Files
homelable/backend/app/api/routes/media.py
T
Pouzor 2d376c2bed fix: harden media path handling against path injection (CodeQL py/path-injection)
Resolve media filenames through a shared _resolve_media_path() barrier that
confirms the resolved path sits directly under the resolved media dir, so
CodeQL can trace the sanitization the regex already guaranteed.

ha-relevant: no
2026-07-07 11:50:12 +02:00

103 lines
3.7 KiB
Python

"""Generic media upload/serve endpoint.
Images are stored on disk (see `Settings.media_dir`) with server-generated
UUID filenames — never in the DB, and the client filename is never trusted.
Upload/delete require auth; GET is public so plain <img> tags and the read-only
live view can load images (filenames are unguessable).
Currently used by the floor-plan feature; kept deliberately generic so future
raw-image uploads reuse the same endpoint.
"""
import re
import uuid
from pathlib import Path
from fastapi import APIRouter, Depends, HTTPException, UploadFile, status
from fastapi.responses import FileResponse
from app.api.deps import get_current_user
from app.core.config import settings
router = APIRouter()
# content-type → extension. Also the allowlist of accepted uploads.
ALLOWED_TYPES: dict[str, str] = {
"image/png": ".png",
"image/jpeg": ".jpg",
"image/webp": ".webp",
}
# Magic-byte signatures for defense-in-depth (don't trust content-type alone).
_MAGIC: dict[str, tuple[bytes, ...]] = {
".png": (b"\x89PNG\r\n\x1a\n",),
".jpg": (b"\xff\xd8\xff",),
".webp": (b"RIFF",), # RIFF....WEBP; RIFF prefix is enough to reject non-images
}
MAX_BYTES = 10 * 1024 * 1024 # 10 MB
# Only ever serve/delete files we created: 32 hex chars + known extension.
_NAME_RE = re.compile(r"^[0-9a-f]{32}\.(png|jpg|webp)$")
def _resolve_media_path(filename: str) -> Path:
"""Resolve `filename` inside the media dir, rejecting anything that escapes it.
`filename` is validated against `_NAME_RE` (no separators, no `..`) and the
resolved path is confirmed to sit directly under the resolved media dir.
Raises 404 on any mismatch so we never leak whether a path exists elsewhere.
"""
if not _NAME_RE.match(filename):
raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Not found")
base = settings.media_dir().resolve()
path = (base / filename).resolve()
if path.parent != base:
raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Not found")
return path
@router.post("/upload")
async def upload_media(file: UploadFile, _user: str = Depends(get_current_user)) -> dict[str, str]:
ext = ALLOWED_TYPES.get(file.content_type or "")
if ext is None:
raise HTTPException(
status_code=status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
detail="Unsupported media type — PNG, JPEG, or WebP only",
)
# Read one byte past the cap so we can detect oversize without loading more.
data = await file.read(MAX_BYTES + 1)
if len(data) > MAX_BYTES:
raise HTTPException(
status_code=status.HTTP_413_CONTENT_TOO_LARGE,
detail="File too large (max 10 MB)",
)
if not data:
raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Empty file")
if not any(data.startswith(sig) for sig in _MAGIC[ext]):
raise HTTPException(
status_code=status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
detail="File content does not match its type",
)
media_dir = settings.media_dir()
media_dir.mkdir(parents=True, exist_ok=True)
name = f"{uuid.uuid4().hex}{ext}"
(media_dir / name).write_bytes(data)
return {"filename": name, "url": f"/api/v1/media/{name}"}
@router.get("/{filename}")
async def get_media(filename: str) -> FileResponse:
path = _resolve_media_path(filename)
if not path.is_file():
raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Not found")
return FileResponse(path)
@router.delete("/{filename}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_media(filename: str, _user: str = Depends(get_current_user)) -> None:
path = _resolve_media_path(filename)
if path.is_file():
path.unlink()