Description:
Before this change, Envoy would silently ignore the `x-envoy-*` header if a
client specifies an invalid value for this header (e.g. `x-envoy-max-retries: 3.0`).
Introduce a `strict_check_headers` config option for `envoy.router` that adds
optional support to reject requests with invalid values for the following headers:
- x-envoy-upstream-rq-timeout-ms
- x-envoy-upstream-rq-per-try-timeout-ms
- x-envoy-max-retries
- x-envoy-retry-on
- x-envoy-retry-grpc-on
On rejection, Envoy responds with HTTP status 400 and sets a new response flag
`IH` to indicate the reason was due to an invalid header.
Risk Level: Low/medium
Testing: unit tests
- unit test: `FilterUtility::StrictHeaderChecker`
- test that router rejects request with HTTP status 400 + setting the `IH` response flag
- test that config validation rejects unsupported values
- manual end-to-end test `client -> envoy -> upstream server` to verify that
Envoy returns a 400 and sets the response flag in the logs
Docs Changes:
- add inline docs to `router.proto` for `strict_check_headers`
- add inline docs to `accesslog.proto` for `IH` response flag
Release Notes: updated for router and accesslog
Fixes#6482
Signed-off-by: Xiao Yu <xyu@stripe.com>
Mirrored from https://github.com/envoyproxy/envoy @ ecd03a4eed07e1cfea9e9844e519b7fffada437a