From bb6ecc6d127525e219bd52f088338bd8de903206 Mon Sep 17 00:00:00 2001
From: miod <>
Date: Sun, 13 Jul 2014 11:14:02 +0000
Subject: EVP_DigestInit_ex() may be used to recycle an existing EVP_MD_CTX
 without having to reinitialize all of it, especially if it is used with the
 same MD algorithm.

However, when the MD algorithm changes, it needs to perform more cleanups.
Make that code more closer to what EVP_MD_CTX_cleanup() does by:
- only freeing md_data if EVP_MD_CTX_FLAG_REUSE is not set
- performing an explicit_bzero of md_data before freeing it
- making sure we call EVP_PKEY_CTX_free on the pctx if the allocation for the
  new md_data fails.

ok tedu@
---
 src/lib/libcrypto/evp/digest.c         | 12 +++++++++---
 src/lib/libssl/src/crypto/evp/digest.c | 12 +++++++++---
 2 files changed, 18 insertions(+), 6 deletions(-)

(limited to 'src')

diff --git a/src/lib/libcrypto/evp/digest.c b/src/lib/libcrypto/evp/digest.c
index d582d7954e..a1be18ee22 100644
--- a/src/lib/libcrypto/evp/digest.c
+++ b/src/lib/libcrypto/evp/digest.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: digest.c,v 1.22 2014/07/12 16:03:37 miod Exp $ */
+/* $OpenBSD: digest.c,v 1.23 2014/07/13 11:14:02 miod Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -192,13 +192,19 @@ EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
 	}
 #endif
 	if (ctx->digest != type) {
-		if (ctx->digest && ctx->digest->ctx_size)
+		if (ctx->digest && ctx->digest->ctx_size && ctx->md_data &&
+		    !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE)) {
+			explicit_bzero(ctx->md_data, ctx->digest->ctx_size);
 			free(ctx->md_data);
+			ctx->md_data = NULL;
+		}
 		ctx->digest = type;
 		if (!(ctx->flags & EVP_MD_CTX_FLAG_NO_INIT) && type->ctx_size) {
 			ctx->update = type->update;
 			ctx->md_data = malloc(type->ctx_size);
 			if (ctx->md_data == NULL) {
+				EVP_PKEY_CTX_free(ctx->pctx);
+				ctx->pctx = NULL;
 				EVPerr(EVP_F_EVP_DIGESTINIT_EX,
 				    ERR_R_MALLOC_FAILURE);
 				return 0;
@@ -355,7 +361,7 @@ EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
 		ctx->digest->cleanup(ctx);
 	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);
+		explicit_bzero(ctx->md_data, ctx->digest->ctx_size);
 		free(ctx->md_data);
 	}
 	EVP_PKEY_CTX_free(ctx->pctx);
diff --git a/src/lib/libssl/src/crypto/evp/digest.c b/src/lib/libssl/src/crypto/evp/digest.c
index d582d7954e..a1be18ee22 100644
--- a/src/lib/libssl/src/crypto/evp/digest.c
+++ b/src/lib/libssl/src/crypto/evp/digest.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: digest.c,v 1.22 2014/07/12 16:03:37 miod Exp $ */
+/* $OpenBSD: digest.c,v 1.23 2014/07/13 11:14:02 miod Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -192,13 +192,19 @@ EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
 	}
 #endif
 	if (ctx->digest != type) {
-		if (ctx->digest && ctx->digest->ctx_size)
+		if (ctx->digest && ctx->digest->ctx_size && ctx->md_data &&
+		    !EVP_MD_CTX_test_flags(ctx, EVP_MD_CTX_FLAG_REUSE)) {
+			explicit_bzero(ctx->md_data, ctx->digest->ctx_size);
 			free(ctx->md_data);
+			ctx->md_data = NULL;
+		}
 		ctx->digest = type;
 		if (!(ctx->flags & EVP_MD_CTX_FLAG_NO_INIT) && type->ctx_size) {
 			ctx->update = type->update;
 			ctx->md_data = malloc(type->ctx_size);
 			if (ctx->md_data == NULL) {
+				EVP_PKEY_CTX_free(ctx->pctx);
+				ctx->pctx = NULL;
 				EVPerr(EVP_F_EVP_DIGESTINIT_EX,
 				    ERR_R_MALLOC_FAILURE);
 				return 0;
@@ -355,7 +361,7 @@ EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
 		ctx->digest->cleanup(ctx);
 	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);
+		explicit_bzero(ctx->md_data, ctx->digest->ctx_size);
 		free(ctx->md_data);
 	}
 	EVP_PKEY_CTX_free(ctx->pctx);
-- 
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