commit c3adf73b6f927ffea62b198f86b35d6c79211e9a
author Wan-Teh Chang <wtc@google.com> Sat Apr 15 07:56:29 2023 -0700
committer Vignesh Venkatasubramanian <vigneshvg@users.noreply.github.com> Tue Apr 18 14:00:09 2023 -0700
tree db979a21e6e60f5b2855e3ab58052a48a3676c18
parent b90e8bbdfe147dfd1b6e565d932f2c835a6165cf

Don't test potentially dangling pointers

In avifDecoderDataCopyTileToImage(), if a shared codec is used to decode
a grid image, the yuvPlanes pointers of firstTile->image will become
invalid when the shared codec decodes the second tile. Although we only
test if the pointers are null and do not dereference them, it is best to
avoid even testing them. Also, the yuvFormat check should cover this
check.

src/read.c

diff --git a/src/read.c b/src/read.c
index a9f17ed..a867223 100644
--- a/src/read.c
+++ b/src/read.c
@@ -1397,12 +1397,9 @@
     const avifTile * firstTile = &data->tiles.tile[info->firstTileIndex];
     if (tile != firstTile) {
         // Check for tile consistency. All tiles in a grid image should match the first tile in the properties checked below.
-        avifBool uvPresent = (tile->image->yuvPlanes[AVIF_CHAN_U] && tile->image->yuvPlanes[AVIF_CHAN_V]);
-        avifBool firstTileUVPresent = (firstTile->image->yuvPlanes[AVIF_CHAN_U] && firstTile->image->yuvPlanes[AVIF_CHAN_V]);
         if ((tile->image->width != firstTile->image->width) || (tile->image->height != firstTile->image->height) ||
             (tile->image->depth != firstTile->image->depth) || (tile->image->yuvFormat != firstTile->image->yuvFormat) ||
-            (tile->image->yuvRange != firstTile->image->yuvRange) || (uvPresent != firstTileUVPresent) ||
-            (tile->image->colorPrimaries != firstTile->image->colorPrimaries) ||
+            (tile->image->yuvRange != firstTile->image->yuvRange) || (tile->image->colorPrimaries != firstTile->image->colorPrimaries) ||
             (tile->image->transferCharacteristics != firstTile->image->transferCharacteristics) ||
             (tile->image->matrixCoefficients != firstTile->image->matrixCoefficients)) {
             avifDiagnosticsPrintf(data->diag, "Grid image contains mismatched tiles");