From: Ivan Kuten <ivan.kuten@promwad.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: John Linville <linville@tuxdriver.com>,
Yauhen Kharuzhy <yauhen.kharuzhy@promwad.com>,
linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH] cfg80211: fix alignment problem in scan request
Date: Mon, 10 Aug 2009 15:09:59 +0300 [thread overview]
Message-ID: <4A800E17.3000002@promwad.com> (raw)
In-Reply-To: <1249660447.7194.9.camel@johannes.local>
Johannes,
I can test only on compat-wireless.
> The memory layout for scan requests was rather wrong,
> we put the scan SSIDs before the channels which could
> lead to the channel pointers being unaligned in memory.
> It turns out that using a pointer to the channel array
> isn't necessary anyway since we can embed a zero-length
> array into the struct.
>
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> ---
> include/net/cfg80211.h | 4 +++-
> net/mac80211/ieee80211_i.h | 2 +-
> net/mac80211/main.c | 16 ++++++++--------
> net/mac80211/scan.c | 10 +++++-----
> net/wireless/nl80211.c | 3 +--
> net/wireless/scan.c | 4 ++--
> net/wireless/sme.c | 3 +--
> 7 files changed, 21 insertions(+), 21 deletions(-)
>
> --- wireless-testing.orig/include/net/cfg80211.h 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/include/net/cfg80211.h 2009-08-07 17:49:06.000000000 +0200
> @@ -559,7 +559,6 @@ struct cfg80211_ssid {
> struct cfg80211_scan_request {
> struct cfg80211_ssid *ssids;
> int n_ssids;
> - struct ieee80211_channel **channels;
> u32 n_channels;
> const u8 *ie;
> size_t ie_len;
> @@ -568,6 +567,9 @@ struct cfg80211_scan_request {
> struct wiphy *wiphy;
> struct net_device *dev;
> bool aborted;
> +
> + /* keep last */
> + struct ieee80211_channel *channels[0];
> };
>
> /**
> --- wireless-testing.orig/net/wireless/nl80211.c 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/wireless/nl80211.c 2009-08-07 17:49:06.000000000 +0200
> @@ -3002,10 +3002,9 @@ static int nl80211_trigger_scan(struct s
> goto out;
> }
>
> - request->channels = (void *)((char *)request + sizeof(*request));
> request->n_channels = n_channels;
> if (n_ssids)
> - request->ssids = (void *)(request->channels + n_channels);
> + request->ssids = (void *)&request->channels[n_channels];
> request->n_ssids = n_ssids;
> if (ie_len) {
> if (request->ssids)
> --- wireless-testing.orig/net/wireless/scan.c 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/wireless/scan.c 2009-08-07 17:49:06.000000000 +0200
> @@ -612,8 +612,8 @@ int cfg80211_wext_siwscan(struct net_dev
>
> creq->wiphy = wiphy;
> creq->dev = dev;
> - creq->ssids = (void *)(creq + 1);
> - creq->channels = (void *)(creq->ssids + 1);
> + /* SSIDs come after channels */
> + creq->ssids = (void *)&creq->channels[n_channels];
> creq->n_channels = n_channels;
> creq->n_ssids = 1;
>
> --- wireless-testing.orig/net/wireless/sme.c 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/wireless/sme.c 2009-08-07 17:49:06.000000000 +0200
> @@ -65,7 +65,6 @@ static int cfg80211_conn_scan(struct wir
> if (!request)
> return -ENOMEM;
>
> - request->channels = (void *)((char *)request + sizeof(*request));
> if (wdev->conn->params.channel)
> request->channels[0] = wdev->conn->params.channel;
> else {
> @@ -82,7 +81,7 @@ static int cfg80211_conn_scan(struct wir
> }
> }
> request->n_channels = n_channels;
> - request->ssids = (void *)(request->channels + n_channels);
> + request->ssids = (void *)&request->channels[n_channels];
> request->n_ssids = 1;
>
> memcpy(request->ssids[0].ssid, wdev->conn->params.ssid,
> --- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/mac80211/ieee80211_i.h 2009-08-07 17:49:06.000000000 +0200
> @@ -715,7 +715,7 @@ struct ieee80211_local {
> struct mutex scan_mtx;
> unsigned long scanning;
> struct cfg80211_ssid scan_ssid;
> - struct cfg80211_scan_request int_scan_req;
> + struct cfg80211_scan_request *int_scan_req;
> struct cfg80211_scan_request *scan_req;
> struct ieee80211_channel *scan_channel;
> const u8 *orig_ies;
> --- wireless-testing.orig/net/mac80211/main.c 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/mac80211/main.c 2009-08-07 17:49:06.000000000 +0200
> @@ -765,9 +765,9 @@ int ieee80211_register_hw(struct ieee802
> supp_ht = supp_ht || sband->ht_cap.ht_supported;
> }
>
> - local->int_scan_req.n_channels = channels;
> - local->int_scan_req.channels = kzalloc(sizeof(void *) * channels, GFP_KERNEL);
> - if (!local->int_scan_req.channels)
> + local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) +
> + sizeof(void *) * channels, GFP_KERNEL);
> + if (!local->int_scan_req)
> return -ENOMEM;
>
> /* if low-level driver supports AP, we also support VLAN */
> @@ -882,13 +882,13 @@ int ieee80211_register_hw(struct ieee802
>
> /* alloc internal scan request */
> i = 0;
> - local->int_scan_req.ssids = &local->scan_ssid;
> - local->int_scan_req.n_ssids = 1;
> + local->int_scan_req->ssids = &local->scan_ssid;
> + local->int_scan_req->n_ssids = 1;
> for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
> if (!hw->wiphy->bands[band])
> continue;
> for (j = 0; j < hw->wiphy->bands[band]->n_channels; j++) {
> - local->int_scan_req.channels[i] =
> + local->int_scan_req->channels[i] =
> &hw->wiphy->bands[band]->channels[j];
> i++;
> }
> @@ -920,7 +920,7 @@ int ieee80211_register_hw(struct ieee802
> fail_workqueue:
> wiphy_unregister(local->hw.wiphy);
> fail_wiphy_register:
> - kfree(local->int_scan_req.channels);
> + kfree(local->int_scan_req->channels);
> return result;
> }
> EXPORT_SYMBOL(ieee80211_register_hw);
> @@ -962,7 +962,7 @@ void ieee80211_unregister_hw(struct ieee
> wiphy_unregister(local->hw.wiphy);
> ieee80211_wep_free(local);
> ieee80211_led_exit(local);
> - kfree(local->int_scan_req.channels);
> + kfree(local->int_scan_req);
> }
> EXPORT_SYMBOL(ieee80211_unregister_hw);
>
> --- wireless-testing.orig/net/mac80211/scan.c 2009-08-07 17:49:05.000000000 +0200
> +++ wireless-testing/net/mac80211/scan.c 2009-08-07 17:49:06.000000000 +0200
> @@ -277,7 +277,7 @@ void ieee80211_scan_completed(struct iee
> if (test_bit(SCAN_HW_SCANNING, &local->scanning))
> ieee80211_restore_scan_ies(local);
>
> - if (local->scan_req != &local->int_scan_req)
> + if (local->scan_req != local->int_scan_req)
> cfg80211_scan_done(local->scan_req, aborted);
> local->scan_req = NULL;
>
> @@ -423,7 +423,7 @@ static int __ieee80211_start_scan(struct
> local->scan_req = req;
> local->scan_sdata = sdata;
>
> - if (req != &local->int_scan_req &&
> + if (req != local->int_scan_req &&
> sdata->vif.type == NL80211_IFTYPE_STATION &&
> !list_empty(&ifmgd->work_list)) {
> /* actually wait for the work it's doing to finish/time out */
> @@ -743,10 +743,10 @@ int ieee80211_request_internal_scan(stru
> if (local->scan_req)
> goto unlock;
>
> - memcpy(local->int_scan_req.ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
> - local->int_scan_req.ssids[0].ssid_len = ssid_len;
> + memcpy(local->int_scan_req->ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN);
> + local->int_scan_req->ssids[0].ssid_len = ssid_len;
>
> - ret = __ieee80211_start_scan(sdata, &sdata->local->int_scan_req);
> + ret = __ieee80211_start_scan(sdata, sdata->local->int_scan_req);
> unlock:
> mutex_unlock(&local->scan_mtx);
> return ret;
>
>
>
>
>
next prev parent reply other threads:[~2009-08-10 12:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-07 15:54 [PATCH] cfg80211: fix alignment problem in scan request Johannes Berg
2009-08-10 12:09 ` Ivan Kuten [this message]
2009-08-10 15:11 ` John W. Linville
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