Subject: CVE-2024-47748: vhost_vdpa: assign irq bypass producer token correctly

From: Greg Kroah-Hartman <[email-masked]>

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

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

vhost_vdpa: assign irq bypass producer token correctly

We used to call irq_bypass_unregister_producer() in
vhost_vdpa_setup_vq_irq() which is problematic as we don't know if the
token pointer is still valid or not.

Actually, we use the eventfd_ctx as the token so the life cycle of the
token should be bound to the VHOST_SET_VRING_CALL instead of
vhost_vdpa_setup_vq_irq() which could be called by set_status().

Fixing this by setting up irq bypass producer's token when handling
VHOST_SET_VRING_CALL and un-registering the producer before calling
vhost_vring_ioctl() to prevent a possible use after free as eventfd
could have been released in vhost_vring_ioctl(). And such registering
and unregistering will only be done if DRIVER_OK is set.

The Linux kernel CVE team has assigned CVE-2024-47748 to this issue.

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

	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 5.10.227 with commit 0c170b1e918b
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 5.15.168 with commit 927a2580208e
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 6.1.113 with commit ec5f1b54ceb2
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 6.6.54 with commit ca64edd7ae93
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 6.10.13 with commit fae9b1776f53
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 6.11.2 with commit 7cf2fb51175c
	Issue introduced in 5.9 with commit 2cf1ba9a4d15 and fixed in 6.12-rc1 with commit 02e9e9366fef

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-2024-47748
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:
	drivers/vhost/vdpa.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/0c170b1e918b9afac25e2bbd01eaa2bfc0ece8c0
	https://git.kernel.org/stable/c/927a2580208e0f9b0b47b08f1c802b7233a7ba3c
	https://git.kernel.org/stable/c/ec5f1b54ceb23475049ada6e7a43452cf4df88d1
	https://git.kernel.org/stable/c/ca64edd7ae93402af2596a952e0d94d545e2b9c0
	https://git.kernel.org/stable/c/fae9b1776f53aab93ab345bdbf653b991aed717d
	https://git.kernel.org/stable/c/7cf2fb51175cafe01df8c43fa15a06194a59c6e2
	https://git.kernel.org/stable/c/02e9e9366fefe461719da5d173385b6685f70319