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SUNRPC: Fix races in rpcauth_create

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See the FIXME: auth_flavors[] really needs a lock and module refcounting.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-06-09 16:15:46 -04:00
parent 07a2bf1da4
commit fc1b356f56
1 changed files with 24 additions and 11 deletions
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35
net/sunrpc/auth.c
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@ -18,6 +18,7 @@
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static DEFINE_SPINLOCK(rpc_authflavor_lock);
static struct rpc_authops * auth_flavors[RPC_AUTH_MAXFLAVOR] = {
&authnull_ops, /* AUTH_NULL */
&authunix_ops, /* AUTH_UNIX */
@ -35,26 +36,34 @@ int
rpcauth_register(struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
int ret = -EPERM;
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;
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(struct rpc_authops *ops)
{
rpc_authflavor_t flavor;
int ret = -EPERM;
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;
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 *
@ -68,15 +77,19 @@ rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
if (flavor >= RPC_AUTH_MAXFLAVOR)
goto out;
/* FIXME - auth_flavors[] really needs an rw lock,
* and module refcounting. */
#ifdef CONFIG_KMOD
if ((ops = auth_flavors[flavor]) == NULL)
request_module("rpc-auth-%u", flavor);
#endif
if ((ops = auth_flavors[flavor]) == NULL)
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)