src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java

@@ -15,44 +15,44 @@
 * limitations under the License.
 */

package org.keycloak.protocol.oidc.utils;
package org.keycloak.protocol.cas.utils;

import org.jboss.logging.Logger;
import org.keycloak.common.util.Encode;
import java.net.URI;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Pattern;

import org.keycloak.common.util.KeycloakUriBuilder;
import org.keycloak.common.util.MultivaluedHashMap;
import org.keycloak.common.util.UriUtils;
import org.keycloak.models.ClientModel;
import org.keycloak.models.Constants;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.KeycloakUriInfo;
import org.keycloak.models.RealmModel;
import org.keycloak.protocol.oidc.OIDCLoginProtocol;
import org.keycloak.protocol.cas.CASLoginProtocol;
import org.keycloak.services.Urls;
import org.keycloak.services.util.ResolveRelative;

import java.net.URI;
import java.util.Collection;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;
import org.jboss.logging.Logger;

/**
 * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
 */
public class RedirectUtils {

    private static final Logger logger = Logger.getLogger(RedirectUtils.class);
    public static final Set<String> LOOPBACK_INTERFACES = new HashSet<>(Arrays.asList("localhost", "127.0.0.1", "[::1]"));

    /**
     * This method is deprecated for performance and security reasons and it is available just for the
     * backwards compatibility. It is recommended to use some other methods of this class where the client is given as an argument
     * to the method, so we know the client, which redirect-uri we are trying to resolve.
     */
    @Deprecated
    public static String verifyRealmRedirectUri(KeycloakSession session, String redirectUri) {
        Set<String> validRedirects = getValidateRedirectUris(session);
        return verifyRedirectUri(session, null, redirectUri, validRedirects, true);
    }
    private static final Set<String> FORBIDDEN_OIDC_PARAMS = Set.of(
            CASLoginProtocol.SAMLART_RESPONSE_PARAM.toLowerCase(Locale.ROOT),
            CASLoginProtocol.TICKET_RESPONSE_PARAM.toLowerCase(Locale.ROOT)
    );

    private static final Logger logger = Logger.getLogger(RedirectUtils.class);

    public static String verifyRedirectUri(KeycloakSession session, String redirectUri, ClientModel client) {
        return verifyRedirectUri(session, redirectUri, client, true);
@@ -72,24 +72,12 @@
            if (validRedirect.startsWith("/")) {
                validRedirect = relativeToAbsoluteURI(session, rootUrl, validRedirect);
                logger.debugv("replacing relative valid redirect with: {0}", validRedirect);
                resolveValidRedirects.add(validRedirect);
            } else {
                resolveValidRedirects.add(validRedirect);
            }
            resolveValidRedirects.add(validRedirect);
        }
        return resolveValidRedirects;
    }

    @Deprecated
    private static Set<String> getValidateRedirectUris(KeycloakSession session) {
        RealmModel realm = session.getContext().getRealm();
        return session.clients().getAllRedirectUrisOfEnabledClients(realm).entrySet().stream()
          .filter(me -> me.getKey().isEnabled() && OIDCLoginProtocol.LOGIN_PROTOCOL.equals(me.getKey().getProtocol()) && !me.getKey().isBearerOnly() && (me.getKey().isStandardFlowEnabled() || me.getKey().isImplicitFlowEnabled()))
          .map(me -> resolveValidRedirects(session, me.getKey().getRootUrl(), me.getValue()))
          .flatMap(Collection::stream)
          .collect(Collectors.toSet());
    }

    public static String verifyRedirectUri(KeycloakSession session, String rootUrl, String redirectUri, Set<String> validRedirects, boolean requireRedirectUri) {
        KeycloakUriInfo uriInfo = session.getContext().getUri();
        RealmModel realm = session.getContext().getRealm();
@@ -107,47 +95,39 @@
            logger.debug("No Redirect URIs supplied");
            redirectUri = null;
        } else {
            // 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);
            if (decodedRedirectUri == null) return null;
            URI originalRedirect = toUri(redirectUri);
            if (originalRedirect == null) {
                // invalid URI passed as redirectUri
                return null;
            }

            String r = decodedRedirectUri;
            // Check for HTTP Parameter Pollution - forbidden OIDC response parameters in redirect URI
            if (containsForbiddenOidcParameters(originalRedirect)){
                return null;
            }

            // check if the passed URI allows wildcards
            boolean allowWildcards = areWildcardsAllowed(originalRedirect);

            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());
            if (valid == null && "http".equals(originalRedirect.getScheme()) && LOOPBACK_INTERFACES.contains(originalRedirect.getHost())) {
                String redirectWithDefaultPort = KeycloakUriBuilder.fromUri(originalRedirect).port(80).buildAsString();
                valid = matchesRedirects(resolveValidRedirects, redirectWithDefaultPort, allowWildcards);
            }

                StringBuilder sb = new StringBuilder();
                sb.append(r.substring(0, i));

                i = r.indexOf('/', i);
                if (i >= 0) {
                    sb.append(r.substring(i));
            if (valid != null && !originalRedirect.isAbsolute()) {
                // return absolute if the original URI is relative
                if (!redirectUri.startsWith("/")) {
                    redirectUri = "/" + redirectUri;
                }

                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
            URI redirect = toUri(redirectUri);
            redirectUri = getNormalizedRedirectUri(redirect);

            // 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);
            }

            if (valid != null && redirectUri.startsWith("/")) {
                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 + ":") && !"http".equalsIgnoreCase(scheme) && !"https".equalsIgnoreCase(scheme)) {
@@ -166,72 +146,50 @@
        }
    }

    private static boolean containsForbiddenOidcParameters(URI originalRedirect) {
        String query = originalRedirect.getRawQuery();
        if (query != null && !query.isEmpty()) {
            MultivaluedHashMap<String, String> params =UriUtils.decodeQueryString(query);
            for (String paramName : params.keySet()) {
                if (FORBIDDEN_OIDC_PARAMS.contains(paramName.toLowerCase(Locale.ROOT))) {
                    logger.warnf("Redirect URI rejected: contains forbidden OIDC parameter '%s' in query string: scheme=%s, host=%s, path=%s",
                            paramName,
                            originalRedirect.getScheme(),
                            originalRedirect.getHost(),
                            originalRedirect.getPath());
                    return true;
                }
            }
        }
        return false;
    }

    private static URI toUri(String redirectUri) {
        URI uri = null;
        if (redirectUri != null) {
        try {
            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) {
        String redirectUri = null;
        if (uri != null) {
            redirectUri = uri.normalize().toString();
            redirectUri = lowerCaseHostname(redirectUri);
        }
        return redirectUri;
    }
    // any access to parent folder /../ is unsafe with or without encoding
    //   <sep>             = / | %2F | %5C | \
    //   <dots>            = "..", including %2E and %252E (double-encoded) variants
    //   <terminator>      = / | %2F | %5C | \ | ; | %3B | %09 | %0A | %0D | %00 | end-of-input
    private final static Pattern UNSAFE_PATH_PATTERN = Pattern.compile(
            "(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|%252[eE]|\\.){2}(/|%2[fF]|%5[cC]|\\\\|;|%3[bB]|%09|%0[aAdD]|%00|$)");

    // 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 encodedRedirectUri = uriBuilder
                    .replaceQuery(null)
                    .fragment(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)
                            .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) {
        int n = redirectUri.indexOf('/', 7);
        if (n == -1) {
            return redirectUri.toLowerCase();
        } else {
            return redirectUri.substring(0, n).toLowerCase() + redirectUri.substring(n);
        }
    private static boolean areWildcardsAllowed(URI redirectUri) {
        // wildcars are only allowed if no user-info and no unparsed authority and no unsafe pattern in path
        return redirectUri.getRawUserInfo() == null
                && !(redirectUri.getRawAuthority() != null && redirectUri.getRawUserInfo() == null && redirectUri.getHost() == null && redirectUri.getPort() == -1)
                && (redirectUri.getRawPath() == null || !UNSAFE_PATH_PATTERN.matcher(redirectUri.getRawPath()).find());
    }

    private static String relativeToAbsoluteURI(KeycloakSession session, String rootUrl, String relative) {
@@ -252,18 +210,60 @@
    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 *
                int length = validRedirect.length() - 1;
                validRedirect = validRedirect.substring(0, length);
                if (r.startsWith(validRedirect)) return validRedirect;
                // strip off trailing '/'
                if (length - 1 > 0 && validRedirect.charAt(length - 1) == '/') length--;
                validRedirect = validRedirect.substring(0, length);
                if (validRedirect.equals(r)) return validRedirect;
            } else if (validRedirect.equals(redirect)) return validRedirect;
            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 {
                String validRedirectWildcard = allowWildcards ? checkValidRedirectWildcard(validRedirect) : null;
                if (validRedirectWildcard != null) {
                    // 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 = validRedirectWildcard.length() - 1;
                    validRedirectWildcard = validRedirectWildcard.substring(0, length);
                    if (r.startsWith(validRedirectWildcard)) {
                        return validRedirectWildcard;
                    }
                    // strip off trailing '/'
                    if (length - 1 > 0 && validRedirectWildcard.charAt(length - 1) == '/') {
                        length--;
                    }
                    validRedirectWildcard = validRedirectWildcard.substring(0, length);
                    if (validRedirectWildcard.equals(r)) {
                        return validRedirectWildcard;
                    }
                } else if (validRedirect.equals(redirect)) {
                    return validRedirect;
                }
            }
        }
        return null;
    }

    private static String checkValidRedirectWildcard(String validRedirect) {
        if (!validRedirect.endsWith("*") || validRedirect.contains("?") || validRedirect.contains("#")) {
            return null; // no wildcard as before
        }
        KeycloakUriBuilder uriBuilder = KeycloakUriBuilder.fromUri(validRedirect, false);
        if (uriBuilder.getPath() != null) {
            return validRedirect; // wildcard valid on path
        }
        if (uriBuilder.getAuthority() != null) {
            if (uriBuilder.getAuthority().equals("*") || uriBuilder.getAuthority().endsWith(":*")) {
                return validRedirect; // on authority just full wildcard or on port
            } else {
                // treat the wildcard after the authority
                validRedirect = validRedirect.substring(0, validRedirect.length() - 1);
                validRedirect = validRedirect + "/*";
                return validRedirect;
            }
        }
        if (uriBuilder.getSsp() != null) {
            return validRedirect; // wildcard valid on SSP
        }
        return null;
    }
@@ -284,13 +284,4 @@
        }
        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));
    }
}