[PATCH] USB: coverity: (desc->bitmap)[] overrun fix
KAMBAROV, ZAUR [Sat, 25 Jun 2005 05:20:35 +0000 (22:20 -0700)]
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>

drivers/usb/host/ohci-hub.c

index e2fc412..83ca454 100644 (file)
@@ -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;
 }