Re: [patch] VMCI: integer overflow in vmci_datagram_dispatch()

[walter harms]

Am 29.08.2014 10:42, schrieb Dan Carpenter:
> This is untrusted user data from vmci_host_do_send_datagram() so the
> VMCI_DG_SIZE() macro can have an integer overflow.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> 
> diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c
> index f3cdd90..8226652 100644
> --- a/drivers/misc/vmw_vmci/vmci_datagram.c
> +++ b/drivers/misc/vmw_vmci/vmci_datagram.c
> @@ -328,7 +328,8 @@ int vmci_datagram_dispatch(u32 context_id,
>  
>  	BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24);
>  
> -	if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
> +	if (dg->payload_size > VMCI_MAX_DG_SIZE ||
> +	    VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) {
>  		pr_devel("Payload (size=%llu bytes) too big to send\n",
>  			 (unsigned long long)dg->payload_size);
>  		return VMCI_ERROR_INVALID_ARGS;

Are your sure about that ">" ? maybe ">=" was intended ?

re,
 wh

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