From patchwork Thu Jan 7 06:36:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick Steinhardt X-Patchwork-Id: 12003045 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5236BC4332B for ; Thu, 7 Jan 2021 06:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17DD1230FC for ; Thu, 7 Jan 2021 06:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726608AbhAGGiE (ORCPT ); Thu, 7 Jan 2021 01:38:04 -0500 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:49707 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725763AbhAGGiE (ORCPT ); Thu, 7 Jan 2021 01:38:04 -0500 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 191735C00C3; Thu, 7 Jan 2021 01:36:57 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Thu, 07 Jan 2021 01:36:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pks.im; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm3; bh=k1ZdIyCHQOscgcPn2wPJB2WHGIn JiIE+ah/VWynsW9c=; b=EqNV5Bt2D5IRTRbeIfcjtp7VwKeuFSkgPo1htvJpWtt +19WwhWUxTIIAUXIck+sOW03/JS4+EK/oNZCHe3PlUVuvz13q8QBFAjSjStIjJei HhepWXE8pUSlbvOaSje8PvweQFXOlGWQYaFGdZdTwYAs9md5WvGGfdsIqEj7bv5B MvwhmvYv08/Fecbb6pQzpUuB1bK48uyq4zDxSCGNrMd+u5BEeC+AZWzpfvi81YLB jBD9F7OuNQ4ahLaDMtchhCGdvbdZhTIruJDyMDTDPklcaqvfjxEiHqCsrNuapP0K 8KOSyPegIsbkFoEdwp5XCwquXq3aA4g4BeYlXyij43A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=k1ZdIy CHQOscgcPn2wPJB2WHGInJiIE+ah/VWynsW9c=; b=SkGS21ttIsLuTT/39vUnCB XFCLMP8i31kfxPIV/Lf9457065XiN8pK8Ae5N5z1RyNCPBZD4B1UL2Y8aOLbFjuO T80Zna53LRNIR7ZYUiolesDCfBZj3k6sPnhZWRNAsuh6ZydNAwvOMHldu8l96vDG cCBUUyPVGk1pOI5DFba8Wy9gm/PAaMGa1wXOcOJcEhYER6AKdb/mYCUb7g5n1lJR dcTN9dNbNf5JqAspSH28HSXqR6WUifAeQazbUNtcigpzs1oUzxe5NMQfcpO98u/Y CmY3m0Y766HY08mdvHs4DRHt2jIrep/rWW44VQvgehu0ImMes6/JFj1p3055MGSg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrvdeguddgudejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehgtderredttddvnecuhfhrohhmpefrrghtrhhi tghkucfuthgvihhnhhgrrhguthcuoehpshesphhkshdrihhmqeenucggtffrrghtthgvrh hnpeehgefhtdefueffheekgfffudelffejtdfhvdejkedthfehvdelgfetgfdvtedthfen ucfkphepjeejrddufedrfeegrddvfedvnecuvehluhhsthgvrhfuihiivgepvdenucfrrg hrrghmpehmrghilhhfrhhomhepphhssehpkhhsrdhimh X-ME-Proxy: Received: from vm-mail.pks.im (dynamic-077-013-034-232.77.13.pool.telefonica.de [77.13.34.232]) by mail.messagingengine.com (Postfix) with ESMTPA id 0DC7A24005B; Thu, 7 Jan 2021 01:36:55 -0500 (EST) Received: from localhost (ncase [10.192.0.11]) by vm-mail.pks.im (OpenSMTPD) with ESMTPSA id 380129f3 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 7 Jan 2021 06:36:53 +0000 (UTC) Date: Thu, 7 Jan 2021 07:36:52 +0100 From: Patrick Steinhardt To: git@vger.kernel.org Cc: =?iso-8859-1?q?=C6var_Arnfj=F6r=F0?= Bjarmason , Junio C Hamano , Jeff King , "brian m. carlson" , Philip Oakley Subject: [PATCH v6 2/8] config: add new way to pass config via `--config-env` Message-ID: <9b8461010e641369316d00e2fc58c16e0e191f42.1610001187.git.ps@pks.im> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org While it's already possible to pass runtime configuration via `git -c =`, it may be undesirable to use when the value contains sensitive information. E.g. if one wants to set `http.extraHeader` to contain an authentication token, doing so via `-c` would trivially leak those credentials via e.g. ps(1), which typically also shows command arguments. To enable this usecase without leaking credentials, this commit introduces a new switch `--config-env==`. Instead of directly passing a value for the given key, it instead allows the user to specify the name of an environment variable. The value of that variable will then be used as value of the key. Co-authored-by: Jeff King Signed-off-by: Patrick Steinhardt --- Documentation/git.txt | 24 ++++++++++++++++++++++- config.c | 21 ++++++++++++++++++++ config.h | 1 + git.c | 4 +++- t/t1300-config.sh | 45 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 93 insertions(+), 2 deletions(-) diff --git a/Documentation/git.txt b/Documentation/git.txt index a6d4ad0818..d36e6fd482 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -13,7 +13,7 @@ SYNOPSIS [--exec-path[=]] [--html-path] [--man-path] [--info-path] [-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare] [--git-dir=] [--work-tree=] [--namespace=] - [--super-prefix=] + [--super-prefix=] [--config-env =] [] DESCRIPTION @@ -80,6 +80,28 @@ config file). Including the equals but with an empty value (like `git -c foo.bar= ...`) sets `foo.bar` to the empty string which `git config --type=bool` will convert to `false`. +--config-env==:: + Like `-c =`, give configuration variable + '' a value, where is the name of an + environment variable from which to retrieve the value. Unlike + `-c` there is no shortcut for directly setting the value to an + empty string, instead the environment variable itself must be + set to the empty string. It is an error if the `` does not exist + in the environment. `` may not contain an equals sign + to avoid ambiguity with ``s which contain one. ++ +This is useful for cases where you want to pass transitory +configuration options to git, but are doing so on OS's where +other processes might be able to read your cmdline +(e.g. `/proc/self/cmdline`), but not your environ +(e.g. `/proc/self/environ`). That behavior is the default on +Linux, but may not be on your system. ++ +Note that this might add security for variables such as +`http.extraHeader` where the sensitive information is part of +the value, but not e.g. `url..insteadOf` where the +sensitive information can be part of the key. + --exec-path[=]:: Path to wherever your core Git programs are installed. This can also be controlled by setting the GIT_EXEC_PATH diff --git a/config.c b/config.c index 1137bd73af..cde3511110 100644 --- a/config.c +++ b/config.c @@ -345,6 +345,27 @@ void git_config_push_parameter(const char *text) strbuf_release(&env); } +void git_config_push_env(const char *spec) +{ + struct strbuf buf = STRBUF_INIT; + const char *env_name; + const char *env_value; + + env_name = strrchr(spec, '='); + if (!env_name) + die("invalid config format: %s", spec); + env_name++; + + env_value = getenv(env_name); + if (!env_value) + die("config variable missing for '%s'", env_name); + + strbuf_add(&buf, spec, env_name - spec); + strbuf_addstr(&buf, env_value); + git_config_push_parameter(buf.buf); + strbuf_release(&buf); +} + static inline int iskeychar(int c) { return isalnum(c) || c == '-'; diff --git a/config.h b/config.h index c1449bb790..19a9adbaa9 100644 --- a/config.h +++ b/config.h @@ -138,6 +138,7 @@ int git_config_from_mem(config_fn_t fn, int git_config_from_blob_oid(config_fn_t fn, const char *name, const struct object_id *oid, void *data); void git_config_push_parameter(const char *text); +void git_config_push_env(const char *spec); int git_config_from_parameters(config_fn_t fn, void *data); void read_early_config(config_fn_t cb, void *data); void read_very_early_config(config_fn_t cb, void *data); diff --git a/git.c b/git.c index 5a8ff12f87..b5f63d346b 100644 --- a/git.c +++ b/git.c @@ -29,7 +29,7 @@ const char git_usage_string[] = " [--exec-path[=]] [--html-path] [--man-path] [--info-path]\n" " [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n" " [--git-dir=] [--work-tree=] [--namespace=]\n" - " [--super-prefix=]\n" + " [--super-prefix=] [--config-env==]\n" " []"); const char git_more_info_string[] = @@ -255,6 +255,8 @@ static int handle_options(const char ***argv, int *argc, int *envchanged) git_config_push_parameter((*argv)[1]); (*argv)++; (*argc)--; + } else if (skip_prefix(cmd, "--config-env=", &cmd)) { + git_config_push_env(cmd); } else if (!strcmp(cmd, "--literal-pathspecs")) { setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1); if (envchanged) diff --git a/t/t1300-config.sh b/t/t1300-config.sh index 97a04c6cc2..46a94814d5 100755 --- a/t/t1300-config.sh +++ b/t/t1300-config.sh @@ -1316,6 +1316,51 @@ test_expect_success 'detect bogus GIT_CONFIG_PARAMETERS' ' git config --get-regexp "env.*" ' +test_expect_success 'git --config-env=key=envvar support' ' + cat >expect <<-\EOF && + value + value + false + EOF + { + env ENVVAR=value git --config-env=core.name=ENVVAR config core.name && + env ENVVAR=value git --config-env=foo.CamelCase=ENVVAR config foo.camelcase && + env ENVVAR= git --config-env=foo.flag=ENVVAR config --bool foo.flag + } >actual && + test_cmp expect actual +' + +test_expect_success 'git --config-env fails with invalid parameters' ' + test_must_fail git --config-env=foo.flag config --bool foo.flag 2>error && + test_i18ngrep "invalid config format" error && + test_must_fail git --config-env=foo.flag=NONEXISTENT config --bool foo.flag 2>error && + test_i18ngrep "config variable missing" error +' + +test_expect_success 'git -c and --config-env work together' ' + cat >expect <<-\EOF && + bar.cmd cmd-value + bar.env env-value + EOF + env ENVVAR=env-value git \ + -c bar.cmd=cmd-value \ + --config-env=bar.env=ENVVAR \ + config --get-regexp "^bar.*" >actual && + test_cmp expect actual +' + +test_expect_success 'git -c and --config-env override each other' ' + cat >expect <<-\EOF && + env + cmd + EOF + { + env ENVVAR=env git -c bar.bar=cmd --config-env=bar.bar=ENVVAR config bar.bar && + env ENVVAR=env git --config-env=bar.bar=ENVVAR -c bar.bar=cmd config bar.bar + } >actual && + test_cmp expect actual +' + test_expect_success 'git config --edit works' ' git config -f tmp test.value no && echo test.value=yes >expect &&