// 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 * * CHANGES * 19-Apr-2000 Chris Evans - Security fix */ #include #include #include #include #include #include #include #include #include #include "sunrpc.h" #define RPCDBG_FACILITY RPCDBG_AUTH /* * Table of authenticators */ extern struct auth_ops svcauth_null; extern struct auth_ops svcauth_unix; extern struct auth_ops svcauth_tls; 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, [RPC_AUTH_TLS] = (struct auth_ops __force __rcu *)&svcauth_tls, }; 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); } /** * svc_authenticate - Initialize an outgoing credential * @rqstp: RPC execution context * * Return values: * %SVC_OK: XDR encoding of the result can begin * %SVC_DENIED: Credential or verifier is not valid * %SVC_GARBAGE: Failed to decode credential or verifier * %SVC_COMPLETE: GSS context lifetime event; no further action * %SVC_DROP: Drop this request; no further action * %SVC_CLOSE: Like drop, but also close transport connection */ enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp) { struct auth_ops *aops; u32 flavor; rqstp->rq_auth_stat = rpc_auth_ok; /* * Decode the Call credential's flavor field. The credential's * body field is decoded in the chosen ->accept method below. */ if (xdr_stream_decode_u32(&rqstp->rq_arg_stream, &flavor) < 0) return SVC_GARBAGE; 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); /** * svc_set_client - Assign an appropriate 'auth_domain' as the client * @rqstp: RPC execution context * * Return values: * %SVC_OK: Client was found and assigned * %SVC_DENY: Client was explicitly denied * %SVC_DROP: Ignore this request * %SVC_CLOSE: Ignore this request and close the connection */ enum svc_auth_status svc_set_client(struct svc_rqst *rqstp) { rqstp->rq_client = NULL; return rqstp->rq_authop->set_client(rqstp); } EXPORT_SYMBOL_GPL(svc_set_client); /** * svc_authorise - Finalize credentials/verifier and release resources * @rqstp: RPC execution context * * Returns zero on success, or a negative errno. */ 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); /** * svc_auth_flavor - return RPC transaction's RPC_AUTH flavor * @rqstp: RPC transaction context * * Returns an RPC flavor or GSS pseudoflavor. */ rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp) { struct auth_ops *aops = rqstp->rq_authop; if (!aops->pseudoflavor) return aops->flavour; return aops->pseudoflavor(rqstp); } EXPORT_SYMBOL_GPL(svc_auth_flavor); /************************************************** * '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<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); }