Unsound usages of unsafe implementation about c_void

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

Unsafe pointer conversion is found at: src/netmap_user.rs:16

pub unsafe fn _NETMAP_OFFSET<T, U>(ptr: *mut U, offset: isize) -> *mut T {
    ((ptr as *mut c_char).offset(offset) as *mut c_void) as *mut T
}

This unsound implementation would create memory issues such as overflow, underflow, or misalignment, since the type is converted to c_void (1 byte, 8 bits). The attacker can manipulate the argument offset associated with the c_void pointer with a large value, as well as T and U, which can lead to a buffer overflow bug.

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

src/netmap_user.rs:16 と _NETMAP_OFFSET 関数から始め、続いて raw-pointer offset、アラインメント、境界に関する Rust の未定義動作の要件を確認してください。関数の呼び出し元と照合して static-analyzer のレポートを検証し、報告された変換によって主張されているメモリ安全性の問題が発生し得るかどうかを判断してください。調査結果が明確に解決され、適切に検証されれば完了です。