From 71aa94e99fd15e67ca200820c722f7ec5a3a97ad Mon Sep 17 00:00:00 2001
From: Jacek Kowalski <Jacek@jacekk.info>
Date: Tue, 03 Nov 2026 21:04:42 +0000
Subject: [PATCH] Require HTTPS for proxy granting ticket callback by default
---
README.md | 3 +++
src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java | 17 ++++++++++++++---
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/README.md b/README.md
index 3c48f4b..e0f0c1c 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,9 @@
In such case append `/login` to the CAS URL to get the "login URL".
Similarly append `/serviceValidate` to get the "validate URL".
+Proxy callback URLs (`pgtUrl`) must match the client's redirect URIs and use HTTPS.
+Plain HTTP is accepted only if the realm's "Require SSL" setting allows it.
+
## Disclaimer
This plugin was implemented from scratch to comply to the official CAS protocol specification,
diff --git a/src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java b/src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java
index f510ebe..422c760 100644
--- a/src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java
+++ b/src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java
@@ -18,6 +18,7 @@
import org.keycloak.services.managers.UserSessionCrossDCManager;
import org.keycloak.services.util.DefaultClientSessionContext;
+import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.HexFormat;
@@ -228,16 +229,26 @@
}
protected void createProxyGrant(String pgtUrl) {
- if ( RedirectUtils.verifyRedirectUri(session, pgtUrl, client) == null ) {
+ String verifiedPgtUrl = RedirectUtils.verifyRedirectUri(session, pgtUrl, client);
+ if (verifiedPgtUrl == null) {
event.error(Errors.INVALID_REQUEST);
throw new CASValidationException(CASErrorCode.INVALID_PROXY_CALLBACK, "Proxy callback is invalid", Response.Status.BAD_REQUEST);
}
+ // The callback receives a PGT, so require HTTPS unless the realm's "Require SSL" setting allows plain HTTP for the host
+ URI pgtUri = URI.create(verifiedPgtUrl);
+ boolean isHttps = "https".equalsIgnoreCase(pgtUri.getScheme());
+ boolean isHttp = "http".equalsIgnoreCase(pgtUri.getScheme());
+ if (pgtUri.getHost() == null || !(isHttps || (isHttp && !realm.getSslRequired().isRequired(pgtUri.getHost())))) {
+ event.error(Errors.INVALID_REQUEST);
+ throw new CASValidationException(CASErrorCode.INVALID_PROXY_CALLBACK, "Proxy callback must use HTTPS", Response.Status.BAD_REQUEST);
+ }
+
String pgtIou = getPGTIOU();
- String pgtId = getPGT(session, clientSession, pgtUrl);
+ String pgtId = getPGT(session, clientSession, verifiedPgtUrl);
try {
- HttpGet request = new HttpGet(new URIBuilder(pgtUrl).setParameter("pgtIou",pgtIou).setParameter("pgtId",pgtId).build());
+ HttpGet request = new HttpGet(new URIBuilder(verifiedPgtUrl).setParameter("pgtIou",pgtIou).setParameter("pgtId",pgtId).build());
request.setConfig(PGT_CALLBACK_REQUEST_CONFIG);
HttpClient httpClient = session.getProvider(HttpClientProvider.class).getHttpClient();
--
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