You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
53 lines
1.4 KiB
53 lines
1.4 KiB
From 1c127eb3cb7653bd61b61f9c3cfeb36fd10edab1 Mon Sep 17 00:00:00 2001
|
|
From: Even Rouault <even.rouault@spatialys.com>
|
|
Date: Sat, 12 May 2018 15:32:31 +0200
|
|
Subject: [PATCH 3/4] LZWDecodeCompat(): fix potential index-out-of-bounds
|
|
write. Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2780 /
|
|
CVE-2018-8905
|
|
|
|
The fix consists in using the similar code LZWDecode() to validate we
|
|
don't write outside of the output buffer.
|
|
---
|
|
libtiff/tif_lzw.c | 18 ++++++++++++------
|
|
1 file changed, 12 insertions(+), 6 deletions(-)
|
|
|
|
diff --git a/libtiff/tif_lzw.c b/libtiff/tif_lzw.c
|
|
index bc8f9c8..186ea3c 100644
|
|
--- a/libtiff/tif_lzw.c
|
|
+++ b/libtiff/tif_lzw.c
|
|
@@ -604,6 +604,7 @@ LZWDecodeCompat(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
|
|
char *tp;
|
|
unsigned char *bp;
|
|
int code, nbits;
|
|
+ int len;
|
|
long nextbits, nextdata, nbitsmask;
|
|
code_t *codep, *free_entp, *maxcodep, *oldcodep;
|
|
|
|
@@ -755,13 +756,18 @@ LZWDecodeCompat(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
|
|
} while (--occ);
|
|
break;
|
|
}
|
|
- assert(occ >= codep->length);
|
|
- op += codep->length;
|
|
- occ -= codep->length;
|
|
- tp = op;
|
|
+ len = codep->length;
|
|
+ tp = op + len;
|
|
do {
|
|
- *--tp = codep->value;
|
|
- } while( (codep = codep->next) != NULL );
|
|
+ int t;
|
|
+ --tp;
|
|
+ t = codep->value;
|
|
+ codep = codep->next;
|
|
+ *tp = (char)t;
|
|
+ } while (codep && tp > op);
|
|
+ assert(occ >= len);
|
|
+ op += len;
|
|
+ occ -= len;
|
|
} else {
|
|
*op++ = (char)code;
|
|
occ--;
|
|
--
|
|
2.17.0
|
|
|