Function swcr_gcm

freebsd/opencrypto/cryptosoft.c:464–645

}

static int
swcr_gcm(struct swcr_session *ses, struct cryptop *crp)
{
	uint32_t blkbuf[howmany(AES_BLOCK_LEN, sizeof(uint32_t))];
	u_char *blk = (u_char *)blkbuf;
	u_char tag[GMAC_DIGEST_LEN];
	u_char iv[AES_BLOCK_LEN];
	struct crypto_buffer_cursor cc_in, cc_out;
	const u_char *inblk;
	u_char *outblk;
	union authctx ctx;
	struct swcr_auth *swa;
	struct swcr_encdec *swe;
	struct auth_hash *axf;
	struct enc_xform *exf;
	uint32_t *blkp;
	int blksz, error, ivlen, len, r, resid;

	swa = &ses->swcr_auth;
	axf = swa->sw_axf;

	bcopy(swa->sw_ictx, &ctx, axf->ctxsize);
	blksz = GMAC_BLOCK_LEN;
	KASSERT(axf->blocksize == blksz, ("%s: axf block size mismatch",
	    __func__));

	swe = &ses->swcr_encdec;
	exf = swe->sw_exf;
	KASSERT(axf->blocksize == exf->native_blocksize,
	    ("%s: blocksize mismatch", __func__));

	if ((crp->crp_flags & CRYPTO_F_IV_SEPARATE) == 0)
		return (EINVAL);

	/* Initialize the IV */
	ivlen = AES_GCM_IV_LEN;
	bcopy(crp->crp_iv, iv, ivlen);

	/* Supply MAC with IV */
	axf->Reinit(&ctx, iv, ivlen);

	/* Supply MAC with AAD */
	if (crp->crp_aad != NULL) {
		len = rounddown(crp->crp_aad_length, blksz);
		if (len != 0)
			axf->Update(&ctx, crp->crp_aad, len);
		if (crp->crp_aad_length != len) {
			memset(blk, 0, blksz);
			memcpy(blk, (char *)crp->crp_aad + len,
			    crp->crp_aad_length - len);
			axf->Update(&ctx, blk, blksz);
		}
	} else {
		crypto_cursor_init(&cc_in, &crp->crp_buf);
		crypto_cursor_advance(&cc_in, crp->crp_aad_start);
		for (resid = crp->crp_aad_length; resid >= blksz;
		     resid -= len) {
			len = crypto_cursor_seglen(&cc_in);