linux/net/sunrpc/svcauth.c
Chuck Lever 438623a06b SUNRPC: Add svc_rqst::rq_auth_stat
I'd like to take commit 4532608d71 ("SUNRPC: Clean up generic
dispatcher code") even further by using only private local SVC
dispatchers for all kernel RPC services. This change would enable
the removal of the logic that switches between
svc_generic_dispatch() and a service's private dispatcher, and
simplify the invocation of the service's pc_release method
so that humans can visually verify that it is always invoked
properly.

All that will come later.

First, let's provide a better way to return authentication errors
from SVC dispatcher functions. Instead of overloading the dispatch
method's *statp argument, add a field to struct svc_rqst that can
hold an error value.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-08-10 14:18:35 -04:00

233 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/net/sunrpc/svcauth.c
*
* The generic interface for RPC authentication on the server side.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*
* CHANGES
* 19-Apr-2000 Chris Evans - Security fix
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/err.h>
#include <linux/hash.h>
#include <trace/events/sunrpc.h>
#include "sunrpc.h"
#define RPCDBG_FACILITY RPCDBG_AUTH
/*
* Table of authenticators
*/
extern struct auth_ops svcauth_null;
extern struct auth_ops svcauth_unix;
static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = {
[RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null,
[RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix,
};
static struct auth_ops *
svc_get_auth_ops(rpc_authflavor_t flavor)
{
struct auth_ops *aops;
if (flavor >= RPC_AUTH_MAXFLAVOR)
return NULL;
rcu_read_lock();
aops = rcu_dereference(authtab[flavor]);
if (aops != NULL && !try_module_get(aops->owner))
aops = NULL;
rcu_read_unlock();
return aops;
}
static void
svc_put_auth_ops(struct auth_ops *aops)
{
module_put(aops->owner);
}
int
svc_authenticate(struct svc_rqst *rqstp)
{
rpc_authflavor_t flavor;
struct auth_ops *aops;
rqstp->rq_auth_stat = rpc_auth_ok;
flavor = svc_getnl(&rqstp->rq_arg.head[0]);
dprintk("svc: svc_authenticate (%d)\n", flavor);
aops = svc_get_auth_ops(flavor);
if (aops == NULL) {
rqstp->rq_auth_stat = rpc_autherr_badcred;
return SVC_DENIED;
}
rqstp->rq_auth_slack = 0;
init_svc_cred(&rqstp->rq_cred);
rqstp->rq_authop = aops;
return aops->accept(rqstp);
}
EXPORT_SYMBOL_GPL(svc_authenticate);
int svc_set_client(struct svc_rqst *rqstp)
{
rqstp->rq_client = NULL;
return rqstp->rq_authop->set_client(rqstp);
}
EXPORT_SYMBOL_GPL(svc_set_client);
/* A request, which was authenticated, has now executed.
* Time to finalise the credentials and verifier
* and release and resources
*/
int svc_authorise(struct svc_rqst *rqstp)
{
struct auth_ops *aops = rqstp->rq_authop;
int rv = 0;
rqstp->rq_authop = NULL;
if (aops) {
rv = aops->release(rqstp);
svc_put_auth_ops(aops);
}
return rv;
}
int
svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
{
struct auth_ops *old;
int rv = -EINVAL;
if (flavor < RPC_AUTH_MAXFLAVOR) {
old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops);
if (old == NULL || old == aops)
rv = 0;
}
return rv;
}
EXPORT_SYMBOL_GPL(svc_auth_register);
void
svc_auth_unregister(rpc_authflavor_t flavor)
{
if (flavor < RPC_AUTH_MAXFLAVOR)
rcu_assign_pointer(authtab[flavor], NULL);
}
EXPORT_SYMBOL_GPL(svc_auth_unregister);
/**************************************************
* 'auth_domains' are stored in a hash table indexed by name.
* When the last reference to an 'auth_domain' is dropped,
* the object is unhashed and freed.
* If auth_domain_lookup fails to find an entry, it will return
* it's second argument 'new'. If this is non-null, it will
* have been atomically linked into the table.
*/
#define DN_HASHBITS 6
#define DN_HASHMAX (1<<DN_HASHBITS)
static struct hlist_head auth_domain_table[DN_HASHMAX];
static DEFINE_SPINLOCK(auth_domain_lock);
static void auth_domain_release(struct kref *kref)
__releases(&auth_domain_lock)
{
struct auth_domain *dom = container_of(kref, struct auth_domain, ref);
hlist_del_rcu(&dom->hash);
dom->flavour->domain_release(dom);
spin_unlock(&auth_domain_lock);
}
void auth_domain_put(struct auth_domain *dom)
{
kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);
}
EXPORT_SYMBOL_GPL(auth_domain_put);
struct auth_domain *
auth_domain_lookup(char *name, struct auth_domain *new)
{
struct auth_domain *hp;
struct hlist_head *head;
head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
spin_lock(&auth_domain_lock);
hlist_for_each_entry(hp, head, hash) {
if (strcmp(hp->name, name)==0) {
kref_get(&hp->ref);
spin_unlock(&auth_domain_lock);
return hp;
}
}
if (new)
hlist_add_head_rcu(&new->hash, head);
spin_unlock(&auth_domain_lock);
return new;
}
EXPORT_SYMBOL_GPL(auth_domain_lookup);
struct auth_domain *auth_domain_find(char *name)
{
struct auth_domain *hp;
struct hlist_head *head;
head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
rcu_read_lock();
hlist_for_each_entry_rcu(hp, head, hash) {
if (strcmp(hp->name, name)==0) {
if (!kref_get_unless_zero(&hp->ref))
hp = NULL;
rcu_read_unlock();
return hp;
}
}
rcu_read_unlock();
return NULL;
}
EXPORT_SYMBOL_GPL(auth_domain_find);
/**
* auth_domain_cleanup - check that the auth_domain table is empty
*
* On module unload the auth_domain_table must be empty. To make it
* easier to catch bugs which don't clean up domains properly, we
* warn if anything remains in the table at cleanup time.
*
* Note that we cannot proactively remove the domains at this stage.
* The ->release() function might be in a module that has already been
* unloaded.
*/
void auth_domain_cleanup(void)
{
int h;
struct auth_domain *hp;
for (h = 0; h < DN_HASHMAX; h++)
hlist_for_each_entry(hp, &auth_domain_table[h], hash)
pr_warn("svc: domain %s still present at module unload.\n",
hp->name);
}