* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
-#include <sys/types.h>
-#include <sys/wait.h>
#include <dirent.h>
#include <errno.h>
#include <getopt.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
+#include <stdbool.h>
#include <unistd.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <grp.h>
+#include <sys/stat.h>
+
+#ifdef HAVE_LIBSELINUX
+# include <selinux/selinux.h>
+#endif
#include "strutils.h"
#include "nls.h"
#include "c.h"
#include "closestream.h"
#include "namespace.h"
+#include "exec_shell.h"
-static struct namespace_file{
+static struct namespace_file {
int nstype;
const char *name;
int fd;
} namespace_files[] = {
/* Careful the order is significant in this array.
*
- * The user namespace comes first, so that it is entered
- * first. This gives an unprivileged user the potential to
- * enter the other namespaces.
+ * The user namespace comes either first or last: first if
+ * you're using it to increase your privilege and last if
+ * you're using it to decrease. We enter the namespaces in
+ * two passes starting initially from offset 1 and then offset
+ * 0 if that fails.
*/
- { .nstype = CLONE_NEWUSER, .name = "ns/user", .fd = -1 },
- { .nstype = CLONE_NEWIPC, .name = "ns/ipc", .fd = -1 },
- { .nstype = CLONE_NEWUTS, .name = "ns/uts", .fd = -1 },
- { .nstype = CLONE_NEWNET, .name = "ns/net", .fd = -1 },
- { .nstype = CLONE_NEWPID, .name = "ns/pid", .fd = -1 },
- { .nstype = CLONE_NEWNS, .name = "ns/mnt", .fd = -1 },
- {}
+ { .nstype = CLONE_NEWUSER, .name = "ns/user", .fd = -1 },
+ { .nstype = CLONE_NEWCGROUP,.name = "ns/cgroup", .fd = -1 },
+ { .nstype = CLONE_NEWIPC, .name = "ns/ipc", .fd = -1 },
+ { .nstype = CLONE_NEWUTS, .name = "ns/uts", .fd = -1 },
+ { .nstype = CLONE_NEWNET, .name = "ns/net", .fd = -1 },
+ { .nstype = CLONE_NEWPID, .name = "ns/pid", .fd = -1 },
+ { .nstype = CLONE_NEWNS, .name = "ns/mnt", .fd = -1 },
+ { .nstype = 0, .name = NULL, .fd = -1 }
};
-static void usage(int status)
+static void __attribute__((__noreturn__)) usage(void)
{
- FILE *out = status == EXIT_SUCCESS ? stdout : stderr;
+ FILE *out = stdout;
fputs(USAGE_HEADER, out);
- fprintf(out, _(" %s [options] <program> [args...]\n"),
+ fprintf(out, _(" %s [options] [<program> [<argument>...]]\n"),
program_invocation_short_name);
+ fputs(USAGE_SEPARATOR, out);
+ fputs(_("Run a program with namespaces of other processes.\n"), out);
+
fputs(USAGE_OPTIONS, out);
- fputs(_(" -t, --target <pid> target process to get namespaces from\n"
- " -m, --mount [=<file>] enter mount namespace\n"
- " -u, --uts [=<file>] enter UTS namespace (hostname etc)\n"
- " -i, --ipc [=<file>] enter System V IPC namespace\n"
- " -n, --net [=<file>] enter network namespace\n"
- " -p, --pid [=<file>] enter pid namespace\n"
- " -U, --user [=<file>] enter user namespace\n"
- " -e, --exec don't fork before exec'ing <program>\n"
- " -r, --root [=<dir>] set the root directory\n"
- " -w, --wd [=<dir>] set the working directory\n"), out);
+ fputs(_(" -a, --all enter all namespaces\n"), out);
+ fputs(_(" -t, --target <pid> target process to get namespaces from\n"), out);
+ fputs(_(" -m, --mount[=<file>] enter mount namespace\n"), out);
+ fputs(_(" -u, --uts[=<file>] enter UTS namespace (hostname etc)\n"), out);
+ fputs(_(" -i, --ipc[=<file>] enter System V IPC namespace\n"), out);
+ fputs(_(" -n, --net[=<file>] enter network namespace\n"), out);
+ fputs(_(" -p, --pid[=<file>] enter pid namespace\n"), out);
+ fputs(_(" -C, --cgroup[=<file>] enter cgroup namespace\n"), out);
+ fputs(_(" -U, --user[=<file>] enter user namespace\n"), out);
+ fputs(_(" -S, --setuid <uid> set uid in entered namespace\n"), out);
+ fputs(_(" -G, --setgid <gid> set gid in entered namespace\n"), out);
+ fputs(_(" --preserve-credentials do not touch uids or gids\n"), out);
+ fputs(_(" -r, --root[=<dir>] set the root directory\n"), out);
+ fputs(_(" -w, --wd[=<dir>] set the working directory\n"), out);
+ fputs(_(" -F, --no-fork do not fork before exec'ing <program>\n"), out);
+#ifdef HAVE_LIBSELINUX
+ fputs(_(" -Z, --follow-context set SELinux context according to --target PID\n"), out);
+#endif
+
fputs(USAGE_SEPARATOR, out);
- fputs(USAGE_HELP, out);
- fputs(USAGE_VERSION, out);
- fprintf(out, USAGE_MAN_TAIL("nsenter(1)"));
+ printf(USAGE_HELP_OPTIONS(24));
+ printf(USAGE_MAN_TAIL("nsenter(1)"));
- exit(status);
+ exit(EXIT_SUCCESS);
}
static pid_t namespace_target_pid = 0;
if (!path && namespace_target_pid) {
snprintf(pathbuf, sizeof(pathbuf), "/proc/%u/%s",
- namespace_target_pid, type);
+ namespace_target_pid, type);
path = pathbuf;
}
if (!path)
- err(EXIT_FAILURE, _("No filename and no target pid supplied for %s"),
- type);
+ errx(EXIT_FAILURE,
+ _("neither filename nor target pid supplied for %s"),
+ type);
if (*fd >= 0)
close(*fd);
*fd = open(path, O_RDONLY);
if (*fd < 0)
- err(EXIT_FAILURE, _("open of '%s' failed"), path);
+ err(EXIT_FAILURE, _("cannot open %s"), path);
}
static void open_namespace_fd(int nstype, const char *path)
return;
}
/* This should never happen */
- err(EXIT_FAILURE, "Unrecognized namespace type");
+ assert(nsfile->nstype);
+}
+
+static int get_ns_ino(const char *path, ino_t *ino)
+{
+ struct stat st;
+
+ if (stat(path, &st) != 0)
+ return -errno;
+ *ino = st.st_ino;
+ return 0;
+}
+
+static int is_same_namespace(pid_t a, pid_t b, const char *type)
+{
+ char path[PATH_MAX];
+ ino_t a_ino = 0, b_ino = 0;
+
+ snprintf(path, sizeof(path), "/proc/%u/%s", a, type);
+ if (get_ns_ino(path, &a_ino) != 0)
+ err(EXIT_FAILURE, _("stat of %s failed"), path);
+
+ snprintf(path, sizeof(path), "/proc/%u/%s", b, type);
+ if (get_ns_ino(path, &b_ino) != 0)
+ err(EXIT_FAILURE, _("stat of %s failed"), path);
+
+ return a_ino == b_ino;
}
static void continue_as_child(void)
/* Return the child's exit code if possible */
if (WIFEXITED(status)) {
exit(WEXITSTATUS(status));
- }
- else if (WIFSIGNALED(status)) {
+ } else if (WIFSIGNALED(status)) {
kill(getpid(), WTERMSIG(status));
}
exit(EXIT_FAILURE);
int main(int argc, char *argv[])
{
+ enum {
+ OPT_PRESERVE_CRED = CHAR_MAX + 1
+ };
static const struct option longopts[] = {
+ { "all", no_argument, NULL, 'a' },
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V'},
{ "target", required_argument, NULL, 't' },
{ "net", optional_argument, NULL, 'n' },
{ "pid", optional_argument, NULL, 'p' },
{ "user", optional_argument, NULL, 'U' },
- { "exec", no_argument, NULL, 'e' },
+ { "cgroup", optional_argument, NULL, 'C' },
+ { "setuid", required_argument, NULL, 'S' },
+ { "setgid", required_argument, NULL, 'G' },
{ "root", optional_argument, NULL, 'r' },
{ "wd", optional_argument, NULL, 'w' },
+ { "no-fork", no_argument, NULL, 'F' },
+ { "preserve-credentials", no_argument, NULL, OPT_PRESERVE_CRED },
+#ifdef HAVE_LIBSELINUX
+ { "follow-context", no_argument, NULL, 'Z' },
+#endif
{ NULL, 0, NULL, 0 }
};
struct namespace_file *nsfile;
- int do_fork = 0;
- int c;
-
- setlocale(LC_MESSAGES, "");
+ int c, pass, namespaces = 0, setgroups_nerrs = 0, preserve_cred = 0;
+ bool do_rd = false, do_wd = false, force_uid = false, force_gid = false;
+ bool do_all = false;
+ int do_fork = -1; /* unknown yet */
+ uid_t uid = 0;
+ gid_t gid = 0;
+#ifdef HAVE_LIBSELINUX
+ bool selinux = 0;
+#endif
+
+ setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
- while((c = getopt_long(argc, argv, "hVt:m::u::i::n::p::U::er::w::", longopts, NULL)) != -1) {
- switch(c) {
+ while ((c =
+ getopt_long(argc, argv, "+ahVt:m::u::i::n::p::C::U::S:G:r::w::FZ",
+ longopts, NULL)) != -1) {
+ switch (c) {
case 'h':
- usage(EXIT_SUCCESS);
+ usage();
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
+ case 'a':
+ do_all = true;
+ break;
case 't':
- namespace_target_pid = strtoul_or_err(optarg, _("failed to parse pid"));
+ namespace_target_pid =
+ strtoul_or_err(optarg, _("failed to parse pid"));
break;
case 'm':
- open_namespace_fd(CLONE_NEWNS, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWNS, optarg);
+ else
+ namespaces |= CLONE_NEWNS;
break;
case 'u':
- open_namespace_fd(CLONE_NEWUTS, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWUTS, optarg);
+ else
+ namespaces |= CLONE_NEWUTS;
break;
case 'i':
- open_namespace_fd(CLONE_NEWIPC, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWIPC, optarg);
+ else
+ namespaces |= CLONE_NEWIPC;
break;
case 'n':
- open_namespace_fd(CLONE_NEWNET, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWNET, optarg);
+ else
+ namespaces |= CLONE_NEWNET;
break;
case 'p':
- do_fork = 1;
- open_namespace_fd(CLONE_NEWPID, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWPID, optarg);
+ else
+ namespaces |= CLONE_NEWPID;
+ break;
+ case 'C':
+ if (optarg)
+ open_namespace_fd(CLONE_NEWCGROUP, optarg);
+ else
+ namespaces |= CLONE_NEWCGROUP;
break;
case 'U':
- open_namespace_fd(CLONE_NEWUSER, optarg);
+ if (optarg)
+ open_namespace_fd(CLONE_NEWUSER, optarg);
+ else
+ namespaces |= CLONE_NEWUSER;
+ break;
+ case 'S':
+ uid = strtoul_or_err(optarg, _("failed to parse uid"));
+ force_uid = true;
+ break;
+ case 'G':
+ gid = strtoul_or_err(optarg, _("failed to parse gid"));
+ force_gid = true;
break;
- case 'e':
+ case 'F':
do_fork = 0;
break;
case 'r':
- open_target_fd(&root_fd, "root", optarg);
+ if (optarg)
+ open_target_fd(&root_fd, "root", optarg);
+ else
+ do_rd = true;
break;
case 'w':
- open_target_fd(&wd_fd, "cwd", optarg);
+ if (optarg)
+ open_target_fd(&wd_fd, "cwd", optarg);
+ else
+ do_wd = true;
break;
+ case OPT_PRESERVE_CRED:
+ preserve_cred = 1;
+ break;
+#ifdef HAVE_LIBSELINUX
+ case 'Z':
+ selinux = 1;
+ break;
+#endif
default:
- usage(EXIT_FAILURE);
+ errtryhelp(EXIT_FAILURE);
}
}
- if(optind >= argc)
- usage(EXIT_FAILURE);
+#ifdef HAVE_LIBSELINUX
+ if (selinux && is_selinux_enabled() > 0) {
+ char *scon = NULL;
+
+ if (!namespace_target_pid)
+ errx(EXIT_FAILURE, _("no target PID specified for --follow-context"));
+ if (getpidcon(namespace_target_pid, &scon) < 0)
+ errx(EXIT_FAILURE, _("failed to get %d SELinux context"),
+ (int) namespace_target_pid);
+ if (setexeccon(scon) < 0)
+ errx(EXIT_FAILURE, _("failed to set exec context to '%s'"), scon);
+ freecon(scon);
+ }
+#endif
+
+ if (do_all) {
+ if (!namespace_target_pid)
+ errx(EXIT_FAILURE, _("no target PID specified for --all"));
+ for (nsfile = namespace_files; nsfile->nstype; nsfile++) {
+ if (nsfile->fd >= 0)
+ continue; /* namespace already specified */
+
+ /* It is not permitted to use setns(2) to reenter the caller's
+ * current user namespace; see setns(2) man page for more details.
+ */
+ if (nsfile->nstype & CLONE_NEWUSER
+ && is_same_namespace(getpid(), namespace_target_pid, nsfile->name))
+ continue;
+
+ namespaces |= nsfile->nstype;
+ }
+ }
+
+ /*
+ * Open remaining namespace and directory descriptors.
+ */
+ for (nsfile = namespace_files; nsfile->nstype; nsfile++)
+ if (nsfile->nstype & namespaces)
+ open_namespace_fd(nsfile->nstype, NULL);
+ if (do_rd)
+ open_target_fd(&root_fd, "root", NULL);
+ if (do_wd)
+ open_target_fd(&wd_fd, "cwd", NULL);
/*
- * Now that we know which namespaces we want to enter, enter them.
+ * Update namespaces variable to contain all requested namespaces
*/
for (nsfile = namespace_files; nsfile->nstype; nsfile++) {
if (nsfile->fd < 0)
continue;
- if (setns(nsfile->fd, nsfile->nstype))
- err(EXIT_FAILURE, _("setns of '%s' failed"),
- nsfile->name);
- close(nsfile->fd);
- nsfile->fd = -1;
+ namespaces |= nsfile->nstype;
+ }
+
+ /* for user namespaces we always set UID and GID (default is 0)
+ * and clear root's groups if --preserve-credentials is no specified */
+ if ((namespaces & CLONE_NEWUSER) && !preserve_cred) {
+ force_uid = true, force_gid = true;
+
+ /* We call setgroups() before and after we enter user namespace,
+ * let's complain only if both fail */
+ if (setgroups(0, NULL) != 0)
+ setgroups_nerrs++;
+ }
+
+ /*
+ * Now that we know which namespaces we want to enter, enter
+ * them. Do this in two passes, not entering the user
+ * namespace on the first pass. So if we're deprivileging the
+ * container we'll enter the user namespace last and if we're
+ * privileging it then we enter the user namespace first
+ * (because the initial setns will fail).
+ */
+ for (pass = 0; pass < 2; pass ++) {
+ for (nsfile = namespace_files + 1 - pass; nsfile->nstype; nsfile++) {
+ if (nsfile->fd < 0)
+ continue;
+ if (nsfile->nstype == CLONE_NEWPID && do_fork == -1)
+ do_fork = 1;
+ if (setns(nsfile->fd, nsfile->nstype)) {
+ if (pass != 0)
+ err(EXIT_FAILURE,
+ _("reassociate to namespace '%s' failed"),
+ nsfile->name);
+ else
+ continue;
+ }
+
+ close(nsfile->fd);
+ nsfile->fd = -1;
+ }
}
/* Remember the current working directory if I'm not changing it */
if (root_fd >= 0 && wd_fd < 0) {
wd_fd = open(".", O_RDONLY);
if (wd_fd < 0)
- err(EXIT_FAILURE, _("open of . failed"));
+ err(EXIT_FAILURE,
+ _("cannot open current working directory"));
}
/* Change the root directory */
if (root_fd >= 0) {
if (fchdir(root_fd) < 0)
- err(EXIT_FAILURE, _("fchdir to root_fd failed"));
+ err(EXIT_FAILURE,
+ _("change directory by root file descriptor failed"));
if (chroot(".") < 0)
err(EXIT_FAILURE, _("chroot failed"));
/* Change the working directory */
if (wd_fd >= 0) {
if (fchdir(wd_fd) < 0)
- err(EXIT_FAILURE, _("fchdir to wd_fd failed"));
+ err(EXIT_FAILURE,
+ _("change directory by working directory file descriptor failed"));
close(wd_fd);
wd_fd = -1;
}
- if (do_fork)
+ if (do_fork == 1)
continue_as_child();
- execvp(argv[optind], argv + optind);
+ if (force_uid || force_gid) {
+ if (force_gid && setgroups(0, NULL) != 0 && setgroups_nerrs) /* drop supplementary groups */
+ err(EXIT_FAILURE, _("setgroups failed"));
+ if (force_gid && setgid(gid) < 0) /* change GID */
+ err(EXIT_FAILURE, _("setgid failed"));
+ if (force_uid && setuid(uid) < 0) /* change UID */
+ err(EXIT_FAILURE, _("setuid failed"));
+ }
- err(EXIT_FAILURE, _("exec %s failed"), argv[optind]);
+ if (optind < argc) {
+ execvp(argv[optind], argv + optind);
+ errexec(argv[optind]);
+ }
+ exec_shell();
}
projects / thirdparty / util-linux.git / blobdiff