/* * 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/module.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/hash.h> #include <linux/sunrpc/clnt.h> #include <linux/spinlock.h> #ifdef RPC_DEBUG # define RPCDBG_FACILITY RPCDBG_AUTH #endif #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 DEFINE_SPINLOCK(rpc_authflavor_lock); static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = { &authnull_ops, /* AUTH_NULL */ &authunix_ops, /* AUTH_UNIX */ NULL, /* others can be loadable modules */ }; static LIST_HEAD(cred_unused); static unsigned long number_cred_unused; #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 = strict_strtoul(val, 0, &num); if (ret == -EINVAL) goto out_inval; nbits = fls(num); if (num > (1U << nbits)) nbits++; 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", 1U << nbits); } #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int); static 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 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) { rpc_authflavor_t flavor; int ret = -EPERM; if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR) return -EINVAL; spin_lock(&rpc_authflavor_lock); if (auth_flavors[flavor] == NULL) { auth_flavors[flavor] = ops; ret = 0; } spin_unlock(&rpc_authflavor_lock); return ret; } EXPORT_SYMBOL_GPL(rpcauth_register); int rpcauth_unregister(const struct rpc_authops *ops) { rpc_authflavor_t flavor; int ret = -EPERM; if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR) return -EINVAL; spin_lock(&rpc_authflavor_lock); if (auth_flavors[flavor] == ops) { auth_flavors[flavor] = NULL; ret = 0; } spin_unlock(&rpc_authflavor_lock); return ret; } EXPORT_SYMBOL_GPL(rpcauth_unregister); struct rpc_auth * rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt) { struct rpc_auth *auth; const struct rpc_authops *ops; u32 flavor = pseudoflavor_to_flavor(pseudoflavor); auth = ERR_PTR(-EINVAL); if (flavor >= RPC_AUTH_MAXFLAVOR) goto out; if ((ops = auth_flavors[flavor]) == NULL) request_module("rpc-auth-%u", flavor); spin_lock(&rpc_authflavor_lock); ops = auth_flavors[flavor]; if (ops == NULL || !try_module_get(ops->owner)) { spin_unlock(&rpc_authflavor_lock); goto out; } spin_unlock(&rpc_authflavor_lock); auth = ops->create(clnt, pseudoflavor); module_put(ops->owner); 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 (!atomic_dec_and_test(&auth->au_count)) return; auth->au_ops->destroy(auth); } static DEFINE_SPINLOCK(rpc_credcache_lock); static void rpcauth_unhash_cred_locked(struct rpc_cred *cred) { hlist_del_rcu(&cred->cr_hash); smp_mb__before_clear_bit(); clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags); } static int rpcauth_unhash_cred(struct rpc_cred *cred) { spinlock_t *cache_lock; int ret; cache_lock = &cred->cr_auth->au_credcache->lock; spin_lock(cache_lock); ret = atomic_read(&cred->cr_count) == 0; if (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); /* * 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); } } /* * 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); get_rpccred(cred); if (!list_empty(&cred->cr_lru)) { list_del(&cred->cr_lru); number_cred_unused--; } list_add_tail(&cred->cr_lru, &free); rpcauth_unhash_cred_locked(cred); } } 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 int rpcauth_prune_expired(struct list_head *free, int nr_to_scan) { spinlock_t *cache_lock; struct rpc_cred *cred, *next; unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM; list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) { if (nr_to_scan-- == 0) break; /* * 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) && test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) return 0; list_del_init(&cred->cr_lru); number_cred_unused--; if (atomic_read(&cred->cr_count) != 0) continue; cache_lock = &cred->cr_auth->au_credcache->lock; spin_lock(cache_lock); if (atomic_read(&cred->cr_count) == 0) { get_rpccred(cred); list_add_tail(&cred->cr_lru, free); rpcauth_unhash_cred_locked(cred); } spin_unlock(cache_lock); } return (number_cred_unused / 100) * sysctl_vfs_cache_pressure; } /* * Run memory cache shrinker. */ static int rpcauth_cache_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask) { LIST_HEAD(free); int res; if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL) return (nr_to_scan == 0) ? 0 : -1; if (list_empty(&cred_unused)) return 0; spin_lock(&rpc_credcache_lock); res = rpcauth_prune_expired(&free, nr_to_scan); spin_unlock(&rpc_credcache_lock); rpcauth_destroy_credlist(&free); return res; } /* * 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) { LIST_HEAD(free); struct rpc_cred_cache *cache = auth->au_credcache; struct hlist_node *pos; struct rpc_cred *cred = NULL, *entry, *new; unsigned int nr; nr = hash_long(acred->uid, cache->hashbits); rcu_read_lock(); hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) { if (!entry->cr_ops->crmatch(acred, entry, flags)) continue; spin_lock(&cache->lock); if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) { spin_unlock(&cache->lock); continue; } cred = get_rpccred(entry); spin_unlock(&cache->lock); break; } rcu_read_unlock(); if (cred != NULL) goto found; new = auth->au_ops->crcreate(auth, acred, flags); if (IS_ERR(new)) { cred = new; goto out; } spin_lock(&cache->lock); hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) { if (!entry->cr_ops->crmatch(acred, entry, flags)) continue; cred = get_rpccred(entry); break; } if (cred == NULL) { cred = new; set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags); hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]); } else list_add_tail(&new->cr_lru, &free); spin_unlock(&cache->lock); 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(); dprintk("RPC: looking up %s cred\n", auth->au_ops->au_name); memset(&acred, 0, sizeof(acred)); acred.uid = cred->fsuid; acred.gid = cred->fsgid; acred.group_info = get_group_info(((struct cred *)cred)->group_info); ret = auth->au_ops->lookup_cred(auth, &acred, flags); put_group_info(acred.group_info); return ret; } 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); atomic_set(&cred->cr_count, 1); cred->cr_auth = auth; cred->cr_ops = ops; cred->cr_expire = jiffies; #ifdef RPC_DEBUG cred->cr_magic = RPCAUTH_CRED_MAGIC; #endif cred->cr_uid = acred->uid; } EXPORT_SYMBOL_GPL(rpcauth_init_cred); struct rpc_cred * rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags) { dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, cred); return get_rpccred(cred); } EXPORT_SYMBOL_GPL(rpcauth_generic_bind_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 = { .uid = 0, .gid = 0, }; dprintk("RPC: %5u looking up %s cred\n", task->tk_pid, task->tk_client->cl_auth->au_ops->au_name); 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; dprintk("RPC: %5u looking up %s cred\n", task->tk_pid, auth->au_ops->au_name); return rpcauth_lookupcred(auth, lookupflags); } static int rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags) { struct rpc_rqst *req = task->tk_rqstp; struct rpc_cred *new; int lookupflags = 0; if (flags & RPC_TASK_ASYNC) lookupflags |= RPCAUTH_LOOKUP_NEW; if (cred != NULL) new = cred->cr_ops->crbind(task, cred, lookupflags); else if (flags & RPC_TASK_ROOTCREDS) new = rpcauth_bind_root_cred(task, lookupflags); else new = rpcauth_bind_new_cred(task, lookupflags); if (IS_ERR(new)) return PTR_ERR(new); if (req->rq_cred != NULL) put_rpccred(req->rq_cred); req->rq_cred = new; return 0; } void put_rpccred(struct rpc_cred *cred) { /* Fast path for unhashed credentials */ if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) { if (atomic_dec_and_test(&cred->cr_count)) cred->cr_ops->crdestroy(cred); return; } if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock)) return; if (!list_empty(&cred->cr_lru)) { number_cred_unused--; list_del_init(&cred->cr_lru); } if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) { if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) { cred->cr_expire = jiffies; list_add_tail(&cred->cr_lru, &cred_unused); number_cred_unused++; goto out_nodestroy; } if (!rpcauth_unhash_cred(cred)) { /* We were hashed and someone looked us up... */ goto out_nodestroy; } } spin_unlock(&rpc_credcache_lock); cred->cr_ops->crdestroy(cred); return; out_nodestroy: spin_unlock(&rpc_credcache_lock); } EXPORT_SYMBOL_GPL(put_rpccred); __be32 * rpcauth_marshcred(struct rpc_task *task, __be32 *p) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; dprintk("RPC: %5u marshaling %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, cred); return cred->cr_ops->crmarshal(task, p); } __be32 * rpcauth_checkverf(struct rpc_task *task, __be32 *p) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; dprintk("RPC: %5u validating %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, cred); return cred->cr_ops->crvalidate(task, p); } int rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp, __be32 *data, void *obj) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; dprintk("RPC: %5u using %s cred %p to wrap rpc data\n", task->tk_pid, cred->cr_ops->cr_name, cred); if (cred->cr_ops->crwrap_req) return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj); /* By default, we encode the arguments normally. */ return encode(rqstp, data, obj); } int rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp, __be32 *data, void *obj) { struct rpc_cred *cred = task->tk_rqstp->rq_cred; dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n", task->tk_pid, cred->cr_ops->cr_name, cred); if (cred->cr_ops->crunwrap_resp) return cred->cr_ops->crunwrap_resp(task, decode, rqstp, data, obj); /* By default, we decode the arguments normally. */ return decode(rqstp, data, obj); } 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; }; dprintk("RPC: %5u refreshing %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, 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; dprintk("RPC: %5u invalidating %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, 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 = { .shrink = rpcauth_cache_shrinker, .seeks = DEFAULT_SEEKS, }; int __init rpcauth_init_module(void) { int err; err = rpc_init_authunix(); if (err < 0) goto out1; err = rpc_init_generic_auth(); if (err < 0) goto out2; register_shrinker(&rpc_cred_shrinker); return 0; out2: rpc_destroy_authunix(); out1: return err; } void rpcauth_remove_module(void) { rpc_destroy_authunix(); rpc_destroy_generic_auth(); unregister_shrinker(&rpc_cred_shrinker); }