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Add pledge.com for launching commands in a sandbox

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This commit is contained in:
Justine Tunney 2022-07-13 03:08:16 -07:00
parent 12d9f7ade6
commit 1d490fcb94
8 changed files with 308 additions and 297 deletions
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217
tool/build/jail.c
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@ -1,217 +0,0 @@
/*-*- 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/struct/filter.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/struct/sigset.h"
#include "libc/calls/struct/user_regs_struct.h"
#include "libc/calls/ucontext.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/kprintf.h"
#include "libc/log/check.h"
#include "libc/log/log.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/pr.h"
#include "libc/sysv/consts/ptrace.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "tool/net/sandbox.h"
#define __WALL 0x40000000
static const struct sock_filter kSandboxFilter[] = {
_SECCOMP_MACHINE(AUDIT_ARCH_X86_64), //
_SECCOMP_LOAD_SYSCALL_NR(), //
_SECCOMP_ALLOW_SYSCALL(0x000), // read
_SECCOMP_ALLOW_SYSCALL(0x001), // write
_SECCOMP_ALLOW_SYSCALL(0x013), // readv
_SECCOMP_ALLOW_SYSCALL(0x014), // writev
_SECCOMP_ALLOW_SYSCALL(0x005), // fstat
_SECCOMP_ALLOW_SYSCALL(0x007), // poll
_SECCOMP_ALLOW_SYSCALL(0x008), // lseek
_SECCOMP_ALLOW_SYSCALL(0x009), // mmap
_SECCOMP_ALLOW_SYSCALL(0x00b), // munmap
_SECCOMP_ALLOW_SYSCALL(0x04f), // getcwd
_SECCOMP_ALLOW_SYSCALL(0x003), // close
_SECCOMP_ALLOW_SYSCALL(0x010), // ioctl todo
_SECCOMP_ALLOW_SYSCALL(0x016), // pipe
_SECCOMP_ALLOW_SYSCALL(0x125), // pipe2
_SECCOMP_ALLOW_SYSCALL(0x035), // socketpair
_SECCOMP_ALLOW_SYSCALL(0x020), // dup
_SECCOMP_ALLOW_SYSCALL(0x021), // dup2
_SECCOMP_ALLOW_SYSCALL(0x124), // dup3
_SECCOMP_ALLOW_SYSCALL(0x039), // fork
_SECCOMP_ALLOW_SYSCALL(0x03a), // vfork
_SECCOMP_ALLOW_SYSCALL(0x011), // pread
_SECCOMP_ALLOW_SYSCALL(0x012), // pwrite
_SECCOMP_ALLOW_SYSCALL(0x127), // preadv
_SECCOMP_ALLOW_SYSCALL(0x128), // pwritev
_SECCOMP_ALLOW_SYSCALL(0x0d9), // getdents
_SECCOMP_ALLOW_SYSCALL(0x027), // getpid
_SECCOMP_ALLOW_SYSCALL(0x066), // getuid
_SECCOMP_ALLOW_SYSCALL(0x068), // getgid
_SECCOMP_ALLOW_SYSCALL(0x06e), // getppid
_SECCOMP_ALLOW_SYSCALL(0x06f), // getpgrp
_SECCOMP_ALLOW_SYSCALL(0x07c), // getsid
_SECCOMP_ALLOW_SYSCALL(0x06b), // geteuid
_SECCOMP_ALLOW_SYSCALL(0x06c), // getegid
_SECCOMP_ALLOW_SYSCALL(0x061), // getrlimit
_SECCOMP_ALLOW_SYSCALL(0x028), // sendfile
_SECCOMP_ALLOW_SYSCALL(0x02d), // recvfrom
_SECCOMP_ALLOW_SYSCALL(0x033), // getsockname
_SECCOMP_ALLOW_SYSCALL(0x034), // getpeername
_SECCOMP_ALLOW_SYSCALL(0x00f), // rt_sigreturn
_SECCOMP_ALLOW_SYSCALL(0x082), // rt_sigsuspend
_SECCOMP_ALLOW_SYSCALL(0x0e4), // clock_gettime
_SECCOMP_ALLOW_SYSCALL(0x060), // gettimeofday
_SECCOMP_ALLOW_SYSCALL(0x03f), // uname
_SECCOMP_ALLOW_SYSCALL(0x03c), // exit
_SECCOMP_ALLOW_SYSCALL(0x0e7), // exit_group
_SECCOMP_TRACE_SYSCALL(0x03e, 0), // kill
_SECCOMP_TRACE_SYSCALL(0x101, 0), // openat
_SECCOMP_TRACE_SYSCALL(0x106, 0), // newfstatat
_SECCOMP_TRACE_SYSCALL(0x029, 0), // socket
_SECCOMP_TRACE_SYSCALL(0x031, 0), // bind
_SECCOMP_TRACE_SYSCALL(0x02a, 0), // connect
_SECCOMP_TRACE_SYSCALL(0x02c, 0), // sendto
_SECCOMP_TRACE_SYSCALL(0x036, 0), // setsockopt
_SECCOMP_TRACE_SYSCALL(0x048, 0), // fcntl
_SECCOMP_TRACE_SYSCALL(0x03b, 0), // execve
_SECCOMP_TRACE_SYSCALL(0x102, 0), // mkdirat
_SECCOMP_TRACE_SYSCALL(0x104, 0), // chownat
_SECCOMP_TRACE_SYSCALL(0x107, 0), // unlinkat
_SECCOMP_TRACE_SYSCALL(0x108, 0), // renameat
_SECCOMP_TRACE_SYSCALL(0x109, 0), // linkat
_SECCOMP_TRACE_SYSCALL(0x10a, 0), // symlinkat
_SECCOMP_TRACE_SYSCALL(0x10b, 0), // readlinkat
_SECCOMP_TRACE_SYSCALL(0x10c, 0), // fchmodat
_SECCOMP_TRACE_SYSCALL(0x10d, 0), // faccessat
_SECCOMP_TRACE_SYSCALL(0x0eb, 0), // utimes
_SECCOMP_TRACE_SYSCALL(0x105, 0), // futimesat
_SECCOMP_TRACE_SYSCALL(0x118, 0), // utimensat
_SECCOMP_LOG_AND_RETURN_ERRNO(1), // EPERM
};
static const struct sock_fprog kSandbox = {
.len = ARRAYLEN(kSandboxFilter),
.filter = kSandboxFilter,
};
void OnSys(int sig, siginfo_t *si, ucontext_t *ctx) {
kprintf("Got SIGSYS%n");
}
int main(int argc, char *argv[]) {
sigset_t mask, origmask;
struct user_regs_struct regs;
int child, evpid, signal, wstatus;
if (!IsLinux()) {
kprintf("error: %s is only supported on linux right now%n", argv[0]);
return 1;
}
if (argc < 2) {
kprintf("Usage: %s PROGRAM [ARGS...]%n", argv[0]);
return 1;
}
/* ShowCrashReports(); */
sigaction(SIGINT, &(struct sigaction){.sa_handler = SIG_IGN}, 0);
sigaction(SIGQUIT, &(struct sigaction){.sa_handler = SIG_IGN}, 0);
sigaction(SIGSYS,
&((struct sigaction){
.sa_sigaction = OnSys,
.sa_flags = SA_SIGINFO,
}),
0);
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigprocmask(SIG_BLOCK, &mask, &origmask);
CHECK_NE(-1, (child = fork()));
if (!child) {
sigaction(SIGINT, &(struct sigaction){.sa_handler = SIG_DFL}, 0);
sigaction(SIGQUIT, &(struct sigaction){.sa_handler = SIG_DFL}, 0);
kprintf("CHILD ptrace(PTRACE_TRACEME)%n");
if (ptrace(PTRACE_TRACEME) == -1) {
kprintf("CHILD ptrace(PTRACE_TRACEME) failed %m%n");
_Exit(124);
}
kprintf("CHILD prctl(PR_SET_NO_NEW_PRIVS)%n");
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1) {
kprintf("CHILD prctl(PR_SET_NO_NEW_PRIVS) failed %m%n");
_Exit(125);
}
kprintf("CHILD prctl(PR_SET_SECCOMP)%n");
if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &kSandbox) == -1) {
kprintf("CHILD prctl(PR_SET_SECCOMP) failed %m%n");
_Exit(126);
}
kprintf("CHILD sigsuspend()%n");
if (sigsuspend(0) == -1) {
kprintf("CHILD sigsuspend() failed %m%n");
}
sigaction(SIGSYS, &(struct sigaction){.sa_handler = SIG_DFL}, 0);
sigprocmask(SIG_SETMASK, &origmask, 0);
execv(argv[1], argv + 1);
kprintf("CHILD execve(%#s) failed %m%n", argv[1]);
_Exit(127);
}
// wait for ptrace(PTRACE_TRACEME) to be called
kprintf("PARENT waitpid(child, &wstatus)%n");
CHECK_EQ(child, waitpid(child, &wstatus, 0));
// configure linux process tracing
kprintf("PARENT ptrace(PTRACE_SETOPTIONS)%n");
CHECK_NE(-1, ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESECCOMP));
// continue child process
kprintf("PARENT ptrace(PTRACE_CONT)%n");
CHECK_NE(-1, ptrace(PTRACE_CONT, child, 0, 0));
kprintf("PARENT kill(child, SIGSYS)%n");
kill(child, SIGSYS);
for (;;) {
kprintf("PARENT waitpid()%n");
CHECK_NE(-1, (evpid = waitpid(-1, &wstatus, __WALL)));
if (WIFSTOPPED(wstatus)) {
signal = (wstatus >> 8) & 0xffff;
if (signal == SIGTRAP | PTRACE_EVENT_SECCOMP) {
// CHECK_NE(-1, ptrace(PTRACE_GETEVENTMSG, evpid, 0, &msg));
CHECK_NE(-1, ptrace(PTRACE_GETREGS, evpid, 0, regs));
regs.rax = -EPERM;
CHECK_NE(-1, ptrace(PTRACE_GETREGS, evpid, 0, regs));
ptrace(PTRACE_CONT, evpid, 0, 0);
} else {
ptrace(PTRACE_CONT, evpid, 0, signal & 127);
}
} else if (WIFEXITED(wstatus)) {
exit(WEXITSTATUS(wstatus));
} else {
exit(128 + WTERMSIG(wstatus));
}
}
return 0;
}

136
tool/build/pledge.c Normal file
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@ -0,0 +1,136 @@
/*-*- 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/errno.h"
#include "libc/fmt/conv.h"
#include "libc/intrin/kprintf.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "third_party/getopt/getopt.h"
// options used: hpugc
// letters not used: ABCDEFGHIJKLMNOPQRSTUVWXYZabdefijklmnoqrstvwxyz
// digits not used: 0123456789
// puncts not used: !"#$%&'()*+,-./;<=>@[\]^_`{|}~
// letters duplicated: none
#define GETOPTS "hp:u:g:c:"
#define USAGE \
"\
usage: pledge.com [-h] PROG ARGS...\n\
-h show help\n\
-g GID call setgid()\n\
-u UID call setuid()\n\
-c PATH call chroot()\n\
-p PLEDGE may contain any of following separated by spaces\n\
- stdio: allow stdio and benign system calls\n\
- rpath: read-only path ops\n\
- wpath: write path ops\n\
- cpath: create path ops\n\
- dpath: create special files\n\
- flock: file locks\n\
- tty: terminal ioctls\n\
- recvfd: allow SCM_RIGHTS\n\
- fattr: allow changing some struct stat bits\n\
- inet: allow IPv4 and IPv6\n\
- unix: allow local sockets\n\
- dns: allow dns\n\
- proc: allow fork, clone and friends\n\
- thread: allow clone\n\
- id: allow setuid and friends\n\
- exec: allow executing ape binaries\n\
"
int g_gflag;
int g_uflag;
int g_hflag;
const char *g_pflag;
const char *g_cflag;
static void GetOpts(int argc, char *argv[]) {
int opt;
g_pflag = "";
while ((opt = getopt(argc, argv, GETOPTS)) != -1) {
switch (opt) {
case 'p':
g_pflag = optarg;
break;
case 'c':
g_cflag = optarg;
break;
case 'g':
g_gflag = atoi(optarg);
break;
case 'u':
g_uflag = atoi(optarg);
break;
case 'h':
case '?':
write(1, USAGE, sizeof(USAGE) - 1);
exit(0);
default:
write(2, USAGE, sizeof(USAGE) - 1);
exit(64);
}
}
}
const char *prog;
char pledges[1024];
char pathbuf[PATH_MAX];
int main(int argc, char *argv[]) {
GetOpts(argc, argv);
if (optind == argc) {
kprintf("error: too few args\n", g_pflag);
write(2, USAGE, sizeof(USAGE) - 1);
exit(64);
}
if (g_cflag) {
if (chroot(g_cflag) == -1) {
kprintf("error: chroot(%`'s) failed: %s\n", g_cflag, strerror(errno));
return 1;
}
}
if (!(prog = commandv(argv[optind], pathbuf, sizeof(pathbuf)))) {
kprintf("error: command not found: %s\n", argv[optind]);
return 2;
}
if (g_gflag) {
if (setgid(g_gflag) == -1) {
kprintf("error: setgid(%d) failed: %s\n", g_gflag, strerror(errno));
return 3;
}
}
if (g_uflag) {
if (setuid(g_uflag) == -1) {
kprintf("error: setuid(%d) failed: %s\n", g_uflag, strerror(errno));
return 4;
}
}
ksnprintf(pledges, sizeof(pledges), "%s execnative", g_pflag);
if (pledge(pledges, 0) == -1) {
kprintf("error: pledge(%`'s) failed: %s\n", pledges, strerror(errno));
return 5;
}
execv(prog, argv + optind);
kprintf("error: execve(%`'s) failed: %s\n", prog, strerror(errno));
return 127;
}

2
tool/net/help.txt
View file

@ -765,7 +765,7 @@ FUNCTIONS
If the raw length of a table is reported as zero, then we
check for the magic element `[0]=false`. If it's present, then
your table will be serialized as empty array `[]`. That entry
your table will be serialized as empty array `[]`. An entry is
inserted by DecodeJson() automatically, only when encountering
empty arrays, and it's necessary in order to make empty arrays
round-trip. If raw length is zero and `[0]=false` is absent,