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Fix NULL dereference in gfn_to_hva_prot()

gfn_to_memslot() can return NULL or invalid slot. We need to check slot
validity before accessing it.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
master
Gleb Natapov 8 years ago
parent
commit
a2ac07fe29
  1. 6
      virt/kvm/kvm_main.c

6
virt/kvm/kvm_main.c

@ -1064,10 +1064,12 @@ EXPORT_SYMBOL_GPL(gfn_to_hva);
unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
if (writable)
unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
if (!kvm_is_error_hva(hva) && writable)
*writable = !memslot_is_readonly(slot);
return __gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL, false);
return hva;
}
static int kvm_read_hva(void *data, void __user *hva, int len)

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