// SPDX-License-Identifier: GPL-2.0-only /* * linux/net/sunrpc/auth.c * * Generic RPC client authentication API. * * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> */ #include <linux/types.h> #include <linux/sched.h> #include <linux/cred.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/hash.h> #include <linux/sunrpc/clnt.h> #include <linux/sunrpc/gss_api.h> #include <linux/spinlock.h> #include <trace/events/sunrpc.h> #define RPC_CREDCACHE_DEFAULT_HASHBITS (4) struct rpc_cred_cache { struct hlist_head *hashtable; unsigned int hashbits; spinlock_t lock; }; static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS; static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = { [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops, [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops, NULL, /* others can be loadable modules */ }; static LIST_HEAD(cred_unused); static unsigned long number_cred_unused; static struct cred machine_cred = { .usage = ATOMIC_INIT(1), #ifdef CONFIG_DEBUG_CREDENTIALS .magic = CRED_MAGIC, #endif }; /* * Return the machine_cred pointer to be used whenever * the a generic machine credential is needed. */ const struct cred *rpc_machine_cred(void) { return &machine_cred; } EXPORT_SYMBOL_GPL(rpc_machine_cred); #define MAX_HASHTABLE_BITS (14) static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp) { unsigned long num; unsigned int nbits; int ret; if (!val) goto out_inval; ret = kstrtoul(val, 0, &num); if (ret) goto out_inval; nbits = fls(num - 1); if (nbits > MAX_HASHTABLE_BITS || nbits < 2) goto out_inval; *(unsigned int *)kp->arg = nbits; return 0; out_inval: return -EINVAL; } static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp) { unsigned int nbits; nbits = *(unsigned int *)kp->arg; return sprintf(buffer, "%u\n", 1U << nbits); } #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int); static const struct kernel_param_ops param_ops_hashtbl_sz = { .set = param_set_hashtbl_sz, .get = param_get_hashtbl_sz, }; module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644); MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size"); static unsigned long auth_max_cred_cachesize = ULONG_MAX; module_param(auth_max_cred_cachesize, ulong, 0644); MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size"); static u32 pseudoflavor_to_flavor(u32 flavor) { if (flavor > RPC_AUTH_MAXFLAVOR) return RPC_AUTH_GSS; return flavor; } int rpcauth_register(const struct rpc_authops *ops) { const struct rpc_authops *old; rpc_authflavor_t flavor; if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR) return -EINVAL; old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops); if (old == NULL || old == ops) return 0; return -EPERM; } EXPORT_SYMBOL_GPL(rpcauth_register); int rpcauth_unregister(const struct rpc_authops *ops) { const struct rpc_authops *old; rpc_authflavor_t flavor; if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR) return -EINVAL; old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL); if (old == ops || old == NULL) return 0; return -EPERM; } EXPORT_SYMBOL_GPL(rpcauth_unregister); static const struct rpc_authops * rpcauth_get_authops(rpc_authflavor_t flavor) { const struct rpc_authops *ops; if (flavor >= RPC_AUTH_MAXFLAVOR) return NULL; rcu_read_lock(); ops = rcu_dereference(auth_flavors[flavor]); if (ops == NULL) { rcu_read_unlock(); request_module("rpc-auth-%u", flavor); rcu_read_lock(); ops = rcu_dereference(auth_flavors[flavor]); if (ops == NULL) goto out; } if (!try_module_get(ops->owner)) ops = NULL; out: rcu_read_unlock(); return ops; } static void rpcauth_put_authops(const struct rpc_authops *ops) { module_put(ops->owner); } /** * rpcauth_get_pseudoflavor - check if security flavor is supported * @flavor: a security flavor * @info: a GSS mech OID, quality of protection, and service value * * Verifies that an appropriate kernel module is available or already loaded. * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is * not supported locally. */ rpc_authflavor_t rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info) { const struct rpc_authops *ops = rpcauth_get_authops(flavor); rpc_authflavor_t pseudoflavor; if (!ops) return RPC_AUTH_MAXFLAVOR; pseudoflavor = flavor; if (ops->info2flavor != NULL) pseudoflavor = ops->info2flavor(info); rpcauth_put_authops(ops); return pseudoflavor; } EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor); /** * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor * @pseudoflavor: GSS pseudoflavor to match * @info: rpcsec_gss_info structure to fill in * * Returns zero and fills in "info" if pseudoflavor matches a * supported mechanism. */ int rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info) { rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor); const struct rpc_authops *ops; int result; ops = rpcauth_get_authops(flavor); if (ops == NULL) return -ENOENT; result = -ENOENT; if (ops->flavor2info != NULL) result = ops->flavor2info(pseudoflavor, info); rpcauth_put_authops(ops); return result; } EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo); struct rpc_auth * rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt) { struct rpc_auth *auth = ERR_PTR(-EINVAL); const struct rpc_authops *ops; u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor); ops = rpcauth_get_authops(flavor); if (ops == NULL) goto out; auth = ops->create(args, clnt); rpcauth_put_authops(ops); if (IS_ERR(auth)) return auth; if (clnt->cl_auth) rpcauth_release(clnt->cl_auth); clnt->cl_auth = auth; out: return auth; } EXPORT_SYMBOL_GPL(rpcauth_create); void rpcauth_release(struct rpc_auth *auth) { if (!refcount_dec_and_test(&auth->au_count)) return; auth->au_ops->destroy(auth); } static DEFINE_SPINLOCK(rpc_credcache_lock); /* * On success, the caller is responsible for freeing the reference * held by the hashtable */ static bool rpcauth_unhash_cred_locked(struct rpc_cred *cred) { if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) return false; hlist_del_rcu(&cred->cr_hash); return true; } static bool rpcauth_unhash_cred(struct rpc_cred *cred) { spinlock_t *cache_lock; bool ret; if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) return false; cache_lock = &cred->cr_auth->au_credcache->lock; spin_lock(cache_lock); ret = rpcauth_unhash_cred_locked(cred); spin_unlock(cache_lock); return ret; } /* * Initialize RPC credential cache */ int rpcauth_init_credcache(struct rpc_auth *auth) { struct rpc_cred_cache *new; unsigned int hashsize; new = kmalloc(sizeof(*new), GFP_KERNEL); if (!new) goto out_nocache; new->hashbits = auth_hashbits; hashsize = 1U << new->hashbits; new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL); if (!new->hashtable) goto out_nohashtbl; spin_lock_init(&new->lock); auth->au_credcache = new; return 0; out_nohashtbl: kfree(new); out_nocache: return -ENOMEM; } EXPORT_SYMBOL_GPL(rpcauth_init_credcache); char * rpcauth_stringify_acceptor(struct rpc_cred *cred) { if (!cred->cr_ops->crstringify_acceptor) return NULL; return cred->cr_ops->crstringify_acceptor(cred); } EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor); /* * Destroy a list of credentials */ static inline void rpcauth_destroy_credlist(struct list_head *head) { struct rpc_cred *cred; while (!list_empty(head)) { cred = list_entry(head->next, struct rpc_cred, cr_lru); list_del_init(&cred->cr_lru); put_rpccred(cred); } } static void rpcauth_lru_add_locked(struct rpc_cred *cred) { if (!list_empty(&cred->cr_lru)) return; number_cred_unused++; list_add_tail(&cred->cr_lru, &cred_unused); } static void rpcauth_lru_add(struct rpc_cred *cred) { if (!list_empty(&cred->cr_lru)) return; spin_lock(&rpc_credcache_lock); rpcauth_lru_add_locked(cred); spin_unlock(&rpc_credcache_lock); } static void rpcauth_lru_remove_locked(struct rpc_cred *cred) { if (list_empty(&cred->cr_lru)) return; number_cred_unused--; list_del_init(&cred->cr_lru); } static void rpcauth_lru_remove(struct rpc_cred *cred) { if (list_empty(&cred->cr_lru)) return; spin_lock(&rpc_credcache_lock); rpcauth_lru_remove_locked(cred); spin_unlock(&rpc_credcache_lock); } /* * Clear the RPC credential cache, and delete those credentials * that are not referenced. */ void rpcauth_clear_credcache(struct rpc_cred_cache *cache) { LIST_HEAD(free); struct hlist_head *head; struct rpc_cred *cred; unsigned int hashsize = 1U << cache->hashbits; int i; spin_lock(&rpc_credcache_lock); spin_lock(&cache->lock); for (i = 0; i < hashsize; i++) { head = &cache->hashtable[i]; while (!hlist_empty(head)) { cred = hlist_entry(head->first, struct rpc_cred, cr_hash); rpcauth_unhash_cred_locked(cred); /* Note: We now hold a reference to cred */ rpcauth_lru_remove_locked(cred); list_add_tail(&cred->cr_lru, &free); } } spin_unlock(&cache->lock); spin_unlock(&rpc_credcache_lock); rpcauth_destroy_credlist(&free); } /* * Destroy the RPC credential cache */ void rpcauth_destroy_credcache(struct rpc_auth *auth) { struct rpc_cred_cache *cache = auth->au_credcache; if (cache) { auth->au_credcache = NULL; rpcauth_clear_credcache(cache); kfree(cache->hashtable); kfree(cache); } } EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache); #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ) /* * Remove stale credentials. Avoid sleeping inside the loop. */ static long rpcauth_prune_expired(struct list_head *free, int nr_to_scan) { struct rpc_cred *cred, *next; unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM; long freed = 0; list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) { if (nr_to_scan-- == 0) break; if (refcount_read(&cred->cr_count) > 1) { rpcauth_lru_remove_locked(cred); continue; } /* * Enforce a 60 second garbage collection moratorium * Note that the cred_unused list must be time-ordered. */ if (!time_in_range(cred->cr_expire, expired, jiffies)) continue; if (!rpcauth_unhash_cred(cred)) continue; rpcauth_lru_remove_locked(cred); freed++; list_add_tail(&cred->cr_lru, free); } return freed ? freed : SHRINK_STOP; } static unsigned long rpcauth_cache_do_shrink(int nr_to_scan) { LIST_HEAD(free); unsigned long freed; spin_lock(&rpc_credcache_lock); freed = rpcauth_prune_expired(&free, nr_to_scan); spin_unlock(&rpc_credcache_lock); rpcauth_destroy_credlist(&free); return freed; } /* * Run memory cache shrinker. */ static unsigned long rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) { if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL) return SHRINK_STOP; /* nothing left, don't come back */ if (list_empty(&cred_unused)) return SHRINK_STOP; return rpcauth_cache_do_shrink(sc->nr_to_scan); } static unsigned long rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { return number_cred_unused * sysctl_vfs_cache_pressure / 100; } static void rpcauth_cache_enforce_limit(void) { unsigned long diff; unsigned int nr_to_scan; if (number_cred_unused <= auth_max_cred_cachesize) return; diff = number_cred_unused - auth_max_cred_cachesize; nr_to_scan = 100; if (diff < nr_to_scan) nr_to_scan = diff; rpcauth_cache_do_shrink(nr_to_scan); } /* * Look up a process' credentials in the authentication cache */ struct rpc_cred * rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred, int flags, gfp_t gfp) { LIST_HEAD(free); struct rpc_cred_cache *cache = auth->au_credcache; struct rpc_cred *cred = NULL, *entry, *new; unsigned int nr; nr = auth->au_ops->hash_cred(acred, cache->hashbits); rcu_read_lock(); hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) { if (!entry->cr_ops->crmatch(acred, entry, flags)) continue; cred = get_rpccred(entry); if (cred) break; } rcu_read_unlock(); if (cred != NULL) goto found; new = auth->au_ops->crcreate(auth, acred, flags, gfp); if (IS_ERR(new)) { cred = new; goto out; } spin_lock(&cache->lock); hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) { if (!entry->cr_ops->crmatch(acred, entry, flags)) continue; cred = get_rpccred(entry); if (cred) break; } if (cred == NULL) { cred = new; set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags); refcount_inc(&cred->cr_count); hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]); } else list_add_tail(&new->cr_lru, &free); spin_unlock(&cache->lock); rpcauth_cache_enforce_limit(); found: if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) && cred->cr_ops->cr_init != NULL && !(flags & RPCAUTH_LOOKUP_NEW)) { int res = cred->cr_ops->cr_init(auth, cred); if (res < 0) { put_rpccred(cred); cred = ERR_PTR(res); } } rpcauth_destroy_credlist(&free); out: return cred; } EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache); struct rpc_cred * rpcauth_lookupcred(struct rpc_auth *auth, int flags) { struct auth_cred acred; struct rpc_cred *ret; const struct cred *cred = current_cred(); memset(&acred, 0, sizeof(acred)); acred.cred = cred; ret = auth->au_ops->lookup_cred(auth, &acred, flags); return ret; } EXPORT_SYMBOL_GPL(rpcauth_lookupcred); void rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred, struct rpc_auth *auth, const struct rpc_credops *ops) { INIT_HLIST_NODE(&cred->cr_hash); INIT_LIST_HEAD(&cred->cr_lru); refcount_set(&cred->cr_count, 1); cred->cr_auth = auth; cred->cr_flags = 0; cred->cr_ops = ops; cred->cr_expire = jiffies; cred->cr_cred = get_cred(acred->cred); } EXPORT_SYMBOL_GPL(rpcauth_init_cred); static struct rpc_cred * rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags) { struct rpc_auth *auth = task->tk_client->cl_auth; struct auth_cred acred = { .cred = get_task_cred(&init_task), }; struct rpc_cred *ret; ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags); put_cred(acred.cred); return ret; } static struct rpc_cred * rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags) { struct rpc_auth *auth = task->tk_client->cl_auth; struct auth_cred acred = { .principal = task->tk_client->cl_principal, .cred = init_task.cred, }; if (!acred.principal) return NULL; return auth->au_ops->lookup_cred(auth, &acred, lookupflags); } static struct rpc_cred * rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags) { struct rpc_auth *auth = task->tk_client->cl_auth; return rpcauth_lookupcred(auth, lookupflags); } static int rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_cred *new = NULL; int lookupflags = 0; struct rpc_auth *auth = task->tk_client->cl_auth; struct auth_cred acred = { .cred = cred, }; if (flags & RPC_TASK_ASYNC) lookupflags |= RPCAUTH_LOOKUP_NEW; if (task->tk_op_cred) /* Task must use exactly this rpc_cred */ new = get_rpccred(task->tk_op_cred); else if (cred != NULL && cred != &machine_cred) new = auth->au_ops->lookup_cred(auth, &acred, lookupflags); else if (cred == &machine_cred) new = rpcauth_bind_machine_cred(task, lookupflags); /* If machine cred couldn't be bound, try a root cred */ if (new) ; else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS)) new = rpcauth_bind_root_cred(task, lookupflags); else if (flags & RPC_TASK_NULLCREDS) new = authnull_ops.lookup_cred(NULL, NULL, 0); else new = rpcauth_bind_new_cred(task, lookupflags); if (IS_ERR(new)) return PTR_ERR(new); put_rpccred(req->rq_cred); req->rq_cred = new; return 0; } void put_rpccred(struct rpc_cred *cred) { if (cred == NULL) return; rcu_read_lock(); if (refcount_dec_and_test(&cred->cr_count)) goto destroy; if (refcount_read(&cred->cr_count) != 1 || !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)) goto out; if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) { cred->cr_expire = jiffies; rpcauth_lru_add(cred); /* Race breaker */ if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))) rpcauth_lru_remove(cred); } else if (rpcauth_unhash_cred(cred)) { rpcauth_lru_remove(cred); if (refcount_dec_and_test(&cred->cr_count)) goto destroy; } out: rcu_read_unlock(); return; destroy: rcu_read_unlock(); cred->cr_ops->crdestroy(cred); } EXPORT_SYMBOL_GPL(put_rpccred); /** * rpcauth_marshcred - Append RPC credential to end of @xdr * @task: controlling RPC task * @xdr: xdr_stream containing initial portion of RPC Call header * * On success, an appropriate verifier is added to @xdr, @xdr is * updated to point past the verifier, and zero is returned. * Otherwise, @xdr is in an undefined state and a negative errno * is returned. */ int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr) { const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops; return ops->crmarshal(task, xdr); } /** * rpcauth_wrap_req_encode - XDR encode the RPC procedure * @task: controlling RPC task * @xdr: stream where on-the-wire bytes are to be marshalled * * On success, @xdr contains the encoded and wrapped message. * Otherwise, @xdr is in an undefined state. */ int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr) { kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode; encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp); return 0; } EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode); /** * rpcauth_wrap_req - XDR encode and wrap the RPC procedure * @task: controlling RPC task * @xdr: stream where on-the-wire bytes are to be marshalled * * On success, @xdr contains the encoded and wrapped message, * and zero is returned. Otherwise, @xdr is in an undefined * state and a negative errno is returned. */ int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr) { const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops; return ops->crwrap_req(task, xdr); } /** * rpcauth_checkverf - Validate verifier in RPC Reply header * @task: controlling RPC task * @xdr: xdr_stream containing RPC Reply header * * On success, @xdr is updated to point past the verifier and * zero is returned. Otherwise, @xdr is in an undefined state * and a negative errno is returned. */ int rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr) { const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops; return ops->crvalidate(task, xdr); } /** * rpcauth_unwrap_resp_decode - Invoke XDR decode function * @task: controlling RPC task * @xdr: stream where the Reply message resides * * Returns zero on success; otherwise a negative errno is returned. */ int rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr) { kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode; return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp); } EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode); /** * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred * @task: controlling RPC task * @xdr: stream where the Reply message resides * * Returns zero on success; otherwise a negative errno is returned. */ int rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr) { const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops; return ops->crunwrap_resp(task, xdr); } bool rpcauth_xmit_need_reencode(struct rpc_task *task) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; if (!cred || !cred->cr_ops->crneed_reencode) return false; return cred->cr_ops->crneed_reencode(task); } int rpcauth_refreshcred(struct rpc_task *task) { struct rpc_cred *cred; int err; cred = task->tk_rqstp->rq_cred; if (cred == NULL) { err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags); if (err < 0) goto out; cred = task->tk_rqstp->rq_cred; } err = cred->cr_ops->crrefresh(task); out: if (err < 0) task->tk_status = err; return err; } void rpcauth_invalcred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; if (cred) clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags); } int rpcauth_uptodatecred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; return cred == NULL || test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0; } static struct shrinker rpc_cred_shrinker = { .count_objects = rpcauth_cache_shrink_count, .scan_objects = rpcauth_cache_shrink_scan, .seeks = DEFAULT_SEEKS, }; int __init rpcauth_init_module(void) { int err; err = rpc_init_authunix(); if (err < 0) goto out1; err = register_shrinker(&rpc_cred_shrinker); if (err < 0) goto out2; return 0; out2: rpc_destroy_authunix(); out1: return err; } void rpcauth_remove_module(void) { rpc_destroy_authunix(); unregister_shrinker(&rpc_cred_shrinker); }