Add flag to avoid continuous

memory allocate when calling EVP_MD_CTX_copy_ex().

Without this HMAC is several times slower than
< 0.9.7.

CHANGES

@@ -617,6 +617,12 @@
 
  Changes between 0.9.7c and 0.9.7d  [xx XXX XXXX]
 
+  *) New md flag EVP_MD_CTX_FLAG_REUSE this allows md_data to be reused when
+     calling EVP_MD_CTX_copy_ex() to avoid calling OPENSSL_malloc(). Without
+     this HMAC (and other) operations are several times slower than OpenSSL
+     < 0.9.7.
+     [Steve Henson]
+
   *) Print out GeneralizedTime and UTCTime in ASN1_STRING_print_ex().
      [Peter Sylvester <Peter.Sylvester@EdelWeb.fr>]
 

crypto/evp/digest.c

@@ -248,6 +248,7 @@ int EVP_MD_CTX_copy(EVP_MD_CTX *out, const EVP_MD_CTX *in)
 
 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in)
 	{
+	unsigned char *tmp_buf;
 	if ((in == NULL) || (in->digest == NULL))
 		{
 		EVPerr(EVP_F_EVP_MD_CTX_COPY,EVP_R_INPUT_NOT_INITIALIZED);
@@ -262,15 +263,22 @@ int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in)
 		}
 #endif
 
+	if (out->digest == in->digest)
+		{
+		tmp_buf = out->md_data;
+	    	EVP_MD_CTX_set_flags(out,EVP_MD_CTX_FLAG_REUSE);
+		}
+	else tmp_buf = NULL;
 	EVP_MD_CTX_cleanup(out);
 	memcpy(out,in,sizeof *out);
 
 	if (out->digest->ctx_size)
 		{
-		out->md_data=OPENSSL_malloc(out->digest->ctx_size);
+		if (tmp_buf) out->md_data = tmp_buf;
+		else out->md_data=OPENSSL_malloc(out->digest->ctx_size);
 		memcpy(out->md_data,in->md_data,out->digest->ctx_size);
 		}
-	
+
 	if (out->digest->copy)
 		return out->digest->copy(out,in);
 	
@@ -308,7 +316,8 @@ int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
 	if (ctx->digest && ctx->digest->cleanup
 	    && !EVP_MD_CTX_test_flags(ctx,EVP_MD_CTX_FLAG_CLEANED))
 		ctx->digest->cleanup(ctx);
-	if (ctx->digest && ctx->digest->ctx_size && ctx->md_data)
+	if (ctx->digest && ctx->digest->ctx_size && ctx->md_data
+	    && !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE))
 		{
 		OPENSSL_cleanse(ctx->md_data,ctx->digest->ctx_size);
 		OPENSSL_free(ctx->md_data);

crypto/evp/evp.h

@@ -288,6 +288,8 @@ struct env_md_ctx_st
 						* once only */
 #define EVP_MD_CTX_FLAG_CLEANED		0x0002 /* context has already been
 						* cleaned */
+#define EVP_MD_CTX_FLAG_REUSE		0x0004 /* Don't free up ctx->md_data
+						* in EVP_MD_CTX_cleanup */
 
 struct evp_cipher_st
 	{