Add GCM IV generator. Add some FIPS restrictions to GCM. Update fips_gcmtest.

CHANGES

@@ -4,6 +4,10 @@
 
  Changes between 1.0.1 and 1.1.0  [xx XXX xxxx]
 
+  *) Add some FIPS mode restrictions to GCM. Add internal IV generator.
+     Update fips_gcmtest to use IV generator.
+     [Steve Henson]
+
   *) Initial, experimental EVP support for AES-GCM. AAD can be input by
      setting output buffer to NULL. The *Final function must be
      called although it will not retrieve any additional data. The tag

crypto/evp/e_aes.c

@@ -59,6 +59,7 @@
 #include <openssl/aes.h>
 #include "evp_locl.h"
 #include <openssl/modes.h>
+#include <openssl/rand.h>
 
 static int aes_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 					const unsigned char *iv, int enc);
@@ -197,11 +198,15 @@ typedef struct
 	int iv_set;
 	/* Pointer to GCM128_CTX: FIXME actual structure later */
 	GCM128_CONTEXT *gcm;
+	/* Temporary IV store */
+	unsigned char *iv;
 	/* IV length */
 	int ivlen;
 	/* Tag to verify */
 	unsigned char tag[16];
 	int taglen;
+	/* It is OK to generate IVs */
+	int iv_gen;
 	} EVP_AES_GCM_CTX;
 
 static int aes_gcm_cleanup(EVP_CIPHER_CTX *c)
@@ -209,9 +214,25 @@ static int aes_gcm_cleanup(EVP_CIPHER_CTX *c)
 	EVP_AES_GCM_CTX *gctx = c->cipher_data;
 	if (gctx->gcm)
 		CRYPTO_gcm128_release(gctx->gcm);
+	if (gctx->iv != c->iv)
+		OPENSSL_free(gctx->iv);
 	return 1;
 	}
 
+/* increment counter (64-bit int) by 1 */
+static void ctr64_inc(unsigned char *counter) {
+	int n=8;
+	unsigned char  c;
+
+	do {
+		--n;
+		c = counter[n];
+		++c;
+		counter[n] = c;
+		if (c) return;
+	} while (n);
+}
+
 static int aes_gcm_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr)
 	{
 	EVP_AES_GCM_CTX *gctx = c->cipher_data;
@@ -222,12 +243,28 @@ static int aes_gcm_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr)
 		gctx->key_set = 0;
 		gctx->iv_set = 0;
 		gctx->ivlen = c->cipher->iv_len;
+		gctx->iv = c->iv;
 		gctx->taglen = -1;
+		gctx->iv_gen = 0;
 		return 1;
 
 	case EVP_CTRL_GCM_SET_IVLEN:
 		if (arg <= 0)
 			return 0;
+#ifdef OPENSSL_FIPS
+		if (FIPS_mode() && !(c->flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)
+						 && arg < 12)
+			return 0;
+#endif
+		/* Allocate memory for IV if needed */
+		if ((arg > EVP_MAX_IV_LENGTH) && (arg > gctx->ivlen))
+			{
+			if (gctx->iv != c->iv)
+				OPENSSL_free(gctx->iv);
+			gctx->iv = OPENSSL_malloc(arg);
+			if (!gctx->iv)
+				return 0;
+			}
 		gctx->ivlen = arg;
 		return 1;
 
@@ -244,6 +281,39 @@ static int aes_gcm_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr)
 		memcpy(ptr, gctx->tag, arg);
 		return 1;
 
+	case EVP_CTRL_GCM_SET_IV_FIXED:
+		/* Special case: -1 length restores whole IV */
+		if (arg == -1)
+			{
+			memcpy(gctx->iv, ptr, gctx->ivlen);
+			gctx->iv_gen = 1;
+			return 1;
+			}
+		/* Fixed field must be at least 4 bytes and invocation field
+		 * at least 8.
+		 */
+		if ((arg < 4) || (gctx->ivlen - arg) < 8)
+			return 0;
+		if (arg)
+			memcpy(gctx->iv, ptr, arg);
+		if (RAND_bytes(gctx->iv + arg, gctx->ivlen - arg) <= 0)
+			return 0;
+		gctx->iv_gen = 1;
+		return 1;
+
+	case EVP_CTRL_GCM_IV_GEN:
+		if (gctx->iv_gen == 0 || gctx->key_set == 0)
+			return 0;
+		CRYPTO_gcm128_setiv(gctx->gcm, gctx->iv, gctx->ivlen);
+		memcpy(ptr, gctx->iv, gctx->ivlen);
+		/* Invocation field will be at least 8 bytes in size and
+		 * so no need to check wrap around or increment more than
+		 * last 8 bytes.
+		 */
+		ctr64_inc(gctx->iv + gctx->ivlen - 8);
+		gctx->iv_set = 1;
+		return 1;
+
 	default:
 		return -1;
 
@@ -272,7 +342,7 @@ static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 		 * saved IV.
 		 */
 		if (iv == NULL && gctx->iv_set)
-			iv = ctx->iv;
+			iv = gctx->iv;
 		if (iv)
 			{
 			CRYPTO_gcm128_setiv(gctx->gcm, iv, gctx->ivlen);
@@ -286,16 +356,9 @@ static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 		if (gctx->key_set)
 			CRYPTO_gcm128_setiv(gctx->gcm, iv, gctx->ivlen);
 		else
-			{
-			/* If IV is too large for EVP_CIPHER_CTX buffer
-			 * return an error. This can be avoided by either
-			 * setting the key first or key and iv simultaneously.
-			 */
-			if (gctx->ivlen > EVP_MAX_IV_LENGTH)
-				return 0;
-			memcpy(ctx->iv, iv, gctx->ivlen);
-			}
+			memcpy(gctx->iv, iv, gctx->ivlen);
 		gctx->iv_set = 1;
+		gctx->iv_gen = 0;
 		}
 	return 1;
 	}

crypto/evp/evp.h

@@ -374,6 +374,8 @@ struct evp_cipher_st
 #define 	EVP_CTRL_GCM_SET_IVLEN		0x9
 #define 	EVP_CTRL_GCM_GET_TAG		0x10
 #define 	EVP_CTRL_GCM_SET_TAG		0x11
+#define		EVP_CTRL_GCM_SET_IV_FIXED	0x12
+#define		EVP_CTRL_GCM_IV_GEN		0x13
 
 typedef struct evp_cipher_info_st
 	{

fips/aes/fips_gcmtest.c

@@ -172,13 +172,31 @@ static void gcmtest(int encrypt)
 				exit(1);
 				}
 			}
-		/* FIXME: need intenal IV generation */
-		if (encrypt && iv && pt && aad)
+		if (encrypt && pt && aad && (iv || encrypt==1))
 			{
 			tag = OPENSSL_malloc(taglen);
 			EVP_CipherInit_ex(&ctx, gcm, NULL, NULL, NULL, 1);
 			EVP_CIPHER_CTX_ctrl(&ctx, EVP_CTRL_GCM_SET_IVLEN, ivlen, 0);
-			EVP_CipherInit_ex(&ctx, NULL, NULL, key, iv, 1);
+			if (encrypt == 1)
+				{
+				static unsigned char iv_fixed[4] = {1,2,3,4};
+				if (!iv)
+					iv = OPENSSL_malloc(ivlen);
+				EVP_CipherInit_ex(&ctx, NULL, NULL, key, NULL, 1);
+				EVP_CIPHER_CTX_ctrl(&ctx,
+						EVP_CTRL_GCM_SET_IV_FIXED,
+						4, iv_fixed);
+				if (!EVP_CIPHER_CTX_ctrl(&ctx,
+					EVP_CTRL_GCM_IV_GEN, 0, iv))
+					{
+					fprintf(stderr, "IV gen error\n");
+					exit(1);
+					}
+				OutputValue("IV", iv, ivlen, stdout, 0);
+				}
+			else
+				EVP_CipherInit_ex(&ctx, NULL, NULL, key, iv, 1);
+
 
 			if (aadlen)
 				EVP_Cipher(&ctx, NULL, aad, aadlen);
@@ -254,6 +272,8 @@ int main(int argc,char **argv)
 		exit(1);
 	if(!strcmp(argv[1],"-encrypt"))
 		encrypt = 1;
+	else if(!strcmp(argv[1],"-encryptIVext"))
+		encrypt = 2;
 	else if(!strcmp(argv[1],"-decrypt"))
 		encrypt = 0;
 	else