@ -279,10 +300,6 @@ static int verify_signed_buffer(const char *payload, size_t payload_size, return -1; } - fmt = get_format_by_sig(signature); - if (!fmt) - BUG("bad signature '%s'", signature); - strvec_push(&gpg.args, fmt->program); strvec_pushv(&gpg.args, fmt->verify_args); strvec_pushl(&gpg.args, @@ -290,18 +307,22 @@ static int verify_signed_buffer(const char *payload, size_t payload_size, "--verify", temp->filename.buf, "-", NULL); - if (!gpg_status) - gpg_status = &buf; - sigchain_push(SIGPIPE, SIG_IGN); - ret = pipe_command(&gpg, payload, payload_size, - gpg_status, 0, gpg_output, 0); + ret = pipe_command(&gpg, payload, payload_size, &gpg_stdout, 0, + &gpg_stderr, 0); sigchain_pop(SIGPIPE); delete_tempfile(&temp); - ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG "); - strbuf_release(&buf); /* no matter it was used or not */ + ret |= !strstr(gpg_stdout.buf, "\n[GNUPG:] GOODSIG "); + sigc->payload = xmemdupz(payload, payload_size); + sigc->output = strbuf_detach(&gpg_stderr, NULL); + sigc->gpg_status = strbuf_detach(&gpg_stdout, NULL); + + parse_gpg_output(sigc); + + strbuf_release(&gpg_stdout); + strbuf_release(&gpg_stderr); return ret; } @@ -309,35 +330,32 @@ static int verify_signed_buffer(const char *payload, size_t payload_size, int check_signature(const char *payload, size_t plen, const char *signature, size_t slen, struct signature_check *sigc) { - struct strbuf gpg_output = STRBUF_INIT; - struct strbuf gpg_status = STRBUF_INIT; + struct gpg_format *fmt; int status; sigc->result = 'N'; sigc->trust_level = -1; - status = verify_signed_buffer(payload, plen, signature, slen, - &gpg_output, &gpg_status); - if (status && !gpg_output.len) - goto out; - sigc->payload = xmemdupz(payload, plen); - sigc->gpg_output = strbuf_detach(&gpg_output, NULL); - sigc->gpg_status = strbuf_detach(&gpg_status, NULL); - parse_gpg_output(sigc); + fmt = get_format_by_sig(signature); + if (!fmt) + return error(_("bad/incompatible signature '%s'"), signature); + + status = fmt->verify_signed_buffer(sigc, fmt, payload, plen, signature, + slen); + + if (status && !sigc->output) + return !!status; + status |= sigc->result != 'G'; status |= sigc->trust_level < configured_min_trust_level; - out: - strbuf_release(&gpg_status); - strbuf_release(&gpg_output); - return !!status; } void print_signature_buffer(const struct signature_check *sigc, unsigned flags) { - const char *output = flags & GPG_VERIFY_RAW ? - sigc->gpg_status : sigc->gpg_output; + const char *output = flags & GPG_VERIFY_RAW ? sigc->gpg_status : + sigc->output; if (flags & GPG_VERIFY_VERBOSE && sigc->payload) fputs(sigc->payload, stdout); @@ -441,6 +459,12 @@ const char *get_signing_key(void) } int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key) +{ + return use_format->sign_buffer(buffer, signature, signing_key); +} + +static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature, + const char *signing_key) { struct child_process gpg = CHILD_PROCESS_INIT; int ret; diff --git a/gpg-interface.h b/gpg-interface.h index 80567e48948..feac4decf8b 100644 --- a/gpg-interface.h +++ b/gpg-interface.h @@ -17,7 +17,7 @@ enum signature_trust_level { struct signature_check { char *payload; - char *gpg_output; + char *output; char *gpg_status; /* diff --git a/log-tree.c b/log-tree.c index 7b823786c2c..20af9bd1c82 100644 --- a/log-tree.c +++ b/log-tree.c @@ -513,10 +513,10 @@ static void show_signature(struct rev_info *opt, struct commit *commit) status = check_signature(payload.buf, payload.len, signature.buf, signature.len, &sigc); - if (status && !sigc.gpg_output) + if (status && !sigc.output) show_sig_lines(opt, status, "No signature\n"); else - show_sig_lines(opt, status, sigc.gpg_output); + show_sig_lines(opt, status, sigc.output); signature_check_clear(&sigc); out: @@ -583,8 +583,8 @@ static int show_one_mergetag(struct commit *commit, /* could have a good signature */ status = check_signature(payload.buf, payload.len, signature.buf, signature.len, &sigc); - if (sigc.gpg_output) - strbuf_addstr(&verify_message, sigc.gpg_output); + if (sigc.output) + strbuf_addstr(&verify_message, sigc.output); else strbuf_addstr(&verify_message, "No signature\n"); signature_check_clear(&sigc); diff --git a/pretty.c b/pretty.c index b1ecd039cef..daa71394efd 100644 --- a/pretty.c +++ b/pretty.c @@ -1432,8 +1432,8 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */ check_commit_signature(c->commit, &(c->signature_check)); switch (placeholder[1]) { case 'G': - if (c->signature_check.gpg_output) - strbuf_addstr(sb, c->signature_check.gpg_output); + if (c->signature_check.output) + strbuf_addstr(sb, c->signature_check.output); break; case '?': switch (c->signature_check.result) { -- gitgitgadget