[ This is an old warning. Sorry for missing it earlier. I would have caught it when the code was merged as well so there was no real risk but it's just awkward. ] 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 6039aa73 Gustavo Padovan 2012-05-23 3963 static void hci_inquiry_result_with_rssi_evt(struct hci_dev *hdev, 807deac2 Gustavo Padovan 2012-05-17 3964 struct sk_buff *skb) a9de9248 Marcel Holtmann 2007-10-20 3965 { a9de9248 Marcel Holtmann 2007-10-20 3966 struct inquiry_data data; a9de9248 Marcel Holtmann 2007-10-20 3967 int num_rsp = *((__u8 *) skb->data); a9de9248 Marcel Holtmann 2007-10-20 3968 a9de9248 Marcel Holtmann 2007-10-20 3969 BT_DBG("%s num_rsp %d", hdev->name, num_rsp); a9de9248 Marcel Holtmann 2007-10-20 3970 a9de9248 Marcel Holtmann 2007-10-20 3971 if (!num_rsp) a9de9248 Marcel Holtmann 2007-10-20 3972 return; a9de9248 Marcel Holtmann 2007-10-20 3973 d7a5a11d Marcel Holtmann 2015-03-13 3974 if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ)) 1519cc17 Andre Guedes 2012-03-21 3975 return; 1519cc17 Andre Guedes 2012-03-21 3976 a9de9248 Marcel Holtmann 2007-10-20 3977 hci_dev_lock(hdev); a9de9248 Marcel Holtmann 2007-10-20 3978 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 should be (void *)info + sizeof(info). The code you have will break for valid uses because the pointer math error. I notice that this isn't merged into linux-next, but it does seem required. I am writing a similar fix for a different function. Another way to write this would be: if ((u8 *)(info + 1) > &skb->data[skb->len]) { 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 af58925c Marcel Holtmann 2014-07-01 3999 flags = hci_inquiry_cache_update(hdev, &data, false); af58925c Marcel Holtmann 2014-07-01 4000 48264f06 Johan Hedberg 2011-11-09 4001 mgmt_device_found(hdev, &info->bdaddr, ACL_LINK, 0x00, e17acd40 Johan Hedberg 2011-03-30 4002 info->dev_class, info->rssi, af58925c Marcel Holtmann 2014-07-01 4003 flags, NULL, 0, NULL, 0); a9de9248 Marcel Holtmann 2007-10-20 4004 } a9de9248 Marcel Holtmann 2007-10-20 4005 } else { --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
