net2 assumes the layout of std::net::SocketAddrV{4,6} matches libc::sockaddr

[Thomasdezeeuw]

The problem code is here:

net2-rs/src/socket.rs

Lines 87 to 142 in 77a6eb4

	fn addr2raw(addr: &SocketAddr) -> (*const c::sockaddr, c::socklen_t) {
	match *addr {
	SocketAddr::V4(ref a) => {
	(a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
	}
	SocketAddr::V6(ref a) => {
	(a as *const _ as *const _, mem::size_of_val(a) as c::socklen_t)
	}
	}
	}
	fn raw2addr(storage: &c::sockaddr_storage, len: c::socklen_t) -> io::Result<SocketAddr> {
	match storage.ss_family as c_int {
	c::AF_INET => {
	unsafe {
	assert!(len as usize >= mem::size_of::<c::sockaddr_in>());
	let sa = storage as *const _ as *const c::sockaddr_in;
	let bits = c::sockaddr_in_u32(&(*sa));
	let ip = Ipv4Addr::new((bits >> 24) as u8,
	(bits >> 16) as u8,
	(bits >> 8) as u8,
	bits as u8);
	Ok(SocketAddr::V4(SocketAddrV4::new(ip, ::ntoh((*sa).sin_port))))
	}
	}
	c::AF_INET6 => {
	unsafe {
	assert!(len as usize >= mem::size_of::<c::sockaddr_in6>());
	let sa = storage as *const _ as *const c::sockaddr_in6;
	#[cfg(windows)] let arr = (*sa).sin6_addr.u.Byte();
	#[cfg(not(windows))] let arr = (*sa).sin6_addr.s6_addr;
	let ip = Ipv6Addr::new(
	(arr[0] as u16) << 8 | (arr[1] as u16),
	(arr[2] as u16) << 8 | (arr[3] as u16),
	(arr[4] as u16) << 8 | (arr[5] as u16),
	(arr[6] as u16) << 8 | (arr[7] as u16),
	(arr[8] as u16) << 8 | (arr[9] as u16),
	(arr[10] as u16) << 8 | (arr[11] as u16),
	(arr[12] as u16) << 8 | (arr[13] as u16),
	(arr[14] as u16) << 8 | (arr[15] as u16),
	);
	#[cfg(windows)] let sin6_scope_id = *(*sa).u.sin6_scope_id();
	#[cfg(not(windows))] let sin6_scope_id = (*sa).sin6_scope_id;
	Ok(SocketAddr::V6(SocketAddrV6::new(ip,
	::ntoh((*sa).sin6_port),
	(*sa).sin6_flowinfo,
	sin6_scope_id)))
	}
	}
	_ => Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid argument")),
	}
	}

It assumes that the layout of std::net::SocketAddrV{4,6} matches libc::sockaddr, but this can't be assumed.

Related issues: tokio-rs/mio#1386, rust-lang/socket2#119, rust-lang/rust#78802.

Mio has roughly the same code, this was fixed in tokio-rs/mio#1388, for socket2: rust-lang/socket2#120.

[faern]

I'm working on porting my code from the socket2 and mio PRs to this crate.