lkml.org 
[lkml]   [2019]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH][next] Bluetooth: hci_event: Use struct_size() helper
From
Date
On Thu, 2019-02-07 at 18:40 -0600, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
>
> So, change the following form:
>
> sizeof(*ev) + ev->num_hndl * sizeof(struct hci_comp_pkts_info)
>
> to :
>
> struct_size(ev, handles, ev->num_hndl)
>
> This code was detected with the help of Coccinelle.
[]
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
[]
> @@ -3556,8 +3556,8 @@ static void hci_num_comp_pkts_evt(struct hci_dev *hdev, struct sk_buff *skb)
> return;
> }
>
> - if (skb->len < sizeof(*ev) || skb->len < sizeof(*ev) +
> - ev->num_hndl * sizeof(struct hci_comp_pkts_info)) {
> + if (skb->len < sizeof(*ev) ||
> + skb->len < struct_size(ev, handles, ev->num_hndl)) {
> BT_DBG("%s bad parameters", hdev->name);
> return;
> }
> @@ -3644,8 +3644,8 @@ static void hci_num_comp_blocks_evt(struct hci_dev *hdev, struct sk_buff *skb)
> return;
> }
>
> - if (skb->len < sizeof(*ev) || skb->len < sizeof(*ev) +
> - ev->num_hndl * sizeof(struct hci_comp_blocks_info)) {
> + if (skb->len < sizeof(*ev) ||
> + skb->len < struct_size(ev, handles, ev->num_hndl)) {

Unless these are in a real fast path where skb->len < sizeof(*ev)
is pretty likely, it seems a bit redundant as the multiplication
is pretty cheap and num_hndl is unsigned (actually __u8)

This could/should be simply

if (skb->len < struct_size(...))


\
 
 \ /
  Last update: 2019-02-08 05:03    [W:0.049 / U:2.944 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site