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Date:   Fri, 3 Nov 2023 12:55:37 +0100
From:   Claudio Imbrenda <imbrenda@linux.ibm.com>
To:     Philipp Stanner <pstanner@redhat.com>
Cc:     Christian Borntraeger <borntraeger@linux.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        David Hildenbrand <david@redhat.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, kvm@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        x86@kernel.org, Dave Airlie <airlied@redhat.com>
Subject: Re: [PATCH 2/3] arch/s390/kvm: copy userspace-array safely
Message-ID: <20231103125537.037bb8c5@p-imbrenda>
In-Reply-To: <20231102181526.43279-3-pstanner@redhat.com>
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        <20231102181526.43279-3-pstanner@redhat.com>
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On Thu,  2 Nov 2023 19:15:25 +0100
Philipp Stanner <pstanner@redhat.com> wrote:

> guestdbg.c utilizes memdup_user() to copy a userspace array. This,
> currently, does not check for an overflow.
> 
> Use the new wrapper memdup_array_user() to copy the array more safely.
> 
> Suggested-by: Dave Airlie <airlied@redhat.com>
> Signed-off-by: Philipp Stanner <pstanner@redhat.com>

Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  arch/s390/kvm/guestdbg.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/kvm/guestdbg.c b/arch/s390/kvm/guestdbg.c
> index 3765c4223bf9..80879fc73c90 100644
> --- a/arch/s390/kvm/guestdbg.c
> +++ b/arch/s390/kvm/guestdbg.c
> @@ -213,8 +213,8 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu,
>  	else if (dbg->arch.nr_hw_bp > MAX_BP_COUNT)
>  		return -EINVAL;
>  
> -	bp_data = memdup_user(dbg->arch.hw_bp,
> -			      sizeof(*bp_data) * dbg->arch.nr_hw_bp);
> +	bp_data = memdup_array_user(dbg->arch.hw_bp, dbg->arch.nr_hw_bp,
> +				    sizeof(*bp_data));
>  	if (IS_ERR(bp_data))
>  		return PTR_ERR(bp_data);
>