/*
* Copyright (c) 2018-2019 iXsystems Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/param.h>
#include <sys/endian.h>
#include <opencrypto/cbc_mac.h>
#include <opencrypto/xform_auth.h>
/*
* Given two CCM_CBC_BLOCK_LEN blocks, xor
* them into dst, and then encrypt dst.
*/
static void
xor_and_encrypt(struct aes_cbc_mac_ctx *ctx,
const uint8_t *src, uint8_t *dst)
{
const uint64_t *b1;
uint64_t *b2;
uint64_t temp_block[CCM_CBC_BLOCK_LEN/sizeof(uint64_t)];
b1 = (const uint64_t*)src;
b2 = (uint64_t*)dst;
for (size_t count = 0;
count < CCM_CBC_BLOCK_LEN/sizeof(uint64_t);
count++) {
temp_block[count] = b1[count] ^ b2[count];
}
rijndaelEncrypt(ctx->keysched, ctx->rounds, (void*)temp_block, dst);
}
void
AES_CBC_MAC_Init(struct aes_cbc_mac_ctx *ctx)
{
bzero(ctx, sizeof(*ctx));
}
void
AES_CBC_MAC_Setkey(struct aes_cbc_mac_ctx *ctx, const uint8_t *key, uint16_t klen)
{
ctx->rounds = rijndaelKeySetupEnc(ctx->keysched, key, klen * 8);
}
/*
* This is called to set the nonce, aka IV.
* Before this call, the authDataLength and cryptDataLength fields
* MUST have been set. Sadly, there's no way to return an error.
*
* The CBC-MAC algorithm requires that the first block contain the
* nonce, as well as information about the sizes and lengths involved.
*/
void
AES_CBC_MAC_Reinit(struct aes_cbc_mac_ctx *ctx, const uint8_t *nonce, uint16_t nonceLen)
{
uint8_t b0[CCM_CBC_BLOCK_LEN];
uint8_t *bp = b0, flags = 0;
uint8_t L = 0;
uint64_t dataLength = ctx->cryptDataLength;
KASSERT(nonceLen >= 7 && nonceLen <= 13,
("nonceLen must be between 7 and 13 bytes"));
ctx->nonce = nonce;
ctx->nonceLength = nonceLen;
ctx->authDataCount = 0;
ctx->blockIndex = 0;
explicit_bzero(ctx->staging_block, sizeof(ctx->staging_block));
/*
* Need to determine the L field value. This is the number of
* bytes needed to specify the length of the message; the length
* is whatever is left in the 16 bytes after specifying flags and
* the nonce.
*/
L = 15 - nonceLen;
flags = ((ctx->authDataLength > 0) << 6) +
(((AES_CBC_MAC_HASH_LEN - 2) / 2) << 3) +
L - 1;
/*
* Now we need to set up the first block, which has flags, nonce,
* and the message length.
*/
b0[0] = flags;
bcopy(nonce, b0 + 1, nonceLen);
bp = b0 + 1 + nonceLen;
/* Need to copy L' [aka L-1] bytes of cryptDataLength */
for (uint8_t *dst = b0 + sizeof(b0) - 1; dst >= bp; dst--) {
*dst = dataLength;
dataLength >>= 8;
}
/* Now need to encrypt b0 */
rijndaelEncrypt(ctx->keysched, ctx->rounds, b0, ctx->block);
/* If there is auth data, we need to set up the staging block */
if (ctx->authDataLength) {
size_t addLength;
if (ctx->authDataLength < ((1<<16) - (1<<8))) {
uint16_t sizeVal = htobe16(ctx->authDataLength);
bcopy(&sizeVal, ctx->staging_block, sizeof(sizeVal));
addLength = sizeof(sizeVal);
} else if (ctx->authDataLength < (1ULL<<32)) {
uint32_t sizeVal = htobe32(ctx->authDataLength);
ctx->staging_block[0] = 0xff;
ctx->staging_block[1] = 0xfe;
bcopy(&sizeVal, ctx->staging_block+2, sizeof(sizeVal));
addLength = 2 + sizeof(sizeVal);
} else {
uint64_t sizeVal = htobe64(ctx->authDataLength);
ctx->staging_block[0] = 0xff;
ctx->staging_block[1] = 0xff;
bcopy(&sizeVal, ctx->staging_block+2, sizeof(sizeVal));
addLength = 2 + sizeof(sizeVal);
}
ctx->blockIndex = addLength;
/*
* The length descriptor goes into the AAD buffer, so we
* need to account for it.
*/
ctx->authDataLength += addLength;
ctx->authDataCount = addLength;
}
}
int
AES_CBC_MAC_Update(struct aes_cbc_mac_ctx *ctx, const uint8_t *data,
uint16_t length)
{
size_t copy_amt;
/*
* This will be called in one of two phases:
* (1) Applying authentication data, or
* (2) Applying the payload data.
*
* Because CBC-MAC puts the authentication data size before the
* data, subsequent calls won't be block-size-aligned. Which
* complicates things a fair bit.
*
* The payload data doesn't have that problem.
*/
if (ctx->authDataCount < ctx->authDataLength) {
/*
* We need to process data as authentication data.
* Since we may be out of sync, we may also need
* to pad out the staging block.
*/
const uint8_t *ptr = data;
while (length > 0) {
copy_amt = MIN(length,
sizeof(ctx->staging_block) - ctx->blockIndex);
bcopy(ptr, ctx->staging_block + ctx->blockIndex,
copy_amt);
ptr += copy_amt;
length -= copy_amt;
ctx->authDataCount += copy_amt;
ctx->blockIndex += copy_amt;
ctx->blockIndex %= sizeof(ctx->staging_block);
if (ctx->blockIndex == 0 ||
ctx->authDataCount == ctx->authDataLength) {
/*
* We're done with this block, so we
* xor staging_block with block, and then
* encrypt it.
*/
xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
bzero(ctx->staging_block, sizeof(ctx->staging_block));
ctx->blockIndex = 0;
if (ctx->authDataCount >= ctx->authDataLength)
break;
}
}
/*
* We'd like to be able to check length == 0 and return
* here, but the way OCF calls us, length is always
* blksize (16, in this case). So we have to count on
* the fact that OCF calls us separately for the AAD and
* for the real data.
*/
return (0);
}
/*
* If we're here, then we're encoding payload data.
* This is marginally easier, except that _Update can
* be called with non-aligned update lengths. As a result,
* we still need to use the staging block.
*/
KASSERT((length + ctx->cryptDataCount) <= ctx->cryptDataLength,
("More encryption data than allowed"));
while (length) {
uint8_t *ptr;
copy_amt = MIN(sizeof(ctx->staging_block) - ctx->blockIndex,
length);
ptr = ctx->staging_block + ctx->blockIndex;
bcopy(data, ptr, copy_amt);
data += copy_amt;
ctx->blockIndex += copy_amt;
ctx->cryptDataCount += copy_amt;
length -= copy_amt;
if (ctx->blockIndex == sizeof(ctx->staging_block)) {
/* We've got a full block */
xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
ctx->blockIndex = 0;
bzero(ctx->staging_block, sizeof(ctx->staging_block));
}
}
return (0);
}
void
AES_CBC_MAC_Final(uint8_t *buf, struct aes_cbc_mac_ctx *ctx)
{
uint8_t s0[CCM_CBC_BLOCK_LEN];
/*
* We first need to check to see if we've got any data
* left over to encrypt.
*/
if (ctx->blockIndex != 0) {
xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
ctx->cryptDataCount += ctx->blockIndex;
ctx->blockIndex = 0;
explicit_bzero(ctx->staging_block, sizeof(ctx->staging_block));
}
bzero(s0, sizeof(s0));
s0[0] = (15 - ctx->nonceLength) - 1;
bcopy(ctx->nonce, s0 + 1, ctx->nonceLength);
rijndaelEncrypt(ctx->keysched, ctx->rounds, s0, s0);
for (size_t indx = 0; indx < AES_CBC_MAC_HASH_LEN; indx++)
buf[indx] = ctx->block[indx] ^ s0[indx];
explicit_bzero(s0, sizeof(s0));
}