RESPONDERS: Negative caching of local users

This patch adds new option 'neg_cache_locals_timeout' into section
of NSS responder. It allows negative caching of local groups and
users. Default value is 0 which means no caching.

Resolves:
https://fedorahosted.org/sssd/ticket/2928

Reviewed-by: Pavel Březina <pbrezina@redhat.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/src/responder/common/negcache_files.c b/src/responder/common/negcache_files.c
new file mode 100644
index 000000000..1b9a4be43
--- /dev/null
+++ b/src/responder/common/negcache_files.c
@@ -0,0 +1,98 @@
+/*
+   SSSD
+
+   NSS Responder
+
+   Copyright (C) Petr Čech <pcech@redhat.com>	2016
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+#include "util/util.h"
+#include "responder/common/negcache_files.h"
+
+#define BUFFER_SIZE 16384
+
+bool is_user_local_by_name(const char *name)
+{
+    struct passwd pwd = { 0 };
+    struct passwd *pwd_result;
+    char buffer[BUFFER_SIZE];
+    bool is_local = false;
+    int ret;
+
+    ret = getpwnam_r(name, &pwd, buffer, BUFFER_SIZE, &pwd_result);
+    if (ret == EOK && pwd_result != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC, "User %s is a local user\n", name);
+        is_local = true;
+    }
+
+    return is_local;
+}
+
+bool is_user_local_by_uid(uid_t uid)
+{
+    struct passwd pwd = { 0 };
+    struct passwd *pwd_result;
+    char buffer[BUFFER_SIZE];
+    bool is_local = false;
+    int ret;
+
+    ret = getpwuid_r(uid, &pwd, buffer, BUFFER_SIZE, &pwd_result);
+    if (ret == EOK && pwd_result != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC,
+              "User with UID %"SPRIuid" is a local user\n", uid);
+        is_local = true;
+    }
+
+    return is_local;
+}
+
+bool is_group_local_by_name(const char *name)
+{
+    struct group grp = { 0 };
+    struct group *grp_result;
+    char buffer[BUFFER_SIZE];
+    bool is_local = false;
+    int ret;
+
+    ret = getgrnam_r(name, &grp, buffer, BUFFER_SIZE, &grp_result);
+    if (ret == EOK && grp_result != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC, "Group %s is a local group\n", name);
+        is_local = true;
+    }
+
+    return is_local;
+}
+
+bool is_group_local_by_gid(uid_t gid)
+{
+    struct group grp = { 0 };
+    struct group *grp_result;
+    char buffer[BUFFER_SIZE];
+    bool is_local = false;
+    int ret;
+
+    ret = getgrgid_r(gid, &grp, buffer, BUFFER_SIZE, &grp_result);
+    if (ret == EOK && grp_result != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC,
+              "Group with GID %"SPRIgid" is a local group\n", gid);
+        is_local = true;
+    }
+
+    return is_local;
+}