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[PATCH v3 1/2] http: add client cert for HTTPS proxies.

From
JGJorge Lopez Silva via GitGitGadget <gitgitgadget@gmail.com>
Date
Mar 4, 2020, 18:40 UTC
Message-ID
<e18b342819b445281732269def1912a044171bab.1583347206.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.559.v3.git.1583347206.gitgitgadget@gmail.com>
From: Jorge Lopez Silva <jalopezsilva@gmail.com>

Git currently supports performing connections to HTTPS proxies but we don't support doing mutual authentication with them (through TLS). This commit adds the necessary options to be able to send a client certificate to the HTTPS proxy.

A client certificate can provide an alternative way of authentication instead of using 'ProxyAuthorization' or other more common methods of authentication. Libcurl supports this functionality already so changes are somewhat minimal. The feature is guarded by the first available libcurl version that supports these options.

4 configuration options are added and documented, cert, key, cert password protected and CA info. The CA info should be used to specify a different CA path to validate the HTTPS proxy cert.

Signed-off-by: Jorge Lopez Silva <jalopezsilva@gmail.com>
---
 Documentation/config/http.txt | 17 +++++++++
 http.c                        | 67 ++++++++++++++++++++++++++++++++---
 2 files changed, 79 insertions(+), 5 deletions(-)
diff --git a/Documentation/config/http.txt b/Documentation/config/http.txt
index e806033aab8..7d398f9afba 100644
--- a/Documentation/config/http.txt
+++ b/Documentation/config/http.txt
@@ -29,6 +29,23 @@ http.proxyAuthMethod::
 * `ntlm` - NTLM authentication (compare the --ntlm option of `curl(1)`)
 --
 
+http.proxySSLCert::
+	The pathname of a file that stores a client certificate to use to authenticate
+	with an HTTPS proxy.
+
+http.proxySSLKey::
+	The pathname of a file that stores a private key to use to authenticate with
+	an HTTPS proxy.
+
+http.proxySSLCertPasswordProtected::
+	Enable Git's password prompt for the proxy SSL certificate.  Otherwise OpenSSL
+	will prompt the user, possibly many times, if the certificate or private key
+	is encrypted.
+
+http.proxySSLCAInfo::
+	Pathname to the file containing the certificate bundle that should be used to
+	verify the proxy with when using an HTTPS proxy.
+
 http.emptyAuth::
 	Attempt authentication without seeking a username or password.  This
 	can be used to attempt GSS-Negotiate authentication without specifying
diff --git a/http.c b/http.c
index 00a0e507633..8d616b5d60e 100644
--- a/http.c
+++ b/http.c
@@ -86,6 +86,13 @@ static long curl_low_speed_time = -1;
 static int curl_ftp_no_epsv;
 static const char *curl_http_proxy;
 static const char *http_proxy_authmethod;
+
+static const char *http_proxy_ssl_cert;
+static const char *http_proxy_ssl_key;
+static const char *http_proxy_ssl_ca_info;
+static struct credential proxy_cert_auth = CREDENTIAL_INIT;
+static int proxy_ssl_cert_password_required;
+
 static struct {
 	const char *name;
 	long curlauth_param;
@@ -365,6 +372,20 @@ static int http_options(const char *var, const char *value, void *cb)
 	if (!strcmp("http.proxyauthmethod", var))
 		return git_config_string(&http_proxy_authmethod, var, value);
 
+	if (!strcmp("http.proxysslcert", var))
+		return git_config_string(&http_proxy_ssl_cert, var, value);
+
+	if (!strcmp("http.proxysslkey", var))
+		return git_config_string(&http_proxy_ssl_key, var, value);
+
+	if (!strcmp("http.proxysslcainfo", var))
+		return git_config_string(&http_proxy_ssl_ca_info, var, value);
+
+	if (!strcmp("http.proxysslcertpasswordprotected", var)) {
+		proxy_ssl_cert_password_required = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp("http.cookiefile", var))
 		return git_config_pathname(&curl_cookie_file, var, value);
 	if (!strcmp("http.savecookies", var)) {
@@ -565,6 +586,21 @@ static int has_cert_password(void)
 	return 1;
 }
 
+#if LIBCURL_VERSION_NUM >= 0x073400
+static int has_proxy_cert_password(void)
+{
+	if (http_proxy_ssl_cert == NULL || proxy_ssl_cert_password_required != 1)
+		return 0;
+	if (!proxy_cert_auth.password) {
+		proxy_cert_auth.protocol = xstrdup("cert");
+		proxy_cert_auth.username = xstrdup("");
+		proxy_cert_auth.path = xstrdup(http_proxy_ssl_cert);
+		credential_fill(&proxy_cert_auth);
+	}
+	return 1;
+}
+#endif
+
 #if LIBCURL_VERSION_NUM >= 0x071900
 static void set_curl_keepalive(CURL *c)
 {
@@ -924,8 +960,14 @@ static CURL *get_curl_handle(void)
 #if LIBCURL_VERSION_NUM >= 0x073400
 		curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, NULL);
 #endif
-	} else if (ssl_cainfo != NULL)
-		curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
+	} else if (ssl_cainfo != NULL || http_proxy_ssl_ca_info != NULL) {
+		if (ssl_cainfo != NULL)
+			curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
+#if LIBCURL_VERSION_NUM >= 0x073400
+		if (http_proxy_ssl_ca_info != NULL)
+			curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, http_proxy_ssl_ca_info);
+#endif
+	}
 
 	if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 		curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
@@ -1018,9 +1060,18 @@ static CURL *get_curl_handle(void)
 				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
 #endif
 #if LIBCURL_VERSION_NUM >= 0x073400
-		else if (starts_with(curl_http_proxy, "https"))
-			curl_easy_setopt(result,
-				CURLOPT_PROXYTYPE, CURLPROXY_HTTPS);
+		else if (starts_with(curl_http_proxy, "https")) {
+			curl_easy_setopt(result, CURLOPT_PROXYTYPE, CURLPROXY_HTTPS);
+
+			if (http_proxy_ssl_cert)
+				curl_easy_setopt(result, CURLOPT_PROXY_SSLCERT, http_proxy_ssl_cert);
+
+			if (http_proxy_ssl_key)
+				curl_easy_setopt(result, CURLOPT_PROXY_SSLKEY, http_proxy_ssl_key);
+
+			if (has_proxy_cert_password())
+				curl_easy_setopt(result, CURLOPT_PROXY_KEYPASSWD, proxy_cert_auth.password);
+		}
 #endif
 		if (strstr(curl_http_proxy, "://"))
 			credential_from_url(&proxy_auth, curl_http_proxy);
@@ -1230,6 +1281,12 @@ void http_cleanup(void)
 	}
 	ssl_cert_password_required = 0;
 
+	if (proxy_cert_auth.password != NULL) {
+		memset(proxy_cert_auth.password, 0, strlen(proxy_cert_auth.password));
+		FREE_AND_NULL(proxy_cert_auth.password);
+	}
+	proxy_ssl_cert_password_required = 0;
+
 	FREE_AND_NULL(cached_accept_language);
 }
 
-- 
gitgitgadget
Previous: Jorge via GitGitGadgetNext: Jorge Lopez Silva via GitGitGadget
Message 14 of 15 in “Add HTTPS proxy SSL options (cert, key, cainfo)”
  1. 0/2 Add HTTPS proxy SSL options (cert, key, cainfo)Jorge via GitGitGadget, Feb 21, 2020
  2. 1/2 http: add client cert for HTTPS proxies.Jorge Lopez Silva via GitGitGadget, Feb 21, 2020
  3. Eric SunshineFeb 21, 2020
  4. Jorge A López SilvaFeb 26, 2020
  5. 2/2 config: documentation for HTTPS proxy client cert.Jorge Lopez Silva via GitGitGadget, Feb 21, 2020
  6. 0/2 Add HTTPS proxy SSL options (cert, key, cainfo)Jorge via GitGitGadget, Feb 26, 2020
  7. 2/2 config: documentation for HTTPS proxy client cert.Jorge Lopez Silva via GitGitGadget, Feb 26, 2020
  8. Junio C HamanoFeb 27, 2020
  9. Jorge A López SilvaMar 3, 2020
  10. 1/2 http: add client cert for HTTPS proxies.Jorge Lopez Silva via GitGitGadget, Feb 26, 2020
  11. Junio C HamanoFeb 27, 2020
  12. Jorge A López SilvaMar 3, 2020
  13. 0/2 Add HTTPS proxy SSL options (cert, key, cainfo)Jorge via GitGitGadget, Mar 4, 2020
  14. 1/2 http: add client cert for HTTPS proxies.Jorge Lopez Silva via GitGitGadget, Mar 4, 2020
  15. 2/2 http: add environment variable for HTTPS proxy.Jorge Lopez Silva via GitGitGadget, Mar 4, 2020

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