On 8/18/2016 4:49 PM, Valerie Peng wrote:
Hi Mike,
Thanks for the feedback and the detailed write up.
The scenario here is complicated by the sensitive/non-extractable keys
of PKCS#11 and the fact that java key and key specification classes
assume all relevant values being available.
Um... I think that's true for any PublicKey, but not for Secret or
Private keys. At worst, the Key object is a handle for the real key
that contains all those items, but they might not be available. At
best, most of those components will be available. I say at best,
because of the language in RSAMultiPrimePrivateCRTKey for
getOtherPrimeInfo() which says it can return null.
Only when all relevant values are available, then we will construct
the corresponding key objects. This is necessary as there are other
providers which may receive such keys and they can't handle keys like
this.
Keys can't generally move across providers AIRC? You can try and use a
key factory to convert them, but that's not guaranteed. A PKCS11
derived key isn't going to be portable to another provider without
extraction to a keyspec in any case.
Hmm.. I went back and read the JDK8 p11 guide
(https://docs.oracle.com/javase/8/docs/technotes/guides/security/p11guide.html)
and section 3.2 gives the guidance that you only use the generic
interfaces for unextractable keys. I actually think that's wrong, given
the general guidance in the JCA documentation with respect to Opaque
Keys vs transparent KeySpecs. (Hmm... I wonder if this guidance was in
the originally submitted code package documentation).
Then there's the point that even a generic Public or Private key has a
"getEncoded()" method. *bleah*
I am sure that the current PKCS11 provider code needs many
improvement/finer handlings. But I don't see a straightforward way of
"making CKA_PUBLIC_EXPONENT available" across various RSA Key classes.
This should be tracked in a different issue.
That's just one of the items. As I mentioned in another email, I think
the RSA key classes and interfaces need a bit more work and tweaking. I
wouldn't try and accomplish that quite yet.
Given the current release schedule, the deadline for this fix (P4) is
coming up in 10 days and I will be on vacation next week.
If you agree with the value of addressing this with the proposed
changes for JDK 9, then we can proceed.
Otherwise, I will defer this bug to the update release and we can
spend more time to polish this.
I think you might as well go ahead with this change. The fix you've got
should work as long as someone who generates a RSA Key pair on a PKCS11
which is both sensitive and unextractable doesn't try to cast the keys
to RSAPublic or RSAPrivate.
Mike
Valerie
On 8/18/2016 8:40 AM, Michael StJohns wrote:
On 8/17/2016 11:36 PM, Valerie Peng wrote:
Regression tests are still running, but thought that I will send the
updated webrev out and see if there are more comments.
Webrev is updated at:
http://cr.openjdk.java.net/~valeriep/8078661/webrev.01/
Thanks,
Valerie
Hi Valerie -
You know - re-reading this code I'm reminding of why PKCS11 annoys me
so much.
At line 333 (of the "new" P11Key) you grab the Token, Sensitive and
Extractable values and if the private data is sensitive or not
extractable you create a generic P11PrivateKey and return that.
However the contract for RSAKey requires that the public modulus be
returned if available, and, since its not a sensitive attribute it
probably should be available. Also, even if the key is sensitive -
if its a sensitive CRT key, then CKA_PUBLIC_EXPONENT should be
available.
That's going to be a surprise if someone tries to cast this return to
an (RSAKey) or (RSAPrivateKey). _This should be changed so a key of
the appropriate type is always created._
Also, checking for CKA_EXTRACTABLE being true, doesn't actually get
you access to the clear text information. If a key is extractable,
then it can be wrapped out under another key. The components
themselves aren't available. It's possible to have a non-sensitive,
non-extractable key where the components are retrievable, but the key
can't be wrapped out.
(Hmm... the public exponent is in RSAPublicKey and RSAPrivateCRTKey,
but should probably be in RSAKey instead).
So:
All RSA keys - even the sensitive private ones - should return
CKA_MODULUS.
All RSA Private CRT Keys - even the sensitive ones - should also
return CKA_PUBLIC_EXPONENT.
All non-sensitive RSA Private keys - should also return
CKA_PRIVATE_EXPONENT
All non-sensitive RSA Private CRT Keys - should also return
CKA_PRIME_1, CKA_PRIME_2, CKA_EXPONENT_1, CKA_EXPONENT_2 and
CKA_COEFFICIENT.
This is harder to do than it needs to be due to how
p11_objmgt.c::Java_sun_security_pkcs11_wrapper_PKCS11_C_1GetAttributeValue
is built. At lines 248 and 270, it does a check for an error return
and throws an exception if any error occurs. However, for
C_GetAttributeValue, there are a number of "non-fatal" errors that
indicate either buffer size errors or sensitivity of one or more
components or unavailability of one or more components.
Note that the error codes CKR_ATTRIBUTE_SENSITIVE,
CKR_ATTRIBUTE_TYPE_INVALID, and CKR_BUFFER_TOO_SMALL do not denote
true errors for *C_GetAttributeValue*. If a call to
*C_GetAttributeValue* returns any of these three values, then the
call must nonetheless have processed /every/ attribute in the
template supplied to *C_GetAttributeValue*. Each attribute in the
template whose value /can be/ returned by the call to
*C_GetAttributeValue* /will be/ returned by the call to
*C_GetAttributeValue*.
If you updated this slightly - maybe by adding a new method to
wrapper.PKCS11 (say GetAttributeValuesNoError) - to return the
attributes it was able to get in the call with nulls elsewhere, then
you could do all of the above in one pass.
Sorry to complicate this. Mike
ps - I don't have a current build environment set up for the JDK,
otherwise I'd code it and test it myself. I'm happy to take a swing
at it and provide you unverified code you can integrate.
On 8/17/2016 9:55 AM, Michael StJohns wrote:
On 8/16/2016 9:24 PM, Valerie Peng wrote:
Anyone has time to review a straightforward fix? The current
PKCS11 code assume that if public exponent is available for RSA
Private Key, then it's a RSA CRT key. However, not all vendor
implementation works this way. Changing to a tighter check and did
minor code-refactoring to avoid re-retrieving the attribute values.
Bug: https://bugs.openjdk.java.net/browse/JDK-8078661
Webrev: http://cr.openjdk.java.net/~valeriep/8078661/webrev.00/
Thanks,
Valerie
Given that there's a change to PKCS11 for 2.40 that says that all
RSA private key objects MUST also store CKA_PUBLIC_EXPONENT, some
change needed to be made.
Sorry - I don't think this fix will work. Or if its working on
your version of PKCS11, your version of PKCS11 is doing it wrong.
The problem is that if you specify attributes that don't exist on
the object, the underlying PKCS11 library is supposed to return
CKR_ATTRIBUTE_TYPE_INVALID. And that should trigger a thrown
exception before you ever get anything copied to your attributes.
1) Get modulus and private exponent first. That gives you the
stuff for a generic RSA private key - and if it fails, there's no
reason to continue.
2) Then get the rest of the stuff. If that fails, then you already
have the stuff you need for a normal private key.
boolean crtKey;
try {
session.token.p11.C_GetAttributeValue
(session.id(), keyID, attrs2);
- crtKey = (attrs2[0].pValue instanceof byte[]);
+ crtKey = ((attrs2[1].pValue instanceof byte[]) &&
+ (attrs2[3].pValue instanceof byte[]) &&
+ (attrs2[4].pValue instanceof byte[]) &&
+ (attrs2[5].pValue instanceof byte[]) &&
+ (attrs2[6].pValue instanceof byte[]) &&
+ (attrs2[7].pValue instanceof byte[])) ;
} catch (PKCS11Exception e) {
// ignore, assume not available
crtKey = false;
}
// Change attrs2 so it only has the additional CRT attributes (e.g.
delete CKA_MODULUS, CKA_PRIVATE_EXPONENT from the list
Replace the above with
CK_ATTRIBUTE[] attrs3 = new CK_ATTRIBUTE[] {
new CK_ATTRIBUTE(CKA_MODULUS),
new CK_ATTRIBUTE(CKA_PRIVATE_EXPONENT)
};
// no try block needed here - we want to throw the error if it occurs
session.token.p11.C_GetAttributeValue (session.id(), keyID, attrs3);
// So far so good - we have the base attributes, let's see if we
can get the additional attributes;
try {
session.token.p11.C_GetAttributeValue(session.id(),keyID, attrs2);
} catch (PKCS11Exception e) {
// we really should check the return value for one of the
non-fatal values, but let's just assume its not a CRT key
return new P11RSAPrivateNonCRTKey (session, keyID, algorithm,
keyLength, attrs2, attrs3);
}
// if we fall through then its a CRT key
// -- we should check for byte[] ness of each of the components,
and throw an error if they arent - but which error?
return new P11RSAPrivateKey (session, keyID, algorithm, keyLength,
attrs2, attrs3);
// there are cleanups necessary in other places. I'd suggest
rather than depending on the ordering of attributes, you do
assignment by CKA_ values just so someone coming later doesn't mess
things up by mistake. Also, a hell of a lot more readable.
static CK_ATTRIBUTE getAttribute (CK_ATTRIBUTE[] attrs, long
attrType) {
for (CK_ATTRIBUTE a : attrs) {
if (a.type == attrType)
return a;
}
return null; // or throw something?
}
coeff = getAtttribute(attrs,CKA_COEFFICIENT).getBigInteger();
The other possibility is to change the C code for
C_GetAttributeValues so it doesn't error out for the non-fatal
error codes and instead returns a null value attribute when the
attribute is missing.
Mike
