Fix bug #78222 (heap-buffer-overflow on exif_scan_thumbnail)

smalyshev · smalyshev · commit dea2989ab8ba · 2019-07-29T00:53:28.000-07:00
diff --git a/ext/exif/exif.c b/ext/exif/exif.c
@@ -3498,7 +3498,7 @@ static int exif_scan_thumbnail(image_info_type *ImageInfo)
 	size_t          length=2, pos=0;
 	jpeg_sof_info   sof_info;
 
-	if (!data) {
+	if (!data || ImageInfo->Thumbnail.size < 4) {
 		return FALSE; /* nothing to do here */
 	}
 	if (memcmp(data, "\xFF\xD8\xFF", 3)) {
diff --git a/ext/exif/tests/bug78222.jpg b/ext/exif/tests/bug78222.jpg
diff --git a/ext/exif/tests/bug78222.phpt b/ext/exif/tests/bug78222.phpt
@@ -0,0 +1,11 @@
+--TEST--
+Bug #78222 (heap-buffer-overflow on exif_scan_thumbnail)
+--SKIPIF--
+<?php if (!extension_loaded('exif')) print 'skip exif extension not available';?>
+--FILE--
+<?php
+exif_read_data(__DIR__."/bug78222.jpg", 'THUMBNAIL', FALSE, TRUE);
+?>
+DONE
+--EXPECTF--
+DONE

Original file line number	Diff line number	Diff line change
`@@ -3498,7 +3498,7 @@ static int exif_scan_thumbnail(image_info_type *ImageInfo)`
`3498`	`3498`	`size_t length=2, pos=0;`
`3499`	`3499`	`jpeg_sof_info sof_info;`
`3500`	`3500`
`3501`		`- if (!data) {`
	`3501`	`+ if (!data \|\| ImageInfo->Thumbnail.size < 4) {`
`3502`	`3502`	`return FALSE; /* nothing to do here */`
`3503`	`3503`	`}`
`3504`	`3504`	`if (memcmp(data, "\xFF\xD8\xFF", 3)) {`