From 9f1dcb0c0473641730b871dee984016ff19d2c53 Mon Sep 17 00:00:00 2001

From: Maxim Dounin <mdounin@mdounin.ru>

Date: Tue, 25 May 2021 15:17:36 +0300

Subject: [PATCH] Resolver: fixed off-by-one write in ngx_resolver_copy().

Reported by Luis Merino, Markus Vervier, Eric Sesterhenn, X41 D-Sec GmbH.

---

 src/core/ngx_resolver.c | 8 ++++----

 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c

index 7939070102..63b26193df 100644

--- a/src/core/ngx_resolver.c

+++ b/src/core/ngx_resolver.c

@@ -4008,15 +4008,15 @@ ngx_resolver_copy(ngx_resolver_t *r, ngx_str_t *name, u_char *buf, u_char *src,

             n = *src++;

         } else {

+            if (dst != name->data) {

+                *dst++ = '.';

+            }

+

             ngx_strlow(dst, src, n);

             dst += n;

             src += n;

             n = *src++;

-

-            if (n != 0) {

-                *dst++ = '.';

-            }

         }

         if (n == 0) {