From: Tobias Brunner <tobias@strongswan.org>
Date: Wed, 10 Feb 2021 16:55:06 +0000 (+0100)
Subject: openssl: Allocate our own buffer for i2d_* wrapper macro
X-Git-Tag: 5.9.2dr2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=781ad0b93b13c9e7234d2f86711e3aaf8fce38c3;p=thirdparty%2Fstrongswan.git

openssl: Allocate our own buffer for i2d_* wrapper macro

If we pass a pointer to NULL, the memory allocated by OpenSSL has to be
freed with OPENSSL_free().  Otherwise, this can lead to random
crashes/freezes for Windows builds as seen on AppVeyor.  To not
complicate things for callers of this macro, we allocate our own memory,
which we already do for other i2d_* calls.
---

diff --git a/src/libstrongswan/plugins/openssl/openssl_util.h b/src/libstrongswan/plugins/openssl/openssl_util.h
index eb2a3788bb..f226fef0e4 100644
--- a/src/libstrongswan/plugins/openssl/openssl_util.h
+++ b/src/libstrongswan/plugins/openssl/openssl_util.h
@@ -101,9 +101,14 @@ bool openssl_bn2chunk(const BIGNUM *bn, chunk_t *chunk);
  * @returns			allocated chunk of the object, or chunk_empty
  */
 #define openssl_i2chunk(type, obj) ({ \
-					unsigned char *ptr = NULL; \
-					int len = i2d_##type(obj, &ptr); \
-					len < 0 ? chunk_empty : chunk_create(ptr, len);})
+					chunk_t chunk = chunk_empty; \
+					int len = i2d_##type(obj, NULL); \
+					if (len >= 0) { \
+						chunk = chunk_alloc(len); \
+						u_char *p = chunk.ptr; \
+						i2d_##type(obj, &p); \
+					} \
+					chunk; })
 
 /**
  * Convert an OpenSSL ASN1_OBJECT to a chunk.