RE: [PATCH v1] Bluetooth: btintel: Fix bdaddress comparison with garbage value

Hi Marcel,

-----Original Message-----
From: Marcel Holtmann <marcel@holtmann.org>
Sent: Tuesday, October 12, 2021 9:27 PM
To: K, Kiran <redacted>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>; linux-bluetooth <linux-
bluetooth@vger.kernel.org>; Srivatsa, Ravishankar
[off-list ref]; Tumkur Narayan, Chethan
[off-list ref]; An, Tedd [off-list ref]
Subject: Re: [PATCH v1] Bluetooth: btintel: Fix bdaddress comparison with
garbage value

Hi Kiran,

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Intel Read Verision(TLV) data is parsed into a local structure
variable and it contains a field for bd address. Bd address is
returned only in bootloader mode and hence bd address in TLV
structure needs to be validated only if controller is present in
boot loader

mode.

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Signed-off-by: Kiran K <redacted>
---
drivers/bluetooth/btintel.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/bluetooth/btintel.c

b/drivers/bluetooth/btintel.c index 9359bff47296..d1703cc99705
100644

--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c

@@ -2081,14 +2081,16 @@ static int

btintel_prepare_fw_download_tlv(struct hci_dev *hdev,

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     if (ver->img_type == 0x03) {
             btintel_clear_flag(hdev, INTEL_BOOTLOADER);
             btintel_check_bdaddr(hdev);
-     }
-
-     /* If the OTP has no valid Bluetooth device address, then there will
-      * also be no valid address for the operational firmware.
-      */
-     if (!bacmp(&ver->otp_bd_addr, BDADDR_ANY)) {
-             bt_dev_info(hdev, "No device address configured");
-             set_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks);
+     } else {
+             /*
+              * Check for valid bd address in boot loader mode. Device
+              * will be marked as unconfigured if empty bd address is
+              * found.
+              */
+             if (!bacmp(&ver->otp_bd_addr, BDADDR_ANY)) {
+                     bt_dev_info(hdev, "No device address configured");
+                     set_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks);
+             }
     }

     btintel_get_fw_name_tlv(ver, fwname, sizeof(fwname), "sfi");

@@ -2466,6 +2468,7 @@ static int btintel_setup_combined(struct

hci_dev *hdev)

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             goto exit_error;
     }

+     memset(&ver_tlv, 0, sizeof(ver_tlv));

this change is not described in the commit message. Why is that now
out of

a sudden needed?

I guess this is just to make sure the ver_tlv is initialized so its
otp_bd_addr be set to all zeros (BDADDR_ANY) otherwise the code above
doesn't work as it attempts to compare to BDADDR_ANY.

Yes. If not memset, then garbage value is compared against BDADDR_ANY.

since that is not obviously clear, the takeaway from my review should have
been that you either describe this properly in the commit message or you
add a comment.

I will add a comment and send an updated patch. Thanks.

Regards

Marcel