slop: Migrate to Docker Hardened images

base/Dockerfile

@@ -1,23 +1,50 @@
-FROM alpine:3.23
+# Build stage: the Docker Hardened "-dev" variant ships a shell + apk, which we
+# need to create the skpr user, lay down our config and prepare the writable
+# runtime directories. The results are copied into the minimal (shell-less)
+# runtime image below.
+FROM dhi.io/nginx:1.30-alpine3.23-dev AS build
+
+USER root
+
+# Create the skpr user (uid 1000) used for non-root, read-only execution.
 RUN adduser -D -u 1000 skpr
-RUN apk --update --no-cache add util-linux ca-certificates nginx nginx-mod-http-headers-more
+
+# CA certificates for TLS to upstreams (parity with the previous image).
+RUN apk --update --no-cache add ca-certificates
 
 COPY --chown=skpr:skpr etc /etc
 
-# We need to create and chown these directory for
-# readonly and non-root execution.
-RUN mkdir -p /run/nginx /var/tmp/nginx
-RUN ln -sf /dev/stderr /var/log/nginx/error.log
-RUN chown -R skpr:skpr /var/lib/nginx \
-                       /var/log/nginx \
-                       /var/tmp/nginx \
-                       /var/lib/nginx/tmp \
-                       /var/lib/nginx/logs \
-                       /usr/lib/nginx/modules \
-                       /run/nginx
-
-# Declaring these here means they inherit the "chown"
-# directive from above.
+# Create and chown the directories nginx writes to at runtime so the image can
+# run non-root against a read-only root filesystem. Paths match the nginx.conf
+# pid / *_temp_path directives.
+RUN mkdir -p /run/nginx /var/tmp/nginx /var/lib/nginx/tmp \
+    && ln -sf /dev/stderr /var/log/nginx/error.log \
+    && chown -R skpr:skpr /run/nginx \
+                          /var/tmp/nginx \
+                          /var/lib/nginx \
+                          /var/log/nginx \
+                          /etc/nginx
+
+# Runtime stage: minimal Docker Hardened Image, no shell or package manager.
+# Tag floats nginx 1.30.x patches + alpine 3.23 rebuilds (stable stream); switch
+# to 1.31-alpine3.23 for the mainline stream. Keep both stages on the same tag.
+FROM dhi.io/nginx:1.30-alpine3.23
+
+# Carry over the skpr user so nginx runs as uid 1000 and downstream images can
+# COPY --chown=skpr.
+COPY --from=build /etc/passwd /etc/group /etc/
+
+# CA certificates for TLS to upstreams.
+COPY --from=build /etc/ssl/certs /etc/ssl/certs
+
+# Config and the pre-chowned writable directories.
+COPY --from=build --chown=1000:1000 /etc/nginx /etc/nginx
+COPY --from=build --chown=1000:1000 /run/nginx /run/nginx
+COPY --from=build --chown=1000:1000 /var/tmp/nginx /var/tmp/nginx
+COPY --from=build --chown=1000:1000 /var/lib/nginx /var/lib/nginx
+COPY --from=build --chown=1000:1000 /var/log/nginx /var/log/nginx
+
+# Declaring these here means they inherit the "chown" directive from above.
 VOLUME /run/nginx
 VOLUME /var/tmp/nginx
 VOLUME /var/lib/nginx/tmp
@@ -28,4 +55,8 @@ STOPSIGNAL SIGTERM
 
 USER skpr
 
+# The DHI runtime image sets ENTRYPOINT ["nginx"] and CMD ["-g", "daemon off;"].
+# Reset both so our single "nginx" invocation runs with "daemon off;" from
+# nginx.conf, matching the previous image and avoiding a duplicate directive.
+ENTRYPOINT []
 CMD ["nginx"]

base/etc/nginx/conf.d/header/server.conf

@@ -1 +1,3 @@
-more_clear_headers Server;
+# The Server header cannot be fully removed with stock nginx; that previously
+# relied on the headers-more module (more_clear_headers Server). "server_tokens
+# off" (set in nginx.conf) hides the version, leaving only "Server: nginx".

base/etc/nginx/nginx.conf

@@ -2,6 +2,10 @@ daemon off;
 
 worker_processes 1;
 
+# Written to a skpr-owned directory so nginx can run non-root with a read-only
+# root filesystem (the base image's default pid path is not writable by skpr).
+pid /run/nginx/nginx.pid;
+
 include /etc/nginx/modules/*.conf;
 
 events {
@@ -16,6 +20,14 @@ http {
   include /etc/nginx/mime.types;
   default_type application/octet-stream;
 
+  # Temporary paths in a skpr-owned directory so nginx can run non-root with a
+  # read-only root filesystem (the base image's defaults are not writable by skpr).
+  client_body_temp_path /var/lib/nginx/tmp/client_body;
+  proxy_temp_path       /var/lib/nginx/tmp/proxy;
+  fastcgi_temp_path     /var/lib/nginx/tmp/fastcgi;
+  uwsgi_temp_path       /var/lib/nginx/tmp/uwsgi;
+  scgi_temp_path        /var/lib/nginx/tmp/scgi;
+
   server_tokens off;
 
   keepalive_timeout 65;

drupal/dev/Dockerfile

@@ -1,4 +1,6 @@
 FROM from_image
 
-RUN rm -f /etc/nginx/conf.d/header/x_drupal_cache.conf
-RUN rm -f /etc/nginx/conf.d/header/x_drupal_dynamic_cache.conf
+# Leave the Drupal cache headers visible for dev images. These empty overrides
+# replace the production fastcgi_hide_header directives (shell-free so they work
+# on the no-shell hardened base image).
+COPY --chown=skpr:skpr etc /etc

drupal/dev/etc/nginx/conf.d/header/x_drupal_cache.conf

@@ -0,0 +1,2 @@
+# Intentionally empty for dev images: the X-Drupal-Cache header is left visible
+# (production hides it via fastcgi_hide_header). Overrides the base file.

drupal/dev/etc/nginx/conf.d/header/x_drupal_dynamic_cache.conf

@@ -0,0 +1,2 @@
+# Intentionally empty for dev images: the X-Drupal-Dynamic-Cache header is left
+# visible (production hides it via fastcgi_hide_header). Overrides the base file.

drupal/etc/nginx/conf.d/header/x_drupal_cache.conf

@@ -1 +1 @@
-more_clear_headers X-Drupal-Cache;
+fastcgi_hide_header X-Drupal-Cache;

drupal/etc/nginx/conf.d/header/x_drupal_dynamic_cache.conf

@@ -1 +1 @@
-more_clear_headers X-Drupal-Dynamic-Cache;
+fastcgi_hide_header X-Drupal-Dynamic-Cache;

drupal/etc/nginx/conf.d/header/x_generator.conf

@@ -1 +1 @@
-more_clear_headers X-Generator;
+fastcgi_hide_header X-Generator;

php-fpm/dev/Dockerfile

@@ -1,6 +1,6 @@
 FROM from_image
 
+# Allow errors to be displayed for non production PHP images. The dev copy of
+# 10-error-page.conf disables the error_page 500 interception (shell-free so it
+# works on the no-shell hardened base image).
 COPY --chown=skpr:skpr etc /etc
-
-# Allow errors to be displayed for non production PHP images.
-RUN sed -i '/error_page 500/s/^/#/' /etc/nginx/conf.d/location/10-error-page.conf

php-fpm/dev/etc/nginx/conf.d/location/10-error-page.conf

@@ -0,0 +1,15 @@
+error_page 400 /error-pages/400.html;
+#error_page 403 /error-pages/403.html;
+#error_page 404 /error-pages/404.html;
+error_page 405 /error-pages/405.html;
+error_page 414 /error-pages/414.html;
+error_page 416 /error-pages/416.html;
+error_page 418 /error-pages/418.html;
+# error_page 500 is intentionally disabled for dev images so PHP errors are
+# displayed instead of the static 500 page. Keep the rest in sync with
+# base/etc/nginx/conf.d/location/10-error-page.conf.
+#error_page 500 /error-pages/500.html;
+error_page 501 /error-pages/501.html;
+error_page 502 /error-pages/502.html;
+error_page 503 /error-pages/503.html;
+error_page 504 /error-pages/504.html;