CentOS 7上的LDAP身份验证

升级到CentOS 7后，将无法再通过LDAP登录。在CentOS 6中，我使用了工作正常的软件包pam_ldap，但是现在pam_ldap不再可用于新版本的CentOS。

通过ldapsearch进行连接仍然可以正常工作，但是尝试通过ssh进行身份验证无效。

我重新安装了nss-pam-ldapd软件包，并通过authconfig-tui重新配置了身份验证，但是仍然无法正常工作。

在下面，我将用户名替换为user.name，将基本名称替换为dc = sub，dc = example，dc = org。

我的主机操作系统是CentOS7。已安装所有当前可用的更新。

$ uname -a
Linux isfet 3.10.0-123.8.1.el7.x86_64 #1 SMP Mon Sep 22 19:06:58 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

已安装的套件

$ rpm -qa | grep -i ldap
openldap-2.4.39-3.el7.x86_64
nss-pam-ldapd-0.8.13-8.el7.x86_64
openldap-clients-2.4.39-3.el7.x86_64

/etc/openldap/ldap.conf的内容

URI ldap://172.16.64.25
BASE dc=sub,dc=example,dc=org

/etc/nslcd.conf的内容

ldap_version 3
uri ldap://172.16.64.25
base dc=sub,dc=example,dc=org
ssl no

/ var / log / secure的输出

Oct  6 12:12:16 isfet sshd[3937]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=172.16.64.1  user=user.name
Oct  6 12:12:17 isfet sshd[3937]: Failed password for user.name from 172.16.64.1 port 18877 ssh2

/var/log/audit/audit.log的输出

type=USER_AUTH msg=audit(1412590243.286:364): pid=3912 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:authentication acct="user.name" exe="/usr/sbin/sshd" hostname=172.16.64.1 addr=172.16.64.1 terminal=ssh res=failed'
type=USER_AUTH msg=audit(1412590243.287:365): pid=3912 uid=0 auid=4294967295 ses=4294967295 msg='op=password acct="user.name" exe="/usr/sbin/sshd" hostname=? addr=172.16.64.1 terminal=ssh res=failed'

ldapserach命令的输出

$ ldapsearch -H ldap://172.16.64.25/ -D cn=Manager,dc=sub,dc=example,dc=org -W -x -b dc=sub,dc=example,dc=org -d1

ldap_url_parse_ext(ldap://172.16.64.25/)
ldap_create
ldap_url_parse_ext(ldap://172.16.64.25:389/??base)
Enter LDAP Password:
ldap_sasl_bind
ldap_send_initial_request
ldap_new_connection 1 1 0
ldap_int_open_connection
ldap_connect_to_host: TCP 172.16.64.25:389
ldap_new_socket: 3
ldap_prepare_socket: 3
ldap_connect_to_host: Trying 172.16.64.25:389
ldap_pvt_connect: fd: 3 tm: -1 async: 0
attempting to connect:
connect success
ldap_open_defconn: successful
ldap_send_server_request
ber_scanf fmt ({it) ber:
ber_scanf fmt ({i) ber:
ber_flush2: 61 bytes to sd 3
ldap_result ld 0x7f9b07402110 msgid 1
wait4msg ld 0x7f9b07402110 msgid 1 (infinite timeout)
wait4msg continue ld 0x7f9b07402110 msgid 1 all 1
** ld 0x7f9b07402110 Connections:
* host: 172.16.64.25  port: 389  (default)
  refcnt: 2  status: Connected
  last used: Mon Oct  6 12:04:38 2014


** ld 0x7f9b07402110 Outstanding Requests:
 * msgid 1,  origid 1, status InProgress
   outstanding referrals 0, parent count 0
  ld 0x7f9b07402110 request count 1 (abandoned 0)
** ld 0x7f9b07402110 Response Queue:
   Empty
  ld 0x7f9b07402110 response count 0
ldap_chkResponseList ld 0x7f9b07402110 msgid 1 all 1
ldap_chkResponseList returns ld 0x7f9b07402110 NULL
ldap_int_select
read1msg: ld 0x7f9b07402110 msgid 1 all 1
ber_get_next
ber_get_next: tag 0x30 len 50 contents:
read1msg: ld 0x7f9b07402110 msgid 1 message type bind
ber_scanf fmt ({eAA) ber:
read1msg: ld 0x7f9b07402110 0 new referrals
read1msg:  mark request completed, ld 0x7f9b07402110 msgid 1
request done: ld 0x7f9b07402110 msgid 1
res_errno: 0, res_error: <>, res_matched: <cn=Manager,dc=sub,dc=example,dc=org>
ldap_free_request (origid 1, msgid 1)
ldap_parse_result
ber_scanf fmt ({iAA) ber:
ber_scanf fmt (}) ber:
ldap_msgfree
ldap_err2string
ldap_bind: Success (0)
        matched DN: cn=Manager,dc=sub,dc=example,dc=org
...

_ / etc / pam.d / password-auth的内容

auth        required      pam_env.so
auth        sufficient    pam_unix.so nullok try_first_pass
auth        requisite     pam_succeed_if.so uid >= 1000 quiet_success
auth        sufficient    pam_ldap.so use_first_pass
auth        required      pam_deny.so

account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 1000 quiet
account     [default=bad success=ok user_unknown=ignore] pam_ldap.so
account     required      pam_permit.so

password    requisite     pam_pwquality.so try_first_pass retry=3 type=
password    sufficient    pam_unix.so sha512 shadow nullok try_first_pass use_authtok
password    sufficient    pam_ldap.so use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
-session     optional      pam_systemd.so
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_ldap.so

_ / etc / pam.d / system-auth的内容

auth        required      pam_env.so
auth        sufficient    pam_unix.so nullok try_first_pass
auth        requisite     pam_succeed_if.so uid >= 1000 quiet_success
auth        sufficient    pam_ldap.so use_first_pass
auth        required      pam_deny.so

account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 1000 quiet
account     [default=bad success=ok user_unknown=ignore] pam_ldap.so
account     required      pam_permit.so

password    requisite     pam_pwquality.so try_first_pass retry=3 type=
password    sufficient    pam_unix.so sha512 shadow nullok try_first_pass use_authtok
password    sufficient    pam_ldap.so use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
-session     optional      pam_systemd.so
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_ldap.so

在调试模式下运行nslcd会显示问题：

$ $(which nslcd) -d
...
nslcd: [8b4567] <authc="user.name"> DEBUG: myldap_search(base="dc=sub,dc=example,dc=org", filter="(&(objectClass=posixAccount)(uid=user.name))")
...
nslcd: [8b4567] <authc="user.name"> DEBUG: ldap_result(): end of results (0 total)
nslcd: [8b4567] <authc="user.name"> DEBUG: "user.name": user not found: No such object
...

nslcd默认设置过滤器。无法删除此过滤器或将其设置为空白。

因为我的LDAP用户都没有一个名为posixAccount的objectClass，所以找不到用户，并且登录被拒绝。

要解决此问题，我必须用自己的过滤器覆盖此过滤器。因为我正在寻找uid，所以在始终要搜索的属性上设置过滤器很有用。

我的/etc/nslcd.conf的新内容：

filter passwd (uid=*)
uri ldap://172.16.64.25
base dc=sub,dc=example,dc=org
ssl no

更改nslcd.conf后，我必须重新启动服务nslcd：systemctl restart nslcd

资料来源： http : //lists.arthurdejong.org/nss-pam-ldapd-users/2014/msg00025.html

。

对于CentOS 7上的_nss-pam-ldapd-0.8.13-8.el7.x86_64_来说，这似乎是一个问题！

$ nslcd -V
nss-pam-ldapd 0.8.13

我试图在CentOS 6上重现该问题，但是在此nss-pam-ldapd上有pam_ldap的依赖关系，后者在/etc/pam_ldap.conf中具有其配置文件，并且似乎在工作方式上不使用/etc/nslcd.conf。在CentOS 7上。