From b18012dae552f85dcc5c57d3bf4e997a15b1cc1c Mon Sep 17 00:00:00 2001 From: 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--;