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 E995143C05B for ; Mon, 7 Sep 2026 21:36:35 +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=1788816997; cv=none; b=uBqXQ3WnSPFfRRjfElL9VYmfhfcqkw7TibfPjZ8A9Uirggp4lcBBCguCkuGm5Zv1skYf95B3+eHPbiE3CSIEIienj2lMOIFwf0jL7aqgFh4mCLfM29K+Ly0CmTiNyrS/TmYcuNyfHDKV4p0pPTX27+kAd091Ds49frGmg4ze1Qc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788816997; c=relaxed/simple; bh=0R0TVuFBg91URqgEUWMh0tR+UL1GaNk8ZXMTWNcXv2s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=WQQXHmjKAy8h7I0BfYMvpplkaMMLRezJepvYRryyewNpWHICTa5tZcJ1zBv6LczmN181J95/nYKQKVyvUZ+w4VYgPhuBPiXaS/e/RkvcocEK+PWXXdLT/6vtDaOYjhyj9987bAVPwyLkhwoLse8/hAWO31jG8GRf/GcQKsQlJSI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O+t/SLDa; 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="O+t/SLDa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BFD61F00A3A; Mon, 7 Sep 2026 21:36:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788816995; bh=CcR4AGmL45PyAOUSUUykifd2WG1Tt1sxxuacvvHKoZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=O+t/SLDauYJKUb/h8FWOOwHj8JRyjGr4jLKxO4sADBduR4q/zU1lePAqNU5N9ZWJT JgbPQNobBvgk9PIuRoE7od1tz2UkyJiZz02CQ1aSVnvC//y6KNCaOCuYA9JqYIByaD 9z9dmRVG2s1kzAGZhDHLZDf6WLIgxqStYfZN6l8lnp6wQ7ChVteGyaX5AaoxvJ2yvP eFf21x4bdCQda/D9GfopBHjZKrsbTdpqp24q5aqSzd/NYQa2B7zGNeYKxYZgIsMn17 DJa2BjieNEC6gPUMZgzELl8Q0MnRuyD8zAA7537VOsBHJVpSOtDBSkOtqia4r9HuuE zftgE2VzV83/Q== From: Sasha Levin To: stable@vger.kernel.org Cc: Florian Pradines , =?UTF-8?q?Beno=C3=AEt=20Sevens?= , Jiri Kosina , Sasha Levin Subject: [PATCH 6.18.y 1/2] HID: mcp2221: fix OOB write in mcp2221_raw_event() Date: Mon, 7 Sep 2026 17:36:32 -0400 Message-ID: <20260907213633.573900-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090356-tusk-brunt-33b1@gregkh> References: <2026090356-tusk-brunt-33b1@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 faebe95b4eb04..a33f33c33d768 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -121,6 +121,7 @@ struct mcp2221 { u8 *rxbuf; u8 txbuf[64]; int rxbuf_idx; + int rxbuf_size; int status; u8 cur_i2c_clk_div; struct gpio_chip *gc; @@ -323,12 +324,14 @@ 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); @@ -915,6 +918,10 @@ 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