/*
  setfiles: based on policycoreutils 2.0.19
  policycoreutils was released under GPL 2.
  Port to BusyBox (c) 2007 by Yuichi Nakamura <ynakam@hitachisoft.jp>
*/
//config:config SETFILES
//config:       bool "setfiles"
//config:       default n
//config:       depends on SELINUX
//config:       help
//config:         Enable support to modify to relabel files.
//config:         Notice: If you built libselinux with -D_FILE_OFFSET_BITS=64,
//config:         (It is default in libselinux's Makefile), you _must_ enable
//config:         CONFIG_LFS.
//config:
//config:config FEATURE_SETFILES_CHECK_OPTION
//config:       bool "Enable check option"
//config:       default n
//config:       depends on SETFILES
//config:       help
//config:         Support "-c" option (check the validity of the contexts against
//config:         the specified binary policy) for setfiles. Requires libsepol.
//config:
//config:config RESTORECON
//config:       bool "restorecon"
//config:       default n
//config:       depends on SELINUX
//config:       help
//config:         Enable support to relabel files. The feature is almost
//config:         the same as setfiles, but usage is a little different.

//applet:IF_SETFILES(APPLET(setfiles, BB_DIR_SBIN, BB_SUID_DROP))
//applet:IF_RESTORECON(APPLET_ODDNAME(restorecon, setfiles, BB_DIR_SBIN, BB_SUID_DROP, restorecon))

//kbuild:lib-$(CONFIG_SETFILES) += setfiles.o
//kbuild:lib-$(CONFIG_RESTORECON) += setfiles.o

//usage:#define setfiles_trivial_usage
//usage:       "[-dnpqsvW] [-e DIR]... [-o FILE] [-r alt_root_path]"
//usage:        IF_FEATURE_SETFILES_CHECK_OPTION(
//usage:       " [-c policyfile] spec_file"
//usage:        )
//usage:       " pathname"
//usage:#define setfiles_full_usage "\n\n"
//usage:       "Reset file contexts under pathname according to spec_file\n"
//usage:        IF_FEATURE_SETFILES_CHECK_OPTION(
//usage:     "\n        -c FILE Check the validity of the contexts against the specified binary policy"
//usage:        )
//usage:     "\n        -d      Show which specification matched each file"
//usage:     "\n        -l      Log changes in file labels to syslog"
//TODO: log to syslog is not yet implemented, it goes to stdout only now
//usage:     "\n        -n      Don't change any file labels"
//usage:     "\n        -q      Suppress warnings"
//usage:     "\n        -r DIR  Use an alternate root path"
//usage:     "\n        -e DIR  Exclude DIR"
//usage:     "\n        -F      Force reset of context to match file_context for customizable files"
//usage:     "\n        -o FILE Save list of files with incorrect context"
//usage:     "\n        -s      Take a list of files from stdin (instead of command line)"
//usage:     "\n        -v      Show changes in file labels, if type or role are changing"
//usage:     "\n        -vv     Show changes in file labels, if type, role, or user are changing"
//usage:     "\n        -W      Display warnings about entries that had no matching files"
//usage:
//usage:#define restorecon_trivial_usage
//usage:       "[-iFnRv] [-e EXCLUDEDIR]... [-o FILE] [-f FILE]"
//usage:#define restorecon_full_usage "\n\n"
//usage:       "Reset security contexts of files in pathname\n"
//usage:     "\n        -i      Ignore files that don't exist"
//usage:     "\n        -f FILE File with list of files to process"
//usage:     "\n        -e DIR  Directory to exclude"
//usage:     "\n        -R,-r   Recurse"
//usage:     "\n        -n      Don't change any file labels"
//usage:     "\n        -o FILE Save list of files with incorrect context"
//usage:     "\n        -v      Verbose"
//usage:     "\n        -vv     Show changed labels"
//usage:     "\n        -F      Force reset of context to match file_context"
//usage:     "\n                for customizable files, or the user section,"
//usage:     "\n                if it has changed"

#include "libbb.h"
#include "common_bufsiz.h"
#if ENABLE_FEATURE_SETFILES_CHECK_OPTION
#include <sepol/sepol.h>
#endif

#define MAX_EXCLUDES 50

struct edir {
        char *directory;
        size_t size;
};

struct globals {
        FILE *outfile;
        char *policyfile;
        char *rootpath;
        int rootpathlen;
        unsigned count;
        int excludeCtr;
        int errors;
        int verbose; /* getopt32 uses it, has to be int */
        smallint recurse; /* Recursive descent */
        smallint follow_mounts;
        /* Behavior flags determined based on setfiles vs. restorecon */
        smallint expand_realpath;  /* Expand paths via realpath */
        smallint abort_on_error; /* Abort the file tree walk upon an error */
        int add_assoc; /* Track inode associations for conflict detection */
        int matchpathcon_flags; /* Flags to matchpathcon */
        dev_t dev_id; /* Device id where target file exists */
        int nerr;
        struct edir excludeArray[MAX_EXCLUDES];
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
void BUG_setfiles_globals_too_big(void);
#define INIT_G() do { \
        setup_common_bufsiz(); \
        if (sizeof(G) > COMMON_BUFSIZE) \
                BUG_setfiles_globals_too_big(); \
        /* memset(&G, 0, sizeof(G)); - already is */ \
} while (0)
#define outfile            (G.outfile           )
#define policyfile         (G.policyfile        )
#define rootpath           (G.rootpath          )
#define rootpathlen        (G.rootpathlen       )
#define count              (G.count             )
#define excludeCtr         (G.excludeCtr        )
#define errors             (G.errors            )
#define verbose            (G.verbose           )
#define recurse            (G.recurse           )
#define follow_mounts      (G.follow_mounts     )
#define expand_realpath    (G.expand_realpath   )
#define abort_on_error     (G.abort_on_error    )
#define add_assoc          (G.add_assoc         )
#define matchpathcon_flags (G.matchpathcon_flags)
#define dev_id             (G.dev_id            )
#define nerr               (G.nerr              )
#define excludeArray       (G.excludeArray      )

/* Must match getopt32 string! */
enum {
        OPT_d = (1 << 0),
        OPT_e = (1 << 1),
        OPT_f = (1 << 2),
        OPT_i = (1 << 3),
        OPT_l = (1 << 4),
        OPT_n = (1 << 5),
        OPT_p = (1 << 6),
        OPT_q = (1 << 7),
        OPT_r = (1 << 8),
        OPT_s = (1 << 9),
        OPT_v = (1 << 10),
        OPT_o = (1 << 11),
        OPT_F = (1 << 12),
        OPT_W = (1 << 13),
        OPT_c = (1 << 14), /* c only for setfiles */
        OPT_R = (1 << 14), /* R only for restorecon */
};
#define FLAG_d_debug         (option_mask32 & OPT_d)
#define FLAG_e               (option_mask32 & OPT_e)
#define FLAG_f               (option_mask32 & OPT_f)
#define FLAG_i_ignore_enoent (option_mask32 & OPT_i)
#define FLAG_l_take_log      (option_mask32 & OPT_l)
#define FLAG_n_dry_run       (option_mask32 & OPT_n)
#define FLAG_p_progress      (option_mask32 & OPT_p)
#define FLAG_q_quiet         (option_mask32 & OPT_q)
#define FLAG_r               (option_mask32 & OPT_r)
#define FLAG_s               (option_mask32 & OPT_s)
#define FLAG_v               (option_mask32 & OPT_v)
#define FLAG_o               (option_mask32 & OPT_o)
#define FLAG_F_force         (option_mask32 & OPT_F)
#define FLAG_W_warn_no_match (option_mask32 & OPT_W)
#define FLAG_c               (option_mask32 & OPT_c)
#define FLAG_R               (option_mask32 & OPT_R)


static void qprintf(const char *fmt UNUSED_PARAM, ...)
{
        /* quiet, do nothing */
}

static void inc_err(void)
{
        nerr++;
        if (nerr > 9 && !FLAG_d_debug) {
                bb_error_msg_and_die("exiting after 10 errors");
        }
}

static void add_exclude(const char *directory)
{
        struct stat sb;
        size_t len;

        if (directory == NULL || directory[0] != '/') {
                bb_error_msg_and_die("full path required for exclude: %s", directory);
        }
        if (lstat(directory, &sb)) {
                bb_error_msg("directory \"%s\" not found, ignoring", directory);
                return;
        }
        if ((sb.st_mode & S_IFDIR) == 0) {
                bb_error_msg("\"%s\" is not a directory: mode %o, ignoring",
                        directory, sb.st_mode);
                return;
        }
        if (excludeCtr == MAX_EXCLUDES) {
                bb_error_msg_and_die("maximum excludes %d exceeded", MAX_EXCLUDES);
        }

        len = strlen(directory);
        while (len > 1 && directory[len - 1] == '/') {
                len--;
        }
        excludeArray[excludeCtr].directory = xstrndup(directory, len);
        excludeArray[excludeCtr++].size = len;
}

static bool exclude(const char *file)
{
        int i = 0;
        for (i = 0; i < excludeCtr; i++) {
                if (strncmp(file, excludeArray[i].directory,
                                        excludeArray[i].size) == 0) {
                        if (file[excludeArray[i].size] == '\0'
                         || file[excludeArray[i].size] == '/') {
                                return 1;
                        }
                }
        }
        return 0;
}

static int match(const char *name, struct stat *sb, char **con)
{
        int ret;
        char path[PATH_MAX + 1];
        char *tmp_path = xstrdup(name);

        if (excludeCtr > 0 && exclude(name)) {
                goto err;
        }
        ret = lstat(name, sb);
        if (ret) {
                if (FLAG_i_ignore_enoent && errno == ENOENT) {
                        free(tmp_path);
                        return 0;
                }
                bb_error_msg("stat(%s)", name);
                goto err;
        }

        if (expand_realpath) {
                if (S_ISLNK(sb->st_mode)) {
                        char *p = NULL;
                        char *file_sep;

                        size_t len = 0;

                        if (verbose > 1)
                                bb_error_msg("warning! %s refers to a symbolic link, not following last component", name);

                        file_sep = strrchr(tmp_path, '/');
                        if (file_sep == tmp_path) {
                                file_sep++;
                                path[0] = '\0';
                                p = path;
                        } else if (file_sep) {
                                *file_sep++ = '\0';
                                p = realpath(tmp_path, path);
                        } else {
                                file_sep = tmp_path;
                                p = realpath("./", path);
                        }
                        if (p)
                                len = strlen(p);
                        if (!p || len + strlen(file_sep) + 2 > PATH_MAX) {
                                bb_perror_msg("realpath(%s) failed", name);
                                goto err;
                        }
                        p += len;
                        /* ensure trailing slash of directory name */
                        if (len == 0 || p[-1] != '/') {
                                *p++ = '/';
                        }
                        strcpy(p, file_sep);
                        name = path;
                        if (excludeCtr > 0 && exclude(name))
                                goto err;
                } else {
                        char *p;
                        p = realpath(name, path);
                        if (!p) {
                                bb_perror_msg("realpath(%s)", name);
                                goto err;
                        }
                        name = p;
                        if (excludeCtr > 0 && exclude(name))
                                goto err;
                }
        }

        /* name will be what is matched in the policy */
        if (NULL != rootpath) {
                if (0 != strncmp(rootpath, name, rootpathlen)) {
                        bb_error_msg("%s is not located in %s",
                                name, rootpath);
                        goto err;
                }
                name += rootpathlen;
        }

        free(tmp_path);
        if (rootpath != NULL && name[0] == '\0')
                /* this is actually the root dir of the alt root */
                return matchpathcon_index("/", sb->st_mode, con);
        return matchpathcon_index(name, sb->st_mode, con);
 err:
        free(tmp_path);
        return -1;
}

/* Compare two contexts to see if their differences are "significant",
 * or whether the only difference is in the user. */
static bool only_changed_user(const char *a, const char *b)
{
        if (FLAG_F_force)
                return 0;
        if (!a || !b)
                return 0;
        a = strchr(a, ':'); /* Rest of the context after the user */
        b = strchr(b, ':');
        if (!a || !b)
                return 0;
        return (strcmp(a, b) == 0);
}

static int restore(const char *file)
{
        char *my_file;
        struct stat my_sb;
        int i, j, ret;
        char *context = NULL;
        char *newcon = NULL;
        bool user_only_changed = 0;
        int retval = 0;

        my_file = bb_simplify_path(file);

        i = match(my_file, &my_sb, &newcon);

        if (i < 0) /* No matching specification. */
                goto out;

        if (FLAG_p_progress) {
                count++;
                if (count % 0x400 == 0) { /* every 1024 times */
                        count = (count % (80*0x400));
                        if (count == 0)
                                bb_putchar('\n');
                        bb_putchar('*');
                        fflush_all();
                }
        }

        /*
         * Try to add an association between this inode and
         * this specification. If there is already an association
         * for this inode and it conflicts with this specification,
         * then use the last matching specification.
         */
        if (add_assoc) {
                j = matchpathcon_filespec_add(my_sb.st_ino, i, my_file);
                if (j < 0)
                        goto err;

                if (j != i) {
                        /* There was already an association and it took precedence. */
                        goto out;
                }
        }

        if (FLAG_d_debug)
                printf("%s: %s matched by %s\n", applet_name, my_file, newcon);

        /* Get the current context of the file. */
        ret = lgetfilecon_raw(my_file, &context);
        if (ret < 0) {
                if (errno == ENODATA) {
                        context = NULL; /* paranoia */
                } else {
                        bb_perror_msg("lgetfilecon_raw on %s", my_file);
                        goto err;
                }
                user_only_changed = 0;
        } else
                user_only_changed = only_changed_user(context, newcon);

        /*
         * Do not relabel the file if the matching specification is
         * <<none>> or the file is already labeled according to the
         * specification.
         */
        if ((strcmp(newcon, "<<none>>") == 0)
         || (context && (strcmp(context, newcon) == 0) && !FLAG_F_force)) {
                goto out;
        }

        if (!FLAG_F_force && context && (is_context_customizable(context) > 0)) {
                if (verbose > 1) {
                        bb_error_msg("skipping %s. %s is customizable_types",
                                my_file, context);
                }
                goto out;
        }

        if (verbose) {
                /* If we're just doing "-v", trim out any relabels where
                 * the user has changed but the role and type are the
                 * same.  For "-vv", emit everything. */
                if (verbose > 1 || !user_only_changed) {
                        printf("%s: reset %s context %s->%s\n",
                                applet_name, my_file, context ? context : "", newcon);
                }
        }

        if (FLAG_l_take_log && !user_only_changed) {
                if (context)
                        printf("relabeling %s from %s to %s\n", my_file, context, newcon);
                else
                        printf("labeling %s to %s\n", my_file, newcon);
        }

        if (outfile && !user_only_changed)
                fprintf(outfile, "%s\n", my_file);

        /*
         * Do not relabel the file if -n was used.
         */
        if (FLAG_n_dry_run || user_only_changed)
                goto out;

        /*
         * Relabel the file to the specified context.
         */
        ret = lsetfilecon(my_file, newcon);
        if (ret) {
                bb_perror_msg("lsetfileconon(%s,%s)", my_file, newcon);
                goto err;
        }

 out:
        freecon(context);
        freecon(newcon);
        free(my_file);
        return retval;
 err:
        retval--; /* -1 */
        goto out;
}

/*
 * Apply the last matching specification to a file.
 * This function is called by recursive_action on each file during
 * the directory traversal.
 */
static int FAST_FUNC apply_spec(
                const char *file,
                struct stat *sb,
                void *userData UNUSED_PARAM,
                int depth UNUSED_PARAM)
{
        if (!follow_mounts) {
                /* setfiles does not process across different mount points */
                if (sb->st_dev != dev_id) {
                        return SKIP;
                }
        }
        errors |= restore(file);
        if (abort_on_error && errors)
                return FALSE;
        return TRUE;
}


static int canoncon(const char *path, unsigned lineno, char **contextp)
{
        static const char err_msg[] ALIGN1 = "%s: line %u has invalid context %s";

        char *tmpcon;
        char *context = *contextp;
        int invalid = 0;

#if ENABLE_FEATURE_SETFILES_CHECK_OPTION
        if (policyfile) {
                if (sepol_check_context(context) >= 0)
                        return 0;
                /* Exit immediately if we're in checking mode. */
                bb_error_msg_and_die(err_msg, path, lineno, context);
        }
#endif

        if (security_canonicalize_context_raw(context, &tmpcon) < 0) {
                if (errno != ENOENT) {
                        invalid = 1;
                        inc_err();
                }
        } else {
                free(context);
                *contextp = tmpcon;
        }

        if (invalid) {
                bb_error_msg(err_msg, path, lineno, context);
        }

        return invalid;
}

static int process_one(char *name)
{
        struct stat sb;
        int rc;

        rc = lstat(name, &sb);
        if (rc < 0) {
                if (FLAG_i_ignore_enoent && errno == ENOENT)
                        return 0;
                bb_perror_msg("stat(%s)", name);
                goto err;
        }
        dev_id = sb.st_dev;

        if (S_ISDIR(sb.st_mode) && recurse) {
                if (recursive_action(name,
                                ACTION_RECURSE,
                                apply_spec,
                                apply_spec,
                                NULL, 0) != TRUE
                ) {
                        bb_error_msg("error while labeling %s", name);
                        goto err;
                }
        } else {
                rc = restore(name);
                if (rc)
                        goto err;
        }

 out:
        if (add_assoc) {
                if (FLAG_q_quiet)
                        set_matchpathcon_printf(&qprintf);
                matchpathcon_filespec_eval();
                set_matchpathcon_printf(NULL);
                matchpathcon_filespec_destroy();
        }

        return rc;

 err:
        rc = -1;
        goto out;
}

int setfiles_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int setfiles_main(int argc UNUSED_PARAM, char **argv)
{
        struct stat sb;
        int rc, i = 0;
        const char *input_filename = NULL;
        char *buf = NULL;
        size_t buf_len;
        int flags;
        llist_t *exclude_dir = NULL;
        char *out_filename = NULL;

        INIT_G();

        if (applet_name[0] == 's') { /* "setfiles" */
                /*
                 * setfiles:
                 * Recursive descent,
                 * Does not expand paths via realpath,
                 * Aborts on errors during the file tree walk,
                 * Try to track inode associations for conflict detection,
                 * Does not follow mounts,
                 * Validates all file contexts at init time.
                 */
                recurse = 1;
                abort_on_error = 1;
                add_assoc = 1;
                /* follow_mounts = 0; - already is */
                matchpathcon_flags = MATCHPATHCON_VALIDATE | MATCHPATHCON_NOTRANS;
        } else {
                /*
                 * restorecon:
                 * No recursive descent unless -r/-R,
                 * Expands paths via realpath,
                 * Do not abort on errors during the file tree walk,
                 * Do not try to track inode associations for conflict detection,
                 * Follows mounts,
                 * Does lazy validation of contexts upon use.
                 */
                expand_realpath = 1;
                follow_mounts = 1;
                matchpathcon_flags = MATCHPATHCON_NOTRANS;
                /* restorecon only */
                selinux_or_die();
        }

        set_matchpathcon_flags(matchpathcon_flags);

        opt_complementary = "vv:v--p:p--v:v--q:q--v";
        /* Option order must match OPT_x definitions! */
        if (applet_name[0] == 'r') { /* restorecon */
                flags = getopt32(argv, "de:*f:ilnpqrsvo:FWR",
                        &exclude_dir, &input_filename, &out_filename, &verbose);
        } else { /* setfiles */
                flags = getopt32(argv, "de:*f:ilnpqr:svo:FW"
                                IF_FEATURE_SETFILES_CHECK_OPTION("c:"),
                        &exclude_dir, &input_filename, &rootpath, &out_filename,
                                IF_FEATURE_SETFILES_CHECK_OPTION(&policyfile,)
                        &verbose);
        }
        argv += optind;

#if ENABLE_FEATURE_SETFILES_CHECK_OPTION
        if ((applet_name[0] == 's') && (flags & OPT_c)) {
                FILE *policystream;

                policystream = xfopen_for_read(policyfile);
                if (sepol_set_policydb_from_file(policystream) < 0) {
                        bb_error_msg_and_die("sepol_set_policydb_from_file on %s", policyfile);
                }
                fclose(policystream);

                /* Only process the specified file_contexts file, not
                 * any .homedirs or .local files, and do not perform
                 * context translations. */
                set_matchpathcon_flags(MATCHPATHCON_BASEONLY |
                                       MATCHPATHCON_NOTRANS |
                                       MATCHPATHCON_VALIDATE);
        }
#endif

        while (exclude_dir)
                add_exclude(llist_pop(&exclude_dir));

        if (flags & OPT_o) {
                outfile = stdout;
                if (NOT_LONE_CHAR(out_filename, '-')) {
                        outfile = xfopen_for_write(out_filename);
                }
        }
        if (applet_name[0] == 'r') { /* restorecon */
                if (flags & (OPT_r | OPT_R))
                        recurse = 1;
        } else { /* setfiles */
                if (flags & OPT_r)
                        rootpathlen = strlen(rootpath);
        }
        if (flags & OPT_s) {
                input_filename = "-";
                add_assoc = 0;
        }

        if (applet_name[0] == 's') { /* setfiles */
                /* Use our own invalid context checking function so that
                 * we can support either checking against the active policy or
                 * checking against a binary policy file. */
                set_matchpathcon_canoncon(&canoncon);
                if (!argv[0])
                        bb_show_usage();
                xstat(argv[0], &sb);
                if (!S_ISREG(sb.st_mode)) {
                        bb_error_msg_and_die("spec file %s is not a regular file", argv[0]);
                }
                /* Load the file contexts configuration and check it. */
                rc = matchpathcon_init(argv[0]);
                if (rc < 0) {
                        bb_simple_perror_msg_and_die(argv[0]);
                }
                if (nerr)
                        exit(EXIT_FAILURE);
                argv++;
        }

        if (input_filename) {
                ssize_t len;
                FILE *f = stdin;

                if (NOT_LONE_CHAR(input_filename, '-'))
                        f = xfopen_for_read(input_filename);
                while ((len = getline(&buf, &buf_len, f)) > 0) {
                        buf[len - 1] = '\0';
                        errors |= process_one(buf);
                }
                if (ENABLE_FEATURE_CLEAN_UP)
                        fclose_if_not_stdin(f);
        } else {
                if (!argv[0])
                        bb_show_usage();
                for (i = 0; argv[i]; i++) {
                        errors |= process_one(argv[i]);
                }
        }

        if (FLAG_W_warn_no_match)
                matchpathcon_checkmatches(argv[0]);

        if (ENABLE_FEATURE_CLEAN_UP && outfile)
                fclose(outfile);

        return errors;
}