2021-05-21 09:26:40

by Yiyuan guo

[permalink] [raw]
Subject: [PATCH] mwifiex: protect against divide by zero in mwifiex_set_ibss_params

In function mwifiex_set_ibss_params, the variable index may remain
zero if it is never altered inside the loop, leading to a potential
divide by zero problem.

Signed-off-by: Yiyuan GUO <[email protected]>
---
drivers/net/wireless/marvell/mwifiex/cfg80211.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 0961f4a5e..afcdebdcf 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -2450,7 +2450,7 @@ static int mwifiex_set_ibss_params(struct mwifiex_private *priv,
config_bands = BAND_B;
} else {
config_bands = BAND_G;
- if (params->basic_rates % index)
+ if (index && (params->basic_rates % index))
config_bands |= BAND_B;
}
}
--
2.25.1


2021-06-15 13:34:40

by Kalle Valo

[permalink] [raw]
Subject: Re: [PATCH] mwifiex: protect against divide by zero in mwifiex_set_ibss_params

Yiyuan GUO <[email protected]> wrote:

> In function mwifiex_set_ibss_params, the variable index may remain
> zero if it is never altered inside the loop, leading to a potential
> divide by zero problem.
>
> Signed-off-by: Yiyuan GUO <[email protected]>

Brian explains in the report why the code is ok:
https://bugzilla.kernel.org/show_bug.cgi?id=212993#c1

Patch set to Rejected.

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

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

2021-06-15 17:19:05

by Brian Norris

[permalink] [raw]
Subject: Re: [PATCH] mwifiex: protect against divide by zero in mwifiex_set_ibss_params

On Tue, Jun 15, 2021 at 6:31 AM Kalle Valo <[email protected]> wrote:
>
> Yiyuan GUO <[email protected]> wrote:
>
> > In function mwifiex_set_ibss_params, the variable index may remain
> > zero if it is never altered inside the loop, leading to a potential
> > divide by zero problem.
> >
> > Signed-off-by: Yiyuan GUO <[email protected]>
>
> Brian explains in the report why the code is ok:
> https://bugzilla.kernel.org/show_bug.cgi?id=212993#c1

Ah, forgot there was a patch for this too. FWIW, it's probably ok to
submit such a patch, if just for safety's sake (future refactoring?).
I just didn't figure it deserved an open "bug" entry, when it's
clearly not one.

> Patch set to Rejected.

That's fine with me.

Thanks,
Brian