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* [PATCH][next] KVM: x86: Fix potential fput on a null source_kvm_file
@ 2021-04-30 17:03 Colin King
  2021-05-03 14:05 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2021-04-30 17:03 UTC (permalink / raw)
  To: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
	Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, x86, H . Peter Anvin, Nathan Tempelman, kvm
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

The fget can potentially return null, so the fput on the error return
path can cause a null pointer dereference. Fix this by checking for
a null source_kvm_file before doing a fput.

Addresses-Coverity: ("Dereference null return")
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/x86/kvm/svm/sev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1356ee095cd5..8b11c711a0e4 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1764,7 +1764,8 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd)
 e_source_unlock:
 	mutex_unlock(&source_kvm->lock);
 e_source_put:
-	fput(source_kvm_file);
+	if (source_kvm_file)
+		fput(source_kvm_file);
 	return ret;
 }
 
-- 
2.30.2


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH][next] KVM: x86: Fix potential fput on a null source_kvm_file
  2021-04-30 17:03 [PATCH][next] KVM: x86: Fix potential fput on a null source_kvm_file Colin King
@ 2021-05-03 14:05 ` Paolo Bonzini
  0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-05-03 14:05 UTC (permalink / raw)
  To: Colin King, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
	Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, x86, H . Peter Anvin, Nathan Tempelman, kvm
  Cc: kernel-janitors, linux-kernel

On 30/04/21 19:03, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The fget can potentially return null, so the fput on the error return
> path can cause a null pointer dereference. Fix this by checking for
> a null source_kvm_file before doing a fput.
> 
> Addresses-Coverity: ("Dereference null return")
> Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>   arch/x86/kvm/svm/sev.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 1356ee095cd5..8b11c711a0e4 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1764,7 +1764,8 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd)
>   e_source_unlock:
>   	mutex_unlock(&source_kvm->lock);
>   e_source_put:
> -	fput(source_kvm_file);
> +	if (source_kvm_file)
> +		fput(source_kvm_file);
>   	return ret;
>   }
>   
> 

Queued, thanks.

Paolo


^ permalink raw reply	[flat|nested] 2+ messages in thread

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