Hi,
On 10/4/20 7:17 AM, Anant Thazhemadam wrote:
When h5_close() is called and !hu->serdev, h5 is directly freed.
However, h5->rx_skb is not freed before h5 is freed, which causes
a memory leak.
Freeing h5->rx_skb (when !hu->serdev) fixes this memory leak before
freeing h5.
Fixes: ce945552fde4 ("Bluetooth: hci_h5: Add support for serdev enumerated devices")
Reported-by: syzbot+6ce141c55b2f7aafd1c4@xxxxxxxxxxxxxxxxxxxxxxxxx
Tested-by: syzbot+6ce141c55b2f7aafd1c4@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@xxxxxxxxx>
---
Changes in v3:
* Free h5->rx_skb when !hu->serdev, and fix the memory leak
* Do not incorrectly and unnecessarily call serdev_device_close()
Changes in v2:
* Fixed the Fixes tag
Hans de Goede also suggested calling h5_reset_rx() on close (for both, !hu->serdev
and hu->serdev cases).
However, doing so seems to lead to a null-ptr-dereference error,
https://syzkaller.appspot.com/text?tag=CrashReport&x=136a9a5d900000,
and for this reason, it has not been implemented.
Instead, directly freeing h5->rx_skb seems to suffice in preventing the memory leak
reported.
And since h5 is freed immediately after freeing h5->rx_skb, assigning h5->rx_skb to
be NULL isn't necessary.
drivers/bluetooth/hci_h5.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index e41854e0d79a..171e55c080ce 100644
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -248,8 +248,10 @@ static int h5_close(struct hci_uart *hu)
if (h5->vnd && h5->vnd->close)
h5->vnd->close(h5);
- if (!hu->serdev)
+ if (!hu->serdev){
+ kfree_skb(h5->rx_skb);
kfree(h5);
+ }
return 0;
}
To fully fix the memleak you also need to add a kfree_skb(h5->rx_skb);
call to the end of h5_serdev_remove(), because in the hu->serdev case
that is where the h5 struct will be free-ed (it is free-ed after that
function exits).
Regards,
Hans
