commit f91dbe2985a7c6cc0c5eea698116b019c1985640
author Myles Watson <mylesgw@google.com> Thu Oct 29 13:05:21 2020 -0700
committer Myles Watson <mylesgw@google.com> Fri Oct 30 15:07:23 2020 +0000
tree 51e232fcc6ad8b5bee7bedf22c14c8c9e4776b8c
parent d7573f4fa9007ab7750edfc56305eea97c525cdb

ACL: Drop broadcasts

Bug: 169327567
Test: compiles
Tag: #security
Change-Id: Id4231fd7a142d630a2ada0f41a90e01afc011045
Merged-In: Id4231fd7a142d630a2ada0f41a90e01afc011045

hci/src/packet_fragmenter.cc

diff --git a/hci/src/packet_fragmenter.cc b/hci/src/packet_fragmenter.cc
index 3a1175e..4c8906e 100644
--- a/hci/src/packet_fragmenter.cc
+++ b/hci/src/packet_fragmenter.cc
@@ -35,10 +35,12 @@
 #define APPLY_START_FLAG(handle) (((handle)&0xCFFF) | 0x2000)
 #define SUB_EVENT(event) ((event)&MSG_SUB_EVT_MASK)
 #define GET_BOUNDARY_FLAG(handle) (((handle) >> 12) & 0x0003)
+#define GET_BROADCAST_FLAG(handle) (((handle) >> 14) & 0x0003)
 
 #define HANDLE_MASK 0x0FFF
 #define START_PACKET_BOUNDARY 2
 #define CONTINUATION_PACKET_BOUNDARY 1
+#define POINT_TO_POINT 0
 #define L2CAP_HEADER_SIZE 4
 
 // Our interface and callbacks
@@ -131,8 +133,16 @@
     CHECK(acl_length == packet->len - HCI_ACL_PREAMBLE_SIZE);
 
     uint8_t boundary_flag = GET_BOUNDARY_FLAG(handle);
+    uint8_t broadcast_flag = GET_BROADCAST_FLAG(handle);
     handle = handle & HANDLE_MASK;
 
+    if (broadcast_flag != POINT_TO_POINT) {
+      LOG_WARN(LOG_TAG, "dropping broadcast packet");
+      android_errorWriteLog(0x534e4554, "169327567");
+      buffer_allocator->free(packet);
+      return;
+    }
+
     if (boundary_flag == START_PACKET_BOUNDARY) {
       auto map_iter = partial_packets.find(handle);
       if (map_iter != partial_packets.end()) {