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 <cfir@google.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
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struct page **src_p, **dst_p;
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struct kvm_sev_dbg debug;
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unsigned long n;
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int ret, size;
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unsigned int size;
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int ret;
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if (!sev_guest(kvm))
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return -ENOTTY;
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@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
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if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, sizeof(debug)))
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return -EFAULT;
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if (!debug.len || debug.src_uaddr + debug.len < debug.src_uaddr)
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return -EINVAL;
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if (!debug.dst_uaddr)
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return -EINVAL;
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vaddr = debug.src_uaddr;
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size = debug.len;
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vaddr_end = vaddr + size;
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@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
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dst_vaddr,
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len, &argp->error);
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sev_unpin_memory(kvm, src_p, 1);
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sev_unpin_memory(kvm, dst_p, 1);
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sev_unpin_memory(kvm, src_p, n);
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sev_unpin_memory(kvm, dst_p, n);
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if (ret)
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goto err;
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