Subject: Re: [PATCH] net/bluetooth: Fix bound check in event handling

From: Dan Carpenter <[email-masked]>
Date: Mon, 4 Mar 2019 18:04:19 +0300

Hi Tomas,

url:    https://github.com/0day-ci/linux/commits/Tomas-Bortoli/net-bluetooth-Fix-bound-check-in-event-handling/20190301-213647
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master

smatch warnings:
net/bluetooth/hci_event.c:3986 hci_inquiry_result_with_rssi_evt() warn: potential pointer math issue ('info' is a 120 bit pointer)

# https://github.com/0day-ci/linux/commit/00305742c021794f147b348d45eb10ea26e5a514
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 00305742c021794f147b348d45eb10ea26e5a514
vim +3986 net/bluetooth/hci_event.c

a9de9248 Marcel Holtmann 2007-10-20  3979  	if ((skb->len - 1) / num_rsp != sizeof(struct inquiry_info_with_rssi)) {
138d22ef Szymon Janc     2011-02-17  3980  		struct inquiry_info_with_rssi_and_pscan_mode *info;
                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

138d22ef Szymon Janc     2011-02-17  3981  		info = (void *) (skb->data + 1);
a9de9248 Marcel Holtmann 2007-10-20  3982  
e17acd40 Johan Hedberg   2011-03-30  3983  		for (; num_rsp; num_rsp--, info++) {
af58925c Marcel Holtmann 2014-07-01  3984  			u32 flags;
af58925c Marcel Holtmann 2014-07-01  3985  
00305742 Tomas Bortoli   2019-02-28 @3986  			if ((void *)(info + sizeof(info)) >
                                                                             ^^^^^^^^^^^^^^^^^^^
This is a pointer math bug.  The options to fix it are:

		if ((void *)info + sizeof(info) >

Or:
		if ((void *)(info + 1) >

00305742 Tomas Bortoli   2019-02-28  3987  			   (void *)(skb->data + skb->len))
00305742 Tomas Bortoli   2019-02-28  3988  				break;
00305742 Tomas Bortoli   2019-02-28  3989  
a9de9248 Marcel Holtmann 2007-10-20  3990  			bacpy(&data.bdaddr, &info->bdaddr);
a9de9248 Marcel Holtmann 2007-10-20  3991  			data.pscan_rep_mode	= info->pscan_rep_mode;
a9de9248 Marcel Holtmann 2007-10-20  3992  			data.pscan_period_mode	= info->pscan_period_mode;
a9de9248 Marcel Holtmann 2007-10-20  3993  			data.pscan_mode		= info->pscan_mode;
a9de9248 Marcel Holtmann 2007-10-20  3994  			memcpy(data.dev_class, info->dev_class, 3);
a9de9248 Marcel Holtmann 2007-10-20  3995  			data.clock_offset	= info->clock_offset;
a9de9248 Marcel Holtmann 2007-10-20  3996  			data.rssi		= info->rssi;
41a96212 Marcel Holtmann 2008-07-14  3997  			data.ssp_mode		= 0x00;
3175405b Johan Hedberg   2012-01-04  3998  

regards,
dan carpenter

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