KVM: x86: Fix potential fput on a null source_kvm_file
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>
Message-Id: <20210430170303.131924-1-colin.king@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1356ee0..8b11c71 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;
}