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/******************************************************************************
* A module for Linux-PAM that will set the default security context after login
* via PAM.
*
* Copyright (c) 2003 Red Hat, Inc.
* Written by Dan Walsh <dwalsh@redhat.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/************************************************************************
*
* All PAM code goes in this section.
*
************************************************************************/
#include "config.h"
#include <errno.h>
#include <syslog.h>
#include <unistd.h> /* for getuid(), exit(), getopt() */
#include <signal.h>
#include <sys/wait.h> /* for wait() */
#include <security/pam_appl.h> /* for PAM functions */
#include <security/pam_misc.h> /* for misc_conv PAM utility function */
#define SERVICE_NAME "pam_selinux_check" /* the name of this program for PAM */
/* The file containing the context to run
* the scripts under. */
int authenticate_via_pam( const char *user , pam_handle_t **pamh);
/* authenticate_via_pam()
*
* in: user
* out: nothing
* return: value condition
* ----- ---------
* 1 pam thinks that the user authenticated themselves properly
* 0 otherwise
*
* this function uses pam to authenticate the user running this
* program. this is the only function in this program that makes pam
* calls.
*
*/
int authenticate_via_pam( const char *user , pam_handle_t **pamh) {
struct pam_conv *conv;
int result = 0; /* our result, set to 0 (not authenticated) by default */
/* this is a jump table of functions for pam to use when it wants to *
* communicate with the user. we'll be using misc_conv(), which is *
* provided for us via pam_misc.h. */
struct pam_conv pam_conversation = {
misc_conv,
NULL
};
conv = &pam_conversation;
/* make `p_pam_handle' a valid pam handle so we can use it when *
* calling pam functions. */
if( PAM_SUCCESS != pam_start( SERVICE_NAME,
user,
conv,
pamh ) ) {
fprintf( stderr, _("failed to initialize PAM\n") );
exit( -1 );
}
if( PAM_SUCCESS != pam_set_item(*pamh, PAM_RUSER, user))
{
fprintf( stderr, _("failed to pam_set_item()\n") );
exit( -1 );
}
/* Ask PAM to authenticate the user running this program */
if( PAM_SUCCESS == pam_authenticate(*pamh,0) ) {
if ( PAM_SUCCESS == pam_open_session(*pamh, 0) )
result = 1; /* user authenticated OK! */
}
return( result );
} /* authenticate_via_pam() */
int
main (int argc, char **argv)
{
pam_handle_t *pamh;
int childPid;
if (argc < 1)
exit (-1);
if (!authenticate_via_pam(argv[1],&pamh))
exit(-1);
childPid = fork();
if (childPid < 0) {
/* error in fork() */
fprintf(stderr, _("login: failure forking: %m"));
pam_close_session(pamh, 0);
/* We're done with PAM. Free `pam_handle'. */
pam_end( pamh, PAM_SUCCESS );
exit(0);
}
if (childPid) {
close(0); close(1); close(2);
struct sigaction sa;
memset(&sa,0,sizeof(sa));
sa.sa_handler = SIG_IGN;
sigaction(SIGQUIT, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
while(wait(NULL) == -1 && errno == EINTR) /**/ ;
openlog("login", LOG_ODELAY, LOG_AUTHPRIV);
pam_close_session(pamh, 0);
/* We're done with PAM. Free `pam_handle'. */
pam_end( pamh, PAM_SUCCESS );
exit(0);
}
argv[0]=strdup ("/bin/sh");
argv[1]=NULL;
/* NOTE: The environment has not been sanitized. LD_PRELOAD and other fun
* things could be set. */
execv("/bin/sh",argv);
fprintf(stderr,"Failure\n");
return 0;
}
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