Function swcr_authcompute

freebsd/opencrypto/cryptosoft.c:316–382

* Compute or verify hash. */

 * Compute or verify hash.
 */
static int
swcr_authcompute(struct swcr_session *ses, struct cryptop *crp)
{
	u_char aalg[HASH_MAX_LEN];
	const struct crypto_session_params *csp;
	struct swcr_auth *sw;
	struct auth_hash *axf;
	union authctx ctx;
	int err;

	sw = &ses->swcr_auth;

	axf = sw->sw_axf;

	csp = crypto_get_params(crp->crp_session);
	if (crp->crp_auth_key != NULL) {
		swcr_authprepare(axf, sw, crp->crp_auth_key,
		    csp->csp_auth_klen);
	}

	bcopy(sw->sw_ictx, &ctx, axf->ctxsize);

	if (crp->crp_aad != NULL)
		err = axf->Update(&ctx, crp->crp_aad, crp->crp_aad_length);
	else
		err = crypto_apply(crp, crp->crp_aad_start, crp->crp_aad_length,
		    axf->Update, &ctx);
	if (err)
		goto out;

	if (CRYPTO_HAS_OUTPUT_BUFFER(crp) &&
	    CRYPTO_OP_IS_ENCRYPT(crp->crp_op))
		err = crypto_apply_buf(&crp->crp_obuf,
		    crp->crp_payload_output_start, crp->crp_payload_length,
		    axf->Update, &ctx);
	else
		err = crypto_apply(crp, crp->crp_payload_start,
		    crp->crp_payload_length, axf->Update, &ctx);
	if (err)
		goto out;

	if (csp->csp_flags & CSP_F_ESN)
		axf->Update(&ctx, crp->crp_esn, 4);

	axf->Final(aalg, &ctx);
	if (sw->sw_octx != NULL) {
		bcopy(sw->sw_octx, &ctx, axf->ctxsize);
		axf->Update(&ctx, aalg, axf->hashsize);
		axf->Final(aalg, &ctx);
	}

	if (crp->crp_op & CRYPTO_OP_VERIFY_DIGEST) {
		u_char uaalg[HASH_MAX_LEN];

		crypto_copydata(crp, crp->crp_digest_start, sw->sw_mlen, uaalg);
		if (timingsafe_bcmp(aalg, uaalg, sw->sw_mlen) != 0)
			err = EBADMSG;
		explicit_bzero(uaalg, sizeof(uaalg));