Re: [RFC] [PATCH] [2/3] LSM Stacking: stackable bsdjail (bsdjail lsm)

[Serge Hallyn <serue@us.ibm.com>]

This patch adds the bsdjail LSM as another test of stacking.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>

Index: linux-2.6.10-rc1-bk12-stack/security/Kconfig
===================================================================
--- linux-2.6.10-rc1-bk12-stack.orig/security/Kconfig	2004-11-02
20:05:25.000000000 -0600
+++ linux-2.6.10-rc1-bk12-stack/security/Kconfig	2004-11-02
20:05:46.000000000 -0600
@@ -95,6 +95,17 @@
 
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITY_BSDJAIL
+	tristate "BSD Jail LSM"
+	depends on SECURITY
+	select SECURITY_NETWORK
+	help
+	  Provides BSD Jail compartmentalization functionality.
+	  See Documentation/bsdjail.txt for more information and
+	  usage instructions.
+
+	  If you are unsure how to answer this question, answer N.
+
 source security/selinux/Kconfig
 
 config SECURITY_STACKER
Index: linux-2.6.10-rc1-bk12-stack/security/Makefile
===================================================================
--- linux-2.6.10-rc1-bk12-stack.orig/security/Makefile	2004-11-02
20:05:25.000000000 -0600
+++ linux-2.6.10-rc1-bk12-stack/security/Makefile	2004-11-02
20:05:46.000000000 -0600
@@ -18,3 +18,4 @@
 obj-$(CONFIG_SECURITY_CAPABILITIES)	+= commoncap.o capability.o
 obj-$(CONFIG_SECURITY_ROOTPLUG)		+= commoncap.o root_plug.o
 obj-$(CONFIG_SECURITY_SECLVL)		+= seclvl.o
+obj-$(CONFIG_SECURITY_BSDJAIL)		+= bsdjail.o
Index: linux-2.6.10-rc1-bk12-stack/security/bsdjail.c
===================================================================
--- linux-2.6.10-rc1-bk12-stack.orig/security/bsdjail.c	2004-11-02
13:46:30.056668176 -0600
+++ linux-2.6.10-rc1-bk12-stack/security/bsdjail.c	2004-11-02
20:29:19.142172288 -0600
@@ -0,0 +1,1365 @@
+/*
+ * File: linux/security/bsdjail.c
+ * Author: Serge Hallyn (serue@us.ibm.com)
+ * Date: Sep 12, 2004
+ *
+ * (See Documentation/bsdjail.txt for more information)
+ *
+ * Copyright (C) 2004 International Business Machines
<serue@us.ibm.com>
+ *
+ *   This program is free software; you can redistribute it and/or
modify
+ *   it under the terms of the GNU General Public License as published
by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/security.h>
+#include <linux/namei.h>
+#include <linux/namespace.h>
+#include <linux/proc_fs.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/pagemap.h>
+#include <linux/ip.h>
+#include <net/ipv6.h>
+#include <linux/mount.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/seq_file.h>
+#include <linux/un.h>
+#include <linux/smp_lock.h>
+#include <linux/kref.h>
+#include <asm/uaccess.h>
+
+static int jail_debug;
+module_param(jail_debug, int, 0);
+MODULE_PARM_DESC(jail_debug, "Print bsd jail debugging messages.\n");
+
+static int jail_idx;  /* index into security[CONFIG_NUM_LSMS] field */
+
+#define DBG 0
+#define WARN 1
+#define bsdj_debug(how, fmt, arg... ) \
+	do { \
+		if ( how || jail_debug ) \
+			printk(KERN_NOTICE "%s: %s: " fmt, \
+				MY_NAME, __FUNCTION__ , \
+				## arg ); \
+	} while ( 0 )
+
+#define MY_NAME "bsdjail"
+
+/* flag to keep track of how we were registered */
+static int secondary;
+
+/*
+ * The task structure holding jail information.
+ * Taskp->security points to one of these (or is null).
+ * There is exactly one jail_struct for each jail.  If >1 process
+ * are in the same jail, they share the same jail_struct.
+ */
+struct jail_struct {
+	struct kref		kref;
+
+	/* these are set on writes to /proc/<pid>/attr/exec */
+	char *ip4_addr_name;  /* char * containing ip4 addr to use for jail */
+	char *ip6_addr_name;  /* char * containing ip6 addr to use for jail */
+
+	/* these are set when a jail becomes active */
+	__u32 addr4;      	/* internal form of ip4_addr_name */
+	struct in6_addr addr6;	/* internal form of ip6_addr_name */
+
+	/* Resource limits.  0 = no limit */
+	int max_nrtask;		/* maximum number of tasks within this jail. */
+	int cur_nrtask;	/* current number of tasks within this jail. */
+	long maxtimeslice;      /* max timeslice in ms for procs in this jail
*/
+	long nice;      	/* nice level for processes in this jail */
+	long max_data, max_memlock;  /* equivalent to RLIMIT_{DATA, MEMLOCK}
*/
+/* values for the jail_flags field */
+#define IN_USE 1	 /* if 0, task is setting up jail, not yet in it */
+#define GOT_IPV4 2
+#define GOT_IPV6 4	 /* if 0, ipv4, else ipv6 */
+	char jail_flags;
+};
+
+/*
+ * disable_jail:  A jail which was in use, but has no references
+ * left, is disabled - we free up the mountpoint and dentry, and
+ * give up our reference on the module.
+ *
+ *   don't need to put namespace, it will be done automatically
+ *     when the last process in jail is put.
+ *   DO need to put the dentry and vfsmount
+ */
+static void
+disable_jail(struct jail_struct *tsec)
+{
+	module_put(THIS_MODULE);
+}
+
+
+static void free_jail(struct jail_struct *tsec)
+{
+	if (!tsec)
+		return;
+
+	kfree(tsec->ip4_addr_name);
+	kfree(tsec->ip6_addr_name);
+	kfree(tsec);
+}
+
+/* release_jail:
+ * Callback for kref_put to use for releasing a jail when its
+ * last user exits.
+ */
+static void release_jail(struct kref *kref)
+{
+	struct jail_struct *tsec;
+
+	tsec = container_of(kref, struct jail_struct, kref);
+	disable_jail(tsec);
+	free_jail(tsec);
+}
+
+/*
+ * jail_task_free_security: this is the callback hooked into LSM.
+ * If there was no task->security field for bsdjail, do nothing.
+ * If there was, but it was never put into use, free the jail.
+ * If there was, and the jail is in use, then decrement the usage
+ *  count, and disable and free the jail if the usage count hits 0.
+ */
+static void jail_task_free_security(struct task_struct *task)
+{
+	struct jail_struct *tsec = task->security[jail_idx];
+
+	if (!tsec)
+		return;
+
+	if (!(tsec->jail_flags & IN_USE)) {
+		/*
+		 * someone did 'echo -n x > /proc/<pid>/attr/exec' but
+		 * then forked before execing.  Nuke the old info.
+		 */
+		free_jail(tsec);
+		task->security[jail_idx] = NULL;
+		return;
+	}
+	tsec->cur_nrtask--;
+	/* If this was the last process in the jail, delete the jail */
+	kref_put(&tsec->kref, release_jail);
+}
+
+static struct jail_struct *
+alloc_task_security(struct task_struct *tsk)
+{
+	struct jail_struct *tsec;
+
+	tsec = kmalloc(sizeof(struct jail_struct), GFP_KERNEL);
+	if (tsec) {
+		memset(tsec, 0, sizeof(struct jail_struct));
+		tsk->security[jail_idx] = tsec;
+	}
+	return tsec;
+}
+
+static inline int
+in_jail(struct task_struct *t)
+{
+	struct jail_struct *tsec = t->security[jail_idx];
+
+	if (tsec && (tsec->jail_flags & IN_USE))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * If a network address was passed into /proc/<pid>/attr/exec,
+ * then process in its jail will only be allowed to bind/listen
+ * to that address.
+ */
+static void
+setup_netaddress(struct jail_struct *tsec)
+{
+	unsigned int a, b, c, d, i;
+	unsigned int x[8];
+
+	tsec->jail_flags &= ~(GOT_IPV4 | GOT_IPV6);
+	tsec->addr4 = 0;
+	ipv6_addr_set(&tsec->addr6, 0, 0, 0, 0);
+
+	if (tsec->ip4_addr_name) {
+		if (sscanf(tsec->ip4_addr_name, "%u.%u.%u.%u",
+					&a, &b, &c, &d) != 4)
+			return;
+		if (a>255 || b>255 || c>255 || d>255)
+			return;
+		tsec->addr4 = htonl((a<<24) | (b<<16) | (c<<8) | d);
+		tsec->jail_flags |= GOT_IPV4;
+		bsdj_debug(DBG, "Network (ipv4) set up (%s)\n",
+			tsec->ip4_addr_name);
+	}
+
+	if (tsec->ip6_addr_name) {
+		if (sscanf(tsec->ip6_addr_name, "%x:%x:%x:%x:%x:%x:%x:%x",
+			&x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &x[6],
+			&x[7]) != 8) {
+			printk(KERN_INFO "%s: bad ipv6 addr %s\n", __FUNCTION__,
+				tsec->ip6_addr_name);
+			return;
+		}
+		for (i=0; i<8; i++) {
+			if (x[i] > 65535) {
+				printk("%s: %x > 65535 at %d\n", __FUNCTION__, x[i], i);
+				return;
+			}
+			tsec->addr6.in6_u.u6_addr16[i] = htons(x[i]);
+		}
+		tsec->jail_flags |= GOT_IPV6;
+		bsdj_debug(DBG, "Network (ipv6) set up (%s)\n",
+			tsec->ip6_addr_name);
+	}
+}
+
+/*
+ * enable_jail:
+ * Called when a process is placed into a new jail to handle the
+ * actual creation of the jail.
+ *   Creates namespace
+ *   Stores the requested ip address
+ *   Registers a unique pseudo-proc filesystem for this jail
+ */
+static int enable_jail(struct task_struct *tsk)
+{
+	struct jail_struct *tsec = tsk->security[jail_idx];
+	int retval = -EFAULT;
+
+	if (!tsec)
+		goto out;
+
+	/* set up networking */
+	if (tsec->ip4_addr_name || tsec->ip6_addr_name)
+		setup_netaddress(tsec);
+
+	tsec->cur_nrtask = 1;
+	if (tsec->nice)
+		set_user_nice(current, tsec->nice);
+	if (tsec->max_data) {
+		current->signal->rlim[RLIMIT_DATA].rlim_cur = tsec->max_data;
+		current->signal->rlim[RLIMIT_DATA].rlim_max = tsec->max_data;
+	}
+	if (tsec->max_memlock) {
+		current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur =
+					tsec->max_memlock;
+		current->signal->rlim[RLIMIT_MEMLOCK].rlim_max =
+					tsec->max_memlock;
+	}
+	if (tsec->maxtimeslice) {
+		current->signal->rlim[RLIMIT_CPU].rlim_cur = tsec->maxtimeslice;
+		current->signal->rlim[RLIMIT_CPU].rlim_max = tsec->maxtimeslice;
+	}
+	/* success and end */
+	kref_init(&tsec->kref);
+	tsec->jail_flags |= IN_USE;
+
+	/* won't let ourselves be removed until this jail goes away */
+	try_module_get(THIS_MODULE);
+
+	return 0;
+
+out:
+	return retval;
+}
+
+/*
+ * LSM /proc/<pid>/attr hooks.
+ * You may write into /proc/<pid>/attr/exec:
+ *    lock  (no value, just to specify a jail)
+ *    ip 2.2.2.2
+ etc...
+ * These values will be used on the next exec() to set up your jail
+ *  (assuming you're not already in a jail)
+ */
+static int
+jail_setprocattr(struct task_struct *p, char *name, void *value, size_t
rsize)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+	long val;
+	char *v = value;
+	int start, len;
+	size_t size = rsize;
+
+	if (tsec && (tsec->jail_flags & IN_USE))
+		return -EINVAL;  /* let them guess why */
+
+	if (p != current || strcmp(name, "exec"))
+		return -EPERM;
+
+	if (!tsec) {
+		tsec = alloc_task_security(current);
+		if (!tsec)
+			return -ENOMEM;
+	}
+
+	if (v[size-1] == '\n')
+		size--;
+
+	if (strncmp(value, "ip ", 3) == 0) {
+		kfree(tsec->ip4_addr_name);
+		start = 3;
+		len = size - start + 1;
+		tsec->ip4_addr_name = kmalloc(len, GFP_KERNEL);
+		if (!tsec->ip4_addr_name)
+			return -ENOMEM;
+		strlcpy(tsec->ip4_addr_name, value+start, len);
+	} else if (strncmp(value, "ip6 ", 4) == 0) {
+		kfree(tsec->ip6_addr_name);
+		start = 4;
+		len = size - start + 1;
+		tsec->ip6_addr_name = kmalloc(len, GFP_KERNEL);
+		if (!tsec->ip6_addr_name)
+			return -ENOMEM;
+		strlcpy(tsec->ip6_addr_name, value+start, len);
+
+	/* the next two are equivalent */
+	} else if (strncmp(value, "slice ", 6) == 0) {
+		val = simple_strtoul(value+6, NULL, 0);
+		tsec->maxtimeslice = val;
+	} else if (strncmp(value, "timeslice ", 10) == 0) {
+		val = simple_strtoul(value+10, NULL, 0);
+		tsec->maxtimeslice = val;
+	} else if (strncmp(value, "nrtask ", 7) == 0) {
+		val = (int) simple_strtol(value+7, NULL, 0);
+		if (val < 1)
+			return -EINVAL;
+		tsec->max_nrtask = val;
+	} else if (strncmp(value, "memlock ", 8) == 0) {
+		val = simple_strtoul(value+8, NULL, 0);
+		tsec->max_memlock = val;
+	} else if (strncmp(value, "data ", 5) == 0) {
+		val = simple_strtoul(value+5, NULL, 0);
+		tsec->max_data = val;
+	} else if (strncmp(value, "nice ", 5) == 0) {
+		val = simple_strtoul(value+5, NULL, 0);
+		tsec->nice = val;
+	} else if (strncmp(value, "lock", 4) != 0)
+		return -EINVAL;
+
+	return rsize;
+}
+
+static int print_jail_net_info(struct jail_struct *j, char *buf, int
maxcnt)
+{
+	int len = 0;
+
+	if (j->ip4_addr_name)
+		len += snprintf(buf, maxcnt, "%s\n", j->ip4_addr_name);
+	if (j->ip6_addr_name)
+		len += snprintf(buf, maxcnt-len, "%s\n", j->ip6_addr_name);
+
+	return snprintf(buf, maxcnt, "No network information\n");
+}
+
+/*
+ * LSM /proc/<pid>/attr read hook.
+ *
+ * /proc/$$/attr/current output:
+ * If the reading process, say process 1001, is in a jail, then
+ *   cat /proc/999/attr/current
+ * will print networking information.
+ * If the reading process, say process 1001, is not in a jail, then
+ *   cat /proc/999/attr/current
+ * will return
+ *   ip:   (ip address of jail)
+ * if 999 is in a jail, or
+ *   -EINVAL
+ * if 999 is not in a jail.
+ *
+ * /proc/$$/attr/exec output:
+ * A process in a jail gets -EINVAL for /proc/$$/attr/exec.
+ * A process not in a jail gets hints on starting a jail.
+ */
+static int
+jail_getprocattr(struct task_struct *p, char *name, void *value, size_t
size)
+{
+	struct jail_struct *tsec;
+	int err = 0;
+
+	if (in_jail(current)) {
+		if (strcmp(name, "current") == 0) {
+			/* provide network info */
+			err = print_jail_net_info(current->security[jail_idx], value,
+				size);
+			return err;
+		}
+		return -EINVAL;  /* let them guess why */
+	}
+
+	if (strcmp(name, "exec") == 0) {
+		/* Print usage some help */
+		err = snprintf(value, size,
+			"Valid keywords:\n"
+			"lock\n"
+			"ip      <ip4-addr>\n"
+			"ip6     <ip6-addr>\n"
+			"nrtask  <max number of tasks in this jail>\n"
+			"nice    <nice level for processes in this jail>\n"
+			"slice   <max timeslice per process in msecs>\n"
+			"data    <max data size per process in bytes>\n"
+			"memlock <max lockable memory per process in bytes>\n");
+		return err;
+	}
+
+	if (strcmp(name, "current"))
+		return -EPERM;
+
+	tsec = p->security[jail_idx];
+	if (!tsec || !(tsec->jail_flags & IN_USE)) {
+		err = snprintf(value, size, "Not Jailed\n");
+	} else {
+		err = snprintf(value, size,
+			"IPv4: %s\nIPv6: %s\n"
+			"max_nrtask %d current nrtask %d max_timeslice %lu "
+			"nice %lu\n"
+			"max_memlock %lu max_data %lu\n",
+			tsec->ip4_addr_name ? tsec->ip4_addr_name : "(none)",
+			tsec->ip6_addr_name ? tsec->ip6_addr_name : "(none)",
+			tsec->max_nrtask, tsec->cur_nrtask, tsec->maxtimeslice,
+			tsec->nice, tsec->max_data, tsec->max_memlock);
+	}
+
+	return err;
+}
+
+/*
+ * Forbid a process in a jail from sending a signal to a process in
another
+ * (or no) jail through file sigio.
+ *
+ * We consider the process which set the fowner to be the one sending
the
+ * signal, rather than the one writing to the file.  Therefore we store
the
+ * jail of a process during jail_file_set_fowner, then check that
against
+ * the jail of the process receiving the signal.
+ */
+static int
+jail_file_send_sigiotask(struct task_struct *tsk, struct fown_struct
*fown,
+       int sig)
+{
+	struct file *file;
+
+	if (!in_jail(current))
+		return 0;
+
+	file = container_of(fown, struct file, f_owner);
+	if (file->f_security[jail_idx] != tsk->security[jail_idx])
+		return -EPERM;
+
+	return 0;
+}
+
+static int
+jail_file_set_fowner(struct file *file)
+{
+	struct jail_struct *tsec;
+
+	tsec = current->security[jail_idx];
+	file->f_security[jail_idx] = tsec;
+	if (tsec)
+		kref_get(&tsec->kref);
+
+	return 0;
+}
+
+static void free_ipc_security(struct kern_ipc_perm *ipc)
+{
+	struct jail_struct *tsec;
+
+	tsec = ipc->security[jail_idx];
+	if (!tsec)
+		return;
+	kref_put(&tsec->kref, release_jail);
+	ipc->security[jail_idx] = NULL;
+}
+
+static void free_file_security(struct file *file)
+{
+	struct jail_struct *tsec;
+
+	tsec = file->f_security[jail_idx];
+	if (!tsec)
+		return;
+	kref_put(&tsec->kref, release_jail);
+	file->f_security[jail_idx] = NULL;
+}
+
+static void free_inode_security(struct inode *inode)
+{
+	struct jail_struct *tsec;
+
+	tsec = inode->i_security[jail_idx];
+	if (!tsec)
+		return;
+	kref_put(&tsec->kref, release_jail);
+	inode->i_security[jail_idx] = NULL;
+}
+
+/*
+ * LSM ptrace hook:
+ * process in jail may not ptrace process not in the same jail
+ */
+static int
+jail_ptrace (struct task_struct *tracer, struct task_struct *tracee)
+{
+	struct jail_struct *tsec = tracer->security[jail_idx];
+
+	if (tsec && (tsec->jail_flags & IN_USE)) {
+		if (tsec == tracee->security[jail_idx])
+			return 0;
+		return -EPERM;
+	}
+	return 0;
+}
+
+/*
+ * process in jail may only use one (aliased) ip address.  If they try
to
+ * attach to 127.0.0.1, that is remapped to their own address.  If some
+ * other address (and not their own), deny permission
+ */
+static int jail_socket_unix_bind(struct socket *sock, struct sockaddr
*address,
+		int addrlen);
+
+#define loopbackaddr htonl((127 << 24) | 1)
+
+static inline int jail_inet4_bind(struct socket *sock, struct sockaddr
*address,
+	int addrlen, struct jail_struct *tsec)
+{
+	struct sockaddr_in *inaddr;
+	__u32 sin_addr, jailaddr;
+
+	if (!(tsec->jail_flags & GOT_IPV4))
+		return -EPERM;
+
+	inaddr = (struct sockaddr_in *) address;
+	sin_addr = inaddr->sin_addr.s_addr;
+	jailaddr = tsec->addr4;
+
+	if (sin_addr == jailaddr)
+		return 0;
+
+	if (sin_addr == loopbackaddr || !sin_addr) {
+		bsdj_debug(DBG, "Got a loopback or 0 address\n");
+		sin_addr = jailaddr;
+		bsdj_debug(DBG, "Converted to: %u.%u.%u.%u\n",
+			NIPQUAD(sin_addr));
+		return 0;
+	}
+
+	return -EPERM;
+}
+
+static inline int
+jail_inet6_bind(struct socket *sock, struct sockaddr *address, int
addrlen,
+	struct jail_struct *tsec)
+{
+	struct sockaddr_in6 *inaddr6;
+	struct in6_addr *sin6_addr, *jailaddr;
+
+	if (!(tsec->jail_flags & GOT_IPV6))
+		return -EPERM;
+
+	inaddr6 = (struct sockaddr_in6 *) address;
+	sin6_addr = &inaddr6->sin6_addr;
+	jailaddr = &tsec->addr6;
+
+	if (ipv6_addr_cmp(jailaddr, sin6_addr) == 0)
+		return 0;
+
+	if (ipv6_addr_cmp(sin6_addr, &in6addr_loopback) == 0) {
+		ipv6_addr_copy(sin6_addr, jailaddr);
+		return 0;
+	}
+
+	printk(KERN_NOTICE "%s: DENYING\n", __FUNCTION__);
+	printk(KERN_NOTICE "%s: a %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x "
+		"j %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
+		__FUNCTION__,
+		NIP6(*sin6_addr),
+		NIP6(*jailaddr));
+
+	return -EPERM;
+}
+
+static int
+jail_socket_bind(struct socket *sock, struct sockaddr *address, int
addrlen)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	if (sock->sk->sk_family == AF_UNIX)
+		return jail_socket_unix_bind(sock, address, addrlen);
+
+	if (!(tsec->jail_flags & (GOT_IPV4 | GOT_IPV6)))
+		/* If we want to be strict, we could just
+		 * deny net access when lacking a pseudo ip.
+		 * For now we just allow it. */
+		return 0;
+
+	switch(address->sa_family) {
+		case AF_INET:
+			return jail_inet4_bind(sock, address, addrlen, tsec);
+
+		case AF_INET6:
+			return jail_inet6_bind(sock, address, addrlen, tsec);
+
+		default:
+			return 0;
+	}
+}
+
+/*
+ * If locked in an ipv6 jail, don't let them use ipv4, and vice versa
+ */
+static int
+jail_socket_create(int family, int type, int protocol, int kern)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || kern || !(tsec->jail_flags & IN_USE) ||
+			!(tsec->jail_flags & (GOT_IPV4 | GOT_IPV6)))
+		return 0;
+
+	switch(family) {
+		case AF_INET:
+			if (tsec->jail_flags & GOT_IPV4)
+				return 0;
+			return -EPERM;
+		case AF_INET6:
+			if (tsec->jail_flags & GOT_IPV6)
+				return 0;
+			return -EPERM;
+		default:
+			return 0;
+	};
+
+	return 0;
+}
+
+static void
+jail_socket_post_create(struct socket *sock, int family, int type,
+	int protocol, int kern)
+{
+	struct inet_opt *inet;
+	struct ipv6_pinfo *inet6;
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || kern || !(tsec->jail_flags & IN_USE) ||
+			!(tsec->jail_flags & (GOT_IPV4 | GOT_IPV6)))
+		return;
+
+	switch(family) {
+		case AF_INET:
+			inet = inet_sk(sock->sk);
+			inet->saddr = tsec->addr4;
+			break;
+		case AF_INET6:
+			inet6 = inet6_sk(sock->sk);
+			ipv6_addr_copy(&inet6->saddr, &tsec->addr6);
+			break;
+		default:
+			break;
+	};
+
+	return;
+}
+
+static int
+jail_socket_listen(struct socket *sock, int backlog)
+{
+	struct inet_opt *inet;
+	struct ipv6_pinfo *inet6;
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE) ||
+			!(tsec->jail_flags & (GOT_IPV4 | GOT_IPV6)))
+		return 0;
+
+	switch (sock->sk->sk_family) {
+		case AF_INET:
+			inet = inet_sk(sock->sk);
+			if (inet->saddr == tsec->addr4)
+				return 0;
+			return -EPERM;
+
+		case AF_INET6:
+			inet6 = inet6_sk(sock->sk);
+			if (ipv6_addr_cmp(&inet6->saddr, &tsec->addr6) == 0)
+				return 0;
+			return -EPERM;
+
+		default:
+			return 0;
+
+	}
+}
+
+static void free_sock_security(struct sock *sk)
+{
+	struct jail_struct *tsec;
+
+	tsec = sk->sk_security[jail_idx];
+	if (!tsec)
+		return;
+	kref_put(&tsec->kref, release_jail);
+	sk->sk_security[jail_idx] = NULL;
+}
+
+/*
+ * The next three (socket) hooks prevent a process in a jail from
sending
+ * data to a abstract unix domain socket which was bound outside the
jail.
+ */
+static int
+jail_socket_unix_bind(struct socket *sock, struct sockaddr *address,
+	int addrlen)
+{
+	struct sockaddr_un *sunaddr;
+	struct jail_struct *tsec;
+
+	if (sock->sk->sk_family != AF_UNIX)
+		return 0;
+
+	sunaddr = (struct sockaddr_un *) address;
+	if (sunaddr->sun_path[0] != 0)
+		return 0;
+
+	tsec = current->security[jail_idx];
+	sock->sk->sk_security[jail_idx] = tsec;
+	if (tsec)
+		kref_get(&tsec->kref);
+	return 0;
+}
+
+/*
+ * Note - we deny sends  both from unjailed to jailed, and from jailed
+ * to unjailed.  As well as, of course between different jails.
+ */
+static int
+jail_socket_unix_may_send(struct socket *sock, struct socket *other)
+{
+	struct jail_struct *tsec, *ssec;
+
+	tsec = current->security[jail_idx];  /* jail of sending process */
+	ssec = other->sk->sk_security[jail_idx];  /* jail of receiver */
+
+	if (tsec != ssec)
+		return -EPERM;
+
+	return 0;
+}
+
+static int
+jail_socket_unix_stream_connect(struct socket *sock,
+	      struct socket *other, struct sock *newsk)
+{
+	struct jail_struct *tsec, *ssec;
+
+	tsec = current->security[jail_idx];  /* jail of sending process */
+	ssec = other->sk->sk_security[jail_idx];  /* jail of receiver */
+
+	if (tsec != ssec)
+		return -EPERM;
+
+	return 0;
+}
+
+static int
+jail_mount(char * dev_name, struct nameidata *nd, char * type,
+                         unsigned long flags, void * data)
+{
+	if (in_jail(current))
+		return -EPERM;
+
+	return 0;
+}
+
+static int
+jail_umount(struct vfsmount *mnt, int flags)
+{
+	if (in_jail(current))
+		return -EPERM;
+
+	return 0;
+}
+
+/*
+ * process in jail may not:
+ *   use nice
+ *   change network config
+ *   load/unload modules
+ */
+static int
+jail_capable (struct task_struct *tsk, int cap)
+{
+	if (in_jail(tsk)) {
+		if (cap == CAP_SYS_NICE)
+			return -EPERM;
+		if (cap == CAP_NET_ADMIN)
+			return -EPERM;
+		if (cap == CAP_SYS_MODULE)
+			return -EPERM;
+		if (cap == CAP_SYS_RAWIO)
+			return -EPERM;
+	}
+
+	if (cap_is_fs_cap (cap) ? tsk->fsuid == 0 : tsk->euid == 0)
+		return 0;
+	return -EPERM;
+}
+
+/*
+ * jail_security_task_create:
+ *
+ * If the current process is ina a jail, and that jail is about to
exceed a
+ * maximum number of processes, then refuse to fork.  If the maximum
number
+ * of jails is listed as 0, then there is no limit for this jail, and
we allow
+ * all forks.
+ */
+static inline int
+jail_security_task_create (unsigned long clone_flags)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	if (tsec->max_nrtask && tsec->cur_nrtask >= tsec->max_nrtask)
+		return -EPERM;
+	return 0;
+}
+
+/*
+ * The child of a process in a jail belongs in the same jail
+ */
+static int
+jail_task_alloc_security(struct task_struct *tsk)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	tsk->security[jail_idx] = tsec;
+	kref_get(&tsec->kref);
+	tsec->cur_nrtask++;
+	if (tsec->maxtimeslice) {
+		tsk->signal->rlim[RLIMIT_CPU].rlim_max = tsec->maxtimeslice;
+		tsk->signal->rlim[RLIMIT_CPU].rlim_cur = tsec->maxtimeslice;
+	}
+	if (tsec->max_data) {
+		tsk->signal->rlim[RLIMIT_CPU].rlim_max = tsec->max_data;
+		tsk->signal->rlim[RLIMIT_CPU].rlim_cur = tsec->max_data;
+	}
+	if (tsec->max_memlock) {
+		tsk->signal->rlim[RLIMIT_CPU].rlim_max = tsec->max_memlock;
+		tsk->signal->rlim[RLIMIT_CPU].rlim_cur = tsec->max_memlock;
+	}
+	if (tsec->nice)
+		set_user_nice(current, tsec->nice);
+
+	return 0;
+}
+
+static int
+jail_bprm_alloc_security(struct linux_binprm *bprm)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+	int ret;
+
+	if (!tsec)
+		return 0;
+
+	if (tsec->jail_flags & IN_USE)
+		return 0;
+
+	ret = enable_jail(current);
+	if (ret) {
+		/* if we failed, nix out the ip requests */
+		jail_task_free_security(current);
+		return ret;
+	}
+	return 0;
+}
+
+/*
+ * Process in jail may not create devices
+ * Thanks to Brad Spender for pointing out fifos should be allowed.
+ */
+/* TODO: We may want to allow /dev/log, at least... */
+static int
+jail_inode_mknod(struct inode *dir, struct dentry *dentry, int mode,
dev_t dev)
+{
+	if (!in_jail(current))
+		return 0;
+
+	if (S_ISFIFO(mode))
+		return 0;
+
+	return -EPERM;
+}
+
+/* yanked from fs/proc/base.c */
+static unsigned name_to_int(struct dentry *dentry)
+{
+	const char *name = dentry->d_name.name;
+	int len = dentry->d_name.len;
+	unsigned n = 0;
+
+	if (len > 1 && *name == '0')
+		goto out;
+	while (len-- > 0) {
+		unsigned c = *name++ - '0';
+		if (c > 9)
+			goto out;
+		if (n >= (~0U-9)/10)
+			goto out;
+		n *= 10;
+		n += c;
+	}
+	return n;
+out:
+	return ~0U;
+}
+
+/*
+ * jail_proc_inode_permission:
+ *   called only when current is in a jail, and is trying to reach
+ *   /proc/<pid>.  We check whether <pid> is in the same jail as
+ *   current.  If not, permission is denied.
+ *
+ * NOTE:  On the one hand, the task_to_inode(inode)->i_security
+ * approach seems cleaner, but on the other, this prevents us
+ * from unloading bsdjail for awhile...
+ */
+static int
+jail_proc_inode_permission(struct inode *inode, int mask,
+				    struct nameidata *nd)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+	struct dentry *dentry = nd->dentry;
+	unsigned pid;
+
+	pid = name_to_int(dentry);
+	if (pid == ~0U) {
+		return 0;
+	}
+
+	if (dentry->d_parent != dentry->d_sb->s_root)
+		return 0;
+	if (inode->i_security[jail_idx] != tsec)
+		return -ENOENT;
+
+	return 0;
+}
+
+/*
+ * A process in a jail may not see that /proc/<pid> exists for
+ * process not in its jail
+ * Unfortunately we can't pretend that pid for the starting process
+ * is 1, as vserver does.
+ */
+static int jail_task_lookup(struct task_struct *p)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec)
+		return 0;
+	if (tsec == p->security[jail_idx])
+		return 0;
+	return -EPERM;
+}
+/*
+ * security_task_to_inode:
+ * Set inode->security = task's jail.
+ */
+static void jail_task_to_inode(struct task_struct *p, struct inode
*inode)
+{
+	struct jail_struct *tsec = p->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return;
+	if (inode->i_security[jail_idx])
+		return;
+	kref_get(&tsec->kref);
+	inode->i_security[jail_idx] = tsec;
+}
+
+/*
+ * inode_permission:
+ * If we are trying to look into certain /proc files from in a jail, we
+ * 	may deny permission.
+ */
+static int
+jail_inode_permission(struct inode *inode, int mask,
+				    struct nameidata *nd)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	if (!nd)
+		return 0;
+
+	if (nd->dentry &&
+		strcmp(nd->dentry->d_sb->s_type->name, "proc") == 0) {
+		return jail_proc_inode_permission(inode, mask, nd);
+
+	}
+
+	return 0;
+}
+
+/*
+ * A function which returns -ENOENT if dentry is the dentry for
+ * a /proc/<pid> directory.  It returns 0 otherwise.
+ */
+static inline int
+generic_procpid_check(struct dentry *dentry)
+{
+	struct jail_struct *jail = current->security[jail_idx];
+	unsigned pid = name_to_int(dentry);
+
+	if (!jail || !(jail->jail_flags & IN_USE))
+		return 0;
+	if (pid == ~0U)
+		return 0;
+	if (strcmp(dentry->d_sb->s_type->name, "proc") != 0)
+		return 0;
+	if (dentry->d_parent != dentry->d_sb->s_root)
+		return 0;
+	if (dentry->d_inode->i_security[jail_idx] != jail)
+		return -ENOENT;
+	return 0;
+}
+
+/*
+ * We want getattr to fail on /proc/<pid> to prevent leakage through,
for
+ * instance, ls -d.
+ */
+static int
+jail_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
+{
+	return generic_procpid_check(dentry);
+}
+
+/* This probably is not necessary - /proc does not support xattrs? */
+static int
+jail_inode_getxattr(struct dentry *dentry, char *name)
+{
+	return generic_procpid_check(dentry);
+}
+
+/* process in jail may not send signal to process not in the same jail
*/
+static int
+jail_task_kill(struct task_struct *p, struct siginfo *info, int sig)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	if (tsec == p->security[jail_idx])
+		return 0;
+
+	if (sig==SIGCHLD)
+		return 0;
+
+	return -EPERM;
+}
+
+/*
+ * LSM hooks to limit jailed process' abilities to muck with resource
+ * limits
+ */
+static int jail_task_setrlimit (unsigned int resource, struct rlimit
*new_rlim)
+{
+	if (!in_jail(current))
+		return 0;
+
+	return -EPERM;
+}
+
+static int jail_task_setscheduler (struct task_struct *p, int policy,
+				    struct sched_param *lp)
+{
+	if (!in_jail(current))
+		return 0;
+
+	return -EPERM;
+}
+
+/*
+ * LSM hooks to limit IPC access.
+ */
+
+static inline int
+basic_ipc_security_check(struct kern_ipc_perm *p, struct task_struct
*target)
+{
+	struct jail_struct *tsec = target->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+
+	if (p->security[jail_idx] != tsec)
+		return -EPERM;
+
+	return 0;
+}
+
+static int
+jail_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
+{
+	return basic_ipc_security_check(ipcp, current);
+}
+
+static int
+jail_shm_alloc_security (struct shmid_kernel *shp)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+	shp->shm_perm.security[jail_idx] = tsec;
+	kref_get(&tsec->kref);
+	return 0;
+}
+
+static void
+jail_shm_free_security (struct shmid_kernel *shp)
+{
+	free_ipc_security(&shp->shm_perm);
+}
+
+static int
+jail_shm_associate (struct shmid_kernel *shp, int shmflg)
+{
+	return basic_ipc_security_check(&shp->shm_perm, current);
+}
+
+static int
+jail_shm_shmctl(struct shmid_kernel *shp, int cmd)
+{
+	if (cmd == IPC_INFO || cmd == SHM_INFO)
+		return 0;
+
+	return basic_ipc_security_check(&shp->shm_perm, current);
+}
+
+static int
+jail_shm_shmat(struct shmid_kernel *shp, char *shmaddr, int shmflg)
+{
+	return basic_ipc_security_check(&shp->shm_perm, current);
+}
+
+static int
+jail_msg_queue_alloc(struct msg_queue *msq)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+	msq->q_perm.security[jail_idx] = tsec;
+	kref_get(&tsec->kref);
+	return 0;
+}
+
+static void
+jail_msg_queue_free(struct msg_queue *msq)
+{
+	free_ipc_security(&msq->q_perm);
+}
+
+static int jail_msg_queue_associate(struct msg_queue *msq, int flag)
+{
+	return basic_ipc_security_check(&msq->q_perm, current);
+}
+
+static int
+jail_msg_queue_msgctl(struct msg_queue *msq, int cmd)
+{
+	if (cmd == IPC_INFO || cmd == MSG_INFO)
+		return 0;
+
+	return basic_ipc_security_check(&msq->q_perm, current);
+}
+
+static int
+jail_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg, int
msqflg)
+{
+	return basic_ipc_security_check(&msq->q_perm, current);
+}
+
+static int
+jail_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
+		struct task_struct *target, long type, int mode)
+
+{
+	return basic_ipc_security_check(&msq->q_perm, target);
+}
+
+static int
+jail_sem_alloc_security(struct sem_array *sma)
+{
+	struct jail_struct *tsec = current->security[jail_idx];
+
+	if (!tsec || !(tsec->jail_flags & IN_USE))
+		return 0;
+	sma->sem_perm.security[jail_idx] = tsec;
+	kref_get(&tsec->kref);
+	return 0;
+}
+
+static void
+jail_sem_free_security(struct sem_array *sma)
+{
+	free_ipc_security(&sma->sem_perm);
+}
+
+static int
+jail_sem_associate(struct sem_array *sma, int semflg)
+{
+	return basic_ipc_security_check(&sma->sem_perm, current);
+}
+
+static int
+jail_sem_semctl(struct sem_array *sma, int cmd)
+{
+	if (cmd == IPC_INFO || cmd == SEM_INFO)
+		return 0;
+	return basic_ipc_security_check(&sma->sem_perm, current);
+}
+
+static int
+jail_sem_semop(struct sem_array *sma, struct sembuf *sops, unsigned
nsops,
+	int alter)
+{
+	return basic_ipc_security_check(&sma->sem_perm, current);
+}
+
+static int
+jail_sysctl(struct ctl_table *table, int op)
+{
+	if (!in_jail(current))
+		return 0;
+
+	if (op & 002)
+		return -EPERM;
+
+	return 0;
+}
+
+static struct security_operations bsdjail_security_ops = {
+	.ptrace  =			jail_ptrace,
+	.capable =			jail_capable,
+
+	.task_kill =			jail_task_kill,
+	.task_alloc_security =		jail_task_alloc_security,
+	.task_free_security =		jail_task_free_security,
+	.bprm_alloc_security =		jail_bprm_alloc_security,
+	.task_create =			jail_security_task_create,
+	.task_to_inode =		jail_task_to_inode,
+	.task_lookup =			jail_task_lookup,
+
+	.task_setrlimit =		jail_task_setrlimit,
+	.task_setscheduler =		jail_task_setscheduler,
+
+	.setprocattr =                  jail_setprocattr,
+	.getprocattr =                  jail_getprocattr,
+
+	.file_set_fowner =		jail_file_set_fowner,
+	.file_send_sigiotask =		jail_file_send_sigiotask,
+	.file_free_security =		free_file_security,
+
+	.socket_bind =			jail_socket_bind,
+	.socket_listen =		jail_socket_listen,
+	.socket_create =		jail_socket_create,
+	.socket_post_create =		jail_socket_post_create,
+        .unix_stream_connect =		jail_socket_unix_stream_connect,
+	.unix_may_send =		jail_socket_unix_may_send,
+	.sk_free_security =		free_sock_security,
+
+	.inode_mknod =			jail_inode_mknod,
+	.inode_permission =		jail_inode_permission,
+	.inode_free_security =		free_inode_security,
+	.inode_getattr =		jail_inode_getattr,
+	.inode_getxattr =		jail_inode_getxattr,
+	.sb_mount =			jail_mount,
+	.sb_umount =			jail_umount,
+
+	.ipc_permission =		jail_ipc_permission,
+	.shm_alloc_security = 		jail_shm_alloc_security,
+	.shm_free_security = 		jail_shm_free_security,
+	.shm_associate =		jail_shm_associate,
+	.shm_shmctl =			jail_shm_shmctl,
+	.shm_shmat =			jail_shm_shmat,
+
+	.msg_queue_alloc_security =	jail_msg_queue_alloc,
+	.msg_queue_free_security =	jail_msg_queue_free,
+	.msg_queue_associate =		jail_msg_queue_associate,
+	.msg_queue_msgctl =		jail_msg_queue_msgctl,
+	.msg_queue_msgsnd =		jail_msg_queue_msgsnd,
+	.msg_queue_msgrcv =		jail_msg_queue_msgrcv,
+
+	.sem_alloc_security = 		jail_sem_alloc_security,
+	.sem_free_security =  		jail_sem_free_security,
+	.sem_associate =		jail_sem_associate,
+	.sem_semctl =			jail_sem_semctl,
+	.sem_semop =			jail_sem_semop,
+
+	.sysctl =			jail_sysctl,
+};
+
+static int __init bsdjail_init (void)
+{
+	if (register_security (&bsdjail_security_ops)) {
+		printk (KERN_INFO
+			"Failure registering BSD Jail module with the kernel\n");
+
+		jail_idx = mod_reg_security(MY_NAME, &bsdjail_security_ops);
+		if (jail_idx < 0) {
+			printk (KERN_INFO "Failure registering BSD Jail "
+				" module with primary security module.\n");
+			return -EINVAL;
+		}
+		secondary = 1;
+	}
+	printk (KERN_INFO "BSD Jail module initialized.\n");
+
+	return 0;
+}
+
+static void __exit bsdjail_exit (void)
+{
+	if (secondary) {
+		if (mod_unreg_security (MY_NAME, &bsdjail_security_ops))
+			printk (KERN_INFO "Failure unregistering BSD Jail "
+				" module with primary module.\n");
+	} else {
+		if (unregister_security (&bsdjail_security_ops)) {
+			printk (KERN_INFO "Failure unregistering BSD Jail "
+				"module with the kernel\n");
+		}
+	}
+
+	printk (KERN_INFO "BSD Jail module removed\n");
+}
+
+security_initcall (bsdjail_init);
+module_exit (bsdjail_exit);
+
+MODULE_DESCRIPTION("BSD Jail LSM.");
+MODULE_LICENSE("GPL");