Subject: CVE-2024-36911: hv_netvsc: Don't free decrypted memory

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

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

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

hv_netvsc: Don't free decrypted memory

In CoCo VMs it is possible for the untrusted host to cause
set_memory_encrypted() or set_memory_decrypted() to fail such that an
error is returned and the resulting memory is shared. Callers need to
take care to handle these errors to avoid returning decrypted (shared)
memory to the page allocator, which could lead to functional or security
issues.

The netvsc driver could free decrypted/shared pages if
set_memory_decrypted() fails. Check the decrypted field in the gpadl
to decide whether to free the memory.

The Linux kernel CVE team has assigned CVE-2024-36911 to this issue.

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

	Fixed in 6.6.31 with commit a56fe6113263
	Fixed in 6.8.10 with commit 4aaed9dbe8ac
	Fixed in 6.9 with commit bbf9ac34677b

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-2024-36911
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/net/hyperv/netvsc.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/a56fe611326332bf6b7126e5559590c57dcebad4
	https://git.kernel.org/stable/c/4aaed9dbe8acd2b6114458f0498a617283d6275b
	https://git.kernel.org/stable/c/bbf9ac34677b57506a13682b31a2a718934c0e31