CVE-2017-11338: infinite loop in the Exiv2::Image::printIFDStructure function of image.cpp

[rhertzog]

I'm forwarding a security vulnerability reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=1470913

The file used to reproduce the issue is here:
https://bugzilla.redhat.com/attachment.cgi?id=1298062
(it's a rar archive containing the file used to reproduce the issue)

Here's a copy of the report:

$./exiv2 POC4
RW2 IMAGE

GDB debugging information is as follows:
(gdb) set args POC4
(gdb) r
 ...
(gdb) bt
#0  Exiv2::Image::printIFDStructure (this=<optimized out>, io=..., out=..., option=Exiv2::kpsRecursive, start=0, 
    bSwap=<optimized out>, c=<optimized out>, depth=0) at image.cpp:492
#1  0x00007ffff70b90e1 in Exiv2::Image::printTiffStructure (this=0x611000009dc0, io=..., out=..., 
    option=Exiv2::kpsRecursive, depth=-1, offset=<optimized out>) at image.cpp:518
#2  0x00007ffff724924c in Exiv2::Rw2Image::printStructure (this=<optimized out>, out=..., option=<optimized out>, 
    depth=<optimized out>) at rw2image.cpp:115
#3  0x00007ffff724a1dc in Exiv2::Rw2Image::readMetadata (this=<optimized out>) at rw2image.cpp:134
#4  0x0000000000518d8c in Action::Print::printSummary (this=<optimized out>) at actions.cpp:289
#5  0x0000000000518489 in Action::Print::run (this=0x60400000da50, path=...) at actions.cpp:244
#6  0x00000000004e2ebc in main (argc=<optimized out>, argv=<optimized out>) at exiv2.cpp:170

This vulnerability was triggered in Exiv2::Image::printIFDStructure () at image.cpp:492,which will result in a infinite loop.

 348         do {
 349             // Read top of directory
 350             io.seek(start,BasicIo::beg);
 351             io.read(dir.pData_, 2);
 352             uint16_t   dirLength = byteSwap2(dir,0,bSwap);
 353 
 354             bool tooBig = dirLength > 500;
 355             if ( tooBig ) throw Error(55);
 356 
 357             if ( bFirst && bPrint ) {
 359                 if ( tooBig ) out << Internal::indent(depth) << "dirLength = " << dirLength << std::endl;
 360             }
 361 
 ...
 491             if ( start ) {
 492                 io.read(dir.pData_, 4);
 493                 start = tooBig ? 0 : byteSwap4(dir,0,bSwap);
 494             }
 495         } while (start) ;

This vulnerability is detected by team OWL337, with our custom fuzzer collAFL. Please contact ganshuitao@gmail.com and chaoz@tsinghua.edu.cn if you need more info about the team, the tool or the vulnerability.

[D4N]

This should have been fixed by #79.

[D4N]

The patch is now in 0.26