浅念
7b26c7e14a
- _utf8_ok 助手：event_id/path/title 含孤代理（"\ud800"）在入口即拒 （原会流到下游 encode 必 500）；props 字节守门 try/except 归入 properties_invalid - 补零覆盖原因码测试：path=123 → invalid_field_type；utm 三层嵌套 → properties_depth - 子串断言（"sensitive" in r 等）全改精确等值断言，码即 API - path 改为先 sanitize_url 再截 500：中文查询参数 urlencode 膨胀最多 3 倍， 先截后洗会破坏出门 ≤MAX_PATH_LEN 不变量（实测汉*200 查询洗后截回 500） - docstring 写明就地写回契约（Task 6 ingest 依赖） Co-Authored-By: Claude Code <noreply@anthropic.com>
106 lines
4.6 KiB
Python
106 lines
4.6 KiB
Python
import json
|
||
import re
|
||
from datetime import datetime
|
||
from urllib.parse import parse_qsl, urlencode, urlparse
|
||
from django.utils import timezone
|
||
from tracker import constants as C
|
||
|
||
_SENSITIVE = re.compile("|".join(C.SENSITIVE_KEY_PATTERNS), re.I)
|
||
_URL_DROP_KEY = re.compile("|".join(C.URL_PARAM_DROP_PATTERNS), re.I)
|
||
|
||
def _utf8_ok(s: str) -> bool:
|
||
"""孤代理（如 "\ud800"）在下游 encode/JSON 序列化时必然 500，入口处即拒。"""
|
||
try:
|
||
s.encode("utf-8")
|
||
return True
|
||
except UnicodeEncodeError:
|
||
return False
|
||
|
||
def sanitize_url(url: str) -> str:
|
||
"""按参数名整键删除（fullmatch 防止误伤 monkey 这类含 key 子串的参数）。"""
|
||
p = urlparse(url)
|
||
kept = [(k, v) for k, v in parse_qsl(p.query, keep_blank_values=True)
|
||
if not _URL_DROP_KEY.fullmatch(k)]
|
||
return p._replace(query=urlencode(kept)).geturl()
|
||
|
||
def _walk_props(v, depth=0):
|
||
"""单次递归同时做深度检查、敏感键扫描与字符串超长检查。
|
||
dict 所有层级的键都过 _SENSITIVE，所有层级的字符串都受 MAX_STR_LEN 约束。
|
||
返回 (depth_ok, sensitive_hit, str_too_long)。深度超限即停止下探，防恶意深嵌套递归爆栈。"""
|
||
if depth > C.MAX_PROP_DEPTH:
|
||
return False, False, False
|
||
if isinstance(v, dict):
|
||
depth_ok, sens, too_long = True, False, False
|
||
for k, x in v.items():
|
||
if _SENSITIVE.search(str(k)):
|
||
sens = True
|
||
d, s, l = _walk_props(x, depth + 1)
|
||
depth_ok = depth_ok and d
|
||
sens = sens or s
|
||
too_long = too_long or l
|
||
return depth_ok, sens, too_long
|
||
if isinstance(v, list):
|
||
depth_ok, sens, too_long = True, False, False
|
||
for x in v:
|
||
d, s, l = _walk_props(x, depth + 1)
|
||
depth_ok = depth_ok and d
|
||
sens = sens or s
|
||
too_long = too_long or l
|
||
return depth_ok, sens, too_long
|
||
if isinstance(v, str) and len(v) > C.MAX_STR_LEN:
|
||
return True, False, True
|
||
return True, False, False
|
||
|
||
def validate_event(ev) -> str | None:
|
||
"""返回 None 表示通过；否则返回拒绝原因码。类型/白名单/体积/深度全在此守门。
|
||
通过时会就地截断/清洗并写回 ev（path 先 sanitize_url 再截 MAX_PATH_LEN，title 截
|
||
MAX_TITLE_LEN）——Task 6 的 ingest 依赖此写回契约。"""
|
||
if not isinstance(ev, dict):
|
||
return "event_invalid_shape"
|
||
if ev.get("event_name") not in C.EVENT_NAMES:
|
||
return "event_name_not_allowed"
|
||
eid = ev.get("event_id")
|
||
if not isinstance(eid, str) or not eid or len(eid) > 64 or not _utf8_ok(eid):
|
||
return "invalid_event_id"
|
||
for k in ("path", "title"):
|
||
v = ev.get(k)
|
||
if v is not None and (not isinstance(v, str) or not _utf8_ok(v)):
|
||
return "invalid_field_type"
|
||
occ = ev.get("occurred_at")
|
||
if not isinstance(occ, datetime):
|
||
return "invalid_occurred_at"
|
||
if timezone.is_naive(occ):
|
||
return "invalid_occurred_at"
|
||
skew = (timezone.now() - occ).total_seconds()
|
||
if abs(skew) > C.CLOCK_SKEW_REJECT_SEC:
|
||
return "occurred_at_out_of_window"
|
||
props = ev.get("properties", {})
|
||
if not isinstance(props, dict) or len(props) > C.MAX_PROP_KEYS:
|
||
return "properties_invalid" # 传了但非 dict（[]/""/0/None）一律拒
|
||
# 敏感键扫描（含嵌套层级）先于属性白名单：白名单内无任何键命中敏感模式，
|
||
# 若放在白名单之后，sensitive_field 将不可达（见 test_sensitive_property_rejected）。
|
||
depth_ok, sensitive_hit, str_too_long = _walk_props(props)
|
||
if sensitive_hit:
|
||
return "sensitive_field"
|
||
if not set(props) <= C.EVENT_PROP_WHITELIST.get(ev["event_name"], set()):
|
||
return "property_not_allowed"
|
||
if not depth_ok:
|
||
return "properties_depth"
|
||
# 体积按 UTF-8 字节数守门（汉字多字节，按字符数会被绕过）；孤代理 encode 必炸，按 invalid 拒
|
||
try:
|
||
prop_bytes = len(json.dumps(props, ensure_ascii=False, default=str).encode("utf-8"))
|
||
except UnicodeEncodeError:
|
||
return "properties_invalid"
|
||
if prop_bytes > C.MAX_PROP_JSON_BYTES:
|
||
return "properties_too_large"
|
||
if str_too_long:
|
||
return "properties_too_long"
|
||
# 先清洗后截断：urlencode 对中文查询参数最多膨胀 3 倍，先截后洗会破坏"出门 ≤MAX_PATH_LEN"不变量
|
||
if ev.get("path"):
|
||
ev["path"] = sanitize_url(ev["path"])
|
||
if len(ev.get("path") or "") > C.MAX_PATH_LEN:
|
||
ev["path"] = ev["path"][:C.MAX_PATH_LEN]
|
||
if len(ev.get("title") or "") > C.MAX_TITLE_LEN:
|
||
ev["title"] = ev["title"][:C.MAX_TITLE_LEN]
|
||
return None
|