Описание
In the Linux kernel, the following vulnerability has been resolved:
crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)
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?
Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG.
This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options:
- do something like symbol_get() for kvm and refuse to initialize if KVM is loaded
- check each cpu's HSAVE_PA for non-zero data before re-initializing
- once initializatio...
In the Linux kernel, the following vulnerability has been resolved:
crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)
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?
Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG.
This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options:
- do something like symbol_get() for kvm and refuse to initialize if KVM is loaded
- check each cpu's HSAVE_PA for non-zero data before re-initializing
- once initialization has failed, continue to refuse to initialize until the ccp module is unloaded
Ссылки
- https://nvd.nist.gov/vuln/detail/CVE-2026-64307
- https://git.kernel.org/stable/c/08f0e65e784c4b20e6e620dd4f68d8636073a3d2
- https://git.kernel.org/stable/c/20f548cdac94860a164e5ebba4f7e4a01051cb06
- https://git.kernel.org/stable/c/345a6e869b33687e9268044bcaeeefd7c61da675
- https://git.kernel.org/stable/c/441ea32cf2755a0dc593557056b00b7caa0651f5
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) 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? Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG. This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options: * do something like symbol_get() for kvm and refuse to initialize if KVM is loaded * check each cpu's HSAVE_PA for non-zero data before re-initializing * once initialization has fa...
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) 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? Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG. This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options: * do something like symbol_get() for kvm and refuse to initialize if KVM is loaded * check each cpu's HSAVE_PA for non-zero data before re-initializing * once initialization has fa...
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) 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? Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG. This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options: * do something like symbol_get() for kvm and refuse to initialize if KVM is loaded * check each cpu's HSAVE_PA for non-zero data before re-initializing * once initialization h
In the Linux kernel, the following vulnerability has been resolved: c ...
