From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 744EE42BC31; Wed, 15 Jul 2026 08:37:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784104681; cv=none; b=u26zAQkkO7caF8Rc1otbnGN81DYtTRrIXZwoHqiqVfv8ds3q8MReH/JZnXALBtKM24+C8D9aRyB6Z9F0LYfwq2WGmsvHcx5uiLVry8iBCrlb57YcAPwHqcru21q9wgO4kkkmkk0Z42pCYLAX2L9Pt/+JMNmmeGcLkm/lEnQwLtY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784104681; c=relaxed/simple; bh=x2V74GwFV4oWQrLG9v54s8LtJx1hg9zc1oQefQ4YSgQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=txxNtV129/CzxcqJauWPKPrh31XjuYmorRF5VJaydNTqjkXL5Jyl39dJ032reQETSejFhVaO3targKYP1wHgHoUOopNBzEo9BRwYY6mYuG8OWVPUPqBM683T+5ridbGicCqyUgLknx9/Qe9tLNeeRgpbsbmdEw5hbiB6UjNJUC8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from localhost.localdomain (unknown [111.196.245.140]) by APP-05 (Coremail) with SMTP id zQCowADnL8PiRldqg1ZHGA--.14945S2; Wed, 15 Jul 2026 16:37:54 +0800 (CST) From: Pengpeng Hou To: Rishi Gupta Cc: Pengpeng Hou , Jiri Kosina , Benjamin Tissoires , linux-i2c@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] HID: mcp2221: validate raw report length Date: Wed, 15 Jul 2026 16:37:54 +0800 Message-ID: <20260715083754.31210-1-pengpeng@iscas.ac.cn> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:zQCowADnL8PiRldqg1ZHGA--.14945S2 X-Coremail-Antispam: 1UD129KBjvJXoW7KrWUurW5ZrWrZrW3tFy7Jrb_yoW8XFyrpF Wqq390yryUtr42qwnxCw1DJa4Yq3WfJFsrCF9Fg3WUua15Kw15AryFgFyvvrW5ZF48Kr93 XF4FqFZ3GFyjkaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkK14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26F4UJVW0owA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_JF0_Jw1lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7CjxVAaw2AFwI0_ JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67 AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIY rxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14 v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_ Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUbknY7 UUUUU== X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ HID calls a driver raw_event() callback before it performs the generic report-length validation. mcp2221_raw_event() subsequently reads fixed response fields up to byte 55 and can copy a response payload through byte 63. A short input report can therefore be interpreted using bytes beyond the current report length before the HID core rejects it. Validate the descriptor-derived report length at the beginning of the driver callback. Complete the pending command with -EINVAL for a truncated report so that a malformed response does not turn into an unrelated timeout. Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Signed-off-by: Pengpeng Hou --- drivers/hid/hid-mcp2221.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index e4ddd8e9293b..67afef1a275f 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -861,6 +861,17 @@ static int mcp2221_raw_event(struct hid_device *hdev, u8 *buf; struct mcp2221 *mcp = hid_get_drvdata(hdev); + /* + * HID invokes .raw_event() before its generic report-length check. + * The response handlers below read fixed offsets from @data, so reject + * a truncated current report before interpreting any of its fields. + */ + if (size < hid_report_len(report)) { + mcp->status = -EINVAL; + complete(&mcp->wait_in_report); + return 1; + } + switch (data[0]) { case MCP2221_I2C_WR_DATA: -- 2.43.0