3 files changed, 213 insertions, 77 deletions

diff --git a/usr.sbin/jexec/Makefile b/usr.sbin/jexec/Makefile
index 2bf817cb84b6b..049ccd46e2e28 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 40c4979ad494a..bdda23d0209b3 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 137eec310a8d7..69bc8f02448a0 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);
-}