Check return value before dereferencing
Check return value before dereferencing

Thanks oss-fuzz
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=45390

dengert/OpenSC,OpenSC/OpenSC,mouse07410/OpenSC,metsma/OpenSC,mouse07410/OpenSC,dengert/OpenSC,fabled/OpenSC,philipWendland/OpenSC,OpenSC/OpenSC,LudovicRousseau/OpenSC,metsma/OpenSC,fabled/OpenSC,LudovicRousseau/OpenSC,philipWendland/OpenSC,mouse07410/OpenSC,fabled/OpenSC,OpenSC/OpenSC,dengert/OpenSC,LudovicRousseau/OpenSC,philipWendland/OpenSC,metsma/OpenSC,fabled/OpenSC