Fix mbed TLS key exporter functionality in 3.6.x and cmake

Cmake did not check for the mbedtls_ssl_set_export_keys_cb symbol
when generating an mbed TLS configuration. This causes no actual
working key exporter to be in the binary.

Also add an explicit #error to catch this situation during compilation.

Change-Id: If38e80e268dc0ee7e57de2c175c5b4db0ce55ed0
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20250425131002.21772-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg31510.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b04adced24359d318e10fc7fbbe94d0327fd5e81..a8fb64b6468f6d605b6e77dbc0764a08846a3eef 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -275,6 +275,7 @@ function(check_mbed_configuration)
     set(CMAKE_REQUIRED_LIBRARIES "mbedtls;mbedx509;mbedcrypto")
     check_symbol_exists(mbedtls_ctr_drbg_update_ret mbedtls/ctr_drbg.h HAVE_MBEDTLS_CTR_DRBG_UPDATE_RET)
     check_symbol_exists(mbedtls_ssl_conf_export_keys_ext_cb mbedtls/ssl.h HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB)
+    check_symbol_exists(mbedtls_ssl_set_export_keys_cb mbedtls/ssl.h HAVE_MBEDTLS_SSL_SET_EXPORT_KEYS_CB)
     check_include_files(psa/crypto.h HAVE_MBEDTLS_PSA_CRYPTO_H)
 endfunction()
 

diff --git a/src/openvpn/ssl_mbedtls.c b/src/openvpn/ssl_mbedtls.c
index e15c39180d11693ee7d44b40d42076c906bc586c..ec3135ac42f8fd828e0735f9cde1b5d78d08cf6b 100644 (file)
--- a/src/openvpn/ssl_mbedtls.c
+++ b/src/openvpn/ssl_mbedtls.c
@@ -253,6 +253,8 @@ mbedtls_ssl_export_keys_cb(void *p_expkey,
     memcpy(cache->master_secret, secret, sizeof(cache->master_secret));
     cache->tls_prf_type = tls_prf_type;
 }
+#else  /* if HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB */
+#error either HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB or HAVE_MBEDTLS_SSL_SET_EXPORT_KEYS_CB must be defined when HAVE_EXPORT_KEYING_MATERIAL is defined
 #endif /* HAVE_MBEDTLS_SSL_CONF_EXPORT_KEYS_EXT_CB */
 
 bool