From: Luca Boccassi <luca.boccassi@gmail.com>
Date: Sat, 11 Apr 2026 21:15:52 +0000 (+0100)
Subject: nss-myhostname: add more INC_SAFE for buffer index accumulation
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1afc0c6c608e75e6fccba13cc4f36039b0a7ae6e;p=thirdparty%2Fsystemd.git

nss-myhostname: add more INC_SAFE for buffer index accumulation

Use overflow-safe INC_SAFE() instead of raw addition for idx
accumulation, so that Coverity can see the addition is checked.

CID#1548028

Follow-up for a05483a921a518fd283e7cb32dc8c8e816b2ab2c
---

diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 601a4198dd8..b4a9775ef35 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -230,7 +230,7 @@ static enum nss_status fill_in_hostent(
         if (additional) {
                 r_alias = buffer + idx;
                 memcpy(r_alias, additional, l_additional+1);
-                idx += ALIGN(l_additional+1);
+                assert_se(INC_SAFE(&idx, ALIGN(l_additional+1)));
         }
 
         /* Second, create aliases array */
@@ -258,14 +258,14 @@ static enum nss_status fill_in_hostent(
                 }
 
                 assert(i == c);
-                idx += c*ALIGN(alen);
+                assert_se(INC_SAFE(&idx, c*ALIGN(alen)));
 
         } else if (af == AF_INET) {
                 *(uint32_t*) r_addr = local_address_ipv4;
-                idx += ALIGN(alen);
+                assert_se(INC_SAFE(&idx, ALIGN(alen)));
         } else if (socket_ipv6_is_enabled()) {
                 memcpy(r_addr, LOCALADDRESS_IPV6, FAMILY_ADDRESS_SIZE(AF_INET6));
-                idx += ALIGN(alen);
+                assert_se(INC_SAFE(&idx, ALIGN(alen)));
         }
 
         /* Fourth, add address pointer array */
@@ -277,15 +277,15 @@ static enum nss_status fill_in_hostent(
                         ((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen);
 
                 ((char**) r_addr_list)[i] = NULL;
-                idx += (c+1) * sizeof(char*);
+                assert_se(INC_SAFE(&idx, (c+1) * sizeof(char*)));
 
         } else if (af == AF_INET || socket_ipv6_is_enabled()) {
                 ((char**) r_addr_list)[0] = r_addr;
                 ((char**) r_addr_list)[1] = NULL;
-                idx += 2 * sizeof(char*);
+                assert_se(INC_SAFE(&idx, 2 * sizeof(char*)));
         } else {
                 ((char**) r_addr_list)[0] = NULL;
-                idx += sizeof(char*);
+                assert_se(INC_SAFE(&idx, sizeof(char*)));
         }
 
         /* Verify the size matches */