[qemu.git] / crypto / cipher-gcrypt.c

/*
 * QEMU Crypto cipher libgcrypt algorithms
 *
 * Copyright (c) 2015 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "qemu/osdep.h"
#include <gcrypt.h>


bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
{
    switch (alg) {
    case QCRYPTO_CIPHER_ALG_DES_RFB:
    case QCRYPTO_CIPHER_ALG_AES_128:
    case QCRYPTO_CIPHER_ALG_AES_192:
    case QCRYPTO_CIPHER_ALG_AES_256:
    case QCRYPTO_CIPHER_ALG_CAST5_128:
        return true;
    default:
        return false;
    }
}

typedef struct QCryptoCipherGcrypt QCryptoCipherGcrypt;
struct QCryptoCipherGcrypt {
    gcry_cipher_hd_t handle;
    size_t blocksize;
};

QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
                                  QCryptoCipherMode mode,
                                  const uint8_t *key, size_t nkey,
                                  Error **errp)
{
    QCryptoCipher *cipher;
    QCryptoCipherGcrypt *ctx;
    gcry_error_t err;
    int gcryalg, gcrymode;

    switch (mode) {
    case QCRYPTO_CIPHER_MODE_ECB:
        gcrymode = GCRY_CIPHER_MODE_ECB;
        break;
    case QCRYPTO_CIPHER_MODE_CBC:
        gcrymode = GCRY_CIPHER_MODE_CBC;
        break;
    default:
        error_setg(errp, "Unsupported cipher mode %d", mode);
        return NULL;
    }

    if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
        return NULL;
    }

    switch (alg) {
    case QCRYPTO_CIPHER_ALG_DES_RFB:
        gcryalg = GCRY_CIPHER_DES;
        break;

    case QCRYPTO_CIPHER_ALG_AES_128:
        gcryalg = GCRY_CIPHER_AES128;
        break;

    case QCRYPTO_CIPHER_ALG_AES_192:
        gcryalg = GCRY_CIPHER_AES192;
        break;

    case QCRYPTO_CIPHER_ALG_AES_256:
        gcryalg = GCRY_CIPHER_AES256;
        break;

    case QCRYPTO_CIPHER_ALG_CAST5_128:
        gcryalg = GCRY_CIPHER_CAST5;
        break;

    default:
        error_setg(errp, "Unsupported cipher algorithm %d", alg);
        return NULL;
    }

    cipher = g_new0(QCryptoCipher, 1);
    cipher->alg = alg;
    cipher->mode = mode;

    ctx = g_new0(QCryptoCipherGcrypt, 1);

    err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
    if (err != 0) {
        error_setg(errp, "Cannot initialize cipher: %s",
                   gcry_strerror(err));
        goto error;
    }

    if (cipher->alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
        /* We're using standard DES cipher from gcrypt, so we need
         * to munge the key so that the results are the same as the
         * bizarre RFB variant of DES :-)
         */
        uint8_t *rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
        err = gcry_cipher_setkey(ctx->handle, rfbkey, nkey);
        g_free(rfbkey);
        ctx->blocksize = 8;
    } else {
        err = gcry_cipher_setkey(ctx->handle, key, nkey);
        switch (cipher->alg) {
        case QCRYPTO_CIPHER_ALG_AES_128:
        case QCRYPTO_CIPHER_ALG_AES_192:
        case QCRYPTO_CIPHER_ALG_AES_256:
            ctx->blocksize = 16;
            break;
        case QCRYPTO_CIPHER_ALG_CAST5_128:
            ctx->blocksize = 8;
            break;
        default:
            g_assert_not_reached();
        }
    }
    if (err != 0) {
        error_setg(errp, "Cannot set key: %s",
                   gcry_strerror(err));
        goto error;
    }

    cipher->opaque = ctx;
    return cipher;

 error:
    gcry_cipher_close(ctx->handle);
    g_free(ctx);
    g_free(cipher);
    return NULL;
}


void qcrypto_cipher_free(QCryptoCipher *cipher)
{
    QCryptoCipherGcrypt *ctx;
    if (!cipher) {
        return;
    }
    ctx = cipher->opaque;
    gcry_cipher_close(ctx->handle);
    g_free(ctx);
    g_free(cipher);
}


int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
                           const void *in,
                           void *out,
                           size_t len,
                           Error **errp)
{
    QCryptoCipherGcrypt *ctx = cipher->opaque;
    gcry_error_t err;

    if (len % ctx->blocksize) {
        error_setg(errp, "Length %zu must be a multiple of block size %zu",
                   len, ctx->blocksize);
        return -1;
    }

    err = gcry_cipher_encrypt(ctx->handle,
                              out, len,
                              in, len);
    if (err != 0) {
        error_setg(errp, "Cannot encrypt data: %s",
                   gcry_strerror(err));
        return -1;
    }

    return 0;
}


int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
                           const void *in,
                           void *out,
                           size_t len,
                           Error **errp)
{
    QCryptoCipherGcrypt *ctx = cipher->opaque;
    gcry_error_t err;

    if (len % ctx->blocksize) {
        error_setg(errp, "Length %zu must be a multiple of block size %zu",
                   len, ctx->blocksize);
        return -1;
    }

    err = gcry_cipher_decrypt(ctx->handle,
                              out, len,
                              in, len);
    if (err != 0) {
        error_setg(errp, "Cannot decrypt data: %s",
                   gcry_strerror(err));
        return -1;
    }

    return 0;
}

int qcrypto_cipher_setiv(QCryptoCipher *cipher,
                         const uint8_t *iv, size_t niv,
                         Error **errp)
{
    QCryptoCipherGcrypt *ctx = cipher->opaque;
    gcry_error_t err;

    if (niv != ctx->blocksize) {
        error_setg(errp, "Expected IV size %zu not %zu",
                   ctx->blocksize, niv);
        return -1;
    }

    gcry_cipher_reset(ctx->handle);
    err = gcry_cipher_setiv(ctx->handle, iv, niv);
    if (err != 0) {
        error_setg(errp, "Cannot set IV: %s",
                   gcry_strerror(err));
        return -1;
    }

    return 0;
}
Commit	Line	Data
62893b67 DB	1	/*
	2	* QEMU Crypto cipher libgcrypt algorithms
	3	*
	4	* Copyright (c) 2015 Red Hat, Inc.
	5	*
	6	* This library is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2 of the License, or (at your option) any later version.
	10	*
	11	* This library is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with this library; if not, see <http://www.gnu.org/licenses/>.
	18	*
	19	*/
	20
42f7a448	21	#include "qemu/osdep.h"
62893b67 DB	22	#include <gcrypt.h>
	23
	24
	25	bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
	26	{
	27	switch (alg) {
	28	case QCRYPTO_CIPHER_ALG_DES_RFB:
	29	case QCRYPTO_CIPHER_ALG_AES_128:
	30	case QCRYPTO_CIPHER_ALG_AES_192:
	31	case QCRYPTO_CIPHER_ALG_AES_256:
084a85ee	32	case QCRYPTO_CIPHER_ALG_CAST5_128:
62893b67 DB	33	return true;
	34	default:
	35	return false;
	36	}
	37	}
	38
3a661f1e DB	39	typedef struct QCryptoCipherGcrypt QCryptoCipherGcrypt;
	40	struct QCryptoCipherGcrypt {
	41	gcry_cipher_hd_t handle;
	42	size_t blocksize;
	43	};
62893b67 DB	44
	45	QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
	46	QCryptoCipherMode mode,
	47	const uint8_t *key, size_t nkey,
	48	Error **errp)
	49	{
	50	QCryptoCipher *cipher;
3a661f1e	51	QCryptoCipherGcrypt *ctx;
62893b67 DB	52	gcry_error_t err;
	53	int gcryalg, gcrymode;
	54
	55	switch (mode) {
	56	case QCRYPTO_CIPHER_MODE_ECB:
	57	gcrymode = GCRY_CIPHER_MODE_ECB;
	58	break;
	59	case QCRYPTO_CIPHER_MODE_CBC:
	60	gcrymode = GCRY_CIPHER_MODE_CBC;
	61	break;
	62	default:
	63	error_setg(errp, "Unsupported cipher mode %d", mode);
	64	return NULL;
	65	}
	66
	67	if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
	68	return NULL;
	69	}
	70
	71	switch (alg) {
	72	case QCRYPTO_CIPHER_ALG_DES_RFB:
	73	gcryalg = GCRY_CIPHER_DES;
	74	break;
	75
	76	case QCRYPTO_CIPHER_ALG_AES_128:
	77	gcryalg = GCRY_CIPHER_AES128;
	78	break;
	79
	80	case QCRYPTO_CIPHER_ALG_AES_192:
	81	gcryalg = GCRY_CIPHER_AES192;
	82	break;
	83
	84	case QCRYPTO_CIPHER_ALG_AES_256:
	85	gcryalg = GCRY_CIPHER_AES256;
	86	break;
	87
084a85ee DB	88	case QCRYPTO_CIPHER_ALG_CAST5_128:
	89	gcryalg = GCRY_CIPHER_CAST5;
	90	break;
	91
62893b67 DB	92	default:
	93	error_setg(errp, "Unsupported cipher algorithm %d", alg);
	94	return NULL;
	95	}
	96
	97	cipher = g_new0(QCryptoCipher, 1);
	98	cipher->alg = alg;
	99	cipher->mode = mode;
	100
3a661f1e DB	101	ctx = g_new0(QCryptoCipherGcrypt, 1);
	102
	103	err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
62893b67 DB	104	if (err != 0) {
	105	error_setg(errp, "Cannot initialize cipher: %s",
	106	gcry_strerror(err));
	107	goto error;
	108	}
	109
	110	if (cipher->alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
	111	/* We're using standard DES cipher from gcrypt, so we need
	112	* to munge the key so that the results are the same as the
	113	* bizarre RFB variant of DES :-)
	114	*/
	115	uint8_t *rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
3a661f1e	116	err = gcry_cipher_setkey(ctx->handle, rfbkey, nkey);
62893b67	117	g_free(rfbkey);
3a661f1e	118	ctx->blocksize = 8;
62893b67	119	} else {
3a661f1e	120	err = gcry_cipher_setkey(ctx->handle, key, nkey);
084a85ee DB	121	switch (cipher->alg) {
	122	case QCRYPTO_CIPHER_ALG_AES_128:
	123	case QCRYPTO_CIPHER_ALG_AES_192:
	124	case QCRYPTO_CIPHER_ALG_AES_256:
	125	ctx->blocksize = 16;
	126	break;
	127	case QCRYPTO_CIPHER_ALG_CAST5_128:
	128	ctx->blocksize = 8;
	129	break;
	130	default:
	131	g_assert_not_reached();
	132	}
62893b67 DB	133	}
	134	if (err != 0) {
	135	error_setg(errp, "Cannot set key: %s",
	136	gcry_strerror(err));
	137	goto error;
	138	}
	139
3a661f1e	140	cipher->opaque = ctx;
62893b67 DB	141	return cipher;
	142
	143	error:
3a661f1e DB	144	gcry_cipher_close(ctx->handle);
3a661f1e DB	145	g_free(ctx);
62893b67 DB	146	g_free(cipher);
	147	return NULL;
	148	}
	149
	150
	151	void qcrypto_cipher_free(QCryptoCipher *cipher)
	152	{
3a661f1e	153	QCryptoCipherGcrypt *ctx;
62893b67 DB	154	if (!cipher) {
	155	return;
	156	}
3a661f1e DB	157	ctx = cipher->opaque;
	158	gcry_cipher_close(ctx->handle);
	159	g_free(ctx);
62893b67 DB	160	g_free(cipher);
	161	}
	162
	163
	164	int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
	165	const void *in,
	166	void *out,
	167	size_t len,
	168	Error **errp)
	169	{
3a661f1e	170	QCryptoCipherGcrypt *ctx = cipher->opaque;
62893b67 DB	171	gcry_error_t err;
62893b67 DB	172
3a661f1e DB	173	if (len % ctx->blocksize) {
	174	error_setg(errp, "Length %zu must be a multiple of block size %zu",
	175	len, ctx->blocksize);
	176	return -1;
	177	}
	178
	179	err = gcry_cipher_encrypt(ctx->handle,
62893b67 DB	180	out, len,
	181	in, len);
	182	if (err != 0) {
	183	error_setg(errp, "Cannot encrypt data: %s",
	184	gcry_strerror(err));
	185	return -1;
	186	}
	187
	188	return 0;
	189	}
	190
	191
	192	int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
	193	const void *in,
	194	void *out,
	195	size_t len,
	196	Error **errp)
	197	{
3a661f1e	198	QCryptoCipherGcrypt *ctx = cipher->opaque;
62893b67 DB	199	gcry_error_t err;
62893b67 DB	200
3a661f1e DB	201	if (len % ctx->blocksize) {
	202	error_setg(errp, "Length %zu must be a multiple of block size %zu",
	203	len, ctx->blocksize);
	204	return -1;
	205	}
	206
	207	err = gcry_cipher_decrypt(ctx->handle,
62893b67 DB	208	out, len,
	209	in, len);
	210	if (err != 0) {
	211	error_setg(errp, "Cannot decrypt data: %s",
	212	gcry_strerror(err));
	213	return -1;
	214	}
	215
	216	return 0;
	217	}
	218
	219	int qcrypto_cipher_setiv(QCryptoCipher *cipher,
	220	const uint8_t *iv, size_t niv,
	221	Error **errp)
	222	{
3a661f1e	223	QCryptoCipherGcrypt *ctx = cipher->opaque;
62893b67 DB	224	gcry_error_t err;
62893b67 DB	225
3a661f1e DB	226	if (niv != ctx->blocksize) {
	227	error_setg(errp, "Expected IV size %zu not %zu",
	228	ctx->blocksize, niv);
	229	return -1;
	230	}
	231
	232	gcry_cipher_reset(ctx->handle);
	233	err = gcry_cipher_setiv(ctx->handle, iv, niv);
62893b67 DB	234	if (err != 0) {
	235	error_setg(errp, "Cannot set IV: %s",
	236	gcry_strerror(err));
	237	return -1;
	238	}
	239
	240	return 0;
	241	}