2022-11-18 21:12:26

by Kees Cook

Subject: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

Zero-length arrays are deprecated[1] and are being replaced with
flexible array members in support of the ongoing efforts to tighten the
FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.

Replace zero-length array with flexible-array member.

This results in no differences in binary output.

[1] https://github.com/KSPP/linux/issues/78

Cc: Christian Lamparter <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: "Gustavo A. R. Silva" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/net/wireless/ath/carl9170/fwcmd.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/carl9170/fwcmd.h b/drivers/net/wireless/ath/carl9170/fwcmd.h
index 4a500095555c..ff4b3b50250c 100644
--- a/drivers/net/wireless/ath/carl9170/fwcmd.h
+++ b/drivers/net/wireless/ath/carl9170/fwcmd.h
@@ -118,10 +118,10 @@ struct carl9170_reg_list {
} __packed;

struct carl9170_write_reg {
- struct {
+ DECLARE_FLEX_ARRAY(struct {
__le32 addr;
__le32 val;
- } regs[0] __packed;
+ } __packed, regs);
} __packed;

struct carl9170_write_reg_byte {
--
2.34.1

2022-11-18 22:39:12

by Gustavo A. R. Silva

Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

On Fri, Nov 18, 2022 at 01:11:47PM -0800, Kees Cook wrote:
> Zero-length arrays are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
>
> Replace zero-length array with flexible-array member.
>
> This results in no differences in binary output.
>
> [1] https://github.com/KSPP/linux/issues/78
>
> Cc: Christian Lamparter <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Another sneaky one. :p

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks!
--
Gustavo

> ---
> drivers/net/wireless/ath/carl9170/fwcmd.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/carl9170/fwcmd.h b/drivers/net/wireless/ath/carl9170/fwcmd.h
> index 4a500095555c..ff4b3b50250c 100644
> --- a/drivers/net/wireless/ath/carl9170/fwcmd.h
> +++ b/drivers/net/wireless/ath/carl9170/fwcmd.h
> @@ -118,10 +118,10 @@ struct carl9170_reg_list {
> } __packed;
>
> struct carl9170_write_reg {
> - struct {
> + DECLARE_FLEX_ARRAY(struct {
> __le32 addr;
> __le32 val;
> - } regs[0] __packed;
> + } __packed, regs);
> } __packed;
>
> struct carl9170_write_reg_byte {
> --
> 2.34.1
>

2022-11-18 23:21:35

by Christian Lamparter

Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

On 11/18/22 22:11, Kees Cook wrote:
> Zero-length arrays are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
>
> Replace zero-length array with flexible-array member.
>
> This results in no differences in binary output.
>
> [1] https://github.com/KSPP/linux/issues/78
>
> Cc: Christian Lamparter <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
Acked-by: Christian Lamparter <[email protected]>

> ---
> drivers/net/wireless/ath/carl9170/fwcmd.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/carl9170/fwcmd.h b/drivers/net/wireless/ath/carl9170/fwcmd.h
> index 4a500095555c..ff4b3b50250c 100644
> --- a/drivers/net/wireless/ath/carl9170/fwcmd.h
> +++ b/drivers/net/wireless/ath/carl9170/fwcmd.h
> @@ -118,10 +118,10 @@ struct carl9170_reg_list {
> } __packed;
>
> struct carl9170_write_reg {
> - struct {
> + DECLARE_FLEX_ARRAY(struct {
> __le32 addr;
> __le32 val;
> - } regs[0] __packed;
> + } __packed, regs);
> } __packed;
>
> struct carl9170_write_reg_byte {

2022-11-19 06:39:47

by Kalle Valo

Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

Kees Cook <[email protected]> writes:

> Zero-length arrays are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
>
> Replace zero-length array with flexible-array member.
>
> This results in no differences in binary output.
>
> [1] https://github.com/KSPP/linux/issues/78
>
> Cc: Christian Lamparter <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Nowadays we include "wifi:" in the subject, but I can add that. But
please use this in the future for all wireless patches.

--
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

2022-11-19 07:18:20

by Kees Cook

Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

On Sat, Nov 19, 2022 at 08:39:11AM +0200, Kalle Valo wrote:
> Kees Cook <[email protected]> writes:
>
> > Zero-length arrays are deprecated[1] and are being replaced with
> > flexible array members in support of the ongoing efforts to tighten the
> > FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> > with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
> >
> > Replace zero-length array with flexible-array member.
> >
> > This results in no differences in binary output.
> >
> > [1] https://github.com/KSPP/linux/issues/78
> >
> > Cc: Christian Lamparter <[email protected]>
> > Cc: Kalle Valo <[email protected]>
> > Cc: "David S. Miller" <[email protected]>
> > Cc: Eric Dumazet <[email protected]>
> > Cc: Jakub Kicinski <[email protected]>
> > Cc: Paolo Abeni <[email protected]>
> > Cc: "Gustavo A. R. Silva" <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Kees Cook <[email protected]>
>
> Nowadays we include "wifi:" in the subject, but I can add that. But
> please use this in the future for all wireless patches.

Okay, thanks! I use a recency/frequency prefix guesser, but I've updated
it to include "wifi: " if "[email protected]" is in CC. :)

--
Kees Cook

2022-11-25 11:24:42

by Kalle Valo

Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

Kees Cook <[email protected]> wrote:

> Zero-length arrays are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
>
> Replace zero-length array with flexible-array member.
>
> This results in no differences in binary output.
>
> [1] https://github.com/KSPP/linux/issues/78
>
> Cc: Christian Lamparter <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Eric Dumazet <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Paolo Abeni <[email protected]>
> Cc: "Gustavo A. R. Silva" <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
> Reviewed-by: Gustavo A. R. Silva <[email protected]>
> Acked-by: Christian Lamparter <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

7256f28767fa wifi: carl9170: Replace zero-length array of trailing structs with flex-array

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches