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![Daniel P. Berrangé](/assets/img/avatar_default.png)
Currently the crypto layer exposes support for a 'des-rfb' algorithm which is just normal single-DES, with the bits in each key byte reversed. This special key munging is required by the RFB protocol password authentication mechanism. Since the crypto layer is generic shared code, it makes more sense to do the key byte munging in the VNC server code, and expose normal single-DES support. Replacing cipher 'des-rfb' by 'des' looks like an incompatible interface change, but it doesn't matter. While the QMP schema allows any QCryptoCipherAlgorithm for the 'cipher-alg' field in QCryptoBlockCreateOptionsLUKS, the code restricts what can be used at runtime. Thus the only effect is a change in error message. Original behaviour: $ qemu-img create -f luks --object secret,id=sec0,data=123 -o cipher-alg=des-rfb,key-secret=sec0 demo.luks 1G Formatting 'demo.luks', fmt=luks size=1073741824 key-secret=sec0 cipher-alg=des-rfb qemu-img: demo.luks: Algorithm 'des-rfb' not supported New behaviour: $ qemu-img create -f luks --object secret,id=sec0,data=123 -o cipher-alg=des-rfb,key-secret=sec0 demo.luks 1G Formatting 'demo.luks', fmt=luks size=1073741824 key-secret=sec0 cipher-alg=des-fish qemu-img: demo.luks: Invalid parameter 'des-rfb' Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
273 lines
7.8 KiB
C++
273 lines
7.8 KiB
C++
/*
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* QEMU Crypto cipher libgcrypt algorithms
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <gcrypt.h>
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bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode)
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{
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switch (alg) {
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case QCRYPTO_CIPHER_ALG_DES:
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case QCRYPTO_CIPHER_ALG_3DES:
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case QCRYPTO_CIPHER_ALG_AES_128:
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case QCRYPTO_CIPHER_ALG_AES_192:
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case QCRYPTO_CIPHER_ALG_AES_256:
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case QCRYPTO_CIPHER_ALG_CAST5_128:
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case QCRYPTO_CIPHER_ALG_SERPENT_128:
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case QCRYPTO_CIPHER_ALG_SERPENT_192:
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case QCRYPTO_CIPHER_ALG_SERPENT_256:
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case QCRYPTO_CIPHER_ALG_TWOFISH_128:
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case QCRYPTO_CIPHER_ALG_TWOFISH_256:
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break;
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default:
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return false;
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}
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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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case QCRYPTO_CIPHER_MODE_CBC:
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case QCRYPTO_CIPHER_MODE_XTS:
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case QCRYPTO_CIPHER_MODE_CTR:
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return true;
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default:
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return false;
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}
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}
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typedef struct QCryptoCipherGcrypt {
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QCryptoCipher base;
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gcry_cipher_hd_t handle;
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size_t blocksize;
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} QCryptoCipherGcrypt;
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static void qcrypto_gcrypt_ctx_free(QCryptoCipher *cipher)
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{
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QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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gcry_cipher_close(ctx->handle);
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g_free(ctx);
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}
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static int qcrypto_gcrypt_encrypt(QCryptoCipher *cipher, const void *in,
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void *out, size_t len, Error **errp)
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{
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QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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gcry_error_t err;
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if (len & (ctx->blocksize - 1)) {
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error_setg(errp, "Length %zu must be a multiple of block size %zu",
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len, ctx->blocksize);
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return -1;
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}
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err = gcry_cipher_encrypt(ctx->handle, out, len, in, len);
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if (err != 0) {
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error_setg(errp, "Cannot encrypt data: %s", gcry_strerror(err));
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return -1;
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}
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return 0;
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}
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static int qcrypto_gcrypt_decrypt(QCryptoCipher *cipher, const void *in,
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void *out, size_t len, Error **errp)
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{
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QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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gcry_error_t err;
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if (len & (ctx->blocksize - 1)) {
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error_setg(errp, "Length %zu must be a multiple of block size %zu",
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len, ctx->blocksize);
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return -1;
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}
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err = gcry_cipher_decrypt(ctx->handle, out, len, in, len);
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if (err != 0) {
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error_setg(errp, "Cannot decrypt data: %s",
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gcry_strerror(err));
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return -1;
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}
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return 0;
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}
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static int qcrypto_gcrypt_setiv(QCryptoCipher *cipher,
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const uint8_t *iv, size_t niv,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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gcry_error_t err;
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if (niv != ctx->blocksize) {
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error_setg(errp, "Expected IV size %zu not %zu",
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ctx->blocksize, niv);
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return -1;
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}
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gcry_cipher_reset(ctx->handle);
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err = gcry_cipher_setiv(ctx->handle, iv, niv);
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if (err != 0) {
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error_setg(errp, "Cannot set IV: %s", gcry_strerror(err));
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return -1;
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}
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return 0;
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}
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static int qcrypto_gcrypt_ctr_setiv(QCryptoCipher *cipher,
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const uint8_t *iv, size_t niv,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base);
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gcry_error_t err;
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if (niv != ctx->blocksize) {
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error_setg(errp, "Expected IV size %zu not %zu",
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ctx->blocksize, niv);
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return -1;
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}
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err = gcry_cipher_setctr(ctx->handle, iv, niv);
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if (err != 0) {
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error_setg(errp, "Cannot set Counter: %s", gcry_strerror(err));
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return -1;
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}
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return 0;
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}
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static const struct QCryptoCipherDriver qcrypto_gcrypt_driver = {
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.cipher_encrypt = qcrypto_gcrypt_encrypt,
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.cipher_decrypt = qcrypto_gcrypt_decrypt,
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.cipher_setiv = qcrypto_gcrypt_setiv,
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.cipher_free = qcrypto_gcrypt_ctx_free,
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};
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static const struct QCryptoCipherDriver qcrypto_gcrypt_ctr_driver = {
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.cipher_encrypt = qcrypto_gcrypt_encrypt,
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.cipher_decrypt = qcrypto_gcrypt_decrypt,
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.cipher_setiv = qcrypto_gcrypt_ctr_setiv,
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.cipher_free = qcrypto_gcrypt_ctx_free,
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};
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static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode,
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const uint8_t *key,
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size_t nkey,
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Error **errp)
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{
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QCryptoCipherGcrypt *ctx;
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const QCryptoCipherDriver *drv;
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gcry_error_t err;
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int gcryalg, gcrymode;
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if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) {
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return NULL;
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}
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switch (alg) {
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case QCRYPTO_CIPHER_ALG_DES:
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gcryalg = GCRY_CIPHER_DES;
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break;
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case QCRYPTO_CIPHER_ALG_3DES:
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gcryalg = GCRY_CIPHER_3DES;
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break;
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case QCRYPTO_CIPHER_ALG_AES_128:
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gcryalg = GCRY_CIPHER_AES128;
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break;
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case QCRYPTO_CIPHER_ALG_AES_192:
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gcryalg = GCRY_CIPHER_AES192;
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break;
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case QCRYPTO_CIPHER_ALG_AES_256:
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gcryalg = GCRY_CIPHER_AES256;
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break;
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case QCRYPTO_CIPHER_ALG_CAST5_128:
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gcryalg = GCRY_CIPHER_CAST5;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_128:
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gcryalg = GCRY_CIPHER_SERPENT128;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_192:
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gcryalg = GCRY_CIPHER_SERPENT192;
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break;
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case QCRYPTO_CIPHER_ALG_SERPENT_256:
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gcryalg = GCRY_CIPHER_SERPENT256;
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break;
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case QCRYPTO_CIPHER_ALG_TWOFISH_128:
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gcryalg = GCRY_CIPHER_TWOFISH128;
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break;
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case QCRYPTO_CIPHER_ALG_TWOFISH_256:
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gcryalg = GCRY_CIPHER_TWOFISH;
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break;
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default:
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error_setg(errp, "Unsupported cipher algorithm %s",
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QCryptoCipherAlgorithm_str(alg));
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return NULL;
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}
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drv = &qcrypto_gcrypt_driver;
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switch (mode) {
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case QCRYPTO_CIPHER_MODE_ECB:
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gcrymode = GCRY_CIPHER_MODE_ECB;
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break;
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case QCRYPTO_CIPHER_MODE_XTS:
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gcrymode = GCRY_CIPHER_MODE_XTS;
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break;
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case QCRYPTO_CIPHER_MODE_CBC:
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gcrymode = GCRY_CIPHER_MODE_CBC;
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break;
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case QCRYPTO_CIPHER_MODE_CTR:
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drv = &qcrypto_gcrypt_ctr_driver;
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gcrymode = GCRY_CIPHER_MODE_CTR;
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break;
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default:
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error_setg(errp, "Unsupported cipher mode %s",
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QCryptoCipherMode_str(mode));
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return NULL;
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}
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ctx = g_new0(QCryptoCipherGcrypt, 1);
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ctx->base.driver = drv;
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err = gcry_cipher_open(&ctx->handle, gcryalg, gcrymode, 0);
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if (err != 0) {
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error_setg(errp, "Cannot initialize cipher: %s",
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gcry_strerror(err));
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goto error;
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}
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ctx->blocksize = gcry_cipher_get_algo_blklen(gcryalg);
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err = gcry_cipher_setkey(ctx->handle, key, nkey);
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if (err != 0) {
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error_setg(errp, "Cannot set key: %s", gcry_strerror(err));
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goto error;
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}
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return &ctx->base;
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error:
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gcry_cipher_close(ctx->handle);
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g_free(ctx);
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return NULL;
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}
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