From 27b376b945c0aac46fcdfcc950b14a85b874b557 Mon Sep 17 00:00:00 2001 From: Ibrahim Hashimov Date: Wed, 15 Jul 2026 13:52:53 +0200 Subject: [PATCH] HID: nintendo: fix out-of-bounds read in joycon_ctlr_read_handler() joycon_ctlr_read_handler() casts an incoming HID input report to struct joycon_input_report and parses it, guarding the cast only with a 12-byte length check: if (size >= 12) /* make sure it contains the input report */ joycon_parse_report(ctlr, (struct joycon_input_report *)data); struct joycon_input_report is 49 bytes: a 13-byte header followed by a union whose IMU arm is 36 bytes. For an IMU report joycon_parse_report() -> joycon_parse_imu_report() walks that union (struct offsets 13..48), so a report of exactly 12 bytes with data[0] == JC_INPUT_IMU_DATA passes the guard yet is read up to 37 bytes past its declared length. The over-read bytes are decoded into accelerometer/gyroscope values and forwarded to userspace through the "(IMU)" input device, leaking driver-internal memory. data[0] and size are fully controlled by a malicious or spoofed Joy-Con/Pro Controller. Receive buffers are sized to the maximum report length, so this is an over-read within the allocation rather than a slab OOB, but the decoded bytes still reach userspace. The sibling subcmd path in joycon_ctlr_handle_event() already bounds the same cast correctly: if (size < sizeof(struct joycon_input_report) || data[0] != JC_INPUT_SUBCMD_REPLY) break; Use the same sizeof(struct joycon_input_report) bound here. Fixes: 2af16c1f846b ("HID: nintendo: add nintendo switch controller driver") Cc: stable@vger.kernel.org Signed-off-by: Ibrahim Hashimov Assisted-by: AuditCode-AI:2026.07 Reviewed-by: Silvan Jegen Signed-off-by: Jiri Kosina --- drivers/hid/hid-nintendo.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c index 0db553528826..99bfa6a12096 100644 --- a/drivers/hid/hid-nintendo.c +++ b/drivers/hid/hid-nintendo.c @@ -2607,7 +2607,12 @@ static int joycon_ctlr_read_handler(struct joycon_ctlr *ctlr, u8 *data, { if (data[0] == JC_INPUT_SUBCMD_REPLY || data[0] == JC_INPUT_IMU_DATA || data[0] == JC_INPUT_MCU_DATA) { - if (size >= 12) /* make sure it contains the input report */ + /* + * The whole struct is cast and parsed below, including the + * IMU/subcmd union, not just the 12-byte partial header this + * used to check for. + */ + if (size >= sizeof(struct joycon_input_report)) joycon_parse_report(ctlr, (struct joycon_input_report *)data); }