From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50803) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cDy8c-0006EL-T8 for qemu-devel@nongnu.org; Mon, 05 Dec 2016 13:37:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cDy8a-0007kV-BH for qemu-devel@nongnu.org; Mon, 05 Dec 2016 13:37:18 -0500 Received: from mail-by2nam01on0083.outbound.protection.outlook.com ([104.47.34.83]:20512 helo=NAM01-BY2-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cDy8Z-0007k7-Ty for qemu-devel@nongnu.org; Mon, 05 Dec 2016 13:37:16 -0500 From: Alistair Francis Date: Mon, 5 Dec 2016 10:35:26 -0800 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH for 2.8 v3 1/1] cadence_uart: Check baud rate generator and divider values on migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, peter.maydell@linaro.org Cc: alistair.francis@xilinx.com, alistair23@gmail.com, pjp@fedoraproject.org, psirt@huawei.com The Cadence UART device emulator calculates speed by dividing the baud rate by a 'baud rate generator' & 'baud rate divider' value. The device specification defines these register values to be non-zero and within certain limits. Checks were recently added when writing to these registers but not when restoring from migration. This patch adds checks when restoring from migration to avoid divide by zero errors. Reported-by: Huawei PSIRT Signed-off-by: Alistair Francis --- It would be nice to squeeze this into 2.8 if possible. V3: - Fix broken migration logic - Manually double checked and it passes migration. V2: - Abort the migration if the data is invalid hw/char/cadence_uart.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c index 0215d65..ce9063b 100644 --- a/hw/char/cadence_uart.c +++ b/hw/char/cadence_uart.c @@ -502,6 +502,13 @@ static int cadence_uart_post_load(void *opaque, int version_id) { CadenceUARTState *s = opaque; + /* Ensure these two aren't invalid numbers */ + if (s->r[R_BRGR] <= 1 || s->r[R_BRGR] & ~0xFFFF || + s->r[R_BDIV] <= 3 || s->r[R_BDIV] & ~0xFF) { + /* Value is invalid, abort */ + return 1; + } + uart_parameters_setup(s); uart_update_status(s); return 0; -- 2.7.4