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

From: Dan Carpenter
Date: Mon Mar 04 2019 - 10:04:47 EST


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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