Harden container startup (#24718)

* keep /config out of the root environment in the frigate run script

The script exported HOME=/config and prepended /config/.local/lib to LD_LIBRARY_PATH while still root, then ran python3, ffmpeg, grep, and opt_in_out as root. The runtime user owns /config, so it could plant a .pth file in the user site-packages or a library on the loader path and get code run as root on the next start. Root helpers now run with root's environment (and python3 -I), and HOME, LD_LIBRARY_PATH, and PATH reach only the dropped process through env on the s6-setuidgid line. opt_in_out runs as the runtime user, so the openvino marker no longer gets written into /config by root.

* don't follow a planted symlink when writing /dev/shm/go2rtc.yaml

After the first start the go2rtc user owned /dev/shm/go2rtc.yaml and could swap it for a dangling symlink. The run script's -f test was false for a dangling link, so the link survived, and root's create_config.py then created the link target and the chown handed it to go2rtc. The run script now removes any existing entry, create_config.py creates the file with O_EXCL and O_NOFOLLOW at mode 0640, and the chown uses -h.

* run root python helpers in isolated mode and keep HOME=/config for non-root containers

The previous commit only set HOME=/config when dropping from root, so a container started with --user lost it. The other root-run helpers in the go2rtc, nginx, and certsync scripts now use python3 -I too, so they never load user site-packages or PYTHON* variables.

* validate networking.listen values before rendering them into nginx config

ListenConfig and get_nginx_settings.py only checked that the text after the last colon parsed as an int, and tempio rendered the raw string into the listen directive, so a value like "5000; location /x/ { alias /; } #:5000" injected nginx directives. Both now go through parse_listen_address, which accepts only a port, IPv4:port, or [IPv6]:port with a 1 to 65535 port and rebuilds the value from the parsed parts. get_nginx_settings.py falls back to the default port on an invalid value so nginx still serves the safe-mode UI.

* tighten comments

* accept hostnames, wildcards, and padded values in networking.listen

The stricter parser broke localhost:5000, *:5000, and values with surrounding whitespace that the old int() parsing accepted. parse_listen_address now strips the value and accepts RFC 1123 hostnames and *, still rebuilding the rendered value from the parsed parts. The ListenConfig validator runs in before mode, because pydantic coerced true to port 1 while get_nginx_settings.py rejected it and fell back to 5000, so the auth internal port and nginx disagreed.

* always create go2rtc.yaml after removing it and don't let opt_in_out stop frigate

The go2rtc else-branch was only reachable when a regular file was planted between rm and the test, and then loaded that file as go2rtc's config. create_config.py now runs unconditionally and its exclusive create fails closed. opt_in_out runs after s6-svc -O, so a failure there was terminal under errexit.

* fall back to default listen ports when either is invalid or they collide

* keep valid listen values and refuse to start nginx when the ports collide

docker/main/rootfs/usr/local/nginx/get_nginx_settings.py

@@ -8,7 +8,7 @@ from typing import Any
 from ruamel.yaml import YAML
 
 sys.path.insert(0, "/opt/frigate")
-from frigate.util.config import find_config_file
+from frigate.util.config import find_config_file, parse_listen_address
 
 sys.path.remove("/opt/frigate")
 
@@ -35,20 +35,29 @@ ipv6_config: dict[str, Any] = networking_config.get("ipv6", {})
 ipv6_config.setdefault("enabled", False)
 
 listen_config: dict[str, Any] = networking_config.get("listen", {})
-listen_config.setdefault("internal", 5000)
-listen_config.setdefault("external", 8971)
 
-# handle case where internal port is a string with ip:port
-internal_port = listen_config["internal"]
-if type(internal_port) is str:
-    internal_port = int(internal_port.split(":")[-1])
-listen_config["internal_port"] = internal_port
+# Frigate's own validation runs elsewhere, and a bad value here must not stop nginx
+# from serving the safe-mode UI. Valid values are kept so a fallback never widens
+# the unauthenticated internal listener beyond the configured address.
+for key, default in (("internal", 5000), ("external", 8971)):
+    try:
+        value, port = parse_listen_address(listen_config.get(key, default))
+    except ValueError:
+        print(
+            f"[WARN] Invalid networking.listen.{key}, using {default}",
+            file=sys.stderr,
+        )
+        value, port = default, default
 
-# handle case where external port is a string with ip:port
-external_port = listen_config["external"]
-if type(external_port) is str:
-    external_port = int(external_port.split(":")[-1])
-listen_config["external_port"] = external_port
+    listen_config[key] = value
+    listen_config[f"{key}_port"] = port
+
+if listen_config["internal_port"] == listen_config["external_port"]:
+    print(
+        "[ERROR] networking.listen.internal and external share a port",
+        file=sys.stderr,
+    )
+    sys.exit(1)
 
 base_path = os.environ.get("FRIGATE_BASE_PATH", "")