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/* vi: set sw=4 ts=4: */
/*
* Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
* All rights reserved.
*
* 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, this list of conditions and the following disclaimer.
* 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. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``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 JULIE HAUGH OR CONTRIBUTORS 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.
*/
#include "busybox.h"
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <ctype.h>
#include "pwd.h"
#include "grp.h"
#ifdef CONFIG_FEATURE_SHADOWPASSWDS
#include "shadow.h"
#endif
#define DEFAULT_LOGIN_PATH "/bin:/usr/bin"
#define DEFAULT_ROOT_LOGIN_PATH "/usr/sbin:/bin:/usr/bin:/sbin"
static void xsetenv ( const char *key, const char *value )
{
if ( setenv ( key, value, 1 ))
error_msg_and_die ( "out of memory" );
}
/* Become the user and group(s) specified by PW. */
void change_identity ( const struct passwd *pw )
{
if ( initgroups ( pw-> pw_name, pw-> pw_gid ) == -1 )
perror_msg_and_die ( "cannot set groups" );
endgrent ( );
if ( setgid ( pw-> pw_gid ))
perror_msg_and_die ( "cannot set group id" );
if ( setuid ( pw->pw_uid ))
perror_msg_and_die ( "cannot set user id" );
}
/* Run SHELL, or DEFAULT_SHELL if SHELL is empty.
If COMMAND is nonzero, pass it to the shell with the -c option.
If ADDITIONAL_ARGS is nonzero, pass it to the shell as more
arguments. */
void run_shell ( const char *shell, int loginshell, const char *command, const char **additional_args )
{
const char **args;
int argno = 1;
int additional_args_cnt = 0;
for ( args = additional_args; args && *args; args++ )
additional_args_cnt++;
if ( additional_args )
args = (const char **) xmalloc (sizeof (char *) * ( 4 + additional_args_cnt ));
else
args = (const char **) xmalloc (sizeof (char *) * 4 );
args [0] = get_last_path_component ( xstrdup ( shell ));
if ( loginshell ) {
char *args0 = xmalloc ( xstrlen ( args [0] ) + 2 );
args0 [0] = '-';
strcpy ( args0 + 1, args [0] );
args [0] = args0;
}
if ( command ) {
args [argno++] = "-c";
args [argno++] = command;
}
if ( additional_args ) {
for ( ; *additional_args; ++additional_args )
args [argno++] = *additional_args;
}
args [argno] = 0;
execv ( shell, (char **) args );
perror_msg_and_die ( "cannot run %s", shell );
}
/* Return 1 if SHELL is a restricted shell (one not returned by
getusershell), else 0, meaning it is a standard shell. */
int restricted_shell ( const char *shell )
{
char *line;
setusershell ( );
while (( line = getusershell ( ))) {
if (( *line != '#' ) && ( strcmp ( line, shell ) == 0 ))
break;
}
endusershell ( );
return line ? 0 : 1;
}
/* Update `environ' for the new shell based on PW, with SHELL being
the value for the SHELL environment variable. */
void setup_environment ( const char *shell, int loginshell, int changeenv, const struct passwd *pw )
{
if ( loginshell ) {
char *term;
/* Change the current working directory to be the home directory
* of the user. It is a fatal error for this process to be unable
* to change to that directory. There is no "default" home
* directory.
* Some systems default to HOME=/
*/
if ( chdir ( pw-> pw_dir )) {
if ( chdir ( "/" )) {
syslog ( LOG_WARNING, "unable to cd to %s' for user %s'\n", pw-> pw_dir, pw-> pw_name );
error_msg_and_die ( "cannot cd to home directory or /" );
}
fputs ( "warning: cannot change to home directory\n", stderr );
}
/* Leave TERM unchanged. Set HOME, SHELL, USER, LOGNAME, PATH.
Unset all other environment variables. */
term = getenv ("TERM");
clearenv ( );
if ( term )
xsetenv ( "TERM", term );
xsetenv ( "HOME", pw-> pw_dir );
xsetenv ( "SHELL", shell );
xsetenv ( "USER", pw-> pw_name );
xsetenv ( "LOGNAME", pw-> pw_name );
xsetenv ( "PATH", ( pw-> pw_uid ? DEFAULT_LOGIN_PATH : DEFAULT_ROOT_LOGIN_PATH ));
}
else if ( changeenv ) {
/* Set HOME, SHELL, and if not becoming a super-user,
USER and LOGNAME. */
xsetenv ( "HOME", pw-> pw_dir );
xsetenv ( "SHELL", shell );
if ( pw-> pw_uid ) {
xsetenv ( "USER", pw-> pw_name );
xsetenv ( "LOGNAME", pw-> pw_name );
}
}
}
/* Ask the user for a password.
Return 1 if the user gives the correct password for entry PW,
0 if not. Return 1 without asking for a password if run by UID 0
or if PW has an empty password. */
int correct_password ( const struct passwd *pw )
{
char *unencrypted, *encrypted, *correct;
#ifdef CONFIG_FEATURE_SHADOWPASSWDS
if (( strcmp ( pw-> pw_passwd, "x" ) == 0 ) || ( strcmp ( pw-> pw_passwd, "*" ) == 0 )) {
struct spwd *sp = getspnam ( pw-> pw_name );
if ( !sp )
error_msg_and_die ( "no valid shadow password" );
correct = sp-> sp_pwdp;
}
else
#endif
correct = pw-> pw_passwd;
if ( correct == 0 || correct[0] == '\0' )
return 1;
unencrypted = getpass ( "Password: " );
if ( !unencrypted )
{
fputs ( "getpass: cannot open /dev/tty\n", stderr );
return 0;
}
encrypted = crypt ( unencrypted, correct );
memset ( unencrypted, 0, xstrlen ( unencrypted ));
return ( strcmp ( encrypted, correct ) == 0 ) ? 1 : 0;
}
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