* [PATCH 0/2] wifi: ath: false-positive fortified-memset warnings
@ 2024-03-28 13:55 Arnd Bergmann
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
2024-03-28 13:55 ` [PATCH 2/2] wifi: ath9k: work around memset overflow warning Arnd Bergmann
0 siblings, 2 replies; 8+ messages in thread
From: Arnd Bergmann @ 2024-03-28 13:55 UTC (permalink / raw)
To: Kees Cook
Cc: linux-hardening, Toke Høiland-Jørgensen,
linux-wireless, Kalle Valo, Arnd Bergmann
From: Arnd Bergmann <arnd@arndb.de>
While testing some other patch series I worked on across gcc versions, I found
a couple of stringop warnings that only show up with some toolchains but not
others. The warnings I both seem to be false positive.
I have also not found an explanation why both of these happen in atheros
wireless drivers, as I don't see this in other drivers.
Maybe Kees can work out what is going on here.
Arnd Bergmann (2):
[RESEND] carl9170: re-fix fortified-memset warning
ath9k: work around memset overflow warning
drivers/net/wireless/ath/ath.h | 6 ++++--
drivers/net/wireless/ath/ath9k/main.c | 3 +--
drivers/net/wireless/ath/carl9170/tx.c | 3 ++-
3 files changed, 7 insertions(+), 5 deletions(-)
--
2.39.2
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning
2024-03-28 13:55 [PATCH 0/2] wifi: ath: false-positive fortified-memset warnings Arnd Bergmann
@ 2024-03-28 13:55 ` Arnd Bergmann
2024-03-28 21:51 ` Kees Cook
` (2 more replies)
2024-03-28 13:55 ` [PATCH 2/2] wifi: ath9k: work around memset overflow warning Arnd Bergmann
1 sibling, 3 replies; 8+ messages in thread
From: Arnd Bergmann @ 2024-03-28 13:55 UTC (permalink / raw)
To: Kees Cook, Christian Lamparter, Kalle Valo, Johannes Berg
Cc: linux-hardening, Toke Høiland-Jørgensen,
linux-wireless, Arnd Bergmann, Colin Ian King, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
The carl9170_tx_release() function sometimes triggers a fortified-memset
warning in my randconfig builds:
In file included from include/linux/string.h:254,
from drivers/net/wireless/ath/carl9170/tx.c:40:
In function 'fortify_memset_chk',
inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2,
inlined from 'kref_put' at include/linux/kref.h:65:3,
inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9:
include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
493 | __write_overflow_field(p_size_field, size);
Kees previously tried to avoid this by using memset_after(), but it seems
this does not fully address the problem. I noticed that the memset_after()
here is done on a different part of the union (status) than the original
cast was from (rate_driver_data), which may confuse the compiler.
Unfortunately, the memset_after() trick does not work on driver_rates[]
because that is part of an anonymous struct, and I could not get
struct_group() to do this either. Using two separate memset() calls
on the two members does address the warning though.
Fixes: fb5f6a0e8063b ("mac80211: Use memset_after() to clear tx status")
Link: https://lore.kernel.org/lkml/20230623152443.2296825-1-arnd@kernel.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I found this while testing randconfig builds, a .config that shows this
for me is at https://pastebin.com/yWFKvZYu
Sorry I failed to follow up to Kees' request for a reproducer when
I posted this last year.
---
drivers/net/wireless/ath/carl9170/tx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
index e902ca80eba7..0226c31a6cae 100644
--- a/drivers/net/wireless/ath/carl9170/tx.c
+++ b/drivers/net/wireless/ath/carl9170/tx.c
@@ -280,7 +280,8 @@ static void carl9170_tx_release(struct kref *ref)
* carl9170_tx_fill_rateinfo() has filled the rate information
* before we get to this point.
*/
- memset_after(&txinfo->status, 0, rates);
+ memset(&txinfo->pad, 0, sizeof(txinfo->pad));
+ memset(&txinfo->rate_driver_data, 0, sizeof(txinfo->rate_driver_data));
if (atomic_read(&ar->tx_total_queued))
ar->tx_schedule = true;
--
2.39.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/2] wifi: ath9k: work around memset overflow warning
2024-03-28 13:55 [PATCH 0/2] wifi: ath: false-positive fortified-memset warnings Arnd Bergmann
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
@ 2024-03-28 13:55 ` Arnd Bergmann
2024-03-28 21:14 ` Toke Høiland-Jørgensen
2024-03-28 21:50 ` Kees Cook
1 sibling, 2 replies; 8+ messages in thread
From: Arnd Bergmann @ 2024-03-28 13:55 UTC (permalink / raw)
To: Kees Cook, Kalle Valo, Toke Høiland-Jørgensen
Cc: linux-hardening, linux-wireless, Arnd Bergmann, Jeff Johnson,
Dmitry Antipov, Hancheng Yang, Remi Pommarel, Johannes Berg,
linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
gcc-9 and some other older versions produce a false-positive warning
for zeroing two fields
In file included from include/linux/string.h:369,
from drivers/net/wireless/ath/ath9k/main.c:18:
In function 'fortify_memset_chk',
inlined from 'ath9k_ps_wakeup' at drivers/net/wireless/ath/ath9k/main.c:140:3:
include/linux/fortify-string.h:462:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
462 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using a struct_group seems to reliably avoid the warning and
not make the code much uglier. The combined memset() should even
save a couple of cpu cycles.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
This is from randconfig testing, see https://pastebin.com/yjKk5N81
for a reproducer
---
drivers/net/wireless/ath/ath.h | 6 ++++--
drivers/net/wireless/ath/ath9k/main.c | 3 +--
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index f02a308a9ffc..34654f710d8a 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -171,8 +171,10 @@ struct ath_common {
unsigned int clockrate;
spinlock_t cc_lock;
- struct ath_cycle_counters cc_ani;
- struct ath_cycle_counters cc_survey;
+ struct_group(cc,
+ struct ath_cycle_counters cc_ani;
+ struct ath_cycle_counters cc_survey;
+ );
struct ath_regulatory regulatory;
struct ath_regulatory reg_world_copy;
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index a2943aaecb20..01173aac3045 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -135,8 +135,7 @@ void ath9k_ps_wakeup(struct ath_softc *sc)
if (power_mode != ATH9K_PM_AWAKE) {
spin_lock(&common->cc_lock);
ath_hw_cycle_counters_update(common);
- memset(&common->cc_survey, 0, sizeof(common->cc_survey));
- memset(&common->cc_ani, 0, sizeof(common->cc_ani));
+ memset(&common->cc, 0, sizeof(common->cc));
spin_unlock(&common->cc_lock);
}
--
2.39.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 2/2] wifi: ath9k: work around memset overflow warning
2024-03-28 13:55 ` [PATCH 2/2] wifi: ath9k: work around memset overflow warning Arnd Bergmann
@ 2024-03-28 21:14 ` Toke Høiland-Jørgensen
2024-03-28 21:50 ` Kees Cook
1 sibling, 0 replies; 8+ messages in thread
From: Toke Høiland-Jørgensen @ 2024-03-28 21:14 UTC (permalink / raw)
To: Arnd Bergmann, Kees Cook, Kalle Valo
Cc: linux-hardening, linux-wireless, Arnd Bergmann, Jeff Johnson,
Dmitry Antipov, Hancheng Yang, Remi Pommarel, Johannes Berg,
linux-kernel
Arnd Bergmann <arnd@kernel.org> writes:
> From: Arnd Bergmann <arnd@arndb.de>
>
> gcc-9 and some other older versions produce a false-positive warning
> for zeroing two fields
>
> In file included from include/linux/string.h:369,
> from drivers/net/wireless/ath/ath9k/main.c:18:
> In function 'fortify_memset_chk',
> inlined from 'ath9k_ps_wakeup' at drivers/net/wireless/ath/ath9k/main.c:140:3:
> include/linux/fortify-string.h:462:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 462 | __write_overflow_field(p_size_field, size);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Using a struct_group seems to reliably avoid the warning and
> not make the code much uglier. The combined memset() should even
> save a couple of cpu cycles.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/2] wifi: ath9k: work around memset overflow warning
2024-03-28 13:55 ` [PATCH 2/2] wifi: ath9k: work around memset overflow warning Arnd Bergmann
2024-03-28 21:14 ` Toke Høiland-Jørgensen
@ 2024-03-28 21:50 ` Kees Cook
1 sibling, 0 replies; 8+ messages in thread
From: Kees Cook @ 2024-03-28 21:50 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Kalle Valo, Toke Høiland-Jørgensen, linux-hardening,
linux-wireless, Arnd Bergmann, Jeff Johnson, Dmitry Antipov,
Hancheng Yang, Remi Pommarel, Johannes Berg, linux-kernel
On Thu, Mar 28, 2024 at 02:55:05PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> gcc-9 and some other older versions produce a false-positive warning
> for zeroing two fields
>
> In file included from include/linux/string.h:369,
> from drivers/net/wireless/ath/ath9k/main.c:18:
> In function 'fortify_memset_chk',
> inlined from 'ath9k_ps_wakeup' at drivers/net/wireless/ath/ath9k/main.c:140:3:
> include/linux/fortify-string.h:462:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 462 | __write_overflow_field(p_size_field, size);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Using a struct_group seems to reliably avoid the warning and
> not make the code much uglier. The combined memset() should even
> save a couple of cpu cycles.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
@ 2024-03-28 21:51 ` Kees Cook
2024-03-29 12:56 ` Christian Lamparter
2024-04-04 10:10 ` Kalle Valo
2 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2024-03-28 21:51 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Christian Lamparter, Kalle Valo, Johannes Berg, linux-hardening,
Toke Høiland-Jørgensen, linux-wireless, Arnd Bergmann,
Colin Ian King, linux-kernel
On Thu, Mar 28, 2024 at 02:55:04PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The carl9170_tx_release() function sometimes triggers a fortified-memset
> warning in my randconfig builds:
>
> In file included from include/linux/string.h:254,
> from drivers/net/wireless/ath/carl9170/tx.c:40:
> In function 'fortify_memset_chk',
> inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2,
> inlined from 'kref_put' at include/linux/kref.h:65:3,
> inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9:
> include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 493 | __write_overflow_field(p_size_field, size);
>
> Kees previously tried to avoid this by using memset_after(), but it seems
> this does not fully address the problem. I noticed that the memset_after()
> here is done on a different part of the union (status) than the original
> cast was from (rate_driver_data), which may confuse the compiler.
>
> Unfortunately, the memset_after() trick does not work on driver_rates[]
> because that is part of an anonymous struct, and I could not get
> struct_group() to do this either. Using two separate memset() calls
> on the two members does address the warning though.
>
> Fixes: fb5f6a0e8063b ("mac80211: Use memset_after() to clear tx status")
> Link: https://lore.kernel.org/lkml/20230623152443.2296825-1-arnd@kernel.org/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
2024-03-28 21:51 ` Kees Cook
@ 2024-03-29 12:56 ` Christian Lamparter
2024-04-04 10:10 ` Kalle Valo
2 siblings, 0 replies; 8+ messages in thread
From: Christian Lamparter @ 2024-03-29 12:56 UTC (permalink / raw)
To: Arnd Bergmann, Kees Cook, Kalle Valo, Johannes Berg
Cc: linux-hardening, Toke Høiland-Jørgensen,
linux-wireless, Arnd Bergmann, Colin Ian King, linux-kernel
On 3/28/24 2:55 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The carl9170_tx_release() function sometimes triggers a fortified-memset
> warning in my randconfig builds:
>
> In file included from include/linux/string.h:254,
> from drivers/net/wireless/ath/carl9170/tx.c:40:
> In function 'fortify_memset_chk',
> inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2,
> inlined from 'kref_put' at include/linux/kref.h:65:3,
> inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9:
> include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 493 | __write_overflow_field(p_size_field, size);
>
> Kees previously tried to avoid this by using memset_after(), but it seems
> this does not fully address the problem. I noticed that the memset_after()
> here is done on a different part of the union (status) than the original
> cast was from (rate_driver_data), which may confuse the compiler.
>
> Unfortunately, the memset_after() trick does not work on driver_rates[]
> because that is part of an anonymous struct, and I could not get
> struct_group() to do this either. Using two separate memset() calls
> on the two members does address the warning though.
>
> Fixes: fb5f6a0e8063b ("mac80211: Use memset_after() to clear tx status")
> Link: https://lore.kernel.org/lkml/20230623152443.2296825-1-arnd@kernel.org/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Sure... though I think AI-supported compilers will in the future nag about
this again. Oh well!
Acked-by: Christian Lamparter <chunkeey@gmail.com>
> ---
> I found this while testing randconfig builds, a .config that shows this
> for me is at https://pastebin.com/yWFKvZYu
>
> Sorry I failed to follow up to Kees' request for a reproducer when
> I posted this last year.
> ---
> drivers/net/wireless/ath/carl9170/tx.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
> index e902ca80eba7..0226c31a6cae 100644
> --- a/drivers/net/wireless/ath/carl9170/tx.c
> +++ b/drivers/net/wireless/ath/carl9170/tx.c
> @@ -280,7 +280,8 @@ static void carl9170_tx_release(struct kref *ref)
> * carl9170_tx_fill_rateinfo() has filled the rate information
> * before we get to this point.
> */
> - memset_after(&txinfo->status, 0, rates);
> + memset(&txinfo->pad, 0, sizeof(txinfo->pad));
> + memset(&txinfo->rate_driver_data, 0, sizeof(txinfo->rate_driver_data));
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
2024-03-28 21:51 ` Kees Cook
2024-03-29 12:56 ` Christian Lamparter
@ 2024-04-04 10:10 ` Kalle Valo
2 siblings, 0 replies; 8+ messages in thread
From: Kalle Valo @ 2024-04-04 10:10 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Kees Cook, Christian Lamparter, Johannes Berg, linux-hardening,
Toke Høiland-Jørgensen, linux-wireless, Arnd Bergmann,
Colin Ian King, linux-kernel
Arnd Bergmann <arnd@kernel.org> wrote:
> The carl9170_tx_release() function sometimes triggers a fortified-memset
> warning in my randconfig builds:
>
> In file included from include/linux/string.h:254,
> from drivers/net/wireless/ath/carl9170/tx.c:40:
> In function 'fortify_memset_chk',
> inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2,
> inlined from 'kref_put' at include/linux/kref.h:65:3,
> inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9:
> include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
> 493 | __write_overflow_field(p_size_field, size);
>
> Kees previously tried to avoid this by using memset_after(), but it seems
> this does not fully address the problem. I noticed that the memset_after()
> here is done on a different part of the union (status) than the original
> cast was from (rate_driver_data), which may confuse the compiler.
>
> Unfortunately, the memset_after() trick does not work on driver_rates[]
> because that is part of an anonymous struct, and I could not get
> struct_group() to do this either. Using two separate memset() calls
> on the two members does address the warning though.
>
> Fixes: fb5f6a0e8063b ("mac80211: Use memset_after() to clear tx status")
> Link: https://lore.kernel.org/lkml/20230623152443.2296825-1-arnd@kernel.org/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Acked-by: Christian Lamparter <chunkeey@gmail.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
2 patches applied to ath-next branch of ath.git, thanks.
066afafc10c9 wifi: carl9170: re-fix fortified-memset warning
61752ac69b69 wifi: ath9k: work around memset overflow warning
--
https://patchwork.kernel.org/project/linux-wireless/patch/20240328135509.3755090-2-arnd@kernel.org/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2024-04-04 10:10 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-03-28 13:55 [PATCH 0/2] wifi: ath: false-positive fortified-memset warnings Arnd Bergmann
2024-03-28 13:55 ` [PATCH 1/2] [RESEND] wifi: carl9170: re-fix fortified-memset warning Arnd Bergmann
2024-03-28 21:51 ` Kees Cook
2024-03-29 12:56 ` Christian Lamparter
2024-04-04 10:10 ` Kalle Valo
2024-03-28 13:55 ` [PATCH 2/2] wifi: ath9k: work around memset overflow warning Arnd Bergmann
2024-03-28 21:14 ` Toke Høiland-Jørgensen
2024-03-28 21:50 ` Kees Cook
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