CVE-2026-64309: crypto: ccp - Do not initialize SNP for ioctl(SNP_COMMIT)

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_COMMIT)

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 SNP_COMMIT command does not require the firmware to be in any
particular state. Skip initializing it if it was previously uninitialized.

The SEV-SNP firmware specification doc 56860 does not mention SNP_COMMIT in
Table 5 as a command that is allowed in the UNINIT state, but it is in fact
allowed and a future documentation update will reflect that.

The Linux kernel CVE team has assigned CVE-2026-64309 to this issue.


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

	Issue introduced in 6.12.75 with commit 1c3506ea8599a3ad1b9aae5cbd573134f8d18db7 and fixed in 6.12.96 with commit 74768f73854d647a6462f252dc8782ab8a835211
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 6.18.39 with commit 7a361c74bb12f3398c388905f1d325be642cd36e
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.1.4 with commit 67ed191b4c8bdf432a3f32d1eb302880b4795cd1
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.2-rc1 with commit 5a1364da2f04217a36e2fdfa2db4ee025b383a20

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-2026-64309
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/74768f73854d647a6462f252dc8782ab8a835211
	https://git.kernel.org/stable/c/7a361c74bb12f3398c388905f1d325be642cd36e
	https://git.kernel.org/stable/c/67ed191b4c8bdf432a3f32d1eb302880b4795cd1
	https://git.kernel.org/stable/c/5a1364da2f04217a36e2fdfa2db4ee025b383a20