diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2020-08-28 10:05:08 -0700 |
|---|---|---|
| committer | Daniel P. Berrangé <berrange@redhat.com> | 2020-09-10 11:02:23 +0100 |
| commit | eba29771c006d6a689e946fa57334a2ce370c45c (patch) | |
| tree | b2a2a6559e18f89dabbea68cc124875956b7a37d /crypto/cipher-gcrypt.c | |
| parent | ca04c3cf15961e4a01c729a24b00bf804f59ac23 (diff) | |
crypto: Assume blocksize is a power of 2
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.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Diffstat (limited to 'crypto/cipher-gcrypt.c')
| -rw-r--r-- | crypto/cipher-gcrypt.c | 5 |
1 files changed, 3 insertions, 2 deletions
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; |