179 lines
6.7 KiB
C
179 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=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/calls/calls.h"
|
||
#include "libc/dce.h"
|
||
#include "libc/fmt/bing.h"
|
||
#include "libc/limits.h"
|
||
#include "libc/log/check.h"
|
||
#include "libc/log/log.h"
|
||
#include "libc/macros.h"
|
||
#include "libc/mem/mem.h"
|
||
#include "libc/runtime/sysconf.h"
|
||
#include "libc/str/str.h"
|
||
#include "libc/sysv/consts/map.h"
|
||
#include "libc/sysv/consts/prot.h"
|
||
#include "libc/testlib/testlib.h"
|
||
|
||
/* TODO(jart): DELETE */
|
||
|
||
struct TestMemoryStack g_testmem;
|
||
struct TestMemoryStack g_testmem_trash;
|
||
static struct TestAllocation g_testmem_scratch[2][8];
|
||
static const char kMemZero[1];
|
||
static bool g_atstartofpage;
|
||
|
||
static struct TestAllocation testmem_push(struct TestMemoryStack *stack,
|
||
struct TestAllocation entry) {
|
||
if (stack->i == stack->n) {
|
||
if (!grow(&stack->p, &stack->n, sizeof(struct TestAllocation), 0)) abort();
|
||
}
|
||
return (stack->p[stack->i++] = entry);
|
||
}
|
||
|
||
static struct TestAllocation testmem_pop(struct TestMemoryStack *stack) {
|
||
assert(stack->i > 0);
|
||
struct TestAllocation res = stack->p[--stack->i];
|
||
return res;
|
||
}
|
||
|
||
static void testmem_destroy(struct TestAllocation alloc) {
|
||
if (munmap(alloc.mapaddr, alloc.mapsize) == -1) perror("munmap"), die();
|
||
}
|
||
|
||
static struct TestAllocation talloc(size_t n) {
|
||
struct TestAllocation alloc;
|
||
if (n) {
|
||
while (g_testmem_trash.i) {
|
||
struct TestAllocation trash = testmem_pop(&g_testmem_trash);
|
||
if (n <= trash.usersize) {
|
||
return trash;
|
||
} else {
|
||
testmem_destroy(trash);
|
||
}
|
||
}
|
||
alloc.mapsize = ROUNDUP(n + PAGESIZE * 2, FRAMESIZE);
|
||
CHECK_NE(MAP_FAILED, (alloc.mapaddr = mapanon(alloc.mapsize)));
|
||
CHECK_NE(-1, mprotect(alloc.mapaddr, PAGESIZE, PROT_NONE));
|
||
CHECK_NE(-1, mprotect((char *)alloc.mapaddr + alloc.mapsize - PAGESIZE,
|
||
PAGESIZE, PROT_NONE));
|
||
alloc.useraddr = (char *)alloc.mapaddr + PAGESIZE;
|
||
alloc.usersize = alloc.mapsize - PAGESIZE * 2;
|
||
CHECK_GE(alloc.usersize, n);
|
||
return alloc;
|
||
} else {
|
||
alloc.mapaddr = (/*unconst*/ void *)kMemZero;
|
||
alloc.mapsize = 0;
|
||
alloc.useraddr = (/*unconst*/ void *)kMemZero;
|
||
alloc.usersize = 0;
|
||
return alloc;
|
||
}
|
||
}
|
||
|
||
static textstartup void testmem_init(void) {
|
||
g_testmem.p = g_testmem_scratch[0];
|
||
g_testmem.n = ARRAYLEN(g_testmem_scratch[0]);
|
||
g_testmem_trash.p = g_testmem_scratch[1];
|
||
g_testmem_trash.n = ARRAYLEN(g_testmem_scratch[1]);
|
||
}
|
||
|
||
const void *const testmem_ctor[] initarray = {testmem_init};
|
||
|
||
FIXTURE(testmemory, triggerOffByOneArrayErrors) {
|
||
/* automate testing buffer overflows *and* underflows */
|
||
g_atstartofpage = true;
|
||
}
|
||
|
||
/**
|
||
* Allocates memory with properties useful for testing.
|
||
*
|
||
* This returns a pointer 𝑝 where reading or writing to either 𝑝[-1] or
|
||
* 𝑝[𝑛+𝟷] will immediately trigger a segmentation fault; and bytes are
|
||
* initialized to 10100101 (A5).
|
||
*
|
||
* Implementation Details: Accomplishing this entails two things. First,
|
||
* we grant each allocation a page granular memory mapping, with access
|
||
* to the two adjacent pages disabled. Second, since hardware memory
|
||
* protection isn't 1-byte granular, we add a fixture so each test runs
|
||
* a second time; the first call we return a pointer where the data is
|
||
* placed on the righthand side, and the second call we return the data
|
||
* on the lefthand side, thereby allowing both underflow/overflow
|
||
* off-by-one out-of-bounds accesses to be detected.
|
||
*/
|
||
void *tmalloc(size_t n) {
|
||
struct TestAllocation alloc = talloc(n);
|
||
memset(alloc.useraddr, 0xa5, alloc.usersize);
|
||
testmem_push(&g_testmem, alloc);
|
||
return (char *)alloc.useraddr + (g_atstartofpage ? 0 : alloc.usersize - n);
|
||
}
|
||
|
||
/**
|
||
* Same as tmalloc() but guarantees a specific alignment.
|
||
*
|
||
* Reading or writing to either 𝑝[-1] or 𝑝[roundup(𝑛+𝟷,𝑎)] will
|
||
* immediately trigger a segmentation fault.
|
||
*
|
||
* @param 𝑎 is alignment in bytes, e.g. 16
|
||
* @param 𝑛 is number of bytes
|
||
*/
|
||
void *tmemalign(size_t a, size_t n) {
|
||
/* TODO(jart): ASAN detect 𝑝[𝑛+𝟷] */
|
||
return tmalloc(ROUNDUP(n, a));
|
||
}
|
||
|
||
/**
|
||
* Same as tunbing() w/ alignment guarantee.
|
||
*/
|
||
void *tunbinga(size_t a, const char16_t *binglyphs) {
|
||
size_t size;
|
||
EXPECT_NE(0, (size = strlen16(binglyphs)));
|
||
return unbingbuf(tmemalign(a, size), size, binglyphs, -1);
|
||
}
|
||
|
||
/**
|
||
* Decodes CP437 glyphs to bounds-checked binary buffer, e.g.
|
||
*
|
||
* char *mem = tunbing(u" ☺☻♥♦");
|
||
* EXPECT_EQ(0, memcmp("\0\1\2\3\4", mem, 5));
|
||
* tfree(mem);
|
||
*
|
||
* @see tunbing(), unbingstr(), unbing()
|
||
*/
|
||
void *tunbing(const char16_t *binglyphs) {
|
||
return tunbinga(1, binglyphs);
|
||
}
|
||
|
||
/**
|
||
* Frees memory allocated with tmalloc().
|
||
* This needs to be called in LIFO order.
|
||
* @param
|
||
*/
|
||
void(tfree)(void *p) {
|
||
struct TestAllocation alloc;
|
||
__tfree_check(p);
|
||
alloc = testmem_pop(&g_testmem);
|
||
if (alloc.mapsize) testmem_push(&g_testmem_trash, alloc);
|
||
}
|
||
|
||
char *tstrdup(const char *s) {
|
||
return strcpy(tmalloc(strlen(s) + 1), s);
|
||
}
|