Patch for 72618

72618.diff

commit 41131cd41d2fd2e0c2f332a27988df75659c42e4
Author: Stanislav Malyshev <stas@php.net>
Date:   Mon Jul 18 23:21:51 2016 -0700

    Fix bug #72618: NULL Pointer Dereference in exif_process_user_comment

diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index 760e746..74b652b 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -2623,6 +2623,7 @@ static int exif_process_user_comment(image_info_type *ImageInfo, char **pszInfoP
 	*pszEncoding = NULL;
 	/* Copy the comment */
 	if (ByteCount>=8) {
+		const zend_encoding *from, *to;
 		if (!memcmp(szValuePtr, "UNICODE\0", 8)) {
 			*pszEncoding = estrdup((const char*)szValuePtr);
 			szValuePtr = szValuePtr+8;
@@ -2643,14 +2644,16 @@ static int exif_process_user_comment(image_info_type *ImageInfo, char **pszInfoP
 			} else {
 				decode = ImageInfo->decode_unicode_le;
 			}
+			to = zend_multibyte_fetch_encoding(ImageInfo->encode_unicode TSRMLS_CC);
+			from = zend_multibyte_fetch_encoding(decode TSRMLS_CC);
 			/* XXX this will fail again if encoding_converter returns on error something different than SIZE_MAX   */
-			if (zend_multibyte_encoding_converter(
+			if (!to || !from || zend_multibyte_encoding_converter(
 					(unsigned char**)pszInfoPtr,
 					&len,
 					(unsigned char*)szValuePtr,
 					ByteCount,
-					zend_multibyte_fetch_encoding(ImageInfo->encode_unicode TSRMLS_CC),
-					zend_multibyte_fetch_encoding(decode TSRMLS_CC)
+					to,
+					from
 					TSRMLS_CC) == (size_t)-1) {
 				len = exif_process_string_raw(pszInfoPtr, szValuePtr, ByteCount);
 			}
@@ -2665,13 +2668,15 @@ static int exif_process_user_comment(image_info_type *ImageInfo, char **pszInfoP
 			szValuePtr = szValuePtr+8;
 			ByteCount -= 8;
 			/* XXX this will fail again if encoding_converter returns on error something different than SIZE_MAX   */
-			if (zend_multibyte_encoding_converter(
+			to = zend_multibyte_fetch_encoding(ImageInfo->encode_jis TSRMLS_CC);
+			from = zend_multibyte_fetch_encoding(ImageInfo->motorola_intel ? ImageInfo->decode_jis_be : ImageInfo->decode_jis_le TSRMLS_CC);
+			if (!to || !from || zend_multibyte_encoding_converter(
 					(unsigned char**)pszInfoPtr,
 					&len,
 					(unsigned char*)szValuePtr,
 					ByteCount,
-					zend_multibyte_fetch_encoding(ImageInfo->encode_jis TSRMLS_CC),
-					zend_multibyte_fetch_encoding(ImageInfo->motorola_intel ? ImageInfo->decode_jis_be : ImageInfo->decode_jis_le TSRMLS_CC)
+					to,
+					from
 					TSRMLS_CC) == (size_t)-1) {
 				len = exif_process_string_raw(pszInfoPtr, szValuePtr, ByteCount);
 			}
diff --git a/ext/exif/tests/bug72618.jpg b/ext/exif/tests/bug72618.jpg
new file mode 100644
index 0000000..0a61ae2
Binary files /dev/null and b/ext/exif/tests/bug72618.jpg differ
diff --git a/ext/exif/tests/bug72618.phpt b/ext/exif/tests/bug72618.phpt
new file mode 100644
index 0000000..424c0ec
--- /dev/null
+++ b/ext/exif/tests/bug72618.phpt
@@ -0,0 +1,11 @@
+--TEST--
+Bug 72618 (NULL Pointer Dereference in exif_process_user_comment)
+--SKIPIF--
+<?php if (!extension_loaded('exif')) print 'skip exif extension not available';?>
+--FILE--
+<?php
+var_dump(count(exif_read_data(dirname(__FILE__) . "/bug72618.jpg")));
+?>
+--EXPECTF--
+Warning: exif_read_data(bug72618.jpg): IFD data bad offset: 0x058E length 0x0030 in %s/bug72618.php on line %d
+int(13)
\ No newline at end of file