Slick Daddy e01092aa38 Kernel FS: close guest→host sandbox escapes in the path resolver (#478)
* Kernel FS: default-deny unmapped guest paths (fixes absolute-path host escape)

ResolveGuestPath returned any unrecognized guest path verbatim as the host
path. Because absolute paths ("/etc/passwd", "C:\Windows\...") are already
fully qualified, they skipped the relative-path app0 fallback and were handed
straight to FileStream/File.Delete/etc., giving a malicious game arbitrary
host-file read/write/delete outside the sandbox.

Return string.Empty (deny) on fallthrough instead. Most callers already treat
a nonexistent host path as NOT_FOUND; open/truncate/rename get an explicit
empty-path guard so a denied path can't reach FileStream and throw an
ArgumentException their catch blocks don't cover.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: contain built-in mounts (fixes Windows drive-letter injection)

The built-in mount branches (app0/temp0/download0/hostapp/devlog) combined
the mount-relative guest path onto the host root without re-checking
containment. NormalizeMountRelativePath clamps ./.. but splits only on
separators, so a drive-qualified token like "C:" survives as a segment and
Path.Combine then discards the mount root, yielding a raw host path such as
"C:\Windows\..." (arbitrary host read/write).

Route every built-in branch through a new CombineWithinMount helper that
re-resolves with Path.GetFullPath and verifies the result stays under the
mount root -- the same guard TryResolveRegisteredGuestMount already applied.
Denied paths return string.Empty, which callers treat as unresolved.

AprStreamingContractTests passed a raw Path.GetTempFileName() as the guest
path, relying on the now-removed absolute-path passthrough; updated it to
address the file through a registered mount.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: reject reparse points inside mounts (fixes symlink escape)

Lexical containment (Path.GetFullPath + StartsWith) proves the textual
path stays under the mount root but does not follow symlinks/junctions.
A malicious game dump could plant a reparse point inside app0/temp0/etc.
pointing outside it, so a contained-looking path resolved onto the host
filesystem. Walk each existing component from the mount root to the
candidate and refuse any reparse point, in both the built-in and
registered-mount resolution paths. Mirrors AvPlayer's existing defense.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: fail closed when path containment cannot be verified

The reparse-point and drive-letter containment guards call Path.GetFullPath
and File.GetAttributes on untrusted guest paths. Both throw on crafted
over-long or invalid-char input, and ResolveGuestPath runs outside the file
syscalls' try blocks, so such a path was a guest-triggerable crash rather
than a denial.

Wrap the GetFullPath calls in CombineWithinMount and the registered-mount
path, and widen the GetAttributes catch, to treat any access/format failure
as an escape (deny) instead of propagating. Also tighten the ".." fallback
check so a legitimate file named "..foo" is not falsely rejected, and hoist
the repeated Path.GetFullPath(mountRoot) into a local.

Adds a regression test asserting the resolver returns without throwing for
an over-long and a NUL-embedded path under a mount.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: assert malformed paths resolve to empty, not just no-throw

The fail-closed regression test asserted only Assert.NotNull, which a
non-nullable string return can never violate via its value (only a throw,
which aborts the test earlier anyway). Tighten to Assert.Equal(string.Empty)
so it also locks in fail-CLOSED: a regression where a malformed path resolved
to a non-empty host path would now be caught.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: route new AMPR batch tests through a registered mount

Merging main brought in three AprStreamingContractTests that pass raw
Path.GetTempFileName()/temp host paths as guest paths. The default-deny
resolver from this branch rejects absolute host paths, so MissingMidBatch
failed at index 0 instead of the intended index 1. Address the present
file through a registered mount (as ResolveStatAndReadFile already does)
so entries 0 and 2 resolve and the batch fails at the genuinely-missing
entry. The two all-missing tests were unaffected but share the fix's intent.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Kernel FS: make a matched-mount denial terminal; fix Unix-only test asserts

A registered mount that claims a path by prefix but denies it (failed
containment or a reparse point inside the mount) now short-circuits in
ResolveGuestPath instead of falling through to the built-in mount branches.
The fall-through let an overlapping prefix (a registered "/app0" vs the
built-in SHARPEMU_APP0_DIR branch, which resolves against a cached root)
re-resolve a denied path and turn the denial back into a resolution -- the
reparse-point escape reappeared on Linux CI through exactly this path.

Also fix two tests that asserted Windows-specific behavior unconditionally:
a "C:\..." path is not absolute on Unix (it resolves contained under the
mount there), and that case is now pinned to Windows only.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: slick-daddy <slick-daddy@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-21 00:58:34 +03:00
2026-07-20 14:23:04 +03:00
2026-07-19 01:26:01 +03:00
2026-03-11 15:48:28 +03:00

SharpEmu

An experimental PlayStation 5 emulator for Windows, Linux and macOS.

Join our Discord

Join our Discord for development updates, compatibility discussions, support, and community chat.


Note

SharpEmu supports Windows x64, Linux x64, and macOS x64. Apple Silicon Macs can run the macOS x64 build through Rosetta 2, and Windows on ARM devices (e.g. Snapdragon) can run the Windows x64 build through Windows' built-in x64 emulation.

Warning

SharpEmu is an experimental PS5 emulator developed from scratch in C#. The current focus is on accuracy and infrastructure setup rather than game-specific compatibility.

Info

SharpEmu is an emulator project currently in its early stages of development.

This project is developed purely for research and educational purposes. There are no commercial goals associated with it. We enjoy learning about system architecture and reverse engineering.

SharpEmu focuses exclusively on the PlayStation 5.
Our goal is not to emulate PS4 games, as there is already an excellent emulator dedicated to that platform: ShadPS4.

Games Tested

Demons Souls Remake Dreaming Sarah
Bloodborne screenshot Dreaming Sarah
Void Terrarium Dead Cells
Void Terrarium Dead Cells

Status

The emulator can currently load the eboot.bin of real games, execute native CPU instructions, and partially handle kernel-related functionality. However, several critical components are still missing.

Current capabilities include:

  • Loading eboot.bin and .elf files
  • Executing native CPU instructions
  • Reading basic game metadata (title, version, etc.)
  • Loading system modules (prx / sys_module)
  • Partial support for some kernel functions
  • Fiber and AMPR exports
  • PlayGo scenarios
  • Initial loading game files
  • Shader/resource submits and AGC initial
  • Video outputs in some games

Some games have reached like sceVideoOut and AGC stages.

SharpEmu supports Windows, Linux, and macOS hosts. Video output uses Vulkan on Windows and Linux, and MoltenVK on macOS. Platform support is still experimental, so compatibility and performance vary by game, operating system, and GPU driver.

Using

Download the release archive for your operating system, extract it, and launch SharpEmu with the path to a legally obtained game's eboot.bin.

Windows PowerShell:

.\SharpEmu.exe "C:\path\to\game\eboot.bin" 2>&1 |
  Tee-Object -FilePath "SharpEmu.log"

Linux and macOS:

chmod +x ./SharpEmu

./SharpEmu "/path/to/game/eboot.bin" 2>&1 |
  tee SharpEmu.log

A Vulkan-capable GPU and current graphics driver are required. The macOS release includes the MoltenVK Vulkan implementation.

Important

This project does not support or condone piracy.
All games used during development and testing are dumped from consoles that we personally own.
Users are expected to use legally obtained copies of their games.

Build

  1. Install the .NET SDK version specified in global.json.
  2. Clone the repository: git clone https://github.com/sharpemu/sharpemu.git
  3. Open the solution file (SharpEmu.slnx) in VSCode.
  4. Build the project: dotnet build or dotnet publish
  5. Build artifacts will be located in the artifacts directory.

Disclaimer

SharpEmu is an experimental emulator intended for research and educational purposes.

This project does not contain any copyrighted system firmware, game data, or proprietary PlayStation assets.

Special Thanks

The following projects were extremely helpful during development:

  • ShadPS4
    Helped with understanding the basic architecture of the PlayStation 4.

  • Kyty
    One of the few PS5 emulator projects available and very useful for studying native code execution.

  • Ryujinx
    Provided valuable references for filesystem handling and low-level C# implementation patterns.

License

Contributing

Before opening an issue or pull request, please read our contribution guidelines:

CONTRIBUTING.md

The guide covers:

  • Coding style and formatting
  • AI-assisted contributions
  • Pull request expectations
  • Testing guidelines
  • Legal and reverse engineering policy
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