external/ibm-public/postfix/dist/src/util/set_ugid.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      set_ugid 3
   6 /* SUMMARY
   7 /*      set real, effective and saved user and group attributes
   8 /* SYNOPSIS
   9 /*      #include <set_ugid.h>
  10 /*
  11 /*      void    set_ugid(uid, gid)
  12 /*      uid_t   uid;
  13 /*      gid_t   gid;
  14 /* DESCRIPTION
  15 /*      set_ugid() sets the real, effective and saved user and group process
  16 /*      attributes and updates the process group access list to be just the
  17 /*      user's primary group. This operation is irreversible.
  18 /* DIAGNOSTICS
  19 /*      All system call errors are fatal.
  20 /* SEE ALSO
  21 /*      setuid(2), setgid(2), setgroups(2)
  22 /* LICENSE
  23 /* .ad
  24 /* .fi
  25 /*      The Secure Mailer license must be distributed with this software.
  26 /* AUTHOR(S)
  27 /*      Wietse Venema
  28 /*      IBM T.J. Watson Research
  29 /*      P.O. Box 704
  30 /*      Yorktown Heights, NY 10598, USA
  31 /*--*/
  32
  33 /* System library. */
  34
  35 #include <sys_defs.h>
  36 #include <unistd.h>
  37 #include <grp.h>
  38 #include <errno.h>
  39
  40 /* Utility library. */
  41
  42 #include "msg.h"
  43 #include "set_ugid.h"
  44
  45 /* set_ugid - set real, effective and saved user and group attributes */
  46
  47 void    set_ugid(uid_t uid, gid_t gid)
  48 {
  49     int     saved_errno = errno;
  50
  51     if (geteuid() != 0)
  52         if (seteuid(0) < 0)
  53             msg_fatal("seteuid(0): %m");
  54     if (setgid(gid) < 0)
  55         msg_fatal("setgid(%ld): %m", (long) gid);
  56     if (setgroups(1, &gid) < 0)
  57         msg_fatal("setgroups(1, &%ld): %m", (long) gid);
  58     if (setuid(uid) < 0)
  59         msg_fatal("setuid(%ld): %m", (long) uid);
  60     if (msg_verbose > 1)
  61         msg_info("setugid: uid %ld gid %ld", (long) uid, (long) gid);
  62     errno = saved_errno;
  63 }