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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:11:47 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:11:47 +0000
commit758f820bcc0f68aeebac1717e537ca13a320b909 (patch)
tree48111ece75cf4f98316848b37a7e26356e00669e /src/chroot.c
parentInitial commit. (diff)
downloadcoreutils-upstream.tar.xz
coreutils-upstream.zip
Adding upstream version 9.1.upstream/9.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/chroot.c')
-rw-r--r--src/chroot.c432
1 files changed, 432 insertions, 0 deletions
diff --git a/src/chroot.c b/src/chroot.c
new file mode 100644
index 0000000..9839404
--- /dev/null
+++ b/src/chroot.c
@@ -0,0 +1,432 @@
+/* chroot -- run command or shell with special root directory
+ Copyright (C) 1995-2022 Free Software Foundation, Inc.
+
+ 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 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Roland McGrath. */
+
+#include <config.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <grp.h>
+
+#include "system.h"
+#include "die.h"
+#include "error.h"
+#include "ignore-value.h"
+#include "mgetgroups.h"
+#include "quote.h"
+#include "root-dev-ino.h"
+#include "userspec.h"
+#include "xstrtol.h"
+
+/* The official name of this program (e.g., no 'g' prefix). */
+#define PROGRAM_NAME "chroot"
+
+#define AUTHORS proper_name ("Roland McGrath")
+
+#ifndef MAXGID
+# define MAXGID GID_T_MAX
+#endif
+
+static inline bool uid_unset (uid_t uid) { return uid == (uid_t) -1; }
+static inline bool gid_unset (gid_t gid) { return gid == (gid_t) -1; }
+#define uid_set(x) (!uid_unset (x))
+#define gid_set(x) (!gid_unset (x))
+
+enum
+{
+ GROUPS = UCHAR_MAX + 1,
+ USERSPEC,
+ SKIP_CHDIR
+};
+
+static struct option const long_opts[] =
+{
+ {"groups", required_argument, NULL, GROUPS},
+ {"userspec", required_argument, NULL, USERSPEC},
+ {"skip-chdir", no_argument, NULL, SKIP_CHDIR},
+ {GETOPT_HELP_OPTION_DECL},
+ {GETOPT_VERSION_OPTION_DECL},
+ {NULL, 0, NULL, 0}
+};
+
+#if ! HAVE_SETGROUPS
+/* At least Interix lacks supplemental group support. */
+static int
+setgroups (size_t size, MAYBE_UNUSED gid_t const *list)
+{
+ if (size == 0)
+ {
+ /* Return success when clearing supplemental groups
+ as ! HAVE_SETGROUPS should only be the case on
+ platforms that don't support supplemental groups. */
+ return 0;
+ }
+ else
+ {
+ errno = ENOTSUP;
+ return -1;
+ }
+}
+#endif
+
+/* Determine the group IDs for the specified supplementary GROUPS,
+ which is a comma separated list of supplementary groups (names or numbers).
+ Allocate an array for the parsed IDs and store it in PGIDS,
+ which may be allocated even on parse failure.
+ Update the number of parsed groups in PN_GIDS on success.
+ Upon any failure return nonzero, and issue diagnostic if SHOW_ERRORS is true.
+ Otherwise return zero. */
+
+static int
+parse_additional_groups (char const *groups, GETGROUPS_T **pgids,
+ size_t *pn_gids, bool show_errors)
+{
+ GETGROUPS_T *gids = NULL;
+ size_t n_gids_allocated = 0;
+ size_t n_gids = 0;
+ char *buffer = xstrdup (groups);
+ char const *tmp;
+ int ret = 0;
+
+ for (tmp = strtok (buffer, ","); tmp; tmp = strtok (NULL, ","))
+ {
+ struct group *g;
+ uintmax_t value;
+
+ if (xstrtoumax (tmp, NULL, 10, &value, "") == LONGINT_OK
+ && value <= MAXGID)
+ {
+ while (isspace (to_uchar (*tmp)))
+ tmp++;
+ if (*tmp != '+')
+ {
+ /* Handle the case where the name is numeric. */
+ g = getgrnam (tmp);
+ if (g != NULL)
+ value = g->gr_gid;
+ }
+ /* Flag that we've got a group from the number. */
+ g = (struct group *) (intptr_t) ! NULL;
+ }
+ else
+ {
+ g = getgrnam (tmp);
+ if (g != NULL)
+ value = g->gr_gid;
+ }
+
+ if (g == NULL)
+ {
+ ret = -1;
+
+ if (show_errors)
+ {
+ error (0, errno, _("invalid group %s"), quote (tmp));
+ continue;
+ }
+
+ break;
+ }
+
+ if (n_gids == n_gids_allocated)
+ gids = X2NREALLOC (gids, &n_gids_allocated);
+ gids[n_gids++] = value;
+ }
+
+ if (ret == 0 && n_gids == 0)
+ {
+ if (show_errors)
+ error (0, 0, _("invalid group list %s"), quote (groups));
+ ret = -1;
+ }
+
+ *pgids = gids;
+
+ if (ret == 0)
+ *pn_gids = n_gids;
+
+ free (buffer);
+ return ret;
+}
+
+/* Return whether the passed path is equivalent to "/".
+ Note we don't compare against get_root_dev_ino() as "/"
+ could be bind mounted to a separate location. */
+
+static bool
+is_root (char const *dir)
+{
+ char *resolved = canonicalize_file_name (dir);
+ bool is_res_root = resolved && STREQ ("/", resolved);
+ free (resolved);
+ return is_res_root;
+}
+
+void
+usage (int status)
+{
+ if (status != EXIT_SUCCESS)
+ emit_try_help ();
+ else
+ {
+ printf (_("\
+Usage: %s [OPTION] NEWROOT [COMMAND [ARG]...]\n\
+ or: %s OPTION\n\
+"), program_name, program_name);
+
+ fputs (_("\
+Run COMMAND with root directory set to NEWROOT.\n\
+\n\
+"), stdout);
+
+ fputs (_("\
+ --groups=G_LIST specify supplementary groups as g1,g2,..,gN\n\
+"), stdout);
+ fputs (_("\
+ --userspec=USER:GROUP specify user and group (ID or name) to use\n\
+"), stdout);
+ printf (_("\
+ --skip-chdir do not change working directory to %s\n\
+"), quoteaf ("/"));
+
+ fputs (HELP_OPTION_DESCRIPTION, stdout);
+ fputs (VERSION_OPTION_DESCRIPTION, stdout);
+ fputs (_("\
+\n\
+If no command is given, run '\"$SHELL\" -i' (default: '/bin/sh -i').\n\
+"), stdout);
+ emit_ancillary_info (PROGRAM_NAME);
+ }
+ exit (status);
+}
+
+int
+main (int argc, char **argv)
+{
+ int c;
+
+ /* Input user and groups spec. */
+ char *userspec = NULL;
+ char const *username = NULL;
+ char const *groups = NULL;
+ bool skip_chdir = false;
+
+ /* Parsed user and group IDs. */
+ uid_t uid = -1;
+ gid_t gid = -1;
+ GETGROUPS_T *out_gids = NULL;
+ size_t n_gids = 0;
+
+ initialize_main (&argc, &argv);
+ set_program_name (argv[0]);
+ setlocale (LC_ALL, "");
+ bindtextdomain (PACKAGE, LOCALEDIR);
+ textdomain (PACKAGE);
+
+ initialize_exit_failure (EXIT_CANCELED);
+ atexit (close_stdout);
+
+ while ((c = getopt_long (argc, argv, "+", long_opts, NULL)) != -1)
+ {
+ switch (c)
+ {
+ case USERSPEC:
+ {
+ userspec = optarg;
+ /* Treat 'user:' just like 'user'
+ as we lookup the primary group by default
+ (and support doing so for UIDs as well as names. */
+ size_t userlen = strlen (userspec);
+ if (userlen && userspec[userlen - 1] == ':')
+ userspec[userlen - 1] = '\0';
+ break;
+ }
+
+ case GROUPS:
+ groups = optarg;
+ break;
+
+ case SKIP_CHDIR:
+ skip_chdir = true;
+ break;
+
+ case_GETOPT_HELP_CHAR;
+
+ case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+ default:
+ usage (EXIT_CANCELED);
+ }
+ }
+
+ if (argc <= optind)
+ {
+ error (0, 0, _("missing operand"));
+ usage (EXIT_CANCELED);
+ }
+
+ char const *newroot = argv[optind];
+ bool is_oldroot = is_root (newroot);
+
+ if (! is_oldroot && skip_chdir)
+ {
+ error (0, 0, _("option --skip-chdir only permitted if NEWROOT is old %s"),
+ quoteaf ("/"));
+ usage (EXIT_CANCELED);
+ }
+
+ if (! is_oldroot)
+ {
+ /* We have to look up users and groups twice.
+ - First, outside the chroot to load potentially necessary passwd/group
+ parsing plugins (e.g. NSS);
+ - Second, inside chroot to redo parsing in case IDs are different.
+ Within chroot lookup is the main justification for having
+ the --user option supported by the chroot command itself. */
+ if (userspec)
+ ignore_value (parse_user_spec (userspec, &uid, &gid, NULL, NULL));
+
+ /* If no gid is supplied or looked up, do so now.
+ Also lookup the username for use with getgroups. */
+ if (uid_set (uid) && (! groups || gid_unset (gid)))
+ {
+ const struct passwd *pwd;
+ if ((pwd = getpwuid (uid)))
+ {
+ if (gid_unset (gid))
+ gid = pwd->pw_gid;
+ username = pwd->pw_name;
+ }
+ }
+
+ if (groups && *groups)
+ ignore_value (parse_additional_groups (groups, &out_gids, &n_gids,
+ false));
+#if HAVE_SETGROUPS
+ else if (! groups && gid_set (gid) && username)
+ {
+ int ngroups = xgetgroups (username, gid, &out_gids);
+ if (0 < ngroups)
+ n_gids = ngroups;
+ }
+#endif
+ }
+
+ if (chroot (newroot) != 0)
+ die (EXIT_CANCELED, errno, _("cannot change root directory to %s"),
+ quoteaf (newroot));
+
+ if (! skip_chdir && chdir ("/"))
+ die (EXIT_CANCELED, errno, _("cannot chdir to root directory"));
+
+ if (argc == optind + 1)
+ {
+ /* No command. Run an interactive shell. */
+ char *shell = getenv ("SHELL");
+ if (shell == NULL)
+ shell = bad_cast ("/bin/sh");
+ argv[0] = shell;
+ argv[1] = bad_cast ("-i");
+ argv[2] = NULL;
+ }
+ else
+ {
+ /* The following arguments give the command. */
+ argv += optind + 1;
+ }
+
+ /* Attempt to set all three: supplementary groups, group ID, user ID.
+ Diagnose any failures. If any have failed, exit before execvp. */
+ if (userspec)
+ {
+ bool warn;
+ char const *err = parse_user_spec_warn (userspec, &uid, &gid,
+ NULL, NULL, &warn);
+ if (err)
+ error (warn ? 0 : EXIT_CANCELED, 0, "%s", (err));
+ }
+
+ /* If no gid is supplied or looked up, do so now.
+ Also lookup the username for use with getgroups. */
+ if (uid_set (uid) && (! groups || gid_unset (gid)))
+ {
+ const struct passwd *pwd;
+ if ((pwd = getpwuid (uid)))
+ {
+ if (gid_unset (gid))
+ gid = pwd->pw_gid;
+ username = pwd->pw_name;
+ }
+ else if (gid_unset (gid))
+ {
+ die (EXIT_CANCELED, errno,
+ _("no group specified for unknown uid: %d"), (int) uid);
+ }
+ }
+
+ GETGROUPS_T *gids = out_gids;
+ GETGROUPS_T *in_gids = NULL;
+ if (groups && *groups)
+ {
+ if (parse_additional_groups (groups, &in_gids, &n_gids, !n_gids) != 0)
+ {
+ if (! n_gids)
+ return EXIT_CANCELED;
+ /* else look-up outside the chroot worked, then go with those. */
+ }
+ else
+ gids = in_gids;
+ }
+#if HAVE_SETGROUPS
+ else if (! groups && gid_set (gid) && username)
+ {
+ int ngroups = xgetgroups (username, gid, &in_gids);
+ if (ngroups <= 0)
+ {
+ if (! n_gids)
+ die (EXIT_CANCELED, errno,
+ _("failed to get supplemental groups"));
+ /* else look-up outside the chroot worked, then go with those. */
+ }
+ else
+ {
+ n_gids = ngroups;
+ gids = in_gids;
+ }
+ }
+#endif
+
+ if ((uid_set (uid) || groups) && setgroups (n_gids, gids) != 0)
+ die (EXIT_CANCELED, errno, _("failed to set supplemental groups"));
+
+ free (in_gids);
+ free (out_gids);
+
+ if (gid_set (gid) && setgid (gid))
+ die (EXIT_CANCELED, errno, _("failed to set group-ID"));
+
+ if (uid_set (uid) && setuid (uid))
+ die (EXIT_CANCELED, errno, _("failed to set user-ID"));
+
+ /* Execute the given command. */
+ execvp (argv[0], argv);
+
+ int exit_status = errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
+ error (0, errno, _("failed to run command %s"), quote (argv[0]));
+ return exit_status;
+}