Function swcr_encdec

freebsd/opencrypto/cryptosoft.c:100–284

* Apply a symmetric encryption/decryption algorithm. */

 * Apply a symmetric encryption/decryption algorithm.
 */
static int
swcr_encdec(struct swcr_session *ses, struct cryptop *crp)
{
	unsigned char iv[EALG_MAX_BLOCK_LEN], blk[EALG_MAX_BLOCK_LEN];
	unsigned char *ivp, *nivp, iv2[EALG_MAX_BLOCK_LEN];
	const struct crypto_session_params *csp;
	struct swcr_encdec *sw;
	struct enc_xform *exf;
	int i, blks, inlen, ivlen, outlen, resid;
	struct crypto_buffer_cursor cc_in, cc_out;
	const unsigned char *inblk;
	unsigned char *outblk;
	int error;
	bool encrypting;

	error = 0;

	sw = &ses->swcr_encdec;
	exf = sw->sw_exf;
	ivlen = exf->ivsize;

	if (exf->native_blocksize == 0) {
		/* Check for non-padded data */
		if ((crp->crp_payload_length % exf->blocksize) != 0)
			return (EINVAL);

		blks = exf->blocksize;
	} else
		blks = exf->native_blocksize;

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

	if (crp->crp_cipher_key != NULL) {
		csp = crypto_get_params(crp->crp_session);
		error = exf->setkey(sw->sw_kschedule,
		    crp->crp_cipher_key, csp->csp_cipher_klen);
		if (error)
			return (error);
	}

	crypto_read_iv(crp, iv);

	if (exf->reinit) {
		/*
		 * xforms that provide a reinit method perform all IV
		 * handling themselves.
		 */
		exf->reinit(sw->sw_kschedule, iv);
	}

	ivp = iv;

	crypto_cursor_init(&cc_in, &crp->crp_buf);
	crypto_cursor_advance(&cc_in, crp->crp_payload_start);
	inlen = crypto_cursor_seglen(&cc_in);
	inblk = crypto_cursor_segbase(&cc_in);