From 6801404429d51b260e08c6ad54dbf3ac430016db Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Fri, 2 Jul 2021 17:00:32 +0100 Subject: [PATCH] crypto: delete built-in XTS cipher mode support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The built-in AES+XTS implementation is used for the LUKS encryption When building system emulators it is reasonable to expect that an external crypto library is being used instead. The performance of the builtin XTS implementation is terrible as it has no CPU acceleration support. It is thus not worth keeping a home grown XTS implementation for the built-in cipher backend. Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrangé --- crypto/cipher-builtin.c.inc | 60 ------------------------------------- crypto/meson.build | 6 ++-- meson.build | 7 ++--- 3 files changed, 6 insertions(+), 67 deletions(-) diff --git a/crypto/cipher-builtin.c.inc b/crypto/cipher-builtin.c.inc index 70743f253c..b409089095 100644 --- a/crypto/cipher-builtin.c.inc +++ b/crypto/cipher-builtin.c.inc @@ -19,7 +19,6 @@ */ #include "crypto/aes.h" -#include "crypto/xts.h" typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext; struct QCryptoCipherBuiltinAESContext { @@ -31,7 +30,6 @@ typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES; struct QCryptoCipherBuiltinAES { QCryptoCipher base; QCryptoCipherBuiltinAESContext key; - QCryptoCipherBuiltinAESContext key_tweak; uint8_t iv[AES_BLOCK_SIZE]; }; @@ -193,39 +191,6 @@ static int qcrypto_cipher_aes_decrypt_cbc(QCryptoCipher *cipher, return 0; } -static int qcrypto_cipher_aes_encrypt_xts(QCryptoCipher *cipher, - const void *in, void *out, - size_t len, Error **errp) -{ - QCryptoCipherBuiltinAES *ctx - = container_of(cipher, QCryptoCipherBuiltinAES, base); - - if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { - return -1; - } - xts_encrypt(&ctx->key, &ctx->key_tweak, - do_aes_encrypt_ecb, do_aes_decrypt_ecb, - ctx->iv, len, out, in); - return 0; -} - -static int qcrypto_cipher_aes_decrypt_xts(QCryptoCipher *cipher, - const void *in, void *out, - size_t len, Error **errp) -{ - QCryptoCipherBuiltinAES *ctx - = container_of(cipher, QCryptoCipherBuiltinAES, base); - - if (!qcrypto_length_check(len, AES_BLOCK_SIZE, errp)) { - return -1; - } - xts_decrypt(&ctx->key, &ctx->key_tweak, - do_aes_encrypt_ecb, do_aes_decrypt_ecb, - ctx->iv, len, out, in); - return 0; -} - - static int qcrypto_cipher_aes_setiv(QCryptoCipher *cipher, const uint8_t *iv, size_t niv, Error **errp) { @@ -256,14 +221,6 @@ static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_cbc = { .cipher_free = qcrypto_cipher_ctx_free, }; -static const struct QCryptoCipherDriver qcrypto_cipher_aes_driver_xts = { - .cipher_encrypt = qcrypto_cipher_aes_encrypt_xts, - .cipher_decrypt = qcrypto_cipher_aes_decrypt_xts, - .cipher_setiv = qcrypto_cipher_aes_setiv, - .cipher_free = qcrypto_cipher_ctx_free, -}; - - bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg, QCryptoCipherMode mode) { @@ -274,7 +231,6 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg, switch (mode) { case QCRYPTO_CIPHER_MODE_ECB: case QCRYPTO_CIPHER_MODE_CBC: - case QCRYPTO_CIPHER_MODE_XTS: return true; default: return false; @@ -310,9 +266,6 @@ static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg, case QCRYPTO_CIPHER_MODE_CBC: drv = &qcrypto_cipher_aes_driver_cbc; break; - case QCRYPTO_CIPHER_MODE_XTS: - drv = &qcrypto_cipher_aes_driver_xts; - break; default: goto bad_mode; } @@ -320,19 +273,6 @@ static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg, ctx = g_new0(QCryptoCipherBuiltinAES, 1); ctx->base.driver = drv; - if (mode == QCRYPTO_CIPHER_MODE_XTS) { - nkey /= 2; - if (AES_set_encrypt_key(key + nkey, nkey * 8, - &ctx->key_tweak.enc)) { - error_setg(errp, "Failed to set encryption key"); - goto error; - } - if (AES_set_decrypt_key(key + nkey, nkey * 8, - &ctx->key_tweak.dec)) { - error_setg(errp, "Failed to set decryption key"); - goto error; - } - } if (AES_set_encrypt_key(key, nkey * 8, &ctx->key.enc)) { error_setg(errp, "Failed to set encryption key"); goto error; diff --git a/crypto/meson.build b/crypto/meson.build index b384ca8b57..fc8de287e1 100644 --- a/crypto/meson.build +++ b/crypto/meson.build @@ -23,14 +23,14 @@ crypto_ss.add(files( if nettle.found() crypto_ss.add(nettle, files('hash-nettle.c', 'hmac-nettle.c', 'pbkdf-nettle.c')) + if xts == 'private' + crypto_ss.add(files('xts.c')) + endif elif gcrypt.found() crypto_ss.add(gcrypt, files('hash-gcrypt.c', 'hmac-gcrypt.c', 'pbkdf-gcrypt.c')) else crypto_ss.add(files('hash-glib.c', 'hmac-glib.c', 'pbkdf-stub.c')) endif -if xts == 'private' - crypto_ss.add(files('xts.c')) -endif crypto_ss.add(when: 'CONFIG_SECRET_KEYRING', if_true: files('secret_keyring.c')) crypto_ss.add(when: 'CONFIG_AF_ALG', if_true: files('afalg.c', 'cipher-afalg.c', 'hash-afalg.c')) diff --git a/meson.build b/meson.build index a96c8b858c..8f899e1e9b 100644 --- a/meson.build +++ b/meson.build @@ -826,7 +826,7 @@ endif # Nettle has priority over gcrypt gcrypt = not_found nettle = not_found -xts = 'private' +xts = 'none' if get_option('nettle').enabled() and get_option('gcrypt').enabled() error('Only one of gcrypt & nettle can be enabled') elif (not get_option('nettle').auto() or have_system) and not get_option('gcrypt').enabled() @@ -834,8 +834,8 @@ elif (not get_option('nettle').auto() or have_system) and not get_option('gcrypt method: 'pkg-config', required: get_option('nettle'), kwargs: static_kwargs) - if nettle.found() and cc.has_header('nettle/xts.h', dependencies: nettle) - xts = 'nettle' + if nettle.found() and not cc.has_header('nettle/xts.h', dependencies: nettle) + xts = 'private' endif endif if (not get_option('gcrypt').auto() or have_system) and not nettle.found() @@ -843,7 +843,6 @@ if (not get_option('gcrypt').auto() or have_system) and not nettle.found() method: 'config-tool', required: get_option('gcrypt'), kwargs: static_kwargs) - xts = 'gcrypt' # Debian has removed -lgpg-error from libgcrypt-config # as it "spreads unnecessary dependencies" which in # turn breaks static builds...