Export keying material using early exporter master secret

This commit adds SSL_export_keying_material_early() which exports
keying material using early exporter master secret.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5252)

1 files changed, 12 insertions, 0 deletions

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 00e02f4dc7..59b507e788 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -2810,6 +2810,18 @@ int SSL_export_keying_material(SSL *s, unsigned char *out, size_t olen,
                                                        contextlen, use_context);
 }
 
+int SSL_export_keying_material_early(SSL *s, unsigned char *out, size_t olen,
+                                     const char *label, size_t llen,
+                                     const unsigned char *context,
+                                     size_t contextlen)
+{
+    if (s->version != TLS1_3_VERSION)
+        return 0;
+
+    return tls13_export_keying_material_early(s, out, olen, label, llen,
+                                              context, contextlen);
+}
+
 static unsigned long ssl_session_hash(const SSL_SESSION *a)
 {
     const unsigned char *session_id = a->session_id;