1 files changed, 449 insertions, 0 deletions
diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
new file mode 100644
index 0000000..2241dd6
--- /dev/null
+++ b/sys/kern/kern_jail.c
@@ -0,0 +1,449 @@
+/*
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#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/lock.h>
+#include <sys/mutex.h>
+#include <sys/namei.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
+#include <sys/syscallsubr.h>
+#include <sys/sysctl.h>
+#include <sys/vnode.h>
+#include <net/if.h>
+#include <netinet/in.h>
+
+MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
+
+SYSCTL_DECL(_security);
+SYSCTL_NODE(_security, OID_AUTO, jail, CTLFLAG_RW, 0,
+    "Jail rules");
+
+mp_fixme("these variables need a lock")
+
+int	jail_set_hostname_allowed = 1;
+SYSCTL_INT(_security_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
+    &jail_set_hostname_allowed, 0,
+    "Processes in jail can set their hostnames");
+
+int	jail_socket_unixiproute_only = 1;
+SYSCTL_INT(_security_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
+    &jail_socket_unixiproute_only, 0,
+    "Processes in jail are limited to creating UNIX/IPv4/route sockets only");
+
+int	jail_sysvipc_allowed = 0;
+SYSCTL_INT(_security_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
+    &jail_sysvipc_allowed, 0,
+    "Processes in jail can use System V IPC primitives");
+
+/* allprison, lastprid, and prisoncount are protected by allprison_mtx. */
+struct	prisonlist allprison;
+struct	mtx allprison_mtx;
+int	lastprid = 0;
+int	prisoncount = 0;
+
+static void		 init_prison(void *);
+static struct prison	*prison_find(int);
+static int		 sysctl_jail_list(SYSCTL_HANDLER_ARGS);
+
+static void
+init_prison(void *data __unused)
+{
+
+	mtx_init(&allprison_mtx, "allprison", NULL, MTX_DEF);
+	LIST_INIT(&allprison);
+}
+
+SYSINIT(prison, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_prison, NULL);
+
+/*
+ * MPSAFE
+ *
+ * struct jail_args {
+ *	struct jail *jail;
+ * };
+ */
+int
+jail(struct thread *td, struct jail_args *uap)
+{
+	struct nameidata nd;
+	struct prison *pr, *tpr;
+	struct jail j;
+	struct jail_attach_args jaa;
+	int error, tryprid;
+
+	error = copyin(uap->jail, &j, sizeof(j));
+	if (error)
+		return (error);
+	if (j.version != 0)
+		return (EINVAL);
+
+	MALLOC(pr, struct prison *, sizeof(*pr), M_PRISON, M_WAITOK | M_ZERO);
+	mtx_init(&pr->pr_mtx, "jail mutex", NULL, MTX_DEF);
+	pr->pr_ref = 1;
+	error = copyinstr(j.path, &pr->pr_path, sizeof(pr->pr_path), 0);
+	if (error)
+		goto e_killmtx;
+	mtx_lock(&Giant);
+	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, pr->pr_path, td);
+	error = namei(&nd);
+	if (error) {
+		mtx_unlock(&Giant);
+		goto e_killmtx;
+	}
+	pr->pr_root = nd.ni_vp;
+	VOP_UNLOCK(nd.ni_vp, 0, td);
+	NDFREE(&nd, NDF_ONLY_PNBUF);
+	mtx_unlock(&Giant);
+	error = copyinstr(j.hostname, &pr->pr_host, sizeof(pr->pr_host), 0);
+	if (error)
+		goto e_dropvnref;
+	pr->pr_ip = j.ip_number;
+	pr->pr_linux = NULL;
+	pr->pr_securelevel = securelevel;
+
+	/* Determine next pr_id and add prison to allprison list. */
+	mtx_lock(&allprison_mtx);
+	tryprid = lastprid + 1;
+	if (tryprid == JAIL_MAX)
+		tryprid = 1;
+next:
+	LIST_FOREACH(tpr, &allprison, pr_list) {
+		if (tpr->pr_id == tryprid) {
+			tryprid++;
+			if (tryprid == JAIL_MAX) {
+				mtx_unlock(&allprison_mtx);
+				error = EAGAIN;
+				goto e_dropvnref;
+			}
+			goto next;
+		}
+	}
+	pr->pr_id = jaa.jid = lastprid = tryprid;
+	LIST_INSERT_HEAD(&allprison, pr, pr_list);
+	prisoncount++;
+	mtx_unlock(&allprison_mtx);
+
+	error = jail_attach(td, &jaa);
+	if (error)
+		goto e_dropprref;
+	mtx_lock(&pr->pr_mtx);
+	pr->pr_ref--;
+	mtx_unlock(&pr->pr_mtx);
+	td->td_retval[0] = jaa.jid;
+	return (0);
+e_dropprref:
+	mtx_lock(&allprison_mtx);
+	LIST_REMOVE(pr, pr_list);
+	prisoncount--;
+	mtx_unlock(&allprison_mtx);
+e_dropvnref:
+	mtx_lock(&Giant);
+	vrele(pr->pr_root);
+	mtx_unlock(&Giant);
+e_killmtx:
+	mtx_destroy(&pr->pr_mtx);
+	FREE(pr, M_PRISON);
+	return (error);
+}
+
+/*
+ * MPSAFE
+ *
+ * struct jail_attach_args {
+ *	int jid;
+ * };
+ */
+int
+jail_attach(struct thread *td, struct jail_attach_args *uap)
+{
+	struct proc *p;
+	struct ucred *newcred, *oldcred;
+	struct prison *pr;
+	int error;
+	
+	p = td->td_proc;
+
+	mtx_lock(&allprison_mtx);
+	pr = prison_find(uap->jid);
+	if (pr == NULL) {
+		mtx_unlock(&allprison_mtx);
+		return (EINVAL);
+	}
+	pr->pr_ref++;
+	mtx_unlock(&pr->pr_mtx);
+	mtx_unlock(&allprison_mtx);
+
+	error = suser_cred(td->td_ucred, PRISON_ROOT);
+	if (error)
+		goto e_dropref;
+	mtx_lock(&Giant);
+	vn_lock(pr->pr_root, LK_EXCLUSIVE | LK_RETRY, td);
+	if ((error = change_dir(pr->pr_root, td)) != 0)
+		goto e_unlock;
+#ifdef MAC
+	if ((error = mac_check_vnode_chroot(td->td_ucred, pr->pr_root)))
+		goto e_unlock;
+#endif
+	VOP_UNLOCK(pr->pr_root, 0, td);
+	change_root(pr->pr_root, td);
+	mtx_unlock(&Giant);
+
+	newcred = crget();
+	PROC_LOCK(p);
+	/* Implicitly fail if already in jail.  */
+	error = suser_cred(p->p_ucred, 0);
+	if (error) {
+		PROC_UNLOCK(p);
+		crfree(newcred);
+		goto e_dropref;
+	}
+	oldcred = p->p_ucred;
+	setsugid(p);
+	crcopy(newcred, oldcred);
+	newcred->cr_prison = pr;
+	p->p_ucred = newcred;
+	PROC_UNLOCK(p);
+	crfree(oldcred);
+	return (0);
+e_unlock:
+	VOP_UNLOCK(pr->pr_root, 0, td);
+	mtx_unlock(&Giant);
+e_dropref:
+	mtx_lock(&pr->pr_mtx);
+	pr->pr_ref--;
+	mtx_unlock(&pr->pr_mtx);
+	return (error);
+}
+
+/*
+ * Returns a locked prison instance, or NULL on failure.
+ */
+static struct prison *
+prison_find(int prid)
+{
+	struct prison *pr;
+
+	mtx_assert(&allprison_mtx, MA_OWNED);
+	LIST_FOREACH(pr, &allprison, pr_list) {
+		if (pr->pr_id == prid) {
+			mtx_lock(&pr->pr_mtx);
+			return (pr);
+		}
+	}
+	return (NULL);
+}
+
+void
+prison_free(struct prison *pr)
+{
+
+	mtx_assert(&Giant, MA_OWNED);
+	mtx_lock(&allprison_mtx);
+	mtx_lock(&pr->pr_mtx);
+	pr->pr_ref--;
+	if (pr->pr_ref == 0) {
+		LIST_REMOVE(pr, pr_list);
+		mtx_unlock(&pr->pr_mtx);
+		prisoncount--;
+		mtx_unlock(&allprison_mtx);
+		vrele(pr->pr_root);
+		mtx_destroy(&pr->pr_mtx);
+		if (pr->pr_linux != NULL)
+			FREE(pr->pr_linux, M_PRISON);
+		FREE(pr, M_PRISON);
+		return;
+	}
+	mtx_unlock(&pr->pr_mtx);
+	mtx_unlock(&allprison_mtx);
+}
+
+void
+prison_hold(struct prison *pr)
+{
+
+	mtx_lock(&pr->pr_mtx);
+	pr->pr_ref++;
+	mtx_unlock(&pr->pr_mtx);
+}
+
+u_int32_t
+prison_getip(struct ucred *cred)
+{
+
+	return (cred->cr_prison->pr_ip);
+}
+
+int
+prison_ip(struct ucred *cred, int flag, u_int32_t *ip)
+{
+	u_int32_t tmp;
+
+	if (!jailed(cred))
+		return (0);
+	if (flag) 
+		tmp = *ip;
+	else
+		tmp = ntohl(*ip);
+	if (tmp == INADDR_ANY) {
+		if (flag) 
+			*ip = cred->cr_prison->pr_ip;
+		else
+			*ip = htonl(cred->cr_prison->pr_ip);
+		return (0);
+	}
+	if (tmp == INADDR_LOOPBACK) {
+		if (flag)
+			*ip = cred->cr_prison->pr_ip;
+		else
+			*ip = htonl(cred->cr_prison->pr_ip);
+		return (0);
+	}
+	if (cred->cr_prison->pr_ip != tmp)
+		return (1);
+	return (0);
+}
+
+void
+prison_remote_ip(struct ucred *cred, int flag, u_int32_t *ip)
+{
+	u_int32_t tmp;
+
+	if (!jailed(cred))
+		return;
+	if (flag)
+		tmp = *ip;
+	else
+		tmp = ntohl(*ip);
+	if (tmp == INADDR_LOOPBACK) {
+		if (flag)
+			*ip = cred->cr_prison->pr_ip;
+		else
+			*ip = htonl(cred->cr_prison->pr_ip);
+		return;
+	}
+	return;
+}
+
+int
+prison_if(struct ucred *cred, struct sockaddr *sa)
+{
+	struct sockaddr_in *sai;
+	int ok;
+
+	sai = (struct sockaddr_in *)sa;
+	if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
+		ok = 1;
+	else if (sai->sin_family != AF_INET)
+		ok = 0;
+	else if (cred->cr_prison->pr_ip != ntohl(sai->sin_addr.s_addr))
+		ok = 1;
+	else
+		ok = 0;
+	return (ok);
+}
+
+/*
+ * Return 0 if jails permit p1 to frob p2, otherwise ESRCH.
+ */
+int
+prison_check(struct ucred *cred1, struct ucred *cred2)
+{
+
+	if (jailed(cred1)) {
+		if (!jailed(cred2))
+			return (ESRCH);
+		if (cred2->cr_prison != cred1->cr_prison)
+			return (ESRCH);
+	}
+
+	return (0);
+}
+
+/*
+ * Return 1 if the passed credential is in a jail, otherwise 0.
+ */
+int
+jailed(struct ucred *cred)
+{
+
+	return (cred->cr_prison != NULL);
+}
+
+/*
+ * Return the correct hostname for the passed credential.
+ */
+void
+getcredhostname(struct ucred *cred, char *buf, size_t size)
+{
+
+	if (jailed(cred)) {
+		mtx_lock(&cred->cr_prison->pr_mtx);
+		strlcpy(buf, cred->cr_prison->pr_host, size);
+		mtx_unlock(&cred->cr_prison->pr_mtx);
+	} else
+		strlcpy(buf, hostname, size);
+}
+
+static int
+sysctl_jail_list(SYSCTL_HANDLER_ARGS)
+{
+	struct xprison *xp, *sxp;
+	struct prison *pr;
+	int count, error;
+
+	mtx_assert(&Giant, MA_OWNED);
+retry:
+	mtx_lock(&allprison_mtx);
+	count = prisoncount;
+	mtx_unlock(&allprison_mtx);
+
+	if (count == 0)
+		return (0);
+
+	sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO);
+	mtx_lock(&allprison_mtx);
+	if (count != prisoncount) {
+		mtx_unlock(&allprison_mtx);
+		free(sxp, M_TEMP);
+		goto retry;
+	}
+	
+	LIST_FOREACH(pr, &allprison, pr_list) {
+		mtx_lock(&pr->pr_mtx);
+		xp->pr_version = XPRISON_VERSION;
+		xp->pr_id = pr->pr_id;
+		strlcpy(xp->pr_path, pr->pr_path, sizeof(xp->pr_path));
+		strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host));
+		xp->pr_ip = pr->pr_ip;
+		mtx_unlock(&pr->pr_mtx);
+		xp++;
+	}
+	mtx_unlock(&allprison_mtx);
+
+	error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count);
+	free(sxp, M_TEMP);
+	if (error)
+		return (error);
+	return (0);
+}
+
+SYSCTL_OID(_security_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD,
+    NULL, 0, sysctl_jail_list, "S", "List of active jails");