This is a note to let you know that I've just added the patch titled
hamradio: remove needs_free_netdev to avoid UAF
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hamradio-remove-needs_free_netdev-to-avoid-uaf.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 81b1d548d00bcd028303c4f3150fa753b9b8aa71 Mon Sep 17 00:00:00 2001
From: Lin Ma <linma@xxxxxxxxxx>
Date: Thu, 11 Nov 2021 22:14:02 +0800
Subject: hamradio: remove needs_free_netdev to avoid UAF
From: Lin Ma <linma@xxxxxxxxxx>
commit 81b1d548d00bcd028303c4f3150fa753b9b8aa71 upstream.
The former patch "defer 6pack kfree after unregister_netdev" reorders
the kfree of two buffer after the unregister_netdev to prevent the race
condition. It also adds free_netdev() function in sixpack_close(), which
is a direct copy from the similar code in mkiss_close().
However, in sixpack driver, the flag needs_free_netdev is set to true in
sp_setup(), hence the unregister_netdev() will free the netdev
automatically. Therefore, as the sp is netdev_priv, use-after-free
occurs.
This patch removes the needs_free_netdev = true and just let the
free_netdev to finish this deallocation task.
Fixes: 0b9111922b1f ("hamradio: defer 6pack kfree after unregister_netdev")
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211111141402.7551-1-linma@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Ovidiu Panait <ovidiu.panait@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/hamradio/6pack.c | 1 -
1 file changed, 1 deletion(-)
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -311,7 +311,6 @@ static void sp_setup(struct net_device *
{
/* Finish setting up the DEVICE info. */
dev->netdev_ops = &sp_netdev_ops;
- dev->needs_free_netdev = true;
dev->mtu = SIXP_MTU;
dev->hard_header_len = AX25_MAX_HEADER_LEN;
dev->header_ops = &ax25_header_ops;
Patches currently in stable-queue which might be from linma@xxxxxxxxxx are
queue-4.14/hamradio-remove-needs_free_netdev-to-avoid-uaf.patch
queue-4.14/hamradio-defer-6pack-kfree-after-unregister_netdev.patch
