Fix bug #60150 (Integer overflow during the parsing of invalid exif header)

ext/exif/exif.c

@@ -2850,11 +2850,11 @@ static int exif_process_IFD_TAG(image_info_type *ImageInfo, char *dir_entry, cha
 		offset_val = php_ifd_get32u(dir_entry+8, ImageInfo->motorola_intel);
 		/* If its bigger than 4 bytes, the dir entry contains an offset. */
 		value_ptr = offset_base+offset_val;
-		if (offset_val+byte_count > IFDlength || value_ptr < dir_entry) {
+		if (byte_count > IFDlength || offset_val > IFDlength-byte_count || value_ptr < dir_entry) {
 			/* It is important to check for IMAGE_FILETYPE_TIFF
 			 * JPEG does not use absolute pointers instead its pointers are
 			 * relative to the start of the TIFF header in APP1 section. */
-			if (offset_val+byte_count>ImageInfo->FileSize || (ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_II && ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_MM && ImageInfo->FileType!=IMAGE_FILETYPE_JPEG)) {
+			if (byte_count > ImageInfo->FileSize || offset_val>ImageInfo->FileSize-byte_count || (ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_II && ImageInfo->FileType!=IMAGE_FILETYPE_TIFF_MM && ImageInfo->FileType!=IMAGE_FILETYPE_JPEG)) {
 				if (value_ptr < dir_entry) {
 					/* we can read this if offset_val > 0 */
 					/* some files have their values in other parts of the file */

ext/exif/tests/bug60150.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Bug #34704 (Integer overflow during the parsing of invalid exif header)
+--SKIPIF--
+<?php if (!extension_loaded('exif')) print 'skip exif extension not available';?>
+--INI--
+output_handler=
+zlib.output_compression=0 
+--FILE--
+<?php
+$infile = dirname(__FILE__).'/bug60150.jpg';
+var_dump(exif_read_data($infile));
+?>
+===DONE===
+--EXPECTF--
+Warning: exif_read_data(bug60150.jpg): Process tag(x9003=DateTimeOri): Illegal pointer offset(x%x + x%x = x%x > x%x) in %s on line %d
+
+Warning: exif_read_data(bug60150.jpg): Error reading from file: got=x%x(=%d) != itemlen-%d=x%x(=%d) in %s on line %d
+
+Warning: exif_read_data(bug60150.jpg): Invalid JPEG file in %s on line %d
+bool(false)
+===DONE===