| Peter Collingbourne | 5d3aa86 | 2020-09-11 15:05:17 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2020 The Android Open Source Project |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * * Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * * Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in |
| 12 | * the documentation and/or other materials provided with the |
| 13 | * distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 16 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 17 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| 18 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| 19 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| 21 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| 22 | * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| 23 | * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| 24 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| 25 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 26 | * SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #include "memory_mitigation_state.h" |
| 30 | |
| 31 | #include <dirent.h> |
| 32 | #include <pthread.h> |
| 33 | #include <semaphore.h> |
| 34 | #include <stdatomic.h> |
| 35 | #include <stdlib.h> |
| 36 | #include <sys/prctl.h> |
| 37 | #include <sys/types.h> |
| 38 | |
| 39 | #include <bionic/mte.h> |
| 40 | #include <bionic/reserved_signals.h> |
| 41 | |
| 42 | #include "private/ScopedRWLock.h" |
| 43 | #include "pthread_internal.h" |
| 44 | |
| 45 | extern "C" void scudo_malloc_set_zero_contents(int zero_contents); |
| 46 | extern "C" void scudo_malloc_disable_memory_tagging(); |
| 47 | |
| 48 | #ifdef ANDROID_EXPERIMENTAL_MTE |
| 49 | static bool set_tcf_on_all_threads(int tcf) { |
| 50 | static int g_tcf; |
| 51 | g_tcf = tcf; |
| 52 | |
| 53 | return android_run_on_all_threads( |
| 54 | [](void*) { |
| 55 | int tagged_addr_ctrl = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0); |
| 56 | if (tagged_addr_ctrl < 0) { |
| 57 | return false; |
| 58 | } |
| 59 | |
| 60 | tagged_addr_ctrl = (tagged_addr_ctrl & ~PR_MTE_TCF_MASK) | g_tcf; |
| 61 | if (prctl(PR_SET_TAGGED_ADDR_CTRL, tagged_addr_ctrl, 0, 0, 0) < 0) { |
| 62 | return false; |
| 63 | } |
| 64 | return true; |
| 65 | }, |
| 66 | nullptr); |
| 67 | } |
| 68 | #endif |
| 69 | |
| 70 | bool DisableMemoryMitigations(void* arg, size_t arg_size) { |
| 71 | if (arg || arg_size) { |
| 72 | return false; |
| 73 | } |
| 74 | |
| 75 | #ifdef USE_SCUDO |
| 76 | scudo_malloc_set_zero_contents(0); |
| 77 | |
| 78 | #ifdef ANDROID_EXPERIMENTAL_MTE |
| 79 | if (mte_supported() && set_tcf_on_all_threads(PR_MTE_TCF_NONE)) { |
| 80 | scudo_malloc_disable_memory_tagging(); |
| 81 | } |
| 82 | #endif |
| 83 | #endif |
| 84 | |
| 85 | return true; |
| 86 | } |