/*

 * Copyright (c) 2010, 2011, Oracle America, Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 *       copyright notice, this list of conditions and the following

 *       disclaimer in the documentation and/or other materials

 *       provided with the distribution.

 *     * Neither the name of the "Oracle America, Inc." nor the names of its

 *       contributors may be used to endorse or promote products derived

 *       from this software without specific prior written permission.

 *

 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE

 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * auth_unix.c, Implements UNIX style authentication parameters.

 *

 * The system is very weak.  The client uses no encryption for it's

 * credentials and only sends null verifiers.  The server sends backs

 * null verifiers or optionally a verifier that suggests a new short hand

 * for the credentials.

 */

#include <errno.h>

#include <limits.h>

#include <stdbool.h>

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <libintl.h>

#include <sys/param.h>

#include <wchar.h>

#include <shlib-compat.h>

#include <rpc/types.h>

#include <rpc/xdr.h>

#include <rpc/auth.h>

#include <rpc/auth_unix.h>

/*

 * Unix authenticator operations vector

 */

static void authunix_nextverf (AUTH *);

static bool_t authunix_marshal (AUTH *, XDR *);

static bool_t authunix_validate (AUTH *, struct opaque_auth *);

static bool_t authunix_refresh (AUTH *);

static void authunix_destroy (AUTH *);

static const struct auth_ops auth_unix_ops = {

  authunix_nextverf,

  authunix_marshal,

  authunix_validate,

  authunix_refresh,

  authunix_destroy

};

/*

 * This struct is pointed to by the ah_private field of an auth_handle.

 */

struct audata {

  struct opaque_auth au_origcred;	/* original credentials */

  struct opaque_auth au_shcred;	/* short hand cred */

  u_long au_shfaults;		/* short hand cache faults */

  char au_marshed[MAX_AUTH_BYTES];

  u_int au_mpos;		/* xdr pos at end of marshed */

};

#define	AUTH_PRIVATE(auth)	((struct audata *)auth->ah_private)

static bool_t marshal_new_auth (AUTH *);

/*

 * Create a unix style authenticator.

 * Returns an auth handle with the given stuff in it.

 */

AUTH *

authunix_create (char *machname, uid_t uid, gid_t gid, int len,

		 gid_t *aup_gids)

{

  struct authunix_parms aup;

  char mymem[MAX_AUTH_BYTES];

  struct timeval now;

  XDR xdrs;

  AUTH *auth;

  struct audata *au;

  /*

   * Allocate and set up auth handle

   */

  auth = (AUTH *) mem_alloc (sizeof (*auth));

  au = (struct audata *) mem_alloc (sizeof (*au));

  if (auth == NULL || au == NULL)

    {

no_memory:

      (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));

      mem_free (auth, sizeof (*auth));

      mem_free (au, sizeof (*au));

      return NULL;

    }

  auth->ah_ops = (struct auth_ops *) &auth_unix_ops;

  auth->ah_private = (caddr_t) au;

  auth->ah_verf = au->au_shcred = _null_auth;

  au->au_shfaults = 0;

  /*

   * fill in param struct from the given params

   */

  (void) __gettimeofday (&now, (struct timezone *) 0);

  aup.aup_time = now.tv_sec;

  aup.aup_machname = machname;

  aup.aup_uid = uid;

  aup.aup_gid = gid;

  aup.aup_len = (u_int) len;

  aup.aup_gids = aup_gids;

  /*

   * Serialize the parameters into origcred

   */

  xdrmem_create (&xdrs, mymem, MAX_AUTH_BYTES, XDR_ENCODE);

  if (!xdr_authunix_parms (&xdrs, &aup))

    abort ();

  au->au_origcred.oa_length = len = XDR_GETPOS (&xdrs);

  au->au_origcred.oa_flavor = AUTH_UNIX;

  au->au_origcred.oa_base = mem_alloc ((u_int) len);

  if (au->au_origcred.oa_base == NULL)

    goto no_memory;

  memcpy(au->au_origcred.oa_base, mymem, (u_int) len);

  /*

   * set auth handle to reflect new cred.

   */

  auth->ah_cred = au->au_origcred;

  marshal_new_auth (auth);

  return auth;

}

libc_hidden_nolink_sunrpc (authunix_create, GLIBC_2_0)

/*

 * Returns an auth handle with parameters determined by doing lots of

 * syscalls.

 */

AUTH *

authunix_create_default (void)

{

  char machname[MAX_MACHINE_NAME + 1];

  if (__gethostname (machname, MAX_MACHINE_NAME) == -1)

    abort ();

  machname[MAX_MACHINE_NAME] = 0;

  uid_t uid = __geteuid ();

  gid_t gid = __getegid ();

  int max_nr_groups;

  /* When we have to try a second time, do not use alloca() again.  We

     might have reached the stack limit already.  */

  bool retry = false;

 again:

  /* Ask the kernel how many groups there are exactly.  Note that we

     might have to redo all this if the number of groups has changed

     between the two calls.  */

  max_nr_groups = __getgroups (0, NULL);

  /* Just some random reasonable stack limit.  */

#define ALLOCA_LIMIT (1024 / sizeof (gid_t))

  gid_t *gids = NULL;

  if (max_nr_groups < ALLOCA_LIMIT && ! retry)

    gids = (gid_t *) alloca (max_nr_groups * sizeof (gid_t));

  else

    {

      gids = (gid_t *) malloc (max_nr_groups * sizeof (gid_t));

      if (gids == NULL)

	return NULL;

    }

  int len = __getgroups (max_nr_groups, gids);

  if (len == -1)

    {

      if (errno == EINVAL)

	{

	  /* New groups added in the meantime.  Try again.  */

	  if (max_nr_groups >= ALLOCA_LIMIT || retry)

	    free (gids);

	  retry = true;

	  goto again;

	}

      /* No other error can happen.  */

      abort ();

    }

  /* This braindamaged Sun code forces us here to truncate the

     list of groups to NGRPS members since the code in

     authuxprot.c transforms a fixed array.  Grrr.  */

  AUTH *result = authunix_create (machname, uid, gid, MIN (NGRPS, len), gids);

  if (max_nr_groups >= ALLOCA_LIMIT || retry)

    free (gids);

  return result;

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (authunix_create_default)

#else

libc_hidden_nolink_sunrpc (authunix_create_default, GLIBC_2_0)

#endif

/*

 * authunix operations

 */

static void

authunix_nextverf (AUTH *auth)

{

  /* no action necessary */

}

static bool_t

authunix_marshal (AUTH *auth, XDR *xdrs)

{

  struct audata *au = AUTH_PRIVATE (auth);

  return XDR_PUTBYTES (xdrs, au->au_marshed, au->au_mpos);

}

static bool_t

authunix_validate (AUTH *auth, struct opaque_auth *verf)

{

  struct audata *au;

  XDR xdrs;

  if (verf->oa_flavor == AUTH_SHORT)

    {

      au = AUTH_PRIVATE (auth);

      xdrmem_create (&xdrs, verf->oa_base, verf->oa_length, XDR_DECODE);

      if (au->au_shcred.oa_base != NULL)

	{

	  mem_free (au->au_shcred.oa_base,

		    au->au_shcred.oa_length);

	  au->au_shcred.oa_base = NULL;

	}

      if (xdr_opaque_auth (&xdrs, &au->au_shcred))

	{

	  auth->ah_cred = au->au_shcred;

	}

      else

	{

	  xdrs.x_op = XDR_FREE;

	  (void) xdr_opaque_auth (&xdrs, &au->au_shcred);

	  au->au_shcred.oa_base = NULL;

	  auth->ah_cred = au->au_origcred;

	}

      marshal_new_auth (auth);

    }

  return TRUE;

}

static bool_t

authunix_refresh (AUTH *auth)

{

  struct audata *au = AUTH_PRIVATE (auth);

  struct authunix_parms aup;

  struct timeval now;

  XDR xdrs;

  int stat;

  if (auth->ah_cred.oa_base == au->au_origcred.oa_base)

    {

      /* there is no hope.  Punt */

      return FALSE;

    }

  au->au_shfaults++;

  /* first deserialize the creds back into a struct authunix_parms */

  aup.aup_machname = NULL;

  aup.aup_gids = (gid_t *) NULL;

  xdrmem_create (&xdrs, au->au_origcred.oa_base,

		 au->au_origcred.oa_length, XDR_DECODE);

  stat = xdr_authunix_parms (&xdrs, &aup;;

  if (!stat)

    goto done;

  /* update the time and serialize in place */

  (void) __gettimeofday (&now, (struct timezone *) 0);

  aup.aup_time = now.tv_sec;

  xdrs.x_op = XDR_ENCODE;

  XDR_SETPOS (&xdrs, 0);

  stat = xdr_authunix_parms (&xdrs, &aup;;

  if (!stat)

    goto done;

  auth->ah_cred = au->au_origcred;

  marshal_new_auth (auth);

done:

  /* free the struct authunix_parms created by deserializing */

  xdrs.x_op = XDR_FREE;

  (void) xdr_authunix_parms (&xdrs, &aup;;

  XDR_DESTROY (&xdrs);

  return stat;

}

static void

authunix_destroy (AUTH *auth)

{

  struct audata *au = AUTH_PRIVATE (auth);

  mem_free (au->au_origcred.oa_base, au->au_origcred.oa_length);

  if (au->au_shcred.oa_base != NULL)

    mem_free (au->au_shcred.oa_base, au->au_shcred.oa_length);

  mem_free (auth->ah_private, sizeof (struct audata));

  if (auth->ah_verf.oa_base != NULL)

    mem_free (auth->ah_verf.oa_base, auth->ah_verf.oa_length);

  mem_free ((caddr_t) auth, sizeof (*auth));

}

/*

 * Marshals (pre-serializes) an auth struct.

 * sets private data, au_marshed and au_mpos

 */

static bool_t

marshal_new_auth (AUTH *auth)

{

  XDR xdr_stream;

  XDR *xdrs = &xdr_stream;

  struct audata *au = AUTH_PRIVATE (auth);

  xdrmem_create (xdrs, au->au_marshed, MAX_AUTH_BYTES, XDR_ENCODE);

  if ((!xdr_opaque_auth (xdrs, &(auth->ah_cred))) ||

      (!xdr_opaque_auth (xdrs, &(auth->ah_verf))))

    perror (_("auth_unix.c: Fatal marshalling problem"));

  else

    au->au_mpos = XDR_GETPOS (xdrs);

  XDR_DESTROY (xdrs);

  return TRUE;

}