From: J. Bruce Fields Date: Tue, 15 Sep 2009 16:22:42 +0000 (-0400) Subject: nfsd4: fix null dereference creating nfsv4 callback client X-Git-Tag: v2.6.32-rc1~412^2~16 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=886e3b7fe6054230c89ae078a09565ed183ecc73 nfsd4: fix null dereference creating nfsv4 callback client 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 --- diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 63bb384..4abb882 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -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)