Unsound usages of unsafe implementation about c_void

[llooFlashooll]

Hi, I am scanning this crate in the latest version using my own static analyzer tool.

Unsafe pointer conversion is found at: src/frameworks/opencl/api/memory.rs:21

pub fn create_buffer(
    context: &Context,
    flags: MemoryFlags,
    size: usize,
    host_pointer: Option<*mut u8>,
) -> Result<Memory, Error> {
    let host_ptr = host_pointer.unwrap_or(ptr::null_mut());
    Ok(Memory::from_c(try!(unsafe {
        API::ffi_create_buffer(
            context.id() as *mut libc::c_void,
            flags.bits(),
            size,
            host_ptr as *mut libc::c_void,
        )
    })))
}

This unsound implementation would create memory issues such as overflow, underflow, or misalignment. The attacker can manipulate the argument size associated with the c_void pointer with large value, which can lead to buffer overflow bug. This can further corrupt the C/C++ code.

This would cause undefined behaviors in Rust. Adversaries can manipulate the arguments to cause memory safety bugs. I am reporting this issue for your attention.