fix(security): close remaining SSRF (CWE-918) call sites via shared URL validator

[Copilot]

PR #6455 fixed SSRF in application.py by replacing startswith() prefix checks with proper urlparse-based validation, but left 6 identical vulnerable call sites unpatched across tools/serializers/tool.py, tools/serializers/tool_workflow.py, and knowledge/serializers/knowledge_workflow.py.

Changes

New shared utility: apps/common/utils/url_validator.py

• validate_trusted_url(url, allowed_hosts) — urlparse-based validator: requires https scheme, exact hostname allowlist match, rejects userinfo (user:pass@host) and explicit ports
• ALLOWED_DOWNLOAD_HOSTS = {"apps-assets.fit2cloud.com"}
• ALLOWED_CALLBACK_HOSTS = {"apps.fit2cloud.com"}

apps/application/serializers/application.py

• Replaced local _validate_trusted_url / _ALLOWED_* definitions with imports from the shared module (behavior unchanged)

apps/tools/serializers/tool.py

• Replaced startswith() in Create.insert, AddStoreTool.add, and UpdateStoreTool.update_tool (download + callback)
• UpdateStoreTool.update_tool's callback requests.get was completely unguarded — added validate_trusted_url check and allow_redirects=False

apps/tools/serializers/tool_workflow.py and apps/knowledge/serializers/knowledge_workflow.py

• Replaced all startswith() checks with validate_trusted_url; added allow_redirects=False to all affected requests.get calls

Before / After

# Before — bypassable via https://apps-assets.fit2cloud.com@attacker.com/
if not download_url.startswith("https://apps-assets.fit2cloud.com/"):
    raise AppApiException(500, _("Illegal download url"))
res = requests.get(download_url, timeout=5)

# After
if not validate_trusted_url(download_url, ALLOWED_DOWNLOAD_HOSTS):
    raise AppApiException(500, _("Illegal download url"))
res = requests.get(download_url, timeout=5, allow_redirects=False)

The pickle deserialization sink in tool.py (RestrictedUnpickler(...).load()) is fed from the download response, making the unpatched call sites particularly high severity.

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[shaohuzhang1]

Seems you are using me but didn't get OPENAI_API_KEY seted in Variables/Secrets for this repo. you could follow readme for more information