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zerocopy crypto_secretbox_easy()

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This commit is contained in:
Frank Denis
2014-06-25 00:39:00 -07:00
parent f08666b0c6
commit 8e22264e85
1 changed files with 41 additions and 29 deletions
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src/libsodium/crypto_secretbox/crypto_secretbox_easy.c
+41 -29
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@@ -5,48 +5,60 @@
#include <stdlib.h>
#include <string.h>
#include "crypto_core_hsalsa20.h"
#include "crypto_onetimeauth_poly1305.h"
#include "crypto_secretbox.h"
#include "crypto_stream_salsa20.h"
#include "utils.h"
static const unsigned char sigma[16] = {
'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'
};
int
crypto_secretbox_easy(unsigned char *c, const unsigned char *m,
unsigned long long mlen, const unsigned char *n,
const unsigned char *k)
{
unsigned char *c_boxed;
unsigned char *m_boxed;
size_t c_boxed_len;
size_t m_boxed_len;
int rc;
crypto_onetimeauth_poly1305_state state;
unsigned char block0[64U];
unsigned char subkey[crypto_stream_salsa20_KEYBYTES];
unsigned long long i;
unsigned long long mlen0;
if (mlen > SIZE_MAX - crypto_secretbox_ZEROBYTES) {
if (mlen > SIZE_MAX - crypto_secretbox_MACBYTES) {
return -1;
}
(void) sizeof(char[crypto_secretbox_ZEROBYTES >=
crypto_secretbox_BOXZEROBYTES ? 1 : -1]);
m_boxed_len = (size_t) mlen + crypto_secretbox_ZEROBYTES;
if ((m_boxed = (unsigned char *) malloc((size_t) m_boxed_len)) == NULL) {
return -1;
crypto_core_hsalsa20(subkey, n, k, sigma);
memset(block0, 0U, crypto_secretbox_ZEROBYTES);
(void) sizeof(int[64U > crypto_secretbox_ZEROBYTES ? 1 : -1]);
mlen0 = mlen;
if (mlen0 > 64U - crypto_secretbox_ZEROBYTES) {
mlen0 = 64U - crypto_secretbox_ZEROBYTES;
}
c_boxed_len = (size_t) mlen + crypto_secretbox_ZEROBYTES;
if ((c_boxed = (unsigned char *) malloc(c_boxed_len)) == NULL) {
free(m_boxed);
return -1;
for (i = 0U; i < mlen0; i++) {
block0[i + crypto_secretbox_ZEROBYTES] = m[i];
}
memset(m_boxed, 0, crypto_secretbox_ZEROBYTES);
memcpy(m_boxed + crypto_secretbox_ZEROBYTES, m, mlen);
rc = crypto_secretbox(c_boxed, m_boxed, m_boxed_len, n, k);
sodium_memzero(m_boxed, m_boxed_len);
free(m_boxed);
if (rc != 0) {
free(c_boxed);
return -1;
crypto_stream_salsa20_xor(block0, block0,
mlen0 + crypto_secretbox_ZEROBYTES,
n + 16, subkey);
crypto_onetimeauth_poly1305_init(&state, block0);
memcpy(c + crypto_secretbox_MACBYTES,
block0 + crypto_secretbox_ZEROBYTES, mlen0);
sodium_memzero(block0, sizeof block0);
if (mlen > mlen0) {
crypto_stream_salsa20_xor_ic(c + crypto_secretbox_MACBYTES + mlen0,
m + mlen0, mlen - mlen0,
n + 16, 1U, subkey);
}
assert(m_boxed_len - crypto_secretbox_BOXZEROBYTES ==
mlen + crypto_secretbox_MACBYTES);
memcpy(c, c_boxed + crypto_secretbox_BOXZEROBYTES,
mlen + crypto_secretbox_MACBYTES);
free(c_boxed);
sodium_memzero(subkey, sizeof subkey);
crypto_onetimeauth_poly1305_update
(&state, c + crypto_secretbox_MACBYTES, mlen);
crypto_onetimeauth_poly1305_final(&state, c);
sodium_memzero(&state, sizeof state);
return 0;
}
@@ -63,7 +75,7 @@ crypto_secretbox_open_easy(unsigned char *m, const unsigned char *c,
int rc;
(void) sizeof(int[crypto_secretbox_BOXZEROBYTES + crypto_secretbox_MACBYTES
== crypto_secretbox_ZEROBYTES]);
== crypto_secretbox_ZEROBYTES ? 1 : -1]);
if (clen < crypto_secretbox_MACBYTES ||
clen > SIZE_MAX - crypto_secretbox_BOXZEROBYTES) {
return -1;