1 files changed, 189 insertions, 52 deletions

diff --git a/http.c b/http.c
index cd40b012f8..d2e11ec6f0 100644
--- a/http.c
+++ b/http.c
@@ -19,7 +19,7 @@ long int git_curl_ipresolve;
 #endif
 int active_requests;
 int http_is_verbose;
-size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
+ssize_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
 #if LIBCURL_VERSION_NUM >= 0x070a06
 #define LIBCURL_CAN_HANDLE_AUTH_ANY
@@ -90,6 +90,18 @@ static struct {
 	 * here, too
 	 */
 };
+#if LIBCURL_VERSION_NUM >= 0x071600
+static const char *curl_deleg;
+static struct {
+	const char *name;
+	long curl_deleg_param;
+} curl_deleg_levels[] = {
+	{ "none", CURLGSSAPI_DELEGATION_NONE },
+	{ "policy", CURLGSSAPI_DELEGATION_POLICY_FLAG },
+	{ "always", CURLGSSAPI_DELEGATION_FLAG },
+};
+#endif
+
 static struct credential proxy_auth = CREDENTIAL_INIT;
 static const char *curl_proxyuserpwd;
 static const char *curl_cookie_file;
@@ -97,7 +109,9 @@ static int curl_save_cookies;
 struct credential http_auth = CREDENTIAL_INIT;
 static int http_proactive_auth;
 static const char *user_agent;
-static int curl_empty_auth;
+static int curl_empty_auth = -1;
+
+enum http_follow_config http_follow_config = HTTP_FOLLOW_INITIAL;
 
 #if LIBCURL_VERSION_NUM >= 0x071700
 /* Use CURLOPT_KEYPASSWD as is */
@@ -111,6 +125,14 @@ static struct credential cert_auth = CREDENTIAL_INIT;
 static int ssl_cert_password_required;
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 static unsigned long http_auth_methods = CURLAUTH_ANY;
+static int http_auth_methods_restricted;
+/* Modes for which empty_auth cannot actually help us. */
+static unsigned long empty_auth_useless =
+	CURLAUTH_BASIC
+#ifdef CURLAUTH_DIGEST_IE
+	| CURLAUTH_DIGEST_IE
+#endif
+	| CURLAUTH_DIGEST;
 #endif
 
 static struct curl_slist *pragma_header;
@@ -201,6 +223,13 @@ static void finish_active_slot(struct active_request_slot *slot)
 		slot->callback_func(slot->callback_data);
 }
 
+static void xmulti_remove_handle(struct active_request_slot *slot)
+{
+#ifdef USE_CURL_MULTI
+	curl_multi_remove_handle(curlm, slot->curl);
+#endif
+}
+
 #ifdef USE_CURL_MULTI
 static void process_curl_messages(void)
 {
@@ -216,7 +245,7 @@ static void process_curl_messages(void)
 			       slot->curl != curl_message->easy_handle)
 				slot = slot->next;
 			if (slot != NULL) {
-				curl_multi_remove_handle(curlm, slot->curl);
+				xmulti_remove_handle(slot);
 				slot->curl_result = curl_result;
 				finish_active_slot(slot);
 			} else {
@@ -302,7 +331,9 @@ static int http_options(const char *var, const char *value, void *cb)
 	}
 
 	if (!strcmp("http.postbuffer", var)) {
-		http_post_buffer = git_config_int(var, value);
+		http_post_buffer = git_config_ssize_t(var, value);
+		if (http_post_buffer < 0)
+			warning(_("negative value for http.postbuffer; defaulting to %d"), LARGE_PACKET_MAX);
 		if (http_post_buffer < LARGE_PACKET_MAX)
 			http_post_buffer = LARGE_PACKET_MAX;
 		return 0;
@@ -312,8 +343,20 @@ static int http_options(const char *var, const char *value, void *cb)
 		return git_config_string(&user_agent, var, value);
 
 	if (!strcmp("http.emptyauth", var)) {
-		curl_empty_auth = git_config_bool(var, value);
+		if (value && !strcmp("auto", value))
+			curl_empty_auth = -1;
+		else
+			curl_empty_auth = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.delegation", var)) {
+#if LIBCURL_VERSION_NUM >= 0x071600
+		return git_config_string(&curl_deleg, var, value);
+#else
+		warning(_("Delegation control is not supported with cURL < 7.22.0"));
 		return 0;
+#endif
 	}
 
 	if (!strcmp("http.pinnedpubkey", var)) {
@@ -338,14 +381,51 @@ static int http_options(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (!strcmp("http.followredirects", var)) {
+		if (value && !strcmp(value, "initial"))
+			http_follow_config = HTTP_FOLLOW_INITIAL;
+		else if (git_config_bool(var, value))
+			http_follow_config = HTTP_FOLLOW_ALWAYS;
+		else
+			http_follow_config = HTTP_FOLLOW_NONE;
+		return 0;
+	}
+
 	/* Fall back on the default ones */
 	return git_default_config(var, value, cb);
 }
 
+static int curl_empty_auth_enabled(void)
+{
+	if (curl_empty_auth >= 0)
+		return curl_empty_auth;
+
+#ifndef LIBCURL_CAN_HANDLE_AUTH_ANY
+	/*
+	 * Our libcurl is too old to do AUTH_ANY in the first place;
+	 * just default to turning the feature off.
+	 */
+#else
+	/*
+	 * In the automatic case, kick in the empty-auth
+	 * hack as long as we would potentially try some
+	 * method more exotic than "Basic" or "Digest".
+	 *
+	 * But only do this when this is our second or
+	 * subsequent request, as by then we know what
+	 * methods are available.
+	 */
+	if (http_auth_methods_restricted &&
+	    (http_auth_methods & ~empty_auth_useless))
+		return 1;
+#endif
+	return 0;
+}
+
 static void init_curl_http_auth(CURL *result)
 {
-	if (!http_auth.username) {
-		if (curl_empty_auth)
+	if (!http_auth.username || !*http_auth.username) {
+		if (curl_empty_auth_enabled())
 			curl_easy_setopt(result, CURLOPT_USERPWD, ":");
 		return;
 	}
@@ -596,11 +676,25 @@ void setup_curl_trace(CURL *handle)
 	curl_easy_setopt(handle, CURLOPT_DEBUGDATA, NULL);
 }
 
+static long get_curl_allowed_protocols(int from_user)
+{
+	long allowed_protocols = 0;
+
+	if (is_transport_allowed("http", from_user))
+		allowed_protocols |= CURLPROTO_HTTP;
+	if (is_transport_allowed("https", from_user))
+		allowed_protocols |= CURLPROTO_HTTPS;
+	if (is_transport_allowed("ftp", from_user))
+		allowed_protocols |= CURLPROTO_FTP;
+	if (is_transport_allowed("ftps", from_user))
+		allowed_protocols |= CURLPROTO_FTPS;
+
+	return allowed_protocols;
+}
 
 static CURL *get_curl_handle(void)
 {
 	CURL *result = curl_easy_init();
-	long allowed_protocols = 0;
 
 	if (!result)
 		die("curl_easy_init failed");
@@ -622,6 +716,22 @@ static CURL *get_curl_handle(void)
 	curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 #endif
 
+#if LIBCURL_VERSION_NUM >= 0x071600
+	if (curl_deleg) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(curl_deleg_levels); i++) {
+			if (!strcmp(curl_deleg, curl_deleg_levels[i].name)) {
+				curl_easy_setopt(result, CURLOPT_GSSAPI_DELEGATION,
+						curl_deleg_levels[i].curl_deleg_param);
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(curl_deleg_levels))
+			warning("Unknown delegation method '%s': using default",
+				curl_deleg);
+	}
+#endif
+
 	if (http_proactive_auth)
 		init_curl_http_auth(result);
 
@@ -673,7 +783,6 @@ static CURL *get_curl_handle(void)
 				 curl_low_speed_time);
 	}
 
-	curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
 	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
 #if LIBCURL_VERSION_NUM >= 0x071301
 	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
@@ -681,19 +790,13 @@ static CURL *get_curl_handle(void)
 	curl_easy_setopt(result, CURLOPT_POST301, 1);
 #endif
 #if LIBCURL_VERSION_NUM >= 0x071304
-	if (is_transport_allowed("http"))
-		allowed_protocols |= CURLPROTO_HTTP;
-	if (is_transport_allowed("https"))
-		allowed_protocols |= CURLPROTO_HTTPS;
-	if (is_transport_allowed("ftp"))
-		allowed_protocols |= CURLPROTO_FTP;
-	if (is_transport_allowed("ftps"))
-		allowed_protocols |= CURLPROTO_FTPS;
-	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS, allowed_protocols);
+	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
+			 get_curl_allowed_protocols(0));
+	curl_easy_setopt(result, CURLOPT_PROTOCOLS,
+			 get_curl_allowed_protocols(-1));
 #else
-	if (transport_restrict_protocols())
-		warning("protocol restrictions not applied to curl redirects because\n"
-			"your curl version is too old (>= 7.19.4)");
+	warning("protocol restrictions not applied to curl redirects because\n"
+		"your curl version is too old (>= 7.19.4)");
 #endif
 	if (getenv("GIT_CURL_VERBOSE"))
 		curl_easy_setopt(result, CURLOPT_VERBOSE, 1L);
@@ -723,7 +826,7 @@ static CURL *get_curl_handle(void)
 	 * precedence here, as in CURL.
 	 */
 	if (!curl_http_proxy) {
-		if (!strcmp(http_auth.protocol, "https")) {
+		if (http_auth.protocol && !strcmp(http_auth.protocol, "https")) {
 			var_override(&curl_http_proxy, getenv("HTTPS_PROXY"));
 			var_override(&curl_http_proxy, getenv("https_proxy"));
 		} else {
@@ -735,8 +838,14 @@ static CURL *get_curl_handle(void)
 		}
 	}
 
-	if (curl_http_proxy) {
-		curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+	if (curl_http_proxy && curl_http_proxy[0] == '\0') {
+		/*
+		 * Handle case with the empty http.proxy value here to keep
+		 * common code clean.
+		 * NB: empty option disables proxying at all.
+		 */
+		curl_easy_setopt(result, CURLOPT_PROXY, "");
+	} else if (curl_http_proxy) {
 #if LIBCURL_VERSION_NUM >= 0x071800
 		if (starts_with(curl_http_proxy, "socks5h"))
 			curl_easy_setopt(result,
@@ -760,6 +869,9 @@ static CURL *get_curl_handle(void)
 			strbuf_release(&url);
 		}
 
+		if (!proxy_auth.host)
+			die("Invalid proxy URL '%s'", curl_http_proxy);
+
 		curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
 #if LIBCURL_VERSION_NUM >= 0x071304
 		var_override(&curl_no_proxy, getenv("NO_PROXY"));
@@ -881,9 +993,7 @@ void http_cleanup(void)
 	while (slot != NULL) {
 		struct active_request_slot *next = slot->next;
 		if (slot->curl != NULL) {
-#ifdef USE_CURL_MULTI
-			curl_multi_remove_handle(curlm, slot->curl);
-#endif
+			xmulti_remove_handle(slot);
 			curl_easy_cleanup(slot->curl);
 		}
 		free(slot);
@@ -1002,13 +1112,23 @@ struct active_request_slot *get_active_slot(void)
 	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_RANGE, NULL);
 
+	/*
+	 * Default following to off unless "ALWAYS" is configured; this gives
+	 * callers a sane starting point, and they can tweak for individual
+	 * HTTP_FOLLOW_* cases themselves.
+	 */
+	if (http_follow_config == HTTP_FOLLOW_ALWAYS)
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+	else
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 0);
+
 #if LIBCURL_VERSION_NUM >= 0x070a08
 	curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
 #endif
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
 #endif
-	if (http_auth.password || curl_empty_auth)
+	if (http_auth.password || curl_empty_auth_enabled())
 		init_curl_http_auth(slot->curl);
 
 	return slot;
@@ -1022,6 +1142,8 @@ int start_active_slot(struct active_request_slot *slot)
 
 	if (curlm_result != CURLM_OK &&
 	    curlm_result != CURLM_CALL_MULTI_PERFORM) {
+		warning("curl_multi_add_handle failed: %s",
+			curl_multi_strerror(curlm_result));
 		active_requests--;
 		slot->in_use = 0;
 		return 0;
@@ -1161,13 +1283,13 @@ void run_active_slot(struct active_request_slot *slot)
 static void release_active_slot(struct active_request_slot *slot)
 {
 	closedown_active_slot(slot);
-	if (slot->curl && curl_session_count > min_curl_sessions) {
-#ifdef USE_CURL_MULTI
-		curl_multi_remove_handle(curlm, slot->curl);
-#endif
-		curl_easy_cleanup(slot->curl);
-		slot->curl = NULL;
-		curl_session_count--;
+	if (slot->curl) {
+		xmulti_remove_handle(slot);
+		if (curl_session_count > min_curl_sessions) {
+			curl_easy_cleanup(slot->curl);
+			slot->curl = NULL;
+			curl_session_count--;
+		}
 	}
 #ifdef USE_CURL_MULTI
 	fill_active_slots();
@@ -1242,9 +1364,12 @@ static int handle_curl_result(struct slot_results *results)
 	 * If we see a failing http code with CURLE_OK, we have turned off
 	 * FAILONERROR (to keep the server's custom error response), and should
 	 * translate the code into failure here.
+	 *
+	 * Likewise, if we see a redirect (30x code), that means we turned off
+	 * redirect-following, and we should treat the result as an error.
 	 */
 	if (results->curl_result == CURLE_OK &&
-	    results->http_code >= 400) {
+	    results->http_code >= 300) {
 		results->curl_result = CURLE_HTTP_RETURNED_ERROR;
 		/*
 		 * Normally curl will already have put the "reason phrase"
@@ -1252,9 +1377,9 @@ static int handle_curl_result(struct slot_results *results)
 		 * FAILONERROR it is lost, so we can give only the numeric
 		 * status code.
 		 */
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "The requested URL returned error: %ld",
-			 results->http_code);
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "The requested URL returned error: %ld",
+			  results->http_code);
 	}
 
 	if (results->curl_result == CURLE_OK) {
@@ -1271,6 +1396,10 @@ static int handle_curl_result(struct slot_results *results)
 		} else {
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 			http_auth_methods &= ~CURLAUTH_GSSNEGOTIATE;
+			if (results->auth_avail) {
+				http_auth_methods &= results->auth_avail;
+				http_auth_methods_restricted = 1;
+			}
 #endif
 			return HTTP_REAUTH;
 		}
@@ -1292,8 +1421,8 @@ int run_one_slot(struct active_request_slot *slot,
 {
 	slot->results = results;
 	if (!start_active_slot(slot)) {
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "failed to start HTTP request");
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "failed to start HTTP request");
 		return HTTP_START_FAILED;
 	}
 
@@ -1563,6 +1692,9 @@ static int http_request(const char *url,
 		strbuf_addstr(&buf, " no-cache");
 	if (options && options->keep_error)
 		curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
+	if (options && options->initial_request &&
+	    http_follow_config == HTTP_FOLLOW_INITIAL)
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
 
 	headers = curl_slist_append(headers, buf.buf);
 
@@ -1611,16 +1743,16 @@ static int http_request(const char *url,
  *
  * Note that this assumes a sane redirect scheme. It's entirely possible
  * in the example above to end up at a URL that does not even end in
- * "info/refs".  In such a case we simply punt, as there is not much we can
- * do (and such a scheme is unlikely to represent a real git repository,
- * which means we are likely about to abort anyway).
+ * "info/refs".  In such a case we die. There's not much we can do, such a
+ * scheme is unlikely to represent a real git repository, and failing to
+ * rewrite the base opens options for malicious redirects to do funny things.
  */
 static int update_url_from_redirect(struct strbuf *base,
 				    const char *asked,
 				    const struct strbuf *got)
 {
 	const char *tail;
-	size_t tail_len;
+	size_t new_len;
 
 	if (!strcmp(asked, got->buf))
 		return 0;
@@ -1629,14 +1761,16 @@ static int update_url_from_redirect(struct strbuf *base,
 		die("BUG: update_url_from_redirect: %s is not a superset of %s",
 		    asked, base->buf);
 
-	tail_len = strlen(tail);
-
-	if (got->len < tail_len ||
-	    strcmp(tail, got->buf + got->len - tail_len))
-		return 0; /* insane redirect scheme */
+	new_len = got->len;
+	if (!strip_suffix_mem(got->buf, &new_len, tail))
+		die(_("unable to update url base from redirection:\n"
+		      "  asked for: %s\n"
+		      "   redirect: %s"),
+		    asked, got->buf);
 
 	strbuf_reset(base);
-	strbuf_add(base, got->buf, got->len - tail_len);
+	strbuf_add(base, got->buf, new_len);
+
 	return 1;
 }
 
@@ -1646,6 +1780,9 @@ static int http_request_reauth(const char *url,
 {
 	int ret = http_request(url, result, target, options);
 
+	if (ret != HTTP_OK && ret != HTTP_REAUTH)
+		return ret;
+
 	if (options && options->effective_url && options->base_url) {
 		if (update_url_from_redirect(options->base_url,
 					     url, options->effective_url)) {
@@ -1984,7 +2121,7 @@ static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
 		if (c != CURLE_OK)
 			die("BUG: curl_easy_getinfo for HTTP code failed: %s",
 				curl_easy_strerror(c));
-		if (slot->http_code >= 400)
+		if (slot->http_code >= 300)
 			return size;
 	}