added jwt-key-file option, update docs

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Changes since v3.2.0
 
+- [#111](https://github.com/pusher/oauth2_proxy/pull/111) Add option for telling where to find a login.gov JWT key file (@timothy-spencer)
+
 # v3.2.0
 
 ## Release highlights

Dockerfile

@@ -11,13 +11,19 @@ COPY . .
 # Fetch dependencies
 RUN dep ensure --vendor-only
 
-# Build binary
+# Build binary and make sure there is at least an empty key file.
-RUN ./configure && make build
+#  This is useful for GCP App Engine custom runtime builds, because
+#  you cannot use multiline variables in their app.yaml, so you have to
+#  build the key into the container and then tell it where it is
+#  by setting OAUTH2_PROXY_JWT_KEY_FILE=/etc/ssl/private/jwt_signing_key.pem
+#  in app.yaml instead.
+RUN ./configure && make build && touch jwt_signing_key.pem
 
 # Copy binary to alpine
 FROM alpine:3.8
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/oauth2_proxy /bin/oauth2_proxy
+COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/jwt_signing_key.pem /etc/ssl/private/jwt_signing_key.pem
 
 RUN addgroup -S -g 2000 oauth2proxy && adduser -S -u 2000 oauth2proxy -G oauth2proxy
 USER oauth2proxy

Dockerfile.arm64

@@ -11,13 +11,19 @@ COPY . .
 # Fetch dependencies
 RUN dep ensure --vendor-only
 
-# Build binary
+# Build binary and make sure there is at least an empty key file.
-RUN ./configure && GOARCH=arm64 make build
+#  This is useful for GCP App Engine custom runtime builds, because
+#  you cannot use multiline variables in their app.yaml, so you have to
+#  build the key into the container and then tell it where it is
+#  by setting OAUTH2_PROXY_JWT_KEY_FILE=/etc/ssl/private/jwt_signing_key.pem
+#  in app.yaml instead.
+RUN ./configure && GOARCH=arm64 make build && touch jwt_signing_key.pem
 
 # Copy binary to alpine
 FROM arm64v8/alpine:3.8
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/oauth2_proxy /bin/oauth2_proxy
+COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/jwt_signing_key.pem /etc/ssl/private/jwt_signing_key.pem
 
 RUN addgroup -S -g 2000 oauth2proxy && adduser -S -u 2000 oauth2proxy -G oauth2proxy
 USER oauth2proxy

Dockerfile.armv6

@@ -11,13 +11,19 @@ COPY . .
 # Fetch dependencies
 RUN dep ensure --vendor-only
 
-# Build binary
+# Build binary and make sure there is at least an empty key file.
-RUN ./configure && GOARCH=arm GOARM=6 make build
+#  This is useful for GCP App Engine custom runtime builds, because
+#  you cannot use multiline variables in their app.yaml, so you have to
+#  build the key into the container and then tell it where it is
+#  by setting OAUTH2_PROXY_JWT_KEY_FILE=/etc/ssl/private/jwt_signing_key.pem
+#  in app.yaml instead.
+RUN ./configure && GOARCH=arm GOARM=6 make build && touch jwt_signing_key.pem
 
 # Copy binary to alpine
 FROM arm32v6/alpine:3.8
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/oauth2_proxy /bin/oauth2_proxy
+COPY --from=builder /go/src/github.com/pusher/oauth2_proxy/jwt_signing_key.pem /etc/ssl/private/jwt_signing_key.pem
 
 RUN addgroup -S -g 2000 oauth2proxy && adduser -S -u 2000 oauth2proxy -G oauth2proxy
 USER oauth2proxy

README.md

@@ -216,6 +216,13 @@ Now start the proxy up with the following options:
   -jwt-key="${OAUTH2_PROXY_JWT_KEY}"
 ```
 You can also set all these options with environment variables, for use in cloud/docker environments.
+One tricky thing that you may encounter is that some cloud environments will pass in environment
+variables in a docker env-file, which does not allow multiline variables like a PEM file.
+If you encounter this, then you can create a `jwt_signing_key.pem` file in the top level
+directory of the repo which contains the key in PEM format and then do your docker build.
+The docker build process will copy that file into your image which you can then access by
+setting the `OAUTH2_PROXY_JWT_KEY_FILE=/etc/ssl/private/jwt_signing_key.pem`
+environment variable, or by setting `-jwt-key-file=/etc/ssl/private/jwt_signing_key.pem` on the commandline.
 
 Once it is running, you should be able to go to `http://localhost:4180/` in your browser,
 get authenticated by the login.gov integration server, and then get proxied on to your
@@ -261,6 +268,7 @@ An example [oauth2_proxy.cfg](contrib/oauth2_proxy.cfg.example) config file is i
 
 ```
 Usage of oauth2_proxy:
+  -acr-values string:  optional, used by login.gov (default "http://idmanagement.gov/ns/assurance/loa/1")
   -approval-prompt string: OAuth approval_prompt (default "force")
   -authenticated-emails-file string: authenticate against emails via file (one per line)
   -azure-tenant string: go to a tenant-specific or common (tenant-independent) endpoint. (default "common")
@@ -269,10 +277,10 @@ Usage of oauth2_proxy:
   -client-secret string: the OAuth Client Secret
   -config string: path to config file
   -cookie-domain string: an optional cookie domain to force cookies to (ie: .yourcompany.com)
-  -cookie-path string: an optional cookie path to force cookies to (ie: /foo)
   -cookie-expire duration: expire timeframe for cookie (default 168h0m0s)
   -cookie-httponly: set HttpOnly cookie flag (default true)
   -cookie-name string: the name of the cookie that the oauth_proxy creates (default "_oauth2_proxy")
+  -cookie-path string: an optional cookie path to force cookies to (ie: /poc/)* (default "/")
   -cookie-refresh duration: refresh the cookie after this duration; 0 to disable
   -cookie-secret string: the seed string for secure cookies (optionally base64 encoded)
   -cookie-secure: set secure (HTTPS) cookie flag (default true)
@@ -290,6 +298,8 @@ Usage of oauth2_proxy:
   -htpasswd-file string: additionally authenticate against a htpasswd file. Entries must be created with "htpasswd -s" for SHA encryption
   -http-address string: [http://]<addr>:<port> or unix://<path> to listen on for HTTP clients (default "127.0.0.1:4180")
   -https-address string: <addr>:<port> to listen on for HTTPS clients (default ":443")
+  -jwt-key string: private key in PEM format used to sign JWT, so that you can say something like -jwt-key="${OAUTH2_PROXY_JWT_KEY}": required by login.gov
+  -jwt-key-file string: path to the private key file in PEM format used to sign the JWT so that you can say something like -jwt-key-file=/etc/ssl/private/jwt_signing_key.pem: required by login.gov
   -login-url string: Authentication endpoint
   -oidc-issuer-url: the OpenID Connect issuer URL. ie: "https://accounts.google.com"
   -oidc-jwks-url string: OIDC JWKS URI for token verification; required if OIDC discovery is disabled
@@ -302,6 +312,7 @@ Usage of oauth2_proxy:
   -provider string: OAuth provider (default "google")
   -proxy-prefix string: the url root path that this proxy should be nested under (e.g. /<oauth2>/sign_in) (default "/oauth2")
   -proxy-websockets: enables WebSocket proxying (default true)
+  -pubjwk-url string: JWK pubkey access endpoint: required by login.gov
   -redeem-url string: Token redemption endpoint
   -redirect-url string: the OAuth Redirect URL. ie: "https://internalapp.yourcompany.com/oauth2/callback"
   -request-logging: Log requests to stdout (default true)

main.go

@@ -92,7 +92,8 @@ func main() {
 
 	flagSet.String("signature-key", "", "GAP-Signature request signature key (algorithm:secretkey)")
 	flagSet.String("acr-values", "http://idmanagement.gov/ns/assurance/loa/1", "acr values string:  optional, used by login.gov")
-	flagSet.String("jwt-key", "", "private key used to sign JWT: required by login.gov")
+	flagSet.String("jwt-key", "", "private key in PEM format used to sign JWT, so that you can say something like -jwt-key=\"${OAUTH2_PROXY_JWT_KEY}\": required by login.gov")
+	flagSet.String("jwt-key-file", "", "path to the private key file in PEM format used to sign the JWT so that you can say something like -jwt-key-file=/etc/ssl/private/jwt_signing_key.pem: required by login.gov")
 	flagSet.String("pubjwk-url", "", "JWK pubkey access endpoint: required by login.gov")
 	flagSet.Bool("gcp-healthchecks", false, "Enable GCP/GKE healthcheck endpoints")
 

options.go

@@ -6,6 +6,7 @@ import (
 	"crypto/tls"
 	"encoding/base64"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -90,6 +91,7 @@ type Options struct {
 	SignatureKey    string `flag:"signature-key" cfg:"signature_key" env:"OAUTH2_PROXY_SIGNATURE_KEY"`
 	AcrValues       string `flag:"acr-values" cfg:"acr_values" env:"OAUTH2_PROXY_ACR_VALUES"`
 	JWTKey          string `flag:"jwt-key" cfg:"jwt_key" env:"OAUTH2_PROXY_JWT_KEY"`
+	JWTKeyFile      string `flag:"jwt-key-file" cfg:"jwt_key_file" env:"OAUTH2_PROXY_JWT_KEY_FILE"`
 	PubJWKURL       string `flag:"pubjwk-url" cfg:"pubjwk_url" env:"OAUTH2_PROXY_PUBJWK_URL"`
 	GCPHealthChecks bool   `flag:"gcp-healthchecks" cfg:"gcp_healthchecks" env:"OAUTH2_PROXY_GCP_HEALTHCHECKS"`
 
@@ -328,15 +330,33 @@ func parseProviderInfo(o *Options, msgs []string) []string {
 	case *providers.LoginGovProvider:
 		p.AcrValues = o.AcrValues
 		p.PubJWKURL, msgs = parseURL(o.PubJWKURL, "pubjwk", msgs)
-		if o.JWTKey == "" {
+
+		// JWT key can be supplied via env variable or file in the filesystem, but not both.
+		switch {
+		case o.JWTKey != "" && o.JWTKeyFile != "":
+			msgs = append(msgs, "cannot set both jwt-key and jwt-key-file options")
+		case o.JWTKey == "" && o.JWTKeyFile == "":
 			msgs = append(msgs, "login.gov provider requires a private key for signing JWTs")
-		} else {
+		case o.JWTKey != "":
+			// The JWT Key is in the commandline argument
 			signKey, err := jwt.ParseRSAPrivateKeyFromPEM([]byte(o.JWTKey))
 			if err != nil {
 				msgs = append(msgs, "could not parse RSA Private Key PEM")
 			} else {
 				p.JWTKey = signKey
 			}
+		case o.JWTKeyFile != "":
+			// The JWT key is in the filesystem
+			keyData, err := ioutil.ReadFile(o.JWTKeyFile)
+			if err != nil {
+				msgs = append(msgs, "could not read key file: "+o.JWTKeyFile)
+			}
+			signKey, err := jwt.ParseRSAPrivateKeyFromPEM(keyData)
+			if err != nil {
+				msgs = append(msgs, "could not parse private key from PEM file:"+o.JWTKeyFile)
+			} else {
+				p.JWTKey = signKey
+			}
 		}
 	}
 	return msgs