From: Serge Hallyn Attached is a patch against the security Kconfig and Makefile to support bsdjail, as well as the bsdjail.c file itself. bsdjail offers functionality similar to (but more limited than) the vserver patch. A process in a jail lives under a chroot which is not vulnerable to the well-known chdir(...)(etc)chroot(.) attack against normal chroots, and may be locked to one ip address. For additional features, please see Documentation/bsdjail.txt, which is included in the next patch. Changelog: Sep 10, 2004: original version Sep 12, 2004: add ipv6 support Sep 13, 2004: support simultaneous ipv4+ipv6 Oct 6, 2004: move kref release function to kref_put from kref_init Signed-off-by: Serge E. Hallyn Signed-off-by: Andrew Morton --- 25-akpm/security/Kconfig | 11 25-akpm/security/Makefile | 1 25-akpm/security/bsdjail.c | 1525 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 1537 insertions(+) diff -puN /dev/null security/bsdjail.c --- /dev/null Thu Apr 11 07:25:15 2002 +++ 25-akpm/security/bsdjail.c Wed Oct 6 16:20:17 2004 @@ -0,0 +1,1525 @@ +/* + * 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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static int jail_debug = 0; +MODULE_PARM(jail_debug, "i"); +MODULE_PARM_DESC(jail_debug, "Print bsd jail debugging messages.\n"); + +#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 = 0; + +/* + * 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//attr/exec */ + char *root_pathname; /* char * containing path to use as jail / */ + 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 */ + + struct dentry *dentry; /* dentry of fs root */ + struct vfsmount *mnt; /* vfsmnt of fs root */ + + /* 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; +}; + +#define in_use(x) (x->jail_flags & IN_USE) +#define set_in_use(x) (x->jail_flags |= IN_USE) + +#define got_network(x) (x->jail_flags & (GOT_IPV4 | GOT_IPV6)) +#define got_ipv4(x) (x->jail_flags & (GOT_IPV4)) +#define got_ipv6(x) (x->jail_flags & (GOT_IPV6)) +#define set_ipv4(x) (x->jail_flags |= GOT_IPV4) +#define set_ipv6(x) (x->jail_flags |= GOT_IPV6) +#define unset_got_ipv4(x) (x->jail_flags &= ~GOT_IPV4) +#define unset_got_ipv6(x) (x->jail_flags &= ~GOT_IPV6) + +/* + * structs, defines, and functions to cope with stacking + */ + +#define get_task_security(task) (task->security) +#define get_inode_security(inode) (inode->i_security) +#define get_sock_security(sock) (sock->sk_security) +#define get_file_security(file) (file->f_security) +#define get_ipc_security(ipc) (ipc->security) + +#define jail_of(proc) (get_task_security(proc)) + +/* + * 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) +{ + dput(tsec->dentry); + mntput(tsec->mnt); + module_put(THIS_MODULE); +} + + +static void free_jail(struct jail_struct *tsec) +{ + if (!tsec) + return; + + if (tsec->root_pathname) + kfree(tsec->root_pathname); + if (tsec->ip4_addr_name) + kfree(tsec->ip4_addr_name); + if (tsec->ip6_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); +} + +#define set_task_security(task,data) task->security = data +#define set_inode_security(inode,data) inode->i_security = data +#define set_sock_security(sock,data) sock->sk_security = data +#define set_file_security(file,data) file->f_security = data +#define set_ipc_security(ipc,data) ipc.security = data + +/* + * 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; + + tsec = get_task_security(task); + + if (!tsec) + return; + + if (!in_use(tsec)) { + /* + * someone did 'echo -n x > /proc//attr/exec' but + * then forked before execing. Nuke the old info. + */ + free_jail(tsec); + set_task_security(task,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) + return ERR_PTR(-ENOMEM); + memset(tsec, 0, sizeof(struct jail_struct)); + set_task_security(tsk, tsec); + return tsec; +} + +static inline int +in_jail(struct task_struct *t) +{ + struct jail_struct *tsec = jail_of(t); + + if (tsec && in_use(tsec)) + return 1; + + return 0; +} + +/* + * If a network address was passed into /proc//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]; + + unset_got_ipv4(tsec); + tsec->addr4 = 0; + unset_got_ipv6(tsec); + 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); + set_ipv4(tsec); + 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]); + } + set_ipv6(tsec); + 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 + * Sets process root+pwd + * Stores the requested ip address + * Registers a unique pseudo-proc filesystem for this jail + */ +static int enable_jail(struct task_struct *tsk) +{ + struct nameidata nd; + struct jail_struct *tsec; + int retval = -EFAULT; + + tsec = jail_of(tsk); + if (!tsec || !tsec->root_pathname) + goto out; + + /* + * USE_JAIL_NAMESPACE: could be useful, so that future mounts outside + * the jail don't affect the jail. But it's not necessary, and + * requires exporting copy_namespace from fs/namespace.c + * + * Actually, it would also be useful for truly hiding + * information about mounts which do not exist in this jail. +#define USE_JAIL_NAMESPACE + */ +#ifdef USE_JAIL_NAMESPACE + bsdj_debug(DBG, "bsdjail: copying namespace.\n"); + retval = -EPERM; + if (copy_namespace(CLONE_NEWNS, tsk)) + goto out; + bsdj_debug(DBG, "bsdjail: copied namespace.\n"); +#endif + + /* find our new root directory */ + bsdj_debug(DBG, "bsdjail: looking up %s\n", tsec->root_pathname); + retval = path_lookup(tsec->root_pathname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd); + if (retval) + goto out; + + bsdj_debug(DBG, "bsdjail: got %s, setting root to it\n", tsec->root_pathname); + + /* and set the fsroot to it */ + set_fs_root(tsk->fs, nd.mnt, nd.dentry); + set_fs_pwd(tsk->fs, nd.mnt, nd.dentry); + + bsdj_debug(DBG, "bsdjail: root has been set. Have fun.\n"); + + /* 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->rlim[RLIMIT_DATA].rlim_cur = tsec->max_data; + current->rlim[RLIMIT_DATA].rlim_max = tsec->max_data; + } + if (tsec->max_memlock) { + current->rlim[RLIMIT_MEMLOCK].rlim_cur = tsec->max_memlock; + current->rlim[RLIMIT_MEMLOCK].rlim_max = tsec->max_memlock; + } + if (tsec->maxtimeslice) { + current->rlim[RLIMIT_CPU].rlim_cur = tsec->maxtimeslice; + current->rlim[RLIMIT_CPU].rlim_max = tsec->maxtimeslice; + } + /* success and end */ + tsec->mnt = mntget(nd.mnt); + tsec->dentry = dget(nd.dentry); + path_release(&nd); + kref_init(&tsec->kref); + set_in_use(tsec); + + /* won't let ourselves be removed until this jail goes away */ + try_module_get(THIS_MODULE); + + return 0; + +out: + return retval; +} + +/* + * LSM /proc//attr hooks. + * You may write into /proc//attr/exec: + * root /some/path + * ip 2.2.2.2 + * 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 size) +{ + struct jail_struct *tsec = jail_of(current); + long val; + int start, len; + + if (tsec && in_use(tsec)) + return -EINVAL; /* let them guess why */ + + if (p != current || strcmp(name, "exec")) + return -EPERM; + + if (strncmp(value, "root ", 5)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + if (tsec->root_pathname) + kfree(tsec->root_pathname); + start = 5; + len = size-start; + tsec->root_pathname = kmalloc(len+1, GFP_KERNEL); + if (!tsec->root_pathname) + return -ENOMEM; + strlcpy(tsec->root_pathname, value+start, len+1); + } else if (strncmp(value, "ip ", 3)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + if (tsec->ip4_addr_name) + kfree(tsec->ip4_addr_name); + start = 3; + len = size-start; + tsec->ip4_addr_name = kmalloc(len+1, GFP_KERNEL); + if (!tsec->ip4_addr_name) + return -ENOMEM; + strlcpy(tsec->ip4_addr_name, value+start, len+1); + } else if (strncmp(value, "ip6 ", 4) == 0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + if (tsec->ip6_addr_name) + kfree(tsec->ip6_addr_name); + start = 4; + len = size-start; + tsec->ip6_addr_name = kmalloc(len+1, GFP_KERNEL); + if (!tsec->ip6_addr_name) + return -ENOMEM; + strlcpy(tsec->ip6_addr_name, value+start, len+1); + + /* the next two are equivalent */ + } else if (strncmp(value, "slice ", 6)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = simple_strtoul(value+6, NULL, 0); + tsec->maxtimeslice = val; + } else if (strncmp(value, "timeslice ", 10)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = simple_strtoul(value+10, NULL, 0); + tsec->maxtimeslice = val; + } else if (strncmp(value, "nrtask ", 7)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = (int) simple_strtol(value+7, NULL, 0); + if (val < 1) + return -EINVAL; + tsec->max_nrtask = val; + } else if (strncmp(value, "memlock ", 8)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = simple_strtoul(value+8, NULL, 0); + tsec->max_memlock = val; + } else if (strncmp(value, "data ", 5)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = simple_strtoul(value+5, NULL, 0); + tsec->max_data = val; + } else if (strncmp(value, "nice ", 5)==0) { + if (!tsec) + tsec = alloc_task_security(current); + if (IS_ERR(tsec)) + return -ENOMEM; + + val = simple_strtoul(value+5, NULL, 0); + tsec->nice = val; + } else + return -EINVAL; + + return size; +} + +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//attr read hook. + * + * /proc/$$/attr/current output: + * If the reading process, say process 1001, is in a jail, then + * cat /proc/999/attr/current + * will print networking information. + * If the reading process, say process 1001, is not in a jail, then + * cat /proc/999/attr/current + * will return + * root: (root of jail) + * ip: (ip address of jail) + * if 999 is in a jail, or + * -EINVAL + * if 999 is not in a jail. + * + * /proc/$$/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(jail_of(current), 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" + "root \n" + "ip \n" + "ip6 \n" + "nrtask \n" + "nice \n" + "slice \n" + "data \n" + "memlock \n"); + return err; + } + + if (strcmp(name, "current")) + return -EPERM; + + tsec = jail_of(p); + if (!tsec || !in_use(tsec)) { + err = snprintf(value, size, "Not Jailed\n"); + } else { + err = snprintf(value, size, + "Root: %s\nIPv4: %s\nIPv6: %s\n" + "max_nrtask %d current nrtask %d max_timeslice %lu " + "nice %lu\n" + "max_memlock %lu max_data %lu\n", + tsec->root_pathname, + 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 fd, int reason) +{ + struct file *file; + struct jail_struct *tsec, *fsec; + + if (!in_jail(current)) + return 0; + + file = (struct file *)((long)fown - offsetof(struct file,f_owner)); + tsec = jail_of(tsk); + fsec = get_file_security(file); + + if (fsec != tsec) + return -EPERM; + + return 0; +} + +static int +jail_file_set_fowner(struct file *file) +{ + struct jail_struct *tsec; + + tsec = jail_of(current); + set_file_security(file, tsec); + if (tsec) + kref_get(&tsec->kref); + + return 0; +} + +static void free_ipc_security(struct kern_ipc_perm *ipc) +{ + struct jail_struct *tsec; + + tsec = get_ipc_security(ipc); + if (!tsec) + return; + kref_put(&tsec->kref, release_jail); + set_ipc_security((*ipc), NULL); +} + +static void free_file_security(struct file *file) +{ + struct jail_struct *tsec; + + tsec = get_file_security(file); + if (!tsec) + return; + kref_put(&tsec->kref, release_jail); + set_file_security(file, NULL); +} + +static void free_inode_security(struct inode *inode) +{ + struct jail_struct *tsec; + + tsec = get_inode_security(inode); + if (!tsec) + return; + kref_put(&tsec->kref, release_jail); + set_inode_security(inode, 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 = jail_of(tracer); + + if (tsec && in_use(tsec)) { + if (tsec == jail_of(tracee)) + 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 (!got_ipv4(tsec)) + 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 (!got_ipv6(tsec)) + 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + + if (sock->sk->sk_family == AF_UNIX) + return jail_socket_unix_bind(sock, address, addrlen); + + if (!got_network(tsec)) + /* 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 = jail_of(current); + + if (!tsec || !in_use(tsec) || kern || !got_network(tsec)) + return 0; + + switch(family) { + case AF_INET: + if (got_ipv4(tsec)) + return 0; + return -EPERM; + case AF_INET6: + if (got_ipv6(tsec)) + 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 = jail_of(current); + + if (!tsec || !in_use(tsec) || kern || !got_network(tsec)) + 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 = jail_of(current); + + if (!tsec || !in_use(tsec) || !got_network(tsec)) + 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 = get_sock_security(sk); + if (!tsec) + return; + kref_put(&tsec->kref, release_jail); + set_sock_security(sk, 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 = jail_of(current); + set_sock_security(sock->sk, 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 = jail_of(current); /* jail of sending process */ + ssec = get_sock_security(other->sk); /* 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 = jail_of(current); /* jail of sending process */ + ssec = get_sock_security(other->sk); /* 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + + set_task_security(tsk, tsec); + kref_get(&tsec->kref); + tsec->cur_nrtask++; + if (tsec->maxtimeslice) { + tsk->rlim[RLIMIT_CPU].rlim_max = tsec->maxtimeslice; + tsk->rlim[RLIMIT_CPU].rlim_cur = tsec->maxtimeslice; + } + if (tsec->max_data) { + tsk->rlim[RLIMIT_CPU].rlim_max = tsec->max_data; + tsk->rlim[RLIMIT_CPU].rlim_cur = tsec->max_data; + } + if (tsec->max_memlock) { + tsk->rlim[RLIMIT_CPU].rlim_max = tsec->max_memlock; + tsk->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; + int ret; + + tsec = jail_of(current); + if (!tsec) + return 0; + + if (in_use(tsec)) + return 0; + + if (tsec->root_pathname) { + ret = enable_jail(current); + if (ret) { + /* if we failed, nix out the root/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/. We check whether 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 = jail_of(current); + struct dentry *dentry = nd->dentry; + unsigned pid; + + pid = name_to_int(dentry); + if (pid == ~0U) { + struct qstr *dname = &dentry->d_name; + if (strcmp(dname->name, "scsi")==0 || + strcmp(dname->name, "sys")==0 || + strcmp(dname->name, "ide")==0) + return -EPERM; + return 0; + } + + if (dentry->d_parent != dentry->d_sb->s_root) + return 0; + if (get_inode_security(inode) != tsec) + return -ENOENT; + + return 0; +} + +/* + * Here is our attempt to prevent chroot escapes. + */ +static int +is_jailroot_parent(struct dentry *candidate, struct dentry *root, + struct vfsmount *rootmnt) +{ + if (candidate == root) + return 0; + + /* simple case: fs->root/.. == candidate */ + if (root->d_parent == candidate) + return 1; + + /* + * now more complicated: if fs->root is a mounted directory, + * then chdir(..) out of fs->root, at follow_dotdot, will follow + * the fs->root mount point. So we must check the parent dir of + * the fs->root mount point. + */ + if (rootmnt->mnt_root == root && rootmnt->mnt_mountpoint!=root) { + root = rootmnt->mnt_mountpoint; + rootmnt = rootmnt->mnt_parent; + return is_jailroot_parent(candidate, root, rootmnt); + } + + return 0; +} + +/* + * A process in a jail may not see that /proc/ 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 = jail_of(current); + + if (!tsec) + return 0; + if (tsec == jail_of(p)) + 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 = jail_of(p); + + if (!tsec || !in_use(tsec)) + return; + if (get_inode_security(inode)) + return; + kref_get(&tsec->kref); + set_inode_security(inode, tsec); +} + +/* + * inode_permission: + * If we are trying to look into certain /proc files from in a jail, we + * may deny permission. + * If we are trying to cd(..), but the cwd is the root of our jail, then + * permission is denied. + */ +static int +jail_inode_permission(struct inode *inode, int mask, + struct nameidata *nd) +{ + struct jail_struct *tsec = jail_of(current); + + if (!tsec || !in_use(tsec)) + 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); + + } + + if (!(mask&MAY_EXEC)) + return 0; + if (!inode || !S_ISDIR(inode->i_mode)) + return 0; + + if (is_jailroot_parent(nd->dentry, tsec->dentry, tsec->mnt)) { + bsdj_debug(WARN,"Attempt to chdir(..) out of jail!\n" + "(%s is a subdir of %s)\n", + tsec->dentry->d_name.name, + nd->dentry->d_name.name); + return -EPERM; + } + + return 0; +} + +/* + * A function which returns -ENOENT if dentry is the dentry for + * a /proc/ directory. It returns 0 otherwise. + */ +static inline int +generic_procpid_check(struct dentry *dentry) +{ + struct jail_struct *jail = jail_of(current); + unsigned pid = name_to_int(dentry); + + if (!jail || !in_use(jail)) + 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 (get_inode_security(dentry->d_inode) != jail) + return -ENOENT; + return 0; +} + +/* + * We want getattr to fail on /proc/ 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + + if (tsec == jail_of(p)) + 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 = jail_of(target); + + if (!tsec || !in_use(tsec)) + return 0; + + if (get_ipc_security(p) != 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + set_ipc_security(shp->shm_perm, 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + set_ipc_security(msq->q_perm, 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 = jail_of(current); + + if (!tsec || !in_use(tsec)) + return 0; + set_ipc_security(sma->sem_perm, 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 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, +}; + +static int __init bsdjail_init (void) +{ + int rc = 0; + + if (register_security (&bsdjail_security_ops)) { + printk (KERN_INFO + "Failure registering BSD Jail module with the kernel\n"); + + rc = mod_reg_security(MY_NAME, &bsdjail_security_ops); + if (rc < 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"); diff -puN security/Kconfig~lsm-add-bsdjail-module security/Kconfig --- 25/security/Kconfig~lsm-add-bsdjail-module Wed Oct 6 16:20:17 2004 +++ 25-akpm/security/Kconfig Wed Oct 6 16:20:17 2004 @@ -86,5 +86,16 @@ config SECURITY_SECLVL source security/selinux/Kconfig +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. + endmenu diff -puN security/Makefile~lsm-add-bsdjail-module security/Makefile --- 25/security/Makefile~lsm-add-bsdjail-module Wed Oct 6 16:20:17 2004 +++ 25-akpm/security/Makefile Wed Oct 6 16:20:17 2004 @@ -17,3 +17,4 @@ obj-$(CONFIG_SECURITY_SELINUX) += selin obj-$(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 _