71 lines
6.7 KiB
C
71 lines
6.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
||
│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8 :vi│
|
||
╞══════════════════════════════════════════════════════════════════════════════╡
|
||
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
||
│ │
|
||
│ This program is free software; you can redistribute it and/or modify │
|
||
│ it under the terms of the GNU General Public License as published by │
|
||
│ the Free Software Foundation; version 2 of the License. │
|
||
│ │
|
||
│ This program is distributed in the hope that it will be useful, but │
|
||
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
|
||
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
|
||
│ General Public License for more details. │
|
||
│ │
|
||
│ You should have received a copy of the GNU General Public License │
|
||
│ along with this program; if not, write to the Free Software │
|
||
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
|
||
│ 02110-1301 USA │
|
||
╠──────────────────────────────────────────────────────────────────────────────╣
|
||
│░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░█▀█░█▀█░▀█▀░█░█░█▀█░█░░░█░░░█░█░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░█▀█░█░▄░░█░░█░█░█▀█░█░░░█░░░▀█▀░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░▀░▀░▀▀▀░░▀░░▀▀▀░▀░▀░▀▀▀░▀▀▀░░▀░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░█▀█░█▀█░█▀█░▀█▀░█▀█░█▀█░█░░░█▀▀░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░█▀▀░█ █░██▀░░█░░█▀█░█▀█░█░░░█▀▀░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░▀░░░▀▀▀░▀░▀░░▀░░▀░▀░▀▀▀░▀▀▀░▀▀▀░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░│
|
||
│░░░░░░░█▀▀░█░█░█▀▀░█▀█░█░█░▀█▀░█▀█░█▀█░█░░█▀▀░░░░░░░░░░░░░░░░░░░░░░░░▄▄░░░▐█░░│
|
||
│░░░░░░░█▀▀░▄▀▄░█▀▀░█░▄░█░█░░█░░█▀█░█▀█░█░░█▀▀░░░░░░░░░░░░▄▄▄░░░▄██▄░░█▀░░░█░▄░│
|
||
│░░░░░░░▀▀▀░▀░▀░▀▀▀░▀▀▀░▀▀▀░░▀░░▀░▀░▀▀▀░▀▀░▀▀▀░░░░░░░░░░▄██▀█▌░██▄▄░░▐█▀▄░▐█▀░░│
|
||
│░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░▐█▀▀▌░░░▄▀▌░▌░█░▌░░▌░▌░░│
|
||
╠──────────────────────────────────────────────────────▌▀▄─▐──▀▄─▐▄─▐▄▐▄─▐▄─▐▄─│
|
||
│ αcτµαlly pδrταblε εxεcµταblε § post-initialization read-only │
|
||
╚─────────────────────────────────────────────────────────────────────────────*/
|
||
#include "libc/bits/safemacros.h"
|
||
#include "libc/bits/weaken.h"
|
||
#include "libc/calls/calls.h"
|
||
#include "libc/runtime/internal.h"
|
||
#include "libc/runtime/runtime.h"
|
||
#include "libc/sysv/consts/prot.h"
|
||
|
||
#define getaddr(section) ((intptr_t)weakaddr(section))
|
||
|
||
static textstartup void _piro_protect(intptr_t start, intptr_t end, int prot) {
|
||
ssize_t len = end - start;
|
||
if (len > 0 && start && start % PAGESIZE == 0 && len % PAGESIZE == 0) {
|
||
if (mprotect((void *)(unsigned long)start, len, prot) == -1) abort();
|
||
}
|
||
}
|
||
|
||
/**
|
||
* Protects memory initialized at startup.
|
||
* e.g. function hooks, unpacked data structures, etc.
|
||
*
|
||
* This is only performed for executables of nontrivial size. It won't
|
||
* break the build if the αpε linker script wasn't used. Test code is
|
||
* protected too, so we don't end up like Knight Capital.
|
||
*
|
||
* @param prot can have PROT_{NONE,READ,WRITE,EXEC}
|
||
* @see ape/ape.lds
|
||
* @see libc/_start.S
|
||
*/
|
||
textstartup void _piro(int prot) {
|
||
if (getaddr("main") < getaddr("__test_start")) {
|
||
_piro_protect(getaddr("__test_start"), getaddr("__test_end"), PROT_NONE);
|
||
}
|
||
_piro_protect(getaddr("__ro"), getaddr("_etext"), PROT_READ);
|
||
_piro_protect(getaddr("__piro_start"), getaddr("__piro_end"), prot);
|
||
}
|