From 07b761b0862bcea65b83052b9d960c4459af0466 Mon Sep 17 00:00:00 2001
From: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Date: Sun, 18 Sep 2016 16:25:22 -0700
Subject: [PATCH 2/2] mkfontscale: Avoid a buffer underrun
https://bugs.freedesktop.org/show_bug.cgi?id=96905
=================================================================
==3068==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000de6f at pc 0x000109df79d1 bp 0x7fff55e37d90 sp 0x7fff55e37550
READ of size 1 at 0x60300000de6f thread T0
#0 0x109df79d0 in wrap_strcmp (libclang_rt.asan_osx_dynamic.dylib+0xe9d0)
#1 0x109dc8ef7 in fontFileOpen (mkfontscale+0x100001ef7)
#2 0x109dc8e0b in bitmapIdentify (mkfontscale+0x100001e0b)
#3 0x109dcc874 in doDirectory (mkfontscale+0x100005874)
#4 0x109dcbc78 in main (mkfontscale+0x100004c78)
#5 0x7fff9083f5ac in start (libdyld.dylib+0x35ac)
#6 0x3 (<unknown module>)
0x60300000de6f is located 1 bytes to the left of 20-byte region [0x60300000de70,0x60300000de84)
allocated by thread T0 here:
#0 0x109e34570 in wrap_malloc (libclang_rt.asan_osx_dynamic.dylib+0x4b570)
#1 0x109dca92a in dsprintf (mkfontscale+0x10000392a)
#2 0x109dcc788 in doDirectory (mkfontscale+0x100005788)
#3 0x109dcbc78 in main (mkfontscale+0x100004c78)
#4 0x7fff9083f5ac in start (libdyld.dylib+0x35ac)
#5 0x3 (<unknown module>)
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
---
ident.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ident.c b/ident.c
index 22d3648..f7fe9e1 100644
--- a/ident.c
+++ b/ident.c
@@ -83,7 +83,7 @@ static inline void *
fontFileOpen(fontFile *ff, const char *filename) {
int n = strlen(filename);
- if (strcmp(filename + n - 4, ".bz2") == 0) {
+ if (n > 4 && strcmp(filename + n - 4, ".bz2") == 0) {
ff->type = bz2FontFile;
ff->f.bz2 = BZ2_bzopen(filename, "rb");
ff->pos = 0;
--
2.10.0 (Apple Git-77)