From: Ashish Kalra ashish.kalra@amd.com
commit d22d2474e3953996f03528b84b7f52cc26a39403 upstream.
For some sev ioctl interfaces, the length parameter that is passed maybe less than or equal to SEV_FW_BLOB_MAX_SIZE, but larger than the data that PSP firmware returns. In this case, kmalloc will allocate memory that is the size of the input rather than the size of the data. Since PSP firmware doesn't fully overwrite the allocated buffer, these sev ioctl interface may return uninitialized kernel slab memory.
Reported-by: Andy Nguyen theflow@google.com Suggested-by: David Rientjes rientjes@google.com Suggested-by: Peter Gonda pgonda@google.com Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: eaf78265a4ab3 ("KVM: SVM: Move SEV code to separate file") Fixes: 2c07ded06427d ("KVM: SVM: add support for SEV attestation command") Fixes: 4cfdd47d6d95a ("KVM: SVM: Add KVM_SEV SEND_START command") Fixes: d3d1af85e2c75 ("KVM: SVM: Add KVM_SEND_UPDATE_DATA command") Fixes: eba04b20e4861 ("KVM: x86: Account a variety of miscellaneous allocations") Signed-off-by: Ashish Kalra ashish.kalra@amd.com Reviewed-by: Peter Gonda pgonda@google.com Message-Id: 20220516154310.3685678-1-Ashish.Kalra@amd.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com [sudip: adjust context] Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/sev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -537,7 +537,7 @@ static int sev_launch_measure(struct kvm }
ret = -ENOMEM; - blob = kmalloc(params.len, GFP_KERNEL_ACCOUNT); + blob = kzalloc(params.len, GFP_KERNEL_ACCOUNT); if (!blob) goto e_free;
@@ -676,7 +676,7 @@ static int __sev_dbg_decrypt_user(struct if (!IS_ALIGNED(dst_paddr, 16) || !IS_ALIGNED(paddr, 16) || !IS_ALIGNED(size, 16)) { - tpage = (void *)alloc_page(GFP_KERNEL); + tpage = (void *)alloc_page(GFP_KERNEL | __GFP_ZERO); if (!tpage) return -ENOMEM;