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 74B942D5925 for ; Mon, 7 Sep 2026 21:47:47 +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=1788817668; cv=none; b=D48FslJnH+hibNwEaeZstN6GVtFbhmCXYaRI09btmeEkselPdicIdrTUPb+EfHm6eSDrj+fIln80mNuo5vrKEYvc8Ovt007nc2cK453MF2WF1Js11AaTvD3nwUOmpgvXNmMpnWfPNNtSamHdoBLfCy9Mri6sNojspAeLB+9cppI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788817668; c=relaxed/simple; bh=/9oUP/SsNXIFCB8ePTsrAI/LqABq05tKSENomlRKJCA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DVEa8RYhL6J0TyTK3ZGTSeu4P2zxR6xCuHzq0Ewz97sJZaHXz6OJTw/FpwEXBR8rdt/Pyzlo49PuggqbGMXuio4Oe9+RPQ6lITJqRFnwstjT9QyhQemYstKtlm4BDuD5IwhMbRG/b04DZSrpb+cGgMvsWxJ1LA9WgTALKRxnw4Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ekjMONio; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ekjMONio" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A7B41F00A3A; Mon, 7 Sep 2026 21:47:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788817667; bh=fm5mr+VAw6g1qVUw82pKLpdtEYN7spGrnHyqiRFJ8pg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ekjMONiopaoe/kLSyKo4FocUrjN2NVdP6sg9uWBVUoW8ZL1H68/Kaqdh8uI3ynFq1 SMOKuebTk98OQQYbMmjQ3JwBirtxYfXCz+XLTmlHcKzs6qPQJObBbWuGXUW/kEupcT RTEuRHYzyWqTnu/HxBCs/9qSyrxPvfbaF+zqDBoaBf8EkkbqpulA5zxpKN+AdYkT04 RNSrjTNLud7w/D9qdMmWFxgxXy9EgpvKl7/iY2jLQpcO7p3+Q4FWAa5s1qDO7TQWn3 hQUQHvr60Um0loG6bR+FP/N5f9wmQdlZCyaaYTfM98x0gNX8ys5Eh9IQZfH+PeqMt1 tHfVNqaQDhyOA== From: Sasha Levin To: stable@vger.kernel.org Cc: Florian Pradines , =?UTF-8?q?Beno=C3=AEt=20Sevens?= , Jiri Kosina , Sasha Levin Subject: [PATCH 6.12.y 1/2] HID: mcp2221: fix OOB write in mcp2221_raw_event() Date: Mon, 7 Sep 2026 17:47:43 -0400 Message-ID: <20260907214744.595721-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090356-sacrifice-semisoft-7d7f@gregkh> References: <2026090356-sacrifice-semisoft-7d7f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Florian Pradines [ Upstream commit f097d246677b03db814c5862f368cea341b76a00 ] mcp2221_raw_event() copies device-supplied data into mcp->rxbuf at offset rxbuf_idx without checking that the copy fits within the destination buffer. A device responding with up to 60 bytes to a small I2C/SMBus read can overflow the buffer. Add a rxbuf_size field to struct mcp2221, set it alongside rxbuf in mcp_i2c_smbus_read(), and check rxbuf_idx + data[3] <= rxbuf_size before the memcpy. Reported-by: Benoît Sevens Signed-off-by: Florian Pradines Signed-off-by: Jiri Kosina Stable-dep-of: db2333f88729 ("HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes") Signed-off-by: Sasha Levin --- drivers/hid/hid-mcp2221.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index 862ff999bb4f6..4ebdf215f3576 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -99,6 +99,7 @@ struct mcp2221 { u8 *rxbuf; u8 txbuf[64]; int rxbuf_idx; + int rxbuf_size; int status; u8 cur_i2c_clk_div; struct gpio_chip *gc; @@ -307,12 +308,14 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, mcp->txbuf[3] = (u8)(msg->addr << 1); total_len = msg->len; mcp->rxbuf = msg->buf; + mcp->rxbuf_size = msg->len; } else { mcp->txbuf[1] = smbus_len; mcp->txbuf[2] = 0; mcp->txbuf[3] = (u8)(smbus_addr << 1); total_len = smbus_len; mcp->rxbuf = smbus_buf; + mcp->rxbuf_size = smbus_len; } ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4); @@ -823,6 +826,10 @@ static int mcp2221_raw_event(struct hid_device *hdev, mcp->status = -EINVAL; break; } + if (mcp->rxbuf_idx + data[3] > mcp->rxbuf_size) { + mcp->status = -EINVAL; + break; + } if (4 + data[3] > size) { mcp->status = -EINVAL; break; -- 2.53.0