Return-Path: From: Szymon Janc To: linux-bluetooth@vger.kernel.org Cc: Lukasz Rymanowski Subject: [PATCH v2 2/5] shared/gatt-helpers: Improve robustness of get characteristics Date: Thu, 19 Mar 2015 10:56:28 +0100 Message-Id: <1426758991-20055-3-git-send-email-szymon.janc@tieto.com> In-Reply-To: <1426758991-20055-1-git-send-email-szymon.janc@tieto.com> References: <1426758991-20055-1-git-send-email-szymon.janc@tieto.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: From: Lukasz Rymanowski This patch makes sure that we do get into infinite loop when doing search for characteristics It could happen if we got bogus read by type response --- src/shared/gatt-helpers.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/src/shared/gatt-helpers.c b/src/shared/gatt-helpers.c index bbe1de9..4e4c7eb 100644 --- a/src/shared/gatt-helpers.c +++ b/src/shared/gatt-helpers.c @@ -1235,10 +1235,22 @@ static void discover_chrcs_cb(uint8_t opcode, const void *pdu, goto done; } last_handle = get_le16(pdu + length - data_length); + + /* + * If last handle is lower from previous start handle then it is smth + * wrong. Let's stop search, otherwise we might enter infinite loop. + */ + if (last_handle < op->start_handle) { + success = false; + goto done; + } + + op->start_handle = last_handle + 1; + if (last_handle != op->end_handle) { uint8_t pdu[6]; - put_le16(last_handle + 1, pdu); + put_le16(op->start_handle, pdu); put_le16(op->end_handle, pdu + 2); put_le16(GATT_CHARAC_UUID, pdu + 4); @@ -1281,6 +1293,7 @@ struct bt_gatt_request *bt_gatt_discover_characteristics(struct bt_att *att, op->callback = callback; op->user_data = user_data; op->destroy = destroy; + op->start_handle = start; op->end_handle = end; put_le16(start, pdu); -- 1.9.3