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SubjectRe: [RFC] [PATCH] [2/3] LSM Stacking: stackable bsdjail (bsdjail lsm)
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Date
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");

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  Last update: 2005-03-22 14:07    [from the cache]
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