0xiviel/poc-pytorch-recordoffset

PoC: getRecordOffset() Integer Overflow via Local Header Manipulation

Vulnerability: inline_container.cc:634-637 — getRecordOffset() reads filename_len and extra_len from the ZIP local file header without cross-validating against the central directory. A crafted .pt file with modified local header fields causes the function to return a wrong offset, leading to OOB access, silent data corruption, or DoS via torch.load(mmap=True). On 32-bit platforms, mz_uint64 → size_t truncation silently wraps the offset.

Files

• poc_record_offset_overflow.py — Full PoC (wrong offset demo, mmap impact, within-file corruption, overflow analysis)

Quick Start

pip install torch
python poc_record_offset_overflow.py

Expected Output

• Part 1: get_record_offset() returns 66175 for a 1563-byte file (past EOF by 64612 bytes)
• Part 2: torch.load(mmap=True) fails with RuntimeError (DoS)
• Part 3: Within-file offset reads version record as tensor data → garbage values
• Part 4: 32-bit truncation and 64-bit overflow analysis
• Part 5: Vulnerable code and suggested fix