[PATCH] USB: coverity: (desc->bitmap)[] overrun fix

The length of the array desc->bitmap is 3, and not 4:

Definitions involved:

In drivers/usb/core/hcd.h

464  	#define bitmap 	DeviceRemovable

In drivers/usb/host/ohci-hub.c

395  		struct usb_hub_descriptor	*desc

In drivers/usb/core/hub.h

130  	struct usb_hub_descriptor {
131  		__u8  bDescLength;
132  		__u8  bDescriptorType;
133  		__u8  bNbrPorts;
134  		__u16 wHubCharacteristics;
135  		__u8  bPwrOn2PwrGood;
136  		__u8  bHubContrCurrent;
137  		    	/* add 1 bit for hub status change; round to bytes */
138  		__u8  DeviceRemovable[(USB_MAXCHILDREN + 1 + 7) / 8];
139  		__u8  PortPwrCtrlMask[(USB_MAXCHILDREN + 1 + 7) / 8];
140  	} __attribute__ ((packed));

In include/linux/usb.h

306  	#define USB_MAXCHILDREN		(16)

This defect was found automatically by Coverity Prevent, a static analysis
tool.

(akpm: this code should be shot.  Field `bitmap' doesn't exist in struct
usb_hub_descriptor.  And this .c file is #included in
drivers/usb/host/ohci-hcd.c, and someone somewhere #defines `bitmap' to
`DeviceRemovable'.

>From a maintainability POV it would be better to memset the whole array
beforehand - I changed the patch to do that)

Signed-off-by: Zaur Kambarov <zkambarov@coverity.com>
Cc: <linux-usb-devel@lists.sourceforge.net?
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c
index e2fc4129dfc6e0f3684d3d5aee438ca4a0e85640..83ca4549a50ecac5f82504ba375419ad3c9b6d0a 100644 (file)
--- a/drivers/usb/host/ohci-hub.c
+++ b/drivers/usb/host/ohci-hub.c
@@ -419,10 +419,11 @@ ohci_hub_descriptor (
 
        /* two bitmaps:  ports removable, and usb 1.0 legacy PortPwrCtrlMask */
        rh = roothub_b (ohci);
+       memset(desc->bitmap, 0xff, sizeof(desc->bitmap));
        desc->bitmap [0] = rh & RH_B_DR;
        if (ports > 7) {
                desc->bitmap [1] = (rh & RH_B_DR) >> 8;
-               desc->bitmap [2] = desc->bitmap [3] = 0xff;
+               desc->bitmap [2] = 0xff;
        } else
                desc->bitmap [1] = 0xff;
 }