From: Paolo Bonzini <pbonzini@redhat.com>
To: Emanuele Giuseppe Esposito <eesposit@redhat.com>, kvm@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 7/8] nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in struct svm_nested_state
Date: Fri, 22 Oct 2021 09:14:08 +0200 [thread overview]
Message-ID: <419f25f5-41ef-1389-1103-3bbe4aa4ddd3@redhat.com> (raw)
In-Reply-To: <20211011143702.1786568-8-eesposit@redhat.com>
On 11/10/21 16:37, Emanuele Giuseppe Esposito wrote:
> ZE))
> return -EFAULT;
> - if (copy_to_user(&user_vmcb->control, &svm->nested.ctl,
> + nested_copy_vmcb_cache_to_control(&ctl_temp, &svm->nested.ctl);
> + if (copy_to_user(&user_vmcb->control, &ctl_temp,
> sizeof(user_vmcb->control)))
> return -EFAULT;
This needs a memset of ctl_temp so that kernel memory contents are not
leaked to userspace. However, it's also better to avoid large structs
on the stack, and do a quick kzalloc/kfree instead:
- nested_copy_vmcb_cache_to_control(&ctl_temp, &svm->nested.ctl);
- if (copy_to_user(&user_vmcb->control, &ctl_temp,
- sizeof(user_vmcb->control)))
+
+ ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
+ if (!ctl)
+ return -ENOMEM;
+ nested_copy_vmcb_cache_to_control(ctl, &svm->nested.ctl);
+ r = copy_to_user(&user_vmcb->control, ctl,
+ sizeof(user_vmcb->control));
+ kfree(ctl);
+ if (r)
return -EFAULT;
I can do this change when committing too.
Paolo
next prev parent reply other threads:[~2021-10-22 7:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-11 14:36 [PATCH v3 0/8] KVM: nSVM: avoid TOC/TOU race when checking vmcb12 Emanuele Giuseppe Esposito
2021-10-11 14:36 ` [PATCH v3 1/8] KVM: nSVM: move nested_vmcb_check_cr3_cr4 logic in nested_vmcb_valid_sregs Emanuele Giuseppe Esposito
2021-10-11 14:36 ` [PATCH v3 2/8] nSVM: introduce smv->nested.save to cache save area fields Emanuele Giuseppe Esposito
2021-10-22 14:46 ` Maxim Levitsky
2021-10-11 14:36 ` [PATCH v3 3/8] nSVM: rename nested_load_control_from_vmcb12 in nested_copy_vmcb_control_to_cache Emanuele Giuseppe Esposito
2021-10-22 14:46 ` Maxim Levitsky
2021-10-11 14:36 ` [PATCH v3 4/8] nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs() Emanuele Giuseppe Esposito
2021-10-22 7:14 ` Paolo Bonzini
2021-10-22 13:48 ` Emanuele Giuseppe Esposito
2021-10-22 14:48 ` Maxim Levitsky
2021-10-11 14:36 ` [PATCH v3 5/8] nSVM: use svm->nested.save to load vmcb12 registers and avoid TOC/TOU races Emanuele Giuseppe Esposito
2021-10-22 14:48 ` Maxim Levitsky
2021-10-11 14:37 ` [PATCH v3 6/8] nSVM: introduce struct vmcb_ctrl_area_cached Emanuele Giuseppe Esposito
2021-10-22 14:49 ` Maxim Levitsky
2021-10-11 14:37 ` [PATCH v3 7/8] nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in struct svm_nested_state Emanuele Giuseppe Esposito
2021-10-22 7:14 ` Paolo Bonzini [this message]
2021-10-22 14:50 ` Maxim Levitsky
2021-10-11 14:37 ` [PATCH v3 8/8] nSVM: remove unnecessary parameter in nested_vmcb_check_controls Emanuele Giuseppe Esposito
2021-10-22 14:51 ` Maxim Levitsky
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