shared/gatt-server: Fix crash on read multiple
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
diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c
index a986c52..faa56ab 100644
--- a/src/shared/gatt-server.c
+++ b/src/shared/gatt-server.c
@@ -965,10 +965,8 @@
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 @@
{
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);
+ 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)
+ 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 @@
}
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);
}
