Pablo Neira Ayuso 9c413a8c8b netfilter: nf_tables: double hook unregistration in netns path
commit f9a43007d3f7ba76d5e7f9421094f00f2ef202f8 upstream.

__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.

[  565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[  565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G            E     5.18.0-rc7+ #27
[  565.253682] Workqueue: netns cleanup_net
[  565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[  565.297120] Call Trace:
[  565.300900]  <TASK>
[  565.304683]  nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[  565.308518]  raw_notifier_call_chain+0x63/0x80
[  565.312386]  unregister_netdevice_many+0x54f/0xb50

Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.

Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-06 08:43:38 +02:00
2022-06-06 08:43:37 +02:00
2021-10-18 20:22:03 -10:00
2022-05-30 09:29:18 +02:00

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.
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