Vulnerability Advisory : libgphoto2 has OOB read in ptp_unpack_Sony_DPD() enumeration count parsing in ptp-pack.c with LOW Attack Complexity

libgphoto2 is a camera access and control library. Versions up to and including 2.5.33 have an out-of-bounds read in the PTP_DPFF_Enumeration case of `ptp_unpack_Sony_DPD()` in `camlibs/ptp2/ptp-pack.c` (line 856). The function reads a 2-byte enumeration count N via `dtoh16o(data, *poffset)` without verifying that 2 bytes remain in the buffer. The standard `ptp_unpack_DPD()` at line 704 has this exact check, confirming the Sony variant omitted it by oversight. Commit 3b9f9696be76ae51dca983d9dd8ce586a2561845 fixes the issue.