On Wed, Sep 09, 2020 at 10:06:59PM -0700, Eric Biggers wrote: > On Thu, Sep 10, 2020 at 10:04:24AM +0530, Anmol Karn wrote: > > Prevent hci_phy_link_complete_evt() from dereferencing 'hcon->amp_mgr' > > as NULL. Fix it by adding pointer check for it. > > > > Reported-and-tested-by: syzbot+0bef568258653cff272f@xxxxxxxxxxxxxxxxxxxxxxxxx > > Link: https://syzkaller.appspot.com/bug?extid=0bef568258653cff272f > > Signed-off-by: Anmol Karn <anmol.karan123@xxxxxxxxx> > > --- > > net/bluetooth/hci_event.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c > > index 4b7fc430793c..871e16804433 100644 > > --- a/net/bluetooth/hci_event.c > > +++ b/net/bluetooth/hci_event.c > > @@ -4936,6 +4936,11 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev, > > return; > > } > > > > + if (IS_ERR_OR_NULL(hcon->amp_mgr)) { > > + hci_dev_unlock(hdev); > > + return; > > + } > > + > Hello Sir, > In patches that fix a NULL pointer dereference, please include a brief > explanation of why the pointer can be NULL, including what it means > semantically; and why the proposed change is the best fix for the problem. > I will surely add more explaination in v2. > Also, why IS_ERR_OR_NULL()? > I used IS_ERR_OR_NULL() to check if the 'hcon->amp_mgr' is a valid pointer or not, and unregister the 'hcon' and signal error, but will make changes in v2 with only NULL check included, if you think it's incorrect to use IS_ERR check here along with NULL. Thanks, Anmol Karn
