1 /*

     2 ** Copyright 1998 - 1999 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	<grp.h>

    16 #include	<pwd.h>

    17 #include	<errno.h>

    18 

    19 #include	"auth.h"

    20 

    21 static const char rcsid[]="$Id: changeuidgid.c,v 1.1 2000/04/13 17:55:05 bruce Exp $";

    22 

    23 void authchangegroup(gid_t gid)

    24 {

    25 	if ( setgid(gid))

    26 	{

    27 		perror("setgid");

    28 		authexit(1);

    29 	}

    30 

    31 #if HAVE_SETGROUPS

    32 	if ( getuid() == 0 && setgroups(1, &gid) )

    33 	{

    34 		perror("setgroups");

    35 		authexit(1);

    36 	}

    37 #endif

    38 }

    39 

    40 void authchangeuidgid(uid_t uid, gid_t gid)

    41 {

    42 	authchangegroup(gid);

    43 	if ( setuid(uid))

    44 	{

    45 		perror("setuid");

    46 		authexit(1);

    47 	}

    48 }

    49 

    50 void authchangeusername(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 		authexit(1);

    65 	}

    66 	strcpy(p, uname);

    67 

    68 	errno=ENOENT;

    69 	if ((pw=getpwnam(p)) == 0)

    70 	{

    71 		free(p);

    72 		perror("getpwnam");

    73 		authexit(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 		authexit(1);

    87 	}

    88 

    89 #if HAVE_INITGROUPS

    90 	if ( getuid() == 0 && initgroups(pw->pw_name, changegid) )

    91 	{

    92 		perror("initgroups");

    93 		authexit(1);

    94 	}

    95 #else

    96 #if HAVE_SETGROUPS

    97 	if ( getuid() == 0 && setgroups(1, &changegid) )

    98 	{

    99 		perror("setgroups");

   100 		authexit(1);

   101 	}

   102 #endif

   103 #endif

   104 

   105 	if (setuid(changeuid))

   106 	{

   107 		perror("setuid");

   108 		authexit(1);

   109 	}

   110 }