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 C3D312F6931; Sat, 12 Sep 2026 17:04:58 +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=1789232699; cv=none; b=Uu5OqqUAUawkaNoBc32CpMLajU5QorVA0OvDdhwczax9PMskOl3+yDC3VHYPKZAdQUC8U9Ywx/pV/rX8pzeFzzjxBI+RpTFTy6pStBq3pbMomF0A/zIAClQLbSBRVHT0yCy/QSv3MlnlzqECHWf9nGZJ8hnvwwXYThMMewhmrGY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789232699; c=relaxed/simple; bh=7MkhR+tBfWnMro5q4gKP2xU95Y6Ovyj0JxbUrhV1feQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EszJ3FMXB1elYVMGtTo6pVYf89pObXyhskpTg+/aifPB05Iej3Bshp/RqTbVBwszGlzS0X5dVomLC4tWSIkVtsSEdGi8K/v3UHtF7OE5gBbEi2NJrP7abvhTIHXPEU8Jvk8E/BlK+Sp+Sqq68T3hGPAMe0BXxxbIbXugwEj3uKM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hWgDDHMo; 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="hWgDDHMo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C9AA1F000FF; Sat, 12 Sep 2026 17:04:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789232698; bh=5uY9MBkGHIt6GSFtQZLJeoxAn607XWNgSLNwbfHJApw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hWgDDHMoxGa5NzP8sRC24wkUqR1hwKQzxaMd/l2d6V5xqW9JBhpSwXslD4PaPkSKI Em4zMLsdjrE+xYogynUKCz2Biq0LLrGSNoE6/b8Uet5k8cLXE/b9JX53WzfvO9Z2VC nsSjcr7qqIsWbgbohtTWVU5YQT753KvW1yeYbGNs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiangshan Yi , Jiri Kosina Subject: [PATCH 5.15 062/935] HID: mcp2221: validate report size in mcp2221_raw_event() Date: Sat, 12 Sep 2026 08:51:32 +0200 Message-ID: <20260912065528.262231339@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@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 5.15-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];