![Trond Myklebust](/assets/img/avatar_default.png)
Somehow, this escaped the previous purge. There should be no need to keep any extra locks in the XDR callbacks. The NFS client XDR code only writes into private objects, whereas all reads of shared objects are confined to fields that do not change, such as filehandles... Ditto for lockd, the NFSv2/v3 client mount code, and rpcbind. The nfsd XDR code may require the BKL, but since it does a synchronous RPC call from a thread that already holds the lock, that issue is moot. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
585 lines
13 KiB
C
585 lines
13 KiB
C
/*
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* linux/net/sunrpc/auth.c
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*
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* Generic RPC client authentication API.
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/hash.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/spinlock.h>
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#ifdef RPC_DEBUG
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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static DEFINE_SPINLOCK(rpc_authflavor_lock);
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static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
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&authnull_ops, /* AUTH_NULL */
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&authunix_ops, /* AUTH_UNIX */
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NULL, /* others can be loadable modules */
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};
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static LIST_HEAD(cred_unused);
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static unsigned long number_cred_unused;
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static u32
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pseudoflavor_to_flavor(u32 flavor) {
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if (flavor >= RPC_AUTH_MAXFLAVOR)
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return RPC_AUTH_GSS;
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return flavor;
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}
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int
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rpcauth_register(const struct rpc_authops *ops)
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{
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rpc_authflavor_t flavor;
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int ret = -EPERM;
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if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
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return -EINVAL;
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spin_lock(&rpc_authflavor_lock);
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if (auth_flavors[flavor] == NULL) {
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auth_flavors[flavor] = ops;
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ret = 0;
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}
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spin_unlock(&rpc_authflavor_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(rpcauth_register);
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int
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rpcauth_unregister(const struct rpc_authops *ops)
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{
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rpc_authflavor_t flavor;
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int ret = -EPERM;
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if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
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return -EINVAL;
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spin_lock(&rpc_authflavor_lock);
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if (auth_flavors[flavor] == ops) {
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auth_flavors[flavor] = NULL;
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ret = 0;
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}
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spin_unlock(&rpc_authflavor_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(rpcauth_unregister);
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struct rpc_auth *
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rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
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{
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struct rpc_auth *auth;
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const struct rpc_authops *ops;
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u32 flavor = pseudoflavor_to_flavor(pseudoflavor);
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auth = ERR_PTR(-EINVAL);
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if (flavor >= RPC_AUTH_MAXFLAVOR)
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goto out;
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if ((ops = auth_flavors[flavor]) == NULL)
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request_module("rpc-auth-%u", flavor);
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spin_lock(&rpc_authflavor_lock);
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ops = auth_flavors[flavor];
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if (ops == NULL || !try_module_get(ops->owner)) {
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spin_unlock(&rpc_authflavor_lock);
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goto out;
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}
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spin_unlock(&rpc_authflavor_lock);
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auth = ops->create(clnt, pseudoflavor);
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module_put(ops->owner);
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if (IS_ERR(auth))
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return auth;
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if (clnt->cl_auth)
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rpcauth_release(clnt->cl_auth);
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clnt->cl_auth = auth;
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out:
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return auth;
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}
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EXPORT_SYMBOL_GPL(rpcauth_create);
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void
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rpcauth_release(struct rpc_auth *auth)
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{
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if (!atomic_dec_and_test(&auth->au_count))
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return;
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auth->au_ops->destroy(auth);
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}
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static DEFINE_SPINLOCK(rpc_credcache_lock);
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static void
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rpcauth_unhash_cred_locked(struct rpc_cred *cred)
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{
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hlist_del_rcu(&cred->cr_hash);
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smp_mb__before_clear_bit();
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clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
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}
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static void
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rpcauth_unhash_cred(struct rpc_cred *cred)
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{
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spinlock_t *cache_lock;
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cache_lock = &cred->cr_auth->au_credcache->lock;
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spin_lock(cache_lock);
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if (atomic_read(&cred->cr_count) == 0)
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rpcauth_unhash_cred_locked(cred);
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spin_unlock(cache_lock);
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}
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/*
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* Initialize RPC credential cache
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*/
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int
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rpcauth_init_credcache(struct rpc_auth *auth)
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{
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struct rpc_cred_cache *new;
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int i;
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new = kmalloc(sizeof(*new), GFP_KERNEL);
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if (!new)
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return -ENOMEM;
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for (i = 0; i < RPC_CREDCACHE_NR; i++)
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INIT_HLIST_HEAD(&new->hashtable[i]);
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spin_lock_init(&new->lock);
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auth->au_credcache = new;
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return 0;
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}
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EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
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/*
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* Destroy a list of credentials
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*/
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static inline
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void rpcauth_destroy_credlist(struct list_head *head)
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{
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struct rpc_cred *cred;
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while (!list_empty(head)) {
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cred = list_entry(head->next, struct rpc_cred, cr_lru);
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list_del_init(&cred->cr_lru);
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put_rpccred(cred);
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}
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}
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/*
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* Clear the RPC credential cache, and delete those credentials
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* that are not referenced.
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*/
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void
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rpcauth_clear_credcache(struct rpc_cred_cache *cache)
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{
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LIST_HEAD(free);
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struct hlist_head *head;
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struct rpc_cred *cred;
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int i;
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spin_lock(&rpc_credcache_lock);
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spin_lock(&cache->lock);
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for (i = 0; i < RPC_CREDCACHE_NR; i++) {
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head = &cache->hashtable[i];
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while (!hlist_empty(head)) {
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cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
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get_rpccred(cred);
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if (!list_empty(&cred->cr_lru)) {
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list_del(&cred->cr_lru);
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number_cred_unused--;
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}
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list_add_tail(&cred->cr_lru, &free);
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rpcauth_unhash_cred_locked(cred);
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}
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}
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spin_unlock(&cache->lock);
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spin_unlock(&rpc_credcache_lock);
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rpcauth_destroy_credlist(&free);
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}
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/*
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* Destroy the RPC credential cache
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*/
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void
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rpcauth_destroy_credcache(struct rpc_auth *auth)
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{
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struct rpc_cred_cache *cache = auth->au_credcache;
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if (cache) {
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auth->au_credcache = NULL;
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rpcauth_clear_credcache(cache);
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kfree(cache);
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}
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}
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EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
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#define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
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/*
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* Remove stale credentials. Avoid sleeping inside the loop.
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*/
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static int
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rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
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{
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spinlock_t *cache_lock;
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struct rpc_cred *cred, *next;
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unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
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list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
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/* Enforce a 60 second garbage collection moratorium */
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if (time_in_range(cred->cr_expire, expired, jiffies) &&
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test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
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continue;
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list_del_init(&cred->cr_lru);
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number_cred_unused--;
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if (atomic_read(&cred->cr_count) != 0)
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continue;
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cache_lock = &cred->cr_auth->au_credcache->lock;
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spin_lock(cache_lock);
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if (atomic_read(&cred->cr_count) == 0) {
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get_rpccred(cred);
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list_add_tail(&cred->cr_lru, free);
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rpcauth_unhash_cred_locked(cred);
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nr_to_scan--;
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}
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spin_unlock(cache_lock);
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if (nr_to_scan == 0)
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break;
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}
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return nr_to_scan;
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}
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/*
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* Run memory cache shrinker.
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*/
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static int
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rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
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{
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LIST_HEAD(free);
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int res;
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if (list_empty(&cred_unused))
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return 0;
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spin_lock(&rpc_credcache_lock);
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nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
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res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
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spin_unlock(&rpc_credcache_lock);
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rpcauth_destroy_credlist(&free);
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return res;
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}
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/*
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* Look up a process' credentials in the authentication cache
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*/
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struct rpc_cred *
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rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
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int flags)
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{
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LIST_HEAD(free);
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struct rpc_cred_cache *cache = auth->au_credcache;
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struct hlist_node *pos;
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struct rpc_cred *cred = NULL,
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*entry, *new;
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unsigned int nr;
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nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
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rcu_read_lock();
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hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
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if (!entry->cr_ops->crmatch(acred, entry, flags))
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continue;
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spin_lock(&cache->lock);
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if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
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spin_unlock(&cache->lock);
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continue;
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}
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cred = get_rpccred(entry);
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spin_unlock(&cache->lock);
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break;
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}
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rcu_read_unlock();
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if (cred != NULL)
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goto found;
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new = auth->au_ops->crcreate(auth, acred, flags);
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if (IS_ERR(new)) {
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cred = new;
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goto out;
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}
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spin_lock(&cache->lock);
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hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
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if (!entry->cr_ops->crmatch(acred, entry, flags))
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continue;
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cred = get_rpccred(entry);
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break;
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}
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if (cred == NULL) {
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cred = new;
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set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
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hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
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} else
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list_add_tail(&new->cr_lru, &free);
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spin_unlock(&cache->lock);
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found:
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if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
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&& cred->cr_ops->cr_init != NULL
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&& !(flags & RPCAUTH_LOOKUP_NEW)) {
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int res = cred->cr_ops->cr_init(auth, cred);
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if (res < 0) {
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put_rpccred(cred);
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cred = ERR_PTR(res);
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}
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}
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rpcauth_destroy_credlist(&free);
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out:
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return cred;
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}
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EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
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struct rpc_cred *
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rpcauth_lookupcred(struct rpc_auth *auth, int flags)
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{
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struct auth_cred acred = {
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.uid = current->fsuid,
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.gid = current->fsgid,
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.group_info = current->group_info,
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};
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struct rpc_cred *ret;
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dprintk("RPC: looking up %s cred\n",
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auth->au_ops->au_name);
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get_group_info(acred.group_info);
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ret = auth->au_ops->lookup_cred(auth, &acred, flags);
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put_group_info(acred.group_info);
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return ret;
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}
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void
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rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
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struct rpc_auth *auth, const struct rpc_credops *ops)
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{
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INIT_HLIST_NODE(&cred->cr_hash);
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INIT_LIST_HEAD(&cred->cr_lru);
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atomic_set(&cred->cr_count, 1);
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cred->cr_auth = auth;
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cred->cr_ops = ops;
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cred->cr_expire = jiffies;
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#ifdef RPC_DEBUG
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cred->cr_magic = RPCAUTH_CRED_MAGIC;
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#endif
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cred->cr_uid = acred->uid;
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}
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EXPORT_SYMBOL_GPL(rpcauth_init_cred);
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void
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rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
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{
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task->tk_msg.rpc_cred = get_rpccred(cred);
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dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
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cred->cr_auth->au_ops->au_name, cred);
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}
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EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
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static void
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rpcauth_bind_root_cred(struct rpc_task *task)
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{
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struct rpc_auth *auth = task->tk_client->cl_auth;
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struct auth_cred acred = {
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.uid = 0,
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.gid = 0,
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};
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struct rpc_cred *ret;
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dprintk("RPC: %5u looking up %s cred\n",
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task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
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ret = auth->au_ops->lookup_cred(auth, &acred, 0);
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if (!IS_ERR(ret))
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task->tk_msg.rpc_cred = ret;
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else
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task->tk_status = PTR_ERR(ret);
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}
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static void
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rpcauth_bind_new_cred(struct rpc_task *task)
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{
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struct rpc_auth *auth = task->tk_client->cl_auth;
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struct rpc_cred *ret;
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dprintk("RPC: %5u looking up %s cred\n",
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task->tk_pid, auth->au_ops->au_name);
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ret = rpcauth_lookupcred(auth, 0);
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if (!IS_ERR(ret))
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task->tk_msg.rpc_cred = ret;
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else
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task->tk_status = PTR_ERR(ret);
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}
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void
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rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
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{
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if (cred != NULL)
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cred->cr_ops->crbind(task, cred);
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else if (flags & RPC_TASK_ROOTCREDS)
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rpcauth_bind_root_cred(task);
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else
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rpcauth_bind_new_cred(task);
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}
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void
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put_rpccred(struct rpc_cred *cred)
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{
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/* Fast path for unhashed credentials */
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if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
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goto need_lock;
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if (!atomic_dec_and_test(&cred->cr_count))
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return;
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goto out_destroy;
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need_lock:
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if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
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return;
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if (!list_empty(&cred->cr_lru)) {
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number_cred_unused--;
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list_del_init(&cred->cr_lru);
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}
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if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
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rpcauth_unhash_cred(cred);
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if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
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cred->cr_expire = jiffies;
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list_add_tail(&cred->cr_lru, &cred_unused);
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number_cred_unused++;
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spin_unlock(&rpc_credcache_lock);
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return;
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}
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spin_unlock(&rpc_credcache_lock);
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out_destroy:
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cred->cr_ops->crdestroy(cred);
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}
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EXPORT_SYMBOL_GPL(put_rpccred);
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void
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rpcauth_unbindcred(struct rpc_task *task)
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{
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struct rpc_cred *cred = task->tk_msg.rpc_cred;
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dprintk("RPC: %5u releasing %s cred %p\n",
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task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
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put_rpccred(cred);
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task->tk_msg.rpc_cred = NULL;
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}
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__be32 *
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rpcauth_marshcred(struct rpc_task *task, __be32 *p)
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{
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struct rpc_cred *cred = task->tk_msg.rpc_cred;
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dprintk("RPC: %5u marshaling %s cred %p\n",
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task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
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return cred->cr_ops->crmarshal(task, p);
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}
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__be32 *
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rpcauth_checkverf(struct rpc_task *task, __be32 *p)
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{
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struct rpc_cred *cred = task->tk_msg.rpc_cred;
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dprintk("RPC: %5u validating %s cred %p\n",
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task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
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return cred->cr_ops->crvalidate(task, p);
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}
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int
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rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
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__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 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 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();
|
|
rpc_init_generic_auth();
|
|
register_shrinker(&rpc_cred_shrinker);
|
|
}
|
|
|
|
void __exit rpcauth_remove_module(void)
|
|
{
|
|
unregister_shrinker(&rpc_cred_shrinker);
|
|
}
|