CVE-2026-64308: crypto: ccp - Do not initialize SNP for ioctl(SNP_VLEK_LOAD)

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

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

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

crypto: ccp - Do not initialize SNP for ioctl(SNP_VLEK_LOAD)

Sashiko notes:

> if SEV initialization fails and KVM is actively running normal VMs, could a
> userspace process trigger this code path via /dev/sev ioctls (e.g.,
> SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN
> execution for an active VM trigger a general protection fault and crash the
> host?

The SEV firmware docs for SNP_VLEK_LOAD note:

> On SNP_SHUTDOWN, the VLEK is deleted.

That is, the initialization/shutdown wrapper here is pointless, because the
firmware immediately throws away the key anyway. Instead, refuse to do
anything if SNP has not been previously initialized.

This is an ABI break: before, this was a no-op and almost certainly a
mistake by userspace, and now it returns -ENODEV. ABI compatibility could be
maintained here by simply returning 0 in the check instead.

The Linux kernel CVE team has assigned CVE-2026-64308 to this issue.


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

	Issue introduced in 6.12.75 with commit 1c3506ea8599a3ad1b9aae5cbd573134f8d18db7 and fixed in 6.12.96 with commit 61cf5eef20657bff9ca235fe938a99ce5ff65c06
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 6.18.39 with commit 92567ed9306d5a3d1b007eb4faeff30cc3ffc3e4
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.1.4 with commit 8836801847b9479ac046cb18a24981e1b0b05e9d
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.2-rc1 with commit f91e9dbb5845d1e5abf1028e6df57dcf61583e1b

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-2026-64308
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/crypto/ccp/sev-dev.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/61cf5eef20657bff9ca235fe938a99ce5ff65c06
	https://git.kernel.org/stable/c/92567ed9306d5a3d1b007eb4faeff30cc3ffc3e4
	https://git.kernel.org/stable/c/8836801847b9479ac046cb18a24981e1b0b05e9d
	https://git.kernel.org/stable/c/f91e9dbb5845d1e5abf1028e6df57dcf61583e1b