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 E08C847F3CB; Sat, 12 Sep 2026 13:33:17 +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=1789220001; cv=none; b=gWECYKateYBoAj8o/ym1Fy2R4UHDCeGIEa2L5iMQEIXjYc4OP8Ycqx+dj2jFKoV0twLWdSv2ZGtOqA4SPvlJ6sxBG6bCJhymnipboUGqd6aMZ/czk+3JUUZWpK4EtYBKZ/o2Sbx6LcphpcLXyA8DqOz+JUpk/LTluGIjL8d+zkI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789220001; c=relaxed/simple; bh=XEWvGvE75iVIW2B8fr2WBNZ9smvytXFHdeH8OSTlbcg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mTs0Hz+5t0rk2WnSGD9xYSVQy+NYJA2E9ZSTLj4JOH4/1s4XifIcXMP2PHLLuhfKqycxEZDHm2cSLP8J2mndAu2KssBw9pTegMsKOhX3b/eKouQkJySCy6Pz+dC9nDUurb6r09TebDMdOO5doAu88dn+aEVg/Tm4qEOyQQziXbg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GCsbPupn; 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="GCsbPupn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89E891F000FF; Sat, 12 Sep 2026 13:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789219997; bh=3yUQakrtN7czjS4xLeHfkQX/fb8ua6m7KopUrURgWsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GCsbPupnYEfnoHknhrI98nWKO8tOmMZQVqAYi3/s/YE3xsjgIVRMec94zuaXHfLhN 73VVUFFO2PHmMqRkl0feXrVfM4Qs4nZs8oQOiLX/kxhZx4xOqggT+pCUVIAfry2swY yPIf45ieLyTZbVG+3iLDVadbXTrROsfaU9hMowjI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiangshan Yi , Jiri Kosina Subject: [PATCH 6.6 0088/1424] HID: mcp2221: validate report size in mcp2221_raw_event() Date: Sat, 12 Sep 2026 08:42:00 +0200 Message-ID: <20260912065609.276287354@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@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 6.6-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 @@ -759,6 +759,9 @@ 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: @@ -820,6 +823,10 @@ 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];