Subject: CVE-2024-36910: uio_hv_generic: Don't free decrypted memory

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

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

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

uio_hv_generic: 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 VMBus device UIO 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-2024-36910 to this issue.

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

	Fixed in 6.1.91 with commit dabf12bf9943
	Fixed in 6.6.31 with commit 6466a0f6d235
	Fixed in 6.8.10 with commit fe2c58602354
	Fixed in 6.9 with commit 3d788b2fbe6a

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-2024-36910
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/uio/uio_hv_generic.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/dabf12bf994318d939f70d47cfda30e47abb2c54
	https://git.kernel.org/stable/c/6466a0f6d235c8a18c602cb587160d7e49876db9
	https://git.kernel.org/stable/c/fe2c58602354fbd60680dc42ac3a0b772cda7d23
	https://git.kernel.org/stable/c/3d788b2fbe6a1a1a9e3db09742b90809d51638b7