Merge remote-tracking branch 'public/pr/1161' into mbedtls-1.3

* public/pr/1161:
  Address PR review comments
  Backport 1.3:Fix crash when calling `mbedtls_ssl_cache_free` twice
diff --git a/ChangeLog b/ChangeLog
index 70a003d..20bb1e3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -38,6 +38,8 @@
    * Add a check for invalid private parameters in ecdsa_sign.
      Reported by Yolan Romailler.
    * Fix word size check in in pk.c to not depend on MBEDTLS_HAVE_INT64.
+   * Fix crash when calling mbedtls_ssl_cache_free() twice. Found by
+     MilenkoMitrovic, #1104
 
 Changes
    * Extend cert_write example program by options to set the CRT version
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 0c2df29..0cad148 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -324,6 +324,8 @@
 #if defined(POLARSSL_THREADING_C)
     polarssl_mutex_free( &cache->mutex );
 #endif
+
+    cache->chain = NULL;
 }
 
 #endif /* POLARSSL_SSL_CACHE_C */