Skip to content

Code does not handle 0 length items contained within Configuration Descriptor. #40

Closed
@KurtE

Description

@KurtE

The code: void USBHost::parseConfDescr(USBDeviceConnected * dev, uint8_t * conf_descr, uint32_t len, IUSBEnumerator* pEnumerator)

Will hang if a device returns a descriptor, which has 0 length items...

One such device is a keyboard from GIGABYTE. I have one Force K83(might be H83)...
Whose descriptor is:

Configuration Descriptor
2400E8F0 - 09 02 54 00 03 01 00 A0  32 09 04 00 00 01 03 01  : ..T..... 2.......
2400E900 - 01 00 09 21 10 01 00 01  22 3B 00 07 05 81 03 08  : ...!.... ";......
2400E910 - 00 08 09 04 01 00 01 03  01 22 51 00 07 05 82 03  : ........ ."Q.....
2400E920 - 10 00 08 09 04 02 00 01  03 00 00 00 09 21 10 01  : ........ .....!..
2400E930 - 00 01 22 25 00 07 05 83  03 10 00 01 00 00 00 00  : .."%.... ........
2400E940 - 00 00 00 00                                       : ....

I ran into this issue on another USBHost implementation that I help support, which is why I have one of these
keyboards.

I was able to solve it in my fork/branch by adding test like:

void USBHost::parseConfDescr(USBDeviceConnected * dev, uint8_t * conf_descr, uint32_t len, IUSBEnumerator* pEnumerator)
{
    uint32_t index = 0;
    uint32_t len_desc = 0;
    uint8_t id = 0;
    int nb_endpoints_used = 0;
    USBEndpoint * ep = NULL;
    uint8_t intf_nb = 0;
    bool parsing_intf = false;
    uint8_t current_intf = 0;

    while (index < len) {
        len_desc = conf_descr[index];
        if (len_desc == 0) {
            index++;
            continue;
        }
        id = conf_descr[index+1];
...

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions