[BlueZ,v1,0/1] shared/gatt-db: Fix incorrect attribute type

Message

Sarveshwar Bajaj Feb. 21, 2025, 4:31 p.m. UTC

As part of BLE GATT Fuzzing testcase,if application sends an invalid
ATT_FIND_BY_TYPE_VALUE_REQ with attribute type as CCC (UUID 0x2902).
However, this request is not valid for descriptors like CCC, as it is 
specifically intended for discovering primary services with a given UUID.
When processed in find_by_type(),attempts to access attribute->value 
without checking if attribute or attribute->value is NULL,leading to a 
segmentation fault.

Added NULL pointer checks before accessing attribute values in multiple
functions to prevent potential crashes due to invalid memory access

Bluetoothd crash dump:
0 0x73fec87ae81e  (/lib/x86_64-linux-gnu/libc.so.6+0x1ae81e)
1 0x73fec94942e9 in MemcmpInterceptorCommon(void*, int (*)
(void const*, void const*, unsigned long), void const*, 
void const*, unsigned long) 
../../../../src/libsanitizer/sanitizer_common/
sanitizer_common_interceptors.inc:881
2 0x73fec9494bc6 in __interceptor_memcmp ../../../../src/
libsanitizer/sanitizer_common
/sanitizer_common_interceptors.inc:892
3 0x73fec9494bc6 in __interceptor_memcmp ../../../../src/
libsanitizer/sanitizer_common
/sanitizer_common_interceptors.inc:887
4 0x5d5c290f2456 in find_by_type src/shared/gatt-db.c:1389
5 0x5d5c290ff855 in foreach_in_range src/shared/gatt-db.c:1549
6 0x5d5c29099752 in queue_foreach src/shared/queue.c:207
7 0x5d5c290fb085 in gatt_db_foreach_in_range src/shared/gatt-db.c:1593
8 0x5d5c290fb4ca in gatt_db_find_by_type_value src/shared/gatt-db.c:1434
9 0x5d5c290e1996 in find_by_type_val_cb src/shared/gatt-server.c:745
10 0x5d5c290c3083 in handle_notify src/shared/att.c:1015
11 0x5d5c290c3083 in can_read_data src/shared/att.c:1100
12 0x5d5c291867c1 in watch_callback src/shared/io-glib.c:157
13 0x73fec931bc43 in g_main_context_dispatch 
(/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x55c43)
14 0x73fec93712b7  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0xab2b7)
15 0x73fec931b2b2 in g_main_loop_run (/lib/x86_64-linux-gnu/
libglib-2.0.so.0+0x552b2)
16 0x5d5c29188518 in mainloop_run src/shared/mainloop-glib.c:66
17 0x5d5c29188e26 in mainloop_run_with_signal src/shared
/mainloop-notify.c:189
18 0x5d5c28d8c6ae in main src/main.c:1544
19 0x73fec8629d8f in __libc_start_call_main ../sysdeps/nptl/
libc_start_call_main.h:58
20 0x73fec8629e3f in __libc_start_main_impl ../csu/libc-start.c:392
21 0x5d5c28d8f4c4 in _start (/root/LE_Audio_Work/Bluez/bluez/
src/bluetoothd+0x6204c4)

Sarveshwar Bajaj (1):
  shared/gatt-db: Fix incorrect attribute type handling

 src/shared/gatt-db.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)