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nfsd4: fix null dereference creating nfsv4 callback client

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On setting up the callback to the client, we attempt to use the same
authentication flavor the client did.  We find an rpc cred to use by
calling rpcauth_lookup_credcache(), which assumes that the given
authentication flavor has a credentials cache.  However, this is not
required to be true--in particular, auth_null does not use one.
Instead, we should call the auth's lookup_cred() method.

Without this, a client attempting to mount using nfsv4 and auth_null
triggers a null dereference.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
J. Bruce Fields 2009-09-15 12:22:42 -04:00
parent 4be36ca0ce
commit 886e3b7fe6
1 changed files with 2 additions and 2 deletions
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4
fs/nfsd/nfs4callback.c
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@ -437,6 +437,7 @@ static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
struct auth_cred acred = {
.machine_cred = 1
};
struct rpc_auth *auth = cb->cb_client->cl_auth;
/*
* Note in the gss case this doesn't actually have to wait for a
@ -444,8 +445,7 @@ static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
* non-uptodate cred which the rpc state machine will fill in with
* a refresh_upcall later.
*/
return rpcauth_lookup_credcache(cb->cb_client->cl_auth, &acred,
RPCAUTH_LOOKUP_NEW);
return auth->au_ops->lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
}
void do_probe_callback(struct nfs4_client *clp)