From: Selva Nair <selva.nair@gmail.com>
Date: Sat, 30 Oct 2021 18:57:56 +0000 (-0400)
Subject: Avoid memory leak in hmac_ctx_new (OpenSSL 3.0 only)
X-Git-Tag: v2.6_beta1~395
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31e200f807033ac27566bf37a8d9d32820600a83;p=thirdparty%2Fopenvpn.git

Avoid memory leak in hmac_ctx_new (OpenSSL 3.0 only)

In OpenSSL 3.0, fetched algorithms must be freed
(down referenced). In this case, though EVP_MAC_CTX_new()
keeps a reference to 'hmac', it up-refs it. So we have to free
it here before return.

(Tested using an enable-asan build).

Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20211030185756.1831-1-selva.nair@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23080.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
---

diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index c43d18b9c..8e29a77b4 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -1097,6 +1097,9 @@ hmac_ctx_new(void)
     EVP_MAC *hmac = EVP_MAC_fetch(NULL, "HMAC", NULL);
     ctx->ctx = EVP_MAC_CTX_new(hmac);
     check_malloc_return(ctx->ctx);
+
+    EVP_MAC_free(hmac);
+
     return ctx;
 }