2.9BSD - /usr/src/cmd/passwd.c

   1: /*
   2:  * enter a password in the password file
   3:  * this program should be suid with owner
   4:  * with an owner with write permission on /etc/passwd
   5:  */
   6: #include <stdio.h>
   7: #include <signal.h>
   8: #include <pwd.h>
   9: 
  10: char    passwd[] = "/etc/passwd";
  11: char    temp[]   = "/etc/ptmp";
  12: struct  passwd *pwd;
  13: struct  passwd *getpwent();
  14: int endpwent();
  15: char    *strcpy();
  16: char    *crypt();
  17: char    *getpass();
  18: char    *getlogin();
  19: char    *pw;
  20: char    pwbuf[10];
  21: char    buf[512];
  22: 
  23: main(argc, argv)
  24: char *argv[];
  25: {
  26:     char *p;
  27:     int i;
  28:     char saltc[2];
  29:     long salt;
  30:     int u,fi,fo;
  31: #ifdef  UCB_GRPMAST
  32:     int g;
  33: #endif
  34:     int insist;
  35:     int ok, flags;
  36:     int c;
  37:     int pwlen;
  38:     FILE *tf;
  39:     char *uname;
  40: 
  41:     insist = 0;
  42:     if(argc < 2) {
  43:         if ((uname = getlogin()) == NULL) {
  44:             printf ("Usage: passwd user\n");
  45:             goto bex;
  46:         } else {
  47:             printf("Changing password for %s\n", uname);
  48:         }
  49:     } else {
  50:         uname = argv[1];
  51:     }
  52:     while(((pwd=getpwent()) != NULL)&&(strcmp(pwd->pw_name,uname)!=0));
  53:     u = getuid();
  54: #ifdef  UCB_GRPMAST
  55:     g = getgid();
  56: #endif
  57:     if (    (pwd == NULL)
  58:          || ((u != 0)
  59:          && (u != pwd -> pw_uid)
  60: #ifdef  UCB_GRPMAST
  61:          && ((u != g) || (g != pwd -> pw_gid) || (pwd ->pw_uid == 0))
  62: #endif
  63:         )
  64:        )
  65:         {
  66:         printf("Permission denied.\n");
  67:         goto bex;
  68:         }
  69:     endpwent();
  70:     if (pwd->pw_passwd[0] && u != 0) {
  71:         strcpy(pwbuf, getpass("Old password:"));
  72:         pw = crypt(pwbuf, pwd->pw_passwd);
  73:         if(strcmp(pw, pwd->pw_passwd) != 0) {
  74:             printf("Sorry.\n");
  75:             goto bex;
  76:         }
  77:     }
  78: tryagn:
  79:     strcpy(pwbuf, getpass("New password:"));
  80:     pwlen = strlen(pwbuf);
  81:     if (pwlen == 0) {
  82:         printf("Password unchanged.\n");
  83:         goto bex;
  84:     }
  85:     ok = 0;
  86:     flags = 0;
  87:     p = pwbuf;
  88:     while(c = *p++){
  89:         if(c>='a' && c<='z') flags |= 2;
  90:         else if(c>='A' && c<='Z') flags |= 4;
  91:         else if(c>='0' && c<='9') flags |= 1;
  92:         else flags |= 8;
  93:     }
  94:     if(flags >=7 && pwlen>= 4) ok = 1;
  95:     if(((flags==2)||(flags==4)) && pwlen>=6) ok = 1;
  96:     if(((flags==3)||(flags==5)||(flags==6))&&pwlen>=5) ok = 1;
  97: 
  98:     if((ok==0) && (insist<2)){
  99:         if(flags==1)
 100:         printf("Please use at least one non-numeric character.\n");
 101:         else
 102:         printf("Please use a longer password.\n");
 103:         insist++;
 104:         goto tryagn;
 105:         }
 106: 
 107:     if (strcmp(pwbuf,getpass("Retype new password:")) != 0) {
 108:         printf ("Mismatch - password unchanged.\n");
 109:         goto bex;
 110:     }
 111: 
 112:     time(&salt);
 113:     salt += getpid();
 114: 
 115:     saltc[0] = salt & 077;
 116:     saltc[1] = (salt>>6) & 077;
 117:     for(i=0;i<2;i++){
 118:         c = saltc[i] + '.';
 119:         if(c>'9') c += 7;
 120:         if(c>'Z') c += 6;
 121:         saltc[i] = c;
 122:     }
 123:     pw = crypt(pwbuf, saltc);
 124:     signal(SIGHUP, SIG_IGN);
 125:     signal(SIGINT, SIG_IGN);
 126:     signal(SIGQUIT, SIG_IGN);
 127: 
 128:     if(access(temp, 0) >= 0) {
 129:         printf("Temporary file busy -- try again\n");
 130:         goto bex;
 131:     }
 132:     close(creat(temp,0600));
 133:     if((tf=fopen(temp,"w")) == NULL) {
 134:         printf("Cannot create temporary file\n");
 135:         goto bex;
 136:     }
 137: 
 138: /*
 139:  *	copy passwd to temp, replacing matching lines
 140:  *	with new password.
 141:  */
 142: 
 143:     while((pwd=getpwent()) != NULL) {
 144:         if(strcmp(pwd->pw_name,uname) == 0) {
 145:             u = getuid();
 146:             if (    (u != 0)
 147:                  && (u != pwd -> pw_uid)
 148: #ifdef  UCB_GRPMAST
 149:                  && ((u != g) || (g != pwd -> pw_gid) || (pwd ->pw_uid == 0))
 150: #endif
 151:                 )
 152:                 {
 153:                 printf("Permission denied.\n");
 154:                 goto out;
 155:             }
 156:             pwd->pw_passwd = pw;
 157:         }
 158:         fprintf(tf,"%s:%s:%u:%u:%s:%s:%s\n",
 159:             pwd->pw_name,
 160:             pwd->pw_passwd,
 161:             pwd->pw_uid,
 162:             pwd->pw_gid,
 163:             pwd->pw_gecos,
 164:             pwd->pw_dir,
 165:             pwd->pw_shell);
 166:     }
 167:     endpwent();
 168:     fclose(tf);
 169: 
 170: /*
 171:  *	copy temp back to passwd file
 172:  */
 173: 
 174:     if((fi=open(temp,0)) < 0) {
 175:         printf("Temp file disappeared!\n");
 176:         goto out;
 177:     }
 178:     if((fo=creat(passwd, 0644)) < 0) {
 179:         printf("Cannot recreat passwd file.\n");
 180:         goto out;
 181:     }
 182:     while((u=read(fi,buf,sizeof(buf))) > 0) write(fo,buf,u);
 183: 
 184: out:
 185:     unlink(temp);
 186: 
 187: bex:
 188:     exit(1);
 189: }

Defined functions

Defined variables