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 030B03BB113 for ; Mon, 7 Sep 2026 22:12:43 +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=1788819165; cv=none; b=gesmsKTAiieq4SIzhPgRBGBrHCRsoTkkaDEzx2deQUu0EJZIf+LSCFZIv0C9C2MMTm7E94jKktzoj/Ed643wV07gECINA7ReEqIwyKEUxa65wktP0ioS8v3v8j6xv42qZLoRmuuYQDBzWoahV6V7aFKJuOWh/pG1sFNO/I0yIMI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788819165; c=relaxed/simple; bh=tugY/PAXEYwGPWERXaK/QV/fN5HAPMBg+EUlT+9EDhc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kqnY3sZnSt5WcusDe4pvvYJ4K5gORRB2zrUGxP6WfxbSP6VuxpKikbMcX/YUMREm8zvfmiLB0V4fbplsUkAeV3C8LtKzwLxUPJEqwpo3fPrR0ZH6YaV7RPailwm9kxIOXcwCgEM5pUELtABd/Tou6L4L6usFDOcWKbAtzcQPwME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LWGIHS7G; 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="LWGIHS7G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07B601F00A3A; Mon, 7 Sep 2026 22:12:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788819163; bh=Qkt2UfqpD1xhjC7Ina8fvjdMSKUjW+nDfFd6840eah0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LWGIHS7GzWW5iGWjD0MsvxNAlW9q0zabtyTRCHJw5Z4kkN92rYj1uHe0dQ/njP5Zu 82BMWA1v8TMroHSIqX3rvV/25lZmCiL4S51xSpIHx7kgoZhy2QIOKncAIBtfPysJAo JJNxfsL1WaE6LqHA6wt71RoYJdEsAWHVBJXBAPArlbmhfUCdEwSwegiD9RaIopu1pD fSBAfNAhFZViTjHVdTiLGWObWSafKgvILjwAllBcekcZSKcKC4stmKtqmyeRHI1VAn P+Qsnheb3ebtmk7L3sqNeuc10NRjk/hxsvhvlZARYMTXm8NlkY74yT1/izdEN2BPIy Wbem4lF+Ye3Tw== From: Sasha Levin To: stable@vger.kernel.org Cc: Florian Pradines , =?UTF-8?q?Beno=C3=AEt=20Sevens?= , Jiri Kosina , Sasha Levin Subject: [PATCH 5.15.y 1/2] HID: mcp2221: fix OOB write in mcp2221_raw_event() Date: Mon, 7 Sep 2026 18:12:40 -0400 Message-ID: <20260907221241.650068-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090357-unleash-dimple-e652@gregkh> References: <2026090357-unleash-dimple-e652@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 9fb98c8e1ffb7..239efb89490f9 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -93,6 +93,7 @@ struct mcp2221 { u8 *rxbuf; u8 txbuf[64]; int rxbuf_idx; + int rxbuf_size; int status; u8 cur_i2c_clk_div; struct gpio_chip *gc; @@ -289,12 +290,14 @@ 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); @@ -797,6 +800,10 @@ 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; + } buf = mcp->rxbuf; memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]); mcp->rxbuf_idx = mcp->rxbuf_idx + data[3]; -- 2.53.0