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|
/* PAM Make Home Dir module
This module will create a users home directory if it does not exist
when the session begins. This allows users to be present in central
database (such as nis, kerb or ldap) without using a distributed
file system or pre-creating a large number of directories.
Here is a sample /etc/pam.d/login file for Debian GNU/Linux
2.1:
auth requisite pam_securetty.so
auth sufficient pam_ldap.so
auth required pam_unix.so
auth optional pam_group.so
auth optional pam_mail.so
account requisite pam_time.so
account sufficient pam_ldap.so
account required pam_unix.so
session required pam_mkhomedir.so skel=/etc/skel/ umask=0022
session required pam_unix.so
session optional pam_lastlog.so
password required pam_unix.so
Released under the GNU LGPL version 2 or later
Originally written by Jason Gunthorpe <jgg@debian.org> Feb 1999
Structure taken from pam_lastlogin by Andrew Morgan
<morgan@parc.power.net> 1996
*/
#include "config.h"
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <syslog.h>
/*
* here, we make a definition for the externally accessible function
* in this file (this definition is required for static a module
* but strongly encouraged generally) it is used to instruct the
* modules include file to define the function prototypes.
*/
#define PAM_SM_SESSION
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_modutil.h>
#include <security/pam_ext.h>
/* argument parsing */
#define MKHOMEDIR_DEBUG 020 /* keep quiet about things */
#define MKHOMEDIR_QUIET 040 /* keep quiet about things */
static unsigned int UMask = 0022;
static char SkelDir[BUFSIZ] = "/etc/skel"; /* THIS MODULE IS NOT THREAD SAFE */
static int
_pam_parse (const pam_handle_t *pamh, int flags, int argc, const char **argv)
{
int ctrl = 0;
/* does the appliction require quiet? */
if ((flags & PAM_SILENT) == PAM_SILENT)
ctrl |= MKHOMEDIR_QUIET;
/* step through arguments */
for (; argc-- > 0; ++argv)
{
if (!strcmp(*argv, "silent")) {
ctrl |= MKHOMEDIR_QUIET;
} else if (!strncmp(*argv,"umask=",6)) {
UMask = strtol(*argv+6,0,0);
} else if (!strncmp(*argv,"skel=",5)) {
strncpy(SkelDir,*argv+5,sizeof(SkelDir));
SkelDir[sizeof(SkelDir)-1] = '\0';
} else {
pam_syslog(pamh, LOG_ERR, "unknown option: %s", *argv);
}
}
D(("ctrl = %o", ctrl));
return ctrl;
}
static int
rec_mkdir (const char *dir, mode_t mode)
{
char *cp;
char *parent = strdup (dir);
if (parent == NULL)
return 1;
cp = strrchr (parent, '/');
if (cp != NULL)
{
struct stat st;
*cp++ = '\0';
if (stat (parent, &st) == -1 && errno == ENOENT)
if (rec_mkdir (parent, mode) != 0)
{
free (parent);
return 1;
}
}
free (parent);
if (mkdir (dir, mode) != 0 && errno != EEXIST)
return 1;
return 0;
}
/* Do the actual work of creating a home dir */
static int
create_homedir (pam_handle_t * pamh, int ctrl,
const struct passwd *pwd,
const char *source, const char *dest)
{
char remark[BUFSIZ];
DIR *D;
struct dirent *Dir;
int retval = PAM_AUTH_ERR;
/* Mention what is happening, if the notification fails that is OK */
if ((ctrl & MKHOMEDIR_QUIET) != MKHOMEDIR_QUIET)
(void) pam_info(pamh, "Creating directory '%s'.", dest);
/* Create the new directory */
if (rec_mkdir (dest,0755) != 0)
{
pam_syslog(pamh, LOG_DEBUG, "unable to create directory %s: %m", dest);
return PAM_PERM_DENIED;
}
/* See if we need to copy the skel dir over. */
if ((source == NULL) || (strlen(source) == 0))
{
retval = PAM_SUCCESS;
goto go_out;
}
/* Scan the directory */
D = opendir (source);
if (D == 0)
{
pam_syslog(pamh, LOG_DEBUG, "unable to read directory %s: %m", source);
retval = PAM_PERM_DENIED;
goto go_out;
}
for (Dir = readdir(D); Dir != 0; Dir = readdir(D))
{
int SrcFd;
int DestFd;
int Res;
struct stat St;
#ifndef PATH_MAX
char *newsource = NULL, *newdest = NULL;
/* track length of buffers */
int nslen = 0, ndlen = 0;
int slen = strlen(source), dlen = strlen(dest);
#else
char newsource[PATH_MAX], newdest[PATH_MAX];
#endif
/* Skip some files.. */
if (strcmp(Dir->d_name,".") == 0 ||
strcmp(Dir->d_name,"..") == 0)
continue;
/* Determine what kind of file it is. */
#ifndef PATH_MAX
nslen = slen + strlen(Dir->d_name) + 2;
if (nslen <= 0)
{
retval = PAM_BUF_ERR;
goto go_out;
}
if ((newsource = malloc (nslen)) == NULL)
{
retval = PAM_BUF_ERR;
goto go_out;
}
sprintf(newsource, "%s/%s", source, Dir->d_name);
#else
snprintf(newsource,sizeof(newsource),"%s/%s",source,Dir->d_name);
#endif
if (lstat(newsource,&St) != 0)
#ifndef PATH_MAX
{
free(newsource);
newsource = NULL;
continue;
}
#else
continue;
#endif
/* We'll need the new file's name. */
#ifndef PATH_MAX
ndlen = dlen + strlen(Dir->d_name)+2;
if (ndlen <= 0)
{
retval = PAM_BUF_ERR;
goto go_out;
}
if ((newdest = malloc(ndlen)) == NULL)
{
free (newsource);
retval = PAM_BUF_ERR;
goto go_out;
}
sprintf (newdest, "%s/%s", dest, Dir->d_name);
#else
snprintf (newdest,sizeof (newdest),"%s/%s",dest,Dir->d_name);
#endif
/* If it's a directory, recurse. */
if (S_ISDIR(St.st_mode))
{
retval = create_homedir (pamh, ctrl, pwd, newsource, newdest);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
if (retval != PAM_SUCCESS)
{
closedir(D);
goto go_out;
}
continue;
}
/* If it's a symlink, create a new link. */
if (S_ISLNK(St.st_mode))
{
int pointedlen = 0;
#ifndef PATH_MAX
char *pointed = NULL;
{
int size = 100;
while (1) {
pointed = (char *) malloc(size);
if ( ! pointed ) {
free(newsource);
free(newdest);
return PAM_BUF_ERR;
}
pointedlen = readlink (newsource, pointed, size);
if ( pointedlen < 0 ) break;
if ( pointedlen < size ) break;
free (pointed);
size *= 2;
}
}
if ( pointedlen < 0 )
free(pointed);
else
pointed[pointedlen] = 0;
#else
char pointed[PATH_MAX];
memset(pointed, 0, sizeof(pointed));
pointedlen = readlink(newsource, pointed, sizeof(pointed) - 1);
#endif
if ( pointedlen >= 0 ) {
if(symlink(pointed, newdest) == 0)
{
if (lchown(newdest,pwd->pw_uid,pwd->pw_gid) != 0)
{
pam_syslog(pamh, LOG_DEBUG,
"unable to change perms on link %s: %m", newdest);
closedir(D);
#ifndef PATH_MAX
free(pointed);
free(newsource);
free(newdest);
#endif
return PAM_PERM_DENIED;
}
}
#ifndef PATH_MAX
free(pointed);
#endif
}
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
continue;
}
/* If it's not a regular file, it's probably not a good idea to create
* the new device node, FIFO, or whatever it is. */
if (!S_ISREG(St.st_mode))
{
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
continue;
}
/* Open the source file */
if ((SrcFd = open(newsource,O_RDONLY)) < 0 || fstat(SrcFd,&St) != 0)
{
pam_syslog(pamh, LOG_DEBUG,
"unable to open src file %s: %m", newsource);
closedir(D);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
return PAM_PERM_DENIED;
}
stat(newsource,&St);
/* Open the dest file */
if ((DestFd = open(newdest,O_WRONLY | O_TRUNC | O_CREAT,0600)) < 0)
{
pam_syslog(pamh, LOG_DEBUG,
"unable to open dest file %s: %m", newdest);
close(SrcFd);
closedir(D);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
return PAM_PERM_DENIED;
}
/* Set the proper ownership and permissions for the module. We make
the file a+w and then mask it with the set mask. This preseves
execute bits */
if (fchmod(DestFd,(St.st_mode | 0222) & (~UMask)) != 0 ||
fchown(DestFd,pwd->pw_uid,pwd->pw_gid) != 0)
{
pam_syslog(pamh, LOG_DEBUG,
"unable to change perms on copy %s: %m", newdest);
close(SrcFd);
close(DestFd);
closedir(D);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
return PAM_PERM_DENIED;
}
/* Copy the file */
do
{
Res = pam_modutil_read(SrcFd,remark,sizeof(remark));
if (Res == 0)
continue;
if (Res > 0) {
if (pam_modutil_write(DestFd,remark,Res) == Res)
continue;
}
/* If we get here, pam_modutil_read returned a -1 or
pam_modutil_write returned something unexpected. */
pam_syslog(pamh, LOG_DEBUG, "unable to perform IO: %m");
close(SrcFd);
close(DestFd);
closedir(D);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
return PAM_PERM_DENIED;
}
while (Res != 0);
close(SrcFd);
close(DestFd);
#ifndef PATH_MAX
free(newsource); newsource = NULL;
free(newdest); newdest = NULL;
#endif
}
closedir(D);
retval = PAM_SUCCESS;
go_out:
if (chmod(dest,0777 & (~UMask)) != 0 ||
chown(dest,pwd->pw_uid,pwd->pw_gid) != 0)
{
pam_syslog(pamh, LOG_DEBUG,
"unable to change perms on directory %s: %m", dest);
return PAM_PERM_DENIED;
}
return retval;
}
/* --- authentication management functions (only) --- */
PAM_EXTERN int
pam_sm_open_session (pam_handle_t *pamh, int flags, int argc,
const char **argv)
{
int retval, ctrl;
const void *user;
const struct passwd *pwd;
struct stat St;
/* Parse the flag values */
ctrl = _pam_parse(pamh, flags, argc, argv);
/* Determine the user name so we can get the home directory */
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS || user == NULL || *(const char *)user == '\0')
{
pam_syslog(pamh, LOG_NOTICE, "user unknown");
return PAM_USER_UNKNOWN;
}
/* Get the password entry */
pwd = pam_modutil_getpwnam (pamh, user);
if (pwd == NULL)
{
D(("couldn't identify user %s", user));
return PAM_CRED_INSUFFICIENT;
}
/* Stat the home directory, if something exists then we assume it is
correct and return a success*/
if (stat(pwd->pw_dir,&St) == 0)
return PAM_SUCCESS;
return create_homedir(pamh,ctrl,pwd,SkelDir,pwd->pw_dir);
}
/* Ignore */
PAM_EXTERN
int pam_sm_close_session (pam_handle_t * pamh UNUSED, int flags UNUSED,
int argc UNUSED, const char **argv UNUSED)
{
return PAM_SUCCESS;
}
#ifdef PAM_STATIC
/* static module data */
struct pam_module _pam_mkhomedir_modstruct =
{
"pam_mkhomedir",
NULL,
NULL,
NULL,
pam_sm_open_session,
pam_sm_close_session,
NULL,
};
#endif
|