From aa2e304cc6a9dc1e17ff558342098b6fa8957040 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Thu, 2 Jul 2009 22:04:48 +0200 Subject: [PATCH] kvm: Work around borken MSR_GET_INDEX_LIST Allocate enough memory for KVM_GET_MSR_INDEX_LIST as older kernels shot far beyond their limits, corrupting user space memory. Signed-off-by: Jan Kiszka Signed-off-by: Anthony Liguori --- target-i386/kvm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 4a3f598..cab9fcc 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -239,8 +239,11 @@ static int kvm_has_msr_star(CPUState *env) if (ret < 0) return 0; - kvm_msr_list = qemu_mallocz(sizeof(msr_list) + - msr_list.nmsrs * sizeof(msr_list.indices[0])); + /* Old kernel modules had a bug and could write beyond the provided + memory. Allocate at least a safe amount of 1K. */ + kvm_msr_list = qemu_mallocz(MAX(1024, sizeof(msr_list) + + msr_list.nmsrs * + sizeof(msr_list.indices[0]))); kvm_msr_list->nmsrs = msr_list.nmsrs; ret = kvm_ioctl(env->kvm_state, KVM_GET_MSR_INDEX_LIST, kvm_msr_list); -- 2.7.4