Описание
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.
Пакеты
| Пакет | Статус | Версия исправления | Релиз | Тип |
|---|---|---|---|---|
| linux | fixed | 7.1.4-1 | package | |
| linux | fixed | 6.12.96-1 | trixie | package |
| linux | not-affected | bookworm | package | |
| linux | not-affected | bullseye | package |
Примечания
https://git.kernel.org/linus/fb1758e74b8061aacfbce7bbb7a7cc650537e167 (7.2-rc1)
EPSS
Связанные уязвимости
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...
A flaw was found in the Linux kernel's crypto: ccp component. A local user, by triggering specific SEV (Secure Encrypted Virtualization) input/output control (ioctl) operations when SEV initialization fails and Kernel-based Virtual Machine (KVM) is actively running virtual machines, could cause the system to zero out a critical hardware register. This could lead to a general protection fault, resulting in a denial of service (DoS) by crashing the host system.
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 a
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 awa...
EPSS