Merge branch 'jk/doc-http-backend' into maint

Improve documentation to illustrate "push authenticated, fetch
anonymous" configuration for smart HTTP servers.

* jk/doc-http-backend:
  doc/http-backend: match query-string in apache half-auth example
  doc/http-backend: give some lighttpd config examples
  doc/http-backend: clarify "half-auth" repo configuration

Documentation/git-http-backend.txt

@@ -80,7 +80,30 @@ ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
 ----------------------------------------------------------------
 +
 To enable anonymous read access but authenticated write access,
-require authorization with a LocationMatch directive:
+require authorization for both the initial ref advertisement (which we
+detect as a push via the service parameter in the query string), and the
+receive-pack invocation itself:
++
+----------------------------------------------------------------
+RewriteCond %{QUERY_STRING} service=git-receive-pack [OR]
+RewriteCond %{REQUEST_URI} /git-receive-pack$
+RewriteRule ^/git/ - [E=AUTHREQUIRED:yes]
+
+<LocationMatch "^/git/">
+	Order Deny,Allow
+	Deny from env=AUTHREQUIRED
+
+	AuthType Basic
+	AuthName "Git Access"
+	Require group committers
+	Satisfy Any
+	...
+</LocationMatch>
+----------------------------------------------------------------
++
+If you do not have `mod_rewrite` available to match against the query
+string, it is sufficient to just protect `git-receive-pack` itself,
+like:
 +
 ----------------------------------------------------------------
 <LocationMatch "^/git/.*/git-receive-pack$">
@@ -91,6 +114,15 @@ require authorization with a LocationMatch directive:
 </LocationMatch>
 ----------------------------------------------------------------
 +
+In this mode, the server will not request authentication until the
+client actually starts the object negotiation phase of the push, rather
+than during the initial contact.  For this reason, you must also enable
+the `http.receivepack` config option in any repositories that should
+accept a push. The default behavior, if `http.receivepack` is not set,
+is to reject any pushes by unauthenticated users; the initial request
+will therefore report `403 Forbidden` to the client, without even giving
+an opportunity for authentication.
++
 To require authentication for both reads and writes, use a Location
 directive around the repository, or one of its parent directories:
 +
@@ -158,6 +190,54 @@ ScriptAliasMatch \
 ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/
 ----------------------------------------------------------------
 
+Lighttpd::
+	Ensure that `mod_cgi`, `mod_alias, `mod_auth`, `mod_setenv` are
+	loaded, then set `GIT_PROJECT_ROOT` appropriately and redirect
+	all requests to the CGI:
++
+----------------------------------------------------------------
+alias.url += ( "/git" => "/usr/lib/git-core/git-http-backend" )
+$HTTP["url"] =~ "^/git" {
+	cgi.assign = ("" => "")
+	setenv.add-environment = (
+		"GIT_PROJECT_ROOT" => "/var/www/git",
+		"GIT_HTTP_EXPORT_ALL" => ""
+	)
+}
+----------------------------------------------------------------
++
+To enable anonymous read access but authenticated write access:
++
+----------------------------------------------------------------
+$HTTP["querystring"] =~ "service=git-receive-pack" {
+	include "git-auth.conf"
+}
+$HTTP["url"] =~ "^/git/.*/git-receive-pack$" {
+	include "git-auth.conf"
+}
+----------------------------------------------------------------
++
+where `git-auth.conf` looks something like:
++
+----------------------------------------------------------------
+auth.require = (
+	"/" => (
+		"method" => "basic",
+		"realm" => "Git Access",
+		"require" => "valid-user"
+	       )
+)
+# ...and set up auth.backend here
+----------------------------------------------------------------
++
+To require authentication for both reads and writes:
++
+----------------------------------------------------------------
+$HTTP["url"] =~ "^/git/private" {
+	include "git-auth.conf"
+}
+----------------------------------------------------------------
+
 
 ENVIRONMENT
 -----------

t/lib-httpd/apache.conf

@@ -40,6 +40,9 @@ ErrorLog error.log
 <IfModule !mod_authz_user.c>
 	LoadModule authz_user_module modules/mod_authz_user.so
 </IfModule>
+<IfModule !mod_authz_host.c>
+	LoadModule authz_host_module modules/mod_authz_host.so
+</IfModule>
 </IfVersion>
 
 PassEnv GIT_VALGRIND
@@ -110,6 +113,21 @@ SSLEngine On
 	Require valid-user
 </LocationMatch>
 
+RewriteCond %{QUERY_STRING} service=git-receive-pack [OR]
+RewriteCond %{REQUEST_URI} /git-receive-pack$
+RewriteRule ^/half-auth-complete/ - [E=AUTHREQUIRED:yes]
+
+<Location /half-auth-complete/>
+  Order Deny,Allow
+  Deny from env=AUTHREQUIRED
+
+  AuthType Basic
+  AuthName "Git Access"
+  AuthUserFile passwd
+  Require valid-user
+  Satisfy Any
+</Location>
+
 <IfDefine DAV>
 	LoadModule dav_module modules/mod_dav.so
 	LoadModule dav_fs_module modules/mod_dav_fs.so

t/t5541-http-push.sh

@@ -295,5 +295,35 @@ test_expect_success 'push to auth-only-for-push repo' '
 	test_cmp expect actual
 '
 
+test_expect_success 'create repo without http.receivepack set' '
+	cd "$ROOT_PATH" &&
+	git init half-auth &&
+	(
+		cd half-auth &&
+		test_commit one
+	) &&
+	git clone --bare half-auth "$HTTPD_DOCUMENT_ROOT_PATH/half-auth.git"
+'
+
+test_expect_success 'clone via half-auth-complete does not need password' '
+	cd "$ROOT_PATH" &&
+	set_askpass wrong &&
+	git clone "$HTTPD_URL"/half-auth-complete/smart/half-auth.git \
+		half-auth-clone &&
+	expect_askpass none
+'
+
+test_expect_success 'push into half-auth-complete requires password' '
+	cd "$ROOT_PATH/half-auth-clone" &&
+	echo two >expect &&
+	test_commit two &&
+	set_askpass user@host &&
+	git push "$HTTPD_URL/half-auth-complete/smart/half-auth.git" &&
+	git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/half-auth.git" \
+		log -1 --format=%s >actual &&
+	expect_askpass both user@host &&
+	test_cmp expect actual
+'
+
 stop_httpd
 test_done