* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
- * Daniel Lezcano <dlezcano at fr.ibm.com>
+ * Daniel Lezcano <daniel.lezcano at free.fr>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#include "../config.h"
+#include "config.h"
+
#include <stdio.h>
#undef _GNU_SOURCE
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <termios.h>
-#include <namespace.h>
#include <sys/param.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
+#include <sys/socket.h>
#include <sys/prctl.h>
#include <sys/types.h>
-#include <sys/capability.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <sys/poll.h>
+#include <sys/syscall.h>
+
+#if HAVE_SYS_CAPABILITY_H
+#include <sys/capability.h>
+#endif
#ifdef HAVE_SYS_SIGNALFD_H
# include <sys/signalfd.h>
#include "af_unix.h"
#include "mainloop.h"
#include "utils.h"
-#include "utmp.h"
+#include "lxcutmp.h"
#include "monitor.h"
#include "commands.h"
#include "console.h"
#include "sync.h"
+#include "namespace.h"
+#include "apparmor.h"
+#include "lxcseccomp.h"
+#include "caps.h"
lxc_log_define(lxc_start, lxc);
-LXC_TTY_HANDLER(SIGINT);
-LXC_TTY_HANDLER(SIGQUIT);
-
static int match_fd(int fd)
{
return (fd == 0 || fd == 1 || fd == 2);
}
-int lxc_check_inherited(int fd_to_ignore)
+int lxc_check_inherited(struct lxc_conf *conf, int fd_to_ignore)
{
struct dirent dirent, *direntp;
int fd, fddir;
DIR *dir;
- int ret = 0;
+restart:
dir = opendir("/proc/self/fd");
if (!dir) {
WARN("failed to open directory: %m");
fddir = dirfd(dir);
while (!readdir_r(dir, &dirent, &direntp)) {
- char procpath[64];
- char path[PATH_MAX];
-
if (!direntp)
break;
if (match_fd(fd))
continue;
- /*
- * found inherited fd
- */
- ret = -1;
-
- snprintf(procpath, sizeof(procpath), "/proc/self/fd/%d", fd);
- if (readlink(procpath, path, sizeof(path)) == -1)
- ERROR("readlink(%s) failed : %m", procpath);
- else
- ERROR("inherited fd %d on %s", fd, path);
+ if (conf->close_all_fds) {
+ close(fd);
+ closedir(dir);
+ INFO("closed inherited fd %d", fd);
+ goto restart;
+ }
+ WARN("inherited fd %d", fd);
}
- if (closedir(dir))
- ERROR("failed to close directory");
- return ret;
+ closedir(dir); /* cannot fail */
+ return 0;
}
static int setup_signal_fd(sigset_t *oldmask)
struct lxc_answer answer;
int ret;
+ memset(&answer, 0, sizeof(answer));
answer.pid = handler->pid;
answer.ret = 0;
return 0;
}
+int lxc_cgroup_callback(int fd, struct lxc_request *request,
+ struct lxc_handler *handler)
+{
+ struct lxc_answer answer;
+ int ret;
+
+ memset(&answer, 0, sizeof(answer));
+ answer.pathlen = strlen(handler->cgroup) + 1;
+ answer.path = handler->cgroup;
+ answer.ret = 0;
+
+ ret = send(fd, &answer, sizeof(answer), 0);
+ if (ret < 0) {
+ WARN("failed to send answer to the peer");
+ return -1;
+ }
+
+ if (ret != sizeof(answer)) {
+ ERROR("partial answer sent");
+ return -1;
+ }
+
+ ret = send(fd, answer.path, answer.pathlen, 0);
+ if (ret < 0) {
+ WARN("failed to send answer to the peer");
+ return -1;
+ }
+
+ if (ret != answer.pathlen) {
+ ERROR("partial answer sent");
+ return -1;
+ }
+
+ return 0;
+}
+
+int lxc_clone_flags_callback(int fd, struct lxc_request *request,
+ struct lxc_handler *handler)
+{
+ struct lxc_answer answer;
+ int ret;
+
+ memset(&answer, 0, sizeof(answer));
+ answer.pid = 0;
+ answer.ret = handler->clone_flags;
+
+ ret = send(fd, &answer, sizeof(answer), 0);
+ if (ret < 0) {
+ WARN("failed to send answer to the peer");
+ return -1;
+ }
+
+ if (ret != sizeof(answer)) {
+ ERROR("partial answer sent");
+ return -1;
+ }
+
+ return 0;
+}
+
int lxc_set_state(const char *name, struct lxc_handler *handler, lxc_state_t state)
{
handler->state = state;
- lxc_monitor_send_state(name, state);
+ lxc_monitor_send_state(name, state, handler->lxcpath);
return 0;
}
goto out_mainloop_open;
}
- if (lxc_utmp_mainloop_add(&descr, handler)) {
- ERROR("failed to add utmp handler to mainloop");
- goto out_mainloop_open;
+ if (handler->conf->need_utmp_watch) {
+ #if HAVE_SYS_CAPABILITY_H
+ if (lxc_utmp_mainloop_add(&descr, handler)) {
+ ERROR("failed to add utmp handler to mainloop");
+ goto out_mainloop_open;
+ }
+ #else
+ DEBUG("not starting utmp handler as cap_sys_boot cannot be dropped without capabilities support\n");
+ #endif
}
return lxc_mainloop(&descr);
return -1;
}
-struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf)
+extern int lxc_caps_check(void);
+
+struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf, const char *lxcpath)
{
struct lxc_handler *handler;
+ if (!lxc_caps_check()) {
+ ERROR("Not running with sufficient privilege");
+ return NULL;
+ }
+
handler = malloc(sizeof(*handler));
if (!handler)
return NULL;
memset(handler, 0, sizeof(*handler));
handler->conf = conf;
+ handler->lxcpath = lxcpath;
+ apparmor_handler_init(handler);
handler->name = strdup(name);
if (!handler->name) {
ERROR("failed to allocate memory");
goto out_free;
}
+ if (lxc_command_init(name, handler, lxcpath))
+ goto out_free_name;
+
+ if (lxc_read_seccomp_config(conf) != 0) {
+ ERROR("failed loading seccomp policy");
+ goto out_close_maincmd_fd;
+ }
+
/* Begin the set the state to STARTING*/
if (lxc_set_state(name, handler, STARTING)) {
ERROR("failed to set state '%s'", lxc_state2str(STARTING));
goto out_free_name;
}
+ /* Start of environment variable setup for hooks */
+ if (setenv("LXC_NAME", name, 1)) {
+ SYSERROR("failed to set environment variable for container name");
+ }
+ if (setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
+ SYSERROR("failed to set environment variable for config path");
+ }
+ if (setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
+ SYSERROR("failed to set environment variable for rootfs mount");
+ }
+ if (setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
+ SYSERROR("failed to set environment variable for rootfs mount");
+ }
+ if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
+ SYSERROR("failed to set environment variable for console path");
+ }
+ if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
+ SYSERROR("failed to set environment variable for console log");
+ }
+ /* End of environment variable setup for hooks */
+
+ if (run_lxc_hooks(name, "pre-start", conf)) {
+ ERROR("failed to run pre-start hooks for container '%s'.", name);
+ goto out_aborting;
+ }
+
if (lxc_create_tty(name, conf)) {
ERROR("failed to create the ttys");
goto out_aborting;
lxc_delete_tty(&conf->tty_info);
out_aborting:
lxc_set_state(name, handler, ABORTING);
+out_close_maincmd_fd:
+ close(conf->maincmd_fd);
+ conf->maincmd_fd = -1;
out_free_name:
free(handler->name);
handler->name = NULL;
return NULL;
}
-void lxc_fini(const char *name, struct lxc_handler *handler)
+static void lxc_fini(const char *name, struct lxc_handler *handler)
{
/* The STOPPING state is there for future cleanup code
* which can take awhile
lxc_set_state(name, handler, STOPPING);
lxc_set_state(name, handler, STOPPED);
+ if (run_lxc_hooks(name, "post-stop", handler->conf))
+ ERROR("failed to run post-stop hooks for container '%s'.", name);
+
/* reset mask set by setup_signal_fd */
if (sigprocmask(SIG_SETMASK, &handler->oldmask, NULL))
WARN("failed to restore sigprocmask");
lxc_delete_console(&handler->conf->console);
lxc_delete_tty(&handler->conf->tty_info);
+ close(handler->conf->maincmd_fd);
+ handler->conf->maincmd_fd = -1;
free(handler->name);
+ if (handler->cgroup) {
+ lxc_cgroup_destroy(handler->cgroup);
+ free(handler->cgroup);
+ handler->cgroup = NULL;
+ }
free(handler);
}
kill(handler->pid, SIGKILL);
}
+#include <sys/reboot.h>
+#include <linux/reboot.h>
+
+/*
+ * reboot(LINUX_REBOOT_CMD_CAD_ON) will return -EINVAL
+ * in a child pid namespace if container reboot support exists.
+ * Otherwise, it will either succeed or return -EPERM.
+ */
+static int container_reboot_supported(void *arg)
+{
+ int *cmd = arg;
+ int ret;
+
+ ret = reboot(*cmd);
+ if (ret == -1 && errno == EINVAL)
+ return 1;
+ return 0;
+}
+
+static int must_drop_cap_sys_boot(void)
+{
+ FILE *f = fopen("/proc/sys/kernel/ctrl-alt-del", "r");
+ int ret, cmd, v;
+ long stack_size = 4096;
+ void *stack = alloca(stack_size) + stack_size;
+ int status;
+ pid_t pid;
+
+ if (!f) {
+ DEBUG("failed to open /proc/sys/kernel/ctrl-alt-del");
+ return 1;
+ }
+
+ ret = fscanf(f, "%d", &v);
+ fclose(f);
+ if (ret != 1) {
+ DEBUG("Failed to read /proc/sys/kernel/ctrl-alt-del");
+ return 1;
+ }
+ cmd = v ? LINUX_REBOOT_CMD_CAD_ON : LINUX_REBOOT_CMD_CAD_OFF;
+
+ pid = clone(container_reboot_supported, stack, CLONE_NEWPID | SIGCHLD, &cmd);
+ if (pid < 0) {
+ SYSERROR("failed to clone\n");
+ return -1;
+ }
+ if (wait(&status) < 0) {
+ SYSERROR("unexpected wait error: %m\n");
+ return -1;
+ }
+
+ if (WEXITSTATUS(status) != 1)
+ return 1;
+
+ return 0;
+}
+
static int do_start(void *data)
{
struct lxc_handler *handler = data;
lxc_sync_fini_parent(handler);
+ /* don't leak the pinfd to the container */
+ if (handler->pinfd >= 0)
+ close(handler->pinfd);
+
/* Tell the parent task it can begin to configure the
* container and wait for it to finish
*/
if (lxc_sync_barrier_parent(handler, LXC_SYNC_CONFIGURE))
return -1;
+ /*
+ * if we are in a new user namespace, become root there to have
+ * privilege over our namespace
+ */
+ if (!lxc_list_empty(&handler->conf->id_map)) {
+ NOTICE("switching to gid/uid 0 in new user namespace");
+ if (setgid(0)) {
+ SYSERROR("setgid");
+ goto out_warn_father;
+ }
+ if (setuid(0)) {
+ SYSERROR("setuid");
+ goto out_warn_father;
+ }
+ }
+
+ #if HAVE_SYS_CAPABILITY_H
+ if (handler->conf->need_utmp_watch) {
+ if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
+ SYSERROR("failed to remove CAP_SYS_BOOT capability");
+ goto out_warn_father;
+ }
+ DEBUG("Dropped cap_sys_boot\n");
+ }
+ #endif
+
/* Setup the container, ip, names, utsname, ... */
if (lxc_setup(handler->name, handler->conf)) {
ERROR("failed to setup the container");
goto out_warn_father;
}
- if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
- SYSERROR("failed to remove CAP_SYS_BOOT capability");
+ /* ask father to setup cgroups and wait for him to finish */
+ if (lxc_sync_barrier_parent(handler, LXC_SYNC_CGROUP))
return -1;
+
+ if (apparmor_load(handler) < 0)
+ goto out_warn_father;
+
+ if (lxc_seccomp_load(handler->conf) != 0)
+ goto out_warn_father;
+
+ if (run_lxc_hooks(handler->name, "start", handler->conf)) {
+ ERROR("failed to run start hooks for container '%s'.", handler->name);
+ goto out_warn_father;
+ }
+
+ /* The clearenv() and putenv() calls have been moved here
+ * to allow us to use enviroment variables passed to the various
+ * hooks, such as the start hook above. Not all of the
+ * variables like CONFIG_PATH or ROOTFS are valid in this
+ * context but others are. */
+ if (clearenv()) {
+ SYSERROR("failed to clear environment");
+ /* don't error out though */
+ }
+
+ if (putenv("container=lxc")) {
+ SYSERROR("failed to set environment variable");
+ goto out_warn_father;
}
close(handler->sigfd);
/* after this call, we are in error because this
* ops should not return as it execs */
- if (handler->ops->start(handler, handler->data))
- return -1;
+ handler->ops->start(handler, handler->data);
out_warn_father:
+ /* we want the parent to know something went wrong, so any
+ * value other than what it expects is ok. */
lxc_sync_wake_parent(handler, LXC_SYNC_POST_CONFIGURE);
return -1;
}
+int save_phys_nics(struct lxc_conf *conf)
+{
+ struct lxc_list *iterator;
+
+ lxc_list_for_each(iterator, &conf->network) {
+ struct lxc_netdev *netdev = iterator->elem;
+
+ if (netdev->type != LXC_NET_PHYS)
+ continue;
+ conf->saved_nics = realloc(conf->saved_nics,
+ (conf->num_savednics+1)*sizeof(struct saved_nic));
+ if (!conf->saved_nics) {
+ SYSERROR("failed to allocate memory");
+ return -1;
+ }
+ conf->saved_nics[conf->num_savednics].ifindex = netdev->ifindex;
+ conf->saved_nics[conf->num_savednics].orig_name = strdup(netdev->link);
+ if (!conf->saved_nics[conf->num_savednics].orig_name) {
+ SYSERROR("failed to allocate memory");
+ return -1;
+ }
+ INFO("stored saved_nic #%d idx %d name %s\n", conf->num_savednics,
+ conf->saved_nics[conf->num_savednics].ifindex,
+ conf->saved_nics[conf->num_savednics].orig_name);
+ conf->num_savednics++;
+ }
+
+ return 0;
+}
+
+
int lxc_spawn(struct lxc_handler *handler)
{
- int clone_flags;
int failed_before_rename = 0;
const char *name = handler->name;
if (lxc_sync_init(handler))
return -1;
- clone_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
+ handler->clone_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
+ if (!lxc_list_empty(&handler->conf->id_map)) {
+ INFO("Cloning a new user namespace");
+ handler->clone_flags |= CLONE_NEWUSER;
+ }
if (!lxc_list_empty(&handler->conf->network)) {
- clone_flags |= CLONE_NEWNET;
+ handler->clone_flags |= CLONE_NEWNET;
+
+ /* Find gateway addresses from the link device, which is
+ * no longer accessible inside the container. Do this
+ * before creating network interfaces, since goto
+ * out_delete_net does not work before lxc_clone. */
+ if (lxc_find_gateway_addresses(handler)) {
+ ERROR("failed to find gateway addresses");
+ lxc_sync_fini(handler);
+ return -1;
+ }
/* that should be done before the clone because we will
* fill the netdev index and use them in the child
}
}
+ if (save_phys_nics(handler->conf)) {
+ ERROR("failed to save physical nic info");
+ goto out_abort;
+ }
+
+ /*
+ * if the rootfs is not a blockdev, prevent the container from
+ * marking it readonly.
+ */
+
+ handler->pinfd = pin_rootfs(handler->conf->rootfs.path);
+ if (handler->pinfd == -1) {
+ ERROR("failed to pin the container's rootfs");
+ goto out_delete_net;
+ }
/* Create a process in a new set of namespaces */
- handler->pid = lxc_clone(do_start, handler, clone_flags);
+ handler->pid = lxc_clone(do_start, handler, handler->clone_flags);
if (handler->pid < 0) {
SYSERROR("failed to fork into a new namespace");
goto out_delete_net;
if (lxc_sync_wait_child(handler, LXC_SYNC_CONFIGURE))
failed_before_rename = 1;
- if (lxc_rename_nsgroup(name, handler->pid))
+ /* TODO - pass lxc.cgroup.dir (or user's pam cgroup) in for first argument */
+ if ((handler->cgroup = lxc_cgroup_path_create(NULL, name)) == NULL)
+ goto out_delete_net;
+
+ if (lxc_cgroup_enter(handler->cgroup, handler->pid) < 0)
goto out_delete_net;
if (failed_before_rename)
goto out_delete_net;
/* Create the network configuration */
- if (clone_flags & CLONE_NEWNET) {
+ if (handler->clone_flags & CLONE_NEWNET) {
if (lxc_assign_network(&handler->conf->network, handler->pid)) {
ERROR("failed to create the configured network");
goto out_delete_net;
}
}
- /* Tell the child to continue its initialization and wait for
- * it to exec or return an error
+ /* map the container uids - the container became an invalid
+ * userid the moment it was cloned with CLONE_NEWUSER - this
+ * call doesn't change anything immediately, but allows the
+ * container to setuid(0) (0 being mapped to something else on
+ * the host) later to become a valid uid again */
+ if (lxc_map_ids(&handler->conf->id_map, handler->pid)) {
+ ERROR("failed to set up id mapping");
+ goto out_delete_net;
+ }
+
+ /* Tell the child to continue its initialization. we'll get
+ * LXC_SYNC_CGROUP when it is ready for us to setup cgroups
*/
if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CONFIGURE))
+ goto out_delete_net;
+
+ if (setup_cgroup(handler->cgroup, &handler->conf->cgroup)) {
+ ERROR("failed to setup the cgroups for '%s'", name);
+ goto out_delete_net;
+ }
+
+
+ /* Tell the child to complete its initialization and wait for
+ * it to exec or return an error. (the child will never
+ * return LXC_SYNC_POST_CGROUP+1. It will either close the
+ * sync pipe, causing lxc_sync_barrier_child to return
+ * success, or return a different value, causing us to error
+ * out).
+ */
+ if (lxc_sync_barrier_child(handler, LXC_SYNC_POST_CGROUP))
return -1;
+ if (detect_shared_rootfs())
+ umount2(handler->conf->rootfs.mount, MNT_DETACH);
+
+ /* If child is in a fresh user namespace, chown his ptys for
+ * it */
+ if (uid_shift_ttys(handler->pid, handler->conf))
+ DEBUG("Failed to chown ptys.\n");
+
if (handler->ops->post_start(handler, handler->data))
goto out_abort;
}
lxc_sync_fini(handler);
+
+ if (handler->pinfd >= 0)
+ close(handler->pinfd);
+
return 0;
out_delete_net:
- if (clone_flags & CLONE_NEWNET)
- lxc_delete_network(&handler->conf->network);
+ if (handler->clone_flags & CLONE_NEWNET)
+ lxc_delete_network(handler);
out_abort:
lxc_abort(name, handler);
lxc_sync_fini(handler);
}
int __lxc_start(const char *name, struct lxc_conf *conf,
- struct lxc_operations* ops, void *data)
+ struct lxc_operations* ops, void *data, const char *lxcpath)
{
struct lxc_handler *handler;
int err = -1;
int status;
- handler = lxc_init(name, conf);
+ handler = lxc_init(name, conf, lxcpath);
if (!handler) {
ERROR("failed to initialize the container");
return -1;
handler->ops = ops;
handler->data = data;
+ if (must_drop_cap_sys_boot()) {
+ #if HAVE_SYS_CAPABILITY_H
+ DEBUG("Dropping cap_sys_boot\n");
+ #else
+ DEBUG("Can't drop cap_sys_boot as capabilities aren't supported\n");
+ #endif
+ } else {
+ DEBUG("Not dropping cap_sys_boot or watching utmp\n");
+ handler->conf->need_utmp_watch = 0;
+ }
+
err = lxc_spawn(handler);
if (err) {
ERROR("failed to spawn '%s'", name);
- goto out_fini;
+ goto out_fini_nonet;
}
- /* Avoid signals from terminal */
- LXC_TTY_ADD_HANDLER(SIGINT);
- LXC_TTY_ADD_HANDLER(SIGQUIT);
-
err = lxc_poll(name, handler);
if (err) {
ERROR("mainloop exited with an error");
while (waitpid(handler->pid, &status, 0) < 0 && errno == EINTR)
continue;
+ /*
+ * If the child process exited but was not signaled,
+ * it didn't call reboot. This should mean it was an
+ * lxc-execute which simply exited. In any case, treat
+ * it as a 'halt'
+ */
+ if (WIFSIGNALED(status)) {
+ switch(WTERMSIG(status)) {
+ case SIGINT: /* halt */
+ DEBUG("Container halting");
+ break;
+ case SIGHUP: /* reboot */
+ DEBUG("Container rebooting");
+ handler->conf->reboot = 1;
+ break;
+ default:
+ DEBUG("unknown exit status for init: %d\n", WTERMSIG(status));
+ break;
+ }
+ }
+
+ lxc_rename_phys_nics_on_shutdown(handler->conf);
+
err = lxc_error_set_and_log(handler->pid, status);
out_fini:
- LXC_TTY_DEL_HANDLER(SIGQUIT);
- LXC_TTY_DEL_HANDLER(SIGINT);
- lxc_unlink_nsgroup(name);
+ lxc_delete_network(handler);
+
+out_fini_nonet:
lxc_fini(name, handler);
return err;
.post_start = post_start
};
-int lxc_start(const char *name, char *const argv[], struct lxc_conf *conf)
+int lxc_start(const char *name, char *const argv[], struct lxc_conf *conf,
+ const char *lxcpath)
{
struct start_args start_arg = {
.argv = argv,
};
- if (lxc_check_inherited(-1))
+ if (lxc_check_inherited(conf, -1))
return -1;
- return __lxc_start(name, conf, &start_ops, &start_arg);
+ conf->need_utmp_watch = 1;
+ return __lxc_start(name, conf, &start_ops, &start_arg, lxcpath);
}