Add a mutex to guard reference counting for tls_config.

This makes libtls more friendly for multithreaded use - otherwise we can
end up with incorrect refcounts and end up freeing when we should not be
(or not freeing when we should be).

ok beck@

1 files changed, 3 insertions, 1 deletions

diff --git a/src/lib/libtls/tls.c b/src/lib/libtls/tls.c
index bf1d9da81e..46ed8180d1 100644
--- a/src/lib/libtls/tls.c
+++ b/src/lib/libtls/tls.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.c,v 1.82 2018/11/29 14:24:23 tedu Exp $ */
+/* $OpenBSD: tls.c,v 1.83 2019/04/01 15:58:02 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -256,7 +256,9 @@ tls_configure(struct tls *ctx, struct tls_config *config)
         if (config == NULL)
                 config = tls_config_default;
 
+        pthread_mutex_lock(&config->mutex);
         config->refcount++;
+        pthread_mutex_unlock(&config->mutex);
 
         tls_config_free(ctx->config);