From 8e6656c974ac05bb52607014bb4c30b87f4abd8b Mon Sep 17 00:00:00 2001
From: Alexey Tikhonov <atikhono@redhat.com>
Date: Mar 27 2019 21:43:46 +0000
Subject: negcache_files: got rid of large array on stack


Removed large buffer from function stack.
It is safe to use single (static) global buffer since:
1) Responders are single threaded
2) Code doesn't use content of this buffer anyway

Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

---

diff --git a/src/responder/common/negcache_files.c b/src/responder/common/negcache_files.c
index 85a7065..f22796a 100644
--- a/src/responder/common/negcache_files.c
+++ b/src/responder/common/negcache_files.c
@@ -24,12 +24,12 @@
 #include "responder/common/negcache_files.h"
 
 #define BUFFER_SIZE 16384
+static char s_nss_buffer[BUFFER_SIZE];
 
 bool is_user_local_by_name(const struct sss_nss_ops *ops, const char *name)
 {
     struct passwd pwd = { 0 };
     int errnop;
-    char buffer[BUFFER_SIZE];
     enum nss_status ret;
     char *shortname = NULL;
     int parse_ret;
@@ -39,7 +39,7 @@ bool is_user_local_by_name(const struct sss_nss_ops *ops, const char *name)
         return false;
     }
 
-    ret = ops->getpwnam_r(shortname, &pwd, buffer, BUFFER_SIZE, &errnop);
+    ret = ops->getpwnam_r(shortname, &pwd, s_nss_buffer, BUFFER_SIZE, &errnop);
     talloc_free(shortname);
     if (ret == NSS_STATUS_SUCCESS) {
         DEBUG(SSSDBG_TRACE_FUNC, "User %s is a local user\n", name);
@@ -53,10 +53,9 @@ bool is_user_local_by_uid(const struct sss_nss_ops *ops, uid_t uid)
 {
     struct passwd pwd = { 0 };
     int errnop;
-    char buffer[BUFFER_SIZE];
     enum nss_status ret;
 
-    ret = ops->getpwuid_r(uid, &pwd, buffer, BUFFER_SIZE, &errnop);
+    ret = ops->getpwuid_r(uid, &pwd, s_nss_buffer, BUFFER_SIZE, &errnop);
     if (ret == NSS_STATUS_SUCCESS) {
         DEBUG(SSSDBG_TRACE_FUNC,
               "User with UID %"SPRIuid" is a local user\n", uid);
@@ -70,7 +69,6 @@ bool is_group_local_by_name(const struct sss_nss_ops *ops, const char *name)
 {
     struct group grp = { 0 };
     int errnop;
-    char buffer[BUFFER_SIZE];
     enum nss_status ret;
     char *shortname = NULL;
     int parse_ret;
@@ -80,7 +78,7 @@ bool is_group_local_by_name(const struct sss_nss_ops *ops, const char *name)
         return false;
     }
 
-    ret = ops->getgrnam_r(shortname, &grp, buffer, BUFFER_SIZE, &errnop);
+    ret = ops->getgrnam_r(shortname, &grp, s_nss_buffer, BUFFER_SIZE, &errnop);
     talloc_free(shortname);
     if (ret == NSS_STATUS_SUCCESS) {
         DEBUG(SSSDBG_TRACE_FUNC, "Group %s is a local group\n", name);
@@ -94,10 +92,9 @@ bool is_group_local_by_gid(const struct sss_nss_ops *ops, uid_t gid)
 {
     struct group grp = { 0 };
     int errnop;
-    char buffer[BUFFER_SIZE];
     enum nss_status ret;
 
-    ret = ops->getgrgid_r(gid, &grp, buffer, BUFFER_SIZE, &errnop);
+    ret = ops->getgrgid_r(gid, &grp, s_nss_buffer, BUFFER_SIZE, &errnop);
     if (ret == NSS_STATUS_SUCCESS) {
         DEBUG(SSSDBG_TRACE_FUNC,
               "Group with GID %"SPRIgid" is a local group\n", gid);