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Diffstat (limited to 'src/chcon.c')
| -rw-r--r-- | src/chcon.c | 588 |
1 files changed, 588 insertions, 0 deletions
diff --git a/src/chcon.c b/src/chcon.c new file mode 100644 index 0000000..41419b8 --- /dev/null +++ b/src/chcon.c @@ -0,0 +1,588 @@ +/* chcon -- change security context of files + Copyright (C) 2005-2023 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/>. */ + +#include <config.h> +#include <stdio.h> +#include <sys/types.h> +#include <getopt.h> +#include <selinux/selinux.h> + +#include "system.h" +#include "dev-ino.h" +#include "ignore-value.h" +#include "quote.h" +#include "root-dev-ino.h" +#include "selinux-at.h" +#include "xfts.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "chcon" + +#define AUTHORS \ + proper_name ("Russell Coker"), \ + proper_name ("Jim Meyering") + +/* If nonzero, and the systems has support for it, change the context + of symbolic links rather than any files they point to. */ +static bool affect_symlink_referent; + +/* If true, change the modes of directories recursively. */ +static bool recurse; + +/* Level of verbosity. */ +static bool verbose; + +/* Pointer to the device and inode numbers of '/', when --recursive. + Otherwise nullptr. */ +static struct dev_ino *root_dev_ino; + +/* The name of the context file is being given. */ +static char const *specified_context; + +/* Specific components of the context */ +static char const *specified_user; +static char const *specified_role; +static char const *specified_range; +static char const *specified_type; + +/* For long options that have no equivalent short option, use a + non-character as a pseudo short option, starting with CHAR_MAX + 1. */ +enum +{ + DEREFERENCE_OPTION = CHAR_MAX + 1, + NO_PRESERVE_ROOT, + PRESERVE_ROOT, + REFERENCE_FILE_OPTION +}; + +static struct option const long_options[] = +{ + {"recursive", no_argument, nullptr, 'R'}, + {"dereference", no_argument, nullptr, DEREFERENCE_OPTION}, + {"no-dereference", no_argument, nullptr, 'h'}, + {"no-preserve-root", no_argument, nullptr, NO_PRESERVE_ROOT}, + {"preserve-root", no_argument, nullptr, PRESERVE_ROOT}, + {"reference", required_argument, nullptr, REFERENCE_FILE_OPTION}, + {"user", required_argument, nullptr, 'u'}, + {"role", required_argument, nullptr, 'r'}, + {"type", required_argument, nullptr, 't'}, + {"range", required_argument, nullptr, 'l'}, + {"verbose", no_argument, nullptr, 'v'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {nullptr, 0, nullptr, 0} +}; + +/* Given a security context, CONTEXT, derive a context_t (*RET), + setting any portions selected via the global variables, specified_user, + specified_role, etc. */ +static int +compute_context_from_mask (char const *context, context_t *ret) +{ + bool ok = true; + context_t new_context = context_new (context); + if (!new_context) + { + error (0, errno, _("failed to create security context: %s"), + quote (context)); + return 1; + } + +#define SET_COMPONENT(C, comp) \ + do \ + { \ + if (specified_ ## comp \ + && context_ ## comp ## _set ((C), specified_ ## comp)) \ + { \ + error (0, errno, \ + _("failed to set %s security context component to %s"), \ + #comp, quote (specified_ ## comp)); \ + ok = false; \ + } \ + } \ + while (0) + + SET_COMPONENT (new_context, user); + SET_COMPONENT (new_context, range); + SET_COMPONENT (new_context, role); + SET_COMPONENT (new_context, type); + + if (!ok) + { + int saved_errno = errno; + context_free (new_context); + errno = saved_errno; + return 1; + } + + *ret = new_context; + return 0; +} + +/* Change the context of FILE, using specified components. + If it is a directory and -R is given, recurse. + Return 0 if successful, 1 if errors occurred. */ + +static int +change_file_context (int fd, char const *file) +{ + char *file_context = nullptr; + context_t context IF_LINT (= 0); + char const * context_string; + int errors = 0; + + if (specified_context == nullptr) + { + int status = (affect_symlink_referent + ? getfileconat (fd, file, &file_context) + : lgetfileconat (fd, file, &file_context)); + + if (status < 0 && errno != ENODATA) + { + error (0, errno, _("failed to get security context of %s"), + quoteaf (file)); + return 1; + } + + /* If the file doesn't have a context, and we're not setting all of + the context components, there isn't really an obvious default. + Thus, we just give up. */ + if (file_context == nullptr) + { + error (0, 0, _("can't apply partial context to unlabeled file %s"), + quoteaf (file)); + return 1; + } + + if (compute_context_from_mask (file_context, &context)) + return 1; + + context_string = context_str (context); + } + else + { + context_string = specified_context; + } + + if (file_context == nullptr || ! STREQ (context_string, file_context)) + { + int fail = (affect_symlink_referent + ? setfileconat (fd, file, context_string) + : lsetfileconat (fd, file, context_string)); + + if (fail) + { + errors = 1; + error (0, errno, _("failed to change context of %s to %s"), + quoteaf_n (0, file), quote_n (1, context_string)); + } + } + + if (specified_context == nullptr) + { + context_free (context); + freecon (file_context); + } + + return errors; +} + +/* Change the context of FILE. + Return true if successful. This function is called + once for every file system object that fts encounters. */ + +static bool +process_file (FTS *fts, FTSENT *ent) +{ + char const *file_full_name = ent->fts_path; + char const *file = ent->fts_accpath; + const struct stat *file_stats = ent->fts_statp; + bool ok = true; + + switch (ent->fts_info) + { + case FTS_D: + if (recurse) + { + if (ROOT_DEV_INO_CHECK (root_dev_ino, ent->fts_statp)) + { + /* This happens e.g., with "chcon -R --preserve-root ... /" + and with "chcon -RH --preserve-root ... symlink-to-root". */ + ROOT_DEV_INO_WARN (file_full_name); + /* Tell fts not to traverse into this hierarchy. */ + fts_set (fts, ent, FTS_SKIP); + /* Ensure that we do not process "/" on the second visit. */ + ignore_value (fts_read (fts)); + return false; + } + return true; + } + break; + + case FTS_DP: + if (! recurse) + return true; + break; + + case FTS_NS: + /* For a top-level file or directory, this FTS_NS (stat failed) + indicator is determined at the time of the initial fts_open call. + With programs like chmod, chown, and chgrp, that modify + permissions, it is possible that the file in question is + accessible when control reaches this point. So, if this is + the first time we've seen the FTS_NS for this file, tell + fts_read to stat it "again". */ + if (ent->fts_level == 0 && ent->fts_number == 0) + { + ent->fts_number = 1; + fts_set (fts, ent, FTS_AGAIN); + return true; + } + error (0, ent->fts_errno, _("cannot access %s"), + quoteaf (file_full_name)); + ok = false; + break; + + case FTS_ERR: + error (0, ent->fts_errno, "%s", quotef (file_full_name)); + ok = false; + break; + + case FTS_DNR: + error (0, ent->fts_errno, _("cannot read directory %s"), + quoteaf (file_full_name)); + ok = false; + break; + + case FTS_DC: /* directory that causes cycles */ + if (cycle_warning_required (fts, ent)) + { + emit_cycle_warning (file_full_name); + return false; + } + break; + + default: + break; + } + + if (ent->fts_info == FTS_DP + && ok && ROOT_DEV_INO_CHECK (root_dev_ino, file_stats)) + { + ROOT_DEV_INO_WARN (file_full_name); + ok = false; + } + + if (ok) + { + if (verbose) + printf (_("changing security context of %s\n"), + quoteaf (file_full_name)); + + if (change_file_context (fts->fts_cwd_fd, file) != 0) + ok = false; + } + + if ( ! recurse) + fts_set (fts, ent, FTS_SKIP); + + return ok; +} + +/* Recursively operate on the specified FILES (the last entry + of which is null). BIT_FLAGS controls how fts works. + Return true if successful. */ + +static bool +process_files (char **files, int bit_flags) +{ + bool ok = true; + + FTS *fts = xfts_open (files, bit_flags, nullptr); + + while (true) + { + FTSENT *ent; + + ent = fts_read (fts); + if (ent == nullptr) + { + if (errno != 0) + { + /* FIXME: try to give a better message */ + error (0, errno, _("fts_read failed")); + ok = false; + } + break; + } + + ok &= process_file (fts, ent); + } + + if (fts_close (fts) != 0) + { + error (0, errno, _("fts_close failed")); + ok = false; + } + + return ok; +} + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("\ +Usage: %s [OPTION]... CONTEXT FILE...\n\ + or: %s [OPTION]... [-u USER] [-r ROLE] [-l RANGE] [-t TYPE] FILE...\n\ + or: %s [OPTION]... --reference=RFILE FILE...\n\ +"), + program_name, program_name, program_name); + fputs (_("\ +Change the SELinux security context of each FILE to CONTEXT.\n\ +With --reference, change the security context of each FILE to that of RFILE.\n\ +"), stdout); + + emit_mandatory_arg_note (); + + fputs (_("\ + --dereference affect the referent of each symbolic link (this is\n\ + the default), rather than the symbolic link itself\n\ + -h, --no-dereference affect symbolic links instead of any referenced file\n\ +"), stdout); + fputs (_("\ + -u, --user=USER set user USER in the target security context\n\ + -r, --role=ROLE set role ROLE in the target security context\n\ + -t, --type=TYPE set type TYPE in the target security context\n\ + -l, --range=RANGE set range RANGE in the target security context\n\ +"), stdout); + fputs (_("\ + --no-preserve-root do not treat '/' specially (the default)\n\ + --preserve-root fail to operate recursively on '/'\n\ +"), stdout); + fputs (_("\ + --reference=RFILE use RFILE's security context rather than specifying\n\ + a CONTEXT value\n\ +"), stdout); + fputs (_("\ + -R, --recursive operate on files and directories recursively\n\ +"), stdout); + fputs (_("\ + -v, --verbose output a diagnostic for every file processed\n\ +"), stdout); + fputs (_("\ +\n\ +The following options modify how a hierarchy is traversed when the -R\n\ +option is also specified. If more than one is specified, only the final\n\ +one takes effect.\n\ +\n\ + -H if a command line argument is a symbolic link\n\ + to a directory, traverse it\n\ + -L traverse every symbolic link to a directory\n\ + encountered\n\ + -P do not traverse any symbolic links (default)\n\ +\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + /* Bit flags that control how fts works. */ + int bit_flags = FTS_PHYSICAL; + + /* 1 if --dereference, 0 if --no-dereference, -1 if neither has been + specified. */ + int dereference = -1; + + bool ok; + bool preserve_root = false; + bool component_specified = false; + char *reference_file = nullptr; + int optc; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + while ((optc = getopt_long (argc, argv, "HLPRhvu:r:t:l:", + long_options, nullptr)) + != -1) + { + switch (optc) + { + case 'H': /* Traverse command-line symlinks-to-directories. */ + bit_flags = FTS_COMFOLLOW | FTS_PHYSICAL; + break; + + case 'L': /* Traverse all symlinks-to-directories. */ + bit_flags = FTS_LOGICAL; + break; + + case 'P': /* Traverse no symlinks-to-directories. */ + bit_flags = FTS_PHYSICAL; + break; + + case 'h': /* --no-dereference: affect symlinks */ + dereference = 0; + break; + + case DEREFERENCE_OPTION: /* --dereference: affect the referent + of each symlink */ + dereference = 1; + break; + + case NO_PRESERVE_ROOT: + preserve_root = false; + break; + + case PRESERVE_ROOT: + preserve_root = true; + break; + + case REFERENCE_FILE_OPTION: + reference_file = optarg; + break; + + case 'R': + recurse = true; + break; + + case 'f': + /* ignore */ + break; + + case 'v': + verbose = true; + break; + + case 'u': + specified_user = optarg; + component_specified = true; + break; + + case 'r': + specified_role = optarg; + component_specified = true; + break; + + case 't': + specified_type = optarg; + component_specified = true; + break; + + case 'l': + specified_range = optarg; + component_specified = true; + break; + + case_GETOPT_HELP_CHAR; + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + default: + usage (EXIT_FAILURE); + } + } + + if (recurse) + { + if (bit_flags == FTS_PHYSICAL) + { + if (dereference == 1) + error (EXIT_FAILURE, 0, + _("-R --dereference requires either -H or -L")); + affect_symlink_referent = false; + } + else + { + if (dereference == 0) + error (EXIT_FAILURE, 0, _("-R -h requires -P")); + affect_symlink_referent = true; + } + } + else + { + bit_flags = FTS_PHYSICAL; + affect_symlink_referent = (dereference != 0); + } + + if (argc - optind < (reference_file || component_specified ? 1 : 2)) + { + if (argc <= optind) + error (0, 0, _("missing operand")); + else + error (0, 0, _("missing operand after %s"), quote (argv[argc - 1])); + usage (EXIT_FAILURE); + } + + if (reference_file) + { + char *ref_context = nullptr; + + if (getfilecon (reference_file, &ref_context) < 0) + error (EXIT_FAILURE, errno, _("failed to get security context of %s"), + quoteaf (reference_file)); + + specified_context = ref_context; + } + else if (component_specified) + { + /* FIXME: it's already null, so this is a no-op. */ + specified_context = nullptr; + } + else + { + specified_context = argv[optind++]; + if (0 < is_selinux_enabled () + && security_check_context (specified_context) < 0) + error (EXIT_FAILURE, errno, _("invalid context: %s"), + quote (specified_context)); + } + + if (reference_file && component_specified) + { + error (0, 0, _("conflicting security context specifiers given")); + usage (EXIT_FAILURE); + } + + if (recurse && preserve_root) + { + static struct dev_ino dev_ino_buf; + root_dev_ino = get_root_dev_ino (&dev_ino_buf); + if (root_dev_ino == nullptr) + error (EXIT_FAILURE, errno, _("failed to get attributes of %s"), + quoteaf ("/")); + } + else + { + root_dev_ino = nullptr; + } + + ok = process_files (argv + optind, bit_flags | FTS_NOSTAT); + + return ok ? EXIT_SUCCESS : EXIT_FAILURE; +} |