Optimize out skip_sections and add tests for ACPKM-Master

ACPKM-Master is from R 23565.1.017-2018, it will be required for
ACPKM-OMAC for TLS 1.2.

3 files changed, 37 insertions, 24 deletions

diff --git a/gost_grasshopper_cipher.c b/gost_grasshopper_cipher.c
index 528a7ee..e78fae7 100644
--- a/gost_grasshopper_cipher.c
+++ b/gost_grasshopper_cipher.c
@@ -126,9 +126,8 @@ static const unsigned char ACPKM_D_2018[] = {
     0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 256 bit */
 };
 
-static void acpkm_grasshopper(gost_grasshopper_cipher_ctx_ctr *ctx)
+static void acpkm_next(gost_grasshopper_cipher_ctx *c)
 {
-    gost_grasshopper_cipher_ctx *c = &ctx->c;
     unsigned char newkey[GRASSHOPPER_KEY_SIZE];
     const int J = GRASSHOPPER_KEY_SIZE / GRASSHOPPER_BLOCK_SIZE;
     int n;
@@ -265,7 +264,6 @@ GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctracpkm(EVP_CIPHER_CTX *ctx
     c->c.type = GRASSHOPPER_CIPHER_CTRACPKM;
     EVP_CIPHER_CTX_set_num(ctx, 0);
     c->section_size  = 4096;
-    c->skip_sections = 1;
 
     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 }
@@ -403,20 +401,16 @@ int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX* ctx, unsigned char* out,
     return 1;
 }
 
-static inline void apply_acpkm_grasshopper(gost_grasshopper_cipher_ctx_ctr *ctx, unsigned int num)
+#define GRASSHOPPER_BLOCK_MASK (GRASSHOPPER_BLOCK_SIZE - 1)
+static inline void apply_acpkm_grasshopper(gost_grasshopper_cipher_ctx_ctr *ctx, unsigned int *num)
 {
     if (!ctx->section_size ||
-        (num & (ctx->section_size - 1)))
-        return;
-    if (ctx->skip_sections) {
-        /* In no master key mode first section is using original key */
-        --ctx->skip_sections;
+        (*num < ctx->section_size))
         return;
-    }
-    acpkm_grasshopper(ctx);
+    acpkm_next(&ctx->c);
+    *num &= GRASSHOPPER_BLOCK_MASK;
 }
 
-#define GRASSHOPPER_BLOCK_MASK (GRASSHOPPER_BLOCK_SIZE - 1)
 /* If meshing is not configured via ctrl (setting section_size)
  * this function works exactly like plain ctr */
 int gost_grasshopper_cipher_do_ctracpkm(EVP_CIPHER_CTX *ctx, unsigned char *out,
@@ -435,7 +429,7 @@ int gost_grasshopper_cipher_do_ctracpkm(EVP_CIPHER_CTX *ctx, unsigned char *out,
 
     // full parts
     for (i = 0; i < blocks; i++) {
-        apply_acpkm_grasshopper(c, num);
+        apply_acpkm_grasshopper(c, &num);
         grasshopper_encrypt_block(&c->c.encrypt_round_keys,
             (grasshopper_w128_t *)iv, (grasshopper_w128_t *)out, &c->c.buffer);
         grasshopper_append128((grasshopper_w128_t *)out, (grasshopper_w128_t *)in);
@@ -448,7 +442,7 @@ int gost_grasshopper_cipher_do_ctracpkm(EVP_CIPHER_CTX *ctx, unsigned char *out,
     // last part
     size_t lasted = inl - blocks * GRASSHOPPER_BLOCK_SIZE;
     if (lasted > 0) {
-        apply_acpkm_grasshopper(c, num);
+        apply_acpkm_grasshopper(c, &num);
         grasshopper_encrypt_block(&c->c.encrypt_round_keys,
             (grasshopper_w128_t *)iv, &c->partial_buffer, &c->c.buffer);
         for (i = 0; i < lasted; i++)
@@ -662,11 +656,9 @@ int gost_grasshopper_cipher_ctl(EVP_CIPHER_CTX* ctx, int type, int arg, void* pt
         case EVP_CTRL_KEY_MESH: {
             gost_grasshopper_cipher_ctx_ctr *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
             if (c->c.type != GRASSHOPPER_CIPHER_CTRACPKM ||
-                arg <= 1 ||
-                ((arg - 1) & arg))
+                !arg || (arg % GRASSHOPPER_BLOCK_SIZE))
                 return -1;
             c->section_size = arg;
-            c->skip_sections = 1;
             break;
         }
         default:
diff --git a/gost_grasshopper_cipher.h b/gost_grasshopper_cipher.h
index 0ab17c1..cc67795 100644
--- a/gost_grasshopper_cipher.h
+++ b/gost_grasshopper_cipher.h
@@ -32,7 +32,6 @@ typedef struct {
 typedef struct {
     gost_grasshopper_cipher_ctx c;
     grasshopper_w128_t partial_buffer;
-    unsigned int skip_sections; /* 1 or 0, used to skip meshing for a first section */
     unsigned int section_size;  /* After how much bytes mesh the key,
 				   if 0 never mesh and work like plain ctr. */
 } gost_grasshopper_cipher_ctx_ctr;
diff --git a/test_grasshopper.c b/test_grasshopper.c
index db2c3e1..ab6e200 100644
--- a/test_grasshopper.c
+++ b/test_grasshopper.c
@@ -80,6 +80,20 @@ static const unsigned char E_acpkm[] = {
     0xDF,0xFD,0x07,0xEC,0x81,0x36,0x36,0x46,0x0C,0x4F,0x3B,0x74,0x34,0x23,0x16,0x3E,
     0x64,0x09,0xA9,0xC2,0x82,0xFA,0xC8,0xD4,0x69,0xD2,0x21,0xE7,0xFB,0xD6,0xDE,0x5D,
 };
+/* Test vector from R 23565.1.017-2018 A.4.2.
+ * Key material from ACPKM-Master(K,768,3) for OMAC-ACPKM. */
+static const unsigned char E_acpkm_master[] = {
+    0x0C,0xAB,0xF1,0xF2,0xEF,0xBC,0x4A,0xC1,0x60,0x48,0xDF,0x1A,0x24,0xC6,0x05,0xB2,
+    0xC0,0xD1,0x67,0x3D,0x75,0x86,0xA8,0xEC,0x0D,0xD4,0x2C,0x45,0xA4,0xF9,0x5B,0xAE,
+    0x0F,0x2E,0x26,0x17,0xE4,0x71,0x48,0x68,0x0F,0xC3,0xE6,0x17,0x8D,0xF2,0xC1,0x37,
+    0xC9,0xDD,0xA8,0x9C,0xFF,0xA4,0x91,0xFE,0xAD,0xD9,0xB3,0xEA,0xB7,0x03,0xBB,0x31,
+    0xBC,0x7E,0x92,0x7F,0x04,0x94,0x72,0x9F,0x51,0xB4,0x9D,0x3D,0xF9,0xC9,0x46,0x08,
+    0x00,0xFB,0xBC,0xF5,0xED,0xEE,0x61,0x0E,0xA0,0x2F,0x01,0x09,0x3C,0x7B,0xC7,0x42,
+    0xD7,0xD6,0x27,0x15,0x01,0xB1,0x77,0x77,0x52,0x63,0xC2,0xA3,0x49,0x5A,0x83,0x18,
+    0xA8,0x1C,0x79,0xA0,0x4F,0x29,0x66,0x0E,0xA3,0xFD,0xA8,0x74,0xC6,0x30,0x79,0x9E,
+    0x14,0x2C,0x57,0x79,0x14,0xFE,0xA9,0x0D,0x3B,0xC2,0x50,0x2E,0x83,0x36,0x85,0xD9,
+};
+static const unsigned char P_acpkm_master[sizeof(E_acpkm_master)] = { 0 };
 /*
  * Other modes (ofb, cbc, cfb) is impossible to test to match GOST R
  * 34.13-2015 test vectors exactly, due to these vectors having exceeding
@@ -112,10 +126,14 @@ static const unsigned char E_cfb[] = {
     0xe1,0xc8,0x52,0xe9,0xa8,0x56,0x71,0x62,0xdb,0xb5,0xda,0x7f,0x66,0xde,0xa9,0x26,
 };
 
-static const unsigned char iv_ctr[]	= { 0x12,0x34,0x56,0x78,0x90,0xab,0xce,0xf0, 0,0,0,0,0,0,0,0 };
-/* truncated to 128-bits IV */
+static const unsigned char iv_ctr[]	= { 0x12,0x34,0x56,0x78,0x90,0xab,0xce,0xf0,
+					    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
+/* Truncated to 128-bits IV from GOST examples. */
 static const unsigned char iv_128bit[]	= { 0x12,0x34,0x56,0x78,0x90,0xab,0xce,0xf0,
 					    0xa1,0xb2,0xc3,0xd4,0xe5,0xf0,0x01,0x12 };
+/* Universal IV for ACPKM-Master. */
+static const unsigned char iv_acpkm_m[]	= { 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
+					    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
 struct testcase {
     const char *name;
     const EVP_CIPHER *(*type)(void);
@@ -132,6 +150,8 @@ static struct testcase testcases[] = {
     { "ctr", cipher_gost_grasshopper_ctr, 1, P,  E_ctr,  sizeof(P),  iv_ctr,     sizeof(iv_ctr), 0 },
     { "ctr-no-acpkm", cipher_gost_grasshopper_ctracpkm, 1, P,   E_ctr,   sizeof(P),       iv_ctr, sizeof(iv_ctr), 0 },
     { "ctracpkm", cipher_gost_grasshopper_ctracpkm, 1, P_acpkm, E_acpkm, sizeof(P_acpkm), iv_ctr, sizeof(iv_ctr), 256 / 8 },
+    { "acpkm-Master", cipher_gost_grasshopper_ctracpkm, 0, P_acpkm_master, E_acpkm_master, sizeof(P_acpkm_master),
+	iv_acpkm_m, sizeof(iv_acpkm_m), 768 / 8 },
     { "ofb", cipher_gost_grasshopper_ofb, 1, P,  E_ofb,  sizeof(P),  iv_128bit,  sizeof(iv_128bit), 0 },
     { "cbc", cipher_gost_grasshopper_cbc, 0, P,  E_cbc,  sizeof(P),  iv_128bit,  sizeof(iv_128bit), 0 },
     { "cfb", cipher_gost_grasshopper_cfb, 0, P,  E_cfb,  sizeof(P),  iv_128bit,  sizeof(iv_128bit), 0 },
@@ -155,12 +175,13 @@ static int test_block(const EVP_CIPHER *type, const char *name,
     const unsigned char *iv, size_t iv_size, int acpkm)
 {
     EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+    const char *standard = acpkm? "R 23565.1.017-2018" : "GOST R 34.13-2015";
     unsigned char c[size];
     int outlen, tmplen;
     int ret = 0, test;
 
     OPENSSL_assert(ctx);
-    printf("Encryption test from GOST R 34.13-2015 [%s] \n", name);
+    printf("Encryption test from %s [%s] \n", standard, name);
     /* test with single big chunk */
     EVP_CIPHER_CTX_init(ctx);
     T(EVP_CipherInit_ex(ctx, type, NULL, K, iv, 1));
@@ -178,7 +199,7 @@ static int test_block(const EVP_CIPHER *type, const char *name,
     ret |= test;
 
     /* test with small chunks of block size */
-    printf("Chunked encryption test from GOST R 34.13-2015 [%s] \n", name);
+    printf("Chunked encryption test from %s [%s] \n", standard, name);
     int blocks = size / GRASSHOPPER_BLOCK_SIZE;
     int z;
     EVP_CIPHER_CTX_init(ctx);
@@ -203,7 +224,7 @@ static int test_block(const EVP_CIPHER *type, const char *name,
     ret |= test;
 
     /* test with single big chunk */
-    printf("Decryption test from GOST R 34.13-2015 [%s] \n", name);
+    printf("Decryption test from %s [%s] \n", standard, name);
     EVP_CIPHER_CTX_init(ctx);
     T(EVP_CipherInit_ex(ctx, type, NULL, K, iv, 0));
     T(EVP_CIPHER_CTX_set_padding(ctx, 0));
@@ -228,12 +249,13 @@ static int test_stream(const EVP_CIPHER *type, const char *name,
     const unsigned char *iv, size_t iv_size, int acpkm)
 {
     EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
+    const char *standard = acpkm? "R 23565.1.017-2018" : "GOST R 34.13-2015";
     int ret = 0, test;
     int z;
 
     OPENSSL_assert(ctx);
     /* Cycle through all lengths from 1 upto maximum size */
-    printf("Stream encryption test from GOST R 34.13-2015 [%s] \n", name);
+    printf("Stream encryption test from %s [%s] \n", standard, name);
     for (z = 1; z <= size; z++) {
 	unsigned char c[size];
 	int outlen, tmplen;