freebsd-dev/sys/kgssapi/gss_impl.c
Rick Macklem 13870d5d7b Piete.Brooks at cl.cam.ac.uk reported via email a crash which was
caused by use of an invalid kgss_gssd_handle during an upcall to
the gssd daemon when it has exited. This patch seems to avoid the
crashes by holding a reference count on the kgss_gssd_handle until
the upcall is done. It also adds a new mutex kgss_gssd_lock used to
make manipulation of kgss_gssd_handle SMP safe.

Tested by:	Illias A. Marinos, Herbert Poeckl
Reviewed by:	jhb
MFC after:	2 weeks
2012-12-18 00:25:48 +00:00

333 lines
8.3 KiB
C

/*-
* Copyright (c) 2008 Isilon Inc http://www.isilon.com/
* Authors: Doug Rabson <dfr@rabson.org>
* Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/syscall.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <kgssapi/gssapi.h>
#include <kgssapi/gssapi_impl.h>
#include <rpc/rpc.h>
#include <rpc/rpc_com.h>
#include <rpc/rpcsec_gss.h>
#include "gssd.h"
#include "kgss_if.h"
MALLOC_DEFINE(M_GSSAPI, "GSS-API", "GSS-API");
/*
* Syscall hooks
*/
static int gssd_syscall_offset = SYS_gssd_syscall;
static struct sysent gssd_syscall_prev_sysent;
MAKE_SYSENT(gssd_syscall);
static bool_t gssd_syscall_registered = FALSE;
struct kgss_mech_list kgss_mechs;
CLIENT *kgss_gssd_handle;
struct mtx kgss_gssd_lock;
static void
kgss_init(void *dummy)
{
int error;
LIST_INIT(&kgss_mechs);
error = syscall_register(&gssd_syscall_offset, &gssd_syscall_sysent,
&gssd_syscall_prev_sysent);
if (error)
printf("Can't register GSSD syscall\n");
else
gssd_syscall_registered = TRUE;
}
SYSINIT(kgss_init, SI_SUB_LOCK, SI_ORDER_FIRST, kgss_init, NULL);
static void
kgss_uninit(void *dummy)
{
if (gssd_syscall_registered)
syscall_deregister(&gssd_syscall_offset,
&gssd_syscall_prev_sysent);
}
SYSUNINIT(kgss_uninit, SI_SUB_LOCK, SI_ORDER_FIRST, kgss_uninit, NULL);
int
sys_gssd_syscall(struct thread *td, struct gssd_syscall_args *uap)
{
struct sockaddr_un sun;
struct netconfig *nconf;
char path[MAXPATHLEN];
int error;
CLIENT *cl, *oldcl;
error = priv_check(td, PRIV_NFS_DAEMON);
if (error)
return (error);
error = copyinstr(uap->path, path, sizeof(path), NULL);
if (error)
return (error);
sun.sun_family = AF_LOCAL;
strcpy(sun.sun_path, path);
sun.sun_len = SUN_LEN(&sun);
nconf = getnetconfigent("local");
cl = clnt_reconnect_create(nconf,
(struct sockaddr *) &sun, GSSD, GSSDVERS,
RPC_MAXDATASIZE, RPC_MAXDATASIZE);
mtx_lock(&kgss_gssd_lock);
oldcl = kgss_gssd_handle;
kgss_gssd_handle = cl;
mtx_unlock(&kgss_gssd_lock);
if (oldcl != NULL) {
CLNT_CLOSE(oldcl);
CLNT_RELEASE(oldcl);
}
return (0);
}
int
kgss_oid_equal(const gss_OID oid1, const gss_OID oid2)
{
if (oid1 == oid2)
return (1);
if (!oid1 || !oid2)
return (0);
if (oid1->length != oid2->length)
return (0);
if (memcmp(oid1->elements, oid2->elements, oid1->length))
return (0);
return (1);
}
void
kgss_install_mech(gss_OID mech_type, const char *name, struct kobj_class *cls)
{
struct kgss_mech *km;
km = malloc(sizeof(struct kgss_mech), M_GSSAPI, M_WAITOK);
km->km_mech_type = mech_type;
km->km_mech_name = name;
km->km_class = cls;
LIST_INSERT_HEAD(&kgss_mechs, km, km_link);
}
void
kgss_uninstall_mech(gss_OID mech_type)
{
struct kgss_mech *km;
LIST_FOREACH(km, &kgss_mechs, km_link) {
if (kgss_oid_equal(km->km_mech_type, mech_type)) {
LIST_REMOVE(km, km_link);
free(km, M_GSSAPI);
return;
}
}
}
gss_OID
kgss_find_mech_by_name(const char *name)
{
struct kgss_mech *km;
LIST_FOREACH(km, &kgss_mechs, km_link) {
if (!strcmp(km->km_mech_name, name)) {
return (km->km_mech_type);
}
}
return (GSS_C_NO_OID);
}
const char *
kgss_find_mech_by_oid(const gss_OID oid)
{
struct kgss_mech *km;
LIST_FOREACH(km, &kgss_mechs, km_link) {
if (kgss_oid_equal(km->km_mech_type, oid)) {
return (km->km_mech_name);
}
}
return (NULL);
}
gss_ctx_id_t
kgss_create_context(gss_OID mech_type)
{
struct kgss_mech *km;
gss_ctx_id_t ctx;
LIST_FOREACH(km, &kgss_mechs, km_link) {
if (kgss_oid_equal(km->km_mech_type, mech_type))
break;
}
if (!km)
return (NULL);
ctx = (gss_ctx_id_t) kobj_create(km->km_class, M_GSSAPI, M_WAITOK);
KGSS_INIT(ctx);
return (ctx);
}
void
kgss_delete_context(gss_ctx_id_t ctx, gss_buffer_t output_token)
{
KGSS_DELETE(ctx, output_token);
kobj_delete((kobj_t) ctx, M_GSSAPI);
}
OM_uint32
kgss_transfer_context(gss_ctx_id_t ctx)
{
struct export_sec_context_res res;
struct export_sec_context_args args;
enum clnt_stat stat;
OM_uint32 maj_stat;
if (!kgss_gssd_handle)
return (GSS_S_FAILURE);
args.ctx = ctx->handle;
bzero(&res, sizeof(res));
stat = gssd_export_sec_context_1(&args, &res, kgss_gssd_handle);
if (stat != RPC_SUCCESS) {
return (GSS_S_FAILURE);
}
maj_stat = KGSS_IMPORT(ctx, res.format, &res.interprocess_token);
ctx->handle = 0;
xdr_free((xdrproc_t) xdr_export_sec_context_res, &res);
return (maj_stat);
}
void
kgss_copy_buffer(const gss_buffer_t from, gss_buffer_t to)
{
to->length = from->length;
if (from->length) {
to->value = malloc(from->length, M_GSSAPI, M_WAITOK);
bcopy(from->value, to->value, from->length);
} else {
to->value = NULL;
}
}
/*
* Acquire the kgss_gssd_handle and return it with a reference count,
* if it is available.
*/
CLIENT *
kgss_gssd_client(void)
{
CLIENT *cl;
mtx_lock(&kgss_gssd_lock);
cl = kgss_gssd_handle;
if (cl != NULL)
CLNT_ACQUIRE(cl);
mtx_unlock(&kgss_gssd_lock);
return (cl);
}
/*
* Kernel module glue
*/
static int
kgssapi_modevent(module_t mod, int type, void *data)
{
int error = 0;
switch (type) {
case MOD_LOAD:
rpc_gss_entries.rpc_gss_secfind = rpc_gss_secfind;
rpc_gss_entries.rpc_gss_secpurge = rpc_gss_secpurge;
rpc_gss_entries.rpc_gss_seccreate = rpc_gss_seccreate;
rpc_gss_entries.rpc_gss_set_defaults = rpc_gss_set_defaults;
rpc_gss_entries.rpc_gss_max_data_length =
rpc_gss_max_data_length;
rpc_gss_entries.rpc_gss_get_error = rpc_gss_get_error;
rpc_gss_entries.rpc_gss_mech_to_oid = rpc_gss_mech_to_oid;
rpc_gss_entries.rpc_gss_oid_to_mech = rpc_gss_oid_to_mech;
rpc_gss_entries.rpc_gss_qop_to_num = rpc_gss_qop_to_num;
rpc_gss_entries.rpc_gss_get_mechanisms = rpc_gss_get_mechanisms;
rpc_gss_entries.rpc_gss_get_versions = rpc_gss_get_versions;
rpc_gss_entries.rpc_gss_is_installed = rpc_gss_is_installed;
rpc_gss_entries.rpc_gss_set_svc_name = rpc_gss_set_svc_name;
rpc_gss_entries.rpc_gss_clear_svc_name = rpc_gss_clear_svc_name;
rpc_gss_entries.rpc_gss_getcred = rpc_gss_getcred;
rpc_gss_entries.rpc_gss_set_callback = rpc_gss_set_callback;
rpc_gss_entries.rpc_gss_clear_callback = rpc_gss_clear_callback;
rpc_gss_entries.rpc_gss_get_principal_name =
rpc_gss_get_principal_name;
rpc_gss_entries.rpc_gss_svc_max_data_length =
rpc_gss_svc_max_data_length;
mtx_init(&kgss_gssd_lock, "kgss_gssd_lock", NULL, MTX_DEF);
break;
case MOD_UNLOAD:
/*
* Unloading of the kgssapi module is not currently supported.
* If somebody wants this, we would need to keep track of
* currently executing threads and make sure the count is 0.
*/
/* FALLTHROUGH */
default:
error = EOPNOTSUPP;
};
return (error);
}
static moduledata_t kgssapi_mod = {
"kgssapi",
kgssapi_modevent,
NULL,
};
DECLARE_MODULE(kgssapi, kgssapi_mod, SI_SUB_VFS, SI_ORDER_ANY);
MODULE_DEPEND(kgssapi, krpc, 1, 1, 1);
MODULE_VERSION(kgssapi, 1);