Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Alain Michaud <alainm@chromium.org>
To:     linux-bluetooth@vger.kernel.org
Cc:     Alain Michaud <alainm@chromium.org>
Subject: [BlueZ PATCH v2] shared/gatt-client:Ignore orphaned characteristics
Date:   Fri,  1 May 2020 19:22:17 +0000
Message-Id: <20200501192218.73993-1-alainm@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

The gatt discovery proceedure simplification to discover all
characteristics at once has exposed a device side issue where some
device implementation reports orphaned characteristics.  While this
technically shouldn't be allowed, some instances of this were observed
(namely on some Android phones).

The fix is to simply skip over orphaned characteristics and continue
with everything else that is valid.

This has been tested as part of the Android CTS tests against an
affected platform and was confirmed to have worked around the issue.

Signed-off-by: Alain Michaud <alainm@chromium.org>
---

 src/shared/gatt-client.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index 963ad619f..507b4d304 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -632,7 +632,13 @@ static bool discover_descs(struct discovery_op *op, bool *discovering)
 			util_debug(client->debug_callback, client->debug_data,
 				"Failed to insert characteristic at 0x%04x",
 				chrc_data->value_handle);
-			goto failed;
+
+			/* Some devices have been seen reporting orphaned
+			 * characteristics.  In order to favor interoperability
+			 * we skip over characteristics in error
+			 */
+			free(chrc_data);
+			continue;
 		}
 
 		if (gatt_db_attribute_get_handle(attr) !=
-- 
2.26.2.526.g744177e7f7-goog