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xhci: Limit roothub ports to 15 USB3 & 31 USB2 ports. 

The USB core allocates a USB 2.0 roothub descriptor that has room for 31
(USB_MAXCHILDREN) ports' worth of DeviceRemovable and PortPwrCtrlMask
fields.  Limit the number of USB 2.0 roothub ports accordingly.  I don't
expect to run into this limitation ever, but this prevents a buffer
overflow issue in the roothub descriptor filling code.

Similarly, a USB 3.0 hub can only have 15 downstream ports, so limit the
USB 3.0 roothub to 15 USB 3.0 ports.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This commit is contained in:
Sarah Sharp 2010-11-23 10:42:22 -08:00
parent 4bbb0ace9a
commit d30b2a2081
1 changed files with 18 additions and 0 deletions
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18
drivers/usb/host/xhci-mem.c
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@ -1803,6 +1803,20 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
} }
xhci_dbg(xhci, "Found %u USB 2.0 ports and %u USB 3.0 ports.\n", xhci_dbg(xhci, "Found %u USB 2.0 ports and %u USB 3.0 ports.\n",
xhci->num_usb2_ports, xhci->num_usb3_ports); xhci->num_usb2_ports, xhci->num_usb3_ports);
/* Place limits on the number of roothub ports so that the hub
* descriptors aren't longer than the USB core will allocate.
*/
if (xhci->num_usb3_ports > 15) {
xhci_dbg(xhci, "Limiting USB 3.0 roothub ports to 15.\n");
xhci->num_usb3_ports = 15;
}
if (xhci->num_usb2_ports > USB_MAXCHILDREN) {
xhci_dbg(xhci, "Limiting USB 2.0 roothub ports to %u.\n",
USB_MAXCHILDREN);
xhci->num_usb2_ports = USB_MAXCHILDREN;
}
/* /*
* Note we could have all USB 3.0 ports, or all USB 2.0 ports. * Note we could have all USB 3.0 ports, or all USB 2.0 ports.
* Not sure how the USB core will handle a hub with no ports... * Not sure how the USB core will handle a hub with no ports...
@ -1827,6 +1841,8 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
"addr = %p\n", i, "addr = %p\n", i,
xhci->usb2_ports[port_index]); xhci->usb2_ports[port_index]);
port_index++; port_index++;
if (port_index == xhci->num_usb2_ports)
break;
} }
} }
if (xhci->num_usb3_ports) { if (xhci->num_usb3_ports) {
@ -1845,6 +1861,8 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
"addr = %p\n", i, "addr = %p\n", i,
xhci->usb3_ports[port_index]); xhci->usb3_ports[port_index]);
port_index++; port_index++;
if (port_index == xhci->num_usb3_ports)
break;
} }
} }
return 0; return 0;