Fix: security scan issues related to memory safety & input validation

[sruthi0107]

Motivation

A security audit of the OpenVX GDF loader and AGO parser flagged several memory-safety and input-validation issues (buffer/integer overflows, a format-string bug, and an unrestricted module load). This PR fixes all of them.

Technical Details

• Bounded string copies (ago_interface.cpp, ago_util.cpp): unbounded strcpy/sscanf("%s") of GDF tokens into fixed stack buffers replaced with snprintf / width specifiers (%63s, %255s) and length-checked memcpys.
  • Heap OOB write (ago_interface.cpp): added an AGO_MAX_PARAMS bounds check before the node->paramList[p] write.
  • Integer overflows (ago_util.cpp): tensor/image/remap allocation sizes now computed in 64-bit with __builtin_mul_overflow guards.
  • Format string (vxImage.cpp): GDF filename templates are validated (integer conversions only) before use as an snprintf format, blocking %n/%s.
  • Unrestricted import (ago_interface.cpp): agoLoadModule rejects module names with path separators or .., so a GDF can't dlopen an arbitrary library by path (bare search-path names still load).

Test Plan

Build from source and run ctests

Test Result

All ctests pass