FAILED: Patch "HID: magicmouse: Do not crash on missing msc->input" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 17abd396548035fbd6179ee1a431bd75d49676a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCnther=20Noack?= <gnoack@google.com>
Date: Fri, 9 Jan 2026 11:57:14 +0100
Subject: [PATCH] HID: magicmouse: Do not crash on missing msc->input
MIME-Version: 1.0
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Fake USB devices can send their own report descriptors for which the
input_mapping() hook does not get called.  In this case, msc->input stays NULL,
leading to a crash at a later time.

Detect this condition in the input_configured() hook and reject the device.

This is not supposed to happen with actual magic mouse devices, but can be
provoked by imposing as a magic mouse USB device.

Cc: stable@vger.kernel.org
Signed-off-by: Günther Noack <gnoack@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
---
 drivers/hid/hid-magicmouse.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index 7d4a25c6de0eb..91f621ceb924b 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -725,6 +725,11 @@ static int magicmouse_input_configured(struct hid_device *hdev,
 	struct magicmouse_sc *msc = hid_get_drvdata(hdev);
 	int ret;
 
+	if (!msc->input) {
+		hid_err(hdev, "magicmouse setup input failed (no input)");
+		return -EINVAL;
+	}
+
 	ret = magicmouse_setup_input(msc->input, hdev);
 	if (ret) {
 		hid_err(hdev, "magicmouse setup input failed (%d)\n", ret);
-- 
2.51.0