nfs4: start callback_ident at idr 1

If clp->cl_cb_ident is zero, then nfs_cb_idr_remove_locked() skips removing
it when the nfs_client is freed.  A decoding or server bug can then find
and try to put that first nfs_client which would lead to a crash.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: d687031265 ("nfs4client: convert to idr_alloc()")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Benjamin Coddington 2015-11-20 09:56:20 -05:00 committed by Trond Myklebust
parent 91ab4b4d16
commit c68a027c05

View File

@ -33,7 +33,7 @@ static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
return ret;
idr_preload(GFP_KERNEL);
spin_lock(&nn->nfs_client_lock);
ret = idr_alloc(&nn->cb_ident_idr, clp, 0, 0, GFP_NOWAIT);
ret = idr_alloc(&nn->cb_ident_idr, clp, 1, 0, GFP_NOWAIT);
if (ret >= 0)
clp->cl_cb_ident = ret;
spin_unlock(&nn->nfs_client_lock);