Re: [PATCH 1/1] misc/vmw_vmci: fix filling of the msg and msg_payload in dg_info struct

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jan 10, 2024 at 01:40:42PM +0300, kovalev@altlinux.org wrote:
> From: Vasiliy Kovalev <kovalev@altlinux.org>
> 
> Fix "detected field-spanning write" of memcpy warning that is issued by
> the tracking mechanism __fortify_memcpy_chk, added 2021-04-20
> (f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time)
> 
> Fixes: a110b7ebb9c674 ("VMCI: datagram implementation.")
> Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
> ---
>  drivers/misc/vmw_vmci/vmci_datagram.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
> index f50d22882476f9..27853b31e288b1 100644
> --- a/drivers/misc/vmw_vmci/vmci_datagram.c
> +++ b/drivers/misc/vmw_vmci/vmci_datagram.c
> @@ -234,7 +234,10 @@ static int dg_dispatch_as_host(u32 context_id, struct vmci_datagram *dg)
>  
>  			dg_info->in_dg_host_queue = true;
>  			dg_info->entry = dst_entry;
> -			memcpy(&dg_info->msg, dg, dg_size);
> +			memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
> +			if (dg->payload_size) {
> +				memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
> +			}
>  
>  			INIT_WORK(&dg_info->work, dg_delayed_dispatch);
>  			schedule_work(&dg_info->work);
> @@ -377,7 +380,10 @@ int vmci_datagram_invoke_guest_handler(struct vmci_datagram *dg)
>  
>  		dg_info->in_dg_host_queue = false;
>  		dg_info->entry = dst_entry;
> -		memcpy(&dg_info->msg, dg, VMCI_DG_SIZE(dg));
> +		memcpy(&dg_info->msg, dg, VMCI_DG_HEADERSIZE);
> +		if (dg->payload_size) {
> +			memcpy(dg_info->msg_payload, VMCI_DG_PAYLOAD(dg), dg->payload_size);
> +		}
>  
>  		INIT_WORK(&dg_info->work, dg_delayed_dispatch);
>  		schedule_work(&dg_info->work);
> -- 
> 2.33.8
> 

Hi,

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