448 lines
13 KiB
C
448 lines
13 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/weaken.h"
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#include "libc/calls/calls.h"
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#include "libc/conv/itoa.h"
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#include "libc/log/asan.h"
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#include "libc/log/backtrace.h"
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#include "libc/log/log.h"
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#include "libc/mem/hook/hook.h"
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#include "libc/runtime/directmap.h"
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#include "libc/runtime/memtrack.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/fileno.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/prot.h"
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#include "third_party/dlmalloc/dlmalloc.h"
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STATIC_YOINK("_init_asan");
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/**
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* @fileoverview Cosmopolitan Address Sanitizer Runtime.
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*
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* Someone brilliant at Google figured out a way to improve upon memory
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* protection. Rather than invent another Java or Rust they changed GCC
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* so it can emit fast code, that checks the validity of each memory op
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* with byte granularity, by probing shadow memory.
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*
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* AddressSanitizer dedicates one-eighth of the virtual address space
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* to its shadow memory and uses a direct mapping with a scale and
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* offset to translate an application address to its corresponding
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* shadow address. Given the application memory address Addr, the
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* address of the shadow byte is computed as (Addr>>3)+Offset."
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*
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* We use the following encoding for each shadow byte: 0 means that
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* all 8 bytes of the corresponding application memory region are
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* addressable; k (1 ≤ k ≤ 7) means that the first k bytes are
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* addressible; any negative value indicates that the entire 8-byte
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* word is unaddressable. We use different negative values to
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* distinguish between different kinds of unaddressable memory (heap
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* redzones, stack redzones, global redzones, freed memory).
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*
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* Here's what the generated code looks like for 64-bit reads:
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*
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* movq %addr,%tmp
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* shrq $3,%tmp
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* cmpb $0,0x7fff8000(%tmp)
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* jnz abort
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* movq (%addr),%dst
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*/
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#define HOOK(HOOK, IMPL) \
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if (weaken(HOOK)) { \
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*weaken(HOOK) = IMPL; \
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}
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struct AsanSourceLocation {
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const char *filename;
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int line;
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int column;
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};
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struct AsanAccessInfo {
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const char *addr;
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const char *first_bad_addr;
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size_t size;
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bool iswrite;
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unsigned long ip;
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};
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struct AsanGlobal {
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const char *addr;
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size_t size;
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size_t size_with_redzone;
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const void *name;
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const void *module_name;
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unsigned long has_cxx_init;
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struct AsanSourceLocation *location;
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char *odr_indicator;
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};
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struct AsanMorgue {
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unsigned i;
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void *p[16];
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};
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static struct AsanMorgue __asan_morgue;
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static const char *__asan_dscribe_free_poison(int c) {
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switch (c) {
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case kAsanHeapFree:
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return "heap double free";
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case kAsanRelocated:
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return "free after relocate";
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case kAsanStackFree:
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return "stack double free";
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default:
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return "invalid pointer";
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}
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}
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static const char *__asan_describe_access_poison(int c) {
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switch (c) {
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case kAsanHeapFree:
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return "heap use after free";
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case kAsanStackFree:
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return "stack use after release";
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case kAsanRelocated:
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return "heap use after relocate";
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case kAsanHeapUnderrun:
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return "heap underrun";
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case kAsanHeapOverrun:
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return "heap overrun";
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case kAsanGlobalOverrun:
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return "global overrun";
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case kAsanGlobalUnregistered:
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return "global unregistered";
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case kAsanStackUnderrun:
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return "stack underflow";
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case kAsanStackOverrun:
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return "stack overflow";
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case kAsanAllocaOverrun:
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return "alloca overflow";
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case kAsanUnscoped:
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return "unscoped";
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default:
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DebugBreak();
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return "poisoned";
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}
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}
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static noreturn void __asan_die(const char *msg, size_t size) {
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write(STDERR_FILENO, msg, size);
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die();
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}
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static char *__asan_report_start(char *p) {
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bool ansi;
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const char *term;
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term = getenv("TERM");
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ansi = !term || strcmp(term, "dumb") != 0;
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if (ansi) p = stpcpy(p, "\r\e[J\e[1;91m");
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p = stpcpy(p, "asan error");
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if (ansi) p = stpcpy(p, "\e[0m");
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return stpcpy(p, ": ");
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}
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static noreturn void __asan_report_deallocate_fault(void *addr, int c) {
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char *p, ibuf[21], buf[256];
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p = __asan_report_start(buf);
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p = stpcpy(p, __asan_dscribe_free_poison(c));
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p = stpcpy(p, " ");
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p = mempcpy(p, ibuf, int64toarray_radix10(c, ibuf));
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p = stpcpy(p, " at 0x");
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p = mempcpy(p, ibuf, uint64toarray_fixed16((intptr_t)addr, ibuf, 48));
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p = stpcpy(p, "\r\n");
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__asan_die(buf, p - buf);
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}
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static noreturn void __asan_report_memory_fault(uint8_t *addr, int size,
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const char *kind) {
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char *p, ibuf[21], buf[256];
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p = __asan_report_start(buf);
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p = stpcpy(p, __asan_describe_access_poison(*(char *)SHADOW((intptr_t)addr)));
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p = stpcpy(p, " ");
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p = mempcpy(p, ibuf, uint64toarray_radix10(size, ibuf));
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p = stpcpy(p, "-byte ");
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p = stpcpy(p, kind);
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p = stpcpy(p, " at 0x");
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p = mempcpy(p, ibuf, uint64toarray_fixed16((intptr_t)addr, ibuf, 48));
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p = stpcpy(p, "\r\n");
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__asan_die(buf, p - buf);
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}
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static const void *__asan_morgue_add(void *p) {
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void *r;
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r = __asan_morgue.p[__asan_morgue.i];
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__asan_morgue.p[__asan_morgue.i] = p;
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__asan_morgue.i += 1;
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__asan_morgue.i &= ARRAYLEN(__asan_morgue.p) - 1;
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return r;
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}
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static void __asan_morgue_flush(void) {
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void *p;
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unsigned i;
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for (i = 0; i < ARRAYLEN(__asan_morgue.p); ++i) {
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p = __asan_morgue.p[i];
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__asan_morgue.p[i] = NULL;
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dlfree(p);
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}
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}
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static void *__asan_allocate(size_t align, size_t size, int underrun,
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int overrun) {
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char *p, *s;
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size_t q, r, i;
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if (!(p = dlmemalign(align, ROUNDUP(size, 8) + 16))) return NULL;
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s = (char *)SHADOW((intptr_t)p - 16);
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q = size / 8;
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r = size % 8;
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*s++ = underrun;
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*s++ = underrun;
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memset(s, 0, q);
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s += q;
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if (r) *s++ = r;
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*s++ = overrun;
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*s++ = overrun;
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return p;
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}
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static void __asan_deallocate(char *p, int kind) {
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char *s;
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s = (char *)SHADOW((intptr_t)p);
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if ((*s < 0 && *s != kAsanHeapOverrun) || *s >= 8) {
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__asan_report_deallocate_fault(p, *s);
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}
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memset(s, kind, dlmalloc_usable_size(p) >> 3);
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dlfree(__asan_morgue_add(p));
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}
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static void __asan_poison_redzone(intptr_t addr, size_t size, size_t redsize,
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int kind) {
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char *s;
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intptr_t p;
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size_t a, b, w;
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w = (intptr_t)addr & 7;
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p = (intptr_t)addr - w;
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a = w + size;
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b = w + redsize;
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s = (char *)SHADOW(p + a);
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if (a & 7) *s++ = a & 7;
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memset(s, kind, (b - ROUNDUP(a, 8)) >> 3);
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}
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static size_t __asan_malloc_usable_size(const void *vp) {
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char *s;
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size_t n;
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for (n = 0, s = (char *)SHADOW((intptr_t)vp);; ++s) {
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if (!*s) {
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n += 8;
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} else if (*s > 0) {
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n += *s & 7;
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} else {
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break;
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}
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}
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return n;
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}
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static void __asan_free(void *p) {
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if (!p) return;
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__asan_deallocate(p, kAsanHeapFree);
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}
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static void *__asan_memalign(size_t align, size_t size) {
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return __asan_allocate(align, size, kAsanHeapUnderrun, kAsanHeapOverrun);
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}
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static void *__asan_malloc(size_t size) {
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return __asan_memalign(16, size);
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}
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static void *__asan_calloc(size_t n, size_t m) {
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char *p;
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size_t size;
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if (__builtin_mul_overflow(n, m, &size)) size = -1;
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if ((p = __asan_malloc(size))) memset(p, 0, size);
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return p;
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}
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static void *__asan_realloc(void *p, size_t n) {
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char *p2;
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if (p) {
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if (n) {
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if ((p2 = __asan_malloc(n))) {
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memcpy(p2, p, min(n, dlmalloc_usable_size(p)));
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__asan_deallocate(p, kAsanRelocated);
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}
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} else {
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__asan_free(p);
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p2 = NULL;
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}
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} else {
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p2 = __asan_malloc(n);
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}
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return p2;
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}
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static void *__asan_valloc(size_t n) {
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return __asan_memalign(PAGESIZE, n);
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}
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static void *__asan_pvalloc(size_t n) {
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return __asan_valloc(ROUNDUP(n, PAGESIZE));
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}
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void __asan_register_globals(struct AsanGlobal g[], int n) {
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unsigned i;
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for (i = 0; i < n; ++i) {
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__asan_poison_redzone((intptr_t)g[i].addr, g[i].size,
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g[i].size_with_redzone, kAsanGlobalOverrun);
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}
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}
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void __asan_unregister_globals(struct AsanGlobal g[], int n) {
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unsigned i;
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intptr_t a, b;
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for (i = 0; i < n; ++i) {
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a = ROUNDUP((intptr_t)g[i].addr, 8);
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b = ROUNDDOWN((intptr_t)g[i].addr + g[i].size_with_redzone, 8);
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if (b > a) {
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memset((char *)SHADOW(a), kAsanGlobalUnregistered, (b - a) >> 3);
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}
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}
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}
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void *__asan_stack_malloc(size_t size, int classid) {
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return __asan_allocate(32, size, kAsanStackUnderrun, kAsanStackOverrun);
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}
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void __asan_stack_free(char *p, size_t size, int classid) {
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dlfree(p);
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}
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void __asan_report_load_n(uint8_t *addr, int size) {
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__asan_report_memory_fault(addr, size, "load");
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}
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void __asan_report_store_n(uint8_t *addr, int size) {
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__asan_report_memory_fault(addr, size, "store");
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}
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void __asan_poison_stack_memory(uintptr_t p, size_t n) {
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memset((char *)SHADOW(p), kAsanUnscoped, n >> 3);
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if (n & 7) *(char *)SHADOW(p + n) = 8 - (n & 7);
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}
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void __asan_unpoison_stack_memory(uintptr_t p, size_t n) {
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memset((char *)SHADOW(p), 0, n >> 3);
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if (n & 7) *(char *)SHADOW(p + n) = n & 7;
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}
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void __asan_alloca_poison(intptr_t addr, size_t size) {
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__asan_poison_redzone(addr, size, size + 32, kAsanAllocaOverrun);
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}
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void __asan_allocas_unpoison(uintptr_t top, uintptr_t bottom) {
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memset((char *)SHADOW(top), 0, (bottom - top) >> 3);
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}
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void *__asan_addr_is_in_fake_stack(void *fakestack, void *addr, void **beg,
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void **end) {
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return NULL;
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}
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void *__asan_get_current_fake_stack(void) {
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return NULL;
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}
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void __asan_install_malloc_hooks(void) {
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HOOK(hook$free, __asan_free);
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HOOK(hook$malloc, __asan_malloc);
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HOOK(hook$calloc, __asan_calloc);
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HOOK(hook$valloc, __asan_valloc);
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HOOK(hook$pvalloc, __asan_pvalloc);
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HOOK(hook$realloc, __asan_realloc);
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HOOK(hook$memalign, __asan_memalign);
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HOOK(hook$malloc_usable_size, __asan_malloc_usable_size);
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}
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static bool __asan_is_mapped(int x) {
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int i = FindMemoryInterval(&_mmi, x);
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return i < _mmi.i && x >= _mmi.p[i].x && x <= _mmi.p[i].y;
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}
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void __asan_map_shadow(void *p, size_t n) {
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int i, x, a, b;
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struct DirectMap sm;
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a = SHADOW((uintptr_t)p) >> 16;
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b = ROUNDUP(SHADOW(ROUNDUP((uintptr_t)p + n, 8)), 1 << 16) >> 16;
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for (; a < b; ++a) {
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if (!__asan_is_mapped(a)) {
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sm = DirectMap((void *)((uintptr_t)a << 16), 1 << 16,
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PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
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if (sm.addr == MAP_FAILED ||
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TrackMemoryInterval(&_mmi, a, a, sm.maphandle, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED) == -1) {
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abort();
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}
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}
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}
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}
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static char *__asan_get_stack_base(void) {
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register uintptr_t rsp asm("rsp");
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return (char *)ROUNDDOWN(ROUNDDOWN(rsp, STACKSIZE), FRAMESIZE);
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}
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static textstartup size_t __asan_get_auxv_size(intptr_t *auxv) {
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unsigned i;
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for (i = 0;; i += 2) {
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if (!auxv[i]) break;
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}
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return (i + 2) * sizeof(intptr_t);
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}
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static textstartup void __asan_shadow_string_list(char **list) {
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for (; *list; ++list) {
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__asan_map_shadow(*list, strlen(*list) + 1);
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}
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}
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textstartup void __asan_init(int argc, char **argv, char **envp,
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intptr_t *auxv) {
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static bool once;
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if (once) return;
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__asan_map_shadow(_base, _end - _base);
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__asan_map_shadow(__asan_get_stack_base(), STACKSIZE);
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__asan_shadow_string_list(argv);
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__asan_shadow_string_list(envp);
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__asan_map_shadow(auxv, __asan_get_auxv_size(auxv));
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__asan_install_malloc_hooks();
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}
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static textstartup void __asan_ctor(void) {
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__cxa_atexit(__asan_morgue_flush, NULL, NULL);
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}
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const void *const g_asan_ctor[] initarray = {__asan_ctor};
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