release/src/router/ppp/contrib/pppgetpass/pppgetpass.vt.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <errno.h>
   5 #include <unistd.h>
   6 #include <fcntl.h>
   7 #include <sys/stat.h>
   8 #include <sys/ioctl.h>
   9 #include <syslog.h>
  10 #include <termios.h>
  11 #include <sys/vt.h>
  12
  13 static int console_owner(uid_t, int);
  14
  15 int main(int argc, char **argv)
  16 {
  17   int console;
  18   uid_t uid;
  19   struct vt_stat origstate;
  20   int openvtnum;
  21   char openvtname[256];
  22   int openvt;
  23   gid_t gid;
  24   int chowned;
  25   FILE *fp;
  26   struct termios t;
  27   char pass[256], *nl;
  28   int outfd, passlen;
  29   ssize_t wrote;
  30   console=open("/dev/console", O_RDWR);
  31
  32   uid=getuid();
  33   gid=getgid();
  34   seteuid(uid);
  35
  36   openlog(argv[0], LOG_PID, LOG_DAEMON);
  37
  38   if(argc!=4) {
  39     syslog(LOG_WARNING, "Usage error");
  40     return 1;
  41   }
  42
  43   if(console<0) {
  44     syslog(LOG_ERR, "open(/dev/console): %m");
  45     return 1;
  46   }
  47
  48   if(ioctl(console, VT_GETSTATE, &origstate)<0) {
  49     syslog(LOG_ERR, "VT_GETSTATE: %m");
  50     return 1;
  51   }
  52
  53   if(uid) {
  54     if(!console_owner(uid, origstate.v_active)) {
  55       int i;
  56       for(i=0;i<64;++i) {
  57         if(i!=origstate.v_active && console_owner(uid, i))
  58           break;
  59       }
  60       if(i==64) {
  61         syslog(LOG_WARNING, "run by uid %lu not at console", (unsigned long)uid);
  62         return 1;
  63       }
  64     }
  65   }
  66
  67   if(ioctl(console, VT_OPENQRY, &openvtnum)<0) {
  68     syslog(LOG_ERR, "VT_OPENQRY: %m");
  69     return 1;
  70   }
  71   if(openvtnum==-1) {
  72     syslog(LOG_ERR, "No free VTs");
  73     return 1;
  74   }
  75
  76   snprintf(openvtname, sizeof openvtname, "/dev/tty%d", openvtnum);
  77   seteuid(0);
  78   openvt=open(openvtname, O_RDWR);
  79   if(openvt<0) {
  80     seteuid(uid);
  81     syslog(LOG_ERR, "open(%s): %m", openvtname);
  82     return 1;
  83   }
  84
  85   chowned=fchown(openvt, uid, gid);
  86   if(chowned<0) {
  87     seteuid(uid);
  88     syslog(LOG_ERR, "fchown(%s): %m", openvtname);
  89     return 1;
  90   }
  91
  92   close(console);
  93
  94   if(ioctl(openvt, VT_ACTIVATE, openvtnum)<0) {
  95     seteuid(uid);
  96     syslog(LOG_ERR, "VT_ACTIVATE(%d): %m", openvtnum);
  97     return 1;
  98   }
  99
 100   while(ioctl(openvt, VT_WAITACTIVE, openvtnum)<0) {
 101     if(errno!=EINTR) {
 102       ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 103       seteuid(uid);
 104       syslog(LOG_ERR, "VT_WAITACTIVE(%d): %m", openvtnum);
 105       return 1;
 106     }
 107   }
 108
 109   seteuid(uid);
 110   fp=fdopen(openvt, "r+");
 111   if(!fp) {
 112     seteuid(0);
 113     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 114     seteuid(uid);
 115     syslog(LOG_ERR, "fdopen(%s): %m", openvtname);
 116     return 1;
 117   }
 118
 119   if(tcgetattr(openvt, &t)<0) {
 120     seteuid(0);
 121     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 122     seteuid(uid);
 123     syslog(LOG_ERR, "tcgetattr(%s): %m", openvtname);
 124     return 1;
 125   }
 126   t.c_lflag &= ~ECHO;
 127   if(tcsetattr(openvt, TCSANOW, &t)<0) {
 128     seteuid(0);
 129     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 130     seteuid(uid);
 131     syslog(LOG_ERR, "tcsetattr(%s): %m", openvtname);
 132     return 1;
 133   }
 134
 135   if(fprintf(fp, "\033[2J\033[H")<0) {
 136     seteuid(0);
 137     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 138     seteuid(uid);
 139     syslog(LOG_ERR, "write error on %s: %m", openvtname);
 140     return 1;
 141   }
 142   if(argv[1][0] && argv[2][0]) {
 143     if(fprintf(fp, "Password for PPP client %s on server %s: ", argv[1], argv[2])<0) {
 144       seteuid(0);
 145       ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 146       seteuid(uid);
 147       syslog(LOG_ERR, "write error on %s: %m", openvtname);
 148       return 1;
 149     }
 150   } else if(argv[1][0] && !argv[2][0]) {
 151     if(fprintf(fp, "Password for PPP client %s: ", argv[1])<0) {
 152       syslog(LOG_ERR, "write error on %s: %m", openvtname);
 153       seteuid(0);
 154       ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 155       seteuid(uid);
 156       return 1;
 157     }
 158   } else if(!argv[1][0] && argv[2][0]) {
 159     if(fprintf(fp, "Password for PPP on server %s: ", argv[2])<0) {
 160       seteuid(0);
 161       ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 162       seteuid(uid);
 163       syslog(LOG_ERR, "write error on %s: %m", openvtname);
 164       return 1;
 165     }
 166   } else {
 167     if(fprintf(fp, "Enter PPP password: ")<0) {
 168       seteuid(0);
 169       ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 170       seteuid(uid);
 171       syslog(LOG_ERR, "write error on %s: %m", openvtname);
 172       return 1;
 173     }
 174   }
 175
 176   if(!fgets(pass, sizeof pass, fp)) {
 177     seteuid(0);
 178     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 179     seteuid(uid);
 180     if(ferror(fp)) {
 181       syslog(LOG_ERR, "read error on %s: %m", openvtname);
 182     }
 183     return 1;
 184   }
 185   if((nl=strchr(pass, '\n')))
 186     *nl=0;
 187   passlen=strlen(pass);
 188
 189   outfd=atoi(argv[3]);
 190   if((wrote=write(outfd, pass, passlen))!=passlen) {
 191     seteuid(0);
 192     ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 193     seteuid(uid);
 194     if(wrote<0)
 195       syslog(LOG_ERR, "write error on outpipe: %m");
 196     else
 197       syslog(LOG_ERR, "short write on outpipe");
 198     return 1;
 199   }
 200
 201   seteuid(0);
 202   ioctl(openvt, VT_ACTIVATE, origstate.v_active);
 203   seteuid(uid);
 204   return 0;
 205 }
 206
 207 static int console_owner(uid_t uid, int cons)
 208 {
 209   char name[256];
 210   struct stat st;
 211   snprintf(name, sizeof name, "/dev/tty%d", cons);
 212   if(stat(name, &st)<0) {
 213     if(errno!=ENOENT)
 214       syslog(LOG_ERR, "stat(%s): %m", name);
 215     return 0;
 216   }
 217   return uid==st.st_uid;
 218 }