freebsd-skq/lib/libjail/jail_getid.c
kevans ebec61f967 jail_getid(3): add special-case immediate return for jid 0
As depicted in the comment: jid 0 always exists, but the lookup will fail as
it does not appear in the kernel's alljails list being a special jail. Some
callers will expect/rely on this, and we have no reason to lie because it
does always exist.

Reported by:	Stefan Hegnauer <stefan.hegnauer gmx ch>
MFC after:	soon (regression, breaks inspecting jail host bits, partial
revert)
2019-06-02 14:03:56 +00:00

125 lines
3.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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/types.h>
#include <sys/jail.h>
#include <sys/uio.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jail.h"
/*
* Return the JID corresponding to a jail name.
*/
int
jail_getid(const char *name)
{
char *ep;
int jid;
struct iovec jiov[4];
jid = strtoul(name, &ep, 10);
if (*name && !*ep) {
/*
* jid == 0 is a special case; it will not appear in the
* kernel's jail list, but naturally processes will be assigned
* to it because it is prison 0. Trivially return this one
* without a trip to the kernel, because it always exists but
* the lookup won't succeed.
*/
if (jid == 0)
return jid;
jiov[0].iov_base = __DECONST(char *, "jid");
jiov[0].iov_len = sizeof("jid");
jiov[1].iov_base = &jid;
jiov[1].iov_len = sizeof(jid);
} else {
jiov[0].iov_base = __DECONST(char *, "name");
jiov[0].iov_len = sizeof("name");
jiov[1].iov_len = strlen(name) + 1;
jiov[1].iov_base = alloca(jiov[1].iov_len);
strcpy(jiov[1].iov_base, name);
}
jiov[2].iov_base = __DECONST(char *, "errmsg");
jiov[2].iov_len = sizeof("errmsg");
jiov[3].iov_base = jail_errmsg;
jiov[3].iov_len = JAIL_ERRMSGLEN;
jail_errmsg[0] = 0;
jid = jail_get(jiov, 4, 0);
if (jid < 0 && !jail_errmsg[0])
snprintf(jail_errmsg, JAIL_ERRMSGLEN, "jail_get: %s",
strerror(errno));
return jid;
}
/*
* Return the name corresponding to a JID.
*/
char *
jail_getname(int jid)
{
struct iovec jiov[6];
char *name;
char namebuf[MAXHOSTNAMELEN];
jiov[0].iov_base = __DECONST(char *, "jid");
jiov[0].iov_len = sizeof("jid");
jiov[1].iov_base = &jid;
jiov[1].iov_len = sizeof(jid);
jiov[2].iov_base = __DECONST(char *, "name");
jiov[2].iov_len = sizeof("name");
jiov[3].iov_base = namebuf;
jiov[3].iov_len = sizeof(namebuf);
jiov[4].iov_base = __DECONST(char *, "errmsg");
jiov[4].iov_len = sizeof("errmsg");
jiov[5].iov_base = jail_errmsg;
jiov[5].iov_len = JAIL_ERRMSGLEN;
jail_errmsg[0] = 0;
jid = jail_get(jiov, 6, 0);
if (jid < 0) {
if (!jail_errmsg[0])
snprintf(jail_errmsg, JAIL_ERRMSGLEN, "jail_get: %s",
strerror(errno));
return NULL;
} else {
name = strdup(namebuf);
if (name == NULL)
strerror_r(errno, jail_errmsg, JAIL_ERRMSGLEN);
}
return name;
}