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

@@ -20,12 +20,17 @@
import java.net.URI;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Pattern;

import org.keycloak.OAuth2Constants;
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;
@@ -44,6 +49,22 @@

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

    private static final Set<String> FORBIDDEN_OIDC_PARAMS = Set.of(
                                                                     OAuth2Constants.CODE,
                                                                     OAuth2Constants.ID_TOKEN,
                                                                     OAuth2Constants.ACCESS_TOKEN,
                                                                     OAuth2Constants.TOKEN_TYPE,
                                                                     OAuth2Constants.EXPIRES_IN,
                                                                     OAuth2Constants.STATE,
                                                                     OAuth2Constants.ISSUER,
                                                                     OAuth2Constants.ERROR,
                                                                     OAuth2Constants.ERROR_DESCRIPTION,
                                                                     OAuth2Constants.SESSION_STATE,
                                                                     OAuth2Constants.RESPONSE,
                                                                     Constants.KC_ACTION,
                                                                     Constants.KC_ACTION_STATUS
                                                                   );

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

    public static String verifyRedirectUri(KeycloakSession session, String redirectUri, ClientModel client) {
@@ -93,6 +114,11 @@
                return null;
            }

            // 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);

@@ -133,6 +159,24 @@
        }
    }

    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) {
@@ -148,12 +192,16 @@
    }

    // 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]|\\.){2}(/|%2[fF]|%5[cC]|\\\\)|(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|\\.){2}$");
            "(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|%252[eE]|\\.){2}(/|%2[fF]|%5[cC]|\\\\|;|%3[bB]|%09|%0[aAdD]|%00|$)");

    private static boolean areWildcardsAllowed(URI redirectUri) {
        // wildcars are only allowed if no user-info and no unsafe pattern in path
        // 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());
    }

@@ -178,22 +226,57 @@
            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('#');
            } 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;
                }
                String r = idx == -1 ? redirect : redirect.substring(0, idx);
                // 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;
            }
        }
        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;
    }
@@ -214,4 +297,29 @@
        }
        return redirectUri;
    }

    public static Set<String> resolveUrlsWithRedirects(KeycloakSession session, List<String> origUrls,
                                                       String rootUrl, List<String> redirectUris, boolean returnAsOrigins) {

        Set<String> refactoredUrls = (origUrls != null) ? new HashSet<>(origUrls) : new HashSet<>();
        if (refactoredUrls.contains(Constants.INCLUDE_REDIRECTS)) {
            refactoredUrls.remove(Constants.INCLUDE_REDIRECTS);

            Set<String> redirectsToProcess = (redirectUris != null) ? new HashSet<>(redirectUris) : Collections.emptySet();
            for (String redirectUri : resolveValidRedirects(session, rootUrl, redirectsToProcess)) {
                if (isValidScheme(redirectUri)) {
                    if (returnAsOrigins) {
                        refactoredUrls.add(UriUtils.getOrigin(redirectUri));
                    } else {
                        refactoredUrls.add(redirectUri);
                    }
                }
            }
        }
        return refactoredUrls;
    }

    private static boolean isValidScheme(String url) {
        return url != null && (url.startsWith("http://") || url.startsWith("https://"));
    }
}