Address review feedback

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/ChangeLog.d/fix_fragment_len_return.txt b/ChangeLog.d/fix_fragment_len_return.txt
new file mode 100644
index 0000000..bfbf93c
--- /dev/null
+++ b/ChangeLog.d/fix_fragment_len_return.txt
@@ -0,0 +1,5 @@
+Bugfix
+   * Fix the error returned when a client requests an invalid
+   * fragment length, as per RFC6066 section 4. We now return
+   * MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER, and raise the corresponding
+   * alert.
diff --git a/ChangeLog.d/update_ssl_error_codes.txt b/ChangeLog.d/update_ssl_error_codes.txt
new file mode 100644
index 0000000..0630b54
--- /dev/null
+++ b/ChangeLog.d/update_ssl_error_codes.txt
@@ -0,0 +1,3 @@
+Changes
+   * Various changes to which alert and/or error code may be returned
+   * during the TLS handshake.