Hi Vinnie
This bug is about using UrlUtil.decode() to decode a URL that is not
fully encoded, i.e. including non-ASCII characters.
The webrev is at
http://cr.openjdk.java.net/~weijun/6961765/webrev.00/
It simply delegates the call to URLDecoder.decode().
LDAP URL (RFC 4516 2.1) specifies that only <reserved>, <unreserved>,
and <pct-encoded> chars can be used, which do not include general
non-ASCII unicode. So precisely the user input in the bug report is
illegal, but since it's already a valid URL/URI in Java, we can somehow
be more friendly.
In fact, the javadoc of URLDecoder [1] also only allows these
characters, but at the same time it says --
There are two possible ways in which this decoder could deal with
illegal strings. It could either leave illegal characters alone or
it could throw an IllegalArgumentException. Which approach the
decoder takes is left to the implementation.
Now the Oracle implementation of the class "leave illegal characters
alone". In this sense, UrlUtil is not as good as URLDecoder. It neither
leaves them alone nor throws an exception.
To be more correct, I think we can update URLDecoder so that it leaves
Unicode in the "other" category (non-control, non-whitespace non-ASCII
Unicode chars, as described in URI's spec) unchanged, and throw an
exception otherwise (that is, non-ASCII, and control or space). But I'll
leave that to another RFE.
Thanks
Max
-------- Original Message --------
*Change Request ID*: 6961765
*Synopsis*: Double byte characters corrupted in DN for LDAP referrals
=== *Description*
============================================================
SYNOPSIS
--------
Double byte characters corrupted in DN for LDAP referrals
OPERATING SYSTEM
----------------
All
FULL JDK VERSION
----------------
All
DESCRIPTION
-----------
If the DN component of an LDAP URL contains double byte characters, it
is corrupted by com.sun.jndi.toolkit.url.UrlUtil.decode(). This
corruption leads to application level failures.
Consider the following scenario:
1. Application connects to an LDAP server and searches for the string
uid=???,??? (where ??? are double byte characters)
2. JNDI code receives a referral, for example:
ldap://www.test.com/uid=???,???,ou=people,ou=test,ou=test,o=test
3. The referral is then parsed to split the hostname, port number and
the DN element of the URI via
com.sun.jndi.ldap.LdapURL.parsePathAndQuery()
4. The DN element is decoded using
com.sun.jndi.toolkit.url.UrlUtil.decode()
5. This method expects the characters to be ASCII. If the characters
are non-ASCII, as in our example, then those characters are not
converted properly.
6. This corrupted DN is then passed to the LDAP server, resulting in an
unexpected failure.
TESTCASE
--------
This testcase does not represent normal application code. It highlights
the problem by calling into com.sun.* internal classes directly. This
allows the problem to be demonstrated without setting up an LDAP server.
import java.net.URI;
import java.net.URLDecoder;
import com.sun.jndi.ldap.LdapURL;
public class LdapURLTest {
public static void main (String args[]) throws Exception {
String testString =
("ldap://www.test.com/uid=\u3070\u3073\u3076,\u3079\u307C\u307E,ou=test,ou=test,ou=test,o=test";);
LdapURL ldURL = new LdapURL(testString);
System.out.println(" LDAP URL String: " + testString);
System.out.println(" decoded DN: " + ldURL.getDN());
// suggested fix demonstration
String DN;
String path = new URI(testString).getPath();
DN = path.startsWith("/") ? path.substring(1) : path;
String proposedDN = URLDecoder.decode(DN, "UTF8");
System.out.println("\nDN from proposed fix: " + proposedDN);
}
}
SUGGESTED FIX
-------------
Use java.net.URLDecoder rather than com.sun.jndi.toolkit.url.UrlUtil to
conduct the URL decoding in parsePathAndQuery().
Specifically, change the line that decodes the DN element in
com.sun.jndi.ldap.LdapURL.parsePathAndQuery() from:
DN = path.startsWith("/") ? path.substring(1) : path;
if (DN.length() > 0) {
--> DN = UrlUtil.decode(DN, "UTF8"); <--
}
to:
DN = path.startsWith("/") ? path.substring(1) : path;
if (DN.length() > 0) {
--> DN = URLDecoder.decode(DN, "UTF8"); <--
}
=== *Evaluation*
=============================================================
The URL in the testcase has an invalid encoding. Its Unicode characters
must be encoded in UTF-8. For example,
\u3070 -> \e3\81\b0 -> %5Ce3%5C81%5Cb0
