xfrm: iptfs: only publish mode_data after clone setup

iptfs_clone_state() stores x->mode_data before allocating the reorder
window. If that allocation fails, the code frees the cloned state and
returns -ENOMEM, leaving x->mode_data pointing at freed memory.

The xfrm clone unwind later runs destroy_state() through x->mode_data,
so the failed clone path tears down IPTFS state that clone_state()
already freed.

Keep the cloned IPTFS state private until all allocations succeed so
failed clones leave x->mode_data unset. The destroy path already
handles a NULL mode_data pointer.

Fixes: 6be02e3e4f37 ("xfrm: iptfs: handle reordering of received packets")
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moses <p@1g4.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/xfrm/xfrm_iptfs.c b/net/xfrm/xfrm_iptfs.c
index 2c87290fe06c329d7e15eeb351b34e39a0273fc0..7cd97c1dcd117880a1e98f9652f9af6577a3df94 100644 (file)
--- a/net/xfrm/xfrm_iptfs.c
+++ b/net/xfrm/xfrm_iptfs.c
@@ -2664,9 +2664,6 @@ static int iptfs_clone_state(struct xfrm_state *x, struct xfrm_state *orig)
        if (!xtfs)
                return -ENOMEM;
 
-       x->mode_data = xtfs;
-       xtfs->x = x;
-
        xtfs->ra_newskb = NULL;
        if (xtfs->cfg.reorder_win_size) {
                xtfs->w_saved = kcalloc(xtfs->cfg.reorder_win_size,
@@ -2677,6 +2674,9 @@ static int iptfs_clone_state(struct xfrm_state *x, struct xfrm_state *orig)
                }
        }
 
+       x->mode_data = xtfs;
+       xtfs->x = x;
+
        return 0;
 }