This is a note to let you know that I've just added the patch titled usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usbip-fix-stub_rx-harden-cmd_submit-path-to-handle-malicious-input.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c6688ef9f29762e65bce325ef4acd6c675806366 Mon Sep 17 00:00:00 2001 From: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Date: Thu, 7 Dec 2017 14:16:48 -0700 Subject: usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input From: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> commit c6688ef9f29762e65bce325ef4acd6c675806366 upstream. 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@xxxxxxxxxxx> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/usbip/stub_rx.c | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) --- a/drivers/usb/usbip/stub_rx.c +++ b/drivers/usb/usbip/stub_rx.c @@ -338,11 +338,13 @@ static struct stub_priv *stub_priv_alloc return priv; } -static int get_pipe(struct stub_device *sdev, int epnum, int dir) +static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu) { struct usb_device *udev = sdev->udev; struct usb_host_endpoint *ep; struct usb_endpoint_descriptor *epd = NULL; + int epnum = pdu->base.ep; + int dir = pdu->base.direction; if (epnum < 0 || epnum > 15) goto err_ret; @@ -355,6 +357,7 @@ static int get_pipe(struct stub_device * goto err_ret; epd = &ep->desc; + if (usb_endpoint_xfer_control(epd)) { if (dir == USBIP_DIR_OUT) return usb_sndctrlpipe(udev, epnum); @@ -377,6 +380,27 @@ static int get_pipe(struct stub_device * } if (usb_endpoint_xfer_isoc(epd)) { + /* validate packet size and number of packets */ + unsigned int maxp, packets, bytes; + +#define USB_EP_MAXP_MULT_SHIFT 11 +#define USB_EP_MAXP_MULT_MASK (3 << USB_EP_MAXP_MULT_SHIFT) +#define USB_EP_MAXP_MULT(m) \ + (((m) & USB_EP_MAXP_MULT_MASK) >> USB_EP_MAXP_MULT_SHIFT) + + maxp = usb_endpoint_maxp(epd); + maxp *= (USB_EP_MAXP_MULT( + __le16_to_cpu(epd->wMaxPacketSize)) + 1); + bytes = pdu->u.cmd_submit.transfer_buffer_length; + packets = DIV_ROUND_UP(bytes, maxp); + + if (pdu->u.cmd_submit.number_of_packets < 0 || + pdu->u.cmd_submit.number_of_packets > packets) { + dev_err(&sdev->udev->dev, + "CMD_SUBMIT: isoc invalid num packets %d\n", + pdu->u.cmd_submit.number_of_packets); + return -1; + } if (dir == USBIP_DIR_OUT) return usb_sndisocpipe(udev, epnum); else @@ -385,7 +409,7 @@ static int get_pipe(struct stub_device * err_ret: /* NOT REACHED */ - dev_err(&sdev->udev->dev, "get pipe() invalid epnum %d\n", epnum); + dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum); return -1; } @@ -450,7 +474,7 @@ static void stub_recv_cmd_submit(struct struct stub_priv *priv; struct usbip_device *ud = &sdev->ud; struct usb_device *udev = sdev->udev; - int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction); + int pipe = get_pipe(sdev, pdu); if (pipe == -1) return; Patches currently in stable-queue which might be from shuahkh@xxxxxxxxxxxxxxx are queue-4.4/usbip-fix-stub_rx-harden-cmd_submit-path-to-handle-malicious-input.patch queue-4.4/usbip-fix-potential-format-overflow-in-userspace-tools.patch queue-4.4/usbip-fix-implicit-fallthrough-warning.patch queue-4.4/usbip-prevent-leaking-socket-pointer-address-in-messages.patch queue-4.4/usbip-fix-stub_rx-get_pipe-to-validate-endpoint-number.patch queue-4.4/usbip-prevent-vhci_hcd-driver-from-leaking-a-socket-pointer-address.patch queue-4.4/usb-usbip-fix-possible-deadlocks-reported-by-lockdep.patch