numlib/changeuidgid.c

   1 /*
   2 ** Copyright 1998 - 2002 Double Precision, Inc.  See COPYING for
   3 ** distribution information.
   4 */
   5
   6 #if     HAVE_CONFIG_H
   7 #include        "config.h"
   8 #endif
   9 #include        <sys/types.h>
  10 #if     HAVE_UNISTD_H
  11 #include        <unistd.h>
  12 #endif
  13 #include        <stdio.h>
  14 #include        <stdlib.h>
  15 #include        <string.h>
  16 #include        <grp.h>
  17 #include        <pwd.h>
  18 #include        <errno.h>
  19
  20 #include        "numlib.h"
  21
  22 static const char rcsid[]="$Id: changeuidgid.c,v 1.2 2003/01/05 04:01:17 mrsam Exp $";
  23
  24 void libmail_changegroup(gid_t gid)
  25 {
  26         if ( setgid(gid))
  27         {
  28                 perror("setgid");
  29                 exit(1);
  30         }
  31
  32 #if HAVE_SETGROUPS
  33         if ( getuid() == 0 && setgroups(1, &gid) )
  34         {
  35                 perror("setgroups");
  36                 exit(1);
  37         }
  38 #endif
  39 }
  40
  41 void libmail_changeuidgid(uid_t uid, gid_t gid)
  42 {
  43         libmail_changegroup(gid);
  44         if ( setuid(uid))
  45         {
  46                 perror("setuid");
  47                 exit(1);
  48         }
  49 }
  50
  51 void libmail_changeusername(const char *uname, const gid_t *forcegrp)
  52 {
  53 struct passwd *pw;
  54 uid_t   changeuid;
  55 gid_t   changegid;
  56
  57 /* uname might be a pointer returned from a previous called to getpw(),
  58 ** and libc has a problem getting it back.
  59 */
  60 char    *p=malloc(strlen(uname)+1);
  61
  62         if (!p)
  63         {
  64                 perror("malloc");
  65                 exit(1);
  66         }
  67         strcpy(p, uname);
  68
  69         errno=ENOENT;
  70         if ((pw=getpwnam(p)) == 0)
  71         {
  72                 free(p);
  73                 perror("getpwnam");
  74                 exit(1);
  75         }
  76         free(p);
  77
  78         changeuid=pw->pw_uid;
  79
  80         if ( !forcegrp )        forcegrp= &pw->pw_gid;
  81
  82         changegid= *forcegrp;
  83
  84         if ( setgid( changegid ))
  85         {
  86                 perror("setgid");
  87                 exit(1);
  88         }
  89
  90 #if HAVE_INITGROUPS
  91         if ( getuid() == 0 && initgroups(pw->pw_name, changegid) )
  92         {
  93                 perror("initgroups");
  94                 exit(1);
  95         }
  96 #else
  97 #if HAVE_SETGROUPS
  98         if ( getuid() == 0 && setgroups(1, &changegid) )
  99         {
 100                 perror("setgroups");
 101                 exit(1);
 102         }
 103 #endif
 104 #endif
 105
 106         if (setuid(changeuid))
 107         {
 108                 perror("setuid");
 109                 exit(1);
 110         }
 111 }