Upstream test patch dropped (binary patch not supported)


From ede59c8feb4b80e1b94e4abdaa0711051e2912ab Mon Sep 17 00:00:00 2001
From: Anatol Belski <ab@php.net>
Date: Sun, 4 Jan 2015 14:20:21 +0100
Subject: [PATCH] Fixed bug #68735 fileinfo out-of-bounds memory access

---
 NEWS                              |   7 +++++++
 ext/fileinfo/libmagic/softmagic.c |   7 +++++--
 ext/fileinfo/tests/bug68735.jpg   | Bin 0 -> 24 bytes
 ext/fileinfo/tests/bug68735.phpt  |  16 ++++++++++++++++
 4 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 ext/fileinfo/tests/bug68735.jpg
 create mode 100644 ext/fileinfo/tests/bug68735.phpt

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++;