Segmentation fault in eglibc if usbfs_path is NULL and usbfs_get_device_list get called afterwards

[Unknown | zD.]

Basically this bug exist from 1.0.12 to 1.0.16 (so this may affect Saucy as well)

Tested under Hyper-V Ubuntu 13.04 (Raring) with linux-virtual kernel and targeted driver (using netinstall iso).

So I have got this bug when I was running the steam client binary (yes, I know that this may also be a problem created by steam client itself as it ignores the value returned by op_init, but I think it would be to make the libusbx to become a fail proof library. And I will report this bug to valve as well) in Hyper VM (Raring), without any predefined usbfs path on it.

As there is no dbg build for libusb-1.0.12 atm, I have built one on my own and here is what I have got with gdb attached to steam client binary.
-------------------------------------------------------------------------------------------------------------------------------------------
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xecf00b40 (LWP 40013)]
__opendirat (dfd=dfd@entry=-100, name=name@entry=0x0)
    at ../sysdeps/posix/opendir.c:90
90 ../sysdeps/posix/opendir.c: No such file or directory.
(gdb) frame 2
#2 0xec2e460e in usbfs_get_device_list (_discdevs=0xeceffddc, ctx=0xebd014c8)
    at os/linux_usbfs.c:1088
1088 DIR *buses = opendir(usbfs_path);
-------------------------------------------------------------------------------------------------------------------------------------------
(Frame 1 is simply a opendir function which passed the NULL pointer to opendirat in eglibc)

Afterwards, I have recompiled the libusb 1.0.12 with following lines added to the usbfs_get_device_list function.
-------------------------------------------------------------------------------------------------------------------------------------------
static int usbfs_get_device_list(struct libusb_context *ctx,
 struct discovered_devs **_discdevs)
{
 if (!usbfs_path) {
  usbi_err(ctx, "could not find usbfs");
  return LIBUSB_ERROR_OTHER;
 }
 struct dirent *entry;
 DIR *buses = opendir(usbfs_path);
-------------------------------------------------------------------------------------------------------------------------------------------
And steam client is working like a charm again.

Therefore I want to ask can you guys consider to add a check within usbfs_get_device_list or not?

Best regards,
UnknownzD

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.