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mac802154: Fix potential RCU dereference issue in mac802154_scan_worker

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In the `mac802154_scan_worker` function, the `scan_req->type` field was
accessed after the RCU read-side critical section was unlocked. According
to RCU usage rules, this is illegal and can lead to unpredictable
behavior, such as accessing memory that has been updated or causing
use-after-free issues.

This possible bug was identified using a static analysis tool developed
by myself, specifically designed to detect RCU-related issues.

To address this, the `scan_req->type` value is now stored in a local
variable `scan_req_type` while still within the RCU read-side critical
section. The `scan_req_type` is then used after the RCU lock is released,
ensuring that the type value is safely accessed without violating RCU
rules.

Fixes: e2c3e6f53a ("mac802154: Handle active scanning")
Cc: stable@vger.kernel.org
Signed-off-by: Jiawei Ye <jiawei.ye@foxmail.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/tencent_3B2F4F2B4DA30FAE2F51A9634A16B3AD4908@qq.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
This commit is contained in:
Jiawei Ye 2024-09-24 06:58:05 +00:00 committed by Stefan Schmidt
parent addf89774e
commit bff1709b39
1 changed files with 3 additions and 1 deletions
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4
net/mac802154/scan.c
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@ -176,6 +176,7 @@ void mac802154_scan_worker(struct work_struct *work)
struct ieee802154_local *local = struct ieee802154_local *local =
container_of(work, struct ieee802154_local, scan_work.work); container_of(work, struct ieee802154_local, scan_work.work);
struct cfg802154_scan_request *scan_req; struct cfg802154_scan_request *scan_req;
enum nl802154_scan_types scan_req_type;
struct ieee802154_sub_if_data *sdata; struct ieee802154_sub_if_data *sdata;
unsigned int scan_duration = 0; unsigned int scan_duration = 0;
struct wpan_phy *wpan_phy; struct wpan_phy *wpan_phy;
@ -209,6 +210,7 @@ void mac802154_scan_worker(struct work_struct *work)
} }
wpan_phy = scan_req->wpan_phy; wpan_phy = scan_req->wpan_phy;
scan_req_type = scan_req->type;
scan_req_duration = scan_req->duration; scan_req_duration = scan_req->duration;
/* Look for the next valid chan */ /* Look for the next valid chan */
@ -246,7 +248,7 @@ void mac802154_scan_worker(struct work_struct *work)
goto end_scan; goto end_scan;
} }
if (scan_req->type == NL802154_SCAN_ACTIVE) { if (scan_req_type == NL802154_SCAN_ACTIVE) {
ret = mac802154_transmit_beacon_req(local, sdata); ret = mac802154_transmit_beacon_req(local, sdata);
if (ret) if (ret)
dev_err(&sdata->dev->dev, dev_err(&sdata->dev->dev,