Re: [patch] hid2hci check usb_init return value

Khem Raj
2008-12-30T06:26:56Z

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On (29/12/08 13:12), Marcel Holtmann wrote:
> Hi Khem,
>
> > Working on a system which did not have a USB in it. I was getting a
> > segfault with hid2hci. The problem tracked down was usb_init () was
> > failing and we did not check for it and carried on with execution.
> > As a result the next call to libusb failed because we passed in NULL for
> > ctx because during usb_init () this should have been malloc'ed if all
> > have gone correctly but in case of error usb_init () free's up the
> > allocated memory and hence the segfault.
> >
> > We should check for return value of usb_init () call and exit
> > immediately if it fails. Tested on 4.24 release.
>
> the problem is that usb_init() doesn't return any errors on the versions
> that I have here:
>
> ii libusb-0.1-4 2:0.1.12-12 userspace USB programming library
> ii libusb-dev 2:0.1.12-12 userspace USB programming library
>
> Applying your patch would break complication on multiple platforms.
What you have is libusb-0.1 which has older API I suppose. There is
libusb-compat which can be used as a wrapper over libusb1 to give
libusb0 like interfaces.

Actually I was using libusb-1.0.0 API as mentioned here
http://libusb.sourceforge.net/api-1.0/group__lib.html
that also means that the patch I attached should have been using
libusb_init() instead.

Here is updated patch

Thanks

-Khem

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# Signed-off-by: Khem Raj <raj.khem@gmail.com>
#
# Use the new usb1 API for usb_init() and check for fails from
# usb_init (). Currently we see a crash on a system which does
# not have USB because usb_init() fails and it cleans up all initialized
# data (e.g. ctx) which is used in subsequent calls to libusb
# We return immediately if usb_init() fails for some reason.

Index: bluez-4.24/tools/hid2hci.c
===================================================================
--- bluez-4.24.orig/tools/hid2hci.c 2008-10-25 23:40:34.000000000 -0700
+++ bluez-4.24/tools/hid2hci.c 2008-12-29 22:06:04.000000000 -0800
@@ -337,7 +337,7 @@
int main(int argc, char *argv[])
{
struct device_info dev[16];
- int i, opt, num, quiet = 0, mode = HCI;
+ int i, ret, opt, num, quiet = 0, mode = HCI;

while ((opt = getopt_long(argc, argv, "+01qh", main_options, NULL)) != -1) {
switch (opt) {
@@ -361,8 +361,9 @@
argc -= optind;
argv += optind;
optind = 0;
-
- usb_init();
+ ret = libusb_init();
+ if (ret < 0)
+ return ret;

num = find_devices(mode, dev, sizeof(dev) / sizeof(dev[0]));
if (num <= 0) {