### What problem does this PR solve?
Closes#14858
The `test_db_connection` endpoint in the agent API accepts a
user-supplied `host` and connects to it directly via database drivers
(MySQL/PostgreSQL) without any validation. This allows an attacker to
probe internal network addresses (e.g. `127.0.0.1`, `10.x.x.x`,
link-local, etc.) through the server — a classic Server-Side Request
Forgery (SSRF) vulnerability.
This PR adds an SSRF guard that resolves the host and rejects any
address that is not globally routable before the database connection is
attempted.
**Changes:**
- **`common/ssrf_guard.py`** — Added `assert_host_is_safe()`, a
host-level counterpart of the existing `assert_url_is_safe()`, designed
for non-HTTP protocols (database drivers) where there is no URL to
parse.
- **`api/apps/restful_apis/agent_api.py`** — Call
`assert_host_is_safe(req["host"])` at the top of `test_db_connection` so
that non-public hosts are rejected early with a clear error message.
Fixes#14858
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
---------
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
The POST /upload_info?url=<url> endpoint accepted a user-supplied URL
and passed it directly to AsyncWebCrawler without any validation. There
were no restrictions on URL scheme, destination hostname, or resolved IP
address. This allowed any authenticated user to instruct the server to
make outbound HTTP requests to internal infrastructure — including RFC
1918 private networks, loopback addresses, and cloud metadata services
such as http://169.254.169.254 — effectively using the server as a proxy
for internal network reconnaissance or credential theft.
This PR adds an SSRF guard (_validate_url_for_crawl) that runs before
any crawl is initiated. It enforces an allowlist of safe schemes
(http/https), resolves the hostname at validation time, and rejects any
URL whose resolved IP falls within a private or reserved network range.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
