RFR: 8289301: P11Cipher should not throw out of bounds exception during padding [v2]

Valerie Peng valeriep at openjdk.org
Thu Jun 30 23:00:52 UTC 2022

On Tue, 28 Jun 2022 13:20:53 GMT, zzambers <duke at openjdk.org> wrote:

>> SunPkcs11 provider throws out of bounds exception during encryption when specific conditions are met.
>> Exception:
>> Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 32
>> 	at java.base/java.util.Arrays.rangeCheck(Arrays.java:725)
>> 	at java.base/java.util.Arrays.fill(Arrays.java:3308)
>> 	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Cipher$PKCS5Padding.setPaddingBytes(P11Cipher.java:96)
>> 	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Cipher.implDoFinal(P11Cipher.java:813)
>> 	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Cipher.engineDoFinal(P11Cipher.java:585)
>> 	at java.base/javax.crypto.Cipher.doFinal(Cipher.java:2417)
>> ...
>> Details:
>> This problems happens when reqBlockUpdates is true and implUpdate, which does not end on block boundary, is performed followed by final implUpdate, which ends exactly on block boundary. In that case final implUpdate fills padBuffer and then just returns. [1] Following implDoFinal then tries to add padding and throws OOB exception. Problem is, that in this case (input is multiple of block size) whole padding block should be added, but there is no space for it in padBuffer causing OOB exception.
>> Solution:
>> Solution is to detect this case (implDoFinal is called with full padBuffer) and to perform additional C_EncryptUpdate to free up padBuffer so that padBuffer can than be used to add whole new padding block.
>> [1] https://github.com/openjdk/jdk/blob/d4eeeb82cb2288973a6a247c54513f7e1c6b58f0/src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11Cipher.java#L622
> zzambers has updated the pull request incrementally with one additional commit since the last revision:
>   Bug number and copyright date

test/jdk/sun/security/pkcs11/Cipher/TestPaddingOOB.java line 61:

> 59:         off += c.doFinal(plainArr, 1, plainArr.length - 1, encArr, off);
> 60:         if (off != 2 * bs) {
> 61:             throw new Exception("Unexpected encrypted size (array)");

nit: add the value of "off" to the exception message which may come in handy if the test were to fail later.

test/jdk/sun/security/pkcs11/Cipher/TestPaddingOOB.java line 67:

> 65:         off = c.doFinal(encArr, 0, encArr.length, plainArr2, 0);
> 66:         if (off != bs) {
> 67:             throw new Exception("Unexpected decrypted size (array)");

nit: add the value of "off" to the exception message which may come in handy if the test were to fail later.


PR: https://git.openjdk.org/jdk/pull/9310

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