From 9e61ba19e9cda344aa2094e9a671d98076164163 Mon Sep 17 00:00:00 2001
From: mlugg <mlugg@mlugg.co.uk>
Date: Mon, 12 Jun 2023 22:00:56 +0100
Subject: [PATCH] std.crypto.tls.Client: fix @memcpy crash in
 limitedOverlapCopy

Resolves: #15928
---
 lib/std/crypto/tls/Client.zig | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/std/crypto/tls/Client.zig b/lib/std/crypto/tls/Client.zig
index 2745bd4e6f..5b9b00538a 100644
--- a/lib/std/crypto/tls/Client.zig
+++ b/lib/std/crypto/tls/Client.zig
@@ -1256,10 +1256,8 @@ fn limitedOverlapCopy(frag: []u8, in: usize) void {
         // A single, non-overlapping memcpy suffices.
         @memcpy(frag[0..first.len], first);
     } else {
-        // Need two memcpy calls because one alone would overlap.
-        @memcpy(frag[0..in], first[0..in]);
-        const leftover = first.len - in;
-        @memcpy(frag[in..][0..leftover], first[in..][0..leftover]);
+        // One memcpy call would overlap, so just do this instead.
+        std.mem.copyForwards(u8, frag, first);
     }
 }