freebsd-dev/sbin/bectl/bectl_jail.c
Kyle Evans cd816834d4 bectl(8): Allow running a custom command in the 'jail' subcommand
Instead of always running /bin/sh, allow the user to specify the command
to run. The jail is not removed when the command finishes. Meaning,
`bectl unjail` will still need to be run.

For example:

```
bectl jail newBE pkg upgrade
bectl ujail newBE
```

Submitted by:	Shawn Webb
Obtained from:	HardenedBSD (8b451014ab)
2018-08-18 01:12:44 +00:00

394 lines
8.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org>
*
* 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 AUTHOR ``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 AUTHOR 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/param.h>
#include <sys/jail.h>
#include <sys/mount.h>
#include <err.h>
#include <jail.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <be.h>
#include "bectl.h"
static void jailparam_grow(void);
static void jailparam_add(const char *name, const char *val);
static int jailparam_del(const char *name);
static bool jailparam_addarg(char *arg);
static int jailparam_delarg(char *arg);
static int bectl_search_jail_paths(const char *mnt);
static int bectl_locate_jail(const char *ident);
/* We'll start with 8 parameters initially and grow as needed. */
#define INIT_PARAMCOUNT 8
static struct jailparam *jp;
static int jpcnt;
static int jpused;
static char mnt_loc[BE_MAXPATHLEN];
static void
jailparam_grow(void)
{
jpcnt *= 2;
jp = realloc(jp, jpcnt * sizeof(*jp));
if (jp == NULL)
err(2, "realloc");
}
static void
jailparam_add(const char *name, const char *val)
{
int i;
for (i = 0; i < jpused; ++i) {
if (strcmp(name, jp[i].jp_name) == 0)
break;
}
if (i < jpused)
jailparam_free(&jp[i], 1);
else if (jpused == jpcnt)
/* The next slot isn't allocated yet */
jailparam_grow();
if (jailparam_init(&jp[i], name) != 0)
return;
if (jailparam_import(&jp[i], val) != 0)
return;
++jpused;
}
static int
jailparam_del(const char *name)
{
int i;
char *val;
for (i = 0; i < jpused; ++i) {
if (strcmp(name, jp[i].jp_name) == 0)
break;
}
if (i == jpused)
return (ENOENT);
for (; i < jpused - 1; ++i) {
val = jailparam_export(&jp[i + 1]);
jailparam_free(&jp[i], 1);
/*
* Given the context, the following will really only fail if
* they can't allocate the copy of the name or value.
*/
if (jailparam_init(&jp[i], jp[i + 1].jp_name) != 0) {
free(val);
return (ENOMEM);
}
if (jailparam_import(&jp[i], val) != 0) {
jailparam_free(&jp[i], 1);
free(val);
return (ENOMEM);
}
free(val);
}
jailparam_free(&jp[i], 1);
--jpused;
return (0);
}
static bool
jailparam_addarg(char *arg)
{
char *name, *val;
if (arg == NULL)
return (false);
name = arg;
if ((val = strchr(arg, '=')) == NULL) {
fprintf(stderr, "bectl jail: malformed jail option '%s'\n",
arg);
return (false);
}
*val++ = '\0';
if (strcmp(name, "path") == 0) {
if (strlen(val) >= BE_MAXPATHLEN) {
fprintf(stderr,
"bectl jail: skipping too long path assignment '%s' (max length = %d)\n",
val, BE_MAXPATHLEN);
return (false);
}
strlcpy(mnt_loc, val, sizeof(mnt_loc));
}
jailparam_add(name, val);
return (true);
}
static int
jailparam_delarg(char *arg)
{
char *name, *val;
if (arg == NULL)
return (EINVAL);
name = arg;
if ((val = strchr(name, '=')) != NULL)
*val++ = '\0';
if (strcmp(name, "path") == 0)
*mnt_loc = '\0';
return (jailparam_del(name));
}
int
bectl_cmd_jail(int argc, char *argv[])
{
char *bootenv, *mountpoint;
int jflags, jid, opt, ret;
bool default_hostname, default_name, interactive;
default_hostname = default_name = interactive = true;
jpcnt = INIT_PARAMCOUNT;
jp = malloc(jpcnt * sizeof(*jp));
if (jp == NULL)
err(2, "malloc");
jailparam_add("persist", "true");
jailparam_add("allow.mount", "true");
jailparam_add("allow.mount.devfs", "true");
jailparam_add("enforce_statfs", "1");
while ((opt = getopt(argc, argv, "bo:u:")) != -1) {
switch (opt) {
case 'b':
interactive = false;
break;
case 'o':
if (jailparam_addarg(optarg)) {
/*
* optarg has been modified to null terminate
* at the assignment operator.
*/
if (strcmp(optarg, "name") == 0)
default_name = false;
if (strcmp(optarg, "host.hostname") == 0)
default_hostname = false;
}
break;
case 'u':
if ((ret = jailparam_delarg(optarg)) == 0) {
if (strcmp(optarg, "name") == 0)
default_name = true;
if (strcmp(optarg, "host.hostname") == 0)
default_hostname = true;
} else if (ret != ENOENT) {
fprintf(stderr,
"bectl jail: error unsetting \"%s\"\n",
optarg);
return (ret);
}
break;
default:
fprintf(stderr, "bectl jail: unknown option '-%c'\n",
optopt);
return (usage(false));
}
}
argc -= optind;
argv += optind;
/* struct jail be_jail = { 0 }; */
if (argc < 1) {
fprintf(stderr, "bectl jail: missing boot environment name\n");
return (usage(false));
}
bootenv = argv[0];
/*
* XXX TODO: if its already mounted, perhaps there should be a flag to
* indicate its okay to proceed??
*/
if (*mnt_loc == '\0')
mountpoint = NULL;
else
mountpoint = mnt_loc;
if (be_mount(be, bootenv, mountpoint, 0, mnt_loc) != BE_ERR_SUCCESS) {
fprintf(stderr, "could not mount bootenv\n");
return (1);
}
if (default_name)
jailparam_add("name", bootenv);
if (default_hostname)
jailparam_add("host.hostname", bootenv);
jflags = JAIL_CREATE;
if (interactive)
jflags |= JAIL_ATTACH;
/*
* This is our indicator that path was not set by the user, so we'll use
* the path that libbe generated for us.
*/
if (mountpoint == NULL)
jailparam_add("path", mnt_loc);
jid = jailparam_set(jp, jpused, jflags);
if (jid == -1) {
fprintf(stderr, "unable to create jail. error: %d\n", errno);
return (1);
}
jailparam_free(jp, jpused);
free(jp);
if (interactive) {
/* We're attached within the jail... good bye! */
chdir("/");
if (argc > 1)
execve(argv[1], &argv[1], NULL);
else
execl("/bin/sh", "/bin/sh", NULL);
return (1);
}
return (0);
}
static int
bectl_search_jail_paths(const char *mnt)
{
char jailpath[MAXPATHLEN];
int jid;
jid = 0;
(void)mnt;
while ((jid = jail_getv(0, "lastjid", &jid, "path", &jailpath,
NULL)) != -1) {
if (strcmp(jailpath, mnt) == 0)
return (jid);
}
return (-1);
}
/*
* Locate a jail based on an arbitrary identifier. This may be either a name,
* a jid, or a BE name. Returns the jid or -1 on failure.
*/
static int
bectl_locate_jail(const char *ident)
{
nvlist_t *belist, *props;
char *mnt;
int jid;
/* Try the easy-match first */
jid = jail_getid(ident);
if (jid != -1)
return (jid);
/* Attempt to try it as a BE name, first */
if (be_prop_list_alloc(&belist) != 0)
return (-1);
if (be_get_bootenv_props(be, belist) != 0)
return (-1);
if (nvlist_lookup_nvlist(belist, ident, &props) == 0) {
/* We'll attempt to resolve the jid by way of mountpoint */
if (nvlist_lookup_string(props, "mountpoint", &mnt) == 0) {
jid = bectl_search_jail_paths(mnt);
be_prop_list_free(belist);
return (jid);
}
be_prop_list_free(belist);
}
return (-1);
}
int
bectl_cmd_unjail(int argc, char *argv[])
{
char path[MAXPATHLEN];
char *cmd, *name, *target;
int jid;
/* Store alias used */
cmd = argv[0];
if (argc != 2) {
fprintf(stderr, "bectl %s: wrong number of arguments\n", cmd);
return (usage(false));
}
target = argv[1];
/* Locate the jail */
if ((jid = bectl_locate_jail(target)) == -1) {
fprintf(stderr, "bectl %s: failed to locate BE by '%s'\n", cmd,
target);
return (1);
}
bzero(&path, MAXPATHLEN);
name = jail_getname(jid);
if (jail_getv(0, "name", name, "path", path, NULL) != jid) {
free(name);
fprintf(stderr,
"bectl %s: failed to get path for jail requested by '%s'\n",
cmd, target);
return (1);
}
free(name);
if (be_mounted_at(be, path, NULL) != 0) {
fprintf(stderr, "bectl %s: jail requested by '%s' not a BE\n",
cmd, target);
return (1);
}
jail_remove(jid);
unmount(path, 0);
return (0);
}