Adapt ChangeLog: Usage restriction for WANT_READ
diff --git a/ChangeLog b/ChangeLog
index 50fefac..6b0fe3b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,15 @@
= mbed TLS x.x.x branch released xxxx-xx-xx
+Bugfix
+ * Restrict usage of error code MBEDTLS_ERR_SSL_WANT_READ to situations
+ where data needs to be fetched from the underlying transport in order
+ to make progress. Previously, this error code was also occasionally
+ returned when unexpected messages were being discarded, ignoring that
+ further messages could potentially already be pending to be processed
+ in the internal buffers; these cases lead to deadlocks in case
+ event-driven I/O was used. Found by Hubert Mis.
+
API changes
* Add function mbedtls_net_poll to public API allowing to wait for a
network context to become ready for reading or writing.