freebsd-dev/lib/libjail/jail_getid.c
Kyle Evans a9cefddd40 jail_getid(3): validate jid string input
Currently, if jail_getid(3) is passed in a numeric string, it assumes that
this is a jid string and passes it back converted to an int without checking
that it's a valid/existing jid. This breaks consumers that might use
jail_getid(3) to see if it can trivially grab a jid from a name if that name
happens to be numeric but not actually the name/jid of the jail. Instead of
returning -1 for the jail not existing, it'll return the int version of the
input and the consumer will not fallback to trying other methods.

Pass the numeric input to jail_get(2) as the jid for validation, rather than
the name. This works well- the kernel enforces that jid=name if name is
numeric, so doing the safe thing and checking numeric input as a jid will
still DTRT based on the description of jail_getid.

Reported by:	Wes Maag
Reviewed by:	jamie, Wes Maag
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D20388
2019-05-24 01:28:07 +00:00

116 lines
3.3 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) {
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;
}