Re: [PATCH v2 1/2] scsi: iscsi: Add length check for nlattr payload

[Chris Leech <cleech@redhat.com>]

On Tue, Jul 25, 2023 at 10:45:29AM +0800, Lin Ma wrote:
> The current NETLINK_ISCSI netlink parsing loop checks every nlmsg to
> make sure the length is bigger than the sizeof(struct iscsi_uevent) and
> then calls iscsi_if_recv_msg(...).
> 
>   nlh = nlmsg_hdr(skb);
>   if (nlh->nlmsg_len < sizeof(*nlh) + sizeof(*ev) ||
>     skb->len < nlh->nlmsg_len) {
>     break;
>   }
>   ...
>   err = iscsi_if_recv_msg(skb, nlh, &group);
> 
> Hence, in iscsi_if_recv_msg, the nlmsg_data can be safely converted to
> iscsi_uevent as the length is already checked.
> 
> However, in the following parsing, the length of nlattr payload is never
> checked before the payload is converted to other data structures in some
> consumers. A bad one for example is function iscsi_set_path(...) who
> converts the payload to type iscsi_path without any checks.

Thank you for doing the code review on this, I think these changes look
good.

Reviewed-by: Chris Leech <cleech@redhat.com>