| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include "heap_tagging.h" |
| #include "malloc_common.h" |
| #include "malloc_tagged_pointers.h" |
| |
| #include <platform/bionic/malloc.h> |
| #include <platform/bionic/mte_kernel.h> |
| |
| static HeapTaggingLevel heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE; |
| |
| void SetDefaultHeapTaggingLevel() { |
| // Allow the kernel to accept tagged pointers in syscall arguments. This is a no-op (kernel |
| // returns -EINVAL) if the kernel doesn't understand the prctl. |
| #if defined(__aarch64__) |
| #define PR_SET_TAGGED_ADDR_CTRL 55 |
| #define PR_TAGGED_ADDR_ENABLE (1UL << 0) |
| #ifdef ANDROID_EXPERIMENTAL_MTE |
| // First, try enabling MTE in asynchronous mode, with tag 0 excluded. This will fail if the kernel |
| // or hardware doesn't support MTE, and we will fall back to just enabling tagged pointers in |
| // syscall arguments. |
| if (prctl(PR_SET_TAGGED_ADDR_CTRL, |
| PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_ASYNC | (1 << PR_MTE_EXCL_SHIFT), 0, 0, 0) == 0) { |
| return; |
| } |
| #endif // ANDROID_EXPERIMENTAL_MTE |
| |
| if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0) { |
| heap_tagging_level = M_HEAP_TAGGING_LEVEL_TBI; |
| __libc_globals.mutate([](libc_globals* globals) { |
| globals->heap_pointer_tag = reinterpret_cast<uintptr_t>(POINTER_TAG) << TAG_SHIFT; |
| }); |
| } |
| #endif // aarch64 |
| } |
| |
| bool SetHeapTaggingLevel(void* arg, size_t arg_size) { |
| if (arg_size != sizeof(HeapTaggingLevel)) { |
| return false; |
| } |
| |
| auto tag_level = *reinterpret_cast<HeapTaggingLevel*>(arg); |
| switch (tag_level) { |
| case M_HEAP_TAGGING_LEVEL_NONE: |
| break; |
| case M_HEAP_TAGGING_LEVEL_TBI: |
| if (heap_tagging_level == M_HEAP_TAGGING_LEVEL_NONE) { |
| error_log( |
| "SetHeapTaggingLevel: re-enabling tagging after it was disabled is not supported"); |
| return false; |
| } |
| break; |
| default: |
| error_log("SetHeapTaggingLevel: unknown tagging level"); |
| return false; |
| } |
| heap_tagging_level = tag_level; |
| info_log("SetHeapTaggingLevel: tag level set to %d", tag_level); |
| |
| if (heap_tagging_level == M_HEAP_TAGGING_LEVEL_NONE && __libc_globals->heap_pointer_tag != 0) { |
| __libc_globals.mutate([](libc_globals* globals) { globals->heap_pointer_tag = 0; }); |
| } |
| |
| return true; |
| } |