qcom_glink_rpdev_release() sets channel->rpdev to NULL. However, with
debug enabled kernel, qcom_glink_rpdev_release() gets delayed due to
delayed kobject release and channel gets released by that time and
triggers below kernel warning. To avoid this use-after-free, clear ept
pointers during ept destroy and channel release and add a new condition
in qcom_glink_rpdev_release() to access channel
| BUG: KASAN: use-after-free in qcom_glink_rpdev_release+0x54/0x70
| Write of size 8 at addr ffffffaba438e8d0 by task kworker/6:1/54
|
| CPU: 6 PID: 54 Comm: kworker/6:1 Not tainted 5.4.109-lockdep #16
| Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
| Workqueue: events kobject_delayed_cleanup
| Call trace:
| dump_backtrace+0x0/0x284
| show_stack+0x20/0x2c
| dump_stack+0xd4/0x170
| print_address_description+0x3c/0x4a8
| __kasan_report+0x144/0x168
| kasan_report+0x10/0x18
| __asan_report_store8_noabort+0x1c/0x24
| qcom_glink_rpdev_release+0x54/0x70
| device_release+0x68/0x14c
| kobject_delayed_cleanup+0x158/0x2cc
| process_one_work+0x7cc/0x10a4
| worker_thread+0x80c/0xcec
| kthread+0x2a8/0x314
| ret_from_fork+0x10/0x18
Signed-off-by: Sujit Kautkar <sujitka@xxxxxxxxxxxx>
---
Changes in v3:
- Clear ept pointers and add extra conditions
Changes in v2:
- Fix typo in commit message
drivers/rpmsg/qcom_glink_native.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index e1444fefdd1c0..0c64a6f7a4f09 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -269,6 +269,9 @@ static void qcom_glink_channel_release(struct kref *ref)
idr_destroy(&channel->riids);
spin_unlock_irqrestore(&channel->intent_lock, flags);
+ if (channel->rpdev)
+ channel->rpdev->ept = NULL;
+
kfree(channel->name);
kfree(channel);
}
@@ -1214,6 +1217,8 @@ static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
channel->ept.cb = NULL;
spin_unlock_irqrestore(&channel->recv_lock, flags);
+ channel->rpdev->ept = NULL;
+
/* Decouple the potential rpdev from the channel */
channel->rpdev = NULL;
@@ -1371,9 +1376,12 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
static void qcom_glink_rpdev_release(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
- struct glink_channel *channel = to_glink_channel(rpdev->ept);
+ struct glink_channel *channel = NULL;
- channel->rpdev = NULL;
+ if (rpdev->ept) {
+ channel = to_glink_channel(rpdev->ept);
+ channel->rpdev = NULL;
+ }
kfree(rpdev);
}
--
2.31.0
