freebsd-skq/sbin/casperd/zygote.c
oshogbo cf66982b37 Approved, oprócz użycie RESTORE_ERRNO() do ustawiania errno.
Change the nvlist_recv() function to take additional argument that
specifies flags expected on the received nvlist. Receiving a nvlist with
different set of flags than the ones we expect might lead to undefined
behaviour, which might be potentially dangerous.

Update consumers of this and related functions and update the tests.

Approved by:	pjd (mentor)

Update man page for nvlist_unpack, nvlist_recv, nvlist_xfer, cap_recv_nvlist
and cap_xfer_nvlist.

Reviewed by:	AllanJude
Approved by:	pjd (mentor)
2015-05-02 17:45:52 +00:00

230 lines
5.3 KiB
C

/*-
* Copyright (c) 2012 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Pawel Jakub Dawidek under sponsorship from
* the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/capsicum.h>
#include <sys/procdesc.h>
#include <sys/socket.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <paths.h>
#include <stdbool.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <libcapsicum.h>
#include <libcapsicum_impl.h>
#include <nv.h>
#include <pjdlog.h>
#include "zygote.h"
/* Zygote info. */
static int zygote_sock = -1;
static void
stdnull(void)
{
int fd;
fd = open(_PATH_DEVNULL, O_RDWR);
if (fd == -1)
errx(1, "Unable to open %s", _PATH_DEVNULL);
if (setsid() == -1)
errx(1, "Unable to detach from session");
if (dup2(fd, STDIN_FILENO) == -1)
errx(1, "Unable to cover stdin");
if (dup2(fd, STDOUT_FILENO) == -1)
errx(1, "Unable to cover stdout");
if (dup2(fd, STDERR_FILENO) == -1)
errx(1, "Unable to cover stderr");
close(fd);
}
int
zygote_clone(zygote_func_t *func, int flags, int *chanfdp, int *procfdp)
{
nvlist_t *nvl;
int error;
if (zygote_sock == -1) {
/* Zygote didn't start. */
errno = ENXIO;
return (-1);
}
nvl = nvlist_create(0);
nvlist_add_number(nvl, "func", (uint64_t)(uintptr_t)func);
nvlist_add_number(nvl, "flags", (uint64_t)flags);
nvl = nvlist_xfer(zygote_sock, nvl, 0);
if (nvl == NULL)
return (-1);
if (nvlist_exists_number(nvl, "error")) {
error = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
errno = error;
return (-1);
}
*chanfdp = nvlist_take_descriptor(nvl, "chanfd");
*procfdp = nvlist_take_descriptor(nvl, "procfd");
nvlist_destroy(nvl);
return (0);
}
/*
* This function creates sandboxes on-demand whoever has access to it via
* 'sock' socket. Function sends two descriptors to the caller: process
* descriptor of the sandbox and socket pair descriptor for communication
* between sandbox and its owner.
*/
static void
zygote_main(int sock)
{
int error, fd, flags, procfd;
int chanfd[2];
nvlist_t *nvlin, *nvlout;
zygote_func_t *func;
pid_t pid;
assert(sock > STDERR_FILENO);
setproctitle("zygote");
if (pjdlog_mode_get() != PJDLOG_MODE_STD)
stdnull();
for (fd = STDERR_FILENO + 1; fd < sock; fd++)
close(fd);
closefrom(sock + 1);
for (;;) {
nvlin = nvlist_recv(sock, 0);
if (nvlin == NULL) {
if (errno == ENOTCONN) {
/* Casperd exited. */
exit(0);
}
continue;
}
func = (zygote_func_t *)(uintptr_t)nvlist_get_number(nvlin,
"func");
flags = (int)nvlist_get_number(nvlin, "flags");
nvlist_destroy(nvlin);
/*
* Someone is requesting a new process, create one.
*/
procfd = -1;
chanfd[0] = -1;
chanfd[1] = -1;
error = 0;
if (socketpair(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0,
chanfd) == -1) {
error = errno;
goto send;
}
pid = pdfork(&procfd, 0);
switch (pid) {
case -1:
/* Failure. */
error = errno;
break;
case 0:
/* Child. */
close(sock);
close(chanfd[0]);
func(chanfd[1]);
/* NOTREACHED */
exit(1);
default:
/* Parent. */
close(chanfd[1]);
break;
}
send:
nvlout = nvlist_create(0);
if (error != 0) {
nvlist_add_number(nvlout, "error", (uint64_t)error);
if (chanfd[0] >= 0)
close(chanfd[0]);
if (procfd >= 0)
close(procfd);
} else {
nvlist_move_descriptor(nvlout, "chanfd", chanfd[0]);
nvlist_move_descriptor(nvlout, "procfd", procfd);
}
(void)nvlist_send(sock, nvlout);
nvlist_destroy(nvlout);
}
/* NOTREACHED */
}
int
zygote_init(void)
{
int serrno, sp[2];
pid_t pid;
if (socketpair(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0, sp) == -1)
return (-1);
pid = fork();
switch (pid) {
case -1:
/* Failure. */
serrno = errno;
close(sp[0]);
close(sp[1]);
errno = serrno;
return (-1);
case 0:
/* Child. */
close(sp[0]);
zygote_main(sp[1]);
/* NOTREACHED */
abort();
default:
/* Parent. */
zygote_sock = sp[0];
close(sp[1]);
return (0);
}
/* NOTREACHED */
}