From 7c591a961c23ff363149bc4a5bcd0ae212c849d3 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Tue, 24 May 2022 17:26:29 +0200
Subject: [PATCH] dnsdist: Accept large buffers in getMACAddress()

---
 pdns/misc.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pdns/misc.cc b/pdns/misc.cc
index 4b682489a7..ebcd717447 100644
--- a/pdns/misc.cc
+++ b/pdns/misc.cc
@@ -1232,10 +1232,11 @@ int getMACAddress(const ComboAddress& ca, char* dest, size_t destLen)
         }
         else if (rtatp->rta_type == NDA_LLADDR) {
           if (foundIP) {
-            if ((rtatp->rta_len - sizeof(struct rtattr)) != destLen) {
-              return EINVAL;
+            size_t addrLen = rtatp->rta_len - sizeof(struct rtattr);
+            if (addrLen > destLen) {
+              return ENOBUFS;
             }
-            memcpy(dest, reinterpret_cast<const char*>(rtatp) + sizeof(struct rtattr), destLen);
+            memcpy(dest, reinterpret_cast<const char*>(rtatp) + sizeof(struct rtattr), addrLen);
             foundMAC = true;
             done = true;
             break;
-- 
2.47.2