commit f0cb848908147d3791745297d9901a638c47e065
author Wan-Teh Chang <wtc@google.com> Sat Nov 07 12:26:50 2020 -0800
committer Joe Drago <joedrago@gmail.com> Mon Nov 09 12:27:34 2020 -0800
tree 0402c1a69e20b91dc63239db3dda026e46589d3a
parent cff2a6411eaa1201cfab11624b3e667193a98fab

Reorder the offset checks in avifIOTestReaderRead

Perform the offset checks in the same order as the comments for
avifIOReadFunc in avif.h.

tests/aviftest.c

diff --git a/tests/aviftest.c b/tests/aviftest.c
index 861f8e7..770dd6a 100644
--- a/tests/aviftest.c
+++ b/tests/aviftest.c
@@ -273,15 +273,15 @@
     avifIOTestReader * reader = (avifIOTestReader *)io;
 
     // Sanitize/clamp incoming request
+    if (offset > reader->rodata.size) {
+        // The offset is past the end of the buffer.
+        return AVIF_RESULT_IO_ERROR;
+    }
     if (offset == reader->rodata.size) {
         // The parser is *exactly* at EOF: return a 0-size pointer to any valid buffer
         offset = 0;
         size = 0;
     }
-    if (offset > reader->rodata.size) {
-        // The offset is past the end of the buffer.
-        return AVIF_RESULT_IO_ERROR;
-    }
     uint64_t availableSize = reader->rodata.size - offset;
     if (size > availableSize) {
         size = (size_t)availableSize;