glibc/sunrpc/auth_unix.c
2011-04-16 21:59:36 -04:00

359 lines
9.6 KiB
C

/*
* Copyright (c) 2010, 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 <rpc/types.h>
#include <rpc/xdr.h>
#include <rpc/auth.h>
#include <rpc/auth_unix.h>
#ifdef USE_IN_LIBIO
# include <wchar.h>
#endif
/*
* 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 *) internal_function;
/*
* 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 (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 (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
internal_function
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;
}