MFp4:

  Bring in updated jail support from bz_jail branch.

This enhances the current jail implementation to permit multiple
addresses per jail. In addtion to IPv4, IPv6 is supported as well.
Due to updated checks it is even possible to have jails without
an IP address at all, which basically gives one a chroot with
restricted process view, no networking,..

SCTP support was updated and supports IPv6 in jails as well.

Cpuset support permits jails to be bound to specific processor
sets after creation.

Jails can have an unrestricted (no duplicate protection, etc.) name
in addition to the hostname. The jail name cannot be changed from
within a jail and is considered to be used for management purposes
or as audit-token in the future.

DDB 'show jails' command was added to aid debugging.

Proper compat support permits 32bit jail binaries to be used on 64bit
systems to manage jails. Also backward compatibility was preserved where
possible: for jail v1 syscalls, as well as with user space management
utilities.

Both jail as well as prison version were updated for the new features.
A gap was intentionally left as the intermediate versions had been
used by various patches floating around the last years.

Bump __FreeBSD_version for the afore mentioned and in kernel changes.

Special thanks to:
- Pawel Jakub Dawidek (pjd) for his multi-IPv4 patches
  and Olivier Houchard (cognet) for initial single-IPv6 patches.
- Jeff Roberson (jeff) and Randall Stewart (rrs) for their
  help, ideas and review on cpuset and SCTP support.
- Robert Watson (rwatson) for lots and lots of help, discussions,
  suggestions and review of most of the patch at various stages.
- John Baldwin (jhb) for his help.
- Simon L. Nielsen (simon) as early adopter testing changes
  on cluster machines as well as all the testers and people
  who provided feedback the last months on freebsd-jail and
  other channels.
- My employer, CK Software GmbH, for the support so I could work on this.

Reviewed by:	(see above)
MFC after:	3 months (this is just so that I get the mail)
X-MFC Before:   7.2-RELEASE if possible

3 files changed, 213 insertions, 77 deletions

diff --git a/usr.sbin/jexec/Makefile b/usr.sbin/jexec/Makefile
index 2bf817c..049ccd4 100644
--- a/usr.sbin/jexec/Makefile
+++ b/usr.sbin/jexec/Makefile
@@ -6,4 +6,6 @@ DPADD=	${LIBUTIL}
 LDADD=	-lutil
 WARNS?=	6
 
+CFLAGS+= -DSUPPORT_OLD_XPRISON
+
 .include <bsd.prog.mk>
diff --git a/usr.sbin/jexec/jexec.8 b/usr.sbin/jexec/jexec.8
index 40c4979..bdda23d 100644
--- a/usr.sbin/jexec/jexec.8
+++ b/usr.sbin/jexec/jexec.8
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 26, 2008
+.Dd November 29, 2008
 .Dt JEXEC 8
 .Os
 .Sh NAME
@@ -34,22 +34,36 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl u Ar username | Fl U Ar username
-.Op Fl h Ar hostname | Fl h Ar ip-number | Ar jid
-.Ar command ...
+.Op Fl n Ar jailname
+.Ar jid command ...
 .Sh DESCRIPTION
 The
 .Nm
 utility executes
 .Ar command
-inside the jail identified by
-.Ar hostname 
+inside the jail identified by either
+.Ar jailname
 or
-.Ar ip-number 
-or
-.Ar jid .
+.Ar jid
+or both.
+.Pp
+If the jail cannot be identified uniquely by the given parameters,
+an error message is printed.
+.Nm
+will also check the state of the jail (once supported) to be
+.Dv ALIVE
+and ignore jails in other states.
+The mandatory argument
+.Ar jid
+is the unique jail identifier as given by
+.Xr jls 8 .
+In case you only want to match on other criteria, give an empty string.
 .Pp
 The following options are available:
 .Bl -tag -width indent
+.It Fl n Ar jailname
+The name of the jail, if given upon creation of the jail.
+This is not the hostname of the jail.
 .It Fl u Ar username
 The user name from host environment as whom the
 .Ar command
@@ -59,9 +73,6 @@ The user name from jailed environment as whom the
 .Ar command
 should run.
 .El
-.Sh "CAUTIONS"
-Only jid is guaranteed to uniquely identify a jail.
-Hostname or ip-number only work here if matched to one unique jail.
 .Sh SEE ALSO
 .Xr jail_attach 2 ,
 .Xr jail 8 ,
@@ -71,3 +82,13 @@ The
 .Nm
 utility was added in
 .Fx 5.1 .
+.Sh BUGS
+If the jail is not identified by
+.Ar jid
+there is a possible race in between the lookup of the jail
+and executing the command inside the jail.
+Giving a
+.Ar jid
+has a similar race as another process can stop the jail and
+start another one after the user looked up the
+.Ar jid .
diff --git a/usr.sbin/jexec/jexec.c b/usr.sbin/jexec/jexec.c
index 137eec3..69bc8f0 100644
--- a/usr.sbin/jexec/jexec.c
+++ b/usr.sbin/jexec/jexec.c
@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
+ * Copyright (c) 2008 Bjoern A. Zeeb <bz@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,20 +31,171 @@
 #include <sys/jail.h>
 #include <sys/sysctl.h>
 
-#include <arpa/inet.h>
+#include <netinet/in.h>
 
 #include <err.h>
 #include <errno.h>
-#include <limits.h>
 #include <login_cap.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <pwd.h>
 #include <unistd.h>
-#include <string.h>
 
 static void	usage(void);
-static int	addr2jid(const char *addr);
+
+#ifdef SUPPORT_OLD_XPRISON
+static
+char *lookup_xprison_v1(void *p, char *end, int *id)
+{
+	struct xprison_v1 *xp;
+
+	if (id == NULL)
+		errx(1, "Internal error. Invalid ID pointer.");
+
+	if ((char *)p + sizeof(struct xprison_v1) > end)
+		errx(1, "Invalid length for jail");
+
+	xp = (struct xprison_v1 *)p;
+
+	*id = xp->pr_id;
+	return ((char *)(xp + 1));
+}
+#endif
+
+static
+char *lookup_xprison_v3(void *p, char *end, int *id, char *jailname)
+{
+	struct xprison *xp;
+	char *q;
+	int ok;
+
+	if (id == NULL)
+		errx(1, "Internal error. Invalid ID pointer.");
+
+	if ((char *)p + sizeof(struct xprison) > end)
+		errx(1, "Invalid length for jail");
+
+	xp = (struct xprison *)p;
+	ok = 1;
+
+	/* Jail state and name. */
+	if (xp->pr_state < 0 || xp->pr_state >
+	    (int)((sizeof(prison_states) / sizeof(struct prison_state))))
+		errx(1, "Invalid jail state.");
+	else if (xp->pr_state != PRISON_STATE_ALIVE)
+		ok = 0;
+	if (jailname != NULL) {
+		if (xp->pr_name == NULL)
+			ok = 0;
+		else if (strcmp(jailname, xp->pr_name) != 0)
+			ok = 0;
+	}
+
+	q = (char *)(xp + 1);
+	/* IPv4 addresses. */
+	q += (xp->pr_ip4s * sizeof(struct in_addr));
+	if ((char *)q > end)
+		errx(1, "Invalid length for jail");
+	/* IPv6 addresses. */
+	q += (xp->pr_ip6s * sizeof(struct in6_addr));
+	if ((char *)q > end)
+		errx(1, "Invalid length for jail");
+
+	if (ok)
+		*id = xp->pr_id;
+	return (q);
+}
+
+static int
+lookup_jail(int jid, char *jailname)
+{
+	size_t i, j, len;
+	void *p, *q;
+	int version, id, xid, count;
+
+	if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1)
+		err(1, "sysctlbyname(): security.jail.list");
+
+	j = len;
+	for (i = 0; i < 4; i++) {
+		if (len <= 0)
+			exit(0);	
+		p = q = malloc(len);
+		if (p == NULL)
+			err(1, "malloc()");
+
+		if (sysctlbyname("security.jail.list", q, &len, NULL, 0) == -1) {
+			if (errno == ENOMEM) {
+				free(p);
+				p = NULL;
+				len += j;
+				continue;
+			}
+			err(1, "sysctlbyname(): security.jail.list");
+		}
+		break;
+	}
+	if (p == NULL)
+		err(1, "sysctlbyname(): security.jail.list");
+	if (len < sizeof(int))
+		errx(1, "This is no prison. Kernel and userland out of sync?");
+	version = *(int *)p;
+	if (version > XPRISON_VERSION)
+		errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
+
+	count = 0;
+	xid = -1;
+	for (; q != NULL && (char *)q + sizeof(int) < (char *)p + len;) {
+		version = *(int *)q;
+		if (version > XPRISON_VERSION)
+			errx(1, "Sci-Fi prison. Kernel/userland out of sync?");
+		id = -1;
+		switch (version) {
+#ifdef SUPPORT_OLD_XPRISON
+		case 1:
+			if (jailname != NULL)
+				errx(1, "Version 1 prisons did not "
+				    "support jail names.");
+			q = lookup_xprison_v1(q, (char *)p + len, &id);
+			break;
+		case 2:
+			errx(1, "Version 2 was used by multi-IPv4 jail "
+			    "implementations that never made it into the "
+			    "official kernel.");
+			/* NOTREACHED */
+			break;
+#endif
+		case 3:
+			q = lookup_xprison_v3(q, (char *)p + len, &id, jailname);
+			break;
+		default:
+			errx(1, "Prison unknown. Kernel/userland out of sync?");
+			/* NOTREACHED */
+			break;
+		}
+		/* Possible match. */
+		if (id > 0) {
+			/* Do we have a jail ID to match as well? */
+			if (jid > 0) {
+				if (jid == id) {
+					xid = id;
+					count++;
+				}
+			} else {
+				xid = id;
+				count++;
+			}
+		}
+	}
+
+	free(p);
+
+	if (count != 1)
+		errx(1, "Could not uniquely identify the jail.");
+
+	return (xid);
+}
 
 #define GET_USER_INFO do {						\
 	pwd = getpwnam(username);					\
@@ -68,13 +220,18 @@ main(int argc, char *argv[])
 	login_cap_t *lcap = NULL;
 	struct passwd *pwd = NULL;
 	gid_t groups[NGROUPS];
-	int ch, ngroups, uflag, Uflag, hflag;
-	char *username;
-	ch = uflag = Uflag = hflag = 0;
-	username = NULL;
+	int ch, ngroups, uflag, Uflag;
+	char *jailname, *username;
+
+	ch = uflag = Uflag = 0;
+	jailname = username = NULL;
+	jid = -1;
 
-	while ((ch = getopt(argc, argv, "u:U:h")) != -1) {
+	while ((ch = getopt(argc, argv, "i:n:u:U:")) != -1) {
 		switch (ch) {
+		case 'n':
+			jailname = optarg;
+			break;
 		case 'u':
 			username = optarg;
 			uflag = 1;
@@ -83,9 +240,6 @@ main(int argc, char *argv[])
 			username = optarg;
 			Uflag = 1;
 			break;
-		case 'h':
-			hflag = 1;
-			break;
 		default:
 			usage();
 		}
@@ -94,15 +248,22 @@ main(int argc, char *argv[])
 	argv += optind;
 	if (argc < 2)
 		usage();
+	if (strlen(argv[0]) > 0) {
+		jid = (int)strtol(argv[0], NULL, 10);
+		if (errno)
+			err(1, "Unable to parse jail ID.");
+	}
+	if (jid <= 0 && jailname == NULL) {
+		fprintf(stderr, "Neither jail ID nor jail name given.\n");
+		usage();
+	}
 	if (uflag && Uflag)
 		usage();
 	if (uflag)
 		GET_USER_INFO;
-	if (hflag) {
-		if ((jid = addr2jid(argv[0])) == 0)
-			errx(1, "jail_attach(): Cannot convert %s to jid", argv[0]);
-	} else
-		jid = (int)strtol(argv[0], NULL, 10);
+	jid = lookup_jail(jid, jailname);
+	if (jid <= 0)
+		errx(1, "Cannot identify jail.");
 	if (jail_attach(jid) == -1)
 		err(1, "jail_attach(): %d", jid);
 	if (chdir("/") == -1)
@@ -130,54 +291,6 @@ usage(void)
 
 	fprintf(stderr, "%s%s\n",
 		"usage: jexec [-u username | -U username]",
-		" [-h hostname | -h ip-number | jid] command ...");
+		" [-n jailname] jid command ...");
 	exit(1); 
 }
-
-static int 
-addr2jid(const char *addr)
-{
-	struct xprison *sxp, *xp;
-	struct in_addr in;
-	size_t i, len;
-	int jid, cnt;
-	jid = cnt = 0;
-
-	if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1)
-		err(1, "sysctlbyname(): security.jail.list");
-	for (i = 0; i < 4; i++) {
-		if (len <= 0)
-			err(1, "sysctlbyname(): len <=0");
-		sxp = xp = malloc(len);
-		if (sxp == NULL)
-			err(1, "malloc()");
-		if (sysctlbyname("security.jail.list", xp, &len, NULL, 0) == -1) {
-			if (errno == ENOMEM) {
-				free(sxp);
-				sxp = NULL;
-				continue;
-			}
-			err(1, "sysctlbyname(): security.jail.list");
-		}
-		break;
-	}
-	if (sxp == NULL)
-		err(1, "sysctlbyname(): security.jail.list");
-	if (len < sizeof(*xp) || len % sizeof(*xp) ||
-	    xp->pr_version != XPRISON_VERSION)
-		errx(1, "Kernel and userland out of sync");
-	for (i = 0; i < len / sizeof(*xp); i++) {
-		in.s_addr = ntohl(xp->pr_ip);
-		if ((strcmp(inet_ntoa(in), addr) == 0) ||
-		    (strcmp(xp->pr_host, addr) == 0)) {
-			jid = xp->pr_id;
-			cnt++;
-		}
-		xp++;
-	}
-	free(sxp);
-	if (cnt == 1)
-		return (jid);
-	else
-		return(0);
-}