Re: [patch net-next v4 8/9] devlink: add a command to set notification filter and use it for multicasts

[Jiri Pirko <jiri@resnulli.us>]

Mon, Dec 04, 2023 at 08:17:24PM CET, jacob.e.keller@intel.com wrote:
>
>
>> -----Original Message-----
>> From: Jiri Pirko <jiri@resnulli.us>
>> Sent: Monday, December 4, 2023 8:25 AM
>> To: Kitszel, Przemyslaw <przemyslaw.kitszel@intel.com>
>> Cc: kuba@kernel.org; pabeni@redhat.com; davem@davemloft.net;
>> edumazet@google.com; Keller, Jacob E <jacob.e.keller@intel.com>; Hadi Salim,
>> Jamal <jhs@mojatatu.com>; johannes@sipsolutions.net;
>> andriy.shevchenko@linux.intel.com; Nambiar, Amritha
>> <amritha.nambiar@intel.com>; sdf@google.com; horms@kernel.org;
>> netdev@vger.kernel.org
>> Subject: Re: [patch net-next v4 8/9] devlink: add a command to set notification
>> filter and use it for multicasts
>> 
>> Mon, Nov 27, 2023 at 04:40:22PM CET, przemyslaw.kitszel@intel.com wrote:
>> >On 11/23/23 19:15, Jiri Pirko wrote:
>> >> From: Jiri Pirko <jiri@nvidia.com>
>> >>
>> 
>> [...]
>> 
>> 
>> >> diff --git a/net/devlink/netlink.c b/net/devlink/netlink.c
>> >> index fa9afe3e6d9b..33a8e51dea68 100644
>> >> --- a/net/devlink/netlink.c
>> >> +++ b/net/devlink/netlink.c
>> >> @@ -17,6 +17,79 @@ static const struct genl_multicast_group
>> devlink_nl_mcgrps[] = {
>> >>   	[DEVLINK_MCGRP_CONFIG] = { .name =
>> DEVLINK_GENL_MCGRP_CONFIG_NAME },
>> >>   };
>> >> +int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
>> >> +				      struct genl_info *info)
>> >> +{
>> >> +	struct nlattr **attrs = info->attrs;
>> >> +	struct devlink_obj_desc *flt;
>> >> +	size_t data_offset = 0;
>> >> +	size_t data_size = 0;
>> >> +	char *pos;
>> >> +
>> >> +	if (attrs[DEVLINK_ATTR_BUS_NAME])
>> >> +		data_size += nla_len(attrs[DEVLINK_ATTR_BUS_NAME]) + 1;
>> >> +	if (attrs[DEVLINK_ATTR_DEV_NAME])
>> >> +		data_size += nla_len(attrs[DEVLINK_ATTR_DEV_NAME]) + 1;
>> >> +
>> >> +	flt = kzalloc(sizeof(*flt) + data_size, GFP_KERNEL);
>> >
>> >instead of arithmetic here, you could use struct_size()
>> 
>> That is used for flex array, yet I have no flex array here.
>> 
>
>Yea this isn't a flexible array. You could use size_add to ensure that this can't overflow. I don't know what the bound on the attribute sizes is.

Okay, will do that to be on a safe side.

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