Fix unaligned pointer read

1 files changed, 27 insertions, 16 deletions

diff --git a/talpid-wireguard/src/wireguard_kernel/parsers.rs b/talpid-wireguard/src/wireguard_kernel/parsers.rs
index 86ecd025b5..a8c16d7d68 100644
--- a/talpid-wireguard/src/wireguard_kernel/parsers.rs
+++ b/talpid-wireguard/src/wireguard_kernel/parsers.rs
@@ -2,7 +2,7 @@ use byteorder::{ByteOrder, NativeEndian};
 use nix::sys::{socket::InetAddr, time::TimeSpec};
 use std::{
     ffi::{CStr, CString},
-    mem,
+    mem::{self, transmute},
     net::IpAddr,
 };
 
@@ -36,30 +36,41 @@ pub fn parse_wg_key(buffer: &[u8]) -> Result<[u8; 32], DecodeError> {
 }
 
 pub fn parse_inet_sockaddr(buffer: &[u8]) -> Result<InetAddr, DecodeError> {
-    if buffer.len() != mem::size_of::<libc::sockaddr_in6>()
-        && buffer.len() != mem::size_of::<libc::sockaddr_in>()
-    {
-        return Err(format!(
+    let wrong_len = || {
+        format!(
             "Unexpected length for sockaddr_in: {}, expected {} or {}",
             buffer.len(),
             mem::size_of::<libc::sockaddr_in6>(),
             mem::size_of::<libc::sockaddr_in>()
         )
-        .into());
-    }
-    let ptr = buffer.as_ptr();
+    };
+
     const AF_INET: u16 = libc::AF_INET as u16;
     const AF_INET6: u16 = libc::AF_INET6 as u16;
 
+    if buffer.len() < size_of::<u16>() {
+        return Err(wrong_len().into());
+    }
+
     match NativeEndian::read_u16(buffer) {
-        AF_INET => unsafe {
-            let sockaddr: *const libc::sockaddr_in = ptr as *const _;
-            Ok(InetAddr::V4(*sockaddr))
-        },
-        AF_INET6 => unsafe {
-            let sockaddr: *const libc::sockaddr_in6 = ptr as *const _;
-            Ok(InetAddr::V6(*sockaddr))
-        },
+        AF_INET => {
+            let buffer: &[u8; size_of::<libc::sockaddr_in>()] =
+                buffer.try_into().map_err(|_| wrong_len())?;
+
+            // SAFETY: sockaddr_in has a defined repr(C) layout and is valid for all bit patterns
+            let sockaddr: libc::sockaddr_in = unsafe { transmute(*buffer) };
+
+            Ok(InetAddr::V4(sockaddr))
+        }
+        AF_INET6 => {
+            let buffer: &[u8; size_of::<libc::sockaddr_in6>()] =
+                buffer.try_into().map_err(|_| wrong_len())?;
+
+            // SAFETY: sockaddr_in6 has a defined repr(C) layout and is valid for all bit patterns
+            let sockaddr: libc::sockaddr_in6 = unsafe { transmute(*buffer) };
+
+            Ok(InetAddr::V6(sockaddr))
+        }
         unexpected_addr_family => {
             Err(format!("Unexpected address family: {unexpected_addr_family}").into())
         }