A crafted .cso compressed ISO could trigger a heap buffer overflow on any
sector read, reachable via ordinary gameplay.
Two root causes:
1. Unvalidated frame index deltas. ReadBlock/ReadBlocks computed a
compressed read range from two adjacent frame-index-table entries.
With non-monotonic entries, compressedReadEnd - compressedReadPos
underflows as u64, producing a huge read size that fileLoader->ReadAt()
wrote into the fixed-size readBuffer.
2. hdr.align (indexShift, 0-255) used as '1 << indexShift' was undefined
behavior at >= 32, and frameSize + (1 << indexShift) could wrap,
undersizing the buffer while inflate() was configured with the full
frameSize.
Fixes:
- Validate the index table is monotonically non-decreasing in the
constructor.
- Reject files with indexShift > 20.
- Use unsigned shift for buffer size math and store readBufferSize.
- Clamp compressed read sizes to readBufferSize in both ReadBlock and
ReadBlocks.
Some preserved PSP prototype builds were distributed as DVD-R images that contain the actual UMD data inside USER_L0.IMG and, for dual-layer titles, USER_L1.IMG. These images previously required manual extraction, renaming, or concatenation before PPSSPP could load them.
Add support for recognizing these DVD-R wrapper layouts and exposing the embedded UMD image through the normal disc loading path. This includes both ISO-based wrappers and UDF-based wrappers, so preserved prototype dumps can be opened directly without conversion.
This makes PPSSPP compatible with a wider range of preserved developer disc images without relying on title-specific handling.
The primary importance of this patch is to encourage preserving 1:1, perfect disc image dumps in the manner of Redump.org.
This patch has been successfully tested on the following DVD-R ISOs:
https://hiddenpalace.org/Rock_Band_Unplugged_(Dec_10,_2008_prototype)https://hiddenpalace.org/WipEout_Pulse_(May_4,_2007_prototype)https://hiddenpalace.org/Lara_Croft_Tomb_Raider:_Anniversary_(May_19,_2007_prototype)https://hiddenpalace.org/Heatseeker_(Jan_15,_2007_prototype)Fixes#15547.
For CSO versions >= 2, respect the header size field and uncompressed
frame size behavior. This will allow more options for future files, like
adding a field for the CRC or otherwise.
This way we don't get slow startup. This will also cache the CSO data,
for example, rather than the raw data, using up less RAM. It might even
be reasonable to enable on 32-bit.
Henrik Rydgård