Refresh the server configs and drop `unsafe-inline`

The inline handlers and the auto-submitting selects are gone, so
`script-src` no longer needs it, and t0004 now checks that the three
configs pin the same policy.

1 file changed, 30 insertions, 43 deletions

diff --git a/custom/servers/nginx.conf b/custom/servers/nginx.conf
index cf1e49f..3ffa2ba 100644
--- a/custom/servers/nginx.conf
+++ b/custom/servers/nginx.conf
@@ -16,8 +16,7 @@
 # PATH_INFO and reads page options such as h= and id= from QUERY_STRING, so
 # nginx must pass PATH_INFO through to the binary. cgit builds its own link
 # base from SCRIPT_NAME. The five static assets are served straight off disk
-# and must never be routed through cgit. Passing PATH_INFO through is the
-# single most important part of the config below.
+# and must never be routed through cgit.
 #
 # nginx cannot run CGI programs itself, so a small bridge called fcgiwrap runs
 # the cgit.cgi binary and speaks FastCGI to nginx. Nothing below works until
@@ -48,11 +47,10 @@ events {
 
 
 http {
-    # nginx's compiled-in type table knows only text/html, and the usual
-    # "include mime.types" would pull in a second file. Exactly five static
-    # files are served off disk, so their types are declared here instead and
-    # this config keeps standing on its own. Everything else nginx returns
-    # comes from cgit, which sets its own Content-Type.
+    # nginx's built-in type table covers none of these five extensions, and
+    # the usual "include mime.types" would pull in a second file, so the five
+    # types are declared here. Everything else nginx returns comes from cgit,
+    # which sets its own Content-Type.
     types {
         text/css                  css;
         text/javascript           js;
@@ -80,14 +78,11 @@ http {
     gzip_types         text/css text/javascript text/plain application/atom+xml;
 
 
-    # Requests carrying a Host header this config does not serve, a raw IP or
-    # an invented name from a scanning bot, land in these two blocks and are
-    # dropped without a response. cgit keys its page cache on the Host header
-    # so clone URLs stay honest, which means every invented hostname reaching
-    # it would mint a cache entry of its own and evict a real page to make
-    # room. Refusing strangers here keeps the cache to the names the site
-    # actually answers to. 444 is nginx shorthand for closing the connection
-    # without replying.
+    # Requests carrying a Host header this config does not serve are dropped
+    # without a response. cgit keys its page cache on the Host header, so
+    # every invented hostname reaching it would mint a cache entry of its
+    # own and evict a real page. 444 is nginx shorthand for closing the
+    # connection without replying.
     server {
         listen      80 default_server;
         listen      [::]:80 default_server;
@@ -158,8 +153,9 @@ http {
         # Site-wide security headers sit here because they must also cover the
         # static assets nginx serves directly. cgit itself sends only the
         # headers the proxy cannot supply. Those are Status, Content-Type,
-        # Content-Length and Content-Disposition on downloads, a no-store
-        # Cache-Control on unauthenticated responses, the auth filter's
+        # Content-Length and Content-Disposition on downloads, Location on
+        # redirects, a no-store Cache-Control on unauthenticated responses,
+        # the auth filter's
         # Set-Cookie, and on raw repository bytes a nosniff of its own next to
         # the stricter policy "default-src 'none'". Everything else, this
         # policy included, is the proxy's job.
@@ -170,13 +166,13 @@ http {
         # construct that rewrites response headers here could strip the
         # protection cgit puts on raw repository content.
         #
-        # cgit loads only its own /cgit.js and uses inline style on the
-        # diffstat bars, so script-src stays self while style-src allows
-        # inline. form-action self covers the login form, the only form cgit
+        # form-action self covers the login form, the only form cgit
         # renders. always applies them to error responses too. If you enable
         # the gravatar or libravatar avatar filter, add its host to img-src,
         # for example https://www.gravatar.com or https://seccdn.libravatar.org.
-        add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; object-src 'none'; base-uri 'none'; frame-ancestors 'self'; form-action 'self'" always;
+        # A head-include or repo.head-content that injects a <style> block
+        # needs 'unsafe-inline' added to style-src.
+        add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' data:; object-src 'none'; base-uri 'none'; frame-ancestors 'self'; form-action 'self'" always;
         add_header X-Content-Type-Options "nosniff" always;
         add_header Referrer-Policy "no-referrer" always;
 
@@ -203,8 +199,7 @@ http {
 
         # The document root is the directory that holds the static assets. cgit
         # emits absolute links to /cgit.css and /cgit.png by default, so those
-        # files must resolve at the root of the URL space. Pointing root at the
-        # asset directory makes /cgit.css map to /usr/share/cgit/cgit.css.
+        # files must resolve at the root of the URL space.
         root /usr/share/cgit;
 
         # The only request body cgit ever reads is the auth-filter login form,
@@ -216,15 +211,11 @@ http {
         error_log  /var/log/nginx/cgit.error.log;
 
         # Match the assets by their exact root-level names, never by bare
-        # extension. cgit routes on PATH_INFO and a repository can hold files
-        # ending in .css or .png, so /myrepo/tree/style.css and /myrepo/plain/
-        # logo.png are real cgit URLs. A broad extension match would capture
-        # those, look for them on disk, and return 404 before cgit could render
-        # them. Anchoring the regex at the start of the path matches /cgit.css
-        # but not /myrepo/tree/cgit.css, so it can never shadow a repository
-        # file. An nginx regex location is matched before the prefix location
-        # below, so these assets win for their exact URLs and cgit wins for the
-        # rest.
+        # extension. A repository can hold files ending in .css or .png, and
+        # /myrepo/tree/style.css is a real cgit URL a broad match would
+        # capture and 404. The regex anchored at ^/ matches /cgit.css but
+        # never /myrepo/tree/cgit.css, and a regex location beats the prefix
+        # location below, so assets win their exact URLs and cgit the rest.
         location ~ ^/(cgit\.css|cgit\.js|cgit\.png|favicon\.ico|robots\.txt)$ {
             expires    30d;
             access_log off;
@@ -234,13 +225,10 @@ http {
         # Everything that is not a static asset above is a cgit URL, the repo
         # index, a repository, a page within a repository, a snapshot, a feed.
         location / {
-            # The CGI environment. This is normally "include fastcgi_params",
-            # which would be a second file, so the list is written out here.
-            # Of all of it cgit itself reads only CGIT_CONFIG, PATH_INFO,
-            # QUERY_STRING, SCRIPT_NAME, REQUEST_METHOD, CONTENT_LENGTH,
-            # HTTP_HOST, HTTPS, SERVER_NAME, SERVER_PORT, HTTP_COOKIE and
-            # HTTP_REFERER. The cookie and referer arrive on their own, since
-            # nginx forwards request headers as HTTP_* without being asked.
+            # The CGI environment, normally "include fastcgi_params", written
+            # out here so this config stands alone. The cookie and referer
+            # arrive on their own, since nginx forwards request headers as
+            # HTTP_* without being asked.
 
             # The program fcgiwrap runs. It must be the cgit binary itself, not
             # $document_root$fastcgi_script_name, which would try to run a repo
@@ -291,8 +279,7 @@ http {
             fastcgi_param SERVER_PORT       $server_port;
             fastcgi_param SERVER_NAME       $server_name;
 
-            # Hand off to the fcgiwrap socket. A TCP fcgiwrap would use for
-            # example 127.0.0.1:9000 here.
+            # Hand off to the fcgiwrap socket.
             fastcgi_pass unix:/run/fcgiwrap.socket;
 
             # Large outputs such as snapshot tarballs and blame on big files
@@ -300,8 +287,8 @@ http {
             fastcgi_read_timeout 300s;
             fastcgi_buffering off;
 
-            # cgit sends no caching headers of its own, so browsers refetch
-            # dynamic pages and cgit's internal cache keeps that cheap. Do not
+            # Ordinary cgit pages carry no caching headers, so browsers
+            # refetch them and cgit's internal cache keeps that cheap. Do not
             # add a blanket expires or Cache-Control in this location. It
             # would fight the no-store cgit puts on the login page and could
             # let one visitor's page be served to another from a shared cache.