[Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Linux-kernel-mentees] [PATCH] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Peilin Ye]

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it. Also, make `num_rsp` unsigned.

This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
 net/bluetooth/hci_event.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..29aff5e7dec2 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4369,13 +4369,13 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 					    struct sk_buff *skb)
 {
 	struct inquiry_data data;
-	struct extended_inquiry_info *info = (void *) (skb->data + 1);
-	int num_rsp = *((__u8 *) skb->data);
+	struct extended_inquiry_info *info = (void *)(skb->data + 1);
+	__u8 num_rsp = *((__u8 *)skb->data);
 	size_t eir_len;
 
 	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
 
-	if (!num_rsp)
+	if (!num_rsp || num_rsp * sizeof(*info) > skb->truesize)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
-- 
2.25.1

[Linux-kernel-mentees] [PATCH v2] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Peilin Ye]

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it.

This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Changes in v2:
    - Use `skb->len` instead of `skb->truesize` as the length limit.
    - Leave `num_rsp` as of type `int`.

 net/bluetooth/hci_event.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..91cb3707d20a 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4375,7 +4375,7 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 
 	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
 
-	if (!num_rsp)
+	if (!num_rsp || skb->len < num_rsp * sizeof(*info))
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
-- 
2.25.1

Re: [Linux-kernel-mentees] [PATCH v2] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Greg KH]

On Thu, Jul 09, 2020 at 09:02:24AM -0400, Peilin Ye wrote:
> Check upon `num_rsp` is insufficient. A malformed event packet with a
> large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
> of bounds. Fix it.
> 
> This patch fixes the following syzbot bug:
> 
>     https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2
> 
> Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bluetooth maintainers, can you also add a cc: stable on this so it gets
picked up properly there?

thanks,

greg k-h

[Linux-kernel-mentees] [PATCH v3] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Peilin Ye]

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it.

This patch fixes the following syzbot bug:

    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Change in v3:
    - Minimum `skb->len` requirement was 1 byte inaccurate since `info`
      starts from `skb->data + 1`. Fix it.

Changes in v2:
    - Use `skb->len` instead of `skb->truesize` as the length limit.
    - Leave `num_rsp` as of type `int`.

 net/bluetooth/hci_event.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..13d8802b8137 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4375,7 +4375,7 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,
 
 	BT_DBG("%s num_rsp %d", hdev->name, num_rsp);
 
-	if (!num_rsp)
+	if (!num_rsp || skb->len < num_rsp * sizeof(*info) + 1)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
-- 
2.25.1

Re: [Linux-kernel-mentees] [PATCH v3] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Marcel Holtmann]

Hi Peilin,

> Check upon `num_rsp` is insufficient. A malformed event packet with a
> large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
> of bounds. Fix it.
> 
> This patch fixes the following syzbot bug:
> 
>    https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2
> 
> Reported-by: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
> Cc: stable@vger.kernel.org
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> Change in v3:
>    - Minimum `skb->len` requirement was 1 byte inaccurate since `info`
>      starts from `skb->data + 1`. Fix it.
> 
> Changes in v2:
>    - Use `skb->len` instead of `skb->truesize` as the length limit.
>    - Leave `num_rsp` as of type `int`.
> 
> net/bluetooth/hci_event.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel

Re: maybe similar bug exists for HCI_EV_INQUIRY_RESULT* like [Linux-kernel-mentees] [PATCH v2] net/bluetooth: slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Alexander Larkin]

For the net/bluetooth/hci_event.c , maybe similar bug could be inside
hci_inquiry_result_with_rssi_evt() that is HCI_EV_INQUIRY_RESULT_WITH_RSSI
and inside hci_inquiry_result_evt() that is HCI_EV_INQUIRY_RESULT. 

Re: maybe similar bug exists for HCI_EV_INQUIRY_RESULT* like [Linux-kernel-mentees] [PATCH v2] net/bluetooth: slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Peilin Ye]

On Thu, Jul 01, 2021 at 06:39:36PM +0300, Alexander Larkin wrote:
> For the net/bluetooth/hci_event.c , maybe similar bug could be inside
> hci_inquiry_result_with_rssi_evt() that is HCI_EV_INQUIRY_RESULT_WITH_RSSI
> and inside hci_inquiry_result_evt() that is HCI_EV_INQUIRY_RESULT. 

Hi Alexander,

Thanks for looking into this, I believe they were handled in commit
629b49c848ee ("Bluetooth: Prevent out-of-bounds read in
hci_inquiry_result_with_rssi_evt()") and commit 75bbd2ea50ba ("Bluetooth:
Prevent out-of-bounds read in hci_inquiry_result_evt()").

Thanks,
Peilin Ye