nfs4: start callback_ident at idr 1
[ Upstream commit c68a027c05709330fe5b2f50c50d5fa02124b5d8 ]
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: d6870312659d ("nfs4client: convert to idr_alloc()")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 368a6b7..0e11fe8 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -33,7 +33,7 @@
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);