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| 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-nettle.c | |
| parent | ca04c3cf15961e4a01c729a24b00bf804f59ac23 (diff) | |
| download | focaccia-qemu-eba29771c006d6a689e946fa57334a2ce370c45c.tar.gz focaccia-qemu-eba29771c006d6a689e946fa57334a2ce370c45c.zip | |
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-nettle.c')
| -rw-r--r-- | crypto/cipher-nettle.c | 5 |
1 files changed, 3 insertions, 2 deletions
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; |