Backport 2.1: check if iv is zero in gcm.
1) found by roberto in mbedtls forum
2) if iv_len is zero, return an error
3) add tests for invalid parameters
diff --git a/ChangeLog b/ChangeLog
index 47ede8d..ad3b4de 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,12 @@
mbed TLS ChangeLog (Sorted per branch, date)
-= mbed TLS 2.1.8 released 2017-06-21
+= mbed TLS 2.1.9 branch released xxxx-xx-xx
+
+Bugfix
+ * Add a check if iv_len is zero, and return an error if it is zero. reported
+ by roberto. #716
+
+= mbed TLS 2.1.8 branch released 2017-06-21
Security
* Fixed unlimited overread of heap-based buffer in mbedtls_ssl_read().