Merge branch 'js/mingw-http-ssl'

On platforms with recent cURL library, http.sslBackend configuration
variable can be used to choose a different SSL backend at runtime.
The Windows port uses this mechanism to switch between OpenSSL and
Secure Channel while talking over the HTTPS protocol.

* js/mingw-http-ssl:
http: when using Secure Channel, ignore sslCAInfo by default
http: add support for disabling SSL revocation checks in cURL
http: add support for selecting SSL backends at runtime

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 09e95e9e98bc0c28e2141c96fab8addbe68f11d8..41a9ff2b6aa4ebcc87179ede7a70f680e2eba439 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2003,6 +2003,27 @@ http.sslCAPath::
        with when fetching or pushing over HTTPS. Can be overridden
        by the `GIT_SSL_CAPATH` environment variable.
 
+http.sslBackend::
+       Name of the SSL backend to use (e.g. "openssl" or "schannel").
+       This option is ignored if cURL lacks support for choosing the SSL
+       backend at runtime.
+
+http.schannelCheckRevoke::
+       Used to enforce or disable certificate revocation checks in cURL
+       when http.sslBackend is set to "schannel". Defaults to `true` if
+       unset. Only necessary to disable this if Git consistently errors
+       and the message is about checking the revocation status of a
+       certificate. This option is ignored if cURL lacks support for
+       setting the relevant SSL option at runtime.
+
+http.schannelUseSSLCAInfo::
+       As of cURL v7.60.0, the Secure Channel backend can use the
+       certificate bundle provided via `http.sslCAInfo`, but that would
+       override the Windows Certificate Store. Since this is not desirable
+       by default, Git will tell cURL not to use that bundle by default
+       when the `schannel` backend was configured via `http.sslBackend`,
+       unless `http.schannelUseSSLCAInfo` overrides this behavior.
+
 http.pinnedpubkey::
        Public key of the https service. It may either be the filename of
        a PEM or DER encoded public key file or a string starting with

diff --git a/http.c b/http.c
index 98ff122585c4da84894ccae97db54859e45f3bec..28009ca73ac859160ea8aa34ac8b3ace8692e1e2 100644 (file)
--- a/http.c
+++ b/http.c
@@ -155,6 +155,16 @@ static struct active_request_slot *active_queue_head;
 
 static char *cached_accept_language;
 
+static char *http_ssl_backend;
+
+static int http_schannel_check_revoke = 1;
+/*
+ * With the backend being set to `schannel`, setting sslCAinfo would override
+ * the Certificate Store in cURL v7.60.0 and later, which is not what we want
+ * by default.
+ */
+static int http_schannel_use_ssl_cainfo;
+
 size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
        size_t size = eltsize * nmemb;
@@ -302,6 +312,22 @@ static int http_options(const char *var, const char *value, void *cb)
                curl_ssl_try = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp("http.sslbackend", var)) {
+               free(http_ssl_backend);
+               http_ssl_backend = xstrdup_or_null(value);
+               return 0;
+       }
+
+       if (!strcmp("http.schannelcheckrevoke", var)) {
+               http_schannel_check_revoke = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (!strcmp("http.schannelusesslcainfo", var)) {
+               http_schannel_use_ssl_cainfo = git_config_bool(var, value);
+               return 0;
+       }
+
        if (!strcmp("http.minsessions", var)) {
                min_curl_sessions = git_config_int(var, value);
 #ifndef USE_CURL_MULTI
@@ -803,6 +829,16 @@ static CURL *get_curl_handle(void)
        }
 #endif
 
+       if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
+           !http_schannel_check_revoke) {
+#if LIBCURL_VERSION_NUM >= 0x072c00
+               curl_easy_setopt(result, CURLOPT_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
+#else
+               warning("CURLSSLOPT_NO_REVOKE not applied to curl SSL options because\n"
+                       "your curl version is too old (< 7.44.0)");
+#endif
+       }
+
        if (http_proactive_auth)
                init_curl_http_auth(result);
 
@@ -844,7 +880,13 @@ static CURL *get_curl_handle(void)
        if (ssl_pinnedkey != NULL)
                curl_easy_setopt(result, CURLOPT_PINNEDPUBLICKEY, ssl_pinnedkey);
 #endif
-       if (ssl_cainfo != NULL)
+       if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
+           !http_schannel_use_ssl_cainfo) {
+               curl_easy_setopt(result, CURLOPT_CAINFO, NULL);
+#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);
 
        if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
@@ -995,6 +1037,33 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
        git_config(urlmatch_config_entry, &config);
        free(normalized_url);
 
+#if LIBCURL_VERSION_NUM >= 0x073800
+       if (http_ssl_backend) {
+               const curl_ssl_backend **backends;
+               struct strbuf buf = STRBUF_INIT;
+               int i;
+
+               switch (curl_global_sslset(-1, http_ssl_backend, &backends)) {
+               case CURLSSLSET_UNKNOWN_BACKEND:
+                       strbuf_addf(&buf, _("Unsupported SSL backend '%s'. "
+                                           "Supported SSL backends:"),
+                                           http_ssl_backend);
+                       for (i = 0; backends[i]; i++)
+                               strbuf_addf(&buf, "\n\t%s", backends[i]->name);
+                       die("%s", buf.buf);
+               case CURLSSLSET_NO_BACKENDS:
+                       die(_("Could not set SSL backend to '%s': "
+                             "cURL was built without SSL backends"),
+                           http_ssl_backend);
+               case CURLSSLSET_TOO_LATE:
+                       die(_("Could not set SSL backend to '%s': already set"),
+                           http_ssl_backend);
+               case CURLSSLSET_OK:
+                       break; /* Okay! */
+               }
+       }
+#endif
+
        if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
                die("curl_global_init failed");