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Commit fc1b356f authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Fix races in rpcauth_create 



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

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 07a2bf1d

net/sunrpc/auth.c

+24 −11
Original line number Diff line number Diff line
@@ -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? */

	spin_lock(&rpc_authflavor_lock);

	if (auth_flavors[flavor] == NULL) {

		auth_flavors[flavor] = ops;

	return 0;

		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? */

	spin_lock(&rpc_authflavor_lock);

	if (auth_flavors[flavor] == ops) {

		auth_flavors[flavor] = NULL;

	return 0;

		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)