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| author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2018-12-14 11:55:21 +0800 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2018-12-20 08:49:37 +0200 |
| commit | 4f68ef64cd7feb1220232bd8f501d8aad340a099 (patch) | |
| tree | b6d9ee5f7b9342b98e37c18967613e9ff638a861 /drivers/net/wireless/st | |
| parent | 861cb5eb467f5e38dce1aabe4e8db379255bd89b (diff) | |
| download | linux-4f68ef64cd7feb1220232bd8f501d8aad340a099.tar.bz2 | |
cw1200: Fix concurrency use-after-free bugs in cw1200_hw_scan()
The function cw1200_bss_info_changed() and cw1200_hw_scan() can be
concurrently executed.
The two functions both access a possible shared variable "frame.skb".
This shared variable is freed by dev_kfree_skb() in cw1200_upload_beacon(),
which is called by cw1200_bss_info_changed(). The free operation is
protected by a mutex lock "priv->conf_mutex" in cw1200_bss_info_changed().
In cw1200_hw_scan(), this shared variable is accessed without the
protection of the mutex lock "priv->conf_mutex".
Thus, concurrency use-after-free bugs may occur.
To fix these bugs, the original calls to mutex_lock(&priv->conf_mutex) and
mutex_unlock(&priv->conf_mutex) are moved to the places, which can
protect the accesses to the shared variable.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Diffstat (limited to 'drivers/net/wireless/st')
| -rw-r--r-- | drivers/net/wireless/st/cw1200/scan.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/net/wireless/st/cw1200/scan.c b/drivers/net/wireless/st/cw1200/scan.c index 67213f11acbd..0a9eac93dd01 100644 --- a/drivers/net/wireless/st/cw1200/scan.c +++ b/drivers/net/wireless/st/cw1200/scan.c @@ -78,6 +78,10 @@ int cw1200_hw_scan(struct ieee80211_hw *hw, if (req->n_ssids > WSM_SCAN_MAX_NUM_OF_SSIDS) return -EINVAL; + /* will be unlocked in cw1200_scan_work() */ + down(&priv->scan.lock); + mutex_lock(&priv->conf_mutex); + frame.skb = ieee80211_probereq_get(hw, priv->vif->addr, NULL, 0, req->ie_len); if (!frame.skb) @@ -86,19 +90,15 @@ int cw1200_hw_scan(struct ieee80211_hw *hw, if (req->ie_len) skb_put_data(frame.skb, req->ie, req->ie_len); - /* will be unlocked in cw1200_scan_work() */ - down(&priv->scan.lock); - mutex_lock(&priv->conf_mutex); - ret = wsm_set_template_frame(priv, &frame); if (!ret) { /* Host want to be the probe responder. */ ret = wsm_set_probe_responder(priv, true); } if (ret) { + dev_kfree_skb(frame.skb); mutex_unlock(&priv->conf_mutex); up(&priv->scan.lock); - dev_kfree_skb(frame.skb); return ret; } @@ -120,10 +120,9 @@ int cw1200_hw_scan(struct ieee80211_hw *hw, ++priv->scan.n_ssids; } - mutex_unlock(&priv->conf_mutex); - if (frame.skb) dev_kfree_skb(frame.skb); + mutex_unlock(&priv->conf_mutex); queue_work(priv->workqueue, &priv->scan.work); return 0; } |