HTTP/HTTPS uptime monitors targeting LAN addresses (192.168.x.x,
10.x.x.x, 172.16.x.x) permanently reported 'down' on fresh installs
because SSRF protection rejects RFC 1918 ranges at two independent
checkpoints: the URL validator (DNS-resolution layer) and the safe
dialer (TCP-connect layer). Fixing only one layer leaves the monitor
broken in practice.
- Add IsRFC1918() predicate to the network package covering only the
three RFC 1918 CIDRs; 169.254.x.x (link-local / cloud metadata)
and loopback are intentionally excluded
- Add WithAllowRFC1918() functional option to both SafeHTTPClient and
ValidationConfig; option defaults to false so existing behaviour is
unchanged for every call site except uptime monitors
- In uptime_service.go, pass WithAllowRFC1918() to both
ValidateExternalURL and NewSafeHTTPClient together; a coordinating
comment documents that both layers must be relaxed as a unit
- 169.254.169.254 and the full 169.254.0.0/16 link-local range remain
unconditionally blocked; the cloud-metadata error path is preserved
- 21 new tests across three packages, including an explicit regression
guard that confirms RFC 1918 blocks are still applied without the
option set (TestValidateExternalURL_RFC1918BlockedByDefault)
Fixes issues 6 and 7 from the fresh-install bug report.
00a18704e8