[PATCH 6.19 231/342] xfrm: iptfs: only publish mode_data after clone setup

Greg Kroah-Hartman
2026-03-31T16:43:03Z

From: Paul Moses <p@1g4.org>

commit d849a2f7309fc0616e79d13b008b0a47e0458b6e upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/xfrm/xfrm_iptfs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/net/xfrm/xfrm_iptfs.c
+++ b/net/xfrm/xfrm_iptfs.c
@@ -2664,9 +2664,6 @@ static int iptfs_clone_state(struct xfrm
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
}
}

+ x->mode_data = xtfs;
+ xtfs->x = x;
+
return 0;
}