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