support: Report NULL blobs explicitly in TEST_COMPARE

Provide an explicit diagnostic if the length is positive, and
do not just crash with a null pointer dereference.  Null pointers
are only valid if the length is zero, so this can only happen with
a faulty test.

1 files changed, 5 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index ea7b3d4f48..0f6ee3ec8e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-16  Florian Weimer  <fweimer@redhat.com>
+
+	* support/support_test_compare_blob.c (report_blob): Report
+	incorrect NULL blobs.
+
 2019-05-15  Mark Wielaard  <mark@klomp.org>
 
 	[BZ# 24476]