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sudo/sudo.c
Todd C. Miller 22c7d31a5f took out -l
1995-03-29 13:16:48 +00:00

773 lines
18 KiB
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/*
* CU sudo version 1.3.1 (based on Root Group sudo version 1.1)
*
* This software comes with no waranty whatsoever, use at your own risk.
*
* Please send bugs, changes, problems to sudo-bugs@cs.colorado.edu
*
*/
/*
* sudo version 1.1 allows users to execute commands as root
* Copyright (C) 1991 The Root Group, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 1, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
**************************************************************************
*
* sudo.c
*
* This is the main() routine for sudo
*
* sudo is a program to allow users to execute commands
* as root. The commands are defined in a global network-
* wide file and can be distributed.
*
* sudo has been hacked far and wide. Too many people to
* know about. It's about time to come up with a secure
* version that will work well in a network.
*
* This most recent version is done by:
*
* Jeff Nieusma <nieusma@rootgroup.com>
* Dave Hieb <davehieb@rootgroup.com>
*
* However, due to the fact that both of the above are no longer
* working at Root Group, I am maintaining the "CU version" of
* sudo.
* Todd Miller <millert@cs.colorado.edu>
*/
#ifndef lint
static char rcsid[] = "$Id$";
#endif /* lint */
#define MAIN
#include "config.h"
#include <stdio.h>
#ifdef STDC_HEADERS
#include <stdlib.h>
#endif /* STDC_HEADERS */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif /* HAVE_STRINGS_H */
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif /* HAVE_MALLOC_H */
#include <pwd.h>
#include <netdb.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#else
#include <sys/ioctl.h>
#endif /* HAVE_SYS_SOCKIO_H */
#ifdef _ISC
#include <sys/stream.h>
#include <sys/sioctl.h>
#include <sys/stropts.h>
#endif /* _ISC */
#ifdef _MIPS
#include <net/soioctl.h>
#endif /* _MIPS */
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <sys/param.h>
#if defined(__osf__) && defined(HAVE_C2_SECURITY)
#include <sys/security.h>
#include <prot.h>
#endif /* __osf__ && HAVE_C2_SECURITY */
#include "sudo.h"
#include "options.h"
#include "version.h"
#ifndef STDC_HEADERS
#ifndef __GNUC__ /* gcc has its own malloc */
extern char *malloc __P((size_t));
#endif /* __GNUC__ */
#ifdef HAVE_STRDUP
extern char *strdup __P((const char *));
#endif /* HAVE_STRDUP */
#endif /* STDC_HEADERS */
/*
* local functions not visible outside sudo.c
*/
static int parse_args __P((void));
static void usage __P((int));
static void load_globals __P((void));
static void check_sudoers __P((void));
static void load_interfaces __P((void));
static void load_cmnd __P((void));
static void add_env __P((void));
static void rmenv __P((char **, char *, int));
static void clean_env __P((char **));
/*
* Globals
*/
int Argc;
char **Argv;
char *cmnd = NULL;
char *user = NULL;
char *epasswd = NULL;
char host[MAXHOSTNAMELEN + 1];
struct interface *interfaces;
int num_interfaces;
char cwd[MAXPATHLEN + 1];
uid_t uid = (uid_t)-2;
/********************************************************************
*
* main ()
*
* the driving force behind sudo...
*/
main(argc, argv)
int argc;
char **argv;
{
int rtn;
int sudo_mode = MODE_RUN;
extern char ** environ;
#if defined(__osf__) && defined(HAVE_C2_SECURITY)
(void) set_auth_parameters();
#endif /* __osf__ && HAVE_C2_SECURITY */
Argv = argv;
Argc = argc;
/*
* parse our arguments
*/
sudo_mode = parse_args();
switch(sudo_mode) {
case MODE_VERSION :
case MODE_HELP :
(void) printf("CU Sudo version %s\n", version);
if (sudo_mode == MODE_VERSION)
exit(0);
else
usage(0);
break;
case MODE_VALIDATE :
cmnd = "validate";
break;
case MODE_LIST :
cmnd = "list";
break;
}
/*
* Close all file descriptors to make sure we have a nice
* clean slate from which to work.
*/
#ifdef HAVE_SYSCONF
for (rtn = sysconf(_SC_OPEN_MAX) - 1; rtn > 3; rtn--)
(void) close(rtn);
#else
for (rtn = getdtablesize() - 1; rtn > 3; rtn--)
(void) close(rtn);
#endif /* HAVE_SYSCONF */
check_sudoers(); /* check mode/owner on _PATH_SUDO_SUDOERS */
clean_env(environ); /* clean up the environment (no LD_*) */
load_globals(); /* load the user host cmnd and uid variables */
if (sudo_mode == MODE_RUN) {
load_cmnd(); /* load the cmnd global variable */
} else if (sudo_mode == MODE_KILL) {
remove_timestamp(); /* remove the timestamp ticket file */
exit(0);
} else if (sudo_mode == MODE_LIST) {
#ifdef notyet
(void) validate(); /* list the user's available commands */
#else
(void) fprintf(stderr,
"Sorry, the list command is not currently implemented.\n");
#endif
exit(0);
}
add_env(); /* add in SUDO_* envariables */
rtn = validate(); /* validate the user */
switch (rtn) {
case VALIDATE_OK:
check_user();
log_error(ALL_SYSTEMS_GO);
if (sudo_mode == MODE_VALIDATE)
exit(0);
set_perms(PERM_FULL_ROOT);
EXEC(cmnd, &Argv[1]);
perror(cmnd); /* exec failed! */
exit(-1);
break;
case VALIDATE_NO_USER:
case VALIDATE_NOT_OK:
case VALIDATE_ERROR:
default:
log_error(rtn);
set_perms(PERM_FULL_USER);
inform_user(rtn);
exit(1);
break;
}
}
/**********************************************************************
*
* load_globals()
*
* This function primes these important global variables:
* user, host, cwd, uid
*/
static void load_globals()
{
struct passwd *pw_ent;
struct hostent *h_ent;
char *p;
uid = getuid(); /* we need to tuck this away for safe keeping */
#ifdef HAVE_TZSET
(void) tzset(); /* set the timezone if applicable */
#endif /* HAVE_TZSET */
/*
* loading the user & epasswd global variable from the passwd file
* (must be done as root to get real passwd on some systems)
*/
if ((pw_ent = getpwuid(uid)) == NULL) {
(void) sprintf(user, "%u", uid);
log_error(GLOBAL_NO_PW_ENT);
inform_user(GLOBAL_NO_PW_ENT);
exit(1);
}
user = strdup(pw_ent -> pw_name);
epasswd = strdup(pw_ent -> pw_passwd);
if (user == NULL || epasswd == NULL) {
perror("malloc");
(void) fprintf(stderr, "%s: cannot allocate memory!\n", Argv[0]);
exit(1);
}
/*
* We only want to be root when we absolutely need it.
* This will effectively do setreuid(0, uid) but for portability...
*/
set_perms(PERM_ROOT);
set_perms(PERM_USER);
#ifdef UMASK
(void) umask((mode_t)UMASK);
#endif /* UMASK */
/*
* so we know where we are... (do as user)
*/
if (!getcwd(cwd, (size_t) sizeof(cwd))) {
(void) fprintf(stderr, "%s: Can't get working directory!\n", Argv[0]);
exit(1);
}
#ifdef NO_ROOT_SUDO
if (uid == 0) {
(void) fprintf(stderr, "You are already root, you don't need to use sudo.\n");
exit(1);
}
#endif
/*
* load the host global variable from gethostname()
* and use gethostbyname() if we want it to be fully qualified.
*/
if ((gethostname(host, MAXHOSTNAMELEN))) {
strcpy(host, "localhost");
log_error(GLOBAL_NO_HOSTNAME);
inform_user(GLOBAL_NO_HOSTNAME);
#ifdef FQDN
} else {
if ((h_ent = gethostbyname(host)) == NULL)
log_error(GLOBAL_HOST_UNREGISTERED);
else
strcpy(host, h_ent -> h_name);
}
#else
}
/*
* load a list of ip addresses and netmasks into
* the interfaces array.
*/
load_interfaces();
/*
* We don't want to return the fully quallified name unless FQDN is set
*/
if ((p = strchr(host, '.')))
*p = '\0';
#endif /* FQDN */
}
/**********************************************************************
*
* parse_args()
*
* this function parses the arguments to sudo
*/
static int parse_args()
{
int ret=MODE_RUN; /* what mode is suod to be run in? */
if (Argc < 2) /* no options and no command */
usage(1);
if (Argv[1][0] == '-') {
if (Argc > 2) /* only one -? option allowed */
usage(1);
if (Argv[1][1] != '\0' && Argv[1][2] != '\0') {
(void) fprintf(stderr, "%s: Please use single character options\n", Argv[0]);
usage(1);
}
switch (Argv[1][1]) {
case 'v':
ret = MODE_VALIDATE;
break;
case 'k':
ret = MODE_KILL;
break;
case 'l':
ret = MODE_LIST;
break;
case 'V':
ret = MODE_VERSION;
break;
case 'h':
ret = MODE_HELP;
break;
case '\0':
(void) fprintf(stderr, "%s: '-' requires an argument\n",
Argv[0]);
usage(1);
default:
(void) fprintf(stderr, "%s: Illegal option %s\n", Argv[0],
Argv[1]);
usage(1);
}
}
return(ret);
}
/**********************************************************************
*
* usage()
*
* this function just gives you instructions and exits
*/
static void usage(exit_val)
int exit_val;
{
(void) fprintf(stderr, "usage: %s -V | -h | -l | -v | -k | <command>\n", Argv[0]);
exit(exit_val);
}
/**********************************************************************
*
* clean_env()
*
* This function builds cleans up the environ pointer so that all execv*()'s
* omit LD_* variables and hard-code PATH if SECURE_PATH is defined.
*/
static void clean_env(envp)
char **envp;
{
/*
* omit all LD_* environmental vars
*/
rmenv(envp, "LD_", 3);
#ifdef __hpux
rmenv(envp, "SHLIB_PATH", 10);
#endif /* __hpux */
#ifdef _AIX
rmenv(envp, "LIBPATH", 7);
#endif /* _AIX */
#ifdef __alpha
rmenv(envp, "_RLD_", 5);
#endif /* __alpha */
/* set IFS to a sane default (same as sh(1) */
sudo_setenv("IFS", " \t\n");
#ifdef SECURE_PATH
sudo_setenv("PATH", SECURE_PATH);
#endif /* SECURE_PATH */
}
/**********************************************************************
*
* rmenv()
*
* this function removes things from the environment that match the
* string "s" up to length len [ie: with strncmp()].
*/
static void rmenv(envp, s, len)
char ** envp; /* pointer to environment */
char * s; /* string to search for */
int len; /* how much of it to check */
{
char ** tenvp; /* temp env pointer */
char ** move; /* used to move around */
/*
* cycle through the environment and purge strings that match s
*/
for (tenvp=envp; *tenvp; tenvp++) {
if (!strncmp(*tenvp, s, len)) {
/* matched: remove by shifting everything below one up */
for (move=tenvp; *move; move++)
*move = *(move+1);
tenvp--;
}
}
}
/**********************************************************************
*
* add_env()
*
* this function adds sudo-specific variables into the environment
*/
static void add_env()
{
char *uidstr;
int len;
uid_t n;
/* add the SUDO_USER envariable */
if (sudo_setenv("SUDO_USER", user)) {
perror("malloc");
(void) fprintf(stderr, "%s: cannot allocate memory!\n", Argv[0]);
exit(1);
}
/* add the SUDO_UID envariable */
for (len = 2, n = uid; (int) (n = n / 10) != 0; )
++len;
uidstr = (char *) malloc(len+1);
if (uidstr == NULL) {
perror("malloc");
(void) fprintf(stderr, "%s: cannot allocate memory!\n", Argv[0]);
exit(1);
}
(void) sprintf(uidstr, "%d", (int)uid);
if (sudo_setenv("SUDO_UID", uidstr)) {
perror("malloc");
(void) fprintf(stderr, "%s: cannot allocate memory!\n", Argv[0]);
exit(1);
}
(void) free(uidstr);
}
/**********************************************************************
*
* load_cmnd()
*
* This function sets the cmnd global variable based on Argv[1]
*/
static void load_cmnd()
{
if (strlen(Argv[1]) > MAXPATHLEN) {
errno = ENAMETOOLONG;
(void) fprintf(stderr, "%s: %s: Pathname too long\n", Argv[0], Argv[1]);
exit(1);
}
/*
* Resolve the path
*/
if ((cmnd = find_path(Argv[1])) == NULL) {
(void) fprintf(stderr, "%s: %s: command not found\n", Argv[0], Argv[1]);
exit(1);
}
}
/**********************************************************************
*
* load_interfaces()
*
* This function sets the interfaces global variable
* and sets the constituent ip addrs and netmasks.
*/
static void load_interfaces()
{
struct ifconf ifconf;
struct ifreq ifreq;
struct in_addr *inptr;
char buf[BUFSIZ];
int sock, len;
int i, j;
#ifdef _ISC
struct ifreq *ifrp;
struct strioctl strioctl;
#endif /* _ISC */
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
perror("socket");
exit(1);
}
/*
* get interface configuration or return (leaving interfaces NULL)
*/
ifconf.ifc_len = sizeof(buf);
ifconf.ifc_buf = buf;
#ifdef _ISC
strioctl.ic_cmd = SIOCGIFCONF;
strioctl.ic_dp = (char *)&ifconf;
strioctl.ic_len = sizeof(ifconf);
if (ioctl(sock, I_STR, &strioctl) < 0) {
/* networking probably not installed in kernel */
return;
}
#else
if (ioctl(sock, SIOCGIFCONF, (char *)(&ifconf)) < 0) {
/* networking probably not installed in kernel */
return;
}
#endif /* _ISC */
/*
* find out how many interfaces exist, skipping bogus ones.
*/
len = num_interfaces = ifconf.ifc_len / sizeof(struct ifreq);
for (i = 0; i < len; i++) {
inptr = &(((struct sockaddr_in *)&ifconf.ifc_req[i].ifr_addr)->sin_addr);
if (inptr->s_addr == inet_addr("127.0.0.1") ||
inptr->s_addr == inet_addr("255.255.255.255") ||
inptr->s_addr == inet_addr("0.0.0.0"))
--num_interfaces;
}
/*
* malloc() space for interfaces array
*/
interfaces = (struct interface *) malloc(sizeof(struct interface) *
num_interfaces);
if (interfaces == NULL) {
perror("malloc");
(void) fprintf(stderr, "%s: cannot allocate memory!\n", Argv[0]);
exit(1);
}
/*
* for each interface, get the ip address and netmask
*/
for (i = 0, j = 0; i < len; i++) {
inptr = &(((struct sockaddr_in *)&ifconf.ifc_req[i].ifr_addr)->sin_addr);
/* get the ip address */
if (inptr->s_addr == inet_addr("127.0.0.1") ||
inptr->s_addr == inet_addr("255.255.255.255") ||
inptr->s_addr == inet_addr("0.0.0.0"))
continue;
(void) memcpy(&interfaces[j].addr, inptr, sizeof(struct in_addr));
/* get the netmask */
#ifdef SIOCGIFNETMASK
(void) strcpy(ifreq.ifr_name, ifconf.ifc_req[i].ifr_name);
if (ioctl(sock, SIOCGIFNETMASK, (char *)(&ifreq)) >= 0) {
(void) memcpy(&interfaces[j].netmask,
&(((struct sockaddr_in *)&ifreq.ifr_addr)->sin_addr),
sizeof(struct in_addr));
} else {
#else
{
#endif /* SIOCGIFNETMASK */
if (IN_CLASSC(interfaces[j].addr.s_addr))
interfaces[j].netmask.s_addr = htonl(IN_CLASSC_NET);
else if (IN_CLASSB(interfaces[j].addr.s_addr))
interfaces[j].netmask.s_addr = htonl(IN_CLASSB_NET);
else
interfaces[j].netmask.s_addr = htonl(IN_CLASSA_NET);
}
++j;
}
}
/**********************************************************************
*
* check_sudoers()
*
* This function check to see that the sudoers file is owned by
* SUDOERS_OWNER and not writable by anyone else.
*/
static void check_sudoers()
{
struct stat statbuf;
struct passwd *pw_ent;
if (!(pw_ent = getpwnam(SUDOERS_OWNER))) {
(void) fprintf(stderr, "%s: no passwd entry for sudoers file owner (%s)\n", Argv[0], SUDOERS_OWNER);
exit(1);
}
if (lstat(_PATH_SUDO_SUDOERS, &statbuf)) {
(void) fprintf(stderr, "%s: Can't stat %s: ", Argv[0], _PATH_SUDO_SUDOERS);
perror("");
exit(1);
} else if (!S_ISREG(statbuf.st_mode)) {
(void) fprintf(stderr, "%s: %s is not a regular file!\n", Argv[0], _PATH_SUDO_SUDOERS);
exit(1);
} else if (statbuf.st_uid != pw_ent -> pw_uid) {
(void) fprintf(stderr, "%s: %s is not owned by %s!\n", Argv[0], _PATH_SUDO_SUDOERS, SUDOERS_OWNER);
exit(1);
} else if ((statbuf.st_mode & 0000066)) {
(void) fprintf(stderr, "%s: %s is readable or writeable by other than %s!\n", Argv[0], _PATH_SUDO_SUDOERS, SUDOERS_OWNER);
exit(1);
}
}
/**********************************************************************
*
* set_perms()
*
* this function sets real and effective uids and gids based on perm.
*/
void set_perms(perm)
int perm;
{
struct passwd *pw_ent;
switch(perm) {
case PERM_ROOT :
if (setuid(0)) {
perror("setuid(0)");
exit(1);
}
break;
case PERM_FULL_ROOT :
if (setuid(0)) {
perror("setuid(0)");
exit(1);
}
if (!(pw_ent = getpwuid(0))) {
perror("getpwuid(0)");
} else if (setgid(pw_ent->pw_gid)) {
perror("setgid");
}
break;
case PERM_USER :
if (seteuid(uid)) {
perror("seteuid(uid)");
exit(1);
}
break;
case PERM_FULL_USER :
if (setuid(0)) {
perror("setuid(0)");
exit(1);
}
if (setuid(uid)) {
perror("setuid(uid)");
exit(1);
}
break;
case PERM_SUDOERS :
if (setuid(0)) {
perror("setuid(0)");
exit(1);
}
if (!(pw_ent = getpwnam(SUDOERS_OWNER))) {
(void) fprintf(stderr, "%s: no passwd entry for sudoers file owner (%s)\n", Argv[0], SUDOERS_OWNER);
exit(1);
} else if (seteuid(pw_ent->pw_uid)) {
perror("seteuid");
}
break;
}
}
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