From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Brian Delwiche Date: Tue, 23 May 2023 23:23:11 +0000 Subject: [PATCH] Fix some OOB errors in BTM parsing Some HCI BLE events are missing bounds checks, leading to possible OOB access. Add the appropriate bounds checks on the packets. Bug: 279169188 Test: atest bluetooth_test_gd_unit, net_test_stack_btm Tag: #security Ignore-AOSP-First: Security (cherry picked from https://googleplex-android-review.googlesource.com/q/commit:949eb6b355f1bdcfb5567ebe1b7f00a61b6fb066) Merged-In: Icf2953c687d9c4e2ca9629474151b8deab6c5f57 Change-Id: Icf2953c687d9c4e2ca9629474151b8deab6c5f57 --- stack/btm/btm_ble_gap.cc | 50 ++++++++++++++++++++++++++++++---------- stack/btu/btu_hcif.cc | 6 +++++ 2 files changed, 44 insertions(+), 12 deletions(-) diff --git a/stack/btm/btm_ble_gap.cc b/stack/btm/btm_ble_gap.cc index 4f09f270a..17a87ed95 100644 --- a/stack/btm/btm_ble_gap.cc +++ b/stack/btm/btm_ble_gap.cc @@ -1877,19 +1877,27 @@ void btm_ble_process_ext_adv_pkt(uint8_t data_len, uint8_t* data) { advertising_sid; int8_t rssi, tx_power; uint16_t event_type, periodic_adv_int, direct_address_type; + size_t bytes_to_process; /* Only process the results if the inquiry is still active */ if (!BTM_BLE_IS_SCAN_ACTIVE(btm_cb.ble_ctr_cb.scan_activity)) return; + bytes_to_process = 1; + + if (data_len < bytes_to_process) { + LOG(ERROR) << "Malformed LE extended advertising packet: not enough room " + "for num reports"; + return; + } + /* Extract the number of reports in this event. */ STREAM_TO_UINT8(num_reports, p); while (num_reports--) { - if (p > data + data_len) { - // TODO(jpawlowski): we should crash the stack here - BTM_TRACE_ERROR( - "Malformed LE Extended Advertising Report Event from controller - " - "can't loop the data"); + bytes_to_process += 24; + if (data_len < bytes_to_process) { + LOG(ERROR) << "Malformed LE extended advertising packet: not enough room " + "for metadata"; return; } @@ -1909,8 +1917,11 @@ void btm_ble_process_ext_adv_pkt(uint8_t data_len, uint8_t* data) { uint8_t* pkt_data = p; p += pkt_data_len; /* Advance to the the next packet*/ - if (p > data + data_len) { - LOG(ERROR) << "Invalid pkt_data_len: " << +pkt_data_len; + + bytes_to_process += pkt_data_len; + if (data_len < bytes_to_process) { + LOG(ERROR) << "Malformed LE extended advertising packet: not enough room " + "for packet data"; return; } @@ -1939,17 +1950,28 @@ void btm_ble_process_adv_pkt(uint8_t data_len, uint8_t* data) { uint8_t* p = data; uint8_t legacy_evt_type, addr_type, num_reports, pkt_data_len; int8_t rssi; + size_t bytes_to_process; /* Only process the results if the inquiry is still active */ if (!BTM_BLE_IS_SCAN_ACTIVE(btm_cb.ble_ctr_cb.scan_activity)) return; + bytes_to_process = 1; + + if (data_len < bytes_to_process) { + LOG(ERROR) + << "Malformed LE advertising packet: not enough room for num reports"; + return; + } + /* Extract the number of reports in this event. */ STREAM_TO_UINT8(num_reports, p); while (num_reports--) { - if (p > data + data_len) { - // TODO(jpawlowski): we should crash the stack here - BTM_TRACE_ERROR("Malformed LE Advertising Report Event from controller"); + bytes_to_process += 9; + + if (data_len < bytes_to_process) { + LOG(ERROR) + << "Malformed LE advertising packet: not enough room for metadata"; return; } @@ -1961,8 +1983,12 @@ void btm_ble_process_adv_pkt(uint8_t data_len, uint8_t* data) { uint8_t* pkt_data = p; p += pkt_data_len; /* Advance to the the rssi byte */ - if (p > data + data_len - sizeof(rssi)) { - LOG(ERROR) << "Invalid pkt_data_len: " << +pkt_data_len; + + // include rssi for this check + bytes_to_process += pkt_data_len + 1; + if (data_len < bytes_to_process) { + LOG(ERROR) << "Malformed LE advertising packet: not enough room for " + "packet data and/or RSSI"; return; } diff --git a/stack/btu/btu_hcif.cc b/stack/btu/btu_hcif.cc index 15227cb1b..279c9d930 100644 --- a/stack/btu/btu_hcif.cc +++ b/stack/btu/btu_hcif.cc @@ -1776,6 +1776,12 @@ static void btu_ble_data_length_change_evt(uint8_t* p, uint16_t evt_len) { return; } + // 2 bytes each for handle, tx_data_len, TxTimer, rx_data_len + if (evt_len < 8) { + LOG_ERROR(LOG_TAG, "Event packet too short"); + return; + } + STREAM_TO_UINT16(handle, p); STREAM_TO_UINT16(tx_data_len, p); p += 2; /* Skip the TxTimer */