v15i034: Run commands as another (or super) user
Rich Salz
rsalz at uunet.uu.net
Sat Jun 4 02:37:47 AEST 1988
Submitted-by: dirk <unido!altger!dirk>
Posting-number: Volume 15, Issue 34
Archive-name: surun
WHAT IT DOES:
Surun allows a user to run a command under root or another
user's privilege without typing the user's password. Permission
to use surun is given by a password file, usage is logged to
a logfile.
WHERE IT RUNS:
If use surun since 3/4 year under System V rel. 3.
If you plan to run it under BSD or XENIX just undefine the
TERMIO flag. If have not been testing surun under BSD or
XENIX for a long time now but it will run as well.
WHAT TO DO:
I am to lazy to correct my manual page, if someone who's native
language is english could to so pls. send it back to me.
cu,
Dirk Koeppen, DK-SOFT, West Germany
------------------------> CUT HERE <------------------------
: !/bin/sh
# To unbundle, sh(ell) this file
# ==============================
echo README 1>&2
cat >README <<'End of ===README==='
#ident @(#) README v1.2 of 88/10/03 , dirk
# This is Public-Domain. Military usage or resale forbidden.
# 6.Jun'87, dirk ( .. unido!cosa!dirk )
WHAT IT DOES:
Surun allows a user to run a command under root or another
user's privilege without typing the user's password. Permission
to use surun is given by a password file, usage is logged to
a logfile.
WHERE IT RUNS:
If use surun since 3/4 year under System V rel. 3.
If you plan to run it under BSD or XENIX just undefine the
TERMIO flag. If have not been testing surun under BSD or
XENIX for a long time now but it will run as well.
WHAT TO DO:
I am to lazy to correct my manual page, if someone who's native
language is english could to so pls. send it back to me.
cu,
dirk :-)
Dirk Koeppen, DK-SOFT, West Germany
End of ===README===
echo Makefile 1>&2
cat >Makefile <<'End of ===Makefile==='
#ident @(#) Makefile v1.2 of 88/10/03 , dirk
# Makefile for surun
# This is Public-Domain. Military usage or resale forbidden.
# 6.Jun'87, dirk ( .. unido!cosa!dirk )
SHELL =/bin/sh
CFLAGS =-O -s -DTERMIO
CLIBS =-lc_s
BINDIR =/usr/local/bin
MAN =nroff -man
MANDIR =/usr/man/u_man/man1
CATMANDIR =/usr/catman/u_man/man1
LOGFILE =/usr/adm/surun.log
ALLOWFILE =/usr/adm/surun.allow
SILENTCC =YES
surun: surun.c
cc $(CFLAGS) surun.c -o surun $(CLIBS)
# have to be root to install
install:
make surun
mv ./surun $(BINDIR)/surun
chown root $(BINDIR)/surun
chgrp bin $(BINDIR)/surun
chmod 4751 $(BINDIR)/surun
cp ./surun.1M $(MANDIR)/surun.1M
$(MAN) surun.1M > $(CATMANDIR)/surun.1M
pack -f $(CATMANDIR)/surun.1M
cp /dev/null $(LOGFILE)
chmod 640 $(LOGFILE)
echo "root::\nbin::" > $(ALLOWFILE)
chmod 640 $(ALLOWFILE)
clean:
rm -f foo Mout Lout a.out core *.i *.obj *.o
rm -f surun surun.allow surun.log surun.tmp
End of ===Makefile===
echo surun.c 1>&2
cat >surun.c <<'End of ===surun.c==='
char SCCS_id[]= "@(#) surun.c v2.2 of 88/10/03 , dirk";
/*
* SURUN
* run programs under root id
* usuage: surun [-] [-u username] [-p] .. command ..
*
* This is Public-Domain. Military usage or resale forbitten.
* 6.Jun'87, dirk ( .. unido!cosa!dirk )
*/
#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#include <pwd.h>
#include <time.h>
#include <string.h>
#include <signal.h>
#ifdef TERMIO
# include <termio.h>
#else
# include <sgtty.h>
#endif /* TERMIO */
#ifndef MAX_ARG
# define MAX_ARG 1024
#endif
#define ALLOWFILE "/usr/adm/surun.allow"
#define LOGFILE "/usr/adm/surun.log"
#define TEMPFILE "/usr/adm/surun.tmp"
#define ALLOWMASK 0640
#define CONSOLE "/dev/console"
#define SHELL "/bin/sh"
#define USAGE( str ) \
{ \
fprintf (stderr, "surun: %s\n", str ); \
fprintf (stderr, \
"usage: surun [-] [-u username] [-p] .. command ..\n"); \
exit (1); \
} \
#define ERROR( str ) \
{ \
fprintf (stderr, "surun: %s\n", str ); \
exit (1); \
} \
#define PERROR( str ) \
{ \
perror ( str ); \
exit (1); \
} \
struct passwd *getpwnam ();
char *crypt (), *getlogin (), *ttyname ();
long time ();
void exit ();
char log_string[64];
char env_shell[64]= "SHELL=";
char env_home[64]= "HOME=";
char env_logname[17]= "LOGNAME=";
char env_mail[64]= "MAIL=/usr/mail/";
char env_path1[128]= "PATH=:/bin:/usr/bin";
char env_path2[128]= "PATH=:/bin:/usr/bin:/etc";
char username[64];
char *userpasswd;
int userretry;
main(argc, argv)
char **argv;
{
char *user= "root" , *file,
*Argv[ MAX_ARG ], *environ[6];
int i, lflag= 0, pflag= 0;
long clock;
struct tm *date;
struct passwd *user_pwd;
/* check'n lookup args */
while ((**(++argv) == '-') && (*(*argv + 1) != '-'))
switch (*(*argv + 1))
{
case 'u' : user= *++argv;
if (!user)
USAGE( "no username" );
break;
case 'p' : pflag++; break;
case 'V' : printf ("%s\n", SCCS_id);
exit (0);
case NULL : lflag++; break;
default : USAGE( "not a valid option" );
}
if (!*argv && !pflag)
USAGE( "no command" );
/* create the time stamp */
clock= time ((long *)0);
date= gmtime (&clock);
sprintf (log_string, "SURUN %02d/%02d %02d:%02d + %s %s-%s",
date->tm_mday, date->tm_mon + 1, date->tm_hour, date->tm_min,
(strrchr (ttyname (0), '/') + 1), getlogin (), user);
/* do we have an valid entry in the allowfile ? */
if (!check_permission(getlogin ()) || !userretry)
{
*strchr (log_string, '+')= '-';
log(argv);
if (userretry)
ERROR( "no permission" )
else
ERROR( "number of password-retries exeeded" )
}
/* log it and change id*/
log(argv);
if (pflag)
{
setpasswd();
if (!*argv)
exit (0);
}
if ((user_pwd= getpwnam (user)) == NULL)
ERROR( "invalid username" );
if (setgid (user_pwd->pw_gid))
PERROR( user_pwd->pw_gid );
if (setuid (user_pwd->pw_uid))
PERROR( user_pwd->pw_uid );
/* execute it */
if (lflag)
{
file= user_pwd->pw_shell;
if (!*file)
file= SHELL;
environ[0]= strcat (env_shell, file);
environ[1]= strcat (env_home, user_pwd->pw_dir);
environ[2]= strcat (env_logname, user_pwd->pw_name);
environ[3]= strcat (env_mail, user_pwd->pw_name);
if (user_pwd->pw_uid)
environ[4]= env_path1;
else
environ[4]= env_path2;
environ[5]= NULL;
i= 0;
/* Argv[i++]= strrchr (file, '/') + 1; */
Argv[i++]= "-";
Argv[i++]= "-c";
while (Argv[i++]= *(argv++));
if (chdir (user_pwd->pw_dir) == -1)
PERROR( user_pwd->pw_dir );
if (execve (file, Argv, environ))
PERROR( file );
}
else
{
file= *argv;
if (execvp (file, argv))
PERROR( file );
}
/* unreached */
exit (0);
}
/*
* CHECK_PERMISSION
* check if the user has permissions and left retries to execute surun
*/
int
check_permission(lognam)
char *lognam;
{
FILE *allowfile;
char passwd[3];
int ok_flag= 0;
if (!(allowfile= fopen (ALLOWFILE, "r")))
ERROR( "cannot open the allow file" );
while (fgets (username, 64, allowfile) && !ok_flag)
{
if (isdigit (*(strrchr (username, ':') + 1)))
userretry= atoi (strrchr (username, ':') + 1);
else
userretry= 1;
userpasswd= strchr (username, ':') + 1;
*strrchr (username, ':')= NULL;
*(userpasswd - 1)= NULL;
if (!strcmp (username, lognam))
if (*userpasswd && userretry)
{
printf ("passwd: ");
raw(1);
passwd[0]= getchar ();
passwd[1]= getchar ();
raw(0);
passwd[2]= 0;
putchar ('\n');
if (!strcmp (crypt (passwd, userpasswd),
userpasswd))
ok_flag++;
else
{
userretry--;
fclose (allowfile);
update();
return (ok_flag);
}
}
else
ok_flag++;
}
fclose (allowfile);
return (ok_flag);
}
/*
* LOG
* log to console and logfile
*/
log(cmd)
char **cmd;
{
FILE *logfile, *console;
if (!(logfile= fopen (LOGFILE, "a+")))
ERROR( "cannot open the logfile" );
if (console= fopen (CONSOLE , "w"))
{
fprintf (console, "%s\n", log_string);
fclose (console);
}
fprintf (logfile, "%s :", log_string);
while (*cmd)
fprintf (logfile, " %s", *(cmd++));
fprintf (logfile, "\n");
fclose (logfile);
}
/*
* RAW
* 1: set terminal to raw mode and no echo
* 0: reset old terminal status
*/
raw(mode)
int mode;
{
#ifdef TERMIO
static struct termio t_save;
struct termio t;
if (mode)
{
ioctl (2, TCGETA, &t);
t_save= t;
t.c_lflag&= ~(ICANON|ECHO);
t.c_cc[VMIN]= 1;
t.c_cc[VTIME]= 0;
}
else
t= t_save;
ioctl (2, TCSETAW, &t);
#else
static struct sgttyb t_save;
struct sgttyb t;
if (mode)
{
ioctl (2, TIOCGETP, &t);
t_save= t;
t.sg_flags|= CBREAK;
t.sg_flags&= ~ECHO;
}
else
t= t_save;
ioctl (2, TIOCSETN, &t);
#endif /* TERMIO */
}
/*
* SETPASSWD
* get a new passwd and crypt it
*/
setpasswd()
{
long salt;
char salt_c[2], passwd[3];
int i;
printf ("New Password: ");
raw(1);
passwd[0]= getchar ();
passwd[1]= getchar ();
raw(0);
passwd[2]= 0;
putchar ('\n');
userretry= 0;
while ((userretry < 1) || (userretry > 9))
{
printf ("Number of retries (1-9): ");
scanf ("%d", &userretry);
}
time (&salt);
salt*= getpid ();
salt_c[0]= salt & 0x3f;
salt_c[1]= salt>>6 & 0x3f;
for (i= 0; i < 2; i++)
{
salt_c[i]+= '.';
if (salt_c[i] > '9')
salt_c[i]+= 'A' - ':';
if (salt_c[i] > 'Z')
salt_c[i]+= 'a' - '[';
}
userpasswd= crypt (passwd, salt_c);
update();
}
/*
* UPDATE
* update the surun.allow file with the current user data
*/
update()
{
FILE *in, *out;
char line[64];
if (!(in= fopen (ALLOWFILE, "r")))
ERROR( "cannot open allowfile" )
if (!(out= fopen (TEMPFILE, "w")))
ERROR( "cannot open tempfile" )
while (fgets (line, 64, in))
{
if (!strcmp (strtok (line, ":"), username))
fprintf (out, "%s:%s:%d\n", username,
userpasswd, userretry);
else
{
*(line+strlen (line))= ':';
fputs (line, out);
}
}
fclose (in);
fclose (out);
chmod (TEMPFILE, ALLOWMASK);
signal (SIGHUP, SIG_IGN);
signal (SIGINT, SIG_IGN);
signal (SIGQUIT, SIG_IGN);
#ifdef SIGSTP
signal (SIGSTP, SIG_IGN);
#endif /* SIGSTP */
unlink (ALLOWFILE);
if (link (TEMPFILE, ALLOWFILE))
ERROR( "cannot link tempfile to allowfile" );
unlink (TEMPFILE);
signal (SIGHUP, SIG_DFL);
signal (SIGINT, SIG_DFL);
signal (SIGQUIT, SIG_DFL);
#ifdef SIGSTP
signal (SIGSTP, SIG_DFL);
#endif /* SIGSTP */
}
End of ===surun.c===
echo surun.1M 1>&2
cat >surun.1M <<'End of ===surun.1M==='
.\" @(#) surun.1M.sh v1.2 of 88/10/03 , dirk
.TH SURUN 1M
.SH NAME
surun - run a command under root or another user's privilege
.SH SYNOPSIS
surun [-] [-u username] [-p] .. command ..
.SH OPTIONS
.sp
- login as the specified user
.sp
-u username set the userid to the one of user 'username'
.sp
-p set password and retry-counter
.sp
command commands to be executed
.SH DESCRIPTION
\fISurun\fR allows one to run a program under root or another
user's privilege without logging off or typing the user's
password. The default username is root (i.e., superuser).
For security reasons the user can set a short password of 2 characters
as well.
.PP
To use \fIsurun\fR, the user must have permission to execute the
\fIsurun\fR command. This is provided by an entry of the user's logname in the
\fI/usr/adm/surun.allow\fR file. If the user has this permission,
\fIsurun\fR executes the command or a new shell with the
\fIreal\fR user and group ID set to that of the specified user.
For security reasons the user has the possibility to setup a \fIpassword\fR
with a length of 2 characters. If a \fIpassword\fI is set, \fIsurun\fR prompts
for it first, this is done in 'cbreak/ no echo mode' so that the user does not
need to press <RETURN> or <EOF>. A misstyped password causes \fIsurun\fR to
decrement a counter in the \fI/usr/adm/surun.allow\fR file. If this counter
reaches 0, \fIsurun\fR aborts every time it is called. The super-user must
reset the counter to activate \fIsurun\fR for the misstyping user again.
.sp
The normal user ID is restored just after the \fIsurun\fR
command quits. Any additional arguments given on the command
line are passed to the program invoked by surun.
.PP
If the first argument to \fIsurun\fR is a -, the environment is changed
to what would be expected if the user actually logged in as the
specified user. This is done by invoking the program used as the
shell with an arg0 value whose first character is -, thus
causing first the system profile (/etc/profile, /etc/cshrc ) and then the
specified user profile (.profile, .cshrc, .login in the new users $HOME
directory) to be executed. Otherwise, the environment is passed along
with the possible exception of $PATH, which is set to /bin:/usr/
bin:/etc for root.
.PP
All attempts to execute a command via \fIsurun\fR are logged in the
logfile \fI/usr/adm/surun.log\fR and the device \fI/dev/console\fR.
The user's logname has to be an entry in the \fI/usr/adm/surun.allow\fR
file otherwise surun will not execute.
.SH FILE FORMAT
\fI/usr/adm/surun.log\fR:
.in +4
.nf
.sp
SURUN 28/01 22:27 + vt01 dirk-root : ls
| | | | | | |
date --+ | | | | | +-- command executed
time ---------+ | | | +--------- setuid to username
valid (+) ------+ | +-------------- username
invalid (-) |
ttyname -------------+
.sp
.fi
.in
\fI/usr/adm/surun.log\fR:
.in +4
.nf
.sp
dirk:IX2.swq4zvjvU:2
| | |
| | +-- number of left retries for password
| +----------- crypted password
+-------------------- users logname
.sp
.fi
A missing password disables the password check only if the number of left
retries is NULL (e.g. dirk::) or not 0 (e.g. dirk::1).
.sp
A missing retry-number is interpreted as 1 if there is no password set
.PP
.SH EXAMPLES
To execute the command 'ls /usr/adm' under the user 'bin' its
privileges while retaining your previously exported environment,
execute:
.PP
.in +12
surun -u bin ls /usr/adm
.PP
To execute the same command but change the environment to what would
be expected if 'bin' had originally logged in, execute:
.PP
.in +12
surun - -u bin ls /usr/adm
.PP
To set a password, execute:
.PP
.in +12
surun -p
.SH FILES
.nf
/etc/passwd system password file
/usr/adm/surun.log log file
/usr/adm/surun.allow list of users allowed to execute surun
/usr/adm/surun.tmp temporary file for updating the surun.allow file
.if
.PP
.SH SEE ALSO
su(1M), env(1), login(1), sh(1) \fIin the User's Reference Manual. \fR
passwd(4), profile(4), environ(5) \fIin the Programmer's Reference Manual.\fR
.SH CAVEATS
Since the sh(1) which calls surun is doing the wildcarding, be aware of
wildcards to directories which are not readable by you. Pass these wildcards
using quotes.
.sp
Example:
.in +4
/usr/lib is not readable for you.
.br
entering 'surun vi /usr/lib/uucp/L.*' will result in '/usr/lib/uucp' and not
in '/usr/lib/uucp/L.sys' due /usr/lib/uucp is not readable by you. Use the
command 'surun vi "/usr/lib/uucp/L.*"' instead.
.in -4
.SH AUTHOR
Dirk Koeppen, DK-SOFT, West Germany, .. unido!cosa!dirk
End of ===surun.1M===
exit 0
--
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