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.

Commencez par src/netmap_user.rs:16 et la fonction _NETMAP_OFFSET, puis examinez les exigences de Rust concernant le comportement indéfini pour l’offset de pointeurs bruts, l’alignement et les limites. Validez le rapport de l’analyseur statique en examinant les appelants de la fonction et déterminez si la conversion signalée peut produire le problème de sûreté mémoire revendiqué. La tâche est terminée lorsque le constat dispose d’une résolution claire et d’une vérification appropriée.