diff --git a/library/std/src/os/unix/net/addr.rs b/library/std/src/os/unix/net/addr.rs
index e13f44d6fc9bd..92f30ae4605cb 100644
--- a/library/std/src/os/unix/net/addr.rs
+++ b/library/std/src/os/unix/net/addr.rs
@@ -255,12 +255,10 @@ impl SocketAddr {
         } else if self.addr.sun_path[0] == 0 {
             AddressKind::Abstract(ByteStr::from_bytes(&path[1..len]))
         } else {
-            // the value returned by getsockname(2) and similar on QNX7.1 and
-            // QNX8 does not count the NUL byte terminator of the path string,
-            // which matches the behavior of the SUN_LEN macro in libc, but
-            // other OSes do count the NUL byte so adjust accordingly
-            let end =
-                if cfg!(any(target_os = "qnx", target_env = "nto71")) { len } else { len - 1 };
+            // linux adds a trailing NUL and counts it in the length, freebsd, netbsd
+            // and qnx do not, and a caller may bind(2) without one either. unix(7)
+            // gives the portable rule: strnlen(sun_path, len - offsetof(sun_path))
+            let end = core::slice::memchr::memchr(0, &path[..len]).unwrap_or(len);
             AddressKind::Pathname(OsStr::from_bytes(&path[..end]).as_ref())
         }
     }
diff --git a/library/std/src/os/unix/net/tests.rs b/library/std/src/os/unix/net/tests.rs
index 3ba4b44d2f1ef..9c3119e787b33 100644
--- a/library/std/src/os/unix/net/tests.rs
+++ b/library/std/src/os/unix/net/tests.rs
@@ -29,6 +29,29 @@ fn sock_addr_from_pathname() {
     assert_eq!(address.as_pathname(), Some(Path::new("/path/to/socket")));
 }
 
+// the trailing NUL is not counted in the reported length on freebsd, netbsd
+// and qnx, and a caller may bind(2) without one anywhere
+#[test]
+fn sock_addr_without_trailing_nul() {
+    const PATH: &[u8] = b"/path/to/socket";
+
+    // SAFETY: all zeros is a valid representation for `sockaddr_un`.
+    let mut addr: libc::sockaddr_un = unsafe { crate::mem::zeroed() };
+    addr.sun_family = libc::AF_UNIX as libc::sa_family_t;
+    for (dst, &src) in addr.sun_path.iter_mut().zip(PATH) {
+        *dst = src as _;
+    }
+    let offset = crate::mem::offset_of!(libc::sockaddr_un, sun_path);
+
+    // length excluding the NUL, as reported by freebsd, netbsd and qnx
+    let address = or_panic!(SocketAddr::from_parts(addr, (offset + PATH.len()) as _));
+    assert_eq!(address.as_pathname(), Some(Path::new("/path/to/socket")));
+
+    // length including the NUL, as reported by linux
+    let address = or_panic!(SocketAddr::from_parts(addr, (offset + PATH.len() + 1) as _));
+    assert_eq!(address.as_pathname(), Some(Path::new("/path/to/socket")));
+}
+
 #[test]
 #[cfg_attr(target_os = "android", ignore)] // Android SELinux rules prevent creating Unix sockets
 #[cfg_attr(target_os = "vxworks", ignore = "Unix sockets are not implemented in VxWorks")]