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authorEliad Peller <eliad@wizery.com>2013-12-05 18:30:17 +0200
committerJohannes Berg <johannes.berg@intel.com>2013-12-05 19:06:47 +0100
commit4a58e7c38443154fce1b47910e1a9184f65c5d72 (patch)
tree312b02efaf0de0522cca0eebfac2b5b861430d68 /net/wireless
parenta2b70e833e189a4aefb2d3b668e3d7046dcc45c2 (diff)
downloadop-kernel-dev-4a58e7c38443154fce1b47910e1a9184f65c5d72.zip
op-kernel-dev-4a58e7c38443154fce1b47910e1a9184f65c5d72.tar.gz
cfg80211: don't "leak" uncompleted scans
___cfg80211_scan_done() can be called in some cases (e.g. on NETDEV_DOWN) before the low level driver notified scan completion (which is indicated by passing leak=true). Clearing rdev->scan_req in this case is buggy, as scan_done_wk might have already being queued/running (and can't be flushed as it takes rtnl()). If a new scan will be requested at this stage, the scan_done_wk will try freeing it (instead of the previous scan), and this will later result in a use after free. Simply remove the "leak" option, and replace it with a standard WARN_ON. An example backtrace after such crash: Unable to handle kernel paging request at virtual address fffffee5 pgd = c0004000 [fffffee5] *pgd=9fdf6821, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] SMP ARM PC is at cfg80211_scan_done+0x28/0xc4 [cfg80211] LR is at __ieee80211_scan_completed+0xe4/0x2dc [mac80211] [<bf0077b0>] (cfg80211_scan_done+0x28/0xc4 [cfg80211]) [<bf0973d4>] (__ieee80211_scan_completed+0xe4/0x2dc [mac80211]) [<bf0982cc>] (ieee80211_scan_work+0x94/0x4f0 [mac80211]) [<c005fd10>] (process_one_work+0x1b0/0x4a8) [<c0060404>] (worker_thread+0x138/0x37c) [<c0066d70>] (kthread+0xa4/0xb0) Signed-off-by: Eliad Peller <eliad@wizery.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/wireless')
-rw-r--r--net/wireless/core.c20
-rw-r--r--net/wireless/core.h2
-rw-r--r--net/wireless/scan.c16
3 files changed, 8 insertions, 30 deletions
diff --git a/net/wireless/core.c b/net/wireless/core.c
index c044355..1a92c6a 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -203,17 +203,8 @@ void cfg80211_stop_p2p_device(struct cfg80211_registered_device *rdev,
rdev->opencount--;
- if (rdev->scan_req && rdev->scan_req->wdev == wdev) {
- /*
- * If the scan request wasn't notified as done, set it
- * to aborted and leak it after a warning. The driver
- * should have notified us that it ended at the latest
- * during rdev_stop_p2p_device().
- */
- if (WARN_ON(!rdev->scan_req->notified))
- rdev->scan_req->aborted = true;
- ___cfg80211_scan_done(rdev, !rdev->scan_req->notified);
- }
+ WARN_ON(rdev->scan_req && rdev->scan_req->wdev == wdev &&
+ !rdev->scan_req->notified);
}
static int cfg80211_rfkill_set_block(void *data, bool blocked)
@@ -859,11 +850,8 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
break;
case NETDEV_DOWN:
cfg80211_update_iface_num(rdev, wdev->iftype, -1);
- if (rdev->scan_req && rdev->scan_req->wdev == wdev) {
- if (WARN_ON(!rdev->scan_req->notified))
- rdev->scan_req->aborted = true;
- ___cfg80211_scan_done(rdev, true);
- }
+ WARN_ON(rdev->scan_req && rdev->scan_req->wdev == wdev &&
+ !rdev->scan_req->notified);
if (WARN_ON(rdev->sched_scan_req &&
rdev->sched_scan_req->dev == wdev->netdev)) {
diff --git a/net/wireless/core.h b/net/wireless/core.h
index ac77644..453c6ed 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -361,7 +361,7 @@ int cfg80211_validate_key_settings(struct cfg80211_registered_device *rdev,
struct key_params *params, int key_idx,
bool pairwise, const u8 *mac_addr);
void __cfg80211_scan_done(struct work_struct *wk);
-void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak);
+void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev);
void __cfg80211_sched_scan_results(struct work_struct *wk);
int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
bool driver_initiated);
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index d4397eb..a32d52a 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -161,7 +161,7 @@ static void __cfg80211_bss_expire(struct cfg80211_registered_device *dev,
dev->bss_generation++;
}
-void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
+void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev)
{
struct cfg80211_scan_request *request;
struct wireless_dev *wdev;
@@ -210,17 +210,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
dev_put(wdev->netdev);
rdev->scan_req = NULL;
-
- /*
- * OK. If this is invoked with "leak" then we can't
- * free this ... but we've cleaned it up anyway. The
- * driver failed to call the scan_done callback, so
- * all bets are off, it might still be trying to use
- * the scan request or not ... if it accesses the dev
- * in there (it shouldn't anyway) then it may crash.
- */
- if (!leak)
- kfree(request);
+ kfree(request);
}
void __cfg80211_scan_done(struct work_struct *wk)
@@ -231,7 +221,7 @@ void __cfg80211_scan_done(struct work_struct *wk)
scan_done_wk);
rtnl_lock();
- ___cfg80211_scan_done(rdev, false);
+ ___cfg80211_scan_done(rdev);
rtnl_unlock();
}
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