为什么 pam_mount 要求输入密码？

Question

我使用该pam-auth-update工具来启用一些 pam 配置文件：

 PAM configuration 
 PAM profiles to enable:
    [*] encfs encrypted home directories           
    [*] Unix authentication                             
    [*] Mount volumes for user                         
    [*] GNOME Keyring Daemon - Login keyring management  
    [*] ConsoleKit Session Management

所有功能都按预期工作，但有一件事——该Mount volumes for user选项似乎会影响su命令。

我将以下行添加到/etc/security/pam_mount.conf.xml文件中：

<volume user="morfik" fstype="fuse" path="encfs#/media/Server/Dropbox.encfs/Dropbox/encrypted" mountpoint="/media/Server/Dropbox" />

当我输入终端su morfik（以 root 身份）时，不应该有任何密码提示，但我看到的是：

# su morfik
reenter password for pam_mount:

如果我取消选中Mount volumes for user上面菜单中的选项，一切似乎都是文件，然后reenter password消失了。我尝试处理/etc/pam.d/文件，但我对 PAM 没有任何经验，而且我无法让它工作。

有谁知道这些文件中必须更改什么？

更新#1

这是/etc/pam.d目录的内容：

# ls -al /etc/pam.d/
total 104K
drwxr-xr-x   2 root root 4.0K Mar 21 16:21 ./
drwxr-xr-x 153 root root  12K Mar 21 16:11 ../
-rw-r--r--   1 root root  197 Sep  8  2013 atd
-rw-r--r--   1 root root  384 May 25  2012 chfn
-rw-r--r--   1 root root   92 May 25  2012 chpasswd
-rw-r--r--   1 root root  581 May 25  2012 chsh
-rw-r--r--   1 root root 1.2K Mar 20 17:35 common-account
-rw-r--r--   1 root root 1.3K Mar 20 17:35 common-auth
-rw-r--r--   1 root root 1.5K Mar 20 17:35 common-password
-rw-r--r--   1 root root 1.3K Mar 20 17:35 common-session
-rw-r--r--   1 root root 1.2K Mar 20 17:35 common-session-noninteractive
-rw-r--r--   1 root root  527 Jul  3  2012 cron
-rw-r--r--   1 root root   69 Jul 16  2013 cups-daemon
-rw-r--r--   1 root root 4.8K Mar  5 10:18 login
-rw-r--r--   1 root root   92 May 25  2012 newusers
-rw-r--r--   1 root root  520 Jul 22  2008 other
-rw-r--r--   1 root root  147 Feb 13 07:15 passwd
-rw-r--r--   1 root root  255 Oct 15 18:40 polkit-1
-rw-r--r--   1 root root   84 Dec 27 12:40 samba
-rw-r--r--   1 root root 2.1K Feb 15 03:11 sshd
-rw-r--r--   1 root root 2.3K May 25  2012 su
-rw-r--r--   1 root root   95 Jan 15 22:58 sudo
-rw-r--r--   1 root root  108 Oct 19 23:42 xscreensaver

没有文件/etc/pam.d/system-auth。

我检查了pam_mount它们的内容中有哪些文件，我得到了这个：

# egrep -i pam_mount *
common-auth:auth        optional        pam_mount.so
common-session:session  optional        pam_mount.so

文件内容：

#
# /etc/pam.d/common-auth - authentication settings common to all services
#
# This file is included from other service-specific PAM config files,
# and should contain a list of the authentication modules that define
# the central authentication scheme for use on the system
# (e.g., /etc/shadow, LDAP, Kerberos, etc.).  The default is to use the
# traditional Unix authentication mechanisms.
#
# As of pam 1.0.1-6, this file is managed by pam-auth-update by default.
# To take advantage of this, it is recommended that you configure any
# local modules either before or after the default block, and use
# pam-auth-update to manage selection of other modules.  See
# pam-auth-update(8) for details.

# here are the per-package modules (the "Primary" block)
auth    sufficient              pam_encfs.so 
auth    [success=1 default=ignore]  pam_unix.so nullok_secure try_first_pass
# here's the fallback if no module succeeds
auth    requisite           pam_deny.so
# prime the stack with a positive return value if there isn't one already;
# this avoids us returning an error just because nothing sets a success code
# since the modules above will each just jump around
auth    required            pam_permit.so
# and here are more per-package modules (the "Additional" block)
auth    optional    pam_mount.so 
# end of pam-auth-update config

和：

#
# /etc/pam.d/common-session - session-related modules common to all services
#
# This file is included from other service-specific PAM config files,
# and should contain a list of modules that define tasks to be performed
# at the start and end of sessions of *any* kind (both interactive and
# non-interactive).
#
# As of pam 1.0.1-6, this file is managed by pam-auth-update by default.
# To take advantage of this, it is recommended that you configure any
# local modules either before or after the default block, and use
# pam-auth-update to manage selection of other modules.  See
# pam-auth-update(8) for details.

# here are the per-package modules (the "Primary" block)
session [default=1]         pam_permit.so
# here's the fallback if no module succeeds
session requisite           pam_deny.so
# prime the stack with a positive return value if there isn't one already;
# this avoids us returning an error just because nothing sets a success code
# since the modules above will each just jump around
session required            pam_permit.so
# and here are more per-package modules (the "Additional" block)
session required    pam_unix.so 
session optional    pam_mount.so 
session optional            pam_ck_connector.so nox11
# end of pam-auth-update config

更新#2

我正在使用 Debian 测试。我试图改变 的位置pam_mount，但它总是一样的。我已经阅读了手册的一些部分，并且有类似的内容：

 When "sufficient" is used in the second column, you must make sure that
   pam_mount is added before this entry. Otherwise pam_mount will not  get
   executed  should  a  previous  PAM module succeed. Also be aware of the
   "include" statements. These make PAM look into the specified  file.  If
   there is a "sufficient" statement, then the pam_mount entry must either
   be in the included file before the "sufficient" statement or before the
   "include" statement.

我什pam_mount至添加到/etc/pam.d/su文件中以检查这是否有任何区别，但这并不重要。如果pam_mount首先，就像他们说的，而不是密码提示，pam_mount password当我登录到我的系统时得到提示，当我尝试时它仍然要求输入密码su morfik

Answer 1

遇到了同样的问题。

事实证明，通过在配置文件 ( ) 中添加disable_interactive旁边的选项可以解决问题。pam_mount.so/etc/pam.d/common-{auth,session}

它紧随其后pam_mount.so，选项之间用空格分隔（从so文件名到每两个选项之间）。

当pam_mount.so代码在登录时执行时，它将从堆栈顶部接收密码并使用该密码来解密您的卷。

当您从 root 会话进行操作时su，不需要密码，因此pam_mount.so不会获得任何密码。因此，如果没有该disable_interactive选项，它将尝试获取密码。

幸运的是，正如您从https://sourceforge.net/p/pam-mount/pam-mount/ci/master/tree/src/pam_mount.c中看到的，第 493 行，pam_mount即使没有密码也会尝试继续，这很好，因为如果卷已解锁并安装，则不需要密码。