cosmopolitan/test/libc/runtime/mprotect_test.c
Justine Tunney 7e0a09feec
Mint APE Loader v1.5
This change ports APE Loader to Linux AARCH64, so that Raspberry Pi
users can run programs like redbean, without the executable needing
to modify itself. Progress has also slipped into this change on the
issue of making progress better conforming to user expectations and
industry standards regarding which symbols we're allowed to declare
2023-07-26 13:54:49 -07:00

236 lines
8.8 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 2021 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/ucontext.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/fmt/fmt.h"
#include "libc/log/log.h"
#include "libc/mem/gc.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/testlib/testlib.h"
#include "libc/x/x.h"
#include "third_party/xed/x86.h"
volatile bool gotsegv;
volatile bool gotbusted;
struct sigaction old[2];
char testlib_enable_tmp_setup_teardown;
#ifdef __x86_64__
static const char kRet31337[] = {
0xb8, 0x69, 0x7a, 0x00, 0x00, // mov $31337,%eax
0xc3, // ret
};
#elif defined(__aarch64__)
static const uint32_t kRet31337[] = {
0x528f4d20, // mov w0,#31337
0xd65f03c0, // ret
};
#else
#error "unsupported architecture"
#endif
void SkipOverFaultingInstruction(struct ucontext *ctx) {
#ifdef __x86_64__
struct XedDecodedInst xedd;
xed_decoded_inst_zero_set_mode(&xedd, XED_MACHINE_MODE_LONG_64);
xed_instruction_length_decode(&xedd, (void *)ctx->uc_mcontext.rip, 15);
ctx->uc_mcontext.rip += xedd.length;
#elif defined(__aarch64__)
ctx->uc_mcontext.pc += 4;
#else
#error "unsupported architecture"
#endif
}
void OnSigSegv(int sig, struct siginfo *si, void *vctx) {
struct ucontext *ctx = vctx;
gotsegv = true;
SkipOverFaultingInstruction(ctx);
}
void OnSigBus(int sig, struct siginfo *si, void *vctx) {
struct ucontext *ctx = vctx;
gotbusted = true;
SkipOverFaultingInstruction(ctx);
#if 0
kprintf("SIGBUS%n");
kprintf("si->si_signo = %G%n", si->si_signo);
kprintf("si->si_errno = %s (%d)%n", _strerrno(si->si_errno),
si->si_errno);
kprintf("si->si_code = %s (%d)%n", GetSiCodeName(sig, si->si_code),
si->si_code);
kprintf("┌si->si_addr = %p%n", si->si_addr);
kprintf("┼─────────────────%n");
kprintf("│si->si_pid = %d (note: getpid() is %d)%n", si->si_pid, getpid());
kprintf("│si->si_uid = %d%n", si->si_uid);
kprintf("┼─────────────────%n");
kprintf("│si->si_timerid = %d%n", si->si_timerid);
kprintf("└si->si_overrun = %d%n", si->si_overrun);
kprintf("si->si_value.sival_int = %d%n", si->si_value.sival_int);
kprintf("si->si_value.sival_ptr = %p%n", si->si_value.sival_ptr);
system(xasprintf("cat /proc/%d/map", getpid()));
#endif
}
void SetUp(void) {
struct sigaction sabus = {.sa_sigaction = OnSigBus,
.sa_flags = SA_SIGINFO | SA_RESETHAND};
struct sigaction sasegv = {.sa_sigaction = OnSigSegv,
.sa_flags = SA_SIGINFO | SA_RESETHAND};
sigaction(SIGBUS, &sabus, old + 0);
sigaction(SIGSEGV, &sasegv, old + 1);
gotbusted = false;
gotsegv = false;
}
void TearDown(void) {
sigaction(SIGBUS, old + 0, 0);
sigaction(SIGSEGV, old + 1, 0);
}
TEST(mprotect, testOkMemory) {
char *p = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
p[0] = 0;
ASSERT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ | PROT_WRITE));
p[0] = 1;
EXPECT_EQ(1, p[0]);
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
}
TEST(mprotect, testSegfault_writeToReadOnlyAnonymous) {
volatile char *p;
p = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
EXPECT_FALSE(gotsegv);
p[0] = 1;
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ));
_missingno(p[0]);
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
p[0] = 2;
EXPECT_TRUE(gotsegv | gotbusted);
EXPECT_EQ(1, p[0]);
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ | PROT_WRITE));
}
TEST(mprotect, testExecOnly_canExecute) {
char *p = _mapanon(FRAMESIZE);
void (*f)(void) = (void *)p;
memcpy(p, kRet31337, sizeof(kRet31337));
ASSERT_SYS(0, 0, mprotect(p, FRAMESIZE, PROT_EXEC | PROT_READ));
f();
// On all supported platforms, PROT_EXEC implies PROT_READ. There is
// one exception to this rule: Chromebook's fork of the Linux kernel
// which has been reported, to have the ability to prevent a program
// from reading its own code.
ASSERT_SYS(0, 0, mprotect(p, FRAMESIZE, PROT_EXEC));
f();
munmap(p, FRAMESIZE);
}
TEST(mprotect, testProtNone_cantEvenRead) {
volatile char *p;
p = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_NONE));
_missingno(p[0]);
EXPECT_TRUE(gotsegv | gotbusted);
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ | PROT_WRITE));
}
TEST(mprotect, testExecJit_actuallyWorks) {
int (*p)(void) = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
memcpy(p, kRet31337, sizeof(kRet31337));
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_EXEC));
EXPECT_EQ(31337, p());
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ | PROT_WRITE));
}
TEST(mprotect, testRwxMap_vonNeumannRules) {
if (IsOpenbsd()) return; // boo
if (IsXnuSilicon()) return; // boo
int (*p)(void) = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
memcpy(p, kRet31337, sizeof(kRet31337));
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ),
PROT_READ | PROT_WRITE | PROT_EXEC));
EXPECT_EQ(31337, p());
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
EXPECT_NE(-1, mprotect(p, getauxval(AT_PAGESZ), PROT_READ | PROT_WRITE));
}
TEST(mprotect, testExecuteFlatFileMapOpenedAsReadonly) {
int (*p)(void);
size_t n = sizeof(kRet31337);
ASSERT_SYS(0, 3, creat("return31337", 0755));
ASSERT_SYS(0, n, write(3, kRet31337, n));
ASSERT_SYS(0, 0, close(3));
ASSERT_SYS(0, 3, open("return31337", O_RDONLY));
EXPECT_NE(MAP_FAILED,
(p = mmap(NULL, n, PROT_READ | PROT_EXEC, MAP_PRIVATE, 3, 0)));
EXPECT_EQ(31337, p());
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
ASSERT_SYS(0, 0, close(3));
ASSERT_SYS(0, 0, munmap(p, n));
}
TEST(mprotect, testFileMap_canChangeToExecWhileOpenInRdwrMode) {
int (*p)(void);
size_t n = sizeof(kRet31337);
ASSERT_SYS(0, 3, open("return31337", O_CREAT | O_TRUNC | O_RDWR, 0755));
ASSERT_SYS(0, n, write(3, kRet31337, n));
EXPECT_NE(MAP_FAILED,
(p = mmap(NULL, n, PROT_READ | PROT_WRITE, MAP_PRIVATE, 3, 0)));
EXPECT_NE(-1, mprotect(p, n, PROT_READ | PROT_EXEC));
EXPECT_EQ(31337, p());
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
ASSERT_SYS(0, 0, close(3));
ASSERT_SYS(0, 0, munmap(p, n));
}
TEST(mprotect, testBadProt_failsEinval) {
volatile char *p = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
EXPECT_EQ(-1, mprotect(p, 9999, -1));
EXPECT_EQ(EINVAL, errno);
}
TEST(mprotect, testZeroSize_doesNothing) {
volatile char *p = gc(memalign(getauxval(AT_PAGESZ), getauxval(AT_PAGESZ)));
EXPECT_NE(-1, mprotect(p, 0, PROT_READ));
p[0] = 1;
EXPECT_FALSE(gotsegv);
EXPECT_FALSE(gotbusted);
}