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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>
hifive-unleashed-5.1
Shuah Khan 2017-12-07 14:16:48 -07:00 committed by Greg Kroah-Hartman
parent 635f545a7e
commit c6688ef9f2
1 changed files with 31 additions and 4 deletions
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35
drivers/usb/usbip/stub_rx.c
View File

@ -322,11 +322,13 @@ static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
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;
@ -339,6 +341,15 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
goto err_ret;
epd = &ep->desc;
/* validate transfer_buffer_length */
if (pdu->u.cmd_submit.transfer_buffer_length > INT_MAX) {
dev_err(&sdev->udev->dev,
"CMD_SUBMIT: -EMSGSIZE transfer_buffer_length %d\n",
pdu->u.cmd_submit.transfer_buffer_length);
return -1;
}
if (usb_endpoint_xfer_control(epd)) {
if (dir == USBIP_DIR_OUT)
return usb_sndctrlpipe(udev, epnum);
@ -361,6 +372,21 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
}
if (usb_endpoint_xfer_isoc(epd)) {
/* validate packet size and number of packets */
unsigned int maxp, packets, bytes;
maxp = usb_endpoint_maxp(epd);
maxp *= usb_endpoint_maxp_mult(epd);
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
@ -369,7 +395,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
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;
}
@ -434,7 +460,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
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;
@ -456,7 +482,8 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
}
/* allocate urb transfer buffer, if needed */
if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
if (pdu->u.cmd_submit.transfer_buffer_length > 0 &&
pdu->u.cmd_submit.transfer_buffer_length <= INT_MAX) {
priv->urb->transfer_buffer =
kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
GFP_KERNEL);