cosmopolitan/test/libc/calls/unveil_test.c
Justine Tunney 6f7d0cb1c3
Pay off more technical debt
This makes breaking changes to add underscores to many non-standard
function names provided by the c library. MODE=tiny is now tinier and
we now use smaller locks that are better for tiny apps in this mode.
Some headers have been renamed to be in the same folder as the build
package, so it'll be easier to know which build dependency is needed.
Certain old misguided interfaces have been removed. Intel intrinsics
headers are now listed in libc/isystem (but not in the amalgamation)
to help further improve open source compatibility. Header complexity
has also been reduced. Lastly, more shell scripts are now available.
2022-09-12 23:36:56 -07:00

400 lines
14 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 2022 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/landlock.h"
#include "libc/calls/struct/dirent.h"
#include "libc/calls/struct/stat.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/kprintf.h"
#include "libc/mem/gc.h"
#include "libc/calls/copyfd.internal.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/sock.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/msync.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/s.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/sock.h"
#include "libc/testlib/subprocess.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/spawn.h"
#include "libc/x/x.h"
#include "libc/x/xasprintf.h"
STATIC_YOINK("zip_uri_support");
#define EACCES_OR_ENOENT (IsOpenbsd() ? ENOENT : EACCES)
char testlib_enable_tmp_setup_teardown;
struct stat st;
static bool SupportsLandlock(void) {
int e = errno;
bool r = landlock_create_ruleset(0, 0, LANDLOCK_CREATE_RULESET_VERSION) >= 0;
errno = e;
return r;
}
void SetUpOnce(void) {
__enable_threads();
if (!(IsLinux() && SupportsLandlock()) && !IsOpenbsd()) exit(0);
}
void SetUp(void) {
// make sure zipos maps executable into memory early
ASSERT_SYS(0, 0, stat("/zip/life.elf", &st));
}
int extract(const char *from, const char *to, int mode) {
int fdin, fdout;
if ((fdin = open(from, O_RDONLY)) == -1) return -1;
if ((fdout = creat(to, mode)) == -1) {
close(fdin);
return -1;
}
if (_copyfd(fdin, fdout, -1) == -1) {
close(fdout);
close(fdin);
return -1;
}
return close(fdout) | close(fdin);
}
TEST(unveil, api_differences) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("foo", 0755));
ASSERT_SYS(0, 0, unveil("foo", "r"));
if (IsOpenbsd()) {
// openbsd imposes restrictions immediately
ASSERT_SYS(ENOENT, -1, open("/", O_RDONLY | O_DIRECTORY));
} else {
// restrictions on linux don't go into effect until unveil(0,0)
ASSERT_SYS(0, 3, open(".", O_RDONLY | O_DIRECTORY));
ASSERT_SYS(0, 0, close(3));
}
ASSERT_SYS(0, 0, unveil(0, 0));
// error numbers are inconsistent
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("/", O_RDONLY | O_DIRECTORY));
// wut
if (IsLinux()) {
ASSERT_SYS(0, 3, open("/", O_PATH)); // wut
ASSERT_SYS(0, 0, stat("/", &st)); // wut
}
EXITS(0);
}
TEST(unveil, rx_readOnlyPreexistingExecutable_worksFine) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("folder", 0755));
ASSERT_SYS(0, 0, extract("/zip/life.elf", "folder/life.elf", 0755));
ASSERT_SYS(0, 0, unveil("folder", "rx"));
ASSERT_SYS(0, 0, unveil(0, 0));
SPAWN(fork);
execl("folder/life.elf", "folder/life.elf", 0);
kprintf("execve failed! %s\n", strerror(errno));
_Exit(127);
EXITS(42);
EXITS(0);
}
TEST(unveil, r_noExecutePreexistingExecutable_raisesEacces) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("folder", 0755));
ASSERT_SYS(0, 0, extract("/zip/life.elf", "folder/life.elf", 0755));
ASSERT_SYS(0, 0, unveil("folder", "r"));
ASSERT_SYS(0, 0, unveil(0, 0));
SPAWN(fork);
ASSERT_SYS(EACCES, -1, execl("folder/life.elf", "folder/life.elf", 0));
EXITS(0);
EXITS(0);
}
TEST(unveil, canBeUsedAgainAfterVfork) {
ASSERT_SYS(0, 0, touch("bad", 0644));
ASSERT_SYS(0, 0, touch("good", 0644));
SPAWN(fork);
SPAWN(vfork);
ASSERT_SYS(0, 0, unveil("bad", "r"));
ASSERT_SYS(0, 0, unveil("good", "r"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 3, open("bad", 0));
EXITS(0);
ASSERT_SYS(0, 0, unveil("good", "r"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 3, open("good", 0));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("bad", 0));
EXITS(0);
}
TEST(unveil, rwc_createExecutableFile_isAllowedButCantBeRun) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("folder", 0755));
ASSERT_SYS(0, 0, unveil("folder", "rwc"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 0, extract("/zip/life.elf", "folder/life.elf", 0755));
SPAWN(fork);
ASSERT_SYS(0, 0, stat("folder/life.elf", &st));
ASSERT_SYS(EACCES, -1, execl("folder/life.elf", "folder/life.elf", 0));
EXITS(0);
EXITS(0);
}
TEST(unveil, rwcx_createExecutableFile_canAlsoBeRun) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("folder", 0755));
ASSERT_SYS(0, 0, unveil("folder", "rwcx"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 0, extract("/zip/life.elf", "folder/life.elf", 0755));
SPAWN(fork);
ASSERT_SYS(0, 0, stat("folder/life.elf", &st));
execl("folder/life.elf", "folder/life.elf", 0);
kprintf("execve failed! %s\n", strerror(errno));
_Exit(127);
EXITS(42);
EXITS(0);
}
TEST(unveil, dirfdHacking_doesntWork) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, touch("garden/secret.txt", 0644));
ASSERT_SYS(0, 3, open("garden", O_RDONLY | O_DIRECTORY));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(EACCES_OR_ENOENT, -1, openat(3, "secret.txt", O_RDONLY));
EXITS(0);
}
TEST(unveil, mostRestrictivePolicy) {
if (IsOpenbsd()) return; // openbsd behaves oddly; see docs
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, touch("garden/secret.txt", 0644));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("jail", O_RDONLY | O_DIRECTORY));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
EXITS(0);
}
TEST(unveil, overlappingDirectories_inconsistentBehavior) {
SPAWN(fork);
ASSERT_SYS(0, 0, makedirs("f1/f2", 0755));
ASSERT_SYS(0, 0, extract("/zip/life.elf", "f1/f2/life.elf", 0755));
ASSERT_SYS(0, 0, unveil("f1", "x"));
ASSERT_SYS(0, 0, unveil("f1/f2", "r"));
ASSERT_SYS(0, 0, unveil(0, 0));
if (IsOpenbsd()) {
// OpenBSD favors the most restrictive policy
SPAWN(fork);
ASSERT_SYS(0, 0, stat("f1/f2/life.elf", &st));
ASSERT_SYS(EACCES, -1, execl("f1/f2/life.elf", "f1/f2/life.elf", 0));
EXITS(0);
} else {
// Landlock (Linux) uses the union of policies
//
// TODO(jart): this test flakes on github actions. it reports an
// exit code of 0! find out why this is happening...
// so far it's happened to MODE=rel and MODE=tiny...
//
// SPAWN(fork);
// ASSERT_SYS(0, 0, stat("f1/f2/life.elf", &st));
// execl("f1/f2/life.elf", "f1/f2/life.elf", 0);
// kprintf("execve failed! %s\n", strerror(errno));
// _Exit(127);
// EXITS(42);
}
EXITS(0);
}
TEST(unveil, usedTwice_allowedOnLinux) {
if (IsOpenbsd()) return;
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, xbarf("jail/ok.txt", "hello", 5));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, mkdir("heaven", 0755));
ASSERT_SYS(0, 0, xbarf("heaven/verysecret.txt", "hello", 5));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil("garden", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 3, open("garden/secret.txt", O_RDONLY));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil("heaven", "rw")); // not allowed, superset of parent
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 4, open("jail/ok.txt", O_RDONLY));
ASSERT_SYS(EACCES, -1, open("garden/secret.txt", O_RDONLY));
ASSERT_SYS(EACCES, -1, open("heaven/verysecret.txt", O_RDONLY));
EXITS(0);
}
TEST(unveil, truncate_isForbiddenBySeccomp) {
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(IsOpenbsd() ? ENOENT : EPERM, -1,
truncate("garden/secret.txt", 0));
if (IsLinux()) {
ASSERT_SYS(0, 0, stat("garden/secret.txt", &st));
ASSERT_EQ(5, st.st_size);
}
EXITS(0);
}
TEST(unveil, ftruncate_isForbidden) {
if (IsOpenbsd()) return; // b/c O_PATH is a Linux thing
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 3, open("garden/secret.txt", O_PATH));
ASSERT_SYS(EBADF, -1, ftruncate(3, 0));
ASSERT_SYS(0, 0, close(3));
ASSERT_SYS(0, 0, stat("garden/secret.txt", &st));
ASSERT_EQ(5, st.st_size);
EXITS(0);
}
TEST(unveil, procfs_isForbiddenByDefault) {
if (IsOpenbsd()) return;
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(EACCES, -1, open("/proc/self/cmdline", O_RDONLY));
EXITS(0);
}
int Worker(void *arg, int tid) {
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
return 0;
}
TEST(unveil, isInheritedAcrossThreads) {
struct spawn t;
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 0, _spawn(Worker, 0, &t));
EXPECT_SYS(0, 0, _join(&t));
EXITS(0);
}
int Worker2(void *arg, int tid) {
ASSERT_SYS(0, 0, unveil("jail", "rw"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
return 0;
}
TEST(unveil, isThreadSpecificOnLinux_isProcessWideOnOpenbsd) {
struct spawn t;
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, _spawn(Worker2, 0, &t));
EXPECT_SYS(0, 0, _join(&t));
if (IsOpenbsd()) {
ASSERT_SYS(ENOENT, -1, open("garden/secret.txt", O_RDONLY));
} else {
ASSERT_SYS(0, 3, open("garden/secret.txt", O_RDONLY));
}
EXITS(0);
}
TEST(unveil, usedTwice_forbidden_worksWithPledge) {
int ws, pid;
bool *gotsome;
ASSERT_NE(-1, (gotsome = _mapshared(FRAMESIZE)));
ASSERT_NE(-1, (pid = fork()));
if (!pid) {
// install our first seccomp filter
ASSERT_SYS(0, 0, pledge("stdio rpath wpath cpath unveil", 0));
ASSERT_SYS(0, 0, mkdir("jail", 0755));
ASSERT_SYS(0, 0, mkdir("garden", 0755));
ASSERT_SYS(0, 0, xbarf("garden/secret.txt", "hello", 5));
ASSERT_SYS(0, 0, unveil("jail", "rw"));
// committing and locking causes a new bpf filter to be installed
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
// verify the second filter is working
ASSERT_SYS(EACCES_OR_ENOENT, -1, open("garden/secret.txt", O_RDONLY));
// verify the first filter is still working
*gotsome = true;
socket(AF_UNIX, SOCK_STREAM, 0);
_Exit(0);
}
ASSERT_NE(-1, wait(&ws));
ASSERT_TRUE(*gotsome);
ASSERT_TRUE(WIFSIGNALED(ws));
ASSERT_EQ(IsOpenbsd() ? SIGABRT : SIGSYS, WTERMSIG(ws));
EXPECT_SYS(0, 0, munmap(gotsome, FRAMESIZE));
}
TEST(unveil, lotsOfPaths) {
int i, n;
SPAWN(fork);
n = 100;
for (i = 0; i < n; ++i) {
ASSERT_SYS(0, 0, touch(xasprintf("%d", i), 0644));
ASSERT_SYS(0, 0, touch(xasprintf("%d-", i), 0644));
}
for (i = 0; i < n; ++i) {
ASSERT_SYS(0, 0, unveil(xasprintf("%d", i), "rw"));
}
ASSERT_SYS(0, 0, unveil(0, 0));
for (i = 0; i < n; ++i) {
ASSERT_SYS(0, 3, open(xasprintf("%d", i), O_RDONLY));
ASSERT_SYS(0, 0, close(3));
ASSERT_SYS(EACCES_OR_ENOENT, -1, open(xasprintf("%d-", i), O_RDONLY));
}
EXITS(0);
}
TEST(unveil, reparent) {
return; // need abi 2 :'(
SPAWN(fork);
ASSERT_SYS(0, 0, mkdir("x", 0755));
ASSERT_SYS(0, 0, unveil("x", "rwc"));
ASSERT_SYS(0, 0, unveil(0, 0));
ASSERT_SYS(0, 0, mkdir("x/y", 0755));
ASSERT_SYS(0, 0, touch("x/y/z", 0644));
ASSERT_SYS(0, 0, rename("x/y/z", "x/z"));
EXITS(0);
}