Details
=======

Product: libtiff
Affected Versions: <= 4.0.6
Vulnerability Type:  Out-of-bounds Read
Vendor URL: http://www.remotesensing.org/libtiff/
CVE ID: CVE-2016-3625
Credit: Mei Wang of the Cloud Security Team, Qihoo 360

Introduction
============

Out-of-bounds Read occurred in tif_read.c:545 or tif_read.c:402 or tif_read.c:560 in tiff2bw allows attackers to cause a denial of service via a crafted TIFF image.



gdb tiff2bw

(gdb)r sample/tiff2bw_1.tif 1.tif

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7bb4b3a in TIFFFillStrip (tif=0x604010, strip=0) at tif_read.c:545
545                                 td->td_stripoffset[strip] > (uint64)tif->tif_size - bytecount) {
Missing separate debuginfos, use: debuginfo-install glibc-2.17-78.el7.x86_64
(gdb) p td->td_stripoffset[strip]
Cannot access memory at address 0x0
(gdb) bt
#0  0x00007ffff7bb4b3a in TIFFFillStrip (tif=0x604010, strip=0) at tif_read.c:545
#1  0x00007ffff7bb411a in TIFFSeek (tif=0x604010, row=0, sample=0) at tif_read.c:228
#2  0x00007ffff7bb42f2 in TIFFReadScanline (tif=0x604010, buf=0x6076d0, row=0, sample=0) at tif_read.c:295
#3  0x000000000040197e in main (argc=3, argv=0x7fffffffe428) at tiff2bw.c:253
(gdb)


(gdb) r sample/tiff2bw_2.tif 1.tif

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7bb46e4 in TIFFReadRawStrip1 (tif=0x604010, strip=0, buf=0x605620, size=10, module=0x7ffff7bcfa81 <module.3917> "TIFFFillStrip") at tif_read.c:402
402                     ma=(tmsize_t)td->td_stripoffset[strip];
(gdb) p td->td_stripoffset[strip]
Cannot access memory at address 0x0
(gdb) bt
#0  0x00007ffff7bb46e4 in TIFFReadRawStrip1 (tif=0x604010, strip=0, buf=0x605620, size=10, module=0x7ffff7bcfa81 <module.3917> "TIFFFillStrip") at tif_read.c:402
#1  0x00007ffff7bb4d73 in TIFFFillStrip (tif=0x604010, strip=0) at tif_read.c:612
#2  0x00007ffff7bb411a in TIFFSeek (tif=0x604010, row=0, sample=0) at tif_read.c:228
#3  0x00007ffff7bb42f2 in TIFFReadScanline (tif=0x604010, buf=0x6076e0, row=0, sample=0) at tif_read.c:295
#4  0x000000000040197e in main (argc=3, argv=0x7fffffffe428) at tiff2bw.c:253

(gdb) r sample/tiff2bw_3.tif 1.tif

Program received signal SIGSEGV, Segmentation fault.
TIFFFillStrip (tif=0x604010, strip=0) at tif_read.c:560
560                                     TIFFErrorExt(tif->tif_clientdata, module,
(gdb) l
555                                             "got %I64u bytes, expected %I64u",
556                                             (unsigned long) strip,
557                                             (unsigned __int64) tif->tif_size - td->td_stripoffset[strip],
558                                             (unsigned __int64) bytecount);
559     #else
560                                     TIFFErrorExt(tif->tif_clientdata, module,
561
562                                             "Read error on strip %lu; "
563                                             "got %llu bytes, expected %llu",
564                                             (unsigned long) strip,
(gdb) p td->td_stripoffset[strip]
Cannot access memory at address 0x0
(gdb) bt
#0  TIFFFillStrip (tif=0x604010, strip=0) at tif_read.c:560
#1  0x00007ffff7bb411a in TIFFSeek (tif=0x604010, row=0, sample=0) at tif_read.c:228
#2  0x00007ffff7bb42f2 in TIFFReadScanline (tif=0x604010, buf=0x607600, row=0, sample=0) at tif_read.c:295
#3  0x000000000040197e in main (argc=3, argv=0x7fffffffe428) at tiff2bw.c:253

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-3625
http://seclists.org/oss-sec/2016/q2/29