From: Ivan Kuten <ivan.kuten@promwad.com>
To: linux-wireless@vger.kernel.org
Cc: Johannes Berg <johannes@sipsolutions.net>,
Yauhen Kharuzhy <yauhen.kharuzhy@promwad.com>
Subject: Re: [PATCH] wireless: Compare ethernet addresses by unaligned safe way
Date: Sun, 28 Jun 2009 15:18:10 +0300 [thread overview]
Message-ID: <4A475F82.9040007@promwad.com> (raw)
In-Reply-To: <1245150895.8623.3.camel@johannes.local>
Hello,
In net/wireless/scan.c : cfg80211_wext_siwscan there seems also unaligned allocations
for creq->ssids and creq->channels. Should it be something like that?
Modified: trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c
==============================================================================
--- trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c (original)
+++ trunk/uClinux-dist-2008R1-RC8/compat-wireless-2009-06-11/net/wireless/scan.c Fri Jun 26 14:00:52 2009
@@ -619,7 +619,7 @@
if (wiphy->bands[band])
n_channels += wiphy->bands[band]->n_channels;
- creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
+ creq = kzalloc(roundup(sizeof(*creq), 4) + roundup(sizeof(struct cfg80211_ssid), 4) +
n_channels * sizeof(void *),
GFP_ATOMIC);
if (!creq) {
@@ -629,8 +629,8 @@
creq->wiphy = wiphy;
creq->ifidx = dev->ifindex;
- creq->ssids = (void *)(creq + 1);
- creq->channels = (void *)(creq->ssids + 1);
+ creq->ssids = (void *)creq + roundup(sizeof(*creq), 4);
+ creq->channels = (void *)creq->ssids + roundup(sizeof(*creq->ssids), 4);
creq->n_channels = n_channels;
creq->n_ssids = 1;
Regards,
Ivan
> On Tue, 2009-06-16 at 13:54 +0300, Yauhen Kharuzhy wrote:
>> When we try to run RTL8187 driver on AD BlackFin platform, we got
>> messages from kernel about unaligned memory access at
>> compare_ether_addr() calls.
>>
>> Replacing of compare_ether_addr() by memcmp() fixes this problem.
>
> This shouldn't be necessary. Which operand is unaligned?
>
>> --- a/net/mac80211/ibss.c
>> +++ b/net/mac80211/ibss.c
>> @@ -395,7 +395,7 @@ struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
>> return NULL;
>> }
>>
>> - if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
>> + if (memcmp(bssid, sdata->u.ibss.bssid, ETH_ALEN))
>> return NULL;
>
> So in this case it seems that it is possible that u.ibss.bssid is not
> aligned, consider fixing by doing
>
> --- ieee80211_i.h
> +++ ieee80211_i.h
> - u8 bssid[ETH_ALEN];
> + u8 bssid[ETH_ALEN] __align(2);
>
> or so instead.
>
>> --- a/net/wireless/scan.c
>> +++ b/net/wireless/scan.c
>> @@ -134,7 +134,7 @@ static bool is_bss(struct cfg80211_bss *a,
>> {
>> const u8 *ssidie;
>>
>> - if (bssid && compare_ether_addr(a->bssid, bssid))
>> + if (bssid && memcmp(a->bssid, bssid, ETH_ALEN))
>
> Since a->bssid is after a pointer I can't see how it would be unaligned,
> and bssid should be unaligned only if the call trace shows it's coming
> from the above u.ibss.bssid.
>
> johannes
next prev parent reply other threads:[~2009-06-28 12:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 10:54 [PATCH] wireless: Compare ethernet addresses by unaligned safe way Yauhen Kharuzhy
2009-06-16 11:14 ` Johannes Berg
2009-06-28 12:18 ` Ivan Kuten [this message]
2009-06-29 7:58 ` Johannes Berg
2009-07-23 17:56 ` Ivan Kuten
2009-07-23 17:59 ` Johannes Berg
2009-08-07 15:34 ` John W. Linville
2009-06-29 8:23 ` Johannes Berg
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