From d6ed04f01dee50499c7df04794a3c810b2831661 Mon Sep 17 00:00:00 2001
From: Alexey Tikhonov <atikhono@redhat.com>
Date: Feb 06 2019 14:47:39 +0000
Subject: Fix error in hostname retrieval


Fix off-by-one error in gethostname() param

Resolves:
https://pagure.io/SSSD/sssd/issue/3865

Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit 170625872a7d53c182ef095b4e5cba29f632c0c4)

---

diff --git a/src/providers/ad/ad_common.c b/src/providers/ad/ad_common.c
index 6d395cf..0d154ca 100644
--- a/src/providers/ad/ad_common.c
+++ b/src/providers/ad/ad_common.c
@@ -458,7 +458,7 @@ ad_get_common_options(TALLOC_CTX *mem_ctx,
      */
     ad_hostname = dp_opt_get_string(opts->basic, AD_HOSTNAME);
     if (ad_hostname == NULL) {
-        gret = gethostname(hostname, HOST_NAME_MAX);
+        gret = gethostname(hostname, sizeof(hostname));
         if (gret != 0) {
             ret = errno;
             DEBUG(SSSDBG_FATAL_FAILURE,
diff --git a/src/providers/data_provider_fo.c b/src/providers/data_provider_fo.c
index 332174e..4d561dc 100644
--- a/src/providers/data_provider_fo.c
+++ b/src/providers/data_provider_fo.c
@@ -239,7 +239,7 @@ errno_t be_fo_set_dns_srv_lookup_plugin(struct be_ctx *be_ctx,
     errno_t ret;
 
     if (hostname == NULL) {
-        ret = gethostname(resolved_hostname, HOST_NAME_MAX);
+        ret = gethostname(resolved_hostname, sizeof(resolved_hostname));
         if (ret != EOK) {
             ret = errno;
             DEBUG(SSSDBG_CRIT_FAILURE,
diff --git a/src/providers/ipa/ipa_common.c b/src/providers/ipa/ipa_common.c
index c71eca8..17d14e6 100644
--- a/src/providers/ipa/ipa_common.c
+++ b/src/providers/ipa/ipa_common.c
@@ -79,7 +79,7 @@ int ipa_get_options(TALLOC_CTX *memctx,
 
     ipa_hostname = dp_opt_get_string(opts->basic, IPA_HOSTNAME);
     if (ipa_hostname == NULL) {
-        ret = gethostname(hostname, HOST_NAME_MAX);
+        ret = gethostname(hostname, sizeof(hostname));
         if (ret != EOK) {
             DEBUG(SSSDBG_CRIT_FAILURE, "gethostname failed [%d][%s].\n", errno,
                       strerror(errno));
diff --git a/src/providers/ldap/ldap_child.c b/src/providers/ldap/ldap_child.c
index 8c11d78..368bb91 100644
--- a/src/providers/ldap/ldap_child.c
+++ b/src/providers/ldap/ldap_child.c
@@ -326,7 +326,7 @@ static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,
     } else {
         char hostname[HOST_NAME_MAX + 1];
 
-        ret = gethostname(hostname, HOST_NAME_MAX);
+        ret = gethostname(hostname, sizeof(hostname));
         if (ret == -1) {
             krberr = KRB5KRB_ERR_GENERIC;
             goto done;
diff --git a/src/providers/ldap/sdap_access.c b/src/providers/ldap/sdap_access.c
index 1ee4dcd..dd04ec5 100644
--- a/src/providers/ldap/sdap_access.c
+++ b/src/providers/ldap/sdap_access.c
@@ -1255,7 +1255,7 @@ static errno_t sdap_access_host(struct ldb_message *user_entry)
         return ERR_ACCESS_DENIED;
     }
 
-    if (gethostname(hostname, HOST_NAME_MAX) == -1) {
+    if (gethostname(hostname, sizeof(hostname)) == -1) {
         DEBUG(SSSDBG_CRIT_FAILURE,
               "Unable to get system hostname. Access denied\n");
         return ERR_ACCESS_DENIED;
diff --git a/src/providers/ldap/sdap_async_sudo_hostinfo.c b/src/providers/ldap/sdap_async_sudo_hostinfo.c
index 42f95df..a3c3e10 100644
--- a/src/providers/ldap/sdap_async_sudo_hostinfo.c
+++ b/src/providers/ldap/sdap_async_sudo_hostinfo.c
@@ -380,7 +380,7 @@ static struct tevent_req *sdap_sudo_get_hostnames_send(TALLOC_CTX *mem_ctx,
     /* get hostname */
 
     errno = 0;
-    ret = gethostname(hostname, HOST_NAME_MAX);
+    ret = gethostname(hostname, sizeof(hostname));
     if (ret != EOK) {
         ret = errno;
         DEBUG(SSSDBG_CRIT_FAILURE, "Unable to retrieve machine hostname "
diff --git a/src/resolv/async_resolv_utils.c b/src/resolv/async_resolv_utils.c
index 8d077d0..f86181b 100644
--- a/src/resolv/async_resolv_utils.c
+++ b/src/resolv/async_resolv_utils.c
@@ -57,7 +57,7 @@ resolv_get_domain_send(TALLOC_CTX *mem_ctx,
 
     if (hostname == NULL) {
         /* use system hostname */
-        ret = gethostname(system_hostname, HOST_NAME_MAX);
+        ret = gethostname(system_hostname, sizeof(system_hostname));
         if (ret) {
             ret = errno;
             DEBUG(SSSDBG_CRIT_FAILURE, "gethostname() failed: [%d]: %s\n",