File size: 4,791 Bytes
2b9a95b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | """
Admin-endpoint access control.
Every request to /api/admin/* must present an X-Admin-Token header whose value
matches the ADMIN_TOKEN environment variable. The token is bootstrapped at
application startup: if .env does not contain ADMIN_TOKEN, one is generated
deterministically from the current UTC time (SHA-256 hexdigest) and appended
to the .env file, and the value is loaded into os.environ for the running
process.
Why the token exists:
OpenCode agent containers share a docker network with the backend, so any
unauthenticated /api/admin/* route (test-deploy, status, scm_model, ...)
is directly reachable and has been observed to be exploited as a
budget-bypass oracle. Gating the router closes that surface.
"""
from __future__ import annotations
import hashlib
import logging
import os
import secrets
from datetime import datetime, timezone
from pathlib import Path
from typing import Optional
from fastapi import Header, HTTPException, status
logger = logging.getLogger(__name__)
ADMIN_TOKEN_VAR = "ADMIN_TOKEN"
def _find_repo_root() -> Path:
"""Return the directory that should host .env (the repo root)."""
# api/security.py -> api/ -> repo root
return Path(__file__).resolve().parent.parent
def _generate_token() -> str:
"""
SHA-256 hex digest of (current UTC time as ISO-8601 + 32 random bytes).
The random suffix ensures uniqueness even if two processes call this
within the same wall-clock second. The timestamp is included so a
human reading the .env can see roughly when the token was minted.
"""
ts = datetime.now(timezone.utc).isoformat(timespec="microseconds")
entropy = secrets.token_hex(32)
return hashlib.sha256(f"{ts}|{entropy}".encode("utf-8")).hexdigest()
def _append_to_env_file(env_path: Path, key: str, value: str) -> None:
"""Append `KEY=value` to `.env`, preceded by a blank line if the file is non-empty."""
prefix = ""
if env_path.exists() and env_path.stat().st_size > 0:
# Ensure we start on a fresh line.
with env_path.open("rb") as f:
f.seek(-1, os.SEEK_END)
last = f.read(1)
if last not in (b"\n", b""):
prefix = "\n"
with env_path.open("a", encoding="utf-8") as f:
f.write(
f"{prefix}\n# Auto-generated by api/security.py on "
f"{datetime.now(timezone.utc).isoformat(timespec='seconds')}.\n"
f"# Rotate by deleting this line and restarting the backend.\n"
f"{key}={value}\n"
)
def ensure_admin_token_in_env() -> str:
"""
Guarantee that os.environ[ADMIN_TOKEN] is set.
Order of resolution:
1. If os.environ already has ADMIN_TOKEN → keep it.
2. Else generate a fresh token, append it to <repo>/.env, and export
it into os.environ so subsequent requests can validate against it.
Returns the token value (for convenience — callers should not need it).
"""
existing = os.environ.get(ADMIN_TOKEN_VAR)
if existing:
return existing
token = _generate_token()
env_path = _find_repo_root() / ".env"
try:
_append_to_env_file(env_path, ADMIN_TOKEN_VAR, token)
logger.info(
"Bootstrapped %s and appended it to %s (fingerprint=%s...)",
ADMIN_TOKEN_VAR,
env_path,
token[:8],
)
except OSError as e:
# Read-only filesystem etc. — still export to os.environ so the
# running process can operate; operator will need to persist manually.
logger.warning(
"Could not write %s to %s (%s); token exists only for this process.",
ADMIN_TOKEN_VAR,
env_path,
e,
)
os.environ[ADMIN_TOKEN_VAR] = token
return token
async def require_admin_token(
x_admin_token: Optional[str] = Header(None, alias="X-Admin-Token"),
) -> None:
"""
FastAPI dependency: reject the request unless X-Admin-Token matches
the ADMIN_TOKEN environment variable.
Applied at router level (see api/admin/endpoints.py) so every /api/admin/*
route inherits the check without per-endpoint boilerplate.
"""
expected = os.environ.get(ADMIN_TOKEN_VAR)
if not expected:
# ensure_admin_token_in_env() should have set this at startup; if we
# reach here, the operator has misconfigured the deployment.
raise HTTPException(
status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
detail="Admin token not initialized on server.",
)
if not x_admin_token or not secrets.compare_digest(x_admin_token, expected):
raise HTTPException(
status_code=status.HTTP_403_FORBIDDEN,
detail="Missing or invalid X-Admin-Token header.",
)
|