linux/net/sunrpc/auth.c
Trond Myklebust fba3bad488 SUNRPC: Move upcall out of auth->au_ops->crcreate()
This fixes a bug whereby if two processes try to look up the same auth_gss
 credential, they may end up creating two creds, and triggering two upcalls
 because the upcall is performed before the credential is added to the
 credcache.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-02-01 12:52:25 -05:00

405 lines
9.4 KiB
C

/*
* 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 struct rpc_authops * auth_flavors[RPC_AUTH_MAXFLAVOR] = {
&authnull_ops, /* AUTH_NULL */
&authunix_ops, /* AUTH_UNIX */
NULL, /* others can be loadable modules */
};
static u32
pseudoflavor_to_flavor(u32 flavor) {
if (flavor >= RPC_AUTH_MAXFLAVOR)
return RPC_AUTH_GSS;
return flavor;
}
int
rpcauth_register(struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
return -EINVAL;
if (auth_flavors[flavor] != NULL)
return -EPERM; /* what else? */
auth_flavors[flavor] = ops;
return 0;
}
int
rpcauth_unregister(struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
return -EINVAL;
if (auth_flavors[flavor] != ops)
return -EPERM; /* what else? */
auth_flavors[flavor] = NULL;
return 0;
}
struct rpc_auth *
rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
{
struct rpc_auth *auth;
struct rpc_authops *ops;
u32 flavor = pseudoflavor_to_flavor(pseudoflavor);
if (flavor >= RPC_AUTH_MAXFLAVOR || !(ops = auth_flavors[flavor]))
return ERR_PTR(-EINVAL);
auth = ops->create(clnt, pseudoflavor);
if (IS_ERR(auth))
return auth;
if (clnt->cl_auth)
rpcauth_destroy(clnt->cl_auth);
clnt->cl_auth = auth;
return auth;
}
void
rpcauth_destroy(struct rpc_auth *auth)
{
if (!atomic_dec_and_test(&auth->au_count))
return;
auth->au_ops->destroy(auth);
}
static DEFINE_SPINLOCK(rpc_credcache_lock);
/*
* Initialize RPC credential cache
*/
int
rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
{
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]);
new->expire = expire;
new->nextgc = jiffies + (expire >> 1);
auth->au_credcache = new;
return 0;
}
/*
* Destroy a list of credentials
*/
static inline
void rpcauth_destroy_credlist(struct hlist_head *head)
{
struct rpc_cred *cred;
while (!hlist_empty(head)) {
cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
hlist_del_init(&cred->cr_hash);
put_rpccred(cred);
}
}
/*
* Clear the RPC credential cache, and delete those credentials
* that are not referenced.
*/
void
rpcauth_free_credcache(struct rpc_auth *auth)
{
struct rpc_cred_cache *cache = auth->au_credcache;
HLIST_HEAD(free);
struct hlist_node *pos, *next;
struct rpc_cred *cred;
int i;
spin_lock(&rpc_credcache_lock);
for (i = 0; i < RPC_CREDCACHE_NR; i++) {
hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
cred = hlist_entry(pos, struct rpc_cred, cr_hash);
__hlist_del(&cred->cr_hash);
hlist_add_head(&cred->cr_hash, &free);
}
}
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
}
static void
rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
{
if (atomic_read(&cred->cr_count) != 1)
return;
if (time_after(jiffies, cred->cr_expire + auth->au_credcache->expire))
cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
if (!(cred->cr_flags & RPCAUTH_CRED_UPTODATE)) {
__hlist_del(&cred->cr_hash);
hlist_add_head(&cred->cr_hash, free);
}
}
/*
* Remove stale credentials. Avoid sleeping inside the loop.
*/
static void
rpcauth_gc_credcache(struct rpc_auth *auth, struct hlist_head *free)
{
struct rpc_cred_cache *cache = auth->au_credcache;
struct hlist_node *pos, *next;
struct rpc_cred *cred;
int i;
dprintk("RPC: gc'ing RPC credentials for auth %p\n", auth);
for (i = 0; i < RPC_CREDCACHE_NR; i++) {
hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
cred = hlist_entry(pos, struct rpc_cred, cr_hash);
rpcauth_prune_expired(auth, cred, free);
}
}
cache->nextgc = jiffies + cache->expire;
}
/*
* 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)
{
struct rpc_cred_cache *cache = auth->au_credcache;
HLIST_HEAD(free);
struct hlist_node *pos, *next;
struct rpc_cred *new = NULL,
*cred = NULL;
int nr = 0;
if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
nr = acred->uid & RPC_CREDCACHE_MASK;
retry:
spin_lock(&rpc_credcache_lock);
if (time_before(cache->nextgc, jiffies))
rpcauth_gc_credcache(auth, &free);
hlist_for_each_safe(pos, next, &cache->hashtable[nr]) {
struct rpc_cred *entry;
entry = hlist_entry(pos, struct rpc_cred, cr_hash);
if (entry->cr_ops->crmatch(acred, entry, flags)) {
hlist_del(&entry->cr_hash);
cred = entry;
break;
}
rpcauth_prune_expired(auth, entry, &free);
}
if (new) {
if (cred)
hlist_add_head(&new->cr_hash, &free);
else
cred = new;
}
if (cred) {
hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
get_rpccred(cred);
}
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
if (!cred) {
new = auth->au_ops->crcreate(auth, acred, flags);
if (!IS_ERR(new)) {
#ifdef RPC_DEBUG
new->cr_magic = RPCAUTH_CRED_MAGIC;
#endif
goto retry;
} else
cred = new;
} else if ((cred->cr_flags & RPCAUTH_CRED_NEW)
&& 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);
}
}
return (struct rpc_cred *) 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;
}
struct rpc_cred *
rpcauth_bindcred(struct rpc_task *task)
{
struct rpc_auth *auth = task->tk_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: %4d looking up %s cred\n",
task->tk_pid, task->tk_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)
{
dprintk("RPC: %4d holding %s cred %p\n",
task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
if (task->tk_msg.rpc_cred)
get_rpccred(task->tk_msg.rpc_cred);
}
void
put_rpccred(struct rpc_cred *cred)
{
cred->cr_expire = jiffies;
if (!atomic_dec_and_test(&cred->cr_count))
return;
cred->cr_ops->crdestroy(cred);
}
void
rpcauth_unbindcred(struct rpc_task *task)
{
struct rpc_cred *cred = task->tk_msg.rpc_cred;
dprintk("RPC: %4d releasing %s cred %p\n",
task->tk_pid, task->tk_auth->au_ops->au_name, cred);
put_rpccred(cred);
task->tk_msg.rpc_cred = NULL;
}
u32 *
rpcauth_marshcred(struct rpc_task *task, u32 *p)
{
struct rpc_cred *cred = task->tk_msg.rpc_cred;
dprintk("RPC: %4d marshaling %s cred %p\n",
task->tk_pid, task->tk_auth->au_ops->au_name, cred);
return cred->cr_ops->crmarshal(task, p);
}
u32 *
rpcauth_checkverf(struct rpc_task *task, u32 *p)
{
struct rpc_cred *cred = task->tk_msg.rpc_cred;
dprintk("RPC: %4d validating %s cred %p\n",
task->tk_pid, task->tk_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,
u32 *data, void *obj)
{
struct rpc_cred *cred = task->tk_msg.rpc_cred;
dprintk("RPC: %4d 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,
u32 *data, void *obj)
{
struct rpc_cred *cred = task->tk_msg.rpc_cred;
dprintk("RPC: %4d 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: %4d refreshing %s cred %p\n",
task->tk_pid, task->tk_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)
{
dprintk("RPC: %4d invalidating %s cred %p\n",
task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
spin_lock(&rpc_credcache_lock);
if (task->tk_msg.rpc_cred)
task->tk_msg.rpc_cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
spin_unlock(&rpc_credcache_lock);
}
int
rpcauth_uptodatecred(struct rpc_task *task)
{
return !(task->tk_msg.rpc_cred) ||
(task->tk_msg.rpc_cred->cr_flags & RPCAUTH_CRED_UPTODATE);
}