libs/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
  23 void libmail_changegroup(gid_t gid)
  24 {
  25         if ( setgid(gid))
  26         {
  27                 perror("setgid");
  28                 exit(1);
  29         }
  30
  31 #if HAVE_SETGROUPS
  32         if ( getuid() == 0 && setgroups(1, &gid) )
  33         {
  34                 perror("setgroups");
  35                 exit(1);
  36         }
  37 #endif
  38 }
  39
  40 void libmail_changeuidgid(uid_t uid, gid_t gid)
  41 {
  42         libmail_changegroup(gid);
  43         if ( setuid(uid))
  44         {
  45                 perror("setuid");
  46                 exit(1);
  47         }
  48 }
  49
  50 void libmail_changeusername(const char *uname, const gid_t *forcegrp)
  51 {
  52 struct passwd *pw;
  53 uid_t   changeuid;
  54 gid_t   changegid;
  55
  56 /* uname might be a pointer returned from a previous called to getpw(),
  57 ** and libc has a problem getting it back.
  58 */
  59 char    *p=malloc(strlen(uname)+1);
  60
  61         if (!p)
  62         {
  63                 perror("malloc");
  64                 exit(1);
  65         }
  66         strcpy(p, uname);
  67
  68         errno=ENOENT;
  69         if ((pw=getpwnam(p)) == 0)
  70         {
  71                 free(p);
  72                 perror("getpwnam");
  73                 exit(1);
  74         }
  75         free(p);
  76
  77         changeuid=pw->pw_uid;
  78
  79         if ( !forcegrp )        forcegrp= &pw->pw_gid;
  80
  81         changegid= *forcegrp;
  82
  83         if ( setgid( changegid ))
  84         {
  85                 perror("setgid");
  86                 exit(1);
  87         }
  88
  89 #if HAVE_INITGROUPS
  90         if ( getuid() == 0 && initgroups(pw->pw_name, changegid) )
  91         {
  92                 perror("initgroups");
  93                 exit(1);
  94         }
  95 #else
  96 #if HAVE_SETGROUPS
  97         if ( getuid() == 0 && setgroups(1, &changegid) )
  98         {
  99                 perror("setgroups");
 100                 exit(1);
 101         }
 102 #endif
 103 #endif
 104
 105         if (setuid(changeuid))
 106         {
 107                 perror("setuid");
 108                 exit(1);
 109         }
 110 }