[PATCH 5.15 188/206] HID: uclogic: Correct devm device reference for hidinput input_dev name

Greg Kroah-Hartman
2026-02-04T15:01:59Z

From: Rahul Rameshbabu <sergeantsagara@protonmail.com>

[ Upstream commit dd613a4e45f8d35f49a63a2064e5308fa5619e29 ]

Reference the HID device rather than the input device for the devm
allocation of the input_dev name. Referencing the input_dev would lead to a
use-after-free when the input_dev was unregistered and subsequently fires a
uevent that depends on the name. At the point of firing the uevent, the
name would be freed by devres management.

Use devm_kasprintf to simplify the logic for allocating memory and
formatting the input_dev name string.

Reported-by: syzbot+3a0ebe8a52b89c63739d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-input/ZOZIZCND+L0P1wJc@penguin/T/
Reported-by: Maxime Ripard <mripard@kernel.org>
Closes: https://lore.kernel.org/linux-input/ZOZIZCND+L0P1wJc@penguin/T/#m443f3dce92520f74b6cf6ffa8653f9c92643d4ae
Fixes: cce2dbdf258e ("HID: uclogic: name the input nodes based on their tool")
Suggested-by: Maxime Ripard <mripard@kernel.org>
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rahul Rameshbabu <sergeantsagara@protonmail.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20230824061308.222021-2-sergeantsagara@protonmail.com
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
[ Adjust context ]
Signed-off-by: Wenshan Lan <jetlan9@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/hid-uclogic-core.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)

--- a/drivers/hid/hid-uclogic-core.c
+++ b/drivers/hid/hid-uclogic-core.c
@@ -104,10 +104,8 @@ static int uclogic_input_configured(stru
{
struct uclogic_drvdata *drvdata = hid_get_drvdata(hdev);
struct uclogic_params *params = &drvdata->params;
- char *name;
const char *suffix = NULL;
struct hid_field *field;
- size_t len;

/* no report associated (HID_QUIRK_MULTI_INPUT not set) */
if (!hi->report)
@@ -145,14 +143,9 @@ static int uclogic_input_configured(stru
break;
}

- if (suffix) {
- len = strlen(hdev->name) + 2 + strlen(suffix);
- name = devm_kzalloc(&hi->input->dev, len, GFP_KERNEL);
- if (name) {
- snprintf(name, len, "%s %s", hdev->name, suffix);
- hi->input->name = name;
- }
- }
+ if (suffix)
+ hi->input->name = devm_kasprintf(&hdev->dev, GFP_KERNEL,
+ "%s %s", hdev->name, suffix);

return 0;
}