freebsd-nq/sys/kern/kern_jail.c

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This Implements the mumbled about "Jail" feature. This is a seriously beefed up chroot kind of thing. The process is jailed along the same lines as a chroot does it, but with additional tough restrictions imposed on what the superuser can do. For all I know, it is safe to hand over the root bit inside a prison to the customer living in that prison, this is what it was developed for in fact: "real virtual servers". Each prison has an ip number associated with it, which all IP communications will be coerced to use and each prison has its own hostname. Needless to say, you need more RAM this way, but the advantage is that each customer can run their own particular version of apache and not stomp on the toes of their neighbors. It generally does what one would expect, but setting up a jail still takes a little knowledge. A few notes: I have no scripts for setting up a jail, don't ask me for them. The IP number should be an alias on one of the interfaces. mount a /proc in each jail, it will make ps more useable. /proc/<pid>/status tells the hostname of the prison for jailed processes. Quotas are only sensible if you have a mountpoint per prison. There are no privisions for stopping resource-hogging. Some "#ifdef INET" and similar may be missing (send patches!) If somebody wants to take it from here and develop it into more of a "virtual machine" they should be most welcome! Tools, comments, patches & documentation most welcome. Have fun... Sponsored by: http://www.rndassociates.com/ Run for almost a year by: http://www.servetheweb.com/
1999-04-28 11:38:52 +00:00
#include <sys/param.h>
#include <sys/types.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/sysproto.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/jail.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
int
jail(p, uap)
struct proc *p;
struct jail_args /* {
syscallarg(struct jail *) jail;
} */ *uap;
{
int error;
struct prison *pr;
struct jail j;
struct chroot_args ca;
error = suser(p);
if (error)
return (error);
error = copyin(uap->jail, &j, sizeof j);
if (error)
return (error);
MALLOC(pr, struct prison *, sizeof *pr , M_PRISON, M_WAITOK);
bzero((caddr_t)pr, sizeof *pr);
error = copyinstr(j.hostname, &pr->pr_host, sizeof pr->pr_host, 0);
if (error)
goto bail;
pr->pr_ip = j.ip_number;
ca.path = j.path;
error = chroot(p, &ca);
if (error)
goto bail;
pr->pr_ref++;
p->p_prison = pr;
p->p_flag |= P_JAILED;
return (0);
bail:
FREE(pr, M_PRISON);
return (error);
}
int
prison_ip(struct proc *p, int flag, u_int32_t *ip)
{
u_int32_t tmp;
if (!p->p_prison)
return (0);
if (flag)
tmp = *ip;
else
tmp = ntohl(*ip);
if (tmp == INADDR_ANY) {
if (flag)
*ip = p->p_prison->pr_ip;
else
*ip = htonl(p->p_prison->pr_ip);
return (0);
}
if (p->p_prison->pr_ip != tmp)
return (1);
return (0);
}
void
prison_remote_ip(struct proc *p, int flag, u_int32_t *ip)
{
u_int32_t tmp;
if (!p->p_prison)
return;
if (flag)
tmp = *ip;
else
tmp = ntohl(*ip);
if (tmp == 0x7f000001) {
if (flag)
*ip = p->p_prison->pr_ip;
else
*ip = htonl(p->p_prison->pr_ip);
return;
}
return;
}
int
prison_if(struct proc *p, struct sockaddr *sa)
{
struct sockaddr_in *sai = (struct sockaddr_in*) sa;
int ok;
if (sai->sin_family != AF_INET)
ok = 0;
else if (p->p_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
ok = 1;
else
ok = 0;
return (ok);
}