| Message ID | 20200909071700.1100748-1-yepeilin.cs@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [Linux-kernel-mentees,net,v2] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt() | expand |
Hi Peilin, > `num_reports` is not being properly checked. A malformed event packet with > a large `num_reports` number makes hci_le_direct_adv_report_evt() read out > of bounds. Fix it. > > Cc: stable@vger.kernel.org > Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events") > Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01 > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> > --- > Change in v2: > - add "Cc: stable@" tag. > > net/bluetooth/hci_event.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > index 4b7fc430793c..aec43ae488d1 100644 > --- a/net/bluetooth/hci_event.c > +++ b/net/bluetooth/hci_event.c > @@ -5863,21 +5863,19 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev, > struct sk_buff *skb) > { > u8 num_reports = skb->data[0]; > - void *ptr = &skb->data[1]; > + struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1]; > > - hci_dev_lock(hdev); > + if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1) > + return; > > - while (num_reports--) { > - struct hci_ev_le_direct_adv_info *ev = ptr; > + hci_dev_lock(hdev); > > + for (; num_reports; num_reports--, ev++) > process_adv_report(hdev, ev->evt_type, &ev->bdaddr, > ev->bdaddr_type, &ev->direct_addr, > ev->direct_addr_type, ev->rssi, NULL, 0, > false); > > - ptr += sizeof(*ev); > - } > - > hci_dev_unlock(hdev); > } patch has been applied to bluetooth-next tree. Regards Marcel
On Mon, Nov 09, 2020 at 01:16:53PM +0100, Marcel Holtmann wrote: > Hi Peilin, > > > `num_reports` is not being properly checked. A malformed event packet with > > a large `num_reports` number makes hci_le_direct_adv_report_evt() read out > > of bounds. Fix it. > > > > Cc: stable@vger.kernel.org > > Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events") > > Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com > > Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01 > > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> > > --- > > Change in v2: > > - add "Cc: stable@" tag. > > > > net/bluetooth/hci_event.c | 12 +++++------- > > 1 file changed, 5 insertions(+), 7 deletions(-) > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..aec43ae488d1 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -5863,21 +5863,19 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev, > > struct sk_buff *skb) > > { > > u8 num_reports = skb->data[0]; > > - void *ptr = &skb->data[1]; > > + struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1]; > > > > - hci_dev_lock(hdev); > > + if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1) > > + return; > > > > - while (num_reports--) { > > - struct hci_ev_le_direct_adv_info *ev = ptr; > > + hci_dev_lock(hdev); > > > > + for (; num_reports; num_reports--, ev++) > > process_adv_report(hdev, ev->evt_type, &ev->bdaddr, > > ev->bdaddr_type, &ev->direct_addr, > > ev->direct_addr_type, ev->rssi, NULL, 0, > > false); > > > > - ptr += sizeof(*ev); > > - } > > - > > hci_dev_unlock(hdev); > > } > > patch has been applied to bluetooth-next tree. Thank you for reviewing it, Peilin Ye
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 4b7fc430793c..aec43ae488d1 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5863,21 +5863,19 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) { u8 num_reports = skb->data[0]; - void *ptr = &skb->data[1]; + struct hci_ev_le_direct_adv_info *ev = (void *)&skb->data[1]; - hci_dev_lock(hdev); + if (!num_reports || skb->len < num_reports * sizeof(*ev) + 1) + return; - while (num_reports--) { - struct hci_ev_le_direct_adv_info *ev = ptr; + hci_dev_lock(hdev); + for (; num_reports; num_reports--, ev++) process_adv_report(hdev, ev->evt_type, &ev->bdaddr, ev->bdaddr_type, &ev->direct_addr, ev->direct_addr_type, ev->rssi, NULL, 0, false); - ptr += sizeof(*ev); - } - hci_dev_unlock(hdev); }
`num_reports` is not being properly checked. A malformed event packet with a large `num_reports` number makes hci_le_direct_adv_report_evt() read out of bounds. Fix it. Cc: stable@vger.kernel.org Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events") Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01 Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> --- Change in v2: - add "Cc: stable@" tag. net/bluetooth/hci_event.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)