From f3aefc6d071b807ddacae0a0bc49f09c38e18490 Mon Sep 17 00:00:00 2001
From: Stanislav Malyshev <stas@php.net>
Date: Sun, 17 Mar 2019 22:54:46 -0700
Subject: [PATCH] Fix bug #77753 - Heap-buffer-overflow in php_ifd_get32s

---
 ext/exif/exif.c              |   4 ++++
 ext/exif/tests/bug77753.phpt |  16 ++++++++++++++++
 ext/exif/tests/bug77753.tiff | Bin 0 -> 873 bytes
 3 files changed, 20 insertions(+)
 create mode 100644 ext/exif/tests/bug77753.phpt
 create mode 100644 ext/exif/tests/bug77753.tiff

diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index fe89b85..0b5bb5a 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -2802,6 +2802,10 @@ static int exif_process_IFD_in_MAKERNOTE(image_info_type *ImageInfo, char * valu
 		exif_error_docref("exif_read_data#error_ifd" EXIFERR_CC, ImageInfo, E_WARNING, "Illegal IFD size: 2 + 0x%04X*12 = 0x%04X > 0x%04X", NumDirEntries, 2+NumDirEntries*12, value_len);
 		return FALSE;
 	}
+	if ((dir_start - value_ptr) > value_len - (2+NumDirEntries*12)) {
+		exif_error_docref("exif_read_data#error_ifd" EXIFERR_CC, ImageInfo, E_WARNING, "Illegal IFD size: 0x%04X > 0x%04X", (dir_start - value_ptr) + (2+NumDirEntries*12), value_len);
+		return FALSE;
+	}
 
 	for (de=0;de<NumDirEntries;de++) {
 		if (!exif_process_IFD_TAG(ImageInfo, dir_start + 2 + 12 * de,
diff --git a/ext/exif/tests/bug77753.phpt b/ext/exif/tests/bug77753.phpt
new file mode 100644
index 0000000..d987a5c
--- /dev/null
+++ b/ext/exif/tests/bug77753.phpt
@@ -0,0 +1,16 @@
+--TEST--
+Bug #77753 (Heap-buffer-overflow in php_ifd_get32s)
+--SKIPIF--
+<?php if (!extension_loaded('exif')) print 'skip exif extension not available';?>
+--FILE--
+<?php
+var_dump(exif_read_data(__DIR__."/bug77753.tiff"));
+?>
+DONE
+--EXPECTF--
+%A
+Warning: exif_read_data(bug77753.tiff): Illegal IFD size: 0x006A > 0x0065 in %sbug77753.php on line %d
+
+Warning: exif_read_data(bug77753.tiff): Invalid TIFF file in %sbug77753.php on line %d
+bool(false)
+DONE
\ No newline at end of file

-- 
2.1.4