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a2f2b3afcd
- Add proc locking to the jail() syscall. This mostly involved shuffling a few things around so that blockable things like malloc and copyin were performed before acquiring the lock and checking the existing ucred and then updating the ucred as one "atomic" change under the proc lock.
222 lines
4.4 KiB
C
222 lines
4.4 KiB
C
/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/errno.h>
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#include <sys/sysproto.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/jail.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <netinet/in.h>
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MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
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SYSCTL_NODE(, OID_AUTO, jail, CTLFLAG_RW, 0,
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"Jail rules");
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mp_fixme("these variables need a lock")
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int jail_set_hostname_allowed = 1;
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SYSCTL_INT(_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
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&jail_set_hostname_allowed, 0,
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"Processes in jail can set their hostnames");
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int jail_socket_unixiproute_only = 1;
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SYSCTL_INT(_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
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&jail_socket_unixiproute_only, 0,
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"Processes in jail are limited to creating UNIX/IPv4/route sockets only");
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int jail_sysvipc_allowed = 0;
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SYSCTL_INT(_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
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&jail_sysvipc_allowed, 0,
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"Processes in jail can use System V IPC primitives");
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/*
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* MPSAFE
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*/
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int
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jail(td, uap)
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struct thread *td;
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struct jail_args /* {
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syscallarg(struct jail *) jail;
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} */ *uap;
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{
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struct proc *p = td->td_proc;
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int error;
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struct prison *pr;
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struct jail j;
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struct chroot_args ca;
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struct ucred *newcred = NULL, *oldcred;
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error = copyin(uap->jail, &j, sizeof j);
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if (error)
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return (error);
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if (j.version != 0)
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return (EINVAL);
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mtx_lock(&Giant);
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MALLOC(pr, struct prison *, sizeof *pr , M_PRISON, M_WAITOK | M_ZERO);
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pr->pr_securelevel = securelevel;
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error = copyinstr(j.hostname, &pr->pr_host, sizeof pr->pr_host, 0);
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if (error)
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goto bail;
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ca.path = j.path;
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error = chroot(td, &ca);
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if (error)
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goto bail;
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newcred = crget();
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pr->pr_ip = j.ip_number;
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PROC_LOCK(p);
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/* Implicitly fail if already in jail. */
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error = suser(p);
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if (error)
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goto badcred;
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oldcred = p->p_ucred;
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crcopy(newcred, oldcred);
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p->p_ucred = newcred;
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p->p_ucred->cr_prison = pr;
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pr->pr_ref = 1;
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PROC_UNLOCK(p);
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crfree(oldcred);
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mtx_unlock(&Giant);
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return (0);
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badcred:
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PROC_UNLOCK(p);
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crfree(newcred);
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bail:
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FREE(pr, M_PRISON);
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mtx_unlock(&Giant);
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return (error);
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}
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void
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prison_free(struct prison *pr)
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{
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pr->pr_ref--;
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if (pr->pr_ref == 0) {
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if (pr->pr_linux != NULL)
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FREE(pr->pr_linux, M_PRISON);
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FREE(pr, M_PRISON);
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}
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}
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void
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prison_hold(struct prison *pr)
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{
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pr->pr_ref++;
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}
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int
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prison_ip(struct ucred *cred, int flag, u_int32_t *ip)
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{
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u_int32_t tmp;
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if (!jailed(cred))
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return (0);
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if (flag)
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tmp = *ip;
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else
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tmp = ntohl(*ip);
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if (tmp == INADDR_ANY) {
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if (flag)
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*ip = cred->cr_prison->pr_ip;
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else
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*ip = htonl(cred->cr_prison->pr_ip);
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return (0);
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}
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if (tmp == INADDR_LOOPBACK) {
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if (flag)
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*ip = cred->cr_prison->pr_ip;
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else
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*ip = htonl(cred->cr_prison->pr_ip);
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return (0);
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}
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if (cred->cr_prison->pr_ip != tmp)
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return (1);
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return (0);
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}
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void
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prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip)
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{
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u_int32_t tmp;
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if (!jailed(cred))
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return;
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if (flag)
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tmp = *ip;
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else
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tmp = ntohl(*ip);
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if (tmp == INADDR_LOOPBACK) {
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if (flag)
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*ip = cred->cr_prison->pr_ip;
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else
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*ip = htonl(cred->cr_prison->pr_ip);
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return;
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}
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return;
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}
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int
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prison_if(struct ucred *cred, struct sockaddr *sa)
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{
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struct sockaddr_in *sai = (struct sockaddr_in*) sa;
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int ok;
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if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
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ok = 1;
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else if (sai->sin_family != AF_INET)
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ok = 0;
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else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
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ok = 1;
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else
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ok = 0;
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return (ok);
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}
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/*
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* Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
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*/
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int
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prison_check(cred1, cred2)
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struct ucred *cred1, *cred2;
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{
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if (jailed(cred1)) {
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if (!jailed(cred2))
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return (ESRCH);
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if (cred2->cr_prison != cred1->cr_prison)
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return (ESRCH);
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}
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return (0);
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}
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/*
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* Return 1 if the passed credential is in a jail, otherwise 0.
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*/
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int
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jailed(cred)
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struct ucred *cred;
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{
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return (cred->cr_prison != NULL);
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}
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