shared/gatt: Fix gatt-db buffer overflow for cloned db

On notify_service_changed() timeout, db_hash_update() is called but for cloned db the last-handle has not been copied and only one slot is allocated, ending in buffer overflow:

==288975==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x5020000ac220 at pc 0x55f8b7e551bf bp 0x7ffcd6e9ddf0 sp 0x7ffcd6e9dde0 WRITE of size 8 at 0x5020000ac220 thread T0

    #0 0x55f8b7e551be in gen_hash_m src/shared/gatt-db.c:415
    #1 0x55f8b7e5d817 in gatt_db_service_foreach src/shared/gatt-db.c:1744
    #2 0x55f8b7e5d817 in gatt_db_service_foreach src/shared/gatt-db.c:1722
    #3 0x55f8b7e60c6c in foreach_service_in_range src/shared/gatt-db.c:1633
    #4 0x55f8b7e60c6c in foreach_in_range src/shared/gatt-db.c:1656
    #5 0x55f8b7dde002 in queue_foreach src/shared/queue.c:207
    #6 0x55f8b7e5c435 in gatt_db_foreach_service_in_range src/shared/gatt-db.c:1698
    #7 0x55f8b7e5c87c in db_hash_update src/shared/gatt-db.c:442
    #8 0x55f8b7f15283 in timeout_callback src/shared/timeout-glib.c:25
    #9 0x7fc1845154f1  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5e4f1) (BuildId: 116e142b9b52c8a4dfd403e759e71ab8f95d8bb3)
    #10 0x7fc18451445d  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5d45d) (BuildId: 116e142b9b52c8a4dfd403e759e71ab8f95d8bb3)
    #11 0x7fc184573976  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0xbc976) (BuildId: 116e142b9b52c8a4dfd403e759e71ab8f95d8bb3)
    #12 0x7fc184514f46 in g_main_loop_run (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5df46) (BuildId: 116e142b9b52c8a4dfd403e759e71ab8f95d8bb3)
    #13 0x55f8b7f157e8 in mainloop_run src/shared/mainloop-glib.c:65
    #14 0x55f8b7f16116 in mainloop_run_with_signal src/shared/mainloop-notify.c:196
    #15 0x55f8b7af46df in main src/main.c:1709
    #16 0x7fc18382a1c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #17 0x7fc18382a28a in __libc_start_main_impl ../csu/libc-start.c:360
    #18 0x55f8b7af68b4 in _start (/home/fdanis/src/bluez/src/bluetoothd+0x6588b4) (BuildId: 89dc89ac5800f58cc305bae57a965b1185601a3e)

0x5020000ac220 is located 0 bytes after 16-byte region [0x5020000ac210,0x5020000ac220) allocated by thread T0 here:

    #0 0x7fc1846fd9c7 in malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
    #1 0x55f8b7ddf2b6 in util_malloc src/shared/util.c:46
---
 src/shared/gatt-db.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 87cc61cf3..751d4c3da 100644
@@ -330,6 +330,7 @@ struct gatt_db *gatt_db_clone(struct gatt_db *db)
 		return NULL;
 
 	queue_foreach(db->services, service_clone, clone);
+	clone->last_handle = db->last_handle;
 
 	return clone;
 }

@@ -433,7 +434,7 @@ static bool db_hash_update(void *user_data)
 
 	db->hash_id = 0;
 
-	if (gatt_db_isempty(db))
+	if (gatt_db_isempty(db) || !db->last_handle)
 		return false;
 
 	hash.iov = new0(struct iovec, db->last_handle + 1);

2.43.0