Re: [PATCH wireless] wifi: wilc1000: fix ies_len type in connect path

[Ajay.Kathat]

On 7/1/24 09:23, Alexis Lothoré wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> From: Jozef Hopko <jozef.hopko@xxxxxxxxxx>
> 
> Commit 205c50306acf ("wifi: wilc1000: fix RCU usage in connect path")
> made sure that the IEs data was manipulated under the relevant RCU section.
> Unfortunately, while doing so, the commit brought a faulty implicit cast
> from int to u8 on the ies_len variable, making the parsing fail to be
> performed correctly if the IEs block is larger than 255 bytes. This failure
> can be observed with Access Points appending a lot of IEs TLVs in their
> beacon frames (reproduced with a Pixel phone acting as an Access Point,
> which brough 273 bytes of IE data in my testing environment).
> 
> Fix IEs parsing by removing this undesired implicit cast.
> 
> Fixes: 205c50306acf ("wifi: wilc1000: fix RCU usage in connect path")
> Signed-off-by: Jozef Hopko <jozef.hopko@xxxxxxxxxx>
> Signed-off-by: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx>

Thanks Jozef Hopko & Alexis.

Acked-by: Ajay Singh <ajay.kathat@xxxxxxxxxxxxx>

> ---
> The issue has been initially detected by Jozef Hopko, and the resulting
> patch is also from him. He asked me to upstream it on his behalf. I have
> successfuly reproduced the same issue and confirmed that the patch indeed
> fixes the connection to the AP I used. The only update I did is about
> adding details about the issue in commit message and fixing whitespaces.
> The issue has been disclosed to me directly through private mail, so I have
> no relevant Reported-By/Closes tag to provide. I am not sure however why I
> do not manage to make sparse detect this faulty cast.
> ---
>  drivers/net/wireless/microchip/wilc1000/hif.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/microchip/wilc1000/hif.c b/drivers/net/wireless/microchip/wilc1000/hif.c
> index d67293142ffb..3c48e1a57b24 100644
> --- a/drivers/net/wireless/microchip/wilc1000/hif.c
> +++ b/drivers/net/wireless/microchip/wilc1000/hif.c
> @@ -382,7 +382,8 @@ wilc_parse_join_bss_param(struct cfg80211_bss *bss,
>         struct ieee80211_p2p_noa_attr noa_attr;
>         const struct cfg80211_bss_ies *ies;
>         struct wilc_join_bss_param *param;
> -       u8 rates_len = 0, ies_len;
> +       u8 rates_len = 0;
> +       int ies_len;
>         int ret;
> 
>         param = kzalloc(sizeof(*param), GFP_KERNEL);
> 
> ---
> base-commit: 21cfb73516c112f0cf0d3ebd3e4bdfbadc819576
> change-id: 20240701-wilc_fix_ies_data-22226322ee7c
> 
> Best regards,
> --
> Alexis Lothoré, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>