Subject: CVE-2024-46689: soc: qcom: cmd-db: Map shared memory as WC, not WB

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

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

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

soc: qcom: cmd-db: Map shared memory as WC, not WB

Linux does not write into cmd-db region. This region of memory is write
protected by XPU. XPU may sometime falsely detect clean cache eviction
as "write" into the write protected region leading to secure interrupt
which causes an endless loop somewhere in Trust Zone.

The only reason it is working right now is because Qualcomm Hypervisor
maps the same region as Non-Cacheable memory in Stage 2 translation
tables. The issue manifests if we want to use another hypervisor (like
Xen or KVM), which does not know anything about those specific mappings.

Changing the mapping of cmd-db memory from MEMREMAP_WB to MEMREMAP_WT/WC
removes dependency on correct mappings in Stage 2 tables. This patch
fixes the issue by updating the mapping to MEMREMAP_WC.

I tested this on SA8155P with Xen.

The Linux kernel CVE team has assigned CVE-2024-46689 to this issue.

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

	Issue introduced in 4.18 with commit 312416d9171a and fixed in 5.4.283 with commit 0ee9594c9743
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 5.10.225 with commit f5a5a5a0e95f
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 5.15.166 with commit eaff392c1e34
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 6.1.108 with commit d9d48d70e922
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 6.6.49 with commit ef80520be0ff
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 6.10.8 with commit 62c2d63605ca
	Issue introduced in 4.18 with commit 312416d9171a and fixed in 6.11 with commit f9bb896eab22

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-2024-46689
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/soc/qcom/cmd-db.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/0ee9594c974368a17e85a431e9fe1c14fb65c278
	https://git.kernel.org/stable/c/f5a5a5a0e95f36e2792d48e6e4b64e665eb01374
	https://git.kernel.org/stable/c/eaff392c1e34fb77cc61505a31b0191e5e46e271
	https://git.kernel.org/stable/c/d9d48d70e922b272875cda60d2ada89291c840cf
	https://git.kernel.org/stable/c/ef80520be0ff78ae5ed44cb6eee1525e65bebe70
	https://git.kernel.org/stable/c/62c2d63605ca25b5db78a347ed303c0a0a77d5b4
	https://git.kernel.org/stable/c/f9bb896eab221618927ae6a2f1d566567999839d