mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-12 09:17:53 +00:00
5a132f9652
It's now possible to pass the `-S` or `-SS` flags to sandbox redbean worker proecsses after they've been forked. The first `-S` flag is intended to be a permissive builtin policy that limits system calls to only that which the various parts of redbean serving need. The second `-SS` flag is intended to be more restrictive, preventing things like the Lua extensions you download off the web from using the HTTP client or sockets APIs. In upcoming changes you'll be able to implement your own Berkeley Packet Filter sandbox programs and load them via Lua.
98 lines
4.6 KiB
C
98 lines
4.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/calls/struct/iovec.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/sock/internal.h"
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#include "libc/sock/sock.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Sends a message on a socket.
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*
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* @param fd is the file descriptor returned by socket()
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* @param msg is a pointer to a struct msghdr containing all the required
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* parameters (the destination address, buffers, ...)
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* @param flags MSG_OOB, MSG_DONTROUTE, MSG_PARTIAL, MSG_NOSIGNAL, etc.
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* @return number of bytes transmitted, or -1 w/ errno
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* @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
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* EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
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* @asyncsignalsafe
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* @restartable (unless SO_RCVTIMEO)
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*/
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ssize_t sendmsg(int fd, const struct msghdr *msg, int flags) {
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int64_t rc;
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char addr2[128];
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struct msghdr msg2;
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if (IsAsan() && !__asan_is_valid_msghdr(msg)) {
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rc = efault();
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} else if (!IsWindows()) {
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if (IsBsd() && msg->msg_name) {
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/* An optional address is provided, convert it to the BSD form */
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if (msg->msg_namelen <= sizeof(addr2)) {
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memcpy(&addr2[0], msg->msg_name, msg->msg_namelen);
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sockaddr2bsd(&addr2[0]);
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/* Copy all of msg (except for msg_name) into the new ephemeral local */
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memcpy(&msg2, msg, sizeof(msg2));
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msg2.msg_name = &addr2[0];
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rc = sys_sendmsg(fd, &msg2, flags);
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} else {
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rc = einval();
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}
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}
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/* else do the syscall */
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rc = sys_sendmsg(fd, msg, flags);
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} else if (__isfdopen(fd)) {
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if (msg->msg_control) {
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rc = einval(); /* control msg not supported */
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} else if (__isfdkind(fd, kFdSocket)) {
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rc = sys_sendto_nt(fd, msg->msg_iov, msg->msg_iovlen, flags,
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msg->msg_name, msg->msg_namelen);
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} else if (__isfdkind(fd, kFdFile)) {
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rc = sys_write_nt(fd, msg->msg_iov, msg->msg_iovlen, -1);
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} else {
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rc = enotsock();
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}
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} else {
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rc = ebadf();
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}
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#if defined(SYSDEBUG) && _DATATRACE
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if (__strace > 0) {
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if (!msg || (rc == -1 && errno == EFAULT)) {
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DATATRACE("sendmsg(%d, %p, %#x) → %'ld% m", fd, msg, flags, rc);
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} else {
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kprintf(STRACE_PROLOGUE "sendmsg(%d, {");
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if (msg->msg_namelen)
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kprintf(".name=%#.*hhs, ", msg->msg_namelen, msg->msg_name);
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if (msg->msg_controllen)
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kprintf(".control=%#.*hhs, ", msg->msg_controllen, msg->msg_control);
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if (msg->msg_flags) kprintf(".flags=%#x, ", msg->msg_flags);
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kprintf(".iov=", fd);
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__strace_iov(msg->msg_iov, msg->msg_iovlen, rc != -1 ? rc : 0);
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kprintf("}, %#x) → %'ld% m%n", flags, rc);
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}
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}
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#endif
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return rc;
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}
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