shared/gatt-db: fix crash on bad attribute index In gatt_db_attribute_get_value(), avoid NULL pointer deref if attribute or db is in unexpected state and attrib at index-1 is missing. Fixes btmon -r crash, on a packet capture obtained with btmon -w after clearing BlueZ attributes & cache for the device: ==208213==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000000c ==208213==The signal is caused by a READ memory access. ==208213==Hint: address points to the zero page. #0 0x5af4a6 in bt_uuid_to_uuid128 lib/uuid.c:65 #1 0x5afd54 in bt_uuid_cmp lib/uuid.c:118 #2 0x5d0dd2 in gatt_db_attribute_get_value src/shared/gatt-db.c:1663 #3 0x56aeab in print_value monitor/att.c:158 #4 0x56b80f in print_attribute monitor/att.c:207 #5 0x5982f7 in print_handle monitor/att.c:4417 #6 0x59b1b8 in print_write monitor/att.c:4598 #7 0x59b796 in att_write_req monitor/att.c:4627 #8 0x59e91e in att_packet monitor/att.c:4918 #9 0x4f4847 in l2cap_frame monitor/l2cap.c:2567 #10 0x4f6022 in l2cap_packet monitor/l2cap.c:2708 #11 0x4a48f6 in packet_hci_acldata monitor/packet.c:12606 #12 0x43952a in packet_monitor monitor/packet.c:4247 #13 0x4170c9 in control_reader monitor/control.c:1517 #14 0x402f76 in main monitor/main.c:277

Diffstat

1 files changed, 2 insertions(+), 0 deletions(-)