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 36D6E1D7995; Tue, 16 Jun 2026 15:05:06 +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=1781622307; cv=none; b=ruv6nf9nxSiAYlRy5HoLI0Ww1nSIofcCojuB93/18zpFK7YrwqwRk+I5OH9TlfKY5z8BnnWekgoxVaE2KRhc+se7NJOSQvi4KE1ZwdKEjnH86iA9EhItjCP9c5peHtGVoen0KZ1dCnyZ/rE69yqlIbGpaMhowDvGlQYseAopmJ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781622307; c=relaxed/simple; bh=lCjkGqH+/Lay5HK4uzw1LAHc8Wq5d5YdmIoQiqb3qok=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d11HkGjOy/wpSjxDThAEFGmYYqtt9bU3BtF3iIg2zCuSRHVqjRSbomzPlV7jVsA3uucOsujxjnvUyVJ2aD4WEoeeo9wQIHp/bRqZn+dIo6g6OL/TTMmm3Q+ikv7XDWFW10jCChPubiqxO+xwlClfrjnLLJuk2OaRihI3Aheceso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tUfqpuUy; 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="tUfqpuUy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41BB71F000E9; Tue, 16 Jun 2026 15:05:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781622306; bh=MpqnLX98evRFE7q9jzh7jcCrYLR17q+Q3sUxYIgb/lY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tUfqpuUysWuFIAFsudZbd15cNJd2RI6UuKFCprn8gyxvga2FKSE19kWN1kqGA2Kby oroDzbUDTrEUNlfj5ZpWxd6Gi8Lf6C40N4UtiHtFwYfJ498VdbFGQgH5UPlH074kE4 hIKkko2V/nUQPb35HHEJBHytdPnnpX0KPpnQe1mk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Johan Hovold , Sasha Levin Subject: [PATCH 6.12 002/261] USB: serial: mct_u232: fix memory corruption with small endpoint Date: Tue, 16 Jun 2026 20:27:20 +0530 Message-ID: <20260616145045.116421420@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145044.869532709@linuxfoundation.org> References: <20260616145044.869532709@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 915b36d701950503c4ea0f6e314b10868e59fce3 upstream. The driver overrides the maximum transfer size for a specific device which only accepts 16 byte packets for its 32 byte bulk-out endpoint. Make sure to never increase the maximum transfer size to prevent slab corruption should a malicious device report a smaller endpoint max packet size than expected. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Sasha Levin --- drivers/usb/serial/mct_u232.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c index d225d7c1455f4f..33d4bbc461be6a 100644 --- a/drivers/usb/serial/mct_u232.c +++ b/drivers/usb/serial/mct_u232.c @@ -378,6 +378,7 @@ static int mct_u232_port_probe(struct usb_serial_port *port) { struct usb_serial *serial = port->serial; struct mct_u232_private *priv; + u16 pid; /* check first to simplify error handling */ if (!serial->port[1] || !serial->port[1]->interrupt_in_urb) { @@ -385,6 +386,16 @@ static int mct_u232_port_probe(struct usb_serial_port *port) return -ENODEV; } + /* + * Compensate for a hardware bug: although the Sitecom U232-P25 + * device reports a maximum output packet size of 32 bytes, + * it seems to be able to accept only 16 bytes (and that's what + * SniffUSB says too...) + */ + pid = le16_to_cpu(serial->dev->descriptor.idProduct); + if (pid == MCT_U232_SITECOM_PID) + port->bulk_out_size = min(16, port->bulk_out_size); + priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; @@ -410,7 +421,6 @@ static void mct_u232_port_remove(struct usb_serial_port *port) static int mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port) { - struct usb_serial *serial = port->serial; struct mct_u232_private *priv = usb_get_serial_port_data(port); int retval = 0; unsigned int control_state; @@ -418,15 +428,6 @@ static int mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port) unsigned char last_lcr; unsigned char last_msr; - /* Compensate for a hardware bug: although the Sitecom U232-P25 - * device reports a maximum output packet size of 32 bytes, - * it seems to be able to accept only 16 bytes (and that's what - * SniffUSB says too...) - */ - if (le16_to_cpu(serial->dev->descriptor.idProduct) - == MCT_U232_SITECOM_PID) - port->bulk_out_size = 16; - /* Do a defined restart: the normal serial device seems to * always turn on DTR and RTS here, so do the same. I'm not * sure if this is really necessary. But it should not harm -- 2.53.0