The SSRF blocklist had no escape hatch, so the thing webhooker is
mostly for — taking a public webhook and forwarding it to something
on your own network — could not be configured at all. Every private
address, Docker sibling and loopback service was permanently
unreachable as a delivery destination.
ALLOWED_EGRESS_CIDRS (default empty) names blocks that delivery
targets may reach despite the default blocklist. It is an allowlist
and only ever adds destinations: there is no boolean, and no value
disables SSRF protection wholesale. Empty, the guard behaves exactly
as before.
Link-local (169.254.0.0/16, fe80::/10) is refused before the
allowlist is consulted, so no supplied CIDR can open it — not the
exact address, not a supernet, not 0.0.0.0/0. Reaching cloud
instance metadata is credential theft rather than delivery to an
internal service.
The policy now lives in one function, Guard.checkIP, which both
target-creation validation and the delivery dialer call. The two
paths previously decided separately, which is how they came to
disagree about a destination. The guard is built once from config
and injected via fx into both the handlers and the delivery engine,
so there is a single instance and a single answer.
A set-but-unparseable value aborts startup naming the variable,
reusing the existing envPrefixList parser. A non-empty list is
logged at startup with the blocks spelled out, not counted, so the
hole is visible in the log of any deployment that has one.
Tests: an allowlisted loopback CIDR both validates and delivers to a
live server (and the same URL still fails without the allowlist); a
private address outside the listed block stays refused on both
paths; metadata stays refused under six different covering CIDRs;
public addresses are unaffected either way; and config coverage for
parsing, startup abort, and the warning's contents.
check / check (push) Superseded by a newer commit; never tested
`clientForConfig()` in `internal/delivery/engine.go` built a fresh `http.Client` without a Transport when a per-target timeout was configured, dropping the request-time private-IP guard for that path.
It now reuses the shared client's SSRF-safe transport (`e.client.Transport`, the same `NewSSRFSafeTransport` instance), overriding only the `Timeout`. Behaviour is unchanged when no per-target timeout is set (the shared client is returned as before), so no engine code path makes an outbound target request with a client lacking the SSRF-safe transport.
Adds a delivery-package test proving a client from `clientForConfig()` with a per-target timeout still refuses private/reserved/link-local destinations, that the timeout is applied, that the SSRF-safe transport is reused (not duplicated), and that the no-timeout path returns the shared client unchanged.
Confined to `internal/delivery/` only; handlers and server code untouched.
Closes#69
Co-authored-by: sneak <sneak@sneak.berlin>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #74
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
