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Merge pull request #76 from glebfm/openssl_1_1_0-grasshopper-ctr-ofb-…
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…fixes

Backport grasshopper-ctr and grasshopper-ofb fixes to 1.1.0 branch
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@beldmit
beldmit authored Aug 21, 2018
2 parents 4b7d6a5 + ed191fe commit bad240e
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Showing 2 changed files with 39 additions and 59 deletions.
95 changes: 39 additions & 56 deletions gost_grasshopper_cipher.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,10 @@ static struct GRASSHOPPER_CIPHER_PARAMS gost_cipher_params[5] = {
gost_grasshopper_cipher_destroy_ctr,
1,
sizeof(gost_grasshopper_cipher_ctx_ctr),
8,
/* IV size is set to match full block, to make it responsibility of
* user to assign correct values (IV || 0), and to make naive context
* copy possible (for software such as openssh) */
16,
false
},
};
Expand Down Expand Up @@ -136,10 +139,7 @@ static GRASSHOPPER_INLINE void gost_grasshopper_cipher_destroy_ofb(gost_grasshop
static GRASSHOPPER_INLINE void gost_grasshopper_cipher_destroy_ctr(gost_grasshopper_cipher_ctx* c) {
gost_grasshopper_cipher_ctx_ctr* ctx = (gost_grasshopper_cipher_ctx_ctr*) c;

grasshopper_zero128(&ctx->iv_buffer);
grasshopper_zero128(&ctx->partial_buffer);

ctx->counter = 0;
}

int gost_grasshopper_cipher_init(EVP_CIPHER_CTX* ctx, const unsigned char* key,
Expand Down Expand Up @@ -210,12 +210,10 @@ GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctr(EVP_CIPHER_CTX* ctx, con
gost_grasshopper_cipher_ctx_ctr* c = EVP_CIPHER_CTX_get_cipher_data(ctx);

c->c.type = GRASSHOPPER_CIPHER_CTR;
EVP_CIPHER_CTX_set_num(ctx, 0);

grasshopper_zero128(&c->iv_buffer);
grasshopper_zero128(&c->partial_buffer);

c->counter = 0;

return gost_grasshopper_cipher_init(ctx, key, iv, enc);
}

Expand Down Expand Up @@ -283,28 +281,50 @@ int gost_grasshopper_cipher_do_cbc(EVP_CIPHER_CTX* ctx, unsigned char* out,
return 1;
}

/* increment counter (128-bit int) by 1 */
static void ctr128_inc(unsigned char *counter)
{
unsigned int n = 16;
unsigned char c;

do {
--n;
c = counter[n];
++c;
counter[n] = c;
if (c) return;
} while (n);
}

int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out,
const unsigned char* in, size_t inl) {
gost_grasshopper_cipher_ctx_ctr* c = (gost_grasshopper_cipher_ctx_ctr*) EVP_CIPHER_CTX_get_cipher_data(ctx);
unsigned char* iv = EVP_CIPHER_CTX_iv_noconst(ctx);
const unsigned char* current_in = in;
unsigned char* current_out = out;
size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
grasshopper_w128_t* currentInputBlock;
grasshopper_w128_t* currentOutputBlock;
unsigned int n = EVP_CIPHER_CTX_num(ctx);
size_t lasted;
size_t i;

memcpy(&c->iv_buffer, iv, 8);
while (n && inl) {
*(current_out++) = *(current_in++) ^ c->partial_buffer.b[n];
--inl;
n = (n + 1) % GRASSHOPPER_BLOCK_SIZE;
}
EVP_CIPHER_CTX_set_num(ctx, n);
size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;

grasshopper_w128_t* iv_buffer = (grasshopper_w128_t*) iv;

// full parts
for (i = 0; i < blocks; i++) {
currentInputBlock = (grasshopper_w128_t*) current_in;
currentOutputBlock = (grasshopper_w128_t*) current_out;
memcpy(c->iv_buffer.b + 8, &c->counter, 8);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, &c->iv_buffer, currentOutputBlock, &c->c.buffer);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer, currentOutputBlock, &c->c.buffer);
grasshopper_append128(currentOutputBlock, currentInputBlock);
c->counter += 1;
ctr128_inc(iv_buffer->b);
current_in += GRASSHOPPER_BLOCK_SIZE;
current_out += GRASSHOPPER_BLOCK_SIZE;
}
Expand All @@ -314,62 +334,25 @@ int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out,
if (lasted > 0) {
currentInputBlock = (grasshopper_w128_t*) current_in;
currentOutputBlock = (grasshopper_w128_t*) current_out;
memcpy(c->iv_buffer.b + 8, &c->counter, 8);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, &c->iv_buffer, &c->partial_buffer, &c->c.buffer);
grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer, &c->partial_buffer, &c->c.buffer);
for (i = 0; i < lasted; i++) {
currentOutputBlock->b[i] = c->partial_buffer.b[i] ^ currentInputBlock->b[i];
}
c->counter += 1;
EVP_CIPHER_CTX_set_num(ctx, i);
ctr128_inc(iv_buffer->b);
}

return 1;
}

/*
* Fixed 128-bit IV implementation make shift regiser redundant.
*/
static void gost_grasshopper_cnt_next(gost_grasshopper_cipher_ctx_ofb* ctx, grasshopper_w128_t* iv,
grasshopper_w128_t* buf) {
memcpy(&ctx->buffer1, iv, 16);
ctx->g = ctx->buffer1.b[0] | (ctx->buffer1.b[1] << 8) | (ctx->buffer1.b[2] << 16) |
((uint32_t) ctx->buffer1.b[3] << 24);
ctx->g += 0x01010101;
ctx->buffer1.b[0] = (unsigned char) (ctx->g & 0xff);
ctx->buffer1.b[1] = (unsigned char) ((ctx->g >> 8) & 0xff);
ctx->buffer1.b[2] = (unsigned char) ((ctx->g >> 16) & 0xff);
ctx->buffer1.b[3] = (unsigned char) ((ctx->g >> 24) & 0xff);
ctx->g = ctx->buffer1.b[4] | (ctx->buffer1.b[5] << 8) | (ctx->buffer1.b[6] << 16) |
((uint32_t) ctx->buffer1.b[7] << 24);
ctx->go = ctx->g;
ctx->g += 0x01010104;
if (ctx->go > ctx->g) { /* overflow */
ctx->g++;
}
ctx->buffer1.b[4] = (unsigned char) (ctx->g & 0xff);
ctx->buffer1.b[5] = (unsigned char) ((ctx->g >> 8) & 0xff);
ctx->buffer1.b[6] = (unsigned char) ((ctx->g >> 16) & 0xff);
ctx->buffer1.b[7] = (unsigned char) ((ctx->g >> 24) & 0xff);
ctx->g = ctx->buffer1.b[8] | (ctx->buffer1.b[9] << 8) | (ctx->buffer1.b[10] << 16) |
((uint32_t) ctx->buffer1.b[11] << 24);
ctx->go = ctx->g;
ctx->g += 0x01010107;
if (ctx->go > ctx->g) { /* overflow */
ctx->g++;
}
ctx->buffer1.b[8] = (unsigned char) (ctx->g & 0xff);
ctx->buffer1.b[9] = (unsigned char) ((ctx->g >> 8) & 0xff);
ctx->buffer1.b[10] = (unsigned char) ((ctx->g >> 16) & 0xff);
ctx->buffer1.b[11] = (unsigned char) ((ctx->g >> 24) & 0xff);
ctx->g = ctx->buffer1.b[12] | (ctx->buffer1.b[13] << 8) | (ctx->buffer1.b[14] << 16) |
((uint32_t) ctx->buffer1.b[15] << 24);
ctx->go = ctx->g;
ctx->g += 0x01010110;
if (ctx->go > ctx->g) { /* overflow */
ctx->g++;
}
ctx->buffer1.b[12] = (unsigned char) (ctx->g & 0xff);
ctx->buffer1.b[13] = (unsigned char) ((ctx->g >> 8) & 0xff);
ctx->buffer1.b[14] = (unsigned char) ((ctx->g >> 16) & 0xff);
ctx->buffer1.b[15] = (unsigned char) ((ctx->g >> 24) & 0xff);
memcpy(iv, &ctx->buffer1, 16);
grasshopper_encrypt_block(&ctx->c.encrypt_round_keys, &ctx->buffer1, buf, &ctx->c.buffer);
memcpy(iv, buf, 16);
}

int gost_grasshopper_cipher_do_ofb(EVP_CIPHER_CTX* ctx, unsigned char* out,
Expand Down
3 changes: 0 additions & 3 deletions gost_grasshopper_cipher.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,13 +27,10 @@ typedef struct {
typedef struct {
gost_grasshopper_cipher_ctx c;
grasshopper_w128_t buffer1;
uint32_t g;
uint32_t go;
} gost_grasshopper_cipher_ctx_ofb;

typedef struct {
gost_grasshopper_cipher_ctx c;
grasshopper_w128_t iv_buffer;
grasshopper_w128_t partial_buffer;
uint64_t counter;
} gost_grasshopper_cipher_ctx_ctr;
Expand Down

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