Adds JWT Authn User Docs (#991)

Signed-off-by: danehans <daneyonhansen@gmail.com>

docs/latest/dev/README.md

@@ -126,6 +126,14 @@ Now you are able to view the running Envoy configuration by navigating to `127.0
 
 There are many other endpoints on the [Envoy admin interface][] that may be helpful when debugging.
 
+### JWT Testing
+
+An example [JSON Web Token (JWT)][jwt] and [JSON Web Key Set (JWKS)][jwks] are used for the [request authentication][]
+user guide. The JWT was created by the [JWT Debugger][], using the `RS256` algorithm. The public key from the JWTs
+verify signature was copied to [JWK Creator][] for generating the JWK. The JWK Creator was configured with matching
+settings, i.e. `Signing` public key use and the `RS256` algorithm. The generated JWK was wrapped in a JWKS structure
+and is hosted in the repo.
+
 [Quickstart]: https://github.com/envoyproxy/gateway/blob/main/docs/user/quickstart.md
 [make]: https://www.gnu.org/software/make/
 [Github Actions]: https://docs.github.com/en/actions
@@ -137,3 +145,8 @@ There are many other endpoints on the [Envoy admin interface][] that may be help
 [gateway-dev]: https://hub.docker.com/r/envoyproxy/gateway-dev/tags
 [mac_connect]: https://github.com/chipmk/docker-mac-net-connect
 [Envoy admin interface]: https://www.envoyproxy.io/docs/envoy/latest/operations/admin#operations-admin-interface
+[jwt]: https://tools.ietf.org/html/rfc7519
+[jwks]: https://tools.ietf.org/html/rfc7517
+[request authentication]: https://gateway.envoyproxy.io/latest/user/authn.html
+[JWT Debugger]: https://jwt.io/
+[JWK Creator]: https://russelldavies.github.io/jwk-creator/

docs/latest/user/authn.md

@@ -0,0 +1,94 @@
+# Request Authentication
+
+This guide provides instructions for configuring [JSON Web Token (JWT)][jwt] authentication. JWT authentication checks
+if an incoming request has a valid JWT before routing the request to a backend service. Currently, Envoy Gateway only
+supports validating a JWT from an HTTP header, e.g. `Authorization: Bearer <token>`.
+
+## Installation
+
+Follow the steps from the [Quickstart](quickstart.md) guide to install Envoy Gateway and the example manifest.
+Before proceeding, you should be able to query the example backend using HTTP.
+
+## Configuration
+
+Allow requests with a valid JWT by creating an [AuthenticationFilter][] and referencing it from the example HTTPRoute.
+
+```shell
+kubectl apply -f https://raw.githubusercontent.com/envoyproxy/gateway/latest/examples/kubernetes/authn/jwt.yaml
+```
+
+The HTTPRoute is now updated to authenticate requests for `/foo` and allow unauthenticated requests to `/bar`. The
+`/foo` route rule references an AuthenticationFilter that provides the JWT authentication configuration.
+
+Verify the HTTPRoute configuration and status:
+
+```shell
+kubectl get httproute/backend -o yaml
+```
+
+The AuthenticationFilter is configured for JWT authentication and uses a single [JSON Web Key Set (JWKS)][jwks]
+provider for authenticating the JWT.
+
+Verify the AuthenticationFilter configuration:
+
+```shell
+kubectl get authenticationfilter/jwt-example -o yaml
+```
+
+## Testing
+
+Ensure the `GATEWAY_HOST` environment variable from the [Quickstart](quickstart.md) guide is set. If not, follow the
+Quickstart instructions to set the variable.
+
+```shell
+echo $GATEWAY_HOST
+```
+
+Verify that requests to `/foo` are denied without a JWT:
+
+```shell
+curl -sS -o /dev/null -H "Host: www.example.com" -w "%{http_code}\n" http://$GATEWAY_HOST/foo
+```
+
+A `401` HTTP response code should be returned.
+
+Get the JWT used for testing request authentication:
+
+```shell
+TOKEN=$(curl https://raw.githubusercontent.com/envoyproxy/gateway/main/examples/kubernetes/authn/test.jwt -s) && echo "$TOKEN" | cut -d '.' -f2 - | base64 --decode -
+```
+
+__Note:__ The above command decodes and returns the token's payload. You can replace `f2` with `f1` to view the token's
+header.
+
+Verify that a request to `/foo` with a valid JWT is allowed:
+
+```shell
+curl -sS -o /dev/null -H "Host: www.example.com" -H "Authorization: Bearer $TOKEN" -w "%{http_code}\n" http://$GATEWAY_HOST/foo
+```
+
+A `200` HTTP response code should be returned.
+
+Verify that requests to `/bar` are allowed __without__ a JWT:
+
+```shell
+curl -sS -o /dev/null -H "Host: www.example.com" -w "%{http_code}\n" http://$GATEWAY_HOST/bar
+```
+
+## Clean-Up
+
+Follow the steps from the [Quickstart](quickstart.md) guide to uninstall Envoy Gateway and the example manifest.
+
+Delete the AuthenticationFilter:
+
+```shell
+kubectl delete authenticationfilter/jwt-example
+```
+
+## Next Steps
+
+Checkout the [Developer Guide](../dev/README.md) to get involved in the project.
+
+[jwt]: https://tools.ietf.org/html/rfc7519
+[AuthenticationFilter]: https://github.com/envoyproxy/gateway/blob/main/api/v1alpha1/authenticationfilter_types.go
+[jwks]: https://tools.ietf.org/html/rfc7517

docs/latest/user_docs.rst

@@ -18,3 +18,4 @@ Learn how to deploy, use, and operate Envoy Gateway.
   user/tcp-routing
   user/udp-routing
   user/grpc-routing
+  user/authn

examples/kubernetes/authn/jwks.json

@@ -0,0 +1 @@
+{"keys":[{"kty":"RSA","n":"u1SU1LfVLPHCozMxH2Mo4lgOEePzNm0tRgeLezV6ffAt0gunVTLw7onLRnrq0_IzW7yWR7QkrmBL7jTKEn5u-qKhbwKfBstIs-bMY2Zkp18gnTxKLxoS2tFczGkPLPgizskuemMghRniWaoLcyehkd3qqGElvW_VDL5AaWTg0nLVkjRo9z-40RQzuVaE8AkAFmxZzow3x-VJYKdjykkJ0iT9wCS0DRTXu269V264Vf_3jvredZiKRkgwlL9xNAwxXFg0x_XFw005UWVRIkdgcKWTjpBP2dPwVZ4WWC-9aGVd-Gyn1o0CLelf4rEjGoXbAAEgAqeGUxrcIlbjXfbcmw","e":"AQAB","alg":"RS256","use":"sig"}]}

examples/kubernetes/authn/jwt.yaml

@@ -0,0 +1,47 @@
+apiVersion: gateway.envoyproxy.io/v1alpha1
+kind: AuthenticationFilter
+metadata:
+  name: jwt-example
+spec:
+  type: JWT
+  jwtProviders:
+  - name: example
+    remoteJWKS:
+      uri: https://raw.githubusercontent.com/envoyproxy/gateway/main/examples/kubernetes/authn/jwks.json
+---
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+  name: backend
+spec:
+  parentRefs:
+  - name: eg
+  hostnames:
+  - "www.example.com"
+  rules:
+  - backendRefs:
+    - group: ""
+      kind: Service
+      name: backend
+      port: 3000
+      weight: 1
+    filters:
+    - extensionRef:
+        group: gateway.envoyproxy.io
+        kind: AuthenticationFilter
+        name: jwt-example
+      type: ExtensionRef
+    matches:
+    - path:
+        type: PathPrefix
+        value: /foo
+  - backendRefs:
+    - group: ""
+      kind: Service
+      name: backend
+      port: 3000
+      weight: 1
+    matches:
+    - path:
+        type: PathPrefix
+        value: /bar

examples/kubernetes/authn/test.jwt

@@ -0,0 +1 @@
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