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![Trond Myklebust](/assets/img/avatar_default.png)
Avoid taking the global auth_domain_lock in most lookups of the auth domain by adding an RCU protected lookup. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
204 lines
4.5 KiB
C
204 lines
4.5 KiB
C
/*
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* linux/net/sunrpc/svcauth.c
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*
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* The generic interface for RPC authentication on the server side.
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*
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* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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*
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* CHANGES
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* 19-Apr-2000 Chris Evans - Security fix
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/sunrpc/types.h>
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#include <linux/sunrpc/xdr.h>
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#include <linux/sunrpc/svcsock.h>
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#include <linux/sunrpc/svcauth.h>
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#include <linux/err.h>
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#include <linux/hash.h>
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#define RPCDBG_FACILITY RPCDBG_AUTH
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/*
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* Table of authenticators
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*/
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extern struct auth_ops svcauth_null;
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extern struct auth_ops svcauth_unix;
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static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = {
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[RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null,
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[RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix,
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};
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static struct auth_ops *
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svc_get_auth_ops(rpc_authflavor_t flavor)
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{
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struct auth_ops *aops;
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if (flavor >= RPC_AUTH_MAXFLAVOR)
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return NULL;
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rcu_read_lock();
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aops = rcu_dereference(authtab[flavor]);
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if (aops != NULL && !try_module_get(aops->owner))
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aops = NULL;
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rcu_read_unlock();
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return aops;
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}
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static void
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svc_put_auth_ops(struct auth_ops *aops)
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{
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module_put(aops->owner);
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}
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int
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svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
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{
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rpc_authflavor_t flavor;
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struct auth_ops *aops;
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*authp = rpc_auth_ok;
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flavor = svc_getnl(&rqstp->rq_arg.head[0]);
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dprintk("svc: svc_authenticate (%d)\n", flavor);
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aops = svc_get_auth_ops(flavor);
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if (aops == NULL) {
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*authp = rpc_autherr_badcred;
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return SVC_DENIED;
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}
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rqstp->rq_auth_slack = 0;
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init_svc_cred(&rqstp->rq_cred);
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rqstp->rq_authop = aops;
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return aops->accept(rqstp, authp);
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}
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EXPORT_SYMBOL_GPL(svc_authenticate);
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int svc_set_client(struct svc_rqst *rqstp)
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{
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rqstp->rq_client = NULL;
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return rqstp->rq_authop->set_client(rqstp);
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}
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EXPORT_SYMBOL_GPL(svc_set_client);
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/* A request, which was authenticated, has now executed.
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* Time to finalise the credentials and verifier
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* and release and resources
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*/
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int svc_authorise(struct svc_rqst *rqstp)
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{
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struct auth_ops *aops = rqstp->rq_authop;
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int rv = 0;
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rqstp->rq_authop = NULL;
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if (aops) {
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rv = aops->release(rqstp);
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svc_put_auth_ops(aops);
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}
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return rv;
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}
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int
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svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
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{
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struct auth_ops *old;
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int rv = -EINVAL;
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if (flavor < RPC_AUTH_MAXFLAVOR) {
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old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops);
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if (old == NULL || old == aops)
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rv = 0;
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}
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return rv;
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}
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EXPORT_SYMBOL_GPL(svc_auth_register);
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void
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svc_auth_unregister(rpc_authflavor_t flavor)
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{
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if (flavor < RPC_AUTH_MAXFLAVOR)
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rcu_assign_pointer(authtab[flavor], NULL);
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}
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EXPORT_SYMBOL_GPL(svc_auth_unregister);
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/**************************************************
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* 'auth_domains' are stored in a hash table indexed by name.
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* When the last reference to an 'auth_domain' is dropped,
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* the object is unhashed and freed.
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* If auth_domain_lookup fails to find an entry, it will return
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* it's second argument 'new'. If this is non-null, it will
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* have been atomically linked into the table.
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*/
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#define DN_HASHBITS 6
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#define DN_HASHMAX (1<<DN_HASHBITS)
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static struct hlist_head auth_domain_table[DN_HASHMAX];
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static DEFINE_SPINLOCK(auth_domain_lock);
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static void auth_domain_release(struct kref *kref)
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__releases(&auth_domain_lock)
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{
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struct auth_domain *dom = container_of(kref, struct auth_domain, ref);
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hlist_del_rcu(&dom->hash);
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dom->flavour->domain_release(dom);
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spin_unlock(&auth_domain_lock);
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}
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void auth_domain_put(struct auth_domain *dom)
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{
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kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);
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}
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EXPORT_SYMBOL_GPL(auth_domain_put);
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struct auth_domain *
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auth_domain_lookup(char *name, struct auth_domain *new)
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{
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struct auth_domain *hp;
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struct hlist_head *head;
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head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
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spin_lock(&auth_domain_lock);
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hlist_for_each_entry(hp, head, hash) {
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if (strcmp(hp->name, name)==0) {
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kref_get(&hp->ref);
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spin_unlock(&auth_domain_lock);
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return hp;
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}
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}
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if (new)
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hlist_add_head_rcu(&new->hash, head);
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spin_unlock(&auth_domain_lock);
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return new;
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}
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EXPORT_SYMBOL_GPL(auth_domain_lookup);
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struct auth_domain *auth_domain_find(char *name)
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{
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struct auth_domain *hp;
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struct hlist_head *head;
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head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
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rcu_read_lock();
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hlist_for_each_entry_rcu(hp, head, hash) {
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if (strcmp(hp->name, name)==0) {
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if (!kref_get_unless_zero(&hp->ref))
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hp = NULL;
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rcu_read_unlock();
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return hp;
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}
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}
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rcu_read_unlock();
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return NULL;
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}
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EXPORT_SYMBOL_GPL(auth_domain_find);
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