[PATCH v2 3/5] shared/gatt-helpers: Improve robustness of get include services

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From: Lukasz Rymanowski <lukasz.rymanowski@xxxxxxxxx>

This patch makes sure that we do get into infinite loop when doing
search for included services.

It could happen if we got bogus read by type response
---
 src/shared/gatt-helpers.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/shared/gatt-helpers.c b/src/shared/gatt-helpers.c
index 4e4c7eb..78aca7d 100644
--- a/src/shared/gatt-helpers.c
+++ b/src/shared/gatt-helpers.c
@@ -1125,10 +1125,21 @@ static void discover_included_cb(uint8_t opcode, const void *pdu,
 	}
 
 	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 failed;
+	}
+
+	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_INCLUDE_UUID, pdu + 4);
 
@@ -1171,6 +1182,7 @@ struct bt_gatt_request *bt_gatt_discover_included_services(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

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