freebsd-dev/usr.sbin/jail/jail.c
Jamie Gritton 843c277bfa Handle kernels that don't have IPv6 by not sending an "ip6.addr"
parameter unless a (numeric) IPv6 address is given.  Even the default
binaries built with -DINET6 will work with IPv6-less kernels.  With an
eye to the future, similarly handle the possibility of an IPv4-less kernel.

Approved by:	re (kib), bz (mentor)
2009-07-31 14:30:06 +00:00

558 lines
13 KiB
C

/*-
* Copyright (c) 1999 Poul-Henning Kamp.
* Copyright (c) 2009 James Gritton
* All rights reserved.
*
* 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 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 AUTHOR 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/param.h>
#include <sys/jail.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <jail.h>
#include <login_cap.h>
#include <netdb.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static struct jailparam *params;
static char **param_values;
static int nparams;
static char *ip4_addr;
#ifdef INET6
static char *ip6_addr;
#endif
static void add_ip_addr(char **addrp, char *newaddr);
#ifdef INET6
static void add_ip_addr46(char *newaddr);
#endif
static void add_ip_addrinfo(int ai_flags, char *value);
static void quoted_print(FILE *fp, char *str);
static void set_param(const char *name, char *value);
static void usage(void);
static const char *perm_sysctl[][3] = {
{ "security.jail.set_hostname_allowed",
"allow.noset_hostname", "allow.set_hostname" },
{ "security.jail.sysvipc_allowed",
"allow.nosysvipc", "allow.sysvipc" },
{ "security.jail.allow_raw_sockets",
"allow.noraw_sockets", "allow.raw_sockets" },
{ "security.jail.chflags_allowed",
"allow.nochflags", "allow.chflags" },
{ "security.jail.mount_allowed",
"allow.nomount", "allow.mount" },
{ "security.jail.socket_unixiproute_only",
"allow.socket_af", "allow.nosocket_af" },
};
extern char **environ;
#define GET_USER_INFO do { \
pwd = getpwnam(username); \
if (pwd == NULL) { \
if (errno) \
err(1, "getpwnam: %s", username); \
else \
errx(1, "%s: no such user", username); \
} \
lcap = login_getpwclass(pwd); \
if (lcap == NULL) \
err(1, "getpwclass: %s", username); \
ngroups = ngroups_max; \
if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \
err(1, "getgrouplist: %s", username); \
} while (0)
int
main(int argc, char **argv)
{
login_cap_t *lcap = NULL;
struct passwd *pwd = NULL;
gid_t *groups;
size_t sysvallen;
int ch, cmdarg, i, jail_set_flags, jid, ngroups, sysval;
int hflag, iflag, Jflag, lflag, rflag, uflag, Uflag;
long ngroups_max;
unsigned pi;
char *jailname, *securelevel, *username, *JidFile;
char enforce_statfs[4];
static char *cleanenv;
const char *shell, *p = NULL;
FILE *fp;
hflag = iflag = Jflag = lflag = rflag = uflag = Uflag =
jail_set_flags = 0;
cmdarg = jid = -1;
jailname = securelevel = username = JidFile = cleanenv = NULL;
fp = NULL;
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
while ((ch = getopt(argc, argv, "cdhilmn:r:s:u:U:J:")) != -1) {
switch (ch) {
case 'd':
jail_set_flags |= JAIL_DYING;
break;
case 'h':
hflag = 1;
break;
case 'i':
iflag = 1;
break;
case 'J':
JidFile = optarg;
Jflag = 1;
break;
case 'n':
jailname = optarg;
break;
case 's':
securelevel = optarg;
break;
case 'u':
username = optarg;
uflag = 1;
break;
case 'U':
username = optarg;
Uflag = 1;
break;
case 'l':
lflag = 1;
break;
case 'c':
jail_set_flags |= JAIL_CREATE;
break;
case 'm':
jail_set_flags |= JAIL_UPDATE;
break;
case 'r':
jid = jail_getid(optarg);
if (jid < 0)
errx(1, "%s", jail_errmsg);
rflag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (rflag) {
if (argc > 0 || iflag || Jflag || lflag || uflag || Uflag)
usage();
if (jail_remove(jid) < 0)
err(1, "jail_remove");
exit (0);
}
if (argc == 0)
usage();
if (uflag && Uflag)
usage();
if (lflag && username == NULL)
usage();
if (uflag)
GET_USER_INFO;
if (jailname)
set_param("name", jailname);
if (securelevel)
set_param("securelevel", securelevel);
if (jail_set_flags) {
for (i = 0; i < argc; i++) {
if (!strncmp(argv[i], "command=", 8)) {
cmdarg = i;
argv[cmdarg] += 8;
jail_set_flags |= JAIL_ATTACH;
break;
}
if (hflag) {
if (!strncmp(argv[i], "ip4.addr=", 9)) {
add_ip_addr(&ip4_addr, argv[i] + 9);
break;
}
#ifdef INET6
if (!strncmp(argv[i], "ip6.addr=", 9)) {
add_ip_addr(&ip6_addr, argv[i] + 9);
break;
}
#endif
if (!strncmp(argv[i], "host.hostname=", 14))
add_ip_addrinfo(0, argv[i] + 14);
}
set_param(NULL, argv[i]);
}
} else {
if (argc < 4 || argv[0][0] != '/')
errx(1, "%s\n%s",
"no -c or -m, so this must be an old-style command.",
"But it doesn't look like one.");
set_param("path", argv[0]);
set_param("host.hostname", argv[1]);
if (hflag)
add_ip_addrinfo(0, argv[1]);
if (argv[2][0] != '\0')
#ifdef INET6
add_ip_addr46(argv[2]);
#else
add_ip_addr(&ip4_addr, argv[2]);
#endif
cmdarg = 3;
/* Emulate the defaults from security.jail.* sysctls */
sysvallen = sizeof(sysval);
if (sysctlbyname("security.jail.jailed", &sysval, &sysvallen,
NULL, 0) == 0 && sysval == 0) {
for (pi = 0; pi < sizeof(perm_sysctl) /
sizeof(perm_sysctl[0]); pi++) {
sysvallen = sizeof(sysval);
if (sysctlbyname(perm_sysctl[pi][0],
&sysval, &sysvallen, NULL, 0) == 0)
set_param(perm_sysctl[pi]
[sysval ? 2 : 1], NULL);
}
sysvallen = sizeof(sysval);
if (sysctlbyname("security.jail.enforce_statfs",
&sysval, &sysvallen, NULL, 0) == 0) {
snprintf(enforce_statfs,
sizeof(enforce_statfs), "%d", sysval);
set_param("enforce_statfs", enforce_statfs);
}
}
}
if (ip4_addr != NULL)
set_param("ip4.addr", ip4_addr);
#ifdef INET6
if (ip6_addr != NULL)
set_param("ip6.addr", ip6_addr);
#endif
if (Jflag) {
fp = fopen(JidFile, "w");
if (fp == NULL)
errx(1, "Could not create JidFile: %s", JidFile);
}
jid = jailparam_set(params, nparams,
jail_set_flags ? jail_set_flags : JAIL_CREATE | JAIL_ATTACH);
if (jid < 0)
errx(1, "%s", jail_errmsg);
if (iflag) {
printf("%d\n", jid);
fflush(stdout);
}
if (Jflag) {
if (jail_set_flags) {
fprintf(fp, "jid=%d", jid);
for (i = 0; i < nparams; i++)
if (strcmp(params[i].jp_name, "jid")) {
fprintf(fp, " %s",
(char *)params[i].jp_name);
if (param_values[i]) {
putc('=', fp);
quoted_print(fp,
param_values[i]);
}
}
fprintf(fp, "\n");
} else {
for (i = 0; i < nparams; i++)
if (!strcmp(params[i].jp_name, "path"))
break;
#ifdef INET6
fprintf(fp, "%d\t%s\t%s\t%s%s%s\t%s\n",
jid, i < nparams
? (char *)params[i].jp_value : argv[0],
argv[1], ip4_addr ? ip4_addr : "",
ip4_addr && ip4_addr[0] && ip6_addr && ip6_addr[0]
? "," : "", ip6_addr ? ip6_addr : "", argv[3]);
#else
fprintf(fp, "%d\t%s\t%s\t%s\t%s\n",
jid, i < nparams
? (char *)params[i].jp_value : argv[0],
argv[1], ip4_addr ? ip4_addr : "", argv[3]);
#endif
}
(void)fclose(fp);
}
if (cmdarg < 0)
exit(0);
if (username != NULL) {
if (Uflag)
GET_USER_INFO;
if (lflag) {
p = getenv("TERM");
environ = &cleanenv;
}
if (setgroups(ngroups, groups) != 0)
err(1, "setgroups");
if (setgid(pwd->pw_gid) != 0)
err(1, "setgid");
if (setusercontext(lcap, pwd, pwd->pw_uid,
LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
err(1, "setusercontext");
login_close(lcap);
}
if (lflag) {
if (*pwd->pw_shell)
shell = pwd->pw_shell;
else
shell = _PATH_BSHELL;
if (chdir(pwd->pw_dir) < 0)
errx(1, "no home directory");
setenv("HOME", pwd->pw_dir, 1);
setenv("SHELL", shell, 1);
setenv("USER", pwd->pw_name, 1);
if (p)
setenv("TERM", p, 1);
}
execvp(argv[cmdarg], argv + cmdarg);
err(1, "execvp: %s", argv[cmdarg]);
}
static void
add_ip_addr(char **addrp, char *value)
{
int addrlen;
char *addr;
if (!*addrp) {
*addrp = strdup(value);
if (!*addrp)
err(1, "malloc");
} else if (value[0]) {
addrlen = strlen(*addrp) + strlen(value) + 2;
addr = malloc(addrlen);
if (!addr)
err(1, "malloc");
snprintf(addr, addrlen, "%s,%s", *addrp, value);
free(*addrp);
*addrp = addr;
}
}
#ifdef INET6
static void
add_ip_addr46(char *value)
{
char *p, *np;
for (p = value;; p = np + 1)
{
np = strchr(p, ',');
if (np)
*np = '\0';
add_ip_addrinfo(AI_NUMERICHOST, p);
if (!np)
break;
}
}
#endif
static void
add_ip_addrinfo(int ai_flags, char *value)
{
struct addrinfo hints, *ai0, *ai;
struct in_addr addr4;
size_t size;
int error, ip4ok;
int mib[4];
char avalue4[INET_ADDRSTRLEN];
#ifdef INET6
struct in6_addr addr6;
int ip6ok;
char avalue6[INET6_ADDRSTRLEN];
#endif
/* Look up the hostname (or get the address) */
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_STREAM;
#ifdef INET6
hints.ai_family = PF_UNSPEC;
#else
hints.ai_family = PF_INET;
#endif
hints.ai_flags = ai_flags;
error = getaddrinfo(value, NULL, &hints, &ai0);
if (error != 0)
errx(1, "hostname %s: %s", value, gai_strerror(error));
/*
* Silently ignore unsupported address families from DNS lookups.
* But if this is a numeric address, let the kernel give the error.
*/
if (ai_flags & AI_NUMERICHOST)
ip4ok =
#ifdef INET6
ip6ok =
#endif
1;
else {
size = 4;
ip4ok = (sysctlnametomib("security.jail.param.ip4", mib,
&size) == 0);
#ifdef INET6
size = 4;
ip6ok = (sysctlnametomib("security.jail.param.ip6", mib,
&size) == 0);
#endif
}
/* Convert the addresses to ASCII so set_param can convert them back. */
for (ai = ai0; ai; ai = ai->ai_next)
switch (ai->ai_family) {
case AF_INET:
if (!ip4ok)
break;
memcpy(&addr4, &((struct sockaddr_in *)
(void *)ai->ai_addr)->sin_addr, sizeof(addr4));
if (inet_ntop(AF_INET, &addr4, avalue4,
INET_ADDRSTRLEN) == NULL)
err(1, "inet_ntop");
add_ip_addr(&ip4_addr, avalue4);
break;
#ifdef INET6
case AF_INET6:
if (!ip6ok)
break;
memcpy(&addr6, &((struct sockaddr_in6 *)
(void *)ai->ai_addr)->sin6_addr, sizeof(addr6));
if (inet_ntop(AF_INET6, &addr6, avalue6,
INET6_ADDRSTRLEN) == NULL)
err(1, "inet_ntop");
add_ip_addr(&ip6_addr, avalue6);
break;
#endif
}
freeaddrinfo(ai0);
}
static void
quoted_print(FILE *fp, char *str)
{
int c, qc;
char *p = str;
/* An empty string needs quoting. */
if (!*p) {
fputs("\"\"", fp);
return;
}
/*
* The value will be surrounded by quotes if it contains spaces
* or quotes.
*/
qc = strchr(p, '\'') ? '"'
: strchr(p, '"') ? '\''
: strchr(p, ' ') || strchr(p, '\t') ? '"'
: 0;
if (qc)
putc(qc, fp);
while ((c = *p++)) {
if (c == '\\' || c == qc)
putc('\\', fp);
putc(c, fp);
}
if (qc)
putc(qc, fp);
}
static void
set_param(const char *name, char *value)
{
struct jailparam *param;
int i;
static int paramlistsize;
/* Separate the name from the value, if not done already. */
if (name == NULL) {
name = value;
if ((value = strchr(value, '=')))
*value++ = '\0';
}
/* Check for repeat parameters */
for (i = 0; i < nparams; i++)
if (!strcmp(name, params[i].jp_name)) {
jailparam_free(params + i, 1);
memcpy(params + i, params + i + 1,
(--nparams - i) * sizeof(struct jailparam));
break;
}
/* Make sure there is room for the new param record. */
if (!nparams) {
paramlistsize = 32;
params = malloc(paramlistsize * sizeof(*params));
param_values = malloc(paramlistsize * sizeof(*param_values));
if (params == NULL || param_values == NULL)
err(1, "malloc");
} else if (nparams >= paramlistsize) {
paramlistsize *= 2;
params = realloc(params, paramlistsize * sizeof(*params));
param_values = realloc(param_values,
paramlistsize * sizeof(*param_values));
if (params == NULL)
err(1, "realloc");
}
/* Look up the paramter. */
param_values[nparams] = value;
param = params + nparams++;
if (jailparam_init(param, name) < 0 ||
jailparam_import(param, value) < 0)
errx(1, "%s", jail_errmsg);
}
static void
usage(void)
{
(void)fprintf(stderr,
"usage: jail [-d] [-h] [-i] [-J jid_file] "
"[-l -u username | -U username]\n"
" [-c | -m] param=value ... [command=command ...]\n"
" jail [-r jail]\n");
exit(1);
}