From 5e16923b432bfe79fdfb7cd95ed8e63f6438b663 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 3 Dec 2018 11:30:30 +1100 Subject: NFS/SUNRPC: don't lookup machine credential until rpcauth_bindcred(). When NFS creates a machine credential, it is a "generic" credential, not tied to any auth protocol, and is really just a container for the princpal name. This doesn't get linked to a genuine credential until rpcauth_bindcred() is called. The lookup always succeeds, so various places that test if the machine credential is NULL, are pointless. As a step towards getting rid of generic credentials, this patch gets rid of generic machine credentials. The nfs_client and rpc_client just hold a pointer to a constant principal name. When a machine credential is wanted, a special static 'struct rpc_cred' pointer is used. rpcauth_bindcred() recognizes this, finds the principal from the client, and binds the correct credential. Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker --- net/sunrpc/auth.c | 42 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-) (limited to 'net/sunrpc/auth.c') diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c index 63e2d35c10d5..9e709dcc8c39 100644 --- a/net/sunrpc/auth.c +++ b/net/sunrpc/auth.c @@ -39,6 +39,20 @@ static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = { static LIST_HEAD(cred_unused); static unsigned long number_cred_unused; +static struct rpc_cred machine_cred = { + .cr_count = REFCOUNT_INIT(1), +}; + +/* + * Return the machine_cred pointer to be used whenever + * the a generic machine credential is needed. + */ +struct rpc_cred *rpc_machine_cred(void) +{ + return &machine_cred; +} +EXPORT_SYMBOL_GPL(rpc_machine_cred); + #define MAX_HASHTABLE_BITS (14) static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp) { @@ -702,6 +716,22 @@ rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags) return ret; } +static struct rpc_cred * +rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags) +{ + struct rpc_auth *auth = task->tk_client->cl_auth; + struct auth_cred acred = { + .principal = task->tk_client->cl_principal, + .cred = init_task.cred, + }; + + if (!acred.principal) + return NULL; + dprintk("RPC: %5u looking up %s machine cred\n", + task->tk_pid, task->tk_client->cl_auth->au_ops->au_name); + return auth->au_ops->lookup_cred(auth, &acred, lookupflags); +} + static struct rpc_cred * rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags) { @@ -716,14 +746,20 @@ static int rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags) { struct rpc_rqst *req = task->tk_rqstp; - struct rpc_cred *new; + struct rpc_cred *new = NULL; int lookupflags = 0; if (flags & RPC_TASK_ASYNC) lookupflags |= RPCAUTH_LOOKUP_NEW; - if (cred != NULL) + if (cred != NULL && cred != &machine_cred) new = cred->cr_ops->crbind(task, cred, lookupflags); - else if (flags & RPC_TASK_ROOTCREDS) + else if (cred == &machine_cred) + new = rpcauth_bind_machine_cred(task, lookupflags); + + /* If machine cred couldn't be bound, try a root cred */ + if (new) + ; + else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS)) new = rpcauth_bind_root_cred(task, lookupflags); else new = rpcauth_bind_new_cred(task, lookupflags); -- cgit v1.2.3