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[PATCH 3/2] doc/http-backend: match query-string in apache half-auth example

From
Jeff King <peff@peff.net>
Date
Apr 13, 2013, 03:33 UTC
Message-ID
<20130413033336.GA20333@sigill.intra.peff.net>
In-Reply-To
<20130411170233.GB1255@sigill.intra.peff.net>

When setting up a "half-auth" repository in which reads can be done anonymously but writes require authentication, it is best if the server can require authentication for both the ref advertisement and the actual receive-pack POSTs. This alleviates the need for the admin to set http.receivepack in the repositories, and means that the client is challenged for credentials immediately, instead of partway through the push process (and git clients older than v1.7.11.7 had trouble handling these challenges).

Since detecting a push during the ref advertisement requires matching the query string, and this is non-trivial to do in Apache, we have traditionally punted and instructed users to just protect "/git-receive-pack$". This patch provides the mod_rewrite recipe to actually match the ref advertisement, which is preferred.

While we're at it, let's add the recipe to our test scripts so that we can be sure that it works, and doesn't get broken (either by our changes or by changes in Apache).

Signed-off-by: Jeff King <peff@peff.net>
---
This is on top of the jk/doc-http-backend topic.

Note that I have never used this in production, but it was pieced together from various advice I found on the web, and I did confirm that it works.

I kind of assume mod-rewrite is everywhere these days, so we could potentially drop the fallback config completely, as it is likely to confuse people.

 Documentation/git-http-backend.txt | 32 ++++++++++++++++++++++++--------
 t/lib-httpd/apache.conf            | 18 ++++++++++++++++++
 t/t5541-http-push.sh               | 30 ++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+), 8 deletions(-)
diff --git a/Documentation/git-http-backend.txt b/Documentation/git-http-backend.txt
index cad18ce..e3bcdb5 100644
--- a/Documentation/git-http-backend.txt
+++ b/Documentation/git-http-backend.txt
@@ -80,7 +80,30 @@ To enable anonymous read access but authenticated write access,
 ----------------------------------------------------------------
 +
 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$">
@@ -207,13 +230,6 @@ auth.require = (
 # ...and set up auth.backend here
 ----------------------------------------------------------------
 +
-Note that unlike the similar setup with Apache, we can easily match the
-query string for receive-pack, catching the initial request from the
-client. This means that the server administrator does not have to worry
-about configuring `http.receivepack` for the repositories (the default
-value, which enables it only in the case of authentication, is
-sufficient).
-+
 To require authentication for both reads and writes:
 +
 ----------------------------------------------------------------
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index 938b4cf..542241b 100644
--- a/t/lib-httpd/apache.conf
+++ b/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
diff --git a/t/t5541-http-push.sh b/t/t5541-http-push.sh
index 4086f02..beb00be 100755
--- a/t/t5541-http-push.sh
+++ b/t/t5541-http-push.sh
@@ -294,5 +294,35 @@ 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
-- 
1.8.2.rc0.33.gd915649
Previous: Jakub NarębskiNext: Jakub Narębski
Message 18 of 23 in “git-http-backend: anonymous read, authenticated write”
  1. Magnus TherningApr 9, 2013
  2. Jakub NarębskiApr 9, 2013
  3. Magnus TherningApr 10, 2013
  4. Jeff KingApr 9, 2013
  5. Magnus TherningApr 10, 2013
  6. Jeff KingApr 10, 2013
  7. Jakub NarębskiApr 10, 2013
  8. Jeff KingApr 10, 2013
  9. Magnus TherningApr 10, 2013
  10. Jeff KingApr 11, 2013
  11. 0/2 http-backend documentation examplesJeff King, Apr 11, 2013
  12. 1/2 doc/http-backend: clarify "half-auth" repo configurationJeff King, Apr 11, 2013
  13. Magnus TherningApr 11, 2013
  14. 2/2 doc/http-backend: give some lighttpd config examplesJeff King, Apr 11, 2013
  15. Jakub NarębskiApr 11, 2013
  16. Jeff KingApr 11, 2013
  17. Jakub NarębskiApr 11, 2013
  18. 3/2 doc/http-backend: match query-string in apache half-auth exampleJeff King, Apr 13, 2013
  19. Jakub NarębskiApr 13, 2013
  20. Magnus TherningApr 11, 2013
  21. Jeff KingApr 11, 2013
  22. Magnus TherningApr 12, 2013
  23. Jakub NarębskiApr 11, 2013

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