/*
|
* The contents of this file are subject to the terms of the Common Development and
|
* Distribution License (the License). You may not use this file except in compliance with the
|
* License.
|
*
|
* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
|
* specific language governing permission and limitations under the License.
|
*
|
* When distributing Covered Software, include this CDDL Header Notice in each file and include
|
* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
|
* Header, with the fields enclosed by brackets [] replaced by your own identifying
|
* information: "Portions Copyright [year] [name of copyright owner]".
|
*
|
* Copyright 2012-2016 ForgeRock AS.
|
* Portions Copyright 2026 3A Systems, LLC.
|
*/
|
package org.opends.dsml.protocol;
|
|
import java.io.IOException;
|
import java.io.InputStream;
|
import java.net.HttpURLConnection;
|
import java.net.InetAddress;
|
import java.net.URI;
|
import java.net.URLConnection;
|
import java.net.UnknownHostException;
|
import java.util.Arrays;
|
import java.util.Collections;
|
import java.util.HashSet;
|
import java.util.Locale;
|
import java.util.Set;
|
|
import org.forgerock.opendj.ldap.ByteString;
|
import org.forgerock.opendj.ldap.ByteStringBuilder;
|
import org.w3c.dom.Element;
|
|
/**
|
* A utility class to assist in converting DsmlValues (in Objects) into
|
* the required ByteStrings, and back again.
|
*/
|
class ByteStringUtility
|
{
|
/** Number of bytes read from a dereferenced URI per iteration. */
|
private static final int READ_CHUNK = 2048;
|
|
/** Connect timeout (ms) applied when dereferencing an anyURI value. */
|
private static final int CONNECT_TIMEOUT_MS = 10000;
|
|
/** Read timeout (ms) applied when dereferencing an anyURI value. */
|
private static final int READ_TIMEOUT_MS = 30000;
|
|
/**
|
* Whether xsd:anyURI values are dereferenced (fetched) server-side.
|
* <p>
|
* Disabled by default: fetching an attacker-supplied URI on the server is a
|
* server-side request forgery, local-file disclosure and unbounded-read DoS
|
* primitive (GHSA-68r5-9hpg-7qw9). When disabled, an anyURI value is stored
|
* verbatim (its string form) instead of being dereferenced.
|
*/
|
private static volatile boolean dereferenceUri;
|
|
/** URI schemes that may be dereferenced when {@link #dereferenceUri} is enabled. */
|
private static volatile Set<String> allowedUriSchemes =
|
Collections.unmodifiableSet(new HashSet<>(Arrays.asList("http", "https")));
|
|
/** Maximum number of bytes read from a dereferenced URI (10 MiB by default). */
|
private static volatile long maxUriContentLength = 10L * 1024 * 1024;
|
|
/**
|
* Enables or disables server-side dereferencing of xsd:anyURI values.
|
*
|
* @param enabled {@code true} to fetch anyURI values (subject to the scheme
|
* allowlist, address filter and size cap), {@code false} to
|
* store them verbatim.
|
*/
|
static void setDereferenceUri(boolean enabled)
|
{
|
dereferenceUri = enabled;
|
}
|
|
/**
|
* Sets the schemes that may be dereferenced from a comma-separated list.
|
*
|
* @param schemes comma-separated scheme names (e.g. {@code "http,https"}).
|
*/
|
static void setAllowedUriSchemes(String schemes)
|
{
|
Set<String> parsed = new HashSet<>();
|
for (String scheme : schemes.split(","))
|
{
|
String trimmed = scheme.trim();
|
if (!trimmed.isEmpty())
|
{
|
parsed.add(trimmed.toLowerCase(Locale.ROOT));
|
}
|
}
|
allowedUriSchemes = Collections.unmodifiableSet(parsed);
|
}
|
|
/**
|
* Sets the maximum number of bytes read from a dereferenced URI.
|
*
|
* @param maxLength the maximum size, in bytes; must be positive.
|
* @throws IllegalArgumentException if the size is zero or negative.
|
*/
|
static void setMaxUriContentLength(long maxLength)
|
{
|
if (maxLength <= 0)
|
{
|
throw new IllegalArgumentException(
|
"The maximum anyURI content length must be positive, but was: " + maxLength);
|
}
|
maxUriContentLength = maxLength;
|
}
|
|
/**
|
* Returns a ByteString from a DsmlValue Object.
|
*
|
* @param obj
|
* the DsmlValue object.
|
* @return a new ByteString object with the value, or null if val was null,
|
* or if it could not be converted.
|
* @throws IOException if any problems occurred retrieving an anyURI value.
|
*/
|
public static ByteString convertValue(Object obj) throws IOException
|
{
|
if (obj == null)
|
{
|
return null;
|
}
|
else if (obj instanceof String)
|
{
|
return ByteString.valueOfUtf8((String) obj);
|
}
|
else if (obj instanceof byte[])
|
{
|
return ByteString.wrap((byte[]) obj);
|
}
|
else if (obj instanceof URI)
|
{
|
return convertUri((URI) obj);
|
}
|
else if (obj instanceof Element)
|
{
|
Element element = (Element) obj;
|
return ByteString.valueOfUtf8(element.getTextContent());
|
}
|
return null;
|
}
|
|
/**
|
* Converts an xsd:anyURI value into a ByteString.
|
* <p>
|
* Unless dereferencing has been explicitly enabled, the URI is treated as an
|
* opaque string and is not fetched. When enabled, the scheme must be on the
|
* allowlist, the target must not resolve to a loopback/link-local/private
|
* address (SSRF hardening), HTTP redirects are refused (following one would
|
* connect to a host that never went through the address filter) and the
|
* amount of data read is capped.
|
* <p>
|
* Known limitation: the address filter and the subsequent connection resolve
|
* the host name independently, so DNS records changing between the two
|
* lookups (DNS rebinding) can still direct the fetch at an internal address.
|
* The JVM's positive DNS cache ({@code networkaddress.cache.ttl}, 30 seconds
|
* by default) narrows this window but does not close it; only enable
|
* dereferencing for trusted clients.
|
*
|
* @param uri the anyURI value.
|
* @return the resulting ByteString.
|
* @throws IOException if the URI is rejected or an I/O error occurs.
|
*/
|
static ByteString convertUri(URI uri) throws IOException
|
{
|
if (!dereferenceUri)
|
{
|
// Secure default: do not fetch remote or local content.
|
return ByteString.valueOfUtf8(uri.toString());
|
}
|
|
String scheme = uri.getScheme();
|
if (scheme == null || !allowedUriSchemes.contains(scheme.toLowerCase(Locale.ROOT)))
|
{
|
throw new IOException(
|
"Refusing to dereference anyURI value with disallowed scheme: " + uri);
|
}
|
assertHostAllowed(uri);
|
|
URLConnection connection = uri.toURL().openConnection();
|
connection.setConnectTimeout(CONNECT_TIMEOUT_MS);
|
connection.setReadTimeout(READ_TIMEOUT_MS);
|
if (connection instanceof HttpURLConnection)
|
{
|
HttpURLConnection httpConnection = (HttpURLConnection) connection;
|
httpConnection.setInstanceFollowRedirects(false);
|
assertNotRedirect(httpConnection.getResponseCode(), uri);
|
}
|
try (InputStream is = connection.getInputStream())
|
{
|
return readCapped(is, uri);
|
}
|
}
|
|
/**
|
* Rejects HTTP 3xx responses: the redirect target has not been validated by
|
* {@link #assertHostAllowed}, so following it would let an allowlisted public
|
* host bounce the gateway onto an internal or metadata address.
|
*
|
* @param responseCode the HTTP response code.
|
* @param uri the anyURI value being dereferenced.
|
* @throws IOException if the response is a redirect.
|
*/
|
static void assertNotRedirect(int responseCode, URI uri) throws IOException
|
{
|
if (responseCode >= 300 && responseCode < 400)
|
{
|
throw new IOException("Refusing to follow redirect (HTTP " + responseCode
|
+ ") while dereferencing anyURI value: " + uri);
|
}
|
}
|
|
/**
|
* Reads a stream into a ByteString, enforcing the configured size cap.
|
*
|
* @param is the stream to read.
|
* @param uri the anyURI value being dereferenced, for diagnostics.
|
* @return the stream content.
|
* @throws IOException on I/O error, or if the content exceeds the cap.
|
*/
|
static ByteString readCapped(InputStream is, URI uri) throws IOException
|
{
|
ByteStringBuilder bsb = new ByteStringBuilder();
|
while (bsb.appendBytes(is, READ_CHUNK) != -1)
|
{
|
if (bsb.length() > maxUriContentLength)
|
{
|
throw new IOException("anyURI content exceeds the maximum allowed size of "
|
+ maxUriContentLength + " bytes: " + uri);
|
}
|
}
|
return bsb.toByteString();
|
}
|
|
/**
|
* Rejects a URI whose host resolves (in whole or in part) to a non-routable
|
* or otherwise internal address, to prevent server-side request forgery
|
* against internal services and the cloud metadata endpoint.
|
*
|
* @param uri the anyURI value being dereferenced.
|
* @throws IOException if the host is missing, unresolvable or internal.
|
*/
|
static void assertHostAllowed(URI uri) throws IOException
|
{
|
String host = uri.getHost();
|
if (host == null)
|
{
|
throw new IOException("Refusing to dereference anyURI value with no host: " + uri);
|
}
|
InetAddress[] addresses;
|
try
|
{
|
addresses = InetAddress.getAllByName(host);
|
}
|
catch (UnknownHostException e)
|
{
|
throw new IOException("Unable to resolve anyURI host: " + host, e);
|
}
|
for (InetAddress address : addresses)
|
{
|
if (isInternalAddress(address))
|
{
|
throw new IOException("Refusing to dereference anyURI value targeting a "
|
+ "non-routable/internal address: " + host + " -> " + address.getHostAddress());
|
}
|
}
|
}
|
|
/**
|
* Returns {@code true} if the address is one the gateway must not connect to
|
* on behalf of a request: loopback, wildcard, link-local (covers the
|
* 169.254.169.254 metadata endpoint), site-local/private, multicast, an
|
* IANA-reserved IPv4 range (including 100.64.0.0/10, home of the Alibaba
|
* Cloud metadata endpoint 100.100.100.200), or an IPv6 unique-local address
|
* (fc00::/7).
|
*/
|
static boolean isInternalAddress(InetAddress address)
|
{
|
if (address.isLoopbackAddress() || address.isAnyLocalAddress()
|
|| address.isLinkLocalAddress() || address.isSiteLocalAddress()
|
|| address.isMulticastAddress())
|
{
|
return true;
|
}
|
byte[] bytes = address.getAddress();
|
if (bytes.length == 4)
|
{
|
int b0 = bytes[0] & 0xff;
|
int b1 = bytes[1] & 0xff;
|
return b0 == 0 // 0.0.0.0/8 "this network"
|
|| (b0 == 100 && (b1 & 0xc0) == 0x40) // 100.64.0.0/10 CGNAT
|
|| (b0 == 192 && b1 == 0 && (bytes[2] & 0xff) == 0) // 192.0.0.0/24 IETF assignments
|
|| (b0 == 198 && (b1 & 0xfe) == 18) // 198.18.0.0/15 benchmarking
|
|| b0 >= 240; // 240.0.0.0/4 reserved + broadcast
|
}
|
// IPv6 unique-local addresses (fc00::/7) are not covered by isSiteLocalAddress().
|
return bytes.length == 16 && (bytes[0] & 0xfe) == 0xfc;
|
}
|
|
/**
|
* Returns a DsmlValue (Object) from an LDAP ByteString. The conversion is
|
* simplistic - try and convert it to UTF-8 and if that fails return a byte[].
|
*
|
* @param bs the ByteString returned from LDAP.
|
* @return a String or a byte[].
|
*/
|
public static Object convertByteString(ByteString bs)
|
{
|
try
|
{
|
return new String(bs.toCharArray());
|
}
|
catch (Exception e)
|
{
|
return bs.toByteArray();
|
}
|
}
|
}
|
