559 lines
16 KiB
C
559 lines
16 KiB
C
/*
|
|
* Copyright 2014-2020 The OpenSSL Project Authors. All Rights Reserved.
|
|
*
|
|
* Licensed under the Apache License 2.0 (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 <string.h>
|
|
#include <openssl/crypto.h>
|
|
#include <openssl/err.h>
|
|
#include "crypto/modes.h"
|
|
|
|
#ifndef OPENSSL_NO_OCB
|
|
|
|
/*
|
|
* Calculate the number of binary trailing zero's in any given number
|
|
*/
|
|
static u32 ocb_ntz(u64 n)
|
|
{
|
|
u32 cnt = 0;
|
|
|
|
/*
|
|
* We do a right-to-left simple sequential search. This is surprisingly
|
|
* efficient as the distribution of trailing zeros is not uniform,
|
|
* e.g. the number of possible inputs with no trailing zeros is equal to
|
|
* the number with 1 or more; the number with exactly 1 is equal to the
|
|
* number with 2 or more, etc. Checking the last two bits covers 75% of
|
|
* all numbers. Checking the last three covers 87.5%
|
|
*/
|
|
while (!(n & 1)) {
|
|
n >>= 1;
|
|
cnt++;
|
|
}
|
|
return cnt;
|
|
}
|
|
|
|
/*
|
|
* Shift a block of 16 bytes left by shift bits
|
|
*/
|
|
static void ocb_block_lshift(const unsigned char *in, size_t shift,
|
|
unsigned char *out)
|
|
{
|
|
int i;
|
|
unsigned char carry = 0, carry_next;
|
|
|
|
for (i = 15; i >= 0; i--) {
|
|
carry_next = in[i] >> (8 - shift);
|
|
out[i] = (in[i] << shift) | carry;
|
|
carry = carry_next;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Perform a "double" operation as per OCB spec
|
|
*/
|
|
static void ocb_double(OCB_BLOCK *in, OCB_BLOCK *out)
|
|
{
|
|
unsigned char mask;
|
|
|
|
/*
|
|
* Calculate the mask based on the most significant bit. There are more
|
|
* efficient ways to do this - but this way is constant time
|
|
*/
|
|
mask = in->c[0] & 0x80;
|
|
mask >>= 7;
|
|
mask = (0 - mask) & 0x87;
|
|
|
|
ocb_block_lshift(in->c, 1, out->c);
|
|
|
|
out->c[15] ^= mask;
|
|
}
|
|
|
|
/*
|
|
* Perform an xor on in1 and in2 - each of len bytes. Store result in out
|
|
*/
|
|
static void ocb_block_xor(const unsigned char *in1,
|
|
const unsigned char *in2, size_t len,
|
|
unsigned char *out)
|
|
{
|
|
size_t i;
|
|
for (i = 0; i < len; i++) {
|
|
out[i] = in1[i] ^ in2[i];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Lookup L_index in our lookup table. If we haven't already got it we need to
|
|
* calculate it
|
|
*/
|
|
static OCB_BLOCK *ocb_lookup_l(OCB128_CONTEXT *ctx, size_t idx)
|
|
{
|
|
size_t l_index = ctx->l_index;
|
|
|
|
if (idx <= l_index) {
|
|
return ctx->l + idx;
|
|
}
|
|
|
|
/* We don't have it - so calculate it */
|
|
if (idx >= ctx->max_l_index) {
|
|
void *tmp_ptr;
|
|
/*
|
|
* Each additional entry allows to process almost double as
|
|
* much data, so that in linear world the table will need to
|
|
* be expanded with smaller and smaller increments. Originally
|
|
* it was doubling in size, which was a waste. Growing it
|
|
* linearly is not formally optimal, but is simpler to implement.
|
|
* We grow table by minimally required 4*n that would accommodate
|
|
* the index.
|
|
*/
|
|
ctx->max_l_index += (idx - ctx->max_l_index + 4) & ~3;
|
|
tmp_ptr = OPENSSL_realloc(ctx->l, ctx->max_l_index * sizeof(OCB_BLOCK));
|
|
if (tmp_ptr == NULL) /* prevent ctx->l from being clobbered */
|
|
return NULL;
|
|
ctx->l = tmp_ptr;
|
|
}
|
|
while (l_index < idx) {
|
|
ocb_double(ctx->l + l_index, ctx->l + l_index + 1);
|
|
l_index++;
|
|
}
|
|
ctx->l_index = l_index;
|
|
|
|
return ctx->l + idx;
|
|
}
|
|
|
|
/*
|
|
* Create a new OCB128_CONTEXT
|
|
*/
|
|
OCB128_CONTEXT *CRYPTO_ocb128_new(void *keyenc, void *keydec,
|
|
block128_f encrypt, block128_f decrypt,
|
|
ocb128_f stream)
|
|
{
|
|
OCB128_CONTEXT *octx;
|
|
int ret;
|
|
|
|
if ((octx = OPENSSL_malloc(sizeof(*octx))) != NULL) {
|
|
ret = CRYPTO_ocb128_init(octx, keyenc, keydec, encrypt, decrypt,
|
|
stream);
|
|
if (ret)
|
|
return octx;
|
|
OPENSSL_free(octx);
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Initialise an existing OCB128_CONTEXT
|
|
*/
|
|
int CRYPTO_ocb128_init(OCB128_CONTEXT *ctx, void *keyenc, void *keydec,
|
|
block128_f encrypt, block128_f decrypt,
|
|
ocb128_f stream)
|
|
{
|
|
memset(ctx, 0, sizeof(*ctx));
|
|
ctx->l_index = 0;
|
|
ctx->max_l_index = 5;
|
|
if ((ctx->l = OPENSSL_malloc(ctx->max_l_index * 16)) == NULL)
|
|
return 0;
|
|
|
|
/*
|
|
* We set both the encryption and decryption key schedules - decryption
|
|
* needs both. Don't really need decryption schedule if only doing
|
|
* encryption - but it simplifies things to take it anyway
|
|
*/
|
|
ctx->encrypt = encrypt;
|
|
ctx->decrypt = decrypt;
|
|
ctx->stream = stream;
|
|
ctx->keyenc = keyenc;
|
|
ctx->keydec = keydec;
|
|
|
|
/* L_* = ENCIPHER(K, zeros(128)) */
|
|
ctx->encrypt(ctx->l_star.c, ctx->l_star.c, ctx->keyenc);
|
|
|
|
/* L_$ = double(L_*) */
|
|
ocb_double(&ctx->l_star, &ctx->l_dollar);
|
|
|
|
/* L_0 = double(L_$) */
|
|
ocb_double(&ctx->l_dollar, ctx->l);
|
|
|
|
/* L_{i} = double(L_{i-1}) */
|
|
ocb_double(ctx->l, ctx->l+1);
|
|
ocb_double(ctx->l+1, ctx->l+2);
|
|
ocb_double(ctx->l+2, ctx->l+3);
|
|
ocb_double(ctx->l+3, ctx->l+4);
|
|
ctx->l_index = 4; /* enough to process up to 496 bytes */
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Copy an OCB128_CONTEXT object
|
|
*/
|
|
int CRYPTO_ocb128_copy_ctx(OCB128_CONTEXT *dest, OCB128_CONTEXT *src,
|
|
void *keyenc, void *keydec)
|
|
{
|
|
memcpy(dest, src, sizeof(OCB128_CONTEXT));
|
|
if (keyenc)
|
|
dest->keyenc = keyenc;
|
|
if (keydec)
|
|
dest->keydec = keydec;
|
|
if (src->l) {
|
|
if ((dest->l = OPENSSL_malloc(src->max_l_index * 16)) == NULL)
|
|
return 0;
|
|
memcpy(dest->l, src->l, (src->l_index + 1) * 16);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Set the IV to be used for this operation. Must be 1 - 15 bytes.
|
|
*/
|
|
int CRYPTO_ocb128_setiv(OCB128_CONTEXT *ctx, const unsigned char *iv,
|
|
size_t len, size_t taglen)
|
|
{
|
|
unsigned char ktop[16], tmp[16], mask;
|
|
unsigned char stretch[24], nonce[16];
|
|
size_t bottom, shift;
|
|
|
|
/*
|
|
* Spec says IV is 120 bits or fewer - it allows non byte aligned lengths.
|
|
* We don't support this at this stage
|
|
*/
|
|
if ((len > 15) || (len < 1) || (taglen > 16) || (taglen < 1)) {
|
|
return -1;
|
|
}
|
|
|
|
/* Reset nonce-dependent variables */
|
|
memset(&ctx->sess, 0, sizeof(ctx->sess));
|
|
|
|
/* Nonce = num2str(TAGLEN mod 128,7) || zeros(120-bitlen(N)) || 1 || N */
|
|
nonce[0] = ((taglen * 8) % 128) << 1;
|
|
memset(nonce + 1, 0, 15);
|
|
memcpy(nonce + 16 - len, iv, len);
|
|
nonce[15 - len] |= 1;
|
|
|
|
/* Ktop = ENCIPHER(K, Nonce[1..122] || zeros(6)) */
|
|
memcpy(tmp, nonce, 16);
|
|
tmp[15] &= 0xc0;
|
|
ctx->encrypt(tmp, ktop, ctx->keyenc);
|
|
|
|
/* Stretch = Ktop || (Ktop[1..64] xor Ktop[9..72]) */
|
|
memcpy(stretch, ktop, 16);
|
|
ocb_block_xor(ktop, ktop + 1, 8, stretch + 16);
|
|
|
|
/* bottom = str2num(Nonce[123..128]) */
|
|
bottom = nonce[15] & 0x3f;
|
|
|
|
/* Offset_0 = Stretch[1+bottom..128+bottom] */
|
|
shift = bottom % 8;
|
|
ocb_block_lshift(stretch + (bottom / 8), shift, ctx->sess.offset.c);
|
|
mask = 0xff;
|
|
mask <<= 8 - shift;
|
|
ctx->sess.offset.c[15] |=
|
|
(*(stretch + (bottom / 8) + 16) & mask) >> (8 - shift);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Provide any AAD. This can be called multiple times. Only the final time can
|
|
* have a partial block
|
|
*/
|
|
int CRYPTO_ocb128_aad(OCB128_CONTEXT *ctx, const unsigned char *aad,
|
|
size_t len)
|
|
{
|
|
u64 i, all_num_blocks;
|
|
size_t num_blocks, last_len;
|
|
OCB_BLOCK tmp;
|
|
|
|
/* Calculate the number of blocks of AAD provided now, and so far */
|
|
num_blocks = len / 16;
|
|
all_num_blocks = num_blocks + ctx->sess.blocks_hashed;
|
|
|
|
/* Loop through all full blocks of AAD */
|
|
for (i = ctx->sess.blocks_hashed + 1; i <= all_num_blocks; i++) {
|
|
OCB_BLOCK *lookup;
|
|
|
|
/* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
|
|
lookup = ocb_lookup_l(ctx, ocb_ntz(i));
|
|
if (lookup == NULL)
|
|
return 0;
|
|
ocb_block16_xor(&ctx->sess.offset_aad, lookup, &ctx->sess.offset_aad);
|
|
|
|
memcpy(tmp.c, aad, 16);
|
|
aad += 16;
|
|
|
|
/* Sum_i = Sum_{i-1} xor ENCIPHER(K, A_i xor Offset_i) */
|
|
ocb_block16_xor(&ctx->sess.offset_aad, &tmp, &tmp);
|
|
ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);
|
|
ocb_block16_xor(&tmp, &ctx->sess.sum, &ctx->sess.sum);
|
|
}
|
|
|
|
/*
|
|
* Check if we have any partial blocks left over. This is only valid in the
|
|
* last call to this function
|
|
*/
|
|
last_len = len % 16;
|
|
|
|
if (last_len > 0) {
|
|
/* Offset_* = Offset_m xor L_* */
|
|
ocb_block16_xor(&ctx->sess.offset_aad, &ctx->l_star,
|
|
&ctx->sess.offset_aad);
|
|
|
|
/* CipherInput = (A_* || 1 || zeros(127-bitlen(A_*))) xor Offset_* */
|
|
memset(tmp.c, 0, 16);
|
|
memcpy(tmp.c, aad, last_len);
|
|
tmp.c[last_len] = 0x80;
|
|
ocb_block16_xor(&ctx->sess.offset_aad, &tmp, &tmp);
|
|
|
|
/* Sum = Sum_m xor ENCIPHER(K, CipherInput) */
|
|
ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);
|
|
ocb_block16_xor(&tmp, &ctx->sess.sum, &ctx->sess.sum);
|
|
}
|
|
|
|
ctx->sess.blocks_hashed = all_num_blocks;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Provide any data to be encrypted. This can be called multiple times. Only
|
|
* the final time can have a partial block
|
|
*/
|
|
int CRYPTO_ocb128_encrypt(OCB128_CONTEXT *ctx,
|
|
const unsigned char *in, unsigned char *out,
|
|
size_t len)
|
|
{
|
|
u64 i, all_num_blocks;
|
|
size_t num_blocks, last_len;
|
|
|
|
/*
|
|
* Calculate the number of blocks of data to be encrypted provided now, and
|
|
* so far
|
|
*/
|
|
num_blocks = len / 16;
|
|
all_num_blocks = num_blocks + ctx->sess.blocks_processed;
|
|
|
|
if (num_blocks && all_num_blocks == (size_t)all_num_blocks
|
|
&& ctx->stream != NULL) {
|
|
size_t max_idx = 0, top = (size_t)all_num_blocks;
|
|
|
|
/*
|
|
* See how many L_{i} entries we need to process data at hand
|
|
* and pre-compute missing entries in the table [if any]...
|
|
*/
|
|
while (top >>= 1)
|
|
max_idx++;
|
|
if (ocb_lookup_l(ctx, max_idx) == NULL)
|
|
return 0;
|
|
|
|
ctx->stream(in, out, num_blocks, ctx->keyenc,
|
|
(size_t)ctx->sess.blocks_processed + 1, ctx->sess.offset.c,
|
|
(const unsigned char (*)[16])ctx->l, ctx->sess.checksum.c);
|
|
} else {
|
|
/* Loop through all full blocks to be encrypted */
|
|
for (i = ctx->sess.blocks_processed + 1; i <= all_num_blocks; i++) {
|
|
OCB_BLOCK *lookup;
|
|
OCB_BLOCK tmp;
|
|
|
|
/* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
|
|
lookup = ocb_lookup_l(ctx, ocb_ntz(i));
|
|
if (lookup == NULL)
|
|
return 0;
|
|
ocb_block16_xor(&ctx->sess.offset, lookup, &ctx->sess.offset);
|
|
|
|
memcpy(tmp.c, in, 16);
|
|
in += 16;
|
|
|
|
/* Checksum_i = Checksum_{i-1} xor P_i */
|
|
ocb_block16_xor(&tmp, &ctx->sess.checksum, &ctx->sess.checksum);
|
|
|
|
/* C_i = Offset_i xor ENCIPHER(K, P_i xor Offset_i) */
|
|
ocb_block16_xor(&ctx->sess.offset, &tmp, &tmp);
|
|
ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);
|
|
ocb_block16_xor(&ctx->sess.offset, &tmp, &tmp);
|
|
|
|
memcpy(out, tmp.c, 16);
|
|
out += 16;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if we have any partial blocks left over. This is only valid in the
|
|
* last call to this function
|
|
*/
|
|
last_len = len % 16;
|
|
|
|
if (last_len > 0) {
|
|
OCB_BLOCK pad;
|
|
|
|
/* Offset_* = Offset_m xor L_* */
|
|
ocb_block16_xor(&ctx->sess.offset, &ctx->l_star, &ctx->sess.offset);
|
|
|
|
/* Pad = ENCIPHER(K, Offset_*) */
|
|
ctx->encrypt(ctx->sess.offset.c, pad.c, ctx->keyenc);
|
|
|
|
/* C_* = P_* xor Pad[1..bitlen(P_*)] */
|
|
ocb_block_xor(in, pad.c, last_len, out);
|
|
|
|
/* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */
|
|
memset(pad.c, 0, 16); /* borrow pad */
|
|
memcpy(pad.c, in, last_len);
|
|
pad.c[last_len] = 0x80;
|
|
ocb_block16_xor(&pad, &ctx->sess.checksum, &ctx->sess.checksum);
|
|
}
|
|
|
|
ctx->sess.blocks_processed = all_num_blocks;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Provide any data to be decrypted. This can be called multiple times. Only
|
|
* the final time can have a partial block
|
|
*/
|
|
int CRYPTO_ocb128_decrypt(OCB128_CONTEXT *ctx,
|
|
const unsigned char *in, unsigned char *out,
|
|
size_t len)
|
|
{
|
|
u64 i, all_num_blocks;
|
|
size_t num_blocks, last_len;
|
|
|
|
/*
|
|
* Calculate the number of blocks of data to be decrypted provided now, and
|
|
* so far
|
|
*/
|
|
num_blocks = len / 16;
|
|
all_num_blocks = num_blocks + ctx->sess.blocks_processed;
|
|
|
|
if (num_blocks && all_num_blocks == (size_t)all_num_blocks
|
|
&& ctx->stream != NULL) {
|
|
size_t max_idx = 0, top = (size_t)all_num_blocks;
|
|
|
|
/*
|
|
* See how many L_{i} entries we need to process data at hand
|
|
* and pre-compute missing entries in the table [if any]...
|
|
*/
|
|
while (top >>= 1)
|
|
max_idx++;
|
|
if (ocb_lookup_l(ctx, max_idx) == NULL)
|
|
return 0;
|
|
|
|
ctx->stream(in, out, num_blocks, ctx->keydec,
|
|
(size_t)ctx->sess.blocks_processed + 1, ctx->sess.offset.c,
|
|
(const unsigned char (*)[16])ctx->l, ctx->sess.checksum.c);
|
|
} else {
|
|
OCB_BLOCK tmp;
|
|
|
|
/* Loop through all full blocks to be decrypted */
|
|
for (i = ctx->sess.blocks_processed + 1; i <= all_num_blocks; i++) {
|
|
|
|
/* Offset_i = Offset_{i-1} xor L_{ntz(i)} */
|
|
OCB_BLOCK *lookup = ocb_lookup_l(ctx, ocb_ntz(i));
|
|
if (lookup == NULL)
|
|
return 0;
|
|
ocb_block16_xor(&ctx->sess.offset, lookup, &ctx->sess.offset);
|
|
|
|
memcpy(tmp.c, in, 16);
|
|
in += 16;
|
|
|
|
/* P_i = Offset_i xor DECIPHER(K, C_i xor Offset_i) */
|
|
ocb_block16_xor(&ctx->sess.offset, &tmp, &tmp);
|
|
ctx->decrypt(tmp.c, tmp.c, ctx->keydec);
|
|
ocb_block16_xor(&ctx->sess.offset, &tmp, &tmp);
|
|
|
|
/* Checksum_i = Checksum_{i-1} xor P_i */
|
|
ocb_block16_xor(&tmp, &ctx->sess.checksum, &ctx->sess.checksum);
|
|
|
|
memcpy(out, tmp.c, 16);
|
|
out += 16;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if we have any partial blocks left over. This is only valid in the
|
|
* last call to this function
|
|
*/
|
|
last_len = len % 16;
|
|
|
|
if (last_len > 0) {
|
|
OCB_BLOCK pad;
|
|
|
|
/* Offset_* = Offset_m xor L_* */
|
|
ocb_block16_xor(&ctx->sess.offset, &ctx->l_star, &ctx->sess.offset);
|
|
|
|
/* Pad = ENCIPHER(K, Offset_*) */
|
|
ctx->encrypt(ctx->sess.offset.c, pad.c, ctx->keyenc);
|
|
|
|
/* P_* = C_* xor Pad[1..bitlen(C_*)] */
|
|
ocb_block_xor(in, pad.c, last_len, out);
|
|
|
|
/* Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*))) */
|
|
memset(pad.c, 0, 16); /* borrow pad */
|
|
memcpy(pad.c, out, last_len);
|
|
pad.c[last_len] = 0x80;
|
|
ocb_block16_xor(&pad, &ctx->sess.checksum, &ctx->sess.checksum);
|
|
}
|
|
|
|
ctx->sess.blocks_processed = all_num_blocks;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int ocb_finish(OCB128_CONTEXT *ctx, unsigned char *tag, size_t len,
|
|
int write)
|
|
{
|
|
OCB_BLOCK tmp;
|
|
|
|
if (len > 16 || len < 1) {
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Tag = ENCIPHER(K, Checksum_* xor Offset_* xor L_$) xor HASH(K,A)
|
|
*/
|
|
ocb_block16_xor(&ctx->sess.checksum, &ctx->sess.offset, &tmp);
|
|
ocb_block16_xor(&ctx->l_dollar, &tmp, &tmp);
|
|
ctx->encrypt(tmp.c, tmp.c, ctx->keyenc);
|
|
ocb_block16_xor(&tmp, &ctx->sess.sum, &tmp);
|
|
|
|
if (write) {
|
|
memcpy(tag, &tmp, len);
|
|
return 1;
|
|
} else {
|
|
return CRYPTO_memcmp(&tmp, tag, len);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Calculate the tag and verify it against the supplied tag
|
|
*/
|
|
int CRYPTO_ocb128_finish(OCB128_CONTEXT *ctx, const unsigned char *tag,
|
|
size_t len)
|
|
{
|
|
return ocb_finish(ctx, (unsigned char*)tag, len, 0);
|
|
}
|
|
|
|
/*
|
|
* Retrieve the calculated tag
|
|
*/
|
|
int CRYPTO_ocb128_tag(OCB128_CONTEXT *ctx, unsigned char *tag, size_t len)
|
|
{
|
|
return ocb_finish(ctx, tag, len, 1);
|
|
}
|
|
|
|
/*
|
|
* Release all resources
|
|
*/
|
|
void CRYPTO_ocb128_cleanup(OCB128_CONTEXT *ctx)
|
|
{
|
|
if (ctx) {
|
|
OPENSSL_clear_free(ctx->l, ctx->max_l_index * 16);
|
|
OPENSSL_cleanse(ctx, sizeof(*ctx));
|
|
}
|
|
}
|
|
|
|
#endif /* OPENSSL_NO_OCB */
|