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From:   Ildar Kamaletdinov <i.kamaletdinov@omp.ru>
To:     <linux-bluetooth@vger.kernel.org>
CC:     Ildar Kamaletdinov <i.kamaletdinov@omp.ru>
Subject: [PATCH BlueZ 6/6] gatt: Fix double free and freed memory dereference
Date:   Fri, 1 Apr 2022 15:16:47 +0300
Message-ID: <20220401121647.3985682-7-i.kamaletdinov@omp.ru>
In-Reply-To: <20220401121647.3985682-1-i.kamaletdinov@omp.ru>
References: <20220401121647.3985682-1-i.kamaletdinov@omp.ru>
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If device is no longer exists or not paired when notifications send it
is possible to get double free and dereference of already freed memory.

To avoid this we need to recheck the state of device after sending
notification.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.
---
 src/gatt-database.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/gatt-database.c b/src/gatt-database.c
index d6c94058c..d32f616a9 100644
--- a/src/gatt-database.c
+++ b/src/gatt-database.c
@@ -3877,6 +3877,10 @@ void btd_gatt_database_server_connected(struct btd_gatt_database *database,
 
 	send_notification_to_device(state, state->pending);
 
+	state = find_device_state(database, &bdaddr, bdaddr_type);
+	if (!state || !state->pending)
+		return;
+
 	free(state->pending->value);
 	free(state->pending);
 	state->pending = NULL;
-- 
2.35.1