ssh_digest_update_buffer
int ssh_digest_update_buffer(struct ssh_digest_ctx *ctx,
return ssh_digest_update_buffer(ctx->digest, b);
ssh_digest_update_buffer(hashctx, shared_secret) != 0 ||
ssh_digest_update_buffer(hashctx, kex->session_id) != 0 ||
ssh_digest_update_buffer(hashctx, shared_secret) != 0 ||