From 9aa92ee9a213ebd78e12a22cf93b60ce9eb7b3f7 Mon Sep 17 00:00:00 2001
From: Ricardo Martin <rmartinc@redhat.com>
Date: Thu, 18 Apr 2024 14:02:24 +0000
Subject: [PATCH] Perform exact string match if redirect URI contains userinfo, encoded slashes or parent access (#131) (#28872)
---
src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java | 122 +++++++++-------------------------------
1 files changed, 28 insertions(+), 94 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..de8fd84 100644
--- a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
+++ b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
@@ -18,8 +18,6 @@
package org.keycloak.protocol.oidc.utils;
import org.jboss.logging.Logger;
-import org.keycloak.common.util.Encode;
-import org.keycloak.common.util.KeycloakUriBuilder;
import org.keycloak.common.util.UriUtils;
import org.keycloak.models.ClientModel;
import org.keycloak.models.Constants;
@@ -34,6 +32,7 @@
import java.util.Collection;
import java.util.Set;
import java.util.TreeSet;
+import java.util.regex.Pattern;
import java.util.stream.Collectors;
/**
@@ -73,7 +72,7 @@
validRedirect = relativeToAbsoluteURI(session, rootUrl, validRedirect);
logger.debugv("replacing relative valid redirect with: {0}", validRedirect);
}
- resolveValidRedirects.add(lowerCaseHostname(validRedirect));
+ resolveValidRedirects.add(validRedirect);
}
return resolveValidRedirects;
}
@@ -111,16 +110,13 @@
return null;
}
- // 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);
- if (decodedRedirectUri == null) return null;
+ // check if the passed URI allows wildcards
+ boolean allowWildcards = areWildcardsAllowed(originalRedirect);
- String r = decodedRedirectUri;
+ String r = redirectUri;
Set<String> resolveValidRedirects = resolveValidRedirects(session, rootUrl, validRedirects);
- String valid = matchesRedirects(resolveValidRedirects, r, true);
+ String valid = matchesRedirects(resolveValidRedirects, r, allowWildcards);
if (valid == null && (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());
@@ -135,15 +131,7 @@
r = sb.toString();
- 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(originalRedirect, false);
-
- // 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) {
- valid = matchesRedirects(resolveValidRedirects, redirectUri, false);
+ valid = matchesRedirects(resolveValidRedirects, r, allowWildcards);
}
if (valid != null && !originalRedirect.isAbsolute()) {
@@ -154,10 +142,10 @@
redirectUri = relativeToAbsoluteURI(session, rootUrl, redirectUri);
}
- String scheme = decodedRedirect.getScheme();
+ String scheme = originalRedirect.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;
}
@@ -179,74 +167,22 @@
try {
uri = URI.create(redirectUri);
} catch (IllegalArgumentException cause) {
- logger.debug("Invalid redirect uri", cause);
+ logger.debugf(cause, "Invalid redirect uri %s", redirectUri);
} catch (Exception cause) {
- logger.debug("Unexpected error when parsing redirect uri", cause);
+ logger.debugf(cause, "Unexpected error when parsing redirect uri %s", redirectUri);
}
}
return uri;
}
- private static String getNormalizedRedirectUri(URI uri, boolean lower) {
- String redirectUri = null;
- if (uri != null) {
- redirectUri = uri.normalize().toString();
- if (lower) {
- redirectUri = lowerCaseHostname(redirectUri);
- }
- }
- return redirectUri;
- }
+ // any access to parent folder /../ is unsafe with or without encoding
+ private final static Pattern UNSAFE_PATH_PATTERN = Pattern.compile(
+ "(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|\\.){2}(/|%2[fF]|%5[cC]|\\\\)|(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|\\.){2}$");
- // 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) {
- if (redirectUri == null) return null;
- 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, 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;
-
- 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();
- } else {
- // Next attempt
- encodedRedirectUri = decodedRedirectUri;
- }
- }
- } catch (IllegalArgumentException iae) {
- logger.debugf("Illegal redirect URI used: %s, Details: %s", redirectUri, iae.getMessage());
- }
- logger.debugf("Was not able to decode redirect URI: %s", redirectUri);
- 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 boolean areWildcardsAllowed(URI redirectUri) {
+ // wildcars are only allowed if no user-info and no unsafe pattern in path
+ return redirectUri.getRawUserInfo() == null
+ && (redirectUri.getRawPath() == null || !UNSAFE_PATH_PATTERN.matcher(redirectUri.getRawPath()).find());
}
private static String relativeToAbsoluteURI(KeycloakSession session, String rootUrl, String relative) {
@@ -267,9 +203,16 @@
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;
+ if ("*".equals(validRedirect)) {
+ // the valid redirect * is a full wildcard for http(s) even if the redirect URI does not allow wildcards
+ return validRedirect;
+ } else if (validRedirect.endsWith("*") && !validRedirect.contains("?") && allowWildcards) {
+ // strip off the query or fragment components - we don't check them when wildcards are effective
+ int idx = redirect.indexOf('?');
+ if (idx == -1) {
+ idx = redirect.indexOf('#');
+ }
+ String r = idx == -1 ? redirect : redirect.substring(0, idx);
// strip off *
int length = validRedirect.length() - 1;
validRedirect = validRedirect.substring(0, length);
@@ -299,13 +242,4 @@
}
return redirectUri;
}
-
- private static String getFirstValidRedirectUri(Collection<String> validRedirects) {
- final String redirectUri = validRedirects.stream().findFirst().orElse(null);
- return (redirectUri != null) ? validateRedirectUriWildcard(redirectUri) : null;
- }
-
- public static String getFirstValidRedirectUri(KeycloakSession session, String rootUrl, Set<String> validRedirects) {
- return getFirstValidRedirectUri(resolveValidRedirects(session, rootUrl, validRedirects));
- }
}
--
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