Re: 9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Hi Xuelei,
I did notice that P11Util has a trimZeroes() function, but I didn't call
it since I didn't want to add a new package dependency. But now that you
mention it, moving it to KeyUtil seems like the best solution.
I have submitted a revised patch to the Bugzilla ticket which does
just this:
https://bugs.openjdk.java.net/attachment.cgi?id=307action=diff
Best regards,
Pasi
On Thu, May 23, 2013 at 1:39 PM, Xuelei Fan xuelei@oracle.com wrote:
On 5/23/2013 6:03 PM, Andrew Hughes wrote:
- Original Message -
On 5/20/2013 5:28 PM, Pasi Eronen wrote:
Hi Xuelei,
It seems the PKSC11 doesn't actually have this bug.
P11KeyAgreement has a separate code path for the TlsPremasterSecret
algorithm, which strips leading zeroes if the key can be extracted from
the token. (And if the key cannot be extracted, then the token is doing
the premaster secret-master secret computation, and has to do the
stripping -- it can't be done from the Java PKSC11 provider.)
It makes sense to me.
To make sure this behavior doesn't change, I added a test case
for the PKSC11 provider to the Bugzilla (which passes with the
SunPKCS11-NSS provider without any changes).
That's great. Would you mind to contribute the regression test for
PKCS11 provider?
It's been attached to the bug report:
https://bugs.openjdk.java.net/show_bug.cgi?id=100316
Thanks Andrew!
Is there any reason the original patch can't be committed? I haven't
seen any mentioned.
It is accepted. The minor comment I mentioned in the previous mail is
that we may want to merge the functions to trim leading zeros in one
method.
There is a method sun.security.pkcs11.P11Util.trimZeroes(byte[] b) which
is used to trim leading zeros. I think it would be nice to move the
method to sun.security.util.KeyUtil, and make use of this method in the
patch of DHKeyAgreement.engineGenerateSecret(String algorithm) as well.
Pasi, what do you think?
Otherwise, the patch looks fine to me.
I can be the sponsor if you won't able to merge the changes into openJDk
workspace.
Thanks,
Xuelei
Thanks,
Xuelei
Best regards,
Pasi
On Thu, May 16, 2013 at 10:56 AM, Xuelei Fan xuelei@oracle.com
mailto:xuelei@oracle.com wrote:
Hi Pasi,
Thank you for your patience, and contribution to OpenJDK. The bug
is
accepted, and you should be able to review it at:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014618
Let's use the above bug ID to track the issue.
Your patch looks fine in general (I may have some very minor
comments
later). We also have similar problems in PKCS11 provider because
of
the
update of P11KeyAgreement.java in changeset:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
Would you like to also fix it in your patch?
Thanks again for your nice work.
Regards,
Xuelei
On 5/10/2013 5:00 PM, Pasi Eronen wrote:
AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher
suites
I reported this bug over a month of ago, but for some reason,
it's
not
yet visible at bugs.sun.com http://bugs.sun.com
http://bugs.sun.com. I've included the bug
report below just in
case.
It seems this commit from March 2012 inadvertently broke SSL/TLS
DHE
cipher suites, causing the SSL/TLS handshake to fail
approximately
1 out of 256 times:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
The commit was done to fix this bug:
http://bugs.sun.com/view_bug.do?bug_id=7146728
While generating a secret of the same length as modulus may be
the
right
choice generally speaking (and it's what e.g. IPsec uses),
SSL/TLS
uses
a different convention: leading zeroes must be stripped.
This is currently blocking us from updating our production
systems to
Java 7, so although I have not contributed to OpenJDK before, I'd
like
to submit a patch and a test case for this (I've signed the OCA
already). But before I do this, I'd like to check that the
approach
is
agreeable.
We have a separate algorithm value TlsPremasterSecret, so
behavior for other cases could stay the same. Would a patch
like this:
} else if (algorithm.equals(TlsPremasterSecret)) {
// remove leading zero bytes per RFC 5246 Section 8.1.2
int i = 0;
while ((i secret.length - 1) (secret[i] == 0)) {
i++;
}
if (i == 0) {
return new SecretKeySpec(secret,
TlsPremasterSecret);
} else {
byte[] secret2 = new byte[secret.length - i];
System.arraycopy(secret, i, secret2, 0,
secret2.length);
Re: 9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Thank you for considering this improvement. I'm planing to integrate the patch into OpenJDK workspace this week. Thanks Regards, Xuelei On 5/29/2013 3:33 PM, Pasi Eronen wrote: Hi Xuelei, I did notice that P11Util has a trimZeroes() function, but I didn't call it since I didn't want to add a new package dependency. But now that you mention it, moving it to KeyUtil seems like the best solution. I have submitted a revised patch to the Bugzilla ticket which does just this: https://bugs.openjdk.java.net/attachment.cgi?id=307action=diff Best regards, Pasi On Thu, May 23, 2013 at 1:39 PM, Xuelei Fan xuelei@oracle.com mailto:xuelei@oracle.com wrote: On 5/23/2013 6:03 PM, Andrew Hughes wrote: - Original Message - On 5/20/2013 5:28 PM, Pasi Eronen wrote: Hi Xuelei, It seems the PKSC11 doesn't actually have this bug. P11KeyAgreement has a separate code path for the TlsPremasterSecret algorithm, which strips leading zeroes if the key can be extracted from the token. (And if the key cannot be extracted, then the token is doing the premaster secret-master secret computation, and has to do the stripping -- it can't be done from the Java PKSC11 provider.) It makes sense to me. To make sure this behavior doesn't change, I added a test case for the PKSC11 provider to the Bugzilla (which passes with the SunPKCS11-NSS provider without any changes). That's great. Would you mind to contribute the regression test for PKCS11 provider? It's been attached to the bug report: https://bugs.openjdk.java.net/show_bug.cgi?id=100316 Thanks Andrew! Is there any reason the original patch can't be committed? I haven't seen any mentioned. It is accepted. The minor comment I mentioned in the previous mail is that we may want to merge the functions to trim leading zeros in one method. There is a method sun.security.pkcs11.P11Util.trimZeroes(byte[] b) which is used to trim leading zeros. I think it would be nice to move the method to sun.security.util.KeyUtil, and make use of this method in the patch of DHKeyAgreement.engineGenerateSecret(String algorithm) as well. Pasi, what do you think? Otherwise, the patch looks fine to me. I can be the sponsor if you won't able to merge the changes into openJDk workspace. Thanks, Xuelei Thanks, Xuelei Best regards, Pasi On Thu, May 16, 2013 at 10:56 AM, Xuelei Fan xuelei@oracle.com mailto:xuelei@oracle.com mailto:xuelei@oracle.com mailto:xuelei@oracle.com wrote: Hi Pasi, Thank you for your patience, and contribution to OpenJDK. The bug is accepted, and you should be able to review it at: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014618 Let's use the above bug ID to track the issue. Your patch looks fine in general (I may have some very minor comments later). We also have similar problems in PKCS11 provider because of the update of P11KeyAgreement.java in changeset: http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6 Would you like to also fix it in your patch? Thanks again for your nice work. Regards, Xuelei On 5/10/2013 5:00 PM, Pasi Eronen wrote: AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher suites I reported this bug over a month of ago, but for some reason, it's not yet visible at bugs.sun.com http://bugs.sun.com http://bugs.sun.com http://bugs.sun.com. I've included the bug report below just in case. It seems this commit from March 2012 inadvertently broke SSL/TLS DHE cipher suites, causing the SSL/TLS handshake to fail approximately 1 out of 256 times: http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6 The commit was done to fix this bug: http://bugs.sun.com/view_bug.do?bug_id=7146728 While generating a secret of the same length as modulus may be the right choice generally speaking (and it's what e.g. IPsec uses), SSL/TLS uses a different convention: leading zeroes must be stripped. This is currently blocking us from updating our production systems to Java 7, so although I have not contributed to OpenJDK before, I'd like to submit a patch and a
Re: 9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
- Original Message -
On 5/20/2013 5:28 PM, Pasi Eronen wrote:
Hi Xuelei,
It seems the PKSC11 doesn't actually have this bug.
P11KeyAgreement has a separate code path for the TlsPremasterSecret
algorithm, which strips leading zeroes if the key can be extracted from
the token. (And if the key cannot be extracted, then the token is doing
the premaster secret-master secret computation, and has to do the
stripping -- it can't be done from the Java PKSC11 provider.)
It makes sense to me.
To make sure this behavior doesn't change, I added a test case
for the PKSC11 provider to the Bugzilla (which passes with the
SunPKCS11-NSS provider without any changes).
That's great. Would you mind to contribute the regression test for
PKCS11 provider?
It's been attached to the bug report:
https://bugs.openjdk.java.net/show_bug.cgi?id=100316
Is there any reason the original patch can't be committed? I haven't seen any
mentioned.
Thanks,
Xuelei
Best regards,
Pasi
On Thu, May 16, 2013 at 10:56 AM, Xuelei Fan xuelei@oracle.com
mailto:xuelei@oracle.com wrote:
Hi Pasi,
Thank you for your patience, and contribution to OpenJDK. The bug is
accepted, and you should be able to review it at:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014618
Let's use the above bug ID to track the issue.
Your patch looks fine in general (I may have some very minor comments
later). We also have similar problems in PKCS11 provider because of
the
update of P11KeyAgreement.java in changeset:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
Would you like to also fix it in your patch?
Thanks again for your nice work.
Regards,
Xuelei
On 5/10/2013 5:00 PM, Pasi Eronen wrote:
AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher suites
I reported this bug over a month of ago, but for some reason, it's
not
yet visible at bugs.sun.com http://bugs.sun.com
http://bugs.sun.com. I've included the bug
report below just in
case.
It seems this commit from March 2012 inadvertently broke SSL/TLS DHE
cipher suites, causing the SSL/TLS handshake to fail approximately
1 out of 256 times:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
The commit was done to fix this bug:
http://bugs.sun.com/view_bug.do?bug_id=7146728
While generating a secret of the same length as modulus may be the
right
choice generally speaking (and it's what e.g. IPsec uses), SSL/TLS
uses
a different convention: leading zeroes must be stripped.
This is currently blocking us from updating our production systems to
Java 7, so although I have not contributed to OpenJDK before, I'd
like
to submit a patch and a test case for this (I've signed the OCA
already). But before I do this, I'd like to check that the approach
is
agreeable.
We have a separate algorithm value TlsPremasterSecret, so
behavior for other cases could stay the same. Would a patch
like this:
} else if (algorithm.equals(TlsPremasterSecret)) {
// remove leading zero bytes per RFC 5246 Section 8.1.2
int i = 0;
while ((i secret.length - 1) (secret[i] == 0)) {
i++;
}
if (i == 0) {
return new SecretKeySpec(secret, TlsPremasterSecret);
} else {
byte[] secret2 = new byte[secret.length - i];
System.arraycopy(secret, i, secret2, 0, secret2.length);
return new SecretKeySpec(secret2, TlsPremasterSecret);
}
}
Plus a test case (with fixed keys) that checks that leading zero is
stripped
for TlsPremasterSecret and is not stripped otherwise, be sufficient?
Best regards,
Pasi
---snip---
Synopsis:
DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Full OS version:
Tested on Windows 7 (Microsoft Windows [Version 6.1.7601]), but
occurs in
e..g OpenJDK 7 as well.
Development Kit or Runtime version:
java version 1.7.0_17
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) Client VM (build 23.7-b01, mixed mode, sharing)
Description:
When performing Diffie-Hellman key agreement for SSL/TLS, the TLS
specification (RFC 5246) says that Leading bytes of Z that
contain all zero
bits are stripped before it is used as the pre_master_secret.
However, com.sun.crypto.provider.DHKeyAgreement.java does not
Re: 9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
On 5/23/2013 6:03 PM, Andrew Hughes wrote:
- Original Message -
On 5/20/2013 5:28 PM, Pasi Eronen wrote:
Hi Xuelei,
It seems the PKSC11 doesn't actually have this bug.
P11KeyAgreement has a separate code path for the TlsPremasterSecret
algorithm, which strips leading zeroes if the key can be extracted from
the token. (And if the key cannot be extracted, then the token is doing
the premaster secret-master secret computation, and has to do the
stripping -- it can't be done from the Java PKSC11 provider.)
It makes sense to me.
To make sure this behavior doesn't change, I added a test case
for the PKSC11 provider to the Bugzilla (which passes with the
SunPKCS11-NSS provider without any changes).
That's great. Would you mind to contribute the regression test for
PKCS11 provider?
It's been attached to the bug report:
https://bugs.openjdk.java.net/show_bug.cgi?id=100316
Thanks Andrew!
Is there any reason the original patch can't be committed? I haven't seen
any mentioned.
It is accepted. The minor comment I mentioned in the previous mail is
that we may want to merge the functions to trim leading zeros in one method.
There is a method sun.security.pkcs11.P11Util.trimZeroes(byte[] b) which
is used to trim leading zeros. I think it would be nice to move the
method to sun.security.util.KeyUtil, and make use of this method in the
patch of DHKeyAgreement.engineGenerateSecret(String algorithm) as well.
Pasi, what do you think?
Otherwise, the patch looks fine to me.
I can be the sponsor if you won't able to merge the changes into openJDk
workspace.
Thanks,
Xuelei
Thanks,
Xuelei
Best regards,
Pasi
On Thu, May 16, 2013 at 10:56 AM, Xuelei Fan xuelei@oracle.com
mailto:xuelei@oracle.com wrote:
Hi Pasi,
Thank you for your patience, and contribution to OpenJDK. The bug is
accepted, and you should be able to review it at:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014618
Let's use the above bug ID to track the issue.
Your patch looks fine in general (I may have some very minor comments
later). We also have similar problems in PKCS11 provider because of
the
update of P11KeyAgreement.java in changeset:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
Would you like to also fix it in your patch?
Thanks again for your nice work.
Regards,
Xuelei
On 5/10/2013 5:00 PM, Pasi Eronen wrote:
AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher suites
I reported this bug over a month of ago, but for some reason, it's
not
yet visible at bugs.sun.com http://bugs.sun.com
http://bugs.sun.com. I've included the bug
report below just in
case.
It seems this commit from March 2012 inadvertently broke SSL/TLS DHE
cipher suites, causing the SSL/TLS handshake to fail approximately
1 out of 256 times:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
The commit was done to fix this bug:
http://bugs.sun.com/view_bug.do?bug_id=7146728
While generating a secret of the same length as modulus may be the
right
choice generally speaking (and it's what e.g. IPsec uses), SSL/TLS
uses
a different convention: leading zeroes must be stripped.
This is currently blocking us from updating our production systems to
Java 7, so although I have not contributed to OpenJDK before, I'd
like
to submit a patch and a test case for this (I've signed the OCA
already). But before I do this, I'd like to check that the approach
is
agreeable.
We have a separate algorithm value TlsPremasterSecret, so
behavior for other cases could stay the same. Would a patch
like this:
} else if (algorithm.equals(TlsPremasterSecret)) {
// remove leading zero bytes per RFC 5246 Section 8.1.2
int i = 0;
while ((i secret.length - 1) (secret[i] == 0)) {
i++;
}
if (i == 0) {
return new SecretKeySpec(secret, TlsPremasterSecret);
} else {
byte[] secret2 = new byte[secret.length - i];
System.arraycopy(secret, i, secret2, 0, secret2.length);
return new SecretKeySpec(secret2, TlsPremasterSecret);
}
}
Plus a test case (with fixed keys) that checks that leading zero is
stripped
for TlsPremasterSecret and is not stripped otherwise, be sufficient?
Best regards,
Pasi
---snip---
Synopsis:
DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Full OS version:
Tested on Windows 7 (Microsoft Windows [Version 6.1.7601]), but
occurs in
e..g OpenJDK 7 as well.
Re: 9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Hi Pasi,
Thank you for your patience, and contribution to OpenJDK. The bug is
accepted, and you should be able to review it at:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014618
Let's use the above bug ID to track the issue.
Your patch looks fine in general (I may have some very minor comments
later). We also have similar problems in PKCS11 provider because of the
update of P11KeyAgreement.java in changeset:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
Would you like to also fix it in your patch?
Thanks again for your nice work.
Regards,
Xuelei
On 5/10/2013 5:00 PM, Pasi Eronen wrote:
AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher suites
I reported this bug over a month of ago, but for some reason, it's not
yet visible at bugs.sun.com http://bugs.sun.com. I've included the bug
report below just in
case.
It seems this commit from March 2012 inadvertently broke SSL/TLS DHE
cipher suites, causing the SSL/TLS handshake to fail approximately
1 out of 256 times:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
The commit was done to fix this bug:
http://bugs.sun.com/view_bug.do?bug_id=7146728
While generating a secret of the same length as modulus may be the right
choice generally speaking (and it's what e.g. IPsec uses), SSL/TLS uses
a different convention: leading zeroes must be stripped.
This is currently blocking us from updating our production systems to
Java 7, so although I have not contributed to OpenJDK before, I'd like
to submit a patch and a test case for this (I've signed the OCA
already). But before I do this, I'd like to check that the approach is
agreeable.
We have a separate algorithm value TlsPremasterSecret, so
behavior for other cases could stay the same. Would a patch
like this:
} else if (algorithm.equals(TlsPremasterSecret)) {
// remove leading zero bytes per RFC 5246 Section 8.1.2
int i = 0;
while ((i secret.length - 1) (secret[i] == 0)) {
i++;
}
if (i == 0) {
return new SecretKeySpec(secret, TlsPremasterSecret);
} else {
byte[] secret2 = new byte[secret.length - i];
System.arraycopy(secret, i, secret2, 0, secret2.length);
return new SecretKeySpec(secret2, TlsPremasterSecret);
}
}
Plus a test case (with fixed keys) that checks that leading zero is
stripped
for TlsPremasterSecret and is not stripped otherwise, be sufficient?
Best regards,
Pasi
---snip---
Synopsis:
DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Full OS version:
Tested on Windows 7 (Microsoft Windows [Version 6.1.7601]), but occurs in
e..g OpenJDK 7 as well.
Development Kit or Runtime version:
java version 1.7.0_17
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) Client VM (build 23.7-b01, mixed mode, sharing)
Description:
When performing Diffie-Hellman key agreement for SSL/TLS, the TLS
specification (RFC 5246) says that Leading bytes of Z that contain all zero
bits are stripped before it is used as the pre_master_secret.
However, com.sun.crypto.provider.DHKeyAgreement.java does not strip leading
zero bytes. This causes approximately 1 out 256 SSL/TLS handshakes with
DH/DHE cipher suites to fail (when the leading byte happens, by chance, to
be zero).
Steps to Reproduce:
1. Start a simple JSSE socket server with -Djavax.net.debug=all.
2. Connect to the server with e.g. OpenSSL command line tool, ensuring that
DHE cipher suite gets selected (e.g. openssl s_client -cipher
DHE-RSA-AES128-SHA -connect 192.168.81.1:
http://192.168.81.1:) repeatedly. Other SSL
clients can be used -- this is not an OpenSSL bug (see below).
3. Repeat the connection. After a couple of hundred successful connections,
the connection will fail with handshake_failure alert.
4. Examine the JSSE debug logs produced by the server: the failed connection
will have a PreMaster secret that begins with zero byte
(while all other connections have non-zero byte here). For example:
SESSION KEYGEN:
PreMaster Secret:
: 00 70 C5 7E 91 38 C8 DE ED 75 3D 76 8A B5 44 69 .p...8...u=v..Di
0010: E7 32 1C EE 80 77 50 C7 A9 51 24 2E E3 15 11 30 .2...wP..Q$0
0020: 9D F6 9F BC 9D EB 5C 18 F7 A4 19 ED 1A AC 2E 0C ..\.
0030: E3 18 C5 11 B1 80 07 7D B1 C6 70 A8 D7 EB CF DD ..p.
0040: 2D B5 1D BC 01 3E 28 2A 2B 5B 38 8F EB 20 F2 A2 -(*+[8.. ..
0050: 00 07 47 F7 87 B8 99 CB EF B4 13 04 C8 8B 82 FB ..G.
Expected Result:
Expected result is that every connection succeed.
Actual Result:
Roughly one out of 256 connections fail.
Source code for an executable test case:
Java server:
import javax.net.ssl.SSLServerSocket;
import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.SSLSocket;
public class TestServer
9001039?: DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
AKA 1 out of 256 SSL/TLS handshakes fails with DHE cipher suites
I reported this bug over a month of ago, but for some reason, it's not
yet visible at bugs.sun.com. I've included the bug report below just in
case.
It seems this commit from March 2012 inadvertently broke SSL/TLS DHE
cipher suites, causing the SSL/TLS handshake to fail approximately
1 out of 256 times:
http://hg.openjdk.java.net/jdk7u/jdk7u-gate/jdk/rev/e574e475c8a6
The commit was done to fix this bug:
http://bugs.sun.com/view_bug.do?bug_id=7146728
While generating a secret of the same length as modulus may be the right
choice generally speaking (and it's what e.g. IPsec uses), SSL/TLS uses
a different convention: leading zeroes must be stripped.
This is currently blocking us from updating our production systems to
Java 7, so although I have not contributed to OpenJDK before, I'd like
to submit a patch and a test case for this (I've signed the OCA
already). But before I do this, I'd like to check that the approach is
agreeable.
We have a separate algorithm value TlsPremasterSecret, so
behavior for other cases could stay the same. Would a patch
like this:
} else if (algorithm.equals(TlsPremasterSecret)) {
// remove leading zero bytes per RFC 5246 Section 8.1.2
int i = 0;
while ((i secret.length - 1) (secret[i] == 0)) {
i++;
}
if (i == 0) {
return new SecretKeySpec(secret, TlsPremasterSecret);
} else {
byte[] secret2 = new byte[secret.length - i];
System.arraycopy(secret, i, secret2, 0, secret2.length);
return new SecretKeySpec(secret2, TlsPremasterSecret);
}
}
Plus a test case (with fixed keys) that checks that leading zero is
stripped
for TlsPremasterSecret and is not stripped otherwise, be sufficient?
Best regards,
Pasi
---snip---
Synopsis:
DHKeyAgreement calculates wrong TlsPremasterSecret 1 out of 256 times
Full OS version:
Tested on Windows 7 (Microsoft Windows [Version 6.1.7601]), but occurs in
e..g OpenJDK 7 as well.
Development Kit or Runtime version:
java version 1.7.0_17
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) Client VM (build 23.7-b01, mixed mode, sharing)
Description:
When performing Diffie-Hellman key agreement for SSL/TLS, the TLS
specification (RFC 5246) says that Leading bytes of Z that contain all zero
bits are stripped before it is used as the pre_master_secret.
However, com.sun.crypto.provider.DHKeyAgreement.java does not strip leading
zero bytes. This causes approximately 1 out 256 SSL/TLS handshakes with
DH/DHE cipher suites to fail (when the leading byte happens, by chance, to
be zero).
Steps to Reproduce:
1. Start a simple JSSE socket server with -Djavax.net.debug=all.
2. Connect to the server with e.g. OpenSSL command line tool, ensuring that
DHE cipher suite gets selected (e.g. openssl s_client -cipher
DHE-RSA-AES128-SHA -connect 192.168.81.1:) repeatedly. Other SSL
clients can be used -- this is not an OpenSSL bug (see below).
3. Repeat the connection. After a couple of hundred successful connections,
the connection will fail with handshake_failure alert.
4. Examine the JSSE debug logs produced by the server: the failed connection
will have a PreMaster secret that begins with zero byte
(while all other connections have non-zero byte here). For example:
SESSION KEYGEN:
PreMaster Secret:
: 00 70 C5 7E 91 38 C8 DE ED 75 3D 76 8A B5 44 69 .p...8...u=v..Di
0010: E7 32 1C EE 80 77 50 C7 A9 51 24 2E E3 15 11 30 .2...wP..Q$0
0020: 9D F6 9F BC 9D EB 5C 18 F7 A4 19 ED 1A AC 2E 0C ..\.
0030: E3 18 C5 11 B1 80 07 7D B1 C6 70 A8 D7 EB CF DD ..p.
0040: 2D B5 1D BC 01 3E 28 2A 2B 5B 38 8F EB 20 F2 A2 -(*+[8.. ..
0050: 00 07 47 F7 87 B8 99 CB EF B4 13 04 C8 8B 82 FB ..G.
Expected Result:
Expected result is that every connection succeed.
Actual Result:
Roughly one out of 256 connections fail.
Source code for an executable test case:
Java server:
import javax.net.ssl.SSLServerSocket;
import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.SSLSocket;
public class TestServer {
public static void main(String args[]) throws Exception {
SSLServerSocketFactory ssf = (SSLServerSocketFactory)
SSLServerSocketFactory.getDefault();
SSLServerSocket ss = (SSLServerSocket) ssf.createServerSocket();
System.out.println(Listening on port );
for (String cs : ss.getEnabledCipherSuites()) {
System.out.println(cs);
}
while (true) {
SSLSocket s = (SSLSocket) ss.accept();
System.out.println(Connected with
+s.getSession().getCipherSuite());
s.close();
}
}
}
Run as as follows:
keytool -storepass password -keypass password -genkey -keyalg RSA
-keystore test_keystore.jks -dname CN=test
javac TestServer.java
java -Djavax.net.debug=all -Djavax.net.ssl.keyStore=./test_keystore.jks
