Run nginx as the frigate user with writable state in /tmp/nginx

.github/workflows/ci.yml

@@ -91,7 +91,7 @@ jobs:
             echo "response carries frame-ancestors, which breaks cross-origin iframe embedding"
             exit 1
           fi
-          docker exec frigate /usr/local/nginx/sbin/nginx -t
+          docker exec frigate /usr/local/nginx/sbin/nginx -t -c /tmp/nginx/conf/nginx.conf
           docker exec frigate stat -c %a /etc/letsencrypt/live/frigate/privkey.pem | grep -qx 600
           docker exec frigate stat -c %a /dev/shm/go2rtc.yaml | grep -qx 640
       - name: Assert PUID/PGID remapping

docker/main/rootfs/etc/s6-overlay/s6-rc.d/certsync/run

@@ -49,7 +49,7 @@ do
     then
         echo "[INFO] Reloading nginx to refresh TLS certificate"
         echo "$lefile: $leprint"
-        /usr/local/nginx/sbin/nginx -s reload
+        /usr/local/nginx/sbin/nginx -c /tmp/nginx/conf/nginx.conf -s reload
     fi
 
     sleep 60

docker/main/rootfs/etc/s6-overlay/s6-rc.d/nginx/data/check

@@ -2,4 +2,4 @@
 set -e
 
 # Wait for PID file to exist.
-while ! test -f /run/nginx.pid; do sleep 1; done
+while ! test -f /tmp/nginx/nginx.pid; do sleep 1; done

docker/main/rootfs/etc/s6-overlay/s6-rc.d/nginx/run

@@ -59,10 +59,14 @@ function set_worker_processes() {
         cpus=4
     fi
 
-    # we need to catch any errors because sed will fail if user has bind mounted a custom nginx file
-    sed -i "s/worker_processes auto;/worker_processes ${cpus};/" /usr/local/nginx/conf/nginx.conf || true
+    sed -i "s/worker_processes auto;/worker_processes ${cpus};/" /tmp/nginx/conf/nginx.conf
 }
 
+# copied whole so the conf tree's relative includes still resolve
+mkdir -p /tmp/nginx/conf /tmp/nginx/client_body /tmp/nginx/proxy \
+         /tmp/nginx/fastcgi /tmp/nginx/uwsgi /tmp/nginx/scgi
+cp -r /usr/local/nginx/conf/. /tmp/nginx/conf/
+
 set_worker_processes
 
 # ensure the directory for ACME challenges exists
@@ -87,15 +91,29 @@ nginx_settings=$(python3 /usr/local/nginx/get_nginx_settings.py)
 # build templates for optional FRIGATE_BASE_PATH environment variable
 echo "$nginx_settings" | \
     tempio -template /usr/local/nginx/templates/base_path.gotmpl \
-           -out /usr/local/nginx/conf/base_path.conf
+           -out /tmp/nginx/conf/base_path.conf
 
 # build templates for additional network settings
 echo "$nginx_settings" | \
     tempio -template /usr/local/nginx/templates/listen.gotmpl \
-           -out /usr/local/nginx/conf/listen.conf
+           -out /tmp/nginx/conf/listen.conf
+
+if [[ "$(id -u)" -eq 0 && "${FRIGATE_RUN_AS_ROOT:-false}" != "true" ]]; then
+    chown -R frigate:frigate /tmp/nginx
+    # only the self-signed key we just generated; user-mounted certs may be :ro
+    if [ -f "$letsencrypt_path/privkey.pem" ]; then
+        chown frigate:frigate "$letsencrypt_path/privkey.pem" "$letsencrypt_path/fullchain.pem" 2>/dev/null || true
+    fi
+fi
 
 # Replace the bash process with the NGINX process, redirecting stderr to stdout
 exec 2>&1
-exec \
-    s6-notifyoncheck -t 30000 -n 1 \
-    nginx
+if [[ "$(id -u)" -ne 0 || "${FRIGATE_RUN_AS_ROOT:-false}" == "true" ]]; then
+    exec \
+        s6-notifyoncheck -t 30000 -n 1 \
+        nginx -c /tmp/nginx/conf/nginx.conf
+else
+    exec \
+        s6-notifyoncheck -t 30000 -n 1 \
+        s6-setuidgid frigate nginx -c /tmp/nginx/conf/nginx.conf
+fi

docker/main/rootfs/usr/local/nginx/conf/nginx.conf

@@ -1,9 +1,15 @@
+# Copied to /tmp/nginx/conf at startup and loaded with -c from there. Relative
+# includes resolve against the -c file, but every other path directive resolves
+# against the compile-time --prefix, so non-include paths must stay absolute.
+
 daemon off;
+# Ignored by a non-root master; required by FRIGATE_RUN_AS_ROOT so workers
+# stay root instead of the compiled-in default user
 user root;
 worker_processes auto;
 
 error_log /dev/stdout warn;
-pid /var/run/nginx.pid;
+pid /tmp/nginx/nginx.pid;
 
 events {
     worker_connections 1024;
@@ -13,6 +19,12 @@ http {
     map_hash_bucket_size 256;
     server_tokens off;
 
+    client_body_temp_path /tmp/nginx/client_body;
+    proxy_temp_path /tmp/nginx/proxy;
+    fastcgi_temp_path /tmp/nginx/fastcgi;
+    uwsgi_temp_path /tmp/nginx/uwsgi;
+    scgi_temp_path /tmp/nginx/scgi;
+
     include mime.types;
     default_type application/octet-stream;