Re: [PATCH v2] Bluetooth: Move force_bredr_smp debugfs into hci_debugfs_create_bredr

From: Luiz Augusto von Dentz
Date: Tue Oct 27 2020 - 13:21:03 EST


On Tue, Oct 27, 2020 at 10:12 AM Alain Michaud <alainmichaud@xxxxxxxxxx> wrote:
>
> Friendly ping and adding my review-by tag.
>
>
> On Wed, Oct 7, 2020 at 12:38 AM Claire Chang <tientzu@xxxxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > This patch is to fix the kernel error
> > [ 46.271811] debugfs: File 'force_bredr_smp' in directory 'hci0'
> > already present!
> >
> > When powering off and on the bluetooth, the smp_register will try to create the
> > force_bredr_smp entry again.
> > Move the creation to hci_debugfs_create_bredr so the force_bredr_smp entry will
> > only be created when HCI_SETUP and HCI_CONFIG are not set.
> >
> > Thanks,
> > Claire
> >
> > On Tue, Sep 29, 2020 at 4:03 PM Claire Chang <tientzu@xxxxxxxxxxxx> wrote:
> > >
> > > Avoid multiple attempts to create the debugfs entry, force_bredr_smp,
> > > by moving it from the SMP registration to the BR/EDR controller init
> > > section. hci_debugfs_create_bredr is only called when HCI_SETUP and
> > > HCI_CONFIG is not set.
> > >
> > > Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
> Reviewed-by: Alain Michaud <alainm@xxxxxxxxxxxx>

Reviewed-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

> > > ---
> > > v2: correct a typo in commit message
> > >
> > > net/bluetooth/hci_debugfs.c | 50 +++++++++++++++++++++++++++++++++++++
> > > net/bluetooth/smp.c | 44 ++------------------------------
> > > net/bluetooth/smp.h | 2 ++
> > > 3 files changed, 54 insertions(+), 42 deletions(-)
> > >
> > > diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
> > > index 5e8af2658e44..4626e0289a97 100644
> > > --- a/net/bluetooth/hci_debugfs.c
> > > +++ b/net/bluetooth/hci_debugfs.c
> > > @@ -494,6 +494,45 @@ static int auto_accept_delay_get(void *data, u64 *val)
> > > DEFINE_SIMPLE_ATTRIBUTE(auto_accept_delay_fops, auto_accept_delay_get,
> > > auto_accept_delay_set, "%llu\n");
> > >
> > > +static ssize_t force_bredr_smp_read(struct file *file,
> > > + char __user *user_buf,
> > > + size_t count, loff_t *ppos)
> > > +{
> > > + struct hci_dev *hdev = file->private_data;
> > > + char buf[3];
> > > +
> > > + buf[0] = hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP) ? 'Y' : 'N';
> > > + buf[1] = '\n';
> > > + buf[2] = '\0';
> > > + return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
> > > +}
> > > +
> > > +static ssize_t force_bredr_smp_write(struct file *file,
> > > + const char __user *user_buf,
> > > + size_t count, loff_t *ppos)
> > > +{
> > > + struct hci_dev *hdev = file->private_data;
> > > + bool enable;
> > > + int err;
> > > +
> > > + err = kstrtobool_from_user(user_buf, count, &enable);
> > > + if (err)
> > > + return err;
> > > +
> > > + err = smp_force_bredr(hdev, enable);
> > > + if (err)
> > > + return err;
> > > +
> > > + return count;
> > > +}
> > > +
> > > +static const struct file_operations force_bredr_smp_fops = {
> > > + .open = simple_open,
> > > + .read = force_bredr_smp_read,
> > > + .write = force_bredr_smp_write,
> > > + .llseek = default_llseek,
> > > +};
> > > +
> > > static int idle_timeout_set(void *data, u64 val)
> > > {
> > > struct hci_dev *hdev = data;
> > > @@ -589,6 +628,17 @@ void hci_debugfs_create_bredr(struct hci_dev *hdev)
> > > debugfs_create_file("voice_setting", 0444, hdev->debugfs, hdev,
> > > &voice_setting_fops);
> > >
> > > + /* If the controller does not support BR/EDR Secure Connections
> > > + * feature, then the BR/EDR SMP channel shall not be present.
> > > + *
> > > + * To test this with Bluetooth 4.0 controllers, create a debugfs
> > > + * switch that allows forcing BR/EDR SMP support and accepting
> > > + * cross-transport pairing on non-AES encrypted connections.
> > > + */
> > > + if (!lmp_sc_capable(hdev))
> > > + debugfs_create_file("force_bredr_smp", 0644, hdev->debugfs,
> > > + hdev, &force_bredr_smp_fops);
> > > +
> > > if (lmp_ssp_capable(hdev)) {
> > > debugfs_create_file("ssp_debug_mode", 0444, hdev->debugfs,
> > > hdev, &ssp_debug_mode_fops);
> > > diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
> > > index 433227f96c73..8b817e4358fd 100644
> > > --- a/net/bluetooth/smp.c
> > > +++ b/net/bluetooth/smp.c
> > > @@ -3353,31 +3353,8 @@ static void smp_del_chan(struct l2cap_chan *chan)
> > > l2cap_chan_put(chan);
> > > }
> > >
> > > -static ssize_t force_bredr_smp_read(struct file *file,
> > > - char __user *user_buf,
> > > - size_t count, loff_t *ppos)
> > > +int smp_force_bredr(struct hci_dev *hdev, bool enable)
> > > {
> > > - struct hci_dev *hdev = file->private_data;
> > > - char buf[3];
> > > -
> > > - buf[0] = hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP) ? 'Y': 'N';
> > > - buf[1] = '\n';
> > > - buf[2] = '\0';
> > > - return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
> > > -}
> > > -
> > > -static ssize_t force_bredr_smp_write(struct file *file,
> > > - const char __user *user_buf,
> > > - size_t count, loff_t *ppos)
> > > -{
> > > - struct hci_dev *hdev = file->private_data;
> > > - bool enable;
> > > - int err;
> > > -
> > > - err = kstrtobool_from_user(user_buf, count, &enable);
> > > - if (err)
> > > - return err;
> > > -
> > > if (enable == hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP))
> > > return -EALREADY;
> > >
> > > @@ -3399,16 +3376,9 @@ static ssize_t force_bredr_smp_write(struct file *file,
> > >
> > > hci_dev_change_flag(hdev, HCI_FORCE_BREDR_SMP);
> > >
> > > - return count;
> > > + return 0;
> > > }
> > >
> > > -static const struct file_operations force_bredr_smp_fops = {
> > > - .open = simple_open,
> > > - .read = force_bredr_smp_read,
> > > - .write = force_bredr_smp_write,
> > > - .llseek = default_llseek,
> > > -};
> > > -
> > > int smp_register(struct hci_dev *hdev)
> > > {
> > > struct l2cap_chan *chan;
> > > @@ -3433,17 +3403,7 @@ int smp_register(struct hci_dev *hdev)
> > >
> > > hdev->smp_data = chan;
> > >
> > > - /* If the controller does not support BR/EDR Secure Connections
> > > - * feature, then the BR/EDR SMP channel shall not be present.
> > > - *
> > > - * To test this with Bluetooth 4.0 controllers, create a debugfs
> > > - * switch that allows forcing BR/EDR SMP support and accepting
> > > - * cross-transport pairing on non-AES encrypted connections.
> > > - */
> > > if (!lmp_sc_capable(hdev)) {
> > > - debugfs_create_file("force_bredr_smp", 0644, hdev->debugfs,
> > > - hdev, &force_bredr_smp_fops);
> > > -
> > > /* Flag can be already set here (due to power toggle) */
> > > if (!hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP))
> > > return 0;
> > > diff --git a/net/bluetooth/smp.h b/net/bluetooth/smp.h
> > > index 121edadd5f8d..fc35a8bf358e 100644
> > > --- a/net/bluetooth/smp.h
> > > +++ b/net/bluetooth/smp.h
> > > @@ -193,6 +193,8 @@ bool smp_irk_matches(struct hci_dev *hdev, const u8 irk[16],
> > > int smp_generate_rpa(struct hci_dev *hdev, const u8 irk[16], bdaddr_t *rpa);
> > > int smp_generate_oob(struct hci_dev *hdev, u8 hash[16], u8 rand[16]);
> > >
> > > +int smp_force_bredr(struct hci_dev *hdev, bool enable);
> > > +
> > > int smp_register(struct hci_dev *hdev);
> > > void smp_unregister(struct hci_dev *hdev);
> > >
> > > --
> > > 2.28.0.618.gf4bc123cb7-goog
> > >



--
Luiz Augusto von Dentz