From: Vitaly Chikunov <vt@altlinux.org>
Date: Wed, 1 Aug 2018 21:03:06 +0000 (+0300)
Subject: Fix EVP_MD_CTX_copy_ex for OMAC
X-Git-Tag: v3.0.0~387
X-Git-Url: http://wagner.pp.ru/gitweb/?a=commitdiff_plain;h=636dd0c1f36872f0abcb4f8a465e837929ed19d1;p=openssl-gost%2Fengine.git

Fix EVP_MD_CTX_copy_ex for OMAC

Openssl copies a state between valid contexts. But, EVP_MD_CTX_copy_ex
just memcpy-s private data (md_data), which points to OMAC_CTX), which
have pointer to CMAC_CTX. Copying pointer makes CMAC context just the
same on the both sides. As a consequence, we can not do normal copy of a
state between CMAC contexts. As a fix, we just clone it if it's equal
between copy sides.

Reported-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
---

diff --git a/gost_omac.c b/gost_omac.c
index c4e8111..af6eb2a 100644
--- a/gost_omac.c
+++ b/gost_omac.c
@@ -91,7 +91,7 @@ int omac_imit_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from)
 		}
 		if (c_to->cmac_ctx == c_from->cmac_ctx)
 		{
-			return 1;
+		    c_to->cmac_ctx = CMAC_CTX_new();
 		}
 		return CMAC_CTX_copy(c_to->cmac_ctx, c_from->cmac_ctx);
 }