linux-cve-announce - CVE-2024-50130: netfilter: bpf: must hold reference on net namespace

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Message-ID: <2024110558-CVE-2024-50130-7580@gregkh>
Date: Tue,  5 Nov 2024 18:11:19 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2024-50130: netfilter: bpf: must hold reference on net namespace

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

netfilter: bpf: must hold reference on net namespace

BUG: KASAN: slab-use-after-free in __nf_unregister_net_hook+0x640/0x6b0
Read of size 8 at addr ffff8880106fe400 by task repro/72=
bpf_nf_link_release+0xda/0x1e0
bpf_link_free+0x139/0x2d0
bpf_link_release+0x68/0x80
__fput+0x414/0xb60

Eric says:
 It seems that bpf was able to defer the __nf_unregister_net_hook()
 after exit()/close() time.
 Perhaps a netns reference is missing, because the netns has been
 dismantled/freed already.
 bpf_nf_link_attach() does :
 link->net = net;
 But I do not see a reference being taken on net.

Add such a reference and release it after hook unreg.
Note that I was unable to get syzbot reproducer to work, so I
do not know if this resolves this splat.

The Linux kernel CVE team has assigned CVE-2024-50130 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.4 with commit 84601d6ee68a and fixed in 6.6.59 with commit f41bd93b3e05
	Issue introduced in 6.4 with commit 84601d6ee68a and fixed in 6.11.6 with commit d0d7939543a1
	Issue introduced in 6.4 with commit 84601d6ee68a and fixed in 6.12-rc5 with commit 1230fe7ad397

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-50130
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/netfilter/nf_bpf_link.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f41bd93b3e0508edc7ba820357f949071dcc0acc
	https://git.kernel.org/stable/c/d0d7939543a1b3bb93af9a18d258a774daf8f162
	https://git.kernel.org/stable/c/1230fe7ad3974f7bf6c78901473e039b34d4fb1f