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Patch bug68735.patch for *Directory/Filesystem functions Bug #68735

Patch version 2015-01-03 18:17 UTC

Return to Bug #68735 | Download this patch
Patch Revisions:

Developer: ab@php.net

diff --git a/ext/fileinfo/libmagic/softmagic.c b/ext/fileinfo/libmagic/softmagic.c
index 7e0c856..e7b7855 100644
--- a/ext/fileinfo/libmagic/softmagic.c
+++ b/ext/fileinfo/libmagic/softmagic.c
@@ -884,14 +884,17 @@ mconvert(struct magic_set *ms, struct magic *m, int flip)
 		size_t sz = file_pstring_length_size(m);
 		char *ptr1 = p->s, *ptr2 = ptr1 + sz;
 		size_t len = file_pstring_get_length(m, ptr1);
-		if (len >= sizeof(p->s)) {
+		sz = sizeof(p->s) - sz; /* maximum length of string */
+		if (len >= sz) {
 			/*
 			 * The size of the pascal string length (sz)
 			 * is 1, 2, or 4. We need at least 1 byte for NUL
 			 * termination, but we've already truncated the
 			 * string by p->s, so we need to deduct sz.
+			 * Because we can use one of the bytes of the length
+			 * after we shifted as NUL termination.
 			 */ 
-			len = sizeof(p->s) - sz;
+			len = sz;
 		}
 		while (len--)
 			*ptr1++ = *ptr2++;
--- /dev/null	Sat Jan  3 19:01:50 2015
+++ a/ext/fileinfo/tests/bug68735.phpt	Sat Jan  3 18:57:32 2015
@@ -0,0 +1,16 @@
+--TEST--
+Bug #68735 fileinfo out-of-bounds memory access
+--SKIPIF--
+<?php require_once(dirname(__FILE__) . '/skipif.inc'); ?>
+--FILE--
+<?php
+	$test_file = dirname(__FILE__) . DIRECTORY_SEPARATOR . "bug68735.jpg";
+	$f = new finfo;
+
+	var_dump($f->file($test_file));
+
+?>
+===DONE===
+--EXPECTF--
+string(%d) "JPEG image data, JFIF standard 1.01, comment: "%S""
+===DONE===
 
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