usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input
Harden CMD_SUBMIT path to handle malicious input that could trigger large memory allocations. Add checks to validate transfer_buffer_length and number_of_packets to protect against bad input requesting for unbounded memory allocations. Validate early in get_pipe() and return failure. Reported-by: Secunia Research <vuln@secunia.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -322,11 +322,13 @@ static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
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return priv;
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}
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static int get_pipe(struct stub_device *sdev, int epnum, int dir)
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static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu)
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{
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struct usb_device *udev = sdev->udev;
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struct usb_host_endpoint *ep;
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struct usb_endpoint_descriptor *epd = NULL;
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int epnum = pdu->base.ep;
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int dir = pdu->base.direction;
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if (epnum < 0 || epnum > 15)
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goto err_ret;
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@ -339,6 +341,15 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
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goto err_ret;
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epd = &ep->desc;
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/* validate transfer_buffer_length */
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if (pdu->u.cmd_submit.transfer_buffer_length > INT_MAX) {
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dev_err(&sdev->udev->dev,
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"CMD_SUBMIT: -EMSGSIZE transfer_buffer_length %d\n",
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pdu->u.cmd_submit.transfer_buffer_length);
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return -1;
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}
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if (usb_endpoint_xfer_control(epd)) {
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if (dir == USBIP_DIR_OUT)
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return usb_sndctrlpipe(udev, epnum);
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@ -361,6 +372,21 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
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}
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if (usb_endpoint_xfer_isoc(epd)) {
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/* validate packet size and number of packets */
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unsigned int maxp, packets, bytes;
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maxp = usb_endpoint_maxp(epd);
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maxp *= usb_endpoint_maxp_mult(epd);
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bytes = pdu->u.cmd_submit.transfer_buffer_length;
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packets = DIV_ROUND_UP(bytes, maxp);
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if (pdu->u.cmd_submit.number_of_packets < 0 ||
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pdu->u.cmd_submit.number_of_packets > packets) {
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dev_err(&sdev->udev->dev,
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"CMD_SUBMIT: isoc invalid num packets %d\n",
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pdu->u.cmd_submit.number_of_packets);
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return -1;
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}
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if (dir == USBIP_DIR_OUT)
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return usb_sndisocpipe(udev, epnum);
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else
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@ -369,7 +395,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
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err_ret:
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/* NOT REACHED */
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dev_err(&sdev->udev->dev, "get pipe() invalid epnum %d\n", epnum);
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dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum);
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return -1;
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}
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@ -434,7 +460,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
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struct stub_priv *priv;
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struct usbip_device *ud = &sdev->ud;
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struct usb_device *udev = sdev->udev;
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int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction);
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int pipe = get_pipe(sdev, pdu);
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if (pipe == -1)
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return;
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@ -456,7 +482,8 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
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}
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/* allocate urb transfer buffer, if needed */
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if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
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if (pdu->u.cmd_submit.transfer_buffer_length > 0 &&
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pdu->u.cmd_submit.transfer_buffer_length <= INT_MAX) {
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priv->urb->transfer_buffer =
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kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
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GFP_KERNEL);
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