sanitize user-supplied path components (#23990)

sanitize_filename leaves ".." intact and collapses variants like "..:" and "..*" to "..", so filesystem paths built from face names, classification model/category names, image ids, and trigger data could escape their base directory. Route every such site through new frigate/util/path.py helpers (safe_join, sanitize_path_component, sanitize_contained_path), which reject traversal and verify containment.

Worst case was DELETE /classification/{name}, which rmtree'd /media/frigate and /config while returning 200.

Important to note that all affected endpoints already require admin permission, so this sould be considered hardening rather than fixing exploitable code.

frigate/api/event.py

@@ -16,7 +16,6 @@ import numpy as np
 from fastapi import APIRouter, Request
 from fastapi.params import Depends
 from fastapi.responses import JSONResponse
-from pathvalidate import sanitize_filename
 from peewee import JOIN, DoesNotExist, fn, operator
 from playhouse.shortcuts import model_to_dict
 
@@ -56,11 +55,12 @@ from frigate.api.defs.response.generic_response import GenericResponse
 from frigate.api.defs.tags import Tags
 from frigate.comms.event_metadata_updater import EventMetadataTypeEnum
 from frigate.config.classification import ObjectClassificationType
-from frigate.const import CLIPS_DIR, TRIGGER_DIR
+from frigate.const import CLIPS_DIR
 from frigate.embeddings import EmbeddingsContext
 from frigate.models import Event, ReviewSegment, Timeline, Trigger
 from frigate.track.object_processing import TrackedObject
 from frigate.util.file import get_event_thumbnail_bytes, load_event_snapshot_image
+from frigate.util.path import get_trigger_thumbnail_path, safe_join
 from frigate.util.time import get_dst_transitions, get_tz_modifiers
 
 logger = logging.getLogger(__name__)
@@ -1452,10 +1452,10 @@ async def set_attributes(
             continue
 
         # Get available labels from dataset directory
-        dataset_dir = os.path.join(CLIPS_DIR, sanitize_filename(model_key), "dataset")
+        dataset_dir = safe_join(CLIPS_DIR, model_key, "dataset")
         available_labels = set()
 
-        if os.path.exists(dataset_dir):
+        if dataset_dir and os.path.exists(dataset_dir):
             for category_name in os.listdir(dataset_dir):
                 category_dir = os.path.join(dataset_dir, category_name)
                 if os.path.isdir(category_dir):
@@ -1959,18 +1959,13 @@ def create_trigger_embedding(
         if body.type == "thumbnail":
             # Save image to the triggers directory
             try:
-                os.makedirs(
-                    os.path.join(TRIGGER_DIR, sanitize_filename(camera_name)),
-                    exist_ok=True,
-                )
-                with open(
-                    os.path.join(
-                        TRIGGER_DIR,
-                        sanitize_filename(camera_name),
-                        f"{sanitize_filename(body.data)}.webp",
-                    ),
-                    "wb",
-                ) as f:
+                webp_path = get_trigger_thumbnail_path(camera_name, body.data)
+
+                if webp_path is None:
+                    raise ValueError(f"Invalid trigger thumbnail path for {body.data}")
+
+                os.makedirs(os.path.dirname(webp_path), exist_ok=True)
+                with open(webp_path, "wb") as f:
                     f.write(thumbnail)
                 logger.debug(
                     f"Writing thumbnail for trigger with data {body.data} in {camera_name}."
@@ -2042,10 +2037,16 @@ def update_trigger_embedding(
         if body.type == "description":
             embedding = context.generate_description_embedding(body.data)
         elif body.type == "thumbnail":
-            webp_file = sanitize_filename(body.data) + ".webp"
-            webp_path = os.path.join(
-                TRIGGER_DIR, sanitize_filename(camera_name), webp_file
-            )
+            webp_path = get_trigger_thumbnail_path(camera_name, body.data)
+
+            if webp_path is None:
+                return JSONResponse(
+                    content={
+                        "success": False,
+                        "message": f"Invalid data for {body.type} trigger",
+                    },
+                    status_code=400,
+                )
 
             try:
                 event: Event = Event.get(Event.id == body.data)
@@ -2102,13 +2103,14 @@ def update_trigger_embedding(
             # Update existing trigger
             if trigger.data != body.data:  # Delete old thumbnail only if data changes
                 try:
-                    os.remove(
-                        os.path.join(
-                            TRIGGER_DIR,
-                            sanitize_filename(camera_name),
-                            f"{trigger.data}.webp",
+                    old_path = get_trigger_thumbnail_path(camera_name, trigger.data)
+
+                    if old_path is None:
+                        raise ValueError(
+                            f"Invalid trigger thumbnail path for {trigger.data}"
                         )
-                    )
+
+                    os.remove(old_path)
                     logger.debug(
                         f"Deleted thumbnail for trigger with data {trigger.data} in {camera_name}."
                     )
@@ -2142,12 +2144,13 @@ def update_trigger_embedding(
         if body.type == "thumbnail":
             # Save image to the triggers directory
             try:
-                camera_path = os.path.join(TRIGGER_DIR, sanitize_filename(camera_name))
-                os.makedirs(camera_path, exist_ok=True)
-                with open(
-                    os.path.join(camera_path, f"{sanitize_filename(body.data)}.webp"),
-                    "wb",
-                ) as f:
+                thumbnail_path = get_trigger_thumbnail_path(camera_name, body.data)
+
+                if thumbnail_path is None:
+                    raise ValueError(f"Invalid trigger thumbnail path for {body.data}")
+
+                os.makedirs(os.path.dirname(thumbnail_path), exist_ok=True)
+                with open(thumbnail_path, "wb") as f:
                     f.write(thumbnail)
                 logger.debug(
                     f"Writing thumbnail for trigger with data {body.data} in {camera_name}."
@@ -2218,11 +2221,12 @@ def delete_trigger_embedding(
             )
 
         try:
-            os.remove(
-                os.path.join(
-                    TRIGGER_DIR, sanitize_filename(camera_name), f"{trigger.data}.webp"
-                )
-            )
+            thumbnail_path = get_trigger_thumbnail_path(camera_name, trigger.data)
+
+            if thumbnail_path is None:
+                raise ValueError(f"Invalid trigger thumbnail path for {trigger.data}")
+
+            os.remove(thumbnail_path)
             logger.debug(
                 f"Deleted thumbnail for trigger with data {trigger.data} in {camera_name}."
             )