diff --git a/crypto/cipher-gnutls.c.inc b/crypto/cipher-gnutls.c.inc new file mode 100644 index 0000000000..501e4e07a5 --- /dev/null +++ b/crypto/cipher-gnutls.c.inc @@ -0,0 +1,335 @@ +/* + * QEMU Crypto cipher gnutls algorithms + * + * Copyright (c) 2021 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 2.1 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 . + * + */ + +#include "qemu/osdep.h" +#include "cipherpriv.h" + +#include + +#if GNUTLS_VERSION_NUMBER >= 0x030608 +#define QEMU_GNUTLS_XTS +#endif + +bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg, + QCryptoCipherMode mode) +{ + + switch (mode) { + case QCRYPTO_CIPHER_MODE_ECB: + case QCRYPTO_CIPHER_MODE_CBC: + switch (alg) { + case QCRYPTO_CIPHER_ALG_AES_128: + case QCRYPTO_CIPHER_ALG_AES_192: + case QCRYPTO_CIPHER_ALG_AES_256: + case QCRYPTO_CIPHER_ALG_DES: + case QCRYPTO_CIPHER_ALG_3DES: + return true; + default: + return false; + } +#ifdef QEMU_GNUTLS_XTS + case QCRYPTO_CIPHER_MODE_XTS: + switch (alg) { + case QCRYPTO_CIPHER_ALG_AES_128: + case QCRYPTO_CIPHER_ALG_AES_256: + return true; + default: + return false; + } +#endif + default: + return false; + } +} + +typedef struct QCryptoCipherGnutls QCryptoCipherGnutls; +struct QCryptoCipherGnutls { + QCryptoCipher base; + gnutls_cipher_hd_t handle; /* XTS & CBC mode */ + gnutls_cipher_algorithm_t galg; /* ECB mode */ + guint8 *key; /* ECB mode */ + size_t nkey; /* ECB mode */ + size_t blocksize; +}; + + +static void +qcrypto_gnutls_cipher_free(QCryptoCipher *cipher) +{ + QCryptoCipherGnutls *ctx = container_of(cipher, QCryptoCipherGnutls, base); + + g_free(ctx->key); + if (ctx->handle) { + gnutls_cipher_deinit(ctx->handle); + } + g_free(ctx); +} + + +static int +qcrypto_gnutls_cipher_encrypt(QCryptoCipher *cipher, + const void *in, + void *out, + size_t len, + Error **errp) +{ + QCryptoCipherGnutls *ctx = container_of(cipher, QCryptoCipherGnutls, base); + int err; + + if (len % ctx->blocksize) { + error_setg(errp, "Length %zu must be a multiple of block size %zu", + len, ctx->blocksize); + return -1; + } + + if (ctx->handle) { /* CBC / XTS mode */ + err = gnutls_cipher_encrypt2(ctx->handle, + in, len, + out, len); + if (err != 0) { + error_setg(errp, "Cannot encrypt data: %s", + gnutls_strerror(err)); + return -1; + } + } else { /* ECB mode very inefficiently faked with CBC */ + g_autofree unsigned char *iv = g_new0(unsigned char, ctx->blocksize); + while (len) { + gnutls_cipher_hd_t handle; + gnutls_datum_t gkey = { (unsigned char *)ctx->key, ctx->nkey }; + int err = gnutls_cipher_init(&handle, ctx->galg, &gkey, NULL); + if (err != 0) { + error_setg(errp, "Cannot initialize cipher: %s", + gnutls_strerror(err)); + return -1; + } + + gnutls_cipher_set_iv(handle, iv, ctx->blocksize); + + err = gnutls_cipher_encrypt2(handle, + in, ctx->blocksize, + out, ctx->blocksize); + if (err != 0) { + gnutls_cipher_deinit(handle); + error_setg(errp, "Cannot encrypt data: %s", + gnutls_strerror(err)); + return -1; + } + gnutls_cipher_deinit(handle); + + len -= ctx->blocksize; + in += ctx->blocksize; + out += ctx->blocksize; + } + } + + return 0; +} + + +static int +qcrypto_gnutls_cipher_decrypt(QCryptoCipher *cipher, + const void *in, + void *out, + size_t len, + Error **errp) +{ + QCryptoCipherGnutls *ctx = container_of(cipher, QCryptoCipherGnutls, base); + int err; + + if (len % ctx->blocksize) { + error_setg(errp, "Length %zu must be a multiple of block size %zu", + len, ctx->blocksize); + return -1; + } + + if (ctx->handle) { /* CBC / XTS mode */ + err = gnutls_cipher_decrypt2(ctx->handle, + in, len, + out, len); + + if (err != 0) { + error_setg(errp, "Cannot decrypt data: %s", + gnutls_strerror(err)); + return -1; + } + } else { /* ECB mode very inefficiently faked with CBC */ + g_autofree unsigned char *iv = g_new0(unsigned char, ctx->blocksize); + while (len) { + gnutls_cipher_hd_t handle; + gnutls_datum_t gkey = { (unsigned char *)ctx->key, ctx->nkey }; + int err = gnutls_cipher_init(&handle, ctx->galg, &gkey, NULL); + if (err != 0) { + error_setg(errp, "Cannot initialize cipher: %s", + gnutls_strerror(err)); + return -1; + } + + gnutls_cipher_set_iv(handle, iv, ctx->blocksize); + + err = gnutls_cipher_decrypt2(handle, + in, ctx->blocksize, + out, ctx->blocksize); + if (err != 0) { + gnutls_cipher_deinit(handle); + error_setg(errp, "Cannot encrypt data: %s", + gnutls_strerror(err)); + return -1; + } + gnutls_cipher_deinit(handle); + + len -= ctx->blocksize; + in += ctx->blocksize; + out += ctx->blocksize; + } + } + + return 0; +} + +static int +qcrypto_gnutls_cipher_setiv(QCryptoCipher *cipher, + const uint8_t *iv, size_t niv, + Error **errp) +{ + QCryptoCipherGnutls *ctx = container_of(cipher, QCryptoCipherGnutls, base); + + if (niv != ctx->blocksize) { + error_setg(errp, "Expected IV size %zu not %zu", + ctx->blocksize, niv); + return -1; + } + + gnutls_cipher_set_iv(ctx->handle, (unsigned char *)iv, niv); + + return 0; +} + + +static struct QCryptoCipherDriver gnutls_driver = { + .cipher_encrypt = qcrypto_gnutls_cipher_encrypt, + .cipher_decrypt = qcrypto_gnutls_cipher_decrypt, + .cipher_setiv = qcrypto_gnutls_cipher_setiv, + .cipher_free = qcrypto_gnutls_cipher_free, +}; + +static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg, + QCryptoCipherMode mode, + const uint8_t *key, + size_t nkey, + Error **errp) +{ + QCryptoCipherGnutls *ctx; + gnutls_datum_t gkey = { (unsigned char *)key, nkey }; + gnutls_cipher_algorithm_t galg = GNUTLS_CIPHER_UNKNOWN; + int err; + + switch (mode) { +#ifdef QEMU_GNUTLS_XTS + case QCRYPTO_CIPHER_MODE_XTS: + switch (alg) { + case QCRYPTO_CIPHER_ALG_AES_128: + galg = GNUTLS_CIPHER_AES_128_XTS; + break; + case QCRYPTO_CIPHER_ALG_AES_256: + galg = GNUTLS_CIPHER_AES_256_XTS; + break; + default: + break; + } + break; +#endif + + case QCRYPTO_CIPHER_MODE_ECB: + case QCRYPTO_CIPHER_MODE_CBC: + switch (alg) { + case QCRYPTO_CIPHER_ALG_AES_128: + galg = GNUTLS_CIPHER_AES_128_CBC; + break; + case QCRYPTO_CIPHER_ALG_AES_192: + galg = GNUTLS_CIPHER_AES_192_CBC; + break; + case QCRYPTO_CIPHER_ALG_AES_256: + galg = GNUTLS_CIPHER_AES_256_CBC; + break; + case QCRYPTO_CIPHER_ALG_DES: + galg = GNUTLS_CIPHER_DES_CBC; + break; + case QCRYPTO_CIPHER_ALG_3DES: + galg = GNUTLS_CIPHER_3DES_CBC; + break; + default: + break; + } + break; + default: + break; + } + + if (galg == GNUTLS_CIPHER_UNKNOWN) { + error_setg(errp, "Unsupported cipher algorithm %s with %s mode", + QCryptoCipherAlgorithm_str(alg), + QCryptoCipherMode_str(mode)); + return NULL; + } + + if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) { + return NULL; + } + + ctx = g_new0(QCryptoCipherGnutls, 1); + ctx->base.driver = &gnutls_driver; + + if (mode == QCRYPTO_CIPHER_MODE_ECB) { + ctx->key = g_new0(guint8, nkey); + memcpy(ctx->key, key, nkey); + ctx->nkey = nkey; + ctx->galg = galg; + } else { + err = gnutls_cipher_init(&ctx->handle, galg, &gkey, NULL); + if (err != 0) { + error_setg(errp, "Cannot initialize cipher: %s", + gnutls_strerror(err)); + goto error; + } + } + + if (alg == QCRYPTO_CIPHER_ALG_DES || + alg == QCRYPTO_CIPHER_ALG_3DES) + ctx->blocksize = 8; + else + ctx->blocksize = 16; + + /* + * Our API contract for requires iv to be optional + * but nettle gets unhappy when called by gnutls + * in this case, so we just force set a default + * all-zeros IV, to match behaviour of other backends. + */ + if (mode != QCRYPTO_CIPHER_MODE_ECB) { + g_autofree unsigned char *iv = g_new0(unsigned char, ctx->blocksize); + gnutls_cipher_set_iv(ctx->handle, iv, ctx->blocksize); + } + + return &ctx->base; + + error: + qcrypto_gnutls_cipher_free(&ctx->base); + return NULL; +} diff --git a/crypto/cipher.c b/crypto/cipher.c index 1f5528be49..74b09a5b26 100644 --- a/crypto/cipher.c +++ b/crypto/cipher.c @@ -136,6 +136,8 @@ qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg, #include "cipher-gcrypt.c.inc" #elif defined CONFIG_NETTLE #include "cipher-nettle.c.inc" +#elif defined CONFIG_GNUTLS_CRYPTO +#include "cipher-gnutls.c.inc" #else #include "cipher-builtin.c.inc" #endif