/* * 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/sunrpc/clnt.h> #include <linux/spinlock.h> #ifdef RPC_DEBUG # define RPCDBG_FACILITY RPCDBG_AUTH #endif 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; 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; } 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; } 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; #ifdef CONFIG_KMOD if ((ops = auth_flavors[flavor]) == NULL) request_module("rpc-auth-%u", flavor); #endif 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; } 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 void rpcauth_unhash_cred(struct rpc_cred *cred) { spinlock_t *cache_lock; cache_lock = &cred->cr_auth->au_credcache->lock; spin_lock(cache_lock); if (atomic_read(&cred->cr_count) == 0) rpcauth_unhash_cred_locked(cred); spin_unlock(cache_lock); } /* * Initialize RPC credential cache */ int rpcauth_init_credcache(struct rpc_auth *auth) { struct rpc_cred_cache *new; int i; new = kmalloc(sizeof(*new), GFP_KERNEL); if (!new) return -ENOMEM; for (i = 0; i < RPC_CREDCACHE_NR; i++) INIT_HLIST_HEAD(&new->hashtable[i]); spin_lock_init(&new->lock); auth->au_credcache = new; return 0; } /* * 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; int i; spin_lock(&rpc_credcache_lock); spin_lock(&cache->lock); for (i = 0; i < RPC_CREDCACHE_NR; 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); } } /* * 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; while (!list_empty(&cred_unused)) { cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru); 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); nr_to_scan--; } spin_unlock(cache_lock); if (nr_to_scan == 0) break; } return nr_to_scan; } /* * Run memory cache shrinker. */ static int rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask) { LIST_HEAD(free); int res; if (list_empty(&cred_unused)) return 0; spin_lock(&rpc_credcache_lock); nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan); res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure; 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; int nr = 0; if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS)) nr = acred->uid & RPC_CREDCACHE_MASK; 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; } struct rpc_cred * rpcauth_lookupcred(struct rpc_auth *auth, int flags) { struct auth_cred acred = { .uid = current->fsuid, .gid = current->fsgid, .group_info = current->group_info, }; struct rpc_cred *ret; dprintk("RPC: looking up %s cred\n", auth->au_ops->au_name); get_group_info(acred.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(rpcauth_init_cred); struct rpc_cred * rpcauth_bindcred(struct rpc_task *task) { struct rpc_auth *auth = task->tk_client->cl_auth; struct auth_cred acred = { .uid = current->fsuid, .gid = current->fsgid, .group_info = current->group_info, }; struct rpc_cred *ret; int flags = 0; dprintk("RPC: %5u looking up %s cred\n", task->tk_pid, task->tk_client->cl_auth->au_ops->au_name); get_group_info(acred.group_info); if (task->tk_flags & RPC_TASK_ROOTCREDS) flags |= RPCAUTH_LOOKUP_ROOTCREDS; ret = auth->au_ops->lookup_cred(auth, &acred, flags); if (!IS_ERR(ret)) task->tk_msg.rpc_cred = ret; else task->tk_status = PTR_ERR(ret); put_group_info(acred.group_info); return ret; } void rpcauth_holdcred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_msg.rpc_cred; if (cred != NULL) { get_rpccred(cred); dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, cred); } } void put_rpccred(struct rpc_cred *cred) { /* Fast path for unhashed credentials */ if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) goto need_lock; if (!atomic_dec_and_test(&cred->cr_count)) return; goto out_destroy; need_lock: 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_UPTODATE, &cred->cr_flags) == 0) rpcauth_unhash_cred(cred); else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) { cred->cr_expire = jiffies; list_add_tail(&cred->cr_lru, &cred_unused); number_cred_unused++; spin_unlock(&rpc_credcache_lock); return; } spin_unlock(&rpc_credcache_lock); out_destroy: cred->cr_ops->crdestroy(cred); } void rpcauth_unbindcred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_msg.rpc_cred; dprintk("RPC: %5u releasing %s cred %p\n", task->tk_pid, cred->cr_auth->au_ops->au_name, cred); put_rpccred(cred); task->tk_msg.rpc_cred = NULL; } __be32 * rpcauth_marshcred(struct rpc_task *task, __be32 *p) { struct rpc_cred *cred = task->tk_msg.rpc_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_msg.rpc_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_msg.rpc_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 rpc_call_xdrproc(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_msg.rpc_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 rpc_call_xdrproc(decode, rqstp, data, obj); } int rpcauth_refreshcred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_msg.rpc_cred; int err; 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); if (err < 0) task->tk_status = err; return err; } void rpcauth_invalcred(struct rpc_task *task) { struct rpc_cred *cred = task->tk_msg.rpc_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_msg.rpc_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, }; void __init rpcauth_init_module(void) { rpc_init_authunix(); register_shrinker(&rpc_cred_shrinker); } void __exit rpcauth_remove_module(void) { unregister_shrinker(&rpc_cred_shrinker); }