Hi Martin,
For the KeyStore case, they are mostly token objects which the extract
key info approach does not apply?
For your changes in p11_keymgmt.c, I ran into compiler error and SIGBUS
errors on two OS (mac and solaris sparc), I ended up changing variable
initializations as well as memset(...). With the updated native changes,
I adapted and re-tested my prototype changes. For reference, you can
find the updated prototype changes at:
http://cr.openjdk.java.net/~valeriep/6913047Exp/webrev.01/
Besides making changes in the keymgmet.c for getting rid of
platform-specific compilation error and SIGBUS error, I noticed that you
hardcoded the key wrapping mechanism in native code for both
getNativeKeyInfo(...)/createNativeKey() methods, it seems better to
storing the mechanism object at java side, i.e. P11Key and its
associated classes, and then pass the object to JNI code (please also
see my webrev.01)
In addition, I switched the reference counting to your model, i.e.
increase in init() and decrease in reset(), instead of the try-n-finally
model in prototype webrev.00. My earlier comment on P11Cipher class
which you should not replace the initialize() call with
ensureInitialized() call applies to all other PKCS11 classes as well.
With this approach, the KeyID field of P11Key should not be freely
accessible and directly referenced outside of P11Key class. Also, the
increase and decrease of reference counting must be paired up.
Supposedly, the reference count should not go negative, right? If the
reference counting isn't correct, the key may be freed pre-maturely?
Lastly, the reference counting is an implementation detail and I think
it's better to keep it inside the P11Key class/file and not exposing it,
i.e. through method names.
I have spent time verifying my updated prototype changes and trace the
reference counting. All look fine, except there is one regression test
failure (sun/security/tools/keytool/NssTest.java) on linux-x64 which I
am still troubleshooting. However, I will be on vacation from 10/4 to
10/21, so I want to update you on what I have so you can continue during
my vacation.
Thanks,
Valerie
On 9/18/2018 4:48 PM, Valerie Peng wrote:
Hi Martin,
I am ok with your conservation choice of only applying this when using
NSS. If we are only applying this for NSS, we should really refactor
the code to minimize the impact on callers and P11Key class. My
prototype code may be on the extreme end of minimizing changes. But
the current webrev can use some refactoring also. With your
explanation, I now understand your model better. How about the
refactoring in P11Key class? Is there a reason for not doing this? I
did test my prototype code against existing regression tests (except
the KeyStore ones as more API changes are needed for persistent keys
which I have not covered in prototype) but I ran into some strange
errors in some native p11 calls which I did not touch so I commented
them out and just checked the part of reference count, etc.
I will take a closer look at the KeyStore case and let you know.
Thanks,
Valerie
On 9/18/2018 7:29 AM, Martin Balao wrote:
Hi Valerie,
Thanks for your comments.
Here it is Webrev.11:
*
http://cr.openjdk.java.net/~mbalao/webrevs/6913047/6913047.webrev.11/
<http://cr.openjdk.java.net/%7Embalao/webrevs/6913047/6913047.webrev.11/>
*
http://cr.openjdk.java.net/~mbalao/webrevs/6913047/6913047.webrev.11.zip
<http://cr.openjdk.java.net/%7Embalao/webrevs/6913047/6913047.webrev.11.zip>
<src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11Cipher.java>
L397: That's right. I was trying to simplify the code but missed
this. Thanks.
L471: The key reference counter has to be decremented under any
exception (P11Key.decNativeKeyRef method call). But, yes, no
exception different than PKCS11Exception should be thrown. Reverted
this change.
<src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11Key.java>
L99: Comment changed. It should be better now.
L148-L149: In fact, I'd enforce this and disable the feature for all
token keys. Token keys are permanent and extracting them is risky.
This criteria was already applied when dealing with key stores
(P11Keystore class).
Yes, this feature is enabled for NSS only because it's the only
backend we currently know that is affected by this memory "leak"
issue. If there were any other software-token backend affected, we
can try this feature there too. HSMs shouldn't have any problem. I
prefer to take a more conservative approach and enable the feature
only in those cases in which it's really necessary. All other cases,
default to the previous mechanism for freeing memory.
This does not replace the PhantomReference approach; both work
together and are complementary. In cases where temporary keys feature
is disabled or when a temporary key client is not behaving correctly
(i.e.: leaking stateful operations like "cipher" or "signature" in an
intermediate state with the native key initialized), PhantomReference
approach will be the last chance to free memory. The native key
object can be destroyed (C_DestroyObject call) either from the
PhantomReference mechanism or from the temporary keys mechanism.
There shouldn't be any conflict between them. If it's destroyed
through temporary keys mechanism, then we know that the P11Key object
is alive (refereced) and thus PhantomReference destruction won't be
taking place at the same time. Once the key is deleted, keyID is set
to 0 and session to null. Thus, PhantomReference destruction won't
have any effect when executed later. If we think of the other case
(when the key is freed by PhantomReference), we have a P11Key object
with a native key initialized but with no references to it. Thus,
destroyNativeKey method won't be called and
SessionKeyRef.disposeNative is the only method that will delete the key.
L157: that's right, synchronization has to be at class level. Fixed.
L1343: It's not the same session: this.session was assigned a new
value (this.session = session;) before calling addObject.
L1363: removeObject is called for the session, inside
setKeyIDAndSession: "this.session.removeObject();". Null is set to
this.session instance variable after this call.
In regards to the refactorings you proposed, the problem I see with
moving key reference incrementing/decrementing to PKCS11.java is that
some operations are stateful. I.e.: encryption. When we initialize
the operation with C_EncryptInit, the key id is the 3rd parameter.
Destroying the key id and then doing C_EncryptUpdate sounds incorrect
to me. Have you tried the regression testing suite after this
refactoring? (I see some parts commented). In regards to removing the
tmpNativeKey parameter (used to explicitly disable the feature for
new P11Key objects), how do you handle the P11KeyStore case? We don't
want temporary keys there.
Kind regards,
Martin.-
