* [Linux-kernel-mentees] [PATCH net] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt()
@ 2020-08-05 18:09 Peilin Ye
2020-09-09 7:17 ` [Linux-kernel-mentees] [PATCH net v2] " Peilin Ye
0 siblings, 1 reply; 4+ messages in thread
From: Peilin Ye @ 2020-08-05 18:09 UTC (permalink / raw)
To: Marcel Holtmann, Johan Hedberg
Cc: Peilin Ye, David S. Miller, Jakub Kicinski, Greg Kroah-Hartman,
linux-bluetooth, netdev, linux-kernel-mentees, linux-kernel
`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.
Reported-and-tested-by: syzbot+24ebd650e20bd263ca01@syzkaller.appspotmail.com
Fixes: 2f010b55884e ("Bluetooth: Add support for handling LE Direct Advertising Report events")
Link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
I moved the initialization of `ev` out of the loop and restructured the
function a bit, since otherwise the check would look like:
if (!num_reports || skb->len < num_reports * sizeof(struct hci_ev_le_direct_adv_info) + 1)
return;
Therefore I used the similar structure with hci_inquiry_result_evt() etc.
hci_le_adv_report_evt() and hci_le_ext_adv_report_evt() also have the
same issue with `num_reports`, but I'm not sure how to perform the check
for them, since they use variable-length reports. Should we do something
like this? (take hci_le_adv_report_evt() as example:)
if (!num_reports ||
skb->len < num_reports * (sizeof(*ev) + HCI_MAX_AD_LENGTH + 1) + 1)
return;
Then how about hci_le_ext_adv_report_evt()? There is no such
`HCI_MAX_AD_LENGTH` restrictions on `ev->length` for it, I assume?
Would like to hear your opinion. Thank you!
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);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Linux-kernel-mentees] [PATCH net v2] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt()
2020-08-05 18:09 [Linux-kernel-mentees] [PATCH net] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt() Peilin Ye
@ 2020-09-09 7:17 ` Peilin Ye
2020-11-09 12:16 ` Marcel Holtmann
0 siblings, 1 reply; 4+ messages in thread
From: Peilin Ye @ 2020-09-09 7:17 UTC (permalink / raw)
To: Marcel Holtmann, Johan Hedberg
Cc: Peilin Ye, David S. Miller, Jakub Kicinski, Greg Kroah-Hartman,
linux-bluetooth, netdev, linux-kernel-mentees, linux-kernel
`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);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH net v2] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt()
2020-09-09 7:17 ` [Linux-kernel-mentees] [PATCH net v2] " Peilin Ye
@ 2020-11-09 12:16 ` Marcel Holtmann
2020-11-11 5:18 ` Peilin Ye
0 siblings, 1 reply; 4+ messages in thread
From: Marcel Holtmann @ 2020-11-09 12:16 UTC (permalink / raw)
To: Peilin Ye
Cc: Johan Hedberg, David S. Miller, Jakub Kicinski,
Greg Kroah-Hartman, Bluez mailing list,
open list:NETWORKING [GENERAL],
linux-kernel-mentees, linux-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH net v2] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt()
2020-11-09 12:16 ` Marcel Holtmann
@ 2020-11-11 5:18 ` Peilin Ye
0 siblings, 0 replies; 4+ messages in thread
From: Peilin Ye @ 2020-11-11 5:18 UTC (permalink / raw)
To: Marcel Holtmann
Cc: Johan Hedberg, David S. Miller, Jakub Kicinski,
Greg Kroah-Hartman, Bluez mailing list,
open list:NETWORKING [GENERAL],
linux-kernel-mentees, linux-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-08-05 18:09 [Linux-kernel-mentees] [PATCH net] Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt() Peilin Ye
2020-09-09 7:17 ` [Linux-kernel-mentees] [PATCH net v2] " Peilin Ye
2020-11-09 12:16 ` Marcel Holtmann
2020-11-11 5:18 ` Peilin Ye
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