From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B77DC278161; Sat, 12 Sep 2026 15:28:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789226906; cv=none; b=LkMxc1VmmRC0ynqidLPY+31kk2KdbtfMUhtWkow0rJvyK2g9Uez4bE+xqqbe+BQpzAynUYa7VN1+uWeH7lH2EbgSXABdxVLL8rnrFYQUZzNAhToWwDhiCNFD7bg+qDdiZs4Lv+sXviFebjaI6b+TmdCMMte9ts0fL/TxXUtY6tM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789226906; c=relaxed/simple; bh=lB/cWPaM5ZcPegr9g20uLDYzpTmzO2GmqLcARA7o8+k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WYPbYkYUda8/lB2krTfu8v7svR05v48foJVw12JepDcODEurG5WsBOh3mPddF70NdGBy8g8pee072lfLMWDAFkzbxWef46tHGpXCL1zOC1T32YwiAfwMvJc930NUn2sRYlCSfWdRLdw7oU1HoyeqkT+F45lR2D0TW5xUNzG3uXc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vElW5yXC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vElW5yXC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A253E1F000FF; Sat, 12 Sep 2026 15:28:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789226903; bh=o8vv34rgPq/WaoqdB1X3sd3FWdcYrq2CYG3/gx8DpuY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vElW5yXCG/LBAVNRoToW/fWWBYf9ggJ2nY+k6vB66nJsvhsm43qJ7TOggfO1zzJZu 6iKnezsu0XC8Lr/L2lEMxXteid80Ijdu/nsl5hsl/lDrm6hOCPk9S1OIdTR+t0HZUt 7D7QNGyBTnWnDxykBzqQ751uRqgvQYdRPpL+gDn4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiangshan Yi , Jiri Kosina Subject: [PATCH 6.1 0073/1191] HID: mcp2221: validate report size in mcp2221_raw_event() Date: Sat, 12 Sep 2026 08:46:41 +0200 Message-ID: <20260912065549.801177706@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065548.086904252@linuxfoundation.org> References: <20260912065548.086904252@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiangshan Yi commit 2c9a6998c19503626c57a2267bf279e204113079 upstream. mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy. Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Cc: stable@vger.kernel.org Signed-off-by: Jiangshan Yi Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-mcp2221.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -739,6 +739,9 @@ static int mcp2221_raw_event(struct hid_ u8 *buf; struct mcp2221 *mcp = hid_get_drvdata(hdev); + if (size < 4) + return 0; + switch (data[0]) { case MCP2221_I2C_WR_DATA: @@ -797,6 +800,10 @@ static int mcp2221_raw_event(struct hid_ mcp->status = -EINVAL; break; } + if (4 + data[3] > size) { + mcp->status = -EINVAL; + break; + } buf = mcp->rxbuf; memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]); mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];