CVE-2026-64310: crypto: ccp - Do not initialize SNP for SEV ioctls

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

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

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

crypto: ccp - Do not initialize SNP for SEV ioctls

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?

sev_move_to_init_state() is called for ioctls requiring only SEV firmware:
SEV_PEK_GEN, SEV_PDH_GEN, SEV_PEK_CSR, SEV_PEK_CERT_IMPORT, and
SEV_PDH_CERT_EXPORT. After the firmware command, it does SEV_SHUTDOWN on
the SEV firmware. Since these commands do not require SNP to be
initialized, skip it by calling __sev_platform_init_locked() which only
initializes the SEV firmware. This way SNP is not Initialized at all, and
HSAVE_PA is not cleared.

The previous code saved any SEV initialization firmware error to
init_args.error and then threw it away and hardcoded the return value of
INVALID_PLATFORM_STATE regardless of the real firmware error. This patch
changes it to surface the underlying error, which is hopefully both more
useful and doesn't cause any problems.

Note that it is still safe to call __sev_firmware_shutdown() directly: it
calls __sev_snp_shutdown_locked(), which skips SNP shutdown if SNP was not
initialized.

The Linux kernel CVE team has assigned CVE-2026-64310 to this issue.


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

	Issue introduced in 6.12.75 with commit 1c3506ea8599a3ad1b9aae5cbd573134f8d18db7 and fixed in 6.12.96 with commit 5181e88da99c3d1d41e25db3472a62b8d4b42cdd
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 6.18.39 with commit 9e983d0a74a6a2348e4ce61647ec8a4dfbe198ac
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.1.4 with commit d51207735e7c224cf591fa260c557a451a69a5cf
	Issue introduced in 6.16 with commit ceac7fb89e8da465aec3ac3c20477f912f5c3a6c and fixed in 7.2-rc1 with commit fb1758e74b8061aacfbce7bbb7a7cc650537e167

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-2026-64310
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/5181e88da99c3d1d41e25db3472a62b8d4b42cdd
	https://git.kernel.org/stable/c/9e983d0a74a6a2348e4ce61647ec8a4dfbe198ac
	https://git.kernel.org/stable/c/d51207735e7c224cf591fa260c557a451a69a5cf
	https://git.kernel.org/stable/c/fb1758e74b8061aacfbce7bbb7a7cc650537e167