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/******************************************************************************
* A module for Linux-PAM that will set the default namespace after
* establishing a session via PAM.
*
* (C) Copyright IBM Corporation 2005
* (C) Copyright Red Hat 2006
* All Rights Reserved.
*
* Written by: Janak Desai <janak@us.ibm.com>
* With Revisions by: Steve Grubb <sgrubb@redhat.com>
* Derived from a namespace setup patch by Chad Sellers <cdselle@tycho.nsa.gov>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#if !(defined(linux))
#error THIS CODE IS KNOWN TO WORK ONLY ON LINUX !!!
#endif
#include "config.h"
#include <stdio.h>
#include <stdio_ext.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <errno.h>
#include <syslog.h>
#include <dlfcn.h>
#include <stdarg.h>
#include <pwd.h>
#include <grp.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <sys/mount.h>
#include <sys/wait.h>
#include <libgen.h>
#include <fcntl.h>
#include <sched.h>
#include <glob.h>
#include <locale.h>
#include "security/pam_modules.h"
#include "security/pam_modutil.h"
#include "security/pam_ext.h"
#include "md5.h"
#ifdef WITH_SELINUX
#include <selinux/selinux.h>
#include <selinux/get_context_list.h>
#include <selinux/context.h>
#include <selinux/label.h>
#endif
#ifndef CLONE_NEWNS
#define CLONE_NEWNS 0x00020000 /* Flag to create new namespace */
#endif
/* mount flags for mount_private */
#ifndef MS_REC
#define MS_REC (1<<14)
#endif
#ifndef MS_PRIVATE
#define MS_PRIVATE (1<<18)
#endif
#ifndef MS_SLAVE
#define MS_SLAVE (1<<19)
#endif
/*
* Module defines
*/
#ifndef SECURECONF_DIR
#define SECURECONF_DIR "/etc/security/"
#endif
#define PAM_NAMESPACE_CONFIG (SECURECONF_DIR "namespace.conf")
#define NAMESPACE_INIT_SCRIPT (SECURECONF_DIR "namespace.init")
#define NAMESPACE_D_DIR (SECURECONF_DIR "namespace.d/")
#define NAMESPACE_D_GLOB (SECURECONF_DIR "namespace.d/*.conf")
/* module flags */
#define PAMNS_DEBUG 0x00000100 /* Running in debug mode */
#define PAMNS_SELINUX_ENABLED 0x00000400 /* SELinux is enabled */
#define PAMNS_CTXT_BASED_INST 0x00000800 /* Context based instance needed */
#define PAMNS_GEN_HASH 0x00002000 /* Generate md5 hash for inst names */
#define PAMNS_IGN_CONFIG_ERR 0x00004000 /* Ignore format error in conf file */
#define PAMNS_IGN_INST_PARENT_MODE 0x00008000 /* Ignore instance parent mode */
#define PAMNS_UNMOUNT_ON_CLOSE 0x00010000 /* Unmount at session close */
#define PAMNS_USE_CURRENT_CONTEXT 0x00020000 /* use getcon instead of getexeccon */
#define PAMNS_USE_DEFAULT_CONTEXT 0x00040000 /* use get_default_context instead of getexeccon */
#define PAMNS_MOUNT_PRIVATE 0x00080000 /* Make the polydir mounts private */
/* polydir flags */
#define POLYDIR_EXCLUSIVE 0x00000001 /* polyinstatiate exclusively for override uids */
#define POLYDIR_CREATE 0x00000002 /* create the polydir */
#define POLYDIR_NOINIT 0x00000004 /* no init script */
#define POLYDIR_SHARED 0x00000008 /* share context/level instances among users */
#define POLYDIR_ISCRIPT 0x00000010 /* non default init script */
#define POLYDIR_MNTOPTS 0x00000020 /* mount options for tmpfs mount */
#define NAMESPACE_MAX_DIR_LEN 80
#define NAMESPACE_POLYDIR_DATA "pam_namespace:polydir_data"
#define NAMESPACE_PROTECT_DATA "pam_namespace:protect_data"
/*
* Polyinstantiation method options, based on user, security context
* or both
*/
enum polymethod {
NONE,
USER,
CONTEXT,
LEVEL,
TMPDIR,
TMPFS
};
/*
* Depending on the application using this namespace module, we
* may need to unmount previously bind mounted instance directory.
* Applications such as login and sshd, that establish a new
* session unmount of instance directory is not needed. For applications
* such as su and newrole, that switch the identity, this module
* has to unmount previous instance directory first and re-mount
* based on the new identity. For other trusted applications that
* just want to undo polyinstantiation, only unmount of previous
* instance directory is needed.
*/
enum unmnt_op {
NO_UNMNT,
UNMNT_REMNT,
UNMNT_ONLY,
};
/*
* Structure that holds information about a directory to polyinstantiate
*/
struct polydir_s {
char dir[PATH_MAX]; /* directory to polyinstantiate */
char rdir[PATH_MAX]; /* directory to unmount (based on RUSER) */
char instance_prefix[PATH_MAX]; /* prefix for instance dir path name */
enum polymethod method; /* method used to polyinstantiate */
unsigned int num_uids; /* number of override uids */
uid_t *uid; /* list of override uids */
unsigned int flags; /* polydir flags */
char *init_script; /* path to init script */
char *mount_opts; /* mount options for tmpfs mount */
unsigned long mount_flags; /* mount flags for tmpfs mount */
uid_t owner; /* user which should own the polydir */
gid_t group; /* group which should own the polydir */
mode_t mode; /* mode of the polydir */
struct polydir_s *next; /* pointer to the next polydir entry */
};
struct protect_dir_s {
char *dir; /* protected directory */
struct protect_dir_s *next; /* next entry */
};
struct instance_data {
pam_handle_t *pamh; /* The pam handle for this instance */
struct polydir_s *polydirs_ptr; /* The linked list pointer */
struct protect_dir_s *protect_dirs; /* The pointer to stack of mount-protected dirs */
char user[LOGIN_NAME_MAX]; /* User name */
char ruser[LOGIN_NAME_MAX]; /* Requesting user name */
uid_t uid; /* The uid of the user */
gid_t gid; /* The gid of the user's primary group */
uid_t ruid; /* The uid of the requesting user */
unsigned long flags; /* Flags for debug, selinux etc */
};
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