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[Qemu-devel] [PULL v2 10/13] crypto: refactor code for dealing with AES
From: |
Daniel P. Berrange |
Subject: |
[Qemu-devel] [PULL v2 10/13] crypto: refactor code for dealing with AES cipher |
Date: |
Thu, 17 Mar 2016 14:43:53 +0000 |
The built-in and nettle cipher backends for AES maintain
two separate AES contexts, one for encryption and one for
decryption. This is going to be inconvenient for the future
code dealing with XTS, so wrap them up in a single struct
so there is just one pointer to pass around for both
encryption and decryption.
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Daniel P. Berrange <address@hidden>
---
crypto/cipher-builtin.c | 126 ++++++++++++++++++++++++++++++------------------
crypto/cipher-nettle.c | 57 +++++++++++-----------
2 files changed, 109 insertions(+), 74 deletions(-)
diff --git a/crypto/cipher-builtin.c b/crypto/cipher-builtin.c
index 138b7a0..836ed1a 100644
--- a/crypto/cipher-builtin.c
+++ b/crypto/cipher-builtin.c
@@ -22,10 +22,14 @@
#include "crypto/aes.h"
#include "crypto/desrfb.h"
+typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext;
+struct QCryptoCipherBuiltinAESContext {
+ AES_KEY enc;
+ AES_KEY dec;
+};
typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES;
struct QCryptoCipherBuiltinAES {
- AES_KEY encrypt_key;
- AES_KEY decrypt_key;
+ QCryptoCipherBuiltinAESContext key;
uint8_t iv[AES_BLOCK_SIZE];
};
typedef struct QCryptoCipherBuiltinDESRFB QCryptoCipherBuiltinDESRFB;
@@ -67,6 +71,58 @@ static void qcrypto_cipher_free_aes(QCryptoCipher *cipher)
}
+static void qcrypto_cipher_aes_ecb_encrypt(AES_KEY *key,
+ const void *in,
+ void *out,
+ size_t len)
+{
+ const uint8_t *inptr = in;
+ uint8_t *outptr = out;
+ while (len) {
+ if (len > AES_BLOCK_SIZE) {
+ AES_encrypt(inptr, outptr, key);
+ inptr += AES_BLOCK_SIZE;
+ outptr += AES_BLOCK_SIZE;
+ len -= AES_BLOCK_SIZE;
+ } else {
+ uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
+ memcpy(tmp1, inptr, len);
+ /* Fill with 0 to avoid valgrind uninitialized reads */
+ memset(tmp1 + len, 0, sizeof(tmp1) - len);
+ AES_encrypt(tmp1, tmp2, key);
+ memcpy(outptr, tmp2, len);
+ len = 0;
+ }
+ }
+}
+
+
+static void qcrypto_cipher_aes_ecb_decrypt(AES_KEY *key,
+ const void *in,
+ void *out,
+ size_t len)
+{
+ const uint8_t *inptr = in;
+ uint8_t *outptr = out;
+ while (len) {
+ if (len > AES_BLOCK_SIZE) {
+ AES_decrypt(inptr, outptr, key);
+ inptr += AES_BLOCK_SIZE;
+ outptr += AES_BLOCK_SIZE;
+ len -= AES_BLOCK_SIZE;
+ } else {
+ uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
+ memcpy(tmp1, inptr, len);
+ /* Fill with 0 to avoid valgrind uninitialized reads */
+ memset(tmp1 + len, 0, sizeof(tmp1) - len);
+ AES_decrypt(tmp1, tmp2, key);
+ memcpy(outptr, tmp2, len);
+ len = 0;
+ }
+ }
+}
+
+
static int qcrypto_cipher_encrypt_aes(QCryptoCipher *cipher,
const void *in,
void *out,
@@ -75,29 +131,18 @@ static int qcrypto_cipher_encrypt_aes(QCryptoCipher
*cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
- if (cipher->mode == QCRYPTO_CIPHER_MODE_ECB) {
- const uint8_t *inptr = in;
- uint8_t *outptr = out;
- while (len) {
- if (len > AES_BLOCK_SIZE) {
- AES_encrypt(inptr, outptr, &ctxt->state.aes.encrypt_key);
- inptr += AES_BLOCK_SIZE;
- outptr += AES_BLOCK_SIZE;
- len -= AES_BLOCK_SIZE;
- } else {
- uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
- memcpy(tmp1, inptr, len);
- /* Fill with 0 to avoid valgrind uninitialized reads */
- memset(tmp1 + len, 0, sizeof(tmp1) - len);
- AES_encrypt(tmp1, tmp2, &ctxt->state.aes.encrypt_key);
- memcpy(outptr, tmp2, len);
- len = 0;
- }
- }
- } else {
+ switch (cipher->mode) {
+ case QCRYPTO_CIPHER_MODE_ECB:
+ qcrypto_cipher_aes_ecb_encrypt(&ctxt->state.aes.key.enc,
+ in, out, len);
+ break;
+ case QCRYPTO_CIPHER_MODE_CBC:
AES_cbc_encrypt(in, out, len,
- &ctxt->state.aes.encrypt_key,
+ &ctxt->state.aes.key.enc,
ctxt->state.aes.iv, 1);
+ break;
+ default:
+ g_assert_not_reached();
}
return 0;
@@ -112,29 +157,18 @@ static int qcrypto_cipher_decrypt_aes(QCryptoCipher
*cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
- if (cipher->mode == QCRYPTO_CIPHER_MODE_ECB) {
- const uint8_t *inptr = in;
- uint8_t *outptr = out;
- while (len) {
- if (len > AES_BLOCK_SIZE) {
- AES_decrypt(inptr, outptr, &ctxt->state.aes.decrypt_key);
- inptr += AES_BLOCK_SIZE;
- outptr += AES_BLOCK_SIZE;
- len -= AES_BLOCK_SIZE;
- } else {
- uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
- memcpy(tmp1, inptr, len);
- /* Fill with 0 to avoid valgrind uninitialized reads */
- memset(tmp1 + len, 0, sizeof(tmp1) - len);
- AES_decrypt(tmp1, tmp2, &ctxt->state.aes.decrypt_key);
- memcpy(outptr, tmp2, len);
- len = 0;
- }
- }
- } else {
+ switch (cipher->mode) {
+ case QCRYPTO_CIPHER_MODE_ECB:
+ qcrypto_cipher_aes_ecb_decrypt(&ctxt->state.aes.key.dec,
+ in, out, len);
+ break;
+ case QCRYPTO_CIPHER_MODE_CBC:
AES_cbc_encrypt(in, out, len,
- &ctxt->state.aes.decrypt_key,
+ &ctxt->state.aes.key.dec,
ctxt->state.aes.iv, 0);
+ break;
+ default:
+ g_assert_not_reached();
}
return 0;
@@ -173,12 +207,12 @@ static int qcrypto_cipher_init_aes(QCryptoCipher *cipher,
ctxt = g_new0(QCryptoCipherBuiltin, 1);
- if (AES_set_encrypt_key(key, nkey * 8, &ctxt->state.aes.encrypt_key) != 0)
{
+ if (AES_set_encrypt_key(key, nkey * 8, &ctxt->state.aes.key.enc) != 0) {
error_setg(errp, "Failed to set encryption key");
goto error;
}
- if (AES_set_decrypt_key(key, nkey * 8, &ctxt->state.aes.decrypt_key) != 0)
{
+ if (AES_set_decrypt_key(key, nkey * 8, &ctxt->state.aes.key.dec) != 0) {
error_setg(errp, "Failed to set decryption key");
goto error;
}
diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index 9b057fd..ed08782 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -42,16 +42,23 @@ static nettle_cipher_func aes_decrypt_wrapper;
static nettle_cipher_func des_encrypt_wrapper;
static nettle_cipher_func des_decrypt_wrapper;
+typedef struct QCryptoNettleAES {
+ struct aes_ctx enc;
+ struct aes_ctx dec;
+} QCryptoNettleAES;
+
static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
- aes_encrypt(ctx, length, dst, src);
+ const QCryptoNettleAES *aesctx = ctx;
+ aes_encrypt(&aesctx->enc, length, dst, src);
}
static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
uint8_t *dst, const uint8_t *src)
{
- aes_decrypt(ctx, length, dst, src);
+ const QCryptoNettleAES *aesctx = ctx;
+ aes_decrypt(&aesctx->dec, length, dst, src);
}
static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
@@ -104,8 +111,7 @@ static void twofish_decrypt_wrapper(cipher_ctx_t ctx,
cipher_length_t length,
typedef struct QCryptoCipherNettle QCryptoCipherNettle;
struct QCryptoCipherNettle {
- void *ctx_encrypt;
- void *ctx_decrypt;
+ void *ctx;
nettle_cipher_func *alg_encrypt;
nettle_cipher_func *alg_decrypt;
uint8_t *iv;
@@ -163,10 +169,9 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
switch (alg) {
case QCRYPTO_CIPHER_ALG_DES_RFB:
- ctx->ctx_encrypt = g_new0(struct des_ctx, 1);
- ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+ ctx->ctx = g_new0(struct des_ctx, 1);
rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
- des_set_key(ctx->ctx_encrypt, rfbkey);
+ des_set_key(ctx->ctx, rfbkey);
g_free(rfbkey);
ctx->alg_encrypt = des_encrypt_wrapper;
@@ -178,11 +183,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
case QCRYPTO_CIPHER_ALG_AES_128:
case QCRYPTO_CIPHER_ALG_AES_192:
case QCRYPTO_CIPHER_ALG_AES_256:
- ctx->ctx_encrypt = g_new0(struct aes_ctx, 1);
- ctx->ctx_decrypt = g_new0(struct aes_ctx, 1);
+ ctx->ctx = g_new0(QCryptoNettleAES, 1);
- aes_set_encrypt_key(ctx->ctx_encrypt, nkey, key);
- aes_set_decrypt_key(ctx->ctx_decrypt, nkey, key);
+ aes_set_encrypt_key(&((QCryptoNettleAES *)ctx->ctx)->enc, nkey, key);
+ aes_set_decrypt_key(&((QCryptoNettleAES *)ctx->ctx)->dec, nkey, key);
ctx->alg_encrypt = aes_encrypt_wrapper;
ctx->alg_decrypt = aes_decrypt_wrapper;
@@ -191,10 +195,9 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
break;
case QCRYPTO_CIPHER_ALG_CAST5_128:
- ctx->ctx_encrypt = g_new0(struct cast128_ctx, 1);
- ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+ ctx->ctx = g_new0(struct cast128_ctx, 1);
- cast5_set_key(ctx->ctx_encrypt, nkey, key);
+ cast5_set_key(ctx->ctx, nkey, key);
ctx->alg_encrypt = cast128_encrypt_wrapper;
ctx->alg_decrypt = cast128_decrypt_wrapper;
@@ -205,10 +208,9 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
case QCRYPTO_CIPHER_ALG_SERPENT_128:
case QCRYPTO_CIPHER_ALG_SERPENT_192:
case QCRYPTO_CIPHER_ALG_SERPENT_256:
- ctx->ctx_encrypt = g_new0(struct serpent_ctx, 1);
- ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+ ctx->ctx = g_new0(struct serpent_ctx, 1);
- serpent_set_key(ctx->ctx_encrypt, nkey, key);
+ serpent_set_key(ctx->ctx, nkey, key);
ctx->alg_encrypt = serpent_encrypt_wrapper;
ctx->alg_decrypt = serpent_decrypt_wrapper;
@@ -219,10 +221,9 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
case QCRYPTO_CIPHER_ALG_TWOFISH_128:
case QCRYPTO_CIPHER_ALG_TWOFISH_192:
case QCRYPTO_CIPHER_ALG_TWOFISH_256:
- ctx->ctx_encrypt = g_new0(struct twofish_ctx, 1);
- ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+ ctx->ctx = g_new0(struct twofish_ctx, 1);
- twofish_set_key(ctx->ctx_encrypt, nkey, key);
+ twofish_set_key(ctx->ctx, nkey, key);
ctx->alg_encrypt = twofish_encrypt_wrapper;
ctx->alg_decrypt = twofish_decrypt_wrapper;
@@ -257,8 +258,7 @@ void qcrypto_cipher_free(QCryptoCipher *cipher)
ctx = cipher->opaque;
g_free(ctx->iv);
- g_free(ctx->ctx_encrypt);
- g_free(ctx->ctx_decrypt);
+ g_free(ctx->ctx);
g_free(ctx);
g_free(cipher);
}
@@ -280,14 +280,15 @@ int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
switch (cipher->mode) {
case QCRYPTO_CIPHER_MODE_ECB:
- ctx->alg_encrypt(ctx->ctx_encrypt, len, out, in);
+ ctx->alg_encrypt(ctx->ctx, len, out, in);
break;
case QCRYPTO_CIPHER_MODE_CBC:
- cbc_encrypt(ctx->ctx_encrypt, ctx->alg_encrypt,
+ cbc_encrypt(ctx->ctx, ctx->alg_encrypt,
ctx->blocksize, ctx->iv,
len, out, in);
break;
+
default:
error_setg(errp, "Unsupported cipher algorithm %d",
cipher->alg);
@@ -313,15 +314,15 @@ int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
switch (cipher->mode) {
case QCRYPTO_CIPHER_MODE_ECB:
- ctx->alg_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt :
ctx->ctx_encrypt,
- len, out, in);
+ ctx->alg_decrypt(ctx->ctx, len, out, in);
break;
case QCRYPTO_CIPHER_MODE_CBC:
- cbc_decrypt(ctx->ctx_decrypt ? ctx->ctx_decrypt : ctx->ctx_encrypt,
- ctx->alg_decrypt, ctx->blocksize, ctx->iv,
+ cbc_decrypt(ctx->ctx, ctx->alg_decrypt,
+ ctx->blocksize, ctx->iv,
len, out, in);
break;
+
default:
error_setg(errp, "Unsupported cipher algorithm %d",
cipher->alg);
--
2.5.0
- [Qemu-devel] [PULL v2 00/13] Merge crypto code for LUKS encryption, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 01/13] crypto: add cryptographic random byte source, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 02/13] crypto: add support for PBKDF2 algorithm, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 07/13] crypto: add support for the serpent cipher algorithm, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 04/13] crypto: add support for anti-forensic split algorithm, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 08/13] crypto: add support for the twofish cipher algorithm, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 03/13] crypto: add support for generating initialization vectors, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 11/13] crypto: wire up XTS mode for cipher APIs, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 05/13] crypto: skip testing of unsupported cipher algorithms, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 06/13] crypto: add support for the cast5-128 cipher algorithm, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 10/13] crypto: refactor code for dealing with AES cipher,
Daniel P. Berrange <=
- [Qemu-devel] [PULL v2 09/13] crypto: import an implementation of the XTS cipher mode, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 13/13] crypto: implement the LUKS block encryption format, Daniel P. Berrange, 2016/03/17
- [Qemu-devel] [PULL v2 12/13] crypto: add block encryption framework, Daniel P. Berrange, 2016/03/17
- Re: [Qemu-devel] [PULL v2 00/13] Merge crypto code for LUKS encryption, Peter Maydell, 2016/03/17