From 3dfab6fb6443983d22fa075920a3d66dd54817c7 Mon Sep 17 00:00:00 2001
From: LinkTed <LinkTed@users.noreply.github.com>
Date: Tue, 25 Aug 2020 18:38:25 +0200
Subject: [PATCH] Add integer overflow check

---
 library/std/src/sys/unix/ext/net/ancillary.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/library/std/src/sys/unix/ext/net/ancillary.rs b/library/std/src/sys/unix/ext/net/ancillary.rs
index 142526f3a41..8ba389762fb 100644
--- a/library/std/src/sys/unix/ext/net/ancillary.rs
+++ b/library/std/src/sys/unix/ext/net/ancillary.rs
@@ -72,7 +72,15 @@ fn add_to_ancillary_data<T: Clone>(
     cmsg_level: libc::c_int,
     cmsg_type: libc::c_int,
 ) -> bool {
-    let len = (source.len() * size_of::<T>()) as u32;
+    let len = if let Some(len) = source.len().checked_mul(size_of::<T>()) {
+        if let Ok(len) = u32::try_from(len) {
+            len
+        } else {
+            return false;
+        }
+    } else {
+        return false;
+    };
 
     unsafe {
         let additional_space = libc::CMSG_SPACE(len) as usize;