Hello Jiawei,
On 9/19/24 14:26, Jiawei Ye wrote:
On 9/19/24 17:01, Przemek Kitszel wrote:
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: e2c3e6f53a7a ("mac802154: Handle active scanning")
Signed-off-by: Jiawei Ye <jiawei.ye@xxxxxxxxxxx>
---
net/mac802154/scan.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/mac802154/scan.c b/net/mac802154/scan.c
index 1c0eeaa76560..29cd84c9f69c 100644
--- a/net/mac802154/scan.c
+++ b/net/mac802154/scan.c
@@ -180,6 +180,7 @@ void mac802154_scan_worker(struct work_struct *work)
unsigned int scan_duration = 0;
struct wpan_phy *wpan_phy;
u8 scan_req_duration;
+ enum nl802154_scan_types scan_req_type;
this line violates the reverse X-mass tree rule of code formatting
Thank you for pointing out the concern regarding the violation of the
reverse Christmas tree rule. I will adjust the placement of
`enum nl802154_scan_types scan_req_type` to be between
`struct cfg802154_scan_request *scan_req` and
`struct ieee802154_sub_if_data *sdata`. If this change is suitable,
should I resend the patch as a v2 patch?
Yes, please always increase the version whenever you change something
and re-send. Also a ChangeLog of the changes makes it a lot easier for
the reviewer.
regards
Stefan Schmidt
