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Fix increment of XSalsa20 192-bit nonce value.

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Handle nonce bytes in endian neutral way.
This commit is contained in:
Moinak Ghosh 2013-03-04 23:48:12 +05:30
parent dce424ec85
commit cf053c0257
3 changed files with 76 additions and 3 deletions
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9
crypto/aes/crypto_aes.c
View file

@ -137,7 +137,16 @@ aes_init(aes_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int pwd_len,
PKCS5_PBKDF2_HMAC((const char *)num, strlen((char *)num), salt,
saltlen, PBE_ROUNDS, EVP_sha256(), 32, IV);
ctx->nonce = lzma_crc64(IV, 32, 0);
} else {
tv = ntohll(ctx->nonce);
ctx->nonce = tv;
}
} else {
/*
* Random bytes are treated as being in big-endian format.
*/
tv = ntohll(ctx->nonce);
ctx->nonce = tv;
}
// Nullify stack components
memset(num, 0, 25);

65
crypto/xsalsa20/xsalsa20_xor.c
View file

@ -47,6 +47,10 @@ salsa20_init(salsa20_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int p
uint32_t r, p;
uint64_t N;
if (XSALSA20_CRYPTO_NONCEBYTES % 8) {
fprintf(stderr, "XSALSA20_CRYPTO_NONCEBYTES is not a multiple of 8!\n");
return (-1);
}
pickparams(&logN, &r, &p);
N = (uint64_t)(1) << logN;
if (crypto_scrypt(pwd, pwd_len, salt, saltlen, N, r, p, key, ctx->keylen)) {
@ -78,7 +82,10 @@ salsa20_init(salsa20_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int p
k = ctx->key + ctx->keylen;
memcpy(k, key, XSALSA20_CRYPTO_KEYBYTES - ctx->keylen);
}
if (enc) {
int i;
uint64_t *n, *n1;
// Derive 192-bit nonce
if (RAND_status() != 1 || RAND_bytes(IV, XSALSA20_CRYPTO_NONCEBYTES) != 1) {
@ -93,7 +100,13 @@ salsa20_init(salsa20_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int p
saltlen, PBE_ROUNDS, EVP_sha256(), 32, IV);
}
}
memcpy(ctx->nonce, IV, XSALSA20_CRYPTO_NONCEBYTES);
n = (uint64_t *)IV;
n1 = (uint64_t *)(ctx->nonce);
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES/8; i++) {
*n1 = ntohll(*n);
n++;
n1++;
}
// Nullify stack components
memset(num, 0, 25);
@ -110,13 +123,59 @@ salsa20_init(salsa20_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int p
int
salsa20_encrypt(salsa20_ctx_t *ctx, uchar_t *plaintext, uchar_t *ciphertext, uint64_t len, uint64_t id)
{
return (crypto_salsa20(ciphertext, plaintext, len, ctx->nonce + id, ctx->key, ctx->keylen));
uchar_t nonce[XSALSA20_CRYPTO_NONCEBYTES];
int i;
uint64_t *n, carry;
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES; i++) nonce[i] = ctx->nonce[i];
carry = id;
n = (uint64_t *)nonce;
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES/8; i++) {
if (UINT64_MAX - *n < carry) {
carry = carry - (UINT64_MAX - *n);
*n = 0;
} else {
*n += carry;
carry = 0;
break;
}
n++;
}
if (carry) {
n = (uint64_t *)nonce;
*n += carry;
}
return (crypto_salsa20(ciphertext, plaintext, len, nonce, ctx->key, ctx->keylen));
}
int
salsa20_decrypt(salsa20_ctx_t *ctx, uchar_t *ciphertext, uchar_t *plaintext, uint64_t len, uint64_t id)
{
return (crypto_salsa20(plaintext, ciphertext, len, ctx->nonce + id, ctx->key, ctx->keylen));
uchar_t nonce[XSALSA20_CRYPTO_NONCEBYTES];
int i;
uint64_t *n, carry;
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES; i++) nonce[i] = ctx->nonce[i];
carry = id;
n = (uint64_t *)nonce;
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES/8; i++) {
if (UINT64_MAX - *n < carry) {
carry = carry - (UINT64_MAX - *n);
*n = 0;
} else {
*n += carry;
carry = 0;
break;
}
n++;
}
if (carry) {
n = (uint64_t *)nonce;
*n += carry;
}
return (crypto_salsa20(plaintext, ciphertext, len, nonce, ctx->key, ctx->keylen));
}
uchar_t *

5
utils/utils.h
View file

@ -59,6 +59,11 @@ extern "C" {
# define UINT64_C(n) n ## UL
# endif
#endif
#ifndef UINT64_MAX
#define UINT64_MAX (18446744073709551615ULL)
#endif
typedef unsigned long uintptr_t;
typedef int32_t bsize_t;