From c68a027c05709330fe5b2f50c50d5fa02124b5d8 Mon Sep 17 00:00:00 2001 From: Benjamin Coddington Date: Fri, 20 Nov 2015 09:56:20 -0500 Subject: [PATCH] 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 Fixes: d6870312659d ("nfs4client: convert to idr_alloc()") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust --- fs/nfs/nfs4client.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c index 223bedda64ae..10410e8b5853 100644 --- a/fs/nfs/nfs4client.c +++ b/fs/nfs/nfs4client.c @@ -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); -- 2.20.1