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[PATCH v2 01/16] crypto: Assume blocksize is a power of 2
From: |
Richard Henderson |
Subject: |
[PATCH v2 01/16] crypto: Assume blocksize is a power of 2 |
Date: |
Fri, 28 Aug 2020 10:05:08 -0700 |
The check in the encode/decode path using full division has a
noticeable amount of overhead. By asserting the blocksize is
a power of 2, we can reduce this check to a mask.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
crypto/cipher-builtin.c | 4 ++--
crypto/cipher-gcrypt.c | 5 +++--
crypto/cipher-nettle.c | 5 +++--
crypto/cipher.c | 1 +
4 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/crypto/cipher-builtin.c b/crypto/cipher-builtin.c
index 35cf7820d9..6eafd39da0 100644
--- a/crypto/cipher-builtin.c
+++ b/crypto/cipher-builtin.c
@@ -484,7 +484,7 @@ qcrypto_builtin_cipher_encrypt(QCryptoCipher *cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
- if (len % ctxt->blocksize) {
+ if (len & (ctxt->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctxt->blocksize);
return -1;
@@ -503,7 +503,7 @@ qcrypto_builtin_cipher_decrypt(QCryptoCipher *cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
- if (len % ctxt->blocksize) {
+ if (len & (ctxt->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctxt->blocksize);
return -1;
diff --git a/crypto/cipher-gcrypt.c b/crypto/cipher-gcrypt.c
index 2864099527..81e4745bff 100644
--- a/crypto/cipher-gcrypt.c
+++ b/crypto/cipher-gcrypt.c
@@ -245,6 +245,7 @@ static QCryptoCipherGcrypt
*qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
g_assert_not_reached();
}
}
+ g_assert(is_power_of_2(ctx->blocksize));
#ifdef CONFIG_QEMU_PRIVATE_XTS
if (mode == QCRYPTO_CIPHER_MODE_XTS) {
@@ -305,7 +306,7 @@ qcrypto_gcrypt_cipher_encrypt(QCryptoCipher *cipher,
QCryptoCipherGcrypt *ctx = cipher->opaque;
gcry_error_t err;
- if (len % ctx->blocksize) {
+ if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
@@ -344,7 +345,7 @@ qcrypto_gcrypt_cipher_decrypt(QCryptoCipher *cipher,
QCryptoCipherGcrypt *ctx = cipher->opaque;
gcry_error_t err;
- if (len % ctx->blocksize) {
+ if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index 7e9a4cc199..0677fdfd33 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -576,6 +576,7 @@ static QCryptoCipherNettle
*qcrypto_cipher_ctx_new(QCryptoCipherAlgorithm alg,
QCryptoCipherAlgorithm_str(alg));
goto error;
}
+ g_assert(is_power_of_2(ctx->blocksize));
if (mode == QCRYPTO_CIPHER_MODE_XTS &&
ctx->blocksize != XTS_BLOCK_SIZE) {
@@ -613,7 +614,7 @@ qcrypto_nettle_cipher_encrypt(QCryptoCipher *cipher,
{
QCryptoCipherNettle *ctx = cipher->opaque;
- if (len % ctx->blocksize) {
+ if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
@@ -666,7 +667,7 @@ qcrypto_nettle_cipher_decrypt(QCryptoCipher *cipher,
{
QCryptoCipherNettle *ctx = cipher->opaque;
- if (len % ctx->blocksize) {
+ if (len & (ctx->blocksize - 1)) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctx->blocksize);
return -1;
diff --git a/crypto/cipher.c b/crypto/cipher.c
index e5adb56271..2722dc7d87 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -19,6 +19,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/host-utils.h"
#include "qapi/error.h"
#include "crypto/cipher.h"
#include "cipherpriv.h"
--
2.25.1
- [PATCH v2 00/16] crypto/cipher: Class hierarchy cleanups, Richard Henderson, 2020/08/28
- [PATCH v2 01/16] crypto: Assume blocksize is a power of 2,
Richard Henderson <=
- [PATCH v2 02/16] crypto: Rename cipher include files to .c.inc, Richard Henderson, 2020/08/28
- [PATCH v2 03/16] crypto: Remove redundant includes, Richard Henderson, 2020/08/28
- [PATCH v2 04/16] crypto/nettle: Fix xts_encrypt arguments, Richard Henderson, 2020/08/28
- [PATCH v2 05/16] crypto: Move QCryptoCipherDriver typedef to crypto/cipher.h, Richard Henderson, 2020/08/28
- [PATCH v2 06/16] crypto: Use the correct const type for driver, Richard Henderson, 2020/08/28
- [PATCH v2 07/16] crypto: Allocate QCryptoCipher with the subclass, Richard Henderson, 2020/08/28
- [PATCH v2 08/16] crypto: Move cipher->driver init to qcrypto_*_cipher_ctx_new, Richard Henderson, 2020/08/28
- [PATCH v2 09/16] crypto: Constify cipher data tables, Richard Henderson, 2020/08/28
- [PATCH v2 10/16] crypto/builtin: Remove odd-sized AES block handling, Richard Henderson, 2020/08/28
- [PATCH v2 11/16] crypto/builtin: Merge qcrypto_cipher_aes_{ecb, xts}_{en, de}crypt, Richard Henderson, 2020/08/28