Fix basic auth legacy header conversion

CHANGELOG.md

@@ -43,6 +43,7 @@
 
 ## Changes since v6.1.1
 
+- [#925](https://github.com/oauth2-proxy/oauth2-rpoxy/pull/925) Fix basic auth legacy header conversion (@JoelSpeed)
 - [#916](https://github.com/oauth2-proxy/oauth2-rpoxy/pull/916) Add AlphaOptions struct to prepare for alpha config loading (@JoelSpeed)
 - [#923](https://github.com/oauth2-proxy/oauth2-proxy/pull/923) Support TLS 1.3 (@aajisaka)
 - [#918](https://github.com/oauth2-proxy/oauth2-proxy/pull/918) Fix log header output (@JoelSpeed)

pkg/apis/options/legacy_options.go

@@ -232,7 +232,8 @@ func getBasicAuthHeader(preferEmailToUser bool, basicAuthPassword string) Header
 		Values: []HeaderValue{
 			{
 				ClaimSource: &ClaimSource{
-					Claim: claim,
+					Claim:  claim,
+					Prefix: "Basic ",
 					BasicAuthPassword: &SecretSource{
 						Value: []byte(base64.StdEncoding.EncodeToString([]byte(basicAuthPassword))),
 					},

pkg/apis/options/legacy_options_test.go

@@ -329,7 +329,8 @@ var _ = Describe("Legacy Options", func() {
 			Values: []HeaderValue{
 				{
 					ClaimSource: &ClaimSource{
-						Claim: "user",
+						Claim:  "user",
+						Prefix: "Basic ",
 						BasicAuthPassword: &SecretSource{
 							Value: []byte(base64.StdEncoding.EncodeToString([]byte(basicAuthSecret))),
 						},
@@ -368,7 +369,8 @@ var _ = Describe("Legacy Options", func() {
 			Values: []HeaderValue{
 				{
 					ClaimSource: &ClaimSource{
-						Claim: "email",
+						Claim:  "email",
+						Prefix: "Basic ",
 						BasicAuthPassword: &SecretSource{
 							Value: []byte(base64.StdEncoding.EncodeToString([]byte(basicAuthSecret))),
 						},