Attack Surface Analysis for gfx-rs/gfx

Attack Surface: Shader Compilation Vulnerabilities

Description: Bugs or weaknesses in the shader compiler (e.g., shaderc, driver compilers) that can be triggered by maliciously crafted shaders during compilation.
gfx Contribution: gfx-rs relies on shader compilation to convert shader code into GPU-executable code, using external tools or driver-provided compilers, thus inheriting their potential vulnerabilities.
Example: A specially crafted GLSL shader submitted to gfx-rs for compilation triggers a buffer overflow in shaderc, leading to code execution on the host system during the compilation process.
Impact: Code execution on the host system, denial of service (compiler crash), information disclosure (if compiler leaks internal data).
Risk Severity: High to Critical
Mitigation Strategies:
- Use up-to-date shader toolchains (ensure shaderc and graphics drivers are updated).
- Implement pre-compilation shader validation steps (e.g., using linters or static analysis tools).
- Consider sandboxing the shader compilation process.
- Restrict shader sources to trusted origins and avoid dynamic shader generation from untrusted input.

Attack Surface: Shader Out-of-Bounds Memory Access

Description: Shaders attempting to read or write memory outside of allocated buffers or textures during GPU execution.
gfx Contribution: gfx-rs provides APIs for creating and managing buffers and textures that shaders operate on. Incorrect shader logic or vulnerabilities in shaders can lead to out-of-bounds access when using these resources managed by gfx-rs.
Example: A fragment shader in a gfx-rs application, due to flawed logic, reads texture data beyond the allocated texture size, potentially leaking data from other parts of GPU memory or causing a crash.
Impact: Data corruption, information disclosure (reading sensitive data from GPU memory), denial of service (GPU crash or application crash).
Risk Severity: Medium to High
Mitigation Strategies:
- Thoroughly review and test shader code for out-of-bounds access issues.
- Use shader debuggers and validation layers during development.
- Implement bounds checking within shaders, especially for user-controlled inputs.
- Validate resource sizes to prevent shaders from accessing beyond allocated regions due to incorrect setup.
- Utilize address sanitizers (if available) during shader development and testing.

Attack Surface: Use-After-Free/Double-Free of Graphics Resources

Description: Bugs in the application's resource management logic leading to using graphics resources (buffers, textures, pipelines) after they have been freed or attempting to free them multiple times.
gfx Contribution: gfx-rs relies on the application to correctly manage the lifetime of graphics resources created through its API. Incorrect resource management when using gfx-rs APIs can lead to these memory safety issues.
Example: An application incorrectly frees a buffer created via gfx-rs that is still being used by a command buffer. When the command buffer is executed, it attempts to access the freed buffer, leading to a crash or potentially exploitable memory corruption.
Impact: Application crash, memory corruption, potential for code execution (in more complex scenarios).
Risk Severity: Medium to High
Mitigation Strategies:
- Utilize RAII (Resource Acquisition Is Initialization) principles and smart pointers for gfx-rs resources.
- Implement clear ownership and lifetime tracking for gfx-rs resources.
- Thoroughly review and test resource management code, especially around gfx-rs resource handling.
- Use memory debugging tools and graphics API validation layers during development.