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KVM: x86/xen: Fix __user pointer handling for hypercall page installation

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The address we give to memdup_user() isn't correctly tagged as __user.
This is harmless enough as it's a one-off use and we're doing exactly
the right thing, but fix it anyway to shut the checker up. Otherwise
it'll whine when the (now legacy) code gets moved around in a later
patch.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
This commit is contained in:
David Woodhouse 2021-02-02 11:05:10 +00:00
parent 1232f8e6c9
commit 92f4d400a4
1 changed files with 5 additions and 3 deletions
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8
arch/x86/kvm/x86.c
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@ -2874,8 +2874,8 @@ static int xen_hvm_config(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm *kvm = vcpu->kvm;
int lm = is_long_mode(vcpu);
u8 *blob_addr = lm ? (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_64
: (u8 *)(long)kvm->arch.xen_hvm_config.blob_addr_32;
u64 blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
: kvm->arch.xen_hvm_config.blob_addr_32;
u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
: kvm->arch.xen_hvm_config.blob_size_32;
u32 page_num = data & ~PAGE_MASK;
@ -2885,7 +2885,9 @@ static int xen_hvm_config(struct kvm_vcpu *vcpu, u64 data)
if (page_num >= blob_size)
return 1;
page = memdup_user(blob_addr + (page_num * PAGE_SIZE), PAGE_SIZE);
blob_addr += page_num * PAGE_SIZE;
page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
if (IS_ERR(page))
return PTR_ERR(page);