If the device is plugged/unplugged without giving time for mcp_init_work()
to complete, we might kick in the devm free code path and thus have
unavailable struct mcp_2221 while in delayed work.
Canceling the delayed_work item is enough to solve the issue, because
cancel_delayed_work_sync will prevent the work item to requeue itself.
Signed-off-by: Benjamin Tissoires <[email protected]>
---
Similar to Pietro's series, we can see the pattern in hid-mcp2221,
except that this time the ledclass is not involved.
Link: https://lore.kernel.org/linux-input/[email protected]/
---
Changes in v2:
- drop the spinlock/boolean
- Link to v1: https://lore.kernel.org/r/[email protected]
---
drivers/hid/hid-mcp2221.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
index e61dd039354b..f74a977cf8f8 100644
--- a/drivers/hid/hid-mcp2221.c
+++ b/drivers/hid/hid-mcp2221.c
@@ -922,6 +922,9 @@ static void mcp2221_hid_unregister(void *ptr)
/* This is needed to be sure hid_hw_stop() isn't called twice by the subsystem */
static void mcp2221_remove(struct hid_device *hdev)
{
+ struct mcp2221 *mcp = hid_get_drvdata(hdev);
+
+ cancel_delayed_work_sync(&mcp->init_work);
}
#if IS_REACHABLE(CONFIG_IIO)
---
base-commit: d883fd110dc17308a1506c5bf17e00ce9fe7b2a2
change-id: 20230215-wip-mcp2221-979d4115efb5
Best regards,
--
Benjamin Tissoires <[email protected]>
On Thu, 16 Feb 2023, Benjamin Tissoires wrote:
> If the device is plugged/unplugged without giving time for mcp_init_work()
> to complete, we might kick in the devm free code path and thus have
> unavailable struct mcp_2221 while in delayed work.
>
> Canceling the delayed_work item is enough to solve the issue, because
> cancel_delayed_work_sync will prevent the work item to requeue itself.
>
> Signed-off-by: Benjamin Tissoires <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Thanks Benjamin.
--
Jiri Kosina
SUSE Labs
On Mon, Feb 20, 2023 at 10:10 AM Jiri Kosina <[email protected]> wrote:
>
> On Thu, 16 Feb 2023, Benjamin Tissoires wrote:
>
> > If the device is plugged/unplugged without giving time for mcp_init_work()
> > to complete, we might kick in the devm free code path and thus have
> > unavailable struct mcp_2221 while in delayed work.
> >
> > Canceling the delayed_work item is enough to solve the issue, because
> > cancel_delayed_work_sync will prevent the work item to requeue itself.
> >
> > Signed-off-by: Benjamin Tissoires <[email protected]>
>
> Acked-by: Jiri Kosina <[email protected]>
Thanks a lot.
I realized I was missing the Fixes 960f9df7c620 and Cc: stable tags.
I am adding those right now and will push it as soon as the minimum CI
reports back that it's OK.
Cheers,
Benjamin
>
> Thanks Benjamin.
>
> --
> Jiri Kosina
> SUSE Labs
>
On Thu, 16 Feb 2023 11:22:58 +0100, Benjamin Tissoires wrote:
> If the device is plugged/unplugged without giving time for mcp_init_work()
> to complete, we might kick in the devm free code path and thus have
> unavailable struct mcp_2221 while in delayed work.
>
> Canceling the delayed_work item is enough to solve the issue, because
> cancel_delayed_work_sync will prevent the work item to requeue itself.
>
> [...]
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git (for-6.3/mcp2221), thanks!
[1/1] HID: mcp-2221: prevent UAF in delayed work
https://git.kernel.org/hid/hid/c/47e91fdfa511
Cheers,
--
Benjamin Tissoires <[email protected]>