Am Montag, 13. Juli 2020, 18:48:56 CEST schrieb Elena Petrova: Hi Elena, > This patch extends the userspace RNG interface to make it usable for > CAVS testing. This is achieved by adding ALG_SET_DRBG_ENTROPY > option to the setsockopt interface for specifying the entropy, and using > sendmsg syscall for specifying the additional data. > > See libkcapi patch [1] to test the added functionality. The libkcapi > patch is not intended for merging into libkcapi as is: it is only a > quick plug to manually verify that the extended AF_ALG RNG interface > generates the expected output on DRBG800-90A CAVS inputs. As I am responsible for developing such CAVS/ACVP harness as well, I played with the idea of going through AF_ALG. I discarded it because I do not see the benefit why we should add an interface solely for the purpose of testing. Further, it is a potentially dangerous one because the created instance of the DRBG is "seeded" from data provided by the caller. Thus, I do not see the benefit from adding that extension, widening a user space interface solely for the purpose of CAVS testing. I would not see any other benefit we have with this extension. In particular, this interface would then be always there. What I could live with is an interface that can be enabled at compile time for those who want it. Besides, when you want to do CAVS testing, the following ciphers are still not testable and thus this patch would only be a partial solution to get the testing covered: - AES KW (you cannot get the final IV out of the kernel - I played with the idea to return the IV through AF_ALG, but discarded it because of the concern above) - OFB/CFB MCT testing (you need the IV from the last round - same issue as for AES KW) - RSA - DH - ECDH With these issues, I would assume you are better off creating your own kernel module just like I did that externalizes the crypto API to user space but is only available on your test kernel and will not affect all other users. Ciao Stephan
