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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2010-11-23 10:42:22 -0800
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2011-03-13 18:23:42 -0700
commitd30b2a208108a0b0fdeae7006b8824d9be16ca96 (patch)
tree43df86628f31b4ad46d82258c8d8a1a8e88ae625 /drivers/usb
parent4bbb0ace9a3de8392527e3c87926309d541d3b00 (diff)
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>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/host/xhci-mem.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 180a2abbc868..71fd8bd287fe 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -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->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.
* 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,
xhci->usb2_ports[port_index]);
port_index++;
+ if (port_index == xhci->num_usb2_ports)
+ break;
}
}
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,
xhci->usb3_ports[port_index]);
port_index++;
+ if (port_index == xhci->num_usb3_ports)
+ break;
}
}
return 0;