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opendnssec / SoftHSMv2

SoftHSM version 2
http://www.softhsm.org/
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AES/GCM multi-part decryption fails with CKR_BUFFER_TOO_SMALL #730

Closed jclc closed 8 months ago

jclc commented 8 months ago

I'm working on adding AES/GCM encrypt/decrypt support for OpenSC pkcs11-tool and I noticed something when testing with SoftHSM2. Encryption works fine, but C_DecryptUpdate always fails with CKR_BUFFER_TOO_SMALL. This error doesn't really make any sense, since the function is always given an output buffer of 1024 bytes

Decryption in a single step using C_Decrypt works fine. pkcs11-tool uses this for inputs less or equal to 1024 bytes.

jclc commented 8 months ago

My mistake. I missed the part where AEAD methods are not meant to return any decoded plaintext until the entire operation is finished.