mbedtls: do not define mbedtls_ctr_drbg_update_ret when not needed

The mbedtls_ctr_drbg_update_ret() function was backported to various
older branches, including 2.14 and 2.7.
To avoid making the #if guard too complex, let's detect if this function
exist at configure time.
All versions not having this function, will use our compat code.

Cc: Max Fillinger <maximilian.fillinger@foxcrypto.com>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Max Fillinger <maximilian.fillinger@foxcrypto.com>
Message-Id: <20210812085300.4738-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22734.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/configure.ac b/configure.ac
index 640ab6faa734d8c1e208c9edf85155275690ef5c..aa632005bdf03c96069ec2ddf61f06afb83df709 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -898,6 +898,12 @@ elif test "${with_crypto_library}" = "mbedtls"; then
                [have_export_keying_material="no"]
        )
 
+       AC_CHECK_FUNC(
+               [mbedtls_ctr_drbg_update_ret],
+               AC_DEFINE([HAVE_CTR_DRBG_UPDATE_RET], [1],
+                         [Use mbedtls_ctr_drbg_update_ret from mbed TLS]),
+       )
+
        CFLAGS="${saved_CFLAGS}"
        LIBS="${saved_LIBS}"
        AC_DEFINE([ENABLE_CRYPTO_MBEDTLS], [1], [Use mbed TLS library])

diff --git a/src/openvpn/ssl_mbedtls.c b/src/openvpn/ssl_mbedtls.c
index 1853335e602490d53f1d5ca9f92d260068990a9d..cea88f41efe4380e471a29efd74ccabe2830fdec 100644 (file)
--- a/src/openvpn/ssl_mbedtls.c
+++ b/src/openvpn/ssl_mbedtls.c
@@ -66,8 +66,11 @@
  * Compatibility: mbedtls_ctr_drbg_update was deprecated in mbedtls 2.16 and
  * replaced with mbedtls_ctr_drbg_update_ret, which returns an error code.
  * For older versions, we call mbedtls_ctr_drbg_update and return 0 (success).
+ *
+ * Note: this change was backported to other mbedTLS branches, therefore we
+ * rely on function detection at configure time.
  */
-#if MBEDTLS_VERSION_NUMBER < 0x02100000
+#ifndef HAVE_CTR_DRBG_UPDATE_RET
 static int mbedtls_ctr_drbg_update_ret(mbedtls_ctr_drbg_context *ctx,
                                        const unsigned char *additional,
                                        size_t add_len)