From 0eef2d743ade847107bdec4fbb8c5a29d3dc5435 Mon Sep 17 00:00:00 2001
From: mposolda <mposolda@gmail.com>
Date: Thu, 30 Mar 2023 12:20:10 +0000
Subject: [PATCH] Regressions in redirect URL verification when redirect_uri has encoded path or default port closes #16851 closes #16587

---
 src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java |   60 ++++++++++++++++++++++++++++++++++++++----------------------
 1 files changed, 38 insertions(+), 22 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 9cb314b..1cdcbbb 100644
--- a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
+++ b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
@@ -93,20 +93,6 @@
         KeycloakUriInfo uriInfo = session.getContext().getUri();
         RealmModel realm = session.getContext().getRealm();
 
-        redirectUri = decodeRedirectUri(redirectUri);
-        if (redirectUri != null) {
-            try {
-                URI uri = URI.create(redirectUri);
-                redirectUri = uri.normalize().toString();
-            } catch (IllegalArgumentException cause) {
-                logger.debug("Invalid redirect uri", cause);
-                return null;
-            } catch (Exception cause) {
-                logger.debug("Unexpected error when parsing redirect uri", cause);
-                return null;
-            }
-        }
-
         if (redirectUri == null) {
             if (!requireRedirectUri) {
                 redirectUri = getSingleValidRedirectUri(validRedirects);
@@ -120,12 +106,15 @@
             logger.debug("No Redirect URIs supplied");
             redirectUri = null;
         } else {
-            redirectUri = lowerCaseHostname(redirectUri);
+            // 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);
+            decodedRedirectUri = getNormalizedRedirectUri(decodedRedirectUri);
+            if (decodedRedirectUri == null) return null;
 
-            String r = redirectUri;
+            String r = decodedRedirectUri;
             Set<String> resolveValidRedirects = resolveValidRedirects(session, rootUrl, validRedirects);
 
-            boolean valid = matchesRedirects(resolveValidRedirects, r);
+            boolean valid = matchesRedirects(resolveValidRedirects, r, true);
 
             if (!valid && (r.startsWith(Constants.INSTALLED_APP_URL) || r.startsWith(Constants.INSTALLED_APP_LOOPBACK)) && r.indexOf(':', Constants.INSTALLED_APP_URL.length()) >= 0) {
                 int i = r.indexOf(':', Constants.INSTALLED_APP_URL.length());
@@ -140,8 +129,17 @@
 
                 r = sb.toString();
 
-                valid = matchesRedirects(resolveValidRedirects, r);
+                valid = matchesRedirects(resolveValidRedirects, r, true);
             }
+
+            // 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(redirectUri);
+
+            // 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) {
+                valid = matchesRedirects(resolveValidRedirects, redirectUri, false);
+            }
+
             if (valid && redirectUri.startsWith("/")) {
                 redirectUri = relativeToAbsoluteURI(session, rootUrl, redirectUri);
             }
@@ -155,6 +153,23 @@
         }
     }
 
+    private static String getNormalizedRedirectUri(String redirectUri) {
+        if (redirectUri != null) {
+            try {
+                URI uri = URI.create(redirectUri);
+                redirectUri = uri.normalize().toString();
+            } catch (IllegalArgumentException cause) {
+                logger.debug("Invalid redirect uri", cause);
+                return null;
+            } catch (Exception cause) {
+                logger.debug("Unexpected error when parsing redirect uri", cause);
+                return null;
+            }
+            redirectUri = lowerCaseHostname(redirectUri);
+        }
+        return redirectUri;
+    }
+
     // Decode redirectUri. We don't decode query and fragment as those can be encoded in the original URL.
     // 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) {
@@ -162,7 +177,7 @@
         int MAX_DECODING_COUNT = 5; // Max count of attempts for decoding URL (in case it was encoded multiple times)
 
         try {
-            KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(redirectUri);
+            KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(redirectUri).preserveDefaultPort();
             String origQuery = uriBuilder.getQuery();
             String origFragment = uriBuilder.getFragment();
             String encodedRedirectUri = uriBuilder
@@ -175,7 +190,7 @@
                 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)
+                    return KeycloakUriBuilder.fromUri(decodedRedirectUri).preserveDefaultPort()
                             .replaceQuery(origQuery)
                             .fragment(origFragment)
                             .buildAsString();
@@ -214,9 +229,10 @@
         return sb.toString();
     }
 
-    private static boolean matchesRedirects(Set<String> validRedirects, String redirect) {
+    private static boolean 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("?")) {
+            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 *

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