Commit b86bc285 authored by David Rientjes's avatar David Rientjes Committed by Paolo Bonzini
Browse files

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: default avatarCfir Cohen <cfir@google.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ede885ec

arch/x86/kvm/svm.c

+9 −3
Original line number Diff line number Diff line
@@ -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;

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