platform_bionic/libc/private/bionic_globals.h
Mitch Phillips 43d5f9d4dd Add tagged pointers to bionic.
This patch introduces tagged pointers to bionic. We add a static tag to
all pointers on arm64 compatible platforms (needs requisite
top-byte-ignore hardware feature and relevant kernel patches).

We dynamically detect TBI-compatible devices (a device with the TBI feature and
kernel support) at process start time, and insert an implementation-dependent
tag into the top byte of the pointer for all heap allocations. We then check
that the tag has not been truncated when deallocating the memory.

If an application incorrectly writes to the top byte of the pointer, we
terminate the process at time of detection. This will allow MTE-incompatible
applications to be caught early.

Bug: 135754954
Bug: 147147490

Test: cd bionic && atest .
Change-Id: I6e5b809fc81f55dd517f845eaf20f3c0ebd4d86e
2020-01-15 15:03:00 -08:00

114 lines
4.5 KiB
C++

/*
* Copyright (C) 2015 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.
*/
#ifndef _PRIVATE_BIONIC_GLOBALS_H
#define _PRIVATE_BIONIC_GLOBALS_H
#include <stdatomic.h>
#include <sys/cdefs.h>
#include <link.h>
#include <pthread.h>
#include "private/bionic_allocator.h"
#include "private/bionic_elf_tls.h"
#include "private/bionic_fdsan.h"
#include "private/bionic_malloc_dispatch.h"
#include "private/bionic_vdso.h"
#include "private/WriteProtected.h"
struct libc_globals {
vdso_entry vdso[VDSO_END];
long setjmp_cookie;
uintptr_t heap_pointer_tag;
// In order to allow a complete switch between dispatch tables without
// the need for copying each function by function in the structure,
// use a single atomic pointer to switch.
// The current_dispatch_table pointer can only ever be set to a complete
// table. Any dispatch table that is pointed to by current_dispatch_table
// cannot be modified after that. If the pointer changes in the future,
// the old pointer must always stay valid.
// The malloc_dispatch_table is modified by malloc debug, malloc hooks,
// and heaprofd. Only one of these modes can be active at any given time.
_Atomic(const MallocDispatch*) current_dispatch_table;
// This pointer is only used by the allocation limit code when both a
// limit is enabled and some other hook is enabled at the same time.
_Atomic(const MallocDispatch*) default_dispatch_table;
MallocDispatch malloc_dispatch_table;
};
__LIBC_HIDDEN__ extern WriteProtected<libc_globals> __libc_globals;
struct abort_msg_t;
// Globals shared between the dynamic linker and libc.so.
struct libc_shared_globals {
// Construct the shared globals using a constexpr constructor to ensure that
// the object doesn't need dynamic initialization. The object is accessed
// before the dynamic linker has relocated itself.
constexpr libc_shared_globals() {}
FdTable fd_table;
// When the linker is invoked on a binary (e.g. `linker64 /system/bin/date`),
// record the number of arguments passed to the linker itself rather than to
// the program it's loading. Typically 0, sometimes 1.
int initial_linker_arg_count = 0;
ElfW(auxv_t)* auxv = nullptr;
pthread_mutex_t abort_msg_lock = PTHREAD_MUTEX_INITIALIZER;
abort_msg_t* abort_msg = nullptr;
StaticTlsLayout static_tls_layout;
TlsModules tls_modules;
BionicAllocator tls_allocator;
// Values passed from the HWASan runtime (via libc.so) to the loader.
void (*load_hook)(ElfW(Addr) base, const ElfW(Phdr)* phdr, ElfW(Half) phnum) = nullptr;
void (*unload_hook)(ElfW(Addr) base, const ElfW(Phdr)* phdr, ElfW(Half) phnum) = nullptr;
// Values passed from the linker to libc.so.
const char* init_progname = nullptr;
char** init_environ = nullptr;
};
__LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals();
__LIBC_HIDDEN__ void __libc_init_fdsan();
__LIBC_HIDDEN__ void __libc_init_malloc(libc_globals* globals);
__LIBC_HIDDEN__ void __libc_init_setjmp_cookie(libc_globals* globals);
__LIBC_HIDDEN__ void __libc_init_vdso(libc_globals* globals);
#if defined(__i386__)
__LIBC_HIDDEN__ extern void* __libc_sysinfo;
__LIBC_HIDDEN__ void __libc_int0x80();
__LIBC_HIDDEN__ void __libc_init_sysinfo();
#endif
#endif