gcp-iap-auth is a simple server implementation and package in
Go for helping you secure your web apps running on GCP
behind a
Google Cloud Platform's IAP (Identity-Aware Proxy) by validating IAP signed headers in the requests.
Validating signed headers helps you protect your app from the following kinds of risks:
- IAP is accidentally disabled;
- Misconfigured firewalls;
- Access from within the project.
go get -u github.com/imkira/gcp-iap-auth/jwtThe following is just an excerpt of the provided simple.go example:
// Here we validate the tokens in all requests going to
// our server at http://127.0.0.1:12345/auth
// For valid tokens we return 200, otherwise 401.
func AuthHandler(w http.ResponseWriter, req *http.Request) {
if err := jwt.ValidateRequestClaims(req, cfg); err != nil {
w.WriteHeader(http.StatusUnauthorized)
} else {
w.WriteHeader(http.StatusOK)
}
}For advanced usage, make sure to check the available documentation here.
Binary Releases are provided for convenience.
After downloading it, you can execute it like:
gcp-iap-auth --audiences=YOUR_AUDIENCEConstruction of the YOUR_AUDIENCE string is covered here
HTTPS is also supported. Just make sure you give it the cert/key files:
gcp-iap-auth --audiences=YOUR_AUDIENCE --tls-cert=PATH_TO_CERT_FILE --tls-key=PATH_TO_KEY_FILEIt is also possible to use environment variables instead of flags.
Just prepend GCP_IAP_AUTH_ to the flag name (in CAPS and with - replaced by _) and you're good to go (eg: GCP_IAP_AUTH_AUDIENCES replaces --audiences)
For help, just check usage:
gcp-iap-auth --helpIn this mode the gcp-iap-auth server runs as a proxy in front of another web
app. The JWT header will be checked and requests with a valid header will be
passed to the backend, while all other requests will return HTTP error 401.
gcp-iap-auth --audiences=YOUR_AUDIENCE --backend=http://localhost:8080In proxy mode you may optionally specify a header that will be filled with the
validated email address from the JWT token. The value will only contain the
email address, eg: [email protected], unlike the x-goog-authenticated-user-email
header this does not contain a namespace prefix, making this approach suitable
for backend apps which only want an email address.
gcp-iap-auth --audiences=YOUR_AUDIENCE --backend=http://localhost:8080 --email-header=X-WEBAUTH-USERYou can also integrate gcp-iap-auth server with NGINX
using the
http_auth_request_module.
The important part is as follows (full nginx.conf example file here):
upstream AUTH_SERVER_UPSTREAM {
server AUTH_SERVER_ADDR:AUTH_SERVER_PORT;
}
upstream APP_SERVER_UPSTREAM {
server APP_SERVER_ADDR:APP_SERVER_PORT;
}
server {
server_name APP_DOMAIN;
location = /gcp-iap-auth {
internal;
proxy_pass http://AUTH_SERVER_UPSTREAM/auth;
proxy_pass_request_body off;
proxy_pass_request_headers off;
proxy_set_header X-Goog-IAP-JWT-Assertion $http_x_goog_iap_jwt_assertion;
}
location / {
auth_request /gcp-iap-auth;
proxy_pass http://APP_SERVER_UPSTREAM;
}
}
Please note:
- Replace
AUTH_SERVER_UPSTREAM,AUTH_SERVER_ADDR, andAUTH_SERVER_PORTwith the data about yourgcp-iap-authserver. - Replace
APP_SERVER_UPSTREAM,APP_SERVER_ADDR, andAPP_SERVER_PORTwith the data about your own web app server. - Replace
APP_DOMAINwith the domain(s) you set up in your GCP IAP settings. gcp-iap-authonly needs to receive the originalX-Goog-IAP-JWT-Assertionheader sent by Google, so you can and you are advised to disable proxying the original request body and other headers. Not only it is unecessary you may leak information you may not want to.- Please adjust appropriately (you may want to use HTTPS instead of HTTP, multiple domains, etc.). This example is just provided for reference.
Docker images are provided for convenience.
docker run --rm -e GCP_IAP_AUTH_AUDIENCES=YOUR_AUDIENCE imkira/gcp-iap-authFor advanced usage, please read the instructions inside.
A simple way to use it with kubernetes and without any other dependencies is to run it as a reverse proxy that validates and forwards requests to a backend server.
- name: gcp-iap-auth
image: imkira/gcp-iap-auth:0.0.5
env:
- name: GCP_IAP_AUTH_AUDIENCES
value: "YOUR_AUDIENCE"
- name: GCP_IAP_AUTH_LISTEN_PORT
value: "1080"
- name: GCP_IAP_AUTH_BACKEND
value: "http://YOUR_BACKEND_SERVER"
ports:
- name: proxy
containerPort: 1080
readinessProbe:
httpGet:
path: /healthz
scheme: HTTP
port: proxy
periodSeconds: 1
timeoutSeconds: 1
successThreshold: 1
failureThreshold: 10
livenessProbe:
httpGet:
path: /healthz
scheme: HTTP
port: proxy
timeoutSeconds: 5
initialDelaySeconds: 10You can use it with kubernetes in different ways, but I personally recommend running it as a sidecar container by adding it to, say, an existing NGINX container:
- name: nginx
# your nginx container should go here...
- name: gcp-iap-auth
image: imkira/gcp-iap-auth:0.0.5
env:
- name: GCP_IAP_AUTH_AUDIENCES
value: "YOUR_AUDIENCE"
- name: GCP_IAP_AUTH_LISTEN_PORT
value: "1080"
ports:
- name: auth
containerPort: 1080
readinessProbe:
httpGet:
path: /healthz
scheme: HTTP
port: auth
periodSeconds: 1
timeoutSeconds: 1
successThreshold: 1
failureThreshold: 10
livenessProbe:
httpGet:
path: /healthz
scheme: HTTP
port: auth
timeoutSeconds: 5
initialDelaySeconds: 10To use HTTPS just make sure:
- You set up
GCP_IAP_AUTH_TLS_CERT=/path/to/tls_cert_fileandGCP_IAP_AUTH_TLS_KEY=/path/to/tls_key_fileenvironment variables. - You set up volumes for secrets in kubernetes so it knows where to find them.
- Change the scheme in readiness and liveness probes to
HTTPS. - Adjust your nginx.conf as necessary to proxy pass the auth requests to gcp-iap-auth as HTTPS.
gcp-iap-auth is licensed under the MIT license:
www.opensource.org/licenses/MIT
Copyright (c) 2017 Mario Freitas. See LICENSE for further details.
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent