b6453c52ac
Before, dynamic executables would initialize the global stack protector twice, once for the linker, and once for the executable. This worked because the result was the same for both initializations, because it used getauxval(AT_RANDOM), which won't be the case once arc4random gets used for it. Bug: http://b/29622562 Change-Id: I7718b1ba8ee8fac7127ab2360cb1088e510fef5c Test: ran the stack protector tests on angler (32/64bit, static/dynamic)
115 lines
4.1 KiB
C++
115 lines
4.1 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <android/api-level.h>
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#include <elf.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/auxv.h>
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#include <sys/mman.h>
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#include "libc_init_common.h"
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#include "pthread_internal.h"
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#include "private/bionic_globals.h"
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#include "private/bionic_page.h"
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#include "private/bionic_tls.h"
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#include "private/KernelArgumentBlock.h"
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extern "C" int __cxa_atexit(void (*)(void *), void *, void *);
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static void call_array(void(**list)()) {
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// First element is -1, list is null-terminated
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while (*++list) {
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(*list)();
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}
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}
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static void apply_gnu_relro() {
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ElfW(Phdr)* phdr_start = reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR));
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unsigned long int phdr_ct = getauxval(AT_PHNUM);
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for (ElfW(Phdr)* phdr = phdr_start; phdr < (phdr_start + phdr_ct); phdr++) {
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if (phdr->p_type != PT_GNU_RELRO) {
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continue;
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}
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ElfW(Addr) seg_page_start = PAGE_START(phdr->p_vaddr);
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ElfW(Addr) seg_page_end = PAGE_END(phdr->p_vaddr + phdr->p_memsz);
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// Check return value here? What do we do if we fail?
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mprotect(reinterpret_cast<void*>(seg_page_start), seg_page_end - seg_page_start, PROT_READ);
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}
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}
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// The program startup function __libc_init() defined here is
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// used for static executables only (i.e. those that don't depend
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// on shared libraries). It is called from arch-$ARCH/bionic/crtbegin_static.S
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// which is directly invoked by the kernel when the program is launched.
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//
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// The 'structors' parameter contains pointers to various initializer
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// arrays that must be run before the program's 'main' routine is launched.
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__noreturn void __libc_init(void* raw_args,
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void (*onexit)(void) __unused,
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int (*slingshot)(int, char**, char**),
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structors_array_t const * const structors) {
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KernelArgumentBlock args(raw_args);
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__libc_init_main_thread(args);
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// Initializing the globals requires TLS to be available for errno.
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__init_thread_stack_guard(__get_thread());
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__libc_init_globals(args);
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__libc_init_AT_SECURE(args);
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__libc_init_common(args);
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apply_gnu_relro();
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// Several Linux ABIs don't pass the onexit pointer, and the ones that
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// do never use it. Therefore, we ignore it.
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call_array(structors->preinit_array);
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call_array(structors->init_array);
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// The executable may have its own destructors listed in its .fini_array
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// so we need to ensure that these are called when the program exits
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// normally.
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if (structors->fini_array != NULL) {
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__cxa_atexit(__libc_fini,structors->fini_array,NULL);
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}
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exit(slingshot(args.argc, args.argv, args.envp));
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}
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uint32_t bionic_get_application_target_sdk_version() {
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return __ANDROID_API__;
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}
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