Floating-point exception (SIGFPE) in COLLADASaxFWL::MeshLoader::initializeTexCoordsOffset() at COLLADASaxFWLMeshLoader.cpp:951

A crafted input leads to crash (divide-by-zero vulnerability) at `COLLADASaxFWLMeshLoader.cpp:951` in opencolladavalidator `v1.6.68` (the latest version, checked on Ubuntu/Debian packages and current master).

PoC: [PoC.zip](https://github.com/KhronosGroup/OpenCOLLADA/files/6176071/PoC.zip)

Triggered by:

`./OpenCOLLADAValidator PoC.dae`

ASAN report:

```
$ ./OpenCOLLADAValidator PoC.dae
AddressSanitizer:DEADLYSIGNAL
=================================================================
==1655395==ERROR: AddressSanitizer: FPE on unknown address 0x55899c054fd6 (pc 0x55899c054fd6 bp 0x000000000002 sp 0x7fffcabc85c0 T0)
#0 0x55899c054fd5 in COLLADASaxFWL::MeshLoader::initializeTexCoordsOffset() /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLMeshLoader.cpp:953
#1 0x55899c056e07 in COLLADASaxFWL::MeshLoader::initializeOffsets() /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLMeshLoader.cpp:734
#2 0x55899c0571b1 in COLLADASaxFWL::MeshLoader::begin__p() /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLMeshLoader.cpp:1464
#3 0x55899b231812 in GeneratedSaxParser::ParserTemplate::elementBegin(char const*, GeneratedSaxParser::ParserAttributes const&) /home/nale/OpenCOLLADA-1.6.63/GeneratedSaxParser/include/GeneratedSaxParserParserTemplate.h:2059
#4 0x55899c09a3e0 in GeneratedSaxParser::LibxmlSaxParser::startElement(void*, unsigned char const*, unsigned char const**) /home/nale/OpenCOLLADA-1.6.63/GeneratedSaxParser/src/GeneratedSaxParserLibxmlSaxParser.cpp:179
#5 0x7fed0d2285a6 in xmlParseStartTag (/lib/x86_64-linux-gnu/libxml2.so.2+0x4b5a6)
#6 0x7fed0d22af27 (/lib/x86_64-linux-gnu/libxml2.so.2+0x4df27)
#7 0x7fed0d2307cf in xmlParseContent (/lib/x86_64-linux-gnu/libxml2.so.2+0x537cf)
#8 0x7fed0d231f0f in xmlParseDocument (/lib/x86_64-linux-gnu/libxml2.so.2+0x54f0f)
#9 0x55899c09a9cf in GeneratedSaxParser::LibxmlSaxParser::parseFile(char const*) /home/nale/OpenCOLLADA-1.6.63/GeneratedSaxParser/src/GeneratedSaxParserLibxmlSaxParser.cpp:103
#10 0x55899ac8a3ca in COLLADASaxFWL::VersionParser::createAndLaunchParser() /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLVersionParser.cpp:329
#11 0x55899ac87a3e in COLLADASaxFWL::FileLoader::load() /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLFileLoader.cpp:79
#12 0x55899ac182be in COLLADASaxFWL::Loader::loadDocument(std::__cxx11::basic_string, std::allocator > const&, COLLADAFW::IWriter*) /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLLoader.cpp:226
#13 0x55899ac086f4 in parse(char*, ValidationErrorHandler&) /home/nale/OpenCOLLADA-1.6.63/COLLADAValidator/src/main.cpp:37
#14 0x55899abb4fbc in main /home/nale/OpenCOLLADA-1.6.63/COLLADAValidator/src/main.cpp:54
#15 0x7fed0ccc50b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
#16 0x55899ac078ad in _start (/home/nale/OpenCOLLADA-1.6.63/build/bin/OpenCOLLADAValidator+0x75a8ad)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: FPE /home/nale/OpenCOLLADA-1.6.63/COLLADASaxFrameworkLoader/src/COLLADASaxFWLMeshLoader.cpp:953 in COLLADASaxFWL::MeshLoader::initializeTexCoordsOffset()
==1655395==ABORTING
```

GDB info:



stride variable is zero and program received SIGFPE as follows.

Environment:
Host Operating System and version: Ubuntu 20.04.2 LTS
Host CPU architecture: x86_64

Start in COLLADASaxFrameworkLoader/src/COLLADASaxFWLMeshLoader.cpp at MeshLoader::initializeTexCoordsOffset(), especially around line 951, then trace initializeOffsets() as needed. Run OpenCOLLADAValidator with the provided PoC.dae and verify that the crafted input no longer causes the reported SIGFPE when stride is zero.

Written by the indexing model from the issue text.