8d56f00c61
[ Upstream commit dc1c9fd4a8bbe1e06add9053010b652449bfe411 ]
This reverts "netfilter: nf_tables: skip netdev events generated on netns removal".
The problem is that when a veth device is released, the veth release
callback will also queue the peer netns device for removal.
Its possible that the peer netns is also slated for removal. In this
case, the device memory is already released before the pre_exit hook of
the peer netns runs:
BUG: KASAN: slab-use-after-free in nf_hook_entry_head+0x1b8/0x1d0
Read of size 8 at addr ffff88812c0124f0 by task kworker/u8:1/45
Workqueue: netns cleanup_net
Call Trace:
nf_hook_entry_head+0x1b8/0x1d0
__nf_unregister_net_hook+0x76/0x510
nft_netdev_unregister_hooks+0xa0/0x220
__nft_release_hook+0x184/0x490
nf_tables_pre_exit_net+0x12f/0x1b0
..
Order is:
1. First netns is released, veth_dellink() queues peer netns device
for removal
2. peer netns is queued for removal
3. peer netns device is released, unreg event is triggered
4. unreg event is ignored because netns is going down
5. pre_exit hook calls nft_netdev_unregister_hooks but device memory
might be free'd already.
Fixes: 68a3765c659f ("netfilter: nf_tables: skip netdev events generated on netns removal")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.