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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 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 │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/bits/safemacros.h"
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/conv/conv.h"
#include "libc/conv/itoa.h"
#include "libc/log/asan.h"
#include "libc/log/backtrace.h"
#include "libc/log/log.h"
#include "libc/macros.h"
#include "libc/mem/hook/hook.h"
#include "libc/runtime/directmap.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/memtrack.h"
#include "libc/runtime/missioncritical.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/symbols.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/fileno.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "third_party/dlmalloc/dlmalloc.h"
/**
* @fileoverview Cosmopolitan Address Sanitizer Runtime.
*
* Someone brilliant at Google figured out a way to improve upon memory
* protection. Rather than invent another Java or Rust they changed GCC
* so it can emit fast code, that checks the validity of each memory op
* with byte granularity, by probing shadow memory.
*
* AddressSanitizer dedicates one-eighth of the virtual address space
* to its shadow memory and uses a direct mapping with a scale and
* offset to translate an application address to its corresponding
* shadow address. Given the application memory address Addr, the
* address of the shadow byte is computed as (Addr>>3)+Offset."
*
* We use the following encoding for each shadow byte: 0 means that
* all 8 bytes of the corresponding application memory region are
* addressable; k (1 ≤ k ≤ 7) means that the first k bytes are
* addressible; any negative value indicates that the entire 8-byte
* word is unaddressable. We use different negative values to
* distinguish between different kinds of unaddressable memory (heap
* redzones, stack redzones, global redzones, freed memory).
*
* Here's what the generated code looks like for 64-bit reads:
*
* movq %addr,%tmp
* shrq $3,%tmp
* cmpb $0,0x7fff8000(%tmp)
* jnz abort
* movq (%addr),%dst
*/
#define HOOK(HOOK, IMPL) \
if (weaken(HOOK)) { \
*weaken(HOOK) = IMPL; \
}
struct AsanSourceLocation {
const char *filename;
int line;
int column;
};
struct AsanAccessInfo {
const char *addr;
const char *first_bad_addr;
size_t size;
bool iswrite;
unsigned long ip;
};
struct AsanGlobal {
const char *addr;
size_t size;
size_t size_with_redzone;
const void *name;
const void *module_name;
unsigned long has_cxx_init;
struct AsanSourceLocation *location;
char *odr_indicator;
};
struct AsanMorgue {
unsigned i;
void *p[16];
};
static struct AsanMorgue __asan_morgue;
static const char *__asan_dscribe_free_poison(int c) {
switch (c) {
case kAsanHeapFree:
return "heap double free";
case kAsanRelocated:
return "free after relocate";
case kAsanStackFree:
return "stack double free";
default:
return "invalid pointer";
}
}
static const char *__asan_describe_access_poison(int c) {
switch (c) {
case kAsanHeapFree:
return "heap use after free";
case kAsanStackFree:
return "stack use after release";
case kAsanRelocated:
return "heap use after relocate";
case kAsanHeapUnderrun:
return "heap underrun";
case kAsanHeapOverrun:
return "heap overrun";
case kAsanGlobalOverrun:
return "global overrun";
case kAsanGlobalUnregistered:
return "global unregistered";
case kAsanStackUnderrun:
return "stack underflow";
case kAsanStackOverrun:
return "stack overflow";
case kAsanAllocaOverrun:
return "alloca overflow";
case kAsanUnscoped:
return "unscoped";
default:
return "poisoned";
}
}
static noreturn void __asan_die(const char *msg, size_t size) {
__print(msg, size);
PrintBacktraceUsingSymbols(stderr, __builtin_frame_address(0),
getsymboltable());
DebugBreak();
_Exit(66);
}
static noreturn void __asan_report_deallocate_fault(void *addr, int c) {
char *p, ibuf[21], buf[256];
p = buf;
p = stpcpy(p, "error: ");
p = stpcpy(p, __asan_dscribe_free_poison(c));
p = stpcpy(p, " ");
p = mempcpy(p, ibuf, int64toarray_radix10(c, ibuf));
p = stpcpy(p, " at 0x");
p = mempcpy(p, ibuf, uint64toarray_fixed16((intptr_t)addr, ibuf, 48));
p = stpcpy(p, "\n");
__asan_die(buf, p - buf);
}
static noreturn void __asan_report_memory_fault(uint8_t *addr, int size,
const char *kind) {
char *p, ibuf[21], buf[256];
p = buf;
p = stpcpy(p, "error: ");
p = stpcpy(p, __asan_describe_access_poison(*(char *)SHADOW((intptr_t)addr)));
p = stpcpy(p, " ");
p = mempcpy(p, ibuf, uint64toarray_radix10(size, ibuf));
p = stpcpy(p, "-byte ");
p = stpcpy(p, kind);
p = stpcpy(p, " at 0x");
p = mempcpy(p, ibuf, uint64toarray_fixed16((intptr_t)addr, ibuf, 48));
p = stpcpy(p, "\n");
__asan_die(buf, p - buf);
}
static const void *__asan_morgue_add(void *p) {
void *r;
r = __asan_morgue.p[__asan_morgue.i];
__asan_morgue.p[__asan_morgue.i] = p;
__asan_morgue.i += 1;
__asan_morgue.i &= ARRAYLEN(__asan_morgue.p) - 1;
return r;
}
static void __asan_morgue_flush(void) {
void *p;
unsigned i;
for (i = 0; i < ARRAYLEN(__asan_morgue.p); ++i) {
p = __asan_morgue.p[i];
__asan_morgue.p[i] = NULL;
dlfree(p);
}
}
static bool __asan_is_mapped(void *p) {
int x, i;
x = (intptr_t)p >> 16;
i = FindMemoryInterval(&_mmi, x);
return i < _mmi.i && x >= _mmi.p[i].x && x <= _mmi.p[i].y;
}
static void *__asan_allocate(size_t align, size_t size, int underrun,
int overrun) {
char *p, *s;
size_t q, r, i;
if (!(p = dlmemalign(align, ROUNDUP(size, 8) + 16))) return NULL;
s = (char *)SHADOW((intptr_t)p - 16);
q = size / 8;
r = size % 8;
*s++ = underrun;
*s++ = underrun;
memset(s, 0, q);
s += q;
if (r) *s++ = r;
*s++ = overrun;
*s++ = overrun;
return p;
}
static void __asan_deallocate(char *p, int kind) {
char *s;
s = (char *)SHADOW((intptr_t)p);
if ((*s < 0 && *s != kAsanHeapOverrun) || *s >= 8) {
__asan_report_deallocate_fault(p, *s);
}
memset(s, kind, dlmalloc_usable_size(p) >> 3);
dlfree(__asan_morgue_add(p));
}
static void __asan_poison_redzone(intptr_t addr, size_t size, size_t redsize,
int kind) {
char *s;
intptr_t p;
size_t a, b, w;
w = (intptr_t)addr & 7;
p = (intptr_t)addr - w;
a = w + size;
b = w + redsize;
s = (char *)SHADOW(p + a);
if (a & 7) *s++ = a & 7;
memset(s, kind, (b - ROUNDUP(a, 8)) >> 3);
}
static size_t __asan_malloc_usable_size(const void *vp) {
char *s;
size_t n;
for (n = 0, s = (char *)SHADOW((intptr_t)vp);; ++s) {
if (!*s) {
n += 8;
} else if (*s > 0) {
n += *s & 7;
} else {
break;
}
}
return n;
}
static void __asan_free(void *p) {
if (!p) return;
__asan_deallocate(p, kAsanHeapFree);
}
static void *__asan_memalign(size_t align, size_t size) {
return __asan_allocate(align, size, kAsanHeapUnderrun, kAsanHeapOverrun);
}
static void *__asan_malloc(size_t size) {
return __asan_memalign(16, size);
}
static void *__asan_calloc(size_t n, size_t m) {
char *p;
size_t size;
if (__builtin_mul_overflow(n, m, &size)) size = -1;
if ((p = __asan_malloc(size))) memset(p, 0, size);
return p;
}
static void *__asan_realloc(void *p, size_t n) {
char *p2;
if (p) {
if (n) {
if ((p2 = __asan_malloc(n))) {
memcpy(p2, p, min(n, dlmalloc_usable_size(p)));
__asan_deallocate(p, kAsanRelocated);
}
} else {
__asan_free(p);
p2 = NULL;
}
} else {
p2 = __asan_malloc(n);
}
return p2;
}
static void *__asan_valloc(size_t n) {
return __asan_memalign(PAGESIZE, n);
}
static void *__asan_pvalloc(size_t n) {
return __asan_valloc(ROUNDUP(n, PAGESIZE));
}
void __asan_register_globals(struct AsanGlobal g[], int n) {
unsigned i;
for (i = 0; i < n; ++i) {
__asan_poison_redzone((intptr_t)g[i].addr, g[i].size,
g[i].size_with_redzone, kAsanGlobalOverrun);
}
}
void __asan_unregister_globals(struct AsanGlobal g[], int n) {
unsigned i;
intptr_t a, b;
for (i = 0; i < n; ++i) {
a = ROUNDUP((intptr_t)g[i].addr, 8);
b = ROUNDDOWN((intptr_t)g[i].addr + g[i].size_with_redzone, 8);
if (b > a) {
memset((char *)SHADOW(a), kAsanGlobalUnregistered, (b - a) >> 3);
}
}
}
void *__asan_stack_malloc(size_t size, int classid) {
return __asan_allocate(32, size, kAsanStackUnderrun, kAsanStackOverrun);
}
void __asan_stack_free(char *p, size_t size, int classid) {
dlfree(p);
}
void __asan_report_load_n(uint8_t *addr, int size) {
__asan_report_memory_fault(addr, size, "load");
}
void __asan_report_store_n(uint8_t *addr, int size) {
__asan_report_memory_fault(addr, size, "store");
}
void __asan_poison_stack_memory(uintptr_t p, size_t n) {
memset((char *)SHADOW(p), kAsanUnscoped, n >> 3);
if (n & 7) *(char *)SHADOW(p + n) = 8 - (n & 7);
}
void __asan_unpoison_stack_memory(uintptr_t p, size_t n) {
memset((char *)SHADOW(p), 0, n >> 3);
if (n & 7) *(char *)SHADOW(p + n) = n & 7;
}
void __asan_alloca_poison(intptr_t addr, size_t size) {
__asan_poison_redzone(addr, size, size + 32, kAsanAllocaOverrun);
}
void __asan_allocas_unpoison(uintptr_t top, uintptr_t bottom) {
memset((char *)SHADOW(top), 0, (bottom - top) >> 3);
}
void *__asan_addr_is_in_fake_stack(void *fakestack, void *addr, void **beg,
void **end) {
return NULL;
}
void *__asan_get_current_fake_stack(void) {
return NULL;
}
void __asan_install_malloc_hooks(void) {
HOOK(hook$free, __asan_free);
HOOK(hook$malloc, __asan_malloc);
HOOK(hook$calloc, __asan_calloc);
HOOK(hook$valloc, __asan_valloc);
HOOK(hook$pvalloc, __asan_pvalloc);
HOOK(hook$realloc, __asan_realloc);
HOOK(hook$memalign, __asan_memalign);
HOOK(hook$malloc_usable_size, __asan_malloc_usable_size);
}
void __asan_map_shadow(void *addr, size_t size) {
int i, n, x;
char *a, *b;
struct DirectMap sm;
a = (char *)ROUNDDOWN(SHADOW((intptr_t)addr), FRAMESIZE);
b = (char *)ROUNDDOWN(SHADOW((intptr_t)addr + size - 1), FRAMESIZE);
for (; a <= b; a += FRAMESIZE) {
if (!__asan_is_mapped(a)) {
sm = DirectMap(a, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
if (sm.addr == MAP_FAILED ||
TrackMemoryInterval(&_mmi, (intptr_t)a >> 16, (intptr_t)a >> 16,
sm.maphandle) == -1) {
abort();
}
}
}
}
textstartup void __asan_init(int argc, char *argv[], char **envp,
intptr_t *auxv) {
int i;
static bool once;
register intptr_t rsp asm("rsp");
if (!once) {
__asan_map_shadow(_base, _end - _base);
__asan_map_shadow((void *)ROUNDDOWN(rsp, STACKSIZE), STACKSIZE);
for (i = 0; i < argc; ++i) __asan_map_shadow(argv[i], strlen(argv[i]));
for (; *envp; ++envp) __asan_map_shadow(*envp, strlen(*envp));
__asan_map_shadow(auxv, sizeof(intptr_t) * 2);
__asan_install_malloc_hooks();
once = true;
}
}
static textstartup void __asan_ctor(void) {
/* __cxa_atexit(__asan_morgue_flush, NULL, NULL); */
getsymboltable();
}
const void *const g_asan_ctor[] initarray = {__asan_ctor};