aes: Restrict AES-GCM to at least 1B tag length #189
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The PKCS#11 specs says 0 is a valid tag length: > *ulTagBits* > length of authentication tag (output following cipher text) in bits. > Can be any value between 0 and 128. From 6.13.5 AES GCM and CCM Mechanism parameters https://docs.oasis-open.org/pkcs11/pkcs11-spec/v3.1/os/pkcs11-spec-v3.1-os.html#_Toc111203499 But OpenSSL's API requires that the tag is at least on byte when decrypting data: > EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag) > Sets the expected tag to "taglen" bytes from "tag". The tag length > can only be set before specifying an IV. "taglen" must be between > 1 and 16 (POLY1305_BLOCK_SIZE) inclusive. This call is only valid > when decrypting data. When data is encrypted, it is still possible to not read the tag though, but allowing not to set the tag when decrypting data would probably be too error prone. Signed-off-by: Jakub Jelen <[email protected]>
This verifies both Encrypt and MessageEncrypt API that zero-length tags are not accepted and the kryoptic returns non-generic error codes. Signed-off-by: Jakub Jelen <[email protected]>
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Description
The PKCS#11 specs says 0 is a valid tag length:
From 6.13.5 AES GCM and CCM Mechanism parameters
https://docs.oasis-open.org/pkcs11/pkcs11-spec/v3.1/os/pkcs11-spec-v3.1-os.html#_Toc111203499
But OpenSSL's API requires that the tag is at least on byte when
decrypting data:
When data is encrypted, it is still possible to not read the tag though,
but allowing not to set the tag when decrypting data would probably be
too error prone.
Checklist
[ ] Test suite updated with functionality tests[ ] Documentation was updated[ ] This is not a code changeReviewer's checklist: