From 760bd7b814836fca58922151abe67207cc0db1a2 Mon Sep 17 00:00:00 2001
From: Ricardo Martin <rmartinc@redhat.com>
Date: Tue, 09 Jan 2024 07:20:14 +0000
Subject: [PATCH] Escape action in the form_post.jwt and only decode path in RedirectUtils (#93) (#25995)

---
 src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java |   70 ++++++++++++++--------------------
 1 files changed, 29 insertions(+), 41 deletions(-)

diff --git a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
index 2bca7fe..1cae012 100644
--- a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
+++ b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
@@ -73,7 +73,7 @@
                 validRedirect = relativeToAbsoluteURI(session, rootUrl, validRedirect);
                 logger.debugv("replacing relative valid redirect with: {0}", validRedirect);
             }
-            resolveValidRedirects.add(lowerCaseHostname(validRedirect));
+            resolveValidRedirects.add(validRedirect);
         }
         return resolveValidRedirects;
     }
@@ -114,7 +114,7 @@
             // Make the validations against fully decoded and normalized redirect-url. This also allows wildcards (case when client configured "Valid redirect-urls" contain wildcards)
             String decodedRedirectUri = decodeRedirectUri(redirectUri);
             URI decodedRedirect = toUri(decodedRedirectUri);
-            decodedRedirectUri = getNormalizedRedirectUri(decodedRedirect, true);
+            decodedRedirectUri = getNormalizedRedirectUri(decodedRedirect);
             if (decodedRedirectUri == null) return null;
 
             String r = decodedRedirectUri;
@@ -139,7 +139,7 @@
             }
 
             // Return the original redirectUri, which can be partially encoded - for example http://localhost:8280/foo/bar%20bar%2092%2F72/3 . Just make sure it is normalized
-            redirectUri = getNormalizedRedirectUri(originalRedirect, false);
+            redirectUri = getNormalizedRedirectUri(originalRedirect);
 
             // We try to check validity also for original (encoded) redirectUrl, but just in case it exactly matches some "Valid Redirect URL" specified for client (not wildcards allowed)
             if (valid == null) {
@@ -157,7 +157,7 @@
             String scheme = decodedRedirect.getScheme();
             if (valid != null && scheme != null) {
                 // check the scheme is valid, it should be http(s) or explicitly allowed by the validation
-                if (!valid.startsWith(scheme.toLowerCase() + ":") && !"http".equalsIgnoreCase(scheme) && !"https".equalsIgnoreCase(scheme)) {
+                if (!valid.startsWith(scheme + ":") && !"http".equalsIgnoreCase(scheme) && !"https".equalsIgnoreCase(scheme)) {
                     logger.debugf("Invalid URI because scheme is not allowed: %s", redirectUri);
                     valid = null;
                 }
@@ -187,18 +187,15 @@
         return uri;
     }
 
-    private static String getNormalizedRedirectUri(URI uri, boolean lower) {
+    private static String getNormalizedRedirectUri(URI uri) {
         String redirectUri = null;
         if (uri != null) {
             redirectUri = uri.normalize().toString();
-            if (lower) {
-                redirectUri = lowerCaseHostname(redirectUri);
-            }
         }
         return redirectUri;
     }
 
-    // Decode redirectUri. We don't decode query and fragment as those can be encoded in the original URL.
+    // Decode redirectUri. Only path is decoded as other elements can be encoded in the original URL or cannot be encoded at all.
     // URL can be decoded multiple times (in case it was encoded multiple times, or some of it's parts were encoded multiple times)
     private static String decodeRedirectUri(String redirectUri) {
         if (redirectUri == null) return null;
@@ -206,28 +203,20 @@
 
         try {
             KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(redirectUri, false).preserveDefaultPort();
-            String origQuery = uriBuilder.getQuery();
-            String origFragment = uriBuilder.getFragment();
-            String origUserInfo = uriBuilder.getUserInfo();
-            String encodedRedirectUri = uriBuilder
-                    .replaceQuery(null)
-                    .fragment(null)
-                    .userInfo(null)
-                    .buildAsString();
-            String decodedRedirectUri = null;
+            if (uriBuilder.getPath() == null) {
+                return redirectUri;
+            }
+            String encodedPath = uriBuilder.getPath();
+            String decodedPath;
 
             for (int i = 0; i < MAX_DECODING_COUNT; i++) {
-                decodedRedirectUri = Encode.decode(encodedRedirectUri);
-                if (decodedRedirectUri.equals(encodedRedirectUri)) {
-                    // URL is decoded. We can return it (after attach original query and fragment)
-                    return KeycloakUriBuilder.fromUri(decodedRedirectUri, false).preserveDefaultPort()
-                            .replaceQuery(origQuery)
-                            .fragment(origFragment)
-                            .userInfo(origUserInfo)
-                            .buildAsString();
+                decodedPath = Encode.decode(encodedPath);
+                if (decodedPath.equals(encodedPath)) {
+                    // URL path is decoded. We can return it in the original redirect URI
+                    return uriBuilder.replacePath(decodedPath, false).buildAsString();
                 } else {
                     // Next attempt
-                    encodedRedirectUri = decodedRedirectUri;
+                    encodedPath = decodedPath;
                 }
             }
         } catch (IllegalArgumentException iae) {
@@ -237,18 +226,6 @@
         return null;
     }
 
-    private static String lowerCaseHostname(String redirectUri) {
-        // lower case host and scheme which are case-insensitive by spec
-        KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(redirectUri, false).preserveDefaultPort();
-        if (uriBuilder.getScheme() != null) {
-            uriBuilder.scheme(uriBuilder.getScheme().toLowerCase());
-        }
-        if (uriBuilder.getHost() != null) {
-            uriBuilder.host(uriBuilder.getHost().toLowerCase());
-        }
-        return uriBuilder.buildAsString();
-    }
-
     private static String relativeToAbsoluteURI(KeycloakSession session, String rootUrl, String relative) {
         if (rootUrl != null) {
             rootUrl = ResolveRelative.resolveRootUrl(session, rootUrl);
@@ -263,13 +240,24 @@
         return sb.toString();
     }
 
+    // removes the queryString, fragment and userInfo from the redirect
+    // to avoid comparing this when wildcards are used
+    private static String stripOffRedirectForWildcard(String redirect) {
+        return KeycloakUriBuilder.fromUri(redirect, false)
+                .preserveDefaultPort()
+                .userInfo(null)
+                .replaceQuery(null)
+                .fragment(null)
+                .buildAsString();
+    }
+
     // return the String that matched the redirect or null if not matched
     private static String matchesRedirects(Set<String> validRedirects, String redirect, boolean allowWildcards) {
         logger.tracef("matchesRedirects: redirect URL to check: %s, allow wildcards: %b, Configured valid redirect URLs: %s", redirect, allowWildcards, validRedirects);
         for (String validRedirect : validRedirects) {
             if (validRedirect.endsWith("*") && !validRedirect.contains("?") && allowWildcards) {
-                // strip off the query component - we don't check them when wildcards are effective
-                String r = redirect.contains("?") ? redirect.substring(0, redirect.indexOf("?")) : redirect;
+                // strip off the userInfo, query or fragment components - we don't check them when wildcards are effective
+                String r = stripOffRedirectForWildcard(redirect);
                 // strip off *
                 int length = validRedirect.length() - 1;
                 validRedirect = validRedirect.substring(0, length);

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