Normalize request paths in media auth (#24662)

* merge repeated slashes in the media auth path check

X-Original-URL carries only the raw request path since #24602, and extract_path parsed it with urlparse, which reads a path starting with // as a host. A restricted role could request another camera's clips or recordings with a leading // and the media check saw a non-media path and allowed it, while nginx merged the slashes and served the file. extract_path now splits the raw URI the same way the go2rtc stream check does and merges repeated slashes as nginx does before matching locations. The split helper moves from auth.py into media_auth.py so both checks share it.

* check the nginx-normalized path in the media auth dot-segment fallback

The dot-segment fallback only checked the raw first segment, so a role restricted to one camera could request `/x/../clips/back_door-1.jpg` and nginx served back_door's clip. The fallback now resolves the path the way nginx does before checking for a media root, and the URI split ends at a literal `#` since nginx ignores everything after it.

frigate/api/auth.py

@@ -11,7 +11,7 @@ import secrets
 import time
 from datetime import datetime
 from pathlib import Path
-from urllib.parse import parse_qs, unquote
+from urllib.parse import parse_qs
 
 import requests
 from fastapi import APIRouter, Depends, HTTPException, Request, Response
@@ -31,6 +31,8 @@ from frigate.api.media_auth import (
     check_camera_access,
     deny_response_for_media_uri,
     is_role_restricted,
+    normalize_request_path,
+    split_request_uri,
 )
 from frigate.config import AuthConfig, ProxyConfig
 from frigate.const import CONFIG_DIR, JWT_SECRET_ENV_VAR, PASSWORD_HASH_ALGORITHM
@@ -1185,37 +1187,6 @@ GO2RTC_STREAM_PROXY_PATHS = frozenset(
     }
 )
 
-_URI_SCHEME_AND_AUTHORITY = re.compile(r"^[A-Za-z][A-Za-z0-9+.-]*://[^/?]*")
-
-
-def _split_request_uri(request_uri: str) -> tuple[str, str]:
-    """Split a raw request URI into its path and query string.
-
-    urlparse is not used since it reads a path starting with `//` as a host.
-    """
-    uri = _URI_SCHEME_AND_AUTHORITY.sub("", request_uri, count=1)
-    path, _, query = uri.partition("?")
-    return path, query
-
-
-def _normalize_request_path(path: str) -> str:
-    """Normalize a raw request path the way nginx does before matching locations.
-
-    nginx percent-decodes the path, merges repeated slashes and resolves dot
-    segments, while `X-Original-URL` carries the raw `$request_uri`.
-    """
-    segments: list[str] = []
-    for segment in unquote(path).split("/"):
-        if segment in ("", "."):
-            continue
-        if segment == "..":
-            if segments:
-                segments.pop()
-            continue
-        segments.append(segment)
-
-    return "/" + "/".join(segments)
-
 
 def _is_go2rtc_stream_proxy_request(path: str, request: Request) -> bool:
     # nginx marks requests routed through the go2rtc stream locations, and the
@@ -1223,7 +1194,7 @@ def _is_go2rtc_stream_proxy_request(path: str, request: Request) -> bool:
     if request.headers.get("x-go2rtc-stream-proxy") == "1":
         return True
 
-    normalized = _normalize_request_path(path)
+    normalized = normalize_request_path(path)
     return any(normalized.startswith(p) for p in GO2RTC_STREAM_PROXY_PATHS)
 
 
@@ -1242,7 +1213,7 @@ def deny_response_for_go2rtc_stream(
     if not original_url:
         return None
 
-    path, query = _split_request_uri(original_url)
+    path, query = split_request_uri(original_url)
     if not _is_go2rtc_stream_proxy_request(path, request):
         return None
 

frigate/api/media_auth.py

@@ -13,8 +13,9 @@ from __future__ import annotations
 
 import logging
 import os
+import re
 from enum import Enum
-from urllib.parse import unquote, urlparse
+from urllib.parse import unquote
 
 from peewee import DoesNotExist
 
@@ -24,6 +25,8 @@ from frigate.models import Export, User
 
 logger = logging.getLogger(__name__)
 
+_URI_SCHEME_AND_AUTHORITY = re.compile(r"^[A-Za-z][A-Za-z0-9+.-]*://[^/?]*")
+
 
 class MediaAuthResolution(str, Enum):
     """Classification of an `X-Original-URL` path for media-auth purposes."""
@@ -41,6 +44,36 @@ class MediaAuthResolution(str, Enum):
     UNKNOWN = "unknown"
 
 
+def split_request_uri(request_uri: str) -> tuple[str, str]:
+    """Split a raw request URI into its path and query string.
+
+    urlparse is not used since it reads a path starting with `//` as a host.
+    nginx ends the URI at a literal `#`, so anything after it is dropped.
+    """
+    uri = _URI_SCHEME_AND_AUTHORITY.sub("", request_uri, count=1)
+    path, _, query = uri.partition("#")[0].partition("?")
+    return path, query
+
+
+def normalize_request_path(path: str) -> str:
+    """Normalize a raw request path the way nginx does before matching locations.
+
+    nginx percent-decodes the path, merges repeated slashes and resolves dot
+    segments, while `X-Original-URL` carries the raw `$request_uri`.
+    """
+    segments: list[str] = []
+    for segment in unquote(path).split("/"):
+        if segment in ("", "."):
+            continue
+        if segment == "..":
+            if segments:
+                segments.pop()
+            continue
+        segments.append(segment)
+
+    return "/" + "/".join(segments)
+
+
 def extract_path(original_url: str | None) -> str | None:
     """Return the decoded path component of nginx's `X-Original-URL` header.
 
@@ -49,14 +82,14 @@ def extract_path(original_url: str | None) -> str | None:
     request like `/recordings/.../allowed_cam/../forbidden_cam/file.mp4`
     would (1) parse as the allowed camera in our auth check, (2) be served
     as the forbidden camera by nginx. To close the bypass we reject any URI
-    whose path contains `.` or `..` segments outright.
+    whose path contains `.` or `..` segments outright. Repeated slashes are
+    merged, as nginx does before matching locations.
     """
     if not original_url:
         return None
 
-    parsed = urlparse(original_url)
+    path, _ = split_request_uri(original_url)
-    raw_path = parsed.path or original_url
+    decoded = re.sub(r"/{2,}", "/", unquote(path))
-    decoded = unquote(raw_path)
     if not decoded:
         return None
 
@@ -252,12 +285,11 @@ def deny_response_for_media_uri(
     path = extract_path(original_url)
 
     # `extract_path` returns None for URIs containing `.` or `..` segments.
-    # For media-root URIs that's a traversal attempt — deny outright. For
+    # Deny them when nginx would resolve them under a media root, and pass
-    # non-media URIs, pass through (nginx / the backend handle them).
+    # the rest through to nginx and the backend.
     if path is None:
-        raw = urlparse(original_url).path or original_url
+        normalized = normalize_request_path(split_request_uri(original_url)[0])
-        decoded = unquote(raw)
+        first = normalized.lstrip("/").split("/", 1)[0]
-        first = decoded.lstrip("/").split("/", 1)[0] if decoded else ""
         if first in ("clips", "recordings", "exports"):
             return 403
         return None

frigate/test/test_media_auth.py

@@ -76,6 +76,20 @@ class TestExtractPath(unittest.TestCase):
         self.assertIsNone(extract_path(None))
         self.assertIsNone(extract_path(""))
 
+    def test_leading_double_slash_is_path(self):
+        self.assertEqual(
+            extract_path("//clips/front_door-1.jpg"), "/clips/front_door-1.jpg"
+        )
+
+    def test_repeated_slashes_merged(self):
+        self.assertEqual(
+            extract_path("/recordings//2026-05-11/14//front_door/00.00.mp4"),
+            "/recordings/2026-05-11/14/front_door/00.00.mp4",
+        )
+        self.assertEqual(
+            extract_path("/%2Fclips/front_door-1.jpg"), "/clips/front_door-1.jpg"
+        )
+
 
 class TestResolveMediaUri(unittest.TestCase):
     def setUp(self):
@@ -376,6 +390,34 @@ class TestDenyResponseForMediaUri(unittest.TestCase):
         self.assertIsNone(self._deny("/clips/nonexistent-1.jpg", "admin"))
         self.assertIsNone(self._deny("/clips/nonexistent-1.jpg", "viewer"))
 
+    def test_repeated_slashes_resolve_to_owning_camera(self):
+        # nginx merges repeated slashes before matching the media locations
+        for url in (
+            "//clips/back_door-1.jpg",
+            "/clips//back_door-1.jpg",
+            "//recordings/2026-05-11/14/back_door/00.00.mp4",
+            "/recordings//2026-05-11/14/back_door/00.00.mp4",
+        ):
+            self.assertEqual(self._deny(url, "limited_user"), 403, url)
+        self.assertIsNone(self._deny("//clips/front_door-1.jpg", "limited_user"))
+
+    def test_traversal_with_leading_double_slash_denied(self):
+        self.assertEqual(
+            self._deny("//clips/front_door/../back_door-1.jpg", "admin"), 403
+        )
+
+    def test_traversal_from_non_media_prefix_denied(self):
+        # nginx resolves these into a media root before serving
+        for url in (
+            "/x/../clips/back_door-1.jpg",
+            "/x/%2E%2E/clips/back_door-1.jpg",
+            "/./clips/front_door/../back_door-1.jpg",
+            "/api/../recordings/2026-05-11/14/back_door/00.00.mp4",
+            "/clips/back_door-1.jpg#/../../x",
+        ):
+            self.assertEqual(self._deny(url, "limited_user"), 403, url)
+        self.assertIsNone(self._deny("/x/../api/events", "limited_user"))
+
 
 if __name__ == "__main__":
     unittest.main()