On Fri, Nov 04, 2016 at 10:03:21AM +0530, Akshar Kanak wrote: > Dear team > as per the documnet http://csrc.nist.gov/groups/ > STM/cmvp/documents/fips140-2/FIPS1402IG.pdf > page 150 , Its mentioned > The implementation of the nonce_explicit management logic inside the > module shall ensure that > when the nonce_explicit part of the IV exhausts the maximum number of > possible values for a given > session key (e.g., a 64-bit counter starting from 0 and increasing, > when it reaches the maximum value > of 2 64 -1), > *either party (the client or the server) that encounters this condition > triggers a handshake to establish a new encryption key – see Sections > 7.4.1.1 and 7.4.1.2 in RFC 5246*. > > is this being handled by openssl ? in the source code of openssl i am > not able find out the > exact location where this renegotiation is initiated when the counter > over flows ? (my understanding might be limited) I think we currently do an error if the calling frontend does not initiate renegotiation. Code is here: crypto/modes/gcm128.c CRYPTO_gcm128_encrypt_ctr32 These kind of checks avoid the 32bit counter overflow: if (mlen > ((U64(1) << 36) - 32) || (sizeof(len) == 8 && mlen < len)) return -1; The calling instance needs to re-iv with CRYPTO_gcm128_setiv. For TLS, if I understand correctly, the stack does intiailize the GCM cipher with a new IV on every TLS record and these cannot be that large. Ciao, Marcus -- openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users
