2022-10-28 13:49:56

by Deepak R Varma

[permalink] [raw]
Subject: [PATCH] staging: wlan-ng: Use flexible-array for one / zero-length arrays

Flexible-array member should be used instead of one or zero member to
meet the need for having a dynamically sized trailing elements in a
structure. Refer to links [1] and [2] for detailed guidance on this
suggestion.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Issue identified using coccicheck.

Signed-off-by: Deepak R Varma <[email protected]>
---
drivers/staging/wlan-ng/p80211mgmt.h | 8 ++++----
drivers/staging/wlan-ng/p80211types.h | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/wlan-ng/p80211mgmt.h b/drivers/staging/wlan-ng/p80211mgmt.h
index 1ef30d3f3159..d6fe52de2c8f 100644
--- a/drivers/staging/wlan-ng/p80211mgmt.h
+++ b/drivers/staging/wlan-ng/p80211mgmt.h
@@ -229,14 +229,14 @@ struct wlan_ie {
struct wlan_ie_ssid {
u8 eid;
u8 len;
- u8 ssid[1]; /* may be zero, ptrs may overlap */
+ u8 ssid[]; /* may be zero, ptrs may overlap */
} __packed;

/*-- Supported Rates -----------------------------*/
struct wlan_ie_supp_rates {
u8 eid;
u8 len;
- u8 rates[1]; /* had better be at LEAST one! */
+ u8 rates[]; /* had better be at LEAST one! */
} __packed;

/*-- FH Parameter Set ----------------------------*/
@@ -274,7 +274,7 @@ struct wlan_ie_tim {
u8 dtim_cnt;
u8 dtim_period;
u8 bitmap_ctl;
- u8 virt_bm[1];
+ u8 virt_bm[];
} __packed;

/*-- IBSS Parameter Set ---------------------------*/
@@ -288,7 +288,7 @@ struct wlan_ie_ibss_parms {
struct wlan_ie_challenge {
u8 eid;
u8 len;
- u8 challenge[1];
+ u8 challenge[];
} __packed;

/*-------------------------------------------------*/
diff --git a/drivers/staging/wlan-ng/p80211types.h b/drivers/staging/wlan-ng/p80211types.h
index 6486612a8f31..b2ffd09881b0 100644
--- a/drivers/staging/wlan-ng/p80211types.h
+++ b/drivers/staging/wlan-ng/p80211types.h
@@ -234,7 +234,7 @@ struct p80211pstr32 {
/* MAC address array */
struct p80211macarray {
u32 cnt;
- u8 data[1][MAXLEN_PSTR6];
+ u8 data[][MAXLEN_PSTR6];
} __packed;

/* prototype template */
--
2.34.1





2022-10-28 15:07:24

by Deepak R Varma

[permalink] [raw]
Subject: Re: [PATCH] staging: wlan-ng: Use flexible-array for one / zero-length arrays

On Fri, Oct 28, 2022 at 05:36:41PM +0300, Dan Carpenter wrote:
> On Fri, Oct 28, 2022 at 06:08:13PM +0530, Deepak R Varma wrote:
> > Flexible-array member should be used instead of one or zero member to
> > meet the need for having a dynamically sized trailing elements in a
> > structure. Refer to links [1] and [2] for detailed guidance on this
> > suggestion.
> >
> > [1] https://en.wikipedia.org/wiki/Flexible_array_member
> > [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
> >
> > Issue identified using coccicheck.
> >
> > Signed-off-by: Deepak R Varma <[email protected]>
> > ---
> > drivers/staging/wlan-ng/p80211mgmt.h | 8 ++++----
> > drivers/staging/wlan-ng/p80211types.h | 2 +-
> > 2 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/staging/wlan-ng/p80211mgmt.h b/drivers/staging/wlan-ng/p80211mgmt.h
> > index 1ef30d3f3159..d6fe52de2c8f 100644
> > --- a/drivers/staging/wlan-ng/p80211mgmt.h
> > +++ b/drivers/staging/wlan-ng/p80211mgmt.h
> > @@ -229,14 +229,14 @@ struct wlan_ie {
> > struct wlan_ie_ssid {
> > u8 eid;
> > u8 len;
> > - u8 ssid[1]; /* may be zero, ptrs may overlap */
> > + u8 ssid[]; /* may be zero, ptrs may overlap */
> > } __packed;
>
> When you're writing this change look at where struct wlan_ie_ssid is
> used. It's included in five different structs:
>
> struct wlan_ie_ssid *ssid;
>
> But none of those *ssid pointers are used. So instead of doing this
> just delete the wlan_ie_ssid struct and delete every reference to it.
> Send that as a patch by itself and then repeat that process for the next
> struct.

Thank you Dan. I had the same observation, but was not sure if that clean up
should be included as part of current patch scope. Now I will, as you advised.

Also, there are a few function declarations that I do not think are used in the
code anywhere.
File: drivers/staging/wlan-ng/p80211mgmt.h
Line number : 500 through 519

Can you please comment if it is safe to remove these functions and include this
clean-up as well in the proposed patch?

Thank you,
./drv

>
> regards,
> dan carpenter
>



2022-10-28 15:17:54

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] staging: wlan-ng: Use flexible-array for one / zero-length arrays

On Fri, Oct 28, 2022 at 06:08:13PM +0530, Deepak R Varma wrote:
> Flexible-array member should be used instead of one or zero member to
> meet the need for having a dynamically sized trailing elements in a
> structure. Refer to links [1] and [2] for detailed guidance on this
> suggestion.
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
>
> Issue identified using coccicheck.
>
> Signed-off-by: Deepak R Varma <[email protected]>
> ---
> drivers/staging/wlan-ng/p80211mgmt.h | 8 ++++----
> drivers/staging/wlan-ng/p80211types.h | 2 +-
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/wlan-ng/p80211mgmt.h b/drivers/staging/wlan-ng/p80211mgmt.h
> index 1ef30d3f3159..d6fe52de2c8f 100644
> --- a/drivers/staging/wlan-ng/p80211mgmt.h
> +++ b/drivers/staging/wlan-ng/p80211mgmt.h
> @@ -229,14 +229,14 @@ struct wlan_ie {
> struct wlan_ie_ssid {
> u8 eid;
> u8 len;
> - u8 ssid[1]; /* may be zero, ptrs may overlap */
> + u8 ssid[]; /* may be zero, ptrs may overlap */
> } __packed;

When you're writing this change look at where struct wlan_ie_ssid is
used. It's included in five different structs:

struct wlan_ie_ssid *ssid;

But none of those *ssid pointers are used. So instead of doing this
just delete the wlan_ie_ssid struct and delete every reference to it.
Send that as a patch by itself and then repeat that process for the next
struct.

regards,
dan carpenter


2022-10-28 15:20:09

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] staging: wlan-ng: Use flexible-array for one / zero-length arrays

On Fri, Oct 28, 2022 at 08:14:53PM +0530, Deepak R Varma wrote:
> Also, there are a few function declarations that I do not think are used in the
> code anywhere.
> File: drivers/staging/wlan-ng/p80211mgmt.h
> Line number : 500 through 519
>
> Can you please comment if it is safe to remove these functions and include this
> clean-up as well in the proposed patch?

Always feel free to delete code that is not used.

(But send the patch tomorrow and as part of a patchset).

regards,
dan carpenter



2022-11-01 14:06:40

by Deepak R Varma

[permalink] [raw]
Subject: Re: [PATCH] staging: wlan-ng: Use flexible-array for one / zero-length arrays

On Fri, Oct 28, 2022 at 05:36:41PM +0300, Dan Carpenter wrote:
> On Fri, Oct 28, 2022 at 06:08:13PM +0530, Deepak R Varma wrote:
> > Flexible-array member should be used instead of one or zero member to
> > meet the need for having a dynamically sized trailing elements in a
> > structure. Refer to links [1] and [2] for detailed guidance on this
> > suggestion.
> >
> > [1] https://en.wikipedia.org/wiki/Flexible_array_member
> > [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
> >
> > Issue identified using coccicheck.
> >
> > Signed-off-by: Deepak R Varma <[email protected]>
> > ---
> > drivers/staging/wlan-ng/p80211mgmt.h | 8 ++++----
> > drivers/staging/wlan-ng/p80211types.h | 2 +-
> > 2 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/staging/wlan-ng/p80211mgmt.h b/drivers/staging/wlan-ng/p80211mgmt.h
> > index 1ef30d3f3159..d6fe52de2c8f 100644
> > --- a/drivers/staging/wlan-ng/p80211mgmt.h
> > +++ b/drivers/staging/wlan-ng/p80211mgmt.h
> > @@ -229,14 +229,14 @@ struct wlan_ie {
> > struct wlan_ie_ssid {
> > u8 eid;
> > u8 len;
> > - u8 ssid[1]; /* may be zero, ptrs may overlap */
> > + u8 ssid[]; /* may be zero, ptrs may overlap */
> > } __packed;
>
> When you're writing this change look at where struct wlan_ie_ssid is
> used. It's included in five different structs:
>
> struct wlan_ie_ssid *ssid;
>
> But none of those *ssid pointers are used. So instead of doing this
> just delete the wlan_ie_ssid struct and delete every reference to it.
> Send that as a patch by itself and then repeat that process for the next
> struct.

Hello Dan and Pavel,
I have built a patch set based on your feedback on this (and the other similar
patch for r8188eu driver). I have only covered one driver for now and would wait
for feedback before I do the same thing for the other driver.

Thank you,
./drv

>
> regards,
> dan carpenter
>