OMACs implementation. Unfinished.

1 files changed, 258 insertions, 0 deletions

diff --git a/gost_omac.c b/gost_omac.c
new file mode 100644
index 0000000..ad96662
--- /dev/null
+++ b/gost_omac.c
@@ -0,0 +1,258 @@
+#include <string.h>
+#include <openssl/cmac.h>
+#include <openssl/conf.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+
+#include "e_gost_err.h"
+#include "gost_lcl.h"
+
+typedef struct omac_ctx {
+	CMAC_CTX *cmac_ctx;
+	size_t   dgst_size;
+	int      cipher_nid;
+	int      key_set;
+} OMAC_CTX;
+
+#define MAX_GOST_OMAC_SIZE 16
+
+static int omac_init(EVP_MD_CTX *ctx, int cipher_nid)
+{
+    OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+		memset(c, 0, sizeof(OMAC_CTX));
+		c->cipher_nid = cipher_nid;
+		c->key_set    = 0;
+
+		switch(cipher_nid) {
+			case NID_magma_cbc:
+				c->dgst_size = 4;
+			break;
+
+			case NID_grasshopper_cbc:
+				c->dgst_size = 8;
+			break;
+		}
+
+    return 1;
+}
+
+static int magma_imit_init(EVP_MD_CTX *ctx)
+{
+    return omac_init(ctx, NID_magma_cbc);
+}
+
+static int grasshopper_imit_init(EVP_MD_CTX *ctx)
+{
+    return omac_init(ctx, NID_grasshopper_cbc);
+}
+
+static int omac_imit_update(EVP_MD_CTX *ctx, const void *data, size_t count)
+{
+    OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+		if (!c->key_set)
+		{
+        GOSTerr(GOST_F_OMAC_IMIT_UPDATE, GOST_R_MAC_KEY_NOT_SET);
+        return 0;
+		}
+
+		return CMAC_Update(c->cmac_ctx, data, count);
+}
+
+int omac_imit_final(EVP_MD_CTX *ctx, unsigned char *md)
+{
+    OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+		unsigned char mac[MAX_GOST_OMAC_SIZE];
+		size_t mac_size = sizeof(mac);
+
+    if (!c->key_set) {
+        GOSTerr(GOST_F_OMAC_IMIT_FINAL, GOST_R_MAC_KEY_NOT_SET);
+        return 0;
+    }
+
+		CMAC_Final(c->cmac_ctx, mac, &mac_size);
+
+    memcpy(md, mac, c->dgst_size);
+    return 1;
+}
+
+int omac_imit_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from)
+{
+    OMAC_CTX *c_to = EVP_MD_CTX_md_data(to);
+		const OMAC_CTX *c_from = EVP_MD_CTX_md_data(from);
+
+    if (c_from && c_to) {
+			c_to->dgst_size  = c_from->dgst_size;
+			c_to->cipher_nid = c_from->cipher_nid;
+			c_to->key_set    = c_from->key_set;
+    }
+		else
+		{
+			return 0;
+		}
+		return CMAC_CTX_copy(c_to->cmac_ctx, c_from->cmac_ctx);
+}
+
+/* Clean up imit ctx */
+int omac_imit_cleanup(EVP_MD_CTX *ctx)
+{
+    OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+
+		if (c)
+		{
+			CMAC_CTX_free(c->cmac_ctx);
+	    memset(EVP_MD_CTX_md_data(ctx), 0, sizeof(OMAC_CTX));
+		}
+    return 1;
+}
+
+static int omac_key(OMAC_CTX *c, const EVP_CIPHER *cipher, const unsigned char *key, size_t key_size)
+{
+	int ret = 0;
+
+	c->cmac_ctx = CMAC_CTX_new();
+	if (c->cmac_ctx == NULL)
+	{
+		GOSTerr(GOST_F_OMAC_KEY, ERR_R_MALLOC_FAILURE);
+		return 0;
+	}
+
+	ret = CMAC_Init(c->cmac_ctx, key, key_size, cipher, NULL);
+	if (ret > 0)
+	{
+		c->key_set = 1;
+	}
+	return 1;
+}						
+
+int omac_imit_ctrl(EVP_MD_CTX *ctx, int type, int arg, void *ptr)
+{
+    switch (type) {
+    case EVP_MD_CTRL_KEY_LEN:
+        *((unsigned int *)(ptr)) = 32;
+        return 1;
+    case EVP_MD_CTRL_SET_KEY:
+				{
+					OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+					const EVP_CIPHER *cipher = EVP_get_cipherbynid(c->cipher_nid);
+
+					if (cipher == NULL)
+					{
+						GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_CIPHER_NOT_FOUND);
+					}
+
+					if (EVP_MD_meth_get_init(EVP_MD_CTX_md(ctx)) (ctx) <= 0) {
+						GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_MAC_KEY_NOT_SET);
+						return 0;
+					}
+					EVP_MD_CTX_set_flags(ctx, EVP_MD_CTX_FLAG_NO_INIT);
+
+					if (c->key_set)
+					{
+						GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_BAD_ORDER);
+						return 0;
+					}
+
+					if (arg == 0) {
+						struct gost_mac_key *key = (struct gost_mac_key *)ptr;
+						return omac_key(c, cipher, key->key, 32);
+
+					} else if (arg == 32) {
+						return omac_key(c, cipher, ptr, 32);
+					}
+					GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_INVALID_MAC_KEY_SIZE);
+					return 0;
+				}
+    case EVP_MD_CTRL_MAC_LEN:
+        {
+					OMAC_CTX *c = EVP_MD_CTX_md_data(ctx);
+					switch (c->cipher_nid)
+					{
+						case NID_magma_cbc:
+            if (arg < 1 || arg > 8) {
+                GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_INVALID_MAC_SIZE);
+                return 0;
+            }
+            c->dgst_size = arg;
+						break;
+						case NID_grasshopper_cbc:
+            if (arg < 1 || arg > 16) {
+                GOSTerr(GOST_F_OMAC_IMIT_CTRL, GOST_R_INVALID_MAC_SIZE);
+                return 0;
+            }
+            c->dgst_size = arg;
+						break;
+						default:
+						return 0;
+					}
+          return 1;
+        }
+
+    default:
+        return 0;
+    }
+}
+
+static EVP_MD *_hidden_magma_mac_md = NULL;
+
+EVP_MD *magma_omac(void)
+{
+    if (_hidden_magma_mac_md == NULL) {
+        EVP_MD *md;
+
+        if ((md = EVP_MD_meth_new(NID_magma_mac, NID_undef)) == NULL
+            || !EVP_MD_meth_set_result_size(md, 4)
+            || !EVP_MD_meth_set_input_blocksize(md, 8)
+            || !EVP_MD_meth_set_app_datasize(md, sizeof(OMAC_CTX))
+            || !EVP_MD_meth_set_flags(md, 0)
+            || !EVP_MD_meth_set_init(md, magma_imit_init)
+            || !EVP_MD_meth_set_update(md, omac_imit_update)
+            || !EVP_MD_meth_set_final(md, omac_imit_final)
+            || !EVP_MD_meth_set_copy(md, omac_imit_copy)
+            || !EVP_MD_meth_set_cleanup(md, omac_imit_cleanup)
+            || !EVP_MD_meth_set_ctrl(md, omac_imit_ctrl)) {
+            EVP_MD_meth_free(md);
+            md = NULL;
+        }
+       _hidden_magma_mac_md = md;
+    }
+    return _hidden_magma_mac_md;
+}
+
+void magma_omac_destroy(void)
+{
+    EVP_MD_meth_free(_hidden_magma_mac_md);
+    _hidden_magma_mac_md = NULL;
+}
+
+static EVP_MD *_hidden_grasshopper_mac_md = NULL;
+
+EVP_MD *grasshopper_omac(void)
+{
+    if (_hidden_grasshopper_mac_md == NULL) {
+        EVP_MD *md;
+
+        if ((md = EVP_MD_meth_new(NID_grasshopper_mac, NID_undef)) == NULL
+            || !EVP_MD_meth_set_result_size(md, 4)
+            || !EVP_MD_meth_set_input_blocksize(md, 8)
+            || !EVP_MD_meth_set_app_datasize(md, sizeof(OMAC_CTX))
+            || !EVP_MD_meth_set_flags(md, 0)
+            || !EVP_MD_meth_set_init(md, grasshopper_imit_init)
+            || !EVP_MD_meth_set_update(md, omac_imit_update)
+            || !EVP_MD_meth_set_final(md, omac_imit_final)
+            || !EVP_MD_meth_set_copy(md, omac_imit_copy)
+            || !EVP_MD_meth_set_cleanup(md, omac_imit_cleanup)
+            || !EVP_MD_meth_set_ctrl(md, omac_imit_ctrl)) {
+            EVP_MD_meth_free(md);
+            md = NULL;
+        }
+       _hidden_grasshopper_mac_md = md;
+    }
+    return _hidden_grasshopper_mac_md;
+}
+
+void grasshopper_omac_destroy(void)
+{
+    EVP_MD_meth_free(_hidden_grasshopper_mac_md);
+    _hidden_grasshopper_mac_md = NULL;
+}
+