From b86bc2858b389255cd44555ce4b1e427b2b770c0 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 25 Mar 2019 11:47:31 -0700 Subject: KVM: SVM: prevent DBG_DECRYPT and DBG_ENCRYPT overflow This ensures that the address and length provided to DBG_DECRYPT and DBG_ENCRYPT do not cause an overflow. At the same time, pass the actual number of pages pinned in memory to sev_unpin_memory() as a cleanup. Reported-by: Cfir Cohen Signed-off-by: David Rientjes Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 947c35a1e545..e0a791c3d4fc 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) struct page **src_p, **dst_p; struct kvm_sev_dbg debug; unsigned long n; - int ret, size; + unsigned int size; + int ret; if (!sev_guest(kvm)) return -ENOTTY; @@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, sizeof(debug))) return -EFAULT; + if (!debug.len || debug.src_uaddr + debug.len < debug.src_uaddr) + return -EINVAL; + if (!debug.dst_uaddr) + return -EINVAL; + vaddr = debug.src_uaddr; size = debug.len; vaddr_end = vaddr + size; @@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) dst_vaddr, len, &argp->error); - sev_unpin_memory(kvm, src_p, 1); - sev_unpin_memory(kvm, dst_p, 1); + sev_unpin_memory(kvm, src_p, n); + sev_unpin_memory(kvm, dst_p, n); if (ret) goto err; -- cgit v1.2.3-59-g8ed1b