From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 31 Dec 2021 00:13:00 +0000 (+0900)
Subject: nss-myhostname: do not apply non-zero offset to null pointer
X-Git-Tag: v251-rc1~614^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F21944%2Fhead;p=thirdparty%2Fsystemd.git

nss-myhostname: do not apply non-zero offset to null pointer

Fixes https://github.com/systemd/systemd/issues/21935#issuecomment-1003216503.
---

diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 3536c5fc837..67b1554d278 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -39,10 +39,8 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
         const char *canonical = NULL;
         int n_addresses = 0;
         uint32_t local_address_ipv4;
-        struct local_address *a;
         size_t l, idx, ms;
         char *r_name;
-        unsigned n;
 
         PROTECT_ERRNO;
         BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
@@ -136,7 +134,9 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
         }
 
         /* Fourth, fill actual addresses in, but in backwards order */
-        for (a = addresses + n_addresses - 1, n = 0; (int) n < n_addresses; n++, a--) {
+        for (int i = n_addresses; i > 0; i--) {
+                struct local_address *a = addresses + i - 1;
+
                 r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                 r_tuple->next = r_tuple_prev;
                 r_tuple->name = r_name;