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openssl/crypto/aes/aes_ige.c
Rich Salz b1498c98f3 Don't call memcpy if len is zero. 
Prevent undefined behavior in CRYPTO_cbc128_encrypt: calling this function
with the 'len' parameter being 0 would result in a memcpy where the source
and destination parameters are the same, which is undefined behavior.
Do same for AES_ige_encrypt.

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2671)
2017-02-20 19:17:53 -05:00

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/*
* Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/cryptlib.h"
#include <openssl/aes.h>
#include "aes_locl.h"
#define N_WORDS (AES_BLOCK_SIZE / sizeof(unsigned long))
typedef struct {
unsigned long data[N_WORDS];
} aes_block_t;
/* XXX: probably some better way to do this */
#if defined(__i386__) || defined(__x86_64__)
# define UNALIGNED_MEMOPS_ARE_FAST 1
#else
# define UNALIGNED_MEMOPS_ARE_FAST 0
#endif
#if UNALIGNED_MEMOPS_ARE_FAST
# define load_block(d, s) (d) = *(const aes_block_t *)(s)
# define store_block(d, s) *(aes_block_t *)(d) = (s)
#else
# define load_block(d, s) memcpy((d).data, (s), AES_BLOCK_SIZE)
# define store_block(d, s) memcpy((d), (s).data, AES_BLOCK_SIZE)
#endif
/* N.B. The IV for this mode is _twice_ the block size */
void AES_ige_encrypt(const unsigned char *in, unsigned char *out,
size_t length, const AES_KEY *key,
unsigned char *ivec, const int enc)
{
size_t n;
size_t len = length;
if (length == 0)
return;
OPENSSL_assert(in && out && key && ivec);
OPENSSL_assert((AES_ENCRYPT == enc) || (AES_DECRYPT == enc));
OPENSSL_assert((length % AES_BLOCK_SIZE) == 0);
len = length / AES_BLOCK_SIZE;
if (AES_ENCRYPT == enc) {
if (in != out &&
(UNALIGNED_MEMOPS_ARE_FAST
|| ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(long) ==
0)) {
aes_block_t *ivp = (aes_block_t *) ivec;
aes_block_t *iv2p = (aes_block_t *) (ivec + AES_BLOCK_SIZE);
while (len) {
aes_block_t *inp = (aes_block_t *) in;
aes_block_t *outp = (aes_block_t *) out;
for (n = 0; n < N_WORDS; ++n)
outp->data[n] = inp->data[n] ^ ivp->data[n];
AES_encrypt((unsigned char *)outp->data,
(unsigned char *)outp->data, key);
for (n = 0; n < N_WORDS; ++n)
outp->data[n] ^= iv2p->data[n];
ivp = outp;
iv2p = inp;
--len;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
memcpy(ivec, ivp->data, AES_BLOCK_SIZE);
memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);
} else {
aes_block_t tmp, tmp2;
aes_block_t iv;
aes_block_t iv2;
load_block(iv, ivec);
load_block(iv2, ivec + AES_BLOCK_SIZE);
while (len) {
load_block(tmp, in);
for (n = 0; n < N_WORDS; ++n)
tmp2.data[n] = tmp.data[n] ^ iv.data[n];
AES_encrypt((unsigned char *)tmp2.data,
(unsigned char *)tmp2.data, key);
for (n = 0; n < N_WORDS; ++n)
tmp2.data[n] ^= iv2.data[n];
store_block(out, tmp2);
iv = tmp2;
iv2 = tmp;
--len;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
memcpy(ivec, iv.data, AES_BLOCK_SIZE);
memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);
}
} else {
if (in != out &&
(UNALIGNED_MEMOPS_ARE_FAST
|| ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(long) ==
0)) {
aes_block_t *ivp = (aes_block_t *) ivec;
aes_block_t *iv2p = (aes_block_t *) (ivec + AES_BLOCK_SIZE);
while (len) {
aes_block_t tmp;
aes_block_t *inp = (aes_block_t *) in;
aes_block_t *outp = (aes_block_t *) out;
for (n = 0; n < N_WORDS; ++n)
tmp.data[n] = inp->data[n] ^ iv2p->data[n];
AES_decrypt((unsigned char *)tmp.data,
(unsigned char *)outp->data, key);
for (n = 0; n < N_WORDS; ++n)
outp->data[n] ^= ivp->data[n];
ivp = inp;
iv2p = outp;
--len;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
memcpy(ivec, ivp->data, AES_BLOCK_SIZE);
memcpy(ivec + AES_BLOCK_SIZE, iv2p->data, AES_BLOCK_SIZE);
} else {
aes_block_t tmp, tmp2;
aes_block_t iv;
aes_block_t iv2;
load_block(iv, ivec);
load_block(iv2, ivec + AES_BLOCK_SIZE);
while (len) {
load_block(tmp, in);
tmp2 = tmp;
for (n = 0; n < N_WORDS; ++n)
tmp.data[n] ^= iv2.data[n];
AES_decrypt((unsigned char *)tmp.data,
(unsigned char *)tmp.data, key);
for (n = 0; n < N_WORDS; ++n)
tmp.data[n] ^= iv.data[n];
store_block(out, tmp);
iv = tmp2;
iv2 = tmp;
--len;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
memcpy(ivec, iv.data, AES_BLOCK_SIZE);
memcpy(ivec + AES_BLOCK_SIZE, iv2.data, AES_BLOCK_SIZE);
}
}
}
/*
* Note that its effectively impossible to do biIGE in anything other
* than a single pass, so no provision is made for chaining.
*/
/* N.B. The IV for this mode is _four times_ the block size */
void AES_bi_ige_encrypt(const unsigned char *in, unsigned char *out,
size_t length, const AES_KEY *key,
const AES_KEY *key2, const unsigned char *ivec,
const int enc)
{
size_t n;
size_t len = length;
unsigned char tmp[AES_BLOCK_SIZE];
unsigned char tmp2[AES_BLOCK_SIZE];
unsigned char tmp3[AES_BLOCK_SIZE];
unsigned char prev[AES_BLOCK_SIZE];
const unsigned char *iv;
const unsigned char *iv2;
OPENSSL_assert(in && out && key && ivec);
OPENSSL_assert((AES_ENCRYPT == enc) || (AES_DECRYPT == enc));
OPENSSL_assert((length % AES_BLOCK_SIZE) == 0);
if (AES_ENCRYPT == enc) {
/*
* XXX: Do a separate case for when in != out (strictly should check
* for overlap, too)
*/
/* First the forward pass */
iv = ivec;
iv2 = ivec + AES_BLOCK_SIZE;
while (len >= AES_BLOCK_SIZE) {
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] = in[n] ^ iv[n];
AES_encrypt(out, out, key);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] ^= iv2[n];
iv = out;
memcpy(prev, in, AES_BLOCK_SIZE);
iv2 = prev;
len -= AES_BLOCK_SIZE;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
/* And now backwards */
iv = ivec + AES_BLOCK_SIZE * 2;
iv2 = ivec + AES_BLOCK_SIZE * 3;
len = length;
while (len >= AES_BLOCK_SIZE) {
out -= AES_BLOCK_SIZE;
/*
* XXX: reduce copies by alternating between buffers
*/
memcpy(tmp, out, AES_BLOCK_SIZE);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] ^= iv[n];
/*
* hexdump(stdout, "out ^ iv", out, AES_BLOCK_SIZE);
*/
AES_encrypt(out, out, key);
/*
* hexdump(stdout,"enc", out, AES_BLOCK_SIZE);
*/
/*
* hexdump(stdout,"iv2", iv2, AES_BLOCK_SIZE);
*/
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] ^= iv2[n];
/*
* hexdump(stdout,"out", out, AES_BLOCK_SIZE);
*/
iv = out;
memcpy(prev, tmp, AES_BLOCK_SIZE);
iv2 = prev;
len -= AES_BLOCK_SIZE;
}
} else {
/* First backwards */
iv = ivec + AES_BLOCK_SIZE * 2;
iv2 = ivec + AES_BLOCK_SIZE * 3;
in += length;
out += length;
while (len >= AES_BLOCK_SIZE) {
in -= AES_BLOCK_SIZE;
out -= AES_BLOCK_SIZE;
memcpy(tmp, in, AES_BLOCK_SIZE);
memcpy(tmp2, in, AES_BLOCK_SIZE);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
tmp[n] ^= iv2[n];
AES_decrypt(tmp, out, key);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] ^= iv[n];
memcpy(tmp3, tmp2, AES_BLOCK_SIZE);
iv = tmp3;
iv2 = out;
len -= AES_BLOCK_SIZE;
}
/* And now forwards */
iv = ivec;
iv2 = ivec + AES_BLOCK_SIZE;
len = length;
while (len >= AES_BLOCK_SIZE) {
memcpy(tmp, out, AES_BLOCK_SIZE);
memcpy(tmp2, out, AES_BLOCK_SIZE);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
tmp[n] ^= iv2[n];
AES_decrypt(tmp, out, key);
for (n = 0; n < AES_BLOCK_SIZE; ++n)
out[n] ^= iv[n];
memcpy(tmp3, tmp2, AES_BLOCK_SIZE);
iv = tmp3;
iv2 = out;
len -= AES_BLOCK_SIZE;
in += AES_BLOCK_SIZE;
out += AES_BLOCK_SIZE;
}
}
}
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