Return-Path: From: Szymon Janc To: linux-bluetooth@vger.kernel.org Cc: Szymon Janc Subject: [PATCH] shared/gatt-server: Fix crash on read multiple Date: Tue, 13 Mar 2018 08:47:27 +0100 Message-Id: <20180313074727.4600-1-szymon.janc@codecoup.pl> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: When read multiple includes external characteristic, call to gatt_db_attribute_read's complete callback is asynchronous. Fix following crash: Use of uninitialised value of size 8 at 0x49718A: read_multiple_complete_cb (gatt-server.c:994) by 0x498999: pending_read_result (gatt-db.c:136) by 0x49A84B: gatt_db_attribute_read_result (gatt-db.c:1787) by 0x451F4C: read_reply_cb (gatt-database.c:1712) by 0x48B221: method_call_reply (client.c:972) by 0x53AB601: ??? (in /usr/lib64/libdbus-1.so.3.19.3) by 0x53AEF7E: dbus_connection_dispatch (in /usr/lib64/libdbus-1.so.3.19.3) by 0x486FEF: message_dispatch (mainloop.c:72) by 0x50CB576: ??? (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CEB76: g_main_context_dispatch (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CEF1F: ??? (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CF231: g_main_loop_run (in /usr/lib64/libglib-2.0.so.0.5400.3) Invalid read of size 8 at 0x49718A: read_multiple_complete_cb (gatt-server.c:994) by 0x498999: pending_read_result (gatt-db.c:136) by 0x49A84B: gatt_db_attribute_read_result (gatt-db.c:1787) by 0x451F4C: read_reply_cb (gatt-database.c:1712) by 0x48B221: method_call_reply (client.c:972) by 0x53AB601: ??? (in /usr/lib64/libdbus-1.so.3.19.3) by 0x53AEF7E: dbus_connection_dispatch (in /usr/lib64/libdbus-1.so.3.19.3) by 0x486FEF: message_dispatch (mainloop.c:72) by 0x50CB576: ??? (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CEB76: g_main_context_dispatch (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CEF1F: ??? (in /usr/lib64/libglib-2.0.so.0.5400.3) by 0x50CF231: g_main_loop_run (in /usr/lib64/libglib-2.0.so.0.5400.3) Address 0x8 is not stack'd, malloc'd or (recently) free'd --- src/shared/gatt-server.c | 44 ++++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c index a986c5295..faa56abeb 100644 --- a/src/shared/gatt-server.c +++ b/src/shared/gatt-server.c @@ -965,10 +965,8 @@ struct read_multiple_resp_data { static void read_multiple_resp_data_free(struct read_multiple_resp_data *data) { free(data->handles); - data->handles = NULL; - free(data->rsp_data); - data->rsp_data = NULL; + free(data); } static void read_multiple_complete_cb(struct gatt_db_attribute *attr, int err, @@ -1045,38 +1043,38 @@ static void read_multiple_cb(uint8_t opcode, const void *pdu, { struct bt_gatt_server *server = user_data; struct gatt_db_attribute *attr; - struct read_multiple_resp_data data; + struct read_multiple_resp_data *data = NULL; uint8_t ecode = BT_ATT_ERROR_UNLIKELY; size_t i = 0; - data.handles = NULL; - data.rsp_data = NULL; - if (length < 4) { ecode = BT_ATT_ERROR_INVALID_PDU; goto error; } - data.server = server; - data.num_handles = length / 2; - data.cur_handle = 0; - data.mtu = bt_att_get_mtu(server->att); - data.length = 0; - data.rsp_data = malloc(data.mtu - 1); - - if (!data.rsp_data) + data = new0(struct read_multiple_resp_data, 1); + data->handles = NULL; + data->rsp_data = NULL; + data->server = server; + data->num_handles = length / 2; + data->cur_handle = 0; + data->mtu = bt_att_get_mtu(server->att); + data->length = 0; + data->rsp_data = malloc(data->mtu - 1); + + if (!data->rsp_data) goto error; - data.handles = new0(uint16_t, data.num_handles); + data->handles = new0(uint16_t, data->num_handles); - for (i = 0; i < data.num_handles; i++) - data.handles[i] = get_le16(pdu + i * 2); + for (i = 0; i < data->num_handles; i++) + data->handles[i] = get_le16(pdu + i * 2); util_debug(server->debug_callback, server->debug_data, "Read Multiple Req - %zu handles, 1st: 0x%04x", - data.num_handles, data.handles[0]); + data->num_handles, data->handles[0]); - attr = gatt_db_get_attribute(server->db, data.handles[0]); + attr = gatt_db_get_attribute(server->db, data->handles[0]); if (!attr) { ecode = BT_ATT_ERROR_INVALID_HANDLE; @@ -1084,11 +1082,13 @@ static void read_multiple_cb(uint8_t opcode, const void *pdu, } if (gatt_db_attribute_read(attr, 0, opcode, server->att, - read_multiple_complete_cb, &data)) + read_multiple_complete_cb, data)) return; error: - read_multiple_resp_data_free(&data); + if (data) + read_multiple_resp_data_free(data); + bt_att_send_error_rsp(server->att, opcode, 0, ecode); } -- 2.14.3