This commit addresses a critical security vulnerability (OOB write) and
several stability issues in the Radiance HDR parser.
Primary Fix:
* Fixed a heap buffer overflow in the RLE decoding loop (Issue #9748).
The decoder previously failed to verify if a run-length chunk exceeded
the remaining space in the scanline buffer. Added strict bounds checking
(`num_bytes + run_length > width`) before executing `memset` or
`mStream.read` to prevent arbitrary memory corruption.
Additional Security & Stability Improvements:
* Prevented an infinite loop (DoS) in header parsing. Replaced the
`do { ... } while(true);` loop with proper stream state checking
(`while (mStream.getline(...))`) to handle unexpected EOFs gracefully.
* Mitigated integer overflow and Out-Of-Memory (OOM) vulnerabilities by
enforcing maximum sane dimensions (`MAX_IMAGE_DIMENSION` and
`MAX_IMAGE_PIXELS`). This prevents catastrophic memory allocations
triggered by maliciously crafted width/height values.
* Initialized local variables and buffers (`buf`, `gamma`, `exposure`) to
prevent undefined behavior and parsing of stack garbage upon stream read
failures.
Fixes#9748
fd9bcaa735