V10/cmd/passwdx.c
/*
* enter a password in the password file
* this program should be suid with owner
* with an owner with write permission on /etc/passwd
*/
#include <stdio.h>
#include <signal.h>
#include <pwd.h>
#include <errno.h>
#include <ctype.h>
#include <libc.h>
char passwd[] = "/etc/passwd";
char npasswd[] = "/etc/npasswd";
char tpasswd[] = "/etc/pwXXXXXX";
char stdprof[] = "/etc/stdprofile";
int newmode = 0755;
char *stdgroup = "unknown";
char *group;
int flags;
char *tempfile;
struct passwd *pwd;
long time();
char *mktemp();
char *readpasswd();
struct passwd *getpwent();
int endpwent();
char *strcpy();
char *crypt();
char *getpass();
char *getlogin();
extern int optind;
extern int errno;
int newuser;
int alter;
char *username;
struct passwd pw;
char *getstring();
char *newstr();
int rootid = 0;
main(argc, argv)
char *argv[];
{
char *pwp;
int c, u, maxuid;
FILE *tf;
while ((c = getopt(argc, argv, "na")) != EOF) {
switch(c) {
case 'n':
newuser++;
break;
case 'a':
alter++;
break;
default:
exit(1);
}
}
if (optind >= argc) {
if (newuser==0) {
if ((username = getlogin()) == NULL) {
printf ("Usage: passwd [-na] [user]\n");
exit(1);
} else
printf("Changing password for %s\n", username);
}
} else
username = argv[optind];
if (username==NULL) {
username = getstring("User: ");
if (username==NULL || *username=='\0') {
printf("Cannot default user\n");
exit(1);
}
}
maxuid = -1;
while ((pwd = getpwent()) != NULL) {
if (strcmp(pwd->pw_name, username) == 0) {
pw.pw_name = username;
pw.pw_passwd = newstr(pwd->pw_passwd);
pw.pw_uid = pwd->pw_uid;
pw.pw_gid = pwd->pw_gid;
pw.pw_gecos = newstr(pwd->pw_gecos);
pw.pw_dir = newstr(pwd->pw_dir);
pw.pw_shell = newstr(pwd->pw_shell);
}
if (pwd->pw_uid > maxuid)
maxuid = pwd->pw_uid;
}
endpwent();
if (pw.pw_name==NULL && newuser==0) {
printf("Cannot find password entry for %s\n", username);
exit(1);
}
if (newuser) {
if (pw.pw_name) {
printf("user %s already exists\n", username);
exit(1);
}
pw.pw_name = username;
}
u = getuid();
if (u!=rootid && (newuser || pw.pw_uid!=u)) {
printf("Permission denied.\n");
exit(1);
}
pwp = readpasswd(u, pw.pw_passwd);
if (pwp==NULL) {
if (newuser==0) {
printf("Password unchanged.\n");
if (alter==0)
exit(0);
pwp = pw.pw_passwd;
} else
pwp = "";
}
pw.pw_passwd = pwp;
if (alter!=0 || newuser!=0)
otherfields(maxuid+1, u);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
tempfile = mktemp(tpasswd);
if((tf=fopen(tempfile,"w")) == NULL) {
printf("Cannot create temporary file\n");
exit(1);
}
chmod(tempfile, 0644);
while((pwd=getpwent()) != NULL) {
if(strcmp(pwd->pw_name,username) == 0)
pwd = &pw;
fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n",
pwd->pw_name,
pwd->pw_passwd,
pwd->pw_uid,
pwd->pw_gid,
pwd->pw_gecos,
pwd->pw_dir,
pwd->pw_shell);
}
endpwent();
if (newuser) {
pwd = &pw;
fprintf(tf,"%s:%s:%d:%d:%s:%s:%s\n",
pwd->pw_name,
pwd->pw_passwd,
pwd->pw_uid,
pwd->pw_gid,
pwd->pw_gecos,
pwd->pw_dir,
pwd->pw_shell);
}
fclose(tf);
/*
* move temp back to passwd file
* (carefully)
*/
while (link(tempfile, npasswd) < 0) {
if (errno == EEXIST) {
if (*getstring("Password file busy... shall I wait?") == 'y')
sleep(5);
else
exit(1);
} else {
printf("Cannot link to temp\n");
exit(1);
}
}
if (unlink(passwd) < 0) {
printf("Cannot unlink old passwd\n");
exit(1);
}
if (link(npasswd, passwd) < 0) {
printf("Cannot link in new passwd.\n");
exit(1);
}
unlink(npasswd);
unlink(tempfile);
return 0;
}
char *
readpasswd(uid, opass)
char *opass;
{
static char minlen[] =
{ 8, 8, 6, 5, 6, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4};
register char *p, *npass;
register c, flags;
int ok, tries, pwlen;
long salt;
char saltc[2];
char *rev(), *multi();
register i;
if (uid!=0 && opass && *opass) {
npass = getpass("Old password:");
if (strcmp(crypt(npass, opass), opass)) {
printf("Sorry.\n");
exit(1);
}
}
opass = NULL;
for (ok=0, tries=0;;) {
if (ok==0 && tries) {
printf("Password too simple. Try again.\n");
opass = 0;
}
npass = newstr(getpass(ok?"Reconfirm password:":"New password:"));
if (opass && strcmp(opass, npass)) {
printf("Password mismatch.\n");
exit(1);
}
if (strcmp(npass, "sorry")==0 && tries==0) {
if (*getstring("You want an unusable password, right? ") == 'y')
return("sorry");
}
if (ok)
break;
pwlen = strlen(npass);
if (pwlen == 0)
return(NULL);
flags = 0;
p = npass;
while (c = *p++) {
if (islower(c))
flags |= 02;
else if (isupper(c))
flags |= 04;
else if (isdigit(c))
flags |= 01;
else
flags |= 010;
}
if (tries>2 || pwlen>=minlen[flags])
ok++;
tries++;
if((strcmp(npass, pw.pw_name) == 0)
|| (strcmp(npass, rev(pw.pw_name)) == 0)
|| (strcmp(npass, multi(pw.pw_name)) == 0)){
ok = 0;
tries = 1;
}
opass = npass;
}
time(&salt);
salt += getpid();
saltc[0] = salt & 077;
saltc[1] = (salt>>6) & 077;
for(i=0; i<2; i++) {
c = saltc[i] + '.';
if(c>'9') c += 7;
if(c>'Z') c += 6;
saltc[i] = c;
}
return(newstr(crypt(npass, saltc)));
}
char *
getstring(mesg, arg)
char *mesg, *arg;
{
char buf[128], *fgets();
printf(mesg, arg);
if (fgets(buf, 128, stdin) == NULL)
exit(1);
buf[strlen(buf)-1] = '\0';
return(newstr(buf));
}
char *
newstr(s)
char *s;
{
char *strcpy();
return(strcpy(malloc(strlen(s)+1), s));
}
otherfields(uid, myuid)
{
char *s;
int id;
if (newuser) {
s = getstring("UID: ");
while (!isnum(s)) {
printf ("Not numeric\n");
s = getstring ("Enter numeric user ID: ");
}
if (*s != '\0')
uid = atoi (s);
pw.pw_uid = uid;
pw.pw_gid = 1;
}
if (newuser || alter) {
char defdir[128];
strcpy (defdir, "/usr/");
strcat (defdir, pw.pw_name);
s = getstring("GCOS acct,box: ");
if (*s)
pw.pw_gecos = s;
if (pw.pw_gecos==NULL)
pw.pw_gecos = "";
s = getstring("Directory: ");
if (*s)
pw.pw_dir = s;
if (pw.pw_dir==NULL)
pw.pw_dir = newstr(defdir);
if (newuser) {
char *realdir;
realdir = pw.pw_dir;
if (realdir[0] == '*') {
realdir++;
if (realdir[0] != '/') {
char x[256];
strcpy (x, "/");
strcat (x, realdir);
strcat (x, "/");
strcat (x, pw.pw_name);
realdir = newstr (x);
}
pw.pw_dir = newstr(defdir);
symlink (realdir, defdir);
}
mkdir(realdir, newmode);
chown(realdir, pw.pw_uid, pw.pw_gid);
}
s = getstring("Shell: ");
if (*s)
pw.pw_shell = s;
if (pw.pw_shell == NULL)
pw.pw_shell = "";
/* Create .profile for the new user */
if (newuser) {
FILE *inf, *outf;
for (;;) {
s = getstring("Profile: ");
if (*s == '\0')
s = stdprof;
inf = fopen (s, "r");
if (inf != NULL || s == stdprof)
break;
printf ("Can't open %s\n", s);
}
if (inf != NULL) {
char pname[128];
register int c;
(void) strcpy (pname, pw.pw_dir);
(void) strcat (pname, "/.profile");
outf = fopen (pname, "w");
if (outf == NULL) {
printf ("can't create %s\n", pname);
exit(1);
}
(void) chown (pname, pw.pw_uid, pw.pw_gid);
(void) chmod (pname, newmode);
/*
* copy the profile file to the new
* user's .profile, transforming \N into
* the user's name, \D into his home
* directory, and \\ into \.
*/
while ((c = getc (inf)) != EOF) {
if (c == '\\') {
c = getc (inf);
switch (c) {
case 'D':
fputs (pw.pw_dir, outf);
break;
case 'N':
fputs (pw.pw_name,outf);
break;
case EOF:
break;
default:
putc ('\\', outf);
/* No break */
case '\\':
putc (c, outf);
break;
}
} else
putc (c, outf);
}
if (ferror (inf) || ferror (outf))
printf ("I/O error copying %s to %s\n",
s, pname);
(void) fclose (inf);
(void) fclose (outf);
}
}
}
}
int
isnum(s)
register char *s;
{
while (*s)
if (!isdigit(*s++))
return 0;
return 1;
}
char *rev(s)
char *s;
{
static char t[200];
char *p, *q;
p = s;
q = &t[199];
*q-- = '\0';
while(*q-- = *p++);
return q+2;
}
char *multi(s)
char *s;
{
int i, x;
char *p=s;
static char w[9];
while(*p++); x = p-s-1;
if(x > 4) return "password";
*w = '\0';
for(i=0;i<2*x*x-(x*x*x+47*x)/6+12;i++)
strcat(w,s);
return w;
}