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Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage

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  Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage Nicolas Iooss <nicolas.iooss_linux@m4x.org> - 2016-08-22 15:10 +0200
    Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage Rafał Miłecki <zajec5@gmail.com> - 2016-08-22 15:20 +0200
    Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage Arend Van Spriel <arend.vanspriel@broadcom.com> - 2016-08-22 21:40 +0200
      Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage Nicolas Iooss <nicolas.iooss_linux@m4x.org> - 2016-08-23 11:40 +0200
        [PATCH v2 1/1] brcmfmac: fix pmksa->bssid usage Nicolas Iooss <nicolas.iooss_linux@m4x.org> - 2016-08-23 11:50 +0200

#1467609 — Re: [PATCH 1/1] brcmfmac: fix pmksa->bssid usage

Hello,

After I sent the following patch a few weeks ago, I have not received
any feedback. Could you please review it and tell me what I may have
done wrong?

Thanks,
Nicolas

On 05/08/16 22:34, Nicolas Iooss wrote:
> The struct cfg80211_pmksa defines its bssid field as:
> 
>     const u8 *bssid;
> 
> contrary to struct brcmf_pmksa, which uses:
> 
>     u8 bssid[ETH_ALEN];
> 
> Therefore in brcmf_cfg80211_del_pmksa(), &pmksa->bssid takes the address
> of this field (of type u8**), not the one of its content (which would be
> u8*).  Remove the & operator to make brcmf_dbg("%pM") and memcmp()
> behave as expected.
> 
> This bug have been found using a custom static checker (which checks the
> usage of %p... attributes at build time).  It has been introduced in
> commit 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code"),
> which replaced pmksa->bssid by &pmksa->bssid while refactoring the code,
> without modifying struct cfg80211_pmksa definition.
> 
> Fixes: 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code")
> Cc: stable@ger.kernel.org
> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
> ---
> 
> scripts/checkpatch.pl reports a warning: "Prefer ether_addr_equal() or
> ether_addr_equal_unaligned() over memcmp()".  Because some files in
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/ still use memcmp()
> to compare addresses and because I do not know whether pmksa->bssid is
> always aligned, I did not follow this warning.
> 
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> index 2628d5e12c64..aceab77cd95a 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> @@ -3884,11 +3884,11 @@ brcmf_cfg80211_del_pmksa(struct wiphy *wiphy, struct net_device *ndev,
>  	if (!check_vif_up(ifp->vif))
>  		return -EIO;
>  
> -	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", &pmksa->bssid);
> +	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", pmksa->bssid);
>  
>  	npmk = le32_to_cpu(cfg->pmk_list.npmk);
>  	for (i = 0; i < npmk; i++)
> -		if (!memcmp(&pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
> +		if (!memcmp(pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
>  			break;
>  
>  	if ((npmk > 0) && (i < npmk)) {
> 

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#1467618

On 22 August 2016 at 15:03, Nicolas Iooss <nicolas.iooss_linux@m4x.org> wrote:
> After I sent the following patch a few weeks ago, I have not received
> any feedback. Could you please review it and tell me what I may have
> done wrong?

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches#checking_state_of_patches_from_patchwork
https://patchwork.kernel.org/patch/9265733/

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#1467994

On 22-8-2016 15:03, Nicolas Iooss wrote:
> Hello,
> 
> After I sent the following patch a few weeks ago, I have not received
> any feedback. Could you please review it and tell me what I may have
> done wrong?

Nothing. People went on vacation :-)
> Thanks,
> Nicolas
> 
> On 05/08/16 22:34, Nicolas Iooss wrote:
>> The struct cfg80211_pmksa defines its bssid field as:
>>
>>     const u8 *bssid;
>>
>> contrary to struct brcmf_pmksa, which uses:
>>
>>     u8 bssid[ETH_ALEN];
>>
>> Therefore in brcmf_cfg80211_del_pmksa(), &pmksa->bssid takes the address
>> of this field (of type u8**), not the one of its content (which would be
>> u8*).  Remove the & operator to make brcmf_dbg("%pM") and memcmp()
>> behave as expected.
>>
>> This bug have been found using a custom static checker (which checks the
>> usage of %p... attributes at build time).  It has been introduced in
>> commit 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code"),
>> which replaced pmksa->bssid by &pmksa->bssid while refactoring the code,
>> without modifying struct cfg80211_pmksa definition.
>>
>> Fixes: 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code")
>> Cc: stable@ger.kernel.org

Ah, so you did something wrong after all :-p. The email address should
be 'stable@vger.kernel.org'.

>> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
>> ---
>>
>> scripts/checkpatch.pl reports a warning: "Prefer ether_addr_equal() or
>> ether_addr_equal_unaligned() over memcmp()".  Because some files in
>> drivers/net/wireless/broadcom/brcm80211/brcmfmac/ still use memcmp()
>> to compare addresses and because I do not know whether pmksa->bssid is
>> always aligned, I did not follow this warning.

As most of this is done in slow path, I prefer memcmp() as I do not want
to check alignment for minimal performance gain.

>>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> index 2628d5e12c64..aceab77cd95a 100644
>> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> @@ -3884,11 +3884,11 @@ brcmf_cfg80211_del_pmksa(struct wiphy *wiphy, struct net_device *ndev,
>>  	if (!check_vif_up(ifp->vif))
>>  		return -EIO;
>>  
>> -	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", &pmksa->bssid);
>> +	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", pmksa->bssid);
>>  
>>  	npmk = le32_to_cpu(cfg->pmk_list.npmk);
>>  	for (i = 0; i < npmk; i++)
>> -		if (!memcmp(&pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
>> +		if (!memcmp(pmksa->bssid, &pmk[i].bssid, ETH_ALEN))

I find '&pmk[i].bssid' confusing so maybe you could change it to
'&pmk[i].bssid[0]' or 'pmk[i].bssid' as I think these two are
essentially the same.

Regards,
Arend

>>  			break;
>>  
>>  	if ((npmk > 0) && (i < npmk)) {
>>
> 

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#1468441

On 22/08/16 21:38, Arend Van Spriel wrote:
> On 22-8-2016 15:03, Nicolas Iooss wrote:
>> On 05/08/16 22:34, Nicolas Iooss wrote:
[...]
>>> Fixes: 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code")
>>> Cc: stable@ger.kernel.org
> 
> Ah, so you did something wrong after all :-p. The email address should
> be 'stable@vger.kernel.org'.

Thanks for spotting this! I'll fix this address.

>>> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
>>> ---
>>>
>>> scripts/checkpatch.pl reports a warning: "Prefer ether_addr_equal() or
>>> ether_addr_equal_unaligned() over memcmp()".  Because some files in
>>> drivers/net/wireless/broadcom/brcm80211/brcmfmac/ still use memcmp()
>>> to compare addresses and because I do not know whether pmksa->bssid is
>>> always aligned, I did not follow this warning.
> 
> As most of this is done in slow path, I prefer memcmp() as I do not want
> to check alignment for minimal performance gain.

OK.

>>>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>>> index 2628d5e12c64..aceab77cd95a 100644
>>> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>>> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>>> @@ -3884,11 +3884,11 @@ brcmf_cfg80211_del_pmksa(struct wiphy *wiphy, struct net_device *ndev,
>>>  	if (!check_vif_up(ifp->vif))
>>>  		return -EIO;
>>>  
>>> -	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", &pmksa->bssid);
>>> +	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", pmksa->bssid);
>>>  
>>>  	npmk = le32_to_cpu(cfg->pmk_list.npmk);
>>>  	for (i = 0; i < npmk; i++)
>>> -		if (!memcmp(&pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
>>> +		if (!memcmp(pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
> 
> I find '&pmk[i].bssid' confusing so maybe you could change it to
> '&pmk[i].bssid[0]' or 'pmk[i].bssid' as I think these two are
> essentially the same.

I agree the three ways of writing this share the same meaning. I'll send
a v2 with 'pmk[i].bssid'.
> 
> Regards,
> Arend

Thanks for your review!
Nicolas

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#1468445 — [PATCH v2 1/1] brcmfmac: fix pmksa->bssid usage

The struct cfg80211_pmksa defines its bssid field as:

    const u8 *bssid;

contrary to struct brcmf_pmksa, which uses:

    u8 bssid[ETH_ALEN];

Therefore in brcmf_cfg80211_del_pmksa(), &pmksa->bssid takes the address
of this field (of type u8**), not the one of its content (which would be
u8*).  Remove the & operator to make brcmf_dbg("%pM") and memcmp()
behave as expected.

This bug have been found using a custom static checker (which checks the
usage of %p... attributes at build time).  It has been introduced in
commit 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code"),
which replaced pmksa->bssid by &pmksa->bssid while refactoring the code,
without modifying struct cfg80211_pmksa definition.

Replace &pmk[i].bssid with pmk[i].bssid too to make the code clearer,
this change does not affect the semantic.

Fixes: 6c404f34f2bd ("brcmfmac: Cleanup pmksa cache handling code")
Cc: stable@vger.kernel.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index 2628d5e12c64..201a98016142 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -3884,11 +3884,11 @@ brcmf_cfg80211_del_pmksa(struct wiphy *wiphy, struct net_device *ndev,
 	if (!check_vif_up(ifp->vif))
 		return -EIO;
 
-	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", &pmksa->bssid);
+	brcmf_dbg(CONN, "del_pmksa - PMK bssid = %pM\n", pmksa->bssid);
 
 	npmk = le32_to_cpu(cfg->pmk_list.npmk);
 	for (i = 0; i < npmk; i++)
-		if (!memcmp(&pmksa->bssid, &pmk[i].bssid, ETH_ALEN))
+		if (!memcmp(pmksa->bssid, pmk[i].bssid, ETH_ALEN))
 			break;
 
 	if ((npmk > 0) && (i < npmk)) {
-- 
2.9.3

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