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From b18012dae552f85dcc5c57d3bf4e997a15b1cc1c Mon Sep 17 00:00:00 2001
From: erouault <erouault>
Date: Sun, 27 Dec 2015 16:55:20 +0000
Subject: [PATCH] * libtiff/tif_next.c: fix potential out-of-bound write in
NeXTDecode() triggered by http://lcamtuf.coredump.cx/afl/vulns/libtiff5.tif
(bugzilla #2508)
---
ChangeLog | 6 ++++++
libtiff/tif_next.c | 10 ++++++++--
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/libtiff/tif_next.c b/libtiff/tif_next.c
index dd669cc..0a5b635 100644
--- a/libtiff/tif_next.c
+++ b/libtiff/tif_next.c
@@ -37,7 +37,7 @@
case 0: op[0] = (unsigned char) ((v) << 6); break; \
case 1: op[0] |= (v) << 4; break; \
case 2: op[0] |= (v) << 2; break; \
- case 3: *op++ |= (v); break; \
+ case 3: *op++ |= (v); op_offset++; break; \
} \
}
@@ -106,6 +106,7 @@ NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
uint32 imagewidth = tif->tif_dir.td_imagewidth;
if( isTiled(tif) )
imagewidth = tif->tif_dir.td_tilewidth;
+ tmsize_t op_offset = 0;
/*
* The scanline is composed of a sequence of constant
@@ -122,10 +123,15 @@ NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
* bounds, potentially resulting in a security
* issue.
*/
- while (n-- > 0 && npixels < imagewidth)
+ while (n-- > 0 && npixels < imagewidth && op_offset < scanline)
SETPIXEL(op, grey);
if (npixels >= imagewidth)
break;
+ if (op_offset >= scanline ) {
+ TIFFErrorExt(tif->tif_clientdata, module, "Invalid data for scanline %ld",
+ (long) tif->tif_row);
+ return (0);
+ }
if (cc == 0)
goto bad;
n = *bp++, cc--;
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