92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
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/*
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* =====================================================================================
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*
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* Filename: app.c
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*
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* Description: playing with finding writable files or directories on the host
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*
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* Version: 1.0
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* Created: 10/20/2023 06:41:29 PM
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* Revision: none
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* Compiler: gcc
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*
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* Author: Vincent Batts <vbatts@hashbangbash.com>
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*
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* =====================================================================================
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*/
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#define _XOPEN_SOURCE 500
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#include <ftw.h>
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#include <linux/limits.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <limits.h>
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uid_t uid;
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gid_t gid;
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int ngroups;
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gid_t groups[NGROUPS_MAX];
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int
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check_dir(const char *fpath, const struct stat *sb,
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int typeflag, struct FTW *ftwbuf) {
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int finding = 0;
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if (sb->st_uid != uid && sb->st_mode & S_IWOTH)
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finding |= 1;
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if (sb->st_uid != uid && sb->st_gid == gid && sb->st_mode & S_IWGRP)
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finding |= 2;
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for (int i = 0; i < ngroups; i++) {
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if (sb->st_uid != uid && sb->st_gid == groups[i] && sb->st_mode & S_IWGRP)
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finding |= 4;
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}
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if (typeflag == FTW_SLN || typeflag == FTW_SL)
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return 0;
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if (finding != 0) {
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printf("--> %s (m: %jo; t: %s; uid: %d; gid: %d)\n", fpath,
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(uintmax_t) sb->st_mode,
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(typeflag == FTW_D) ? "d" : (typeflag == FTW_F) ? "f" :
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(typeflag == FTW_SL) ? "sl" : (typeflag == FTW_SLN) ? "sln" : "???",
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sb->st_uid,
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sb->st_gid);
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if (finding&1)
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printf(" owned by another user and is world writable\n");
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if (finding&2)
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printf(" owned by another user and is group writable by our group\n");
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if (finding&4)
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printf(" owned by another user and is group writable by a group we are a member of\n");
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}
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return EXIT_SUCCESS;
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}
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int
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main(int argc, char** argv) {
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uid = geteuid();
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gid = getegid();
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ngroups = getgroups(NGROUPS_MAX, groups);
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int flags = 0;
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flags |= FTW_PHYS; // don't follow symlinks
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for (int i = 1; i < argc; i++) {
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printf("arg[%d] %s\n", i, argv[i]);
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int ret;
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ret = nftw(argv[i], &check_dir, 1024, flags);
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if (ret != EXIT_SUCCESS) {
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printf("FAILURE walking %s\n", argv[i]);
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}
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}
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return EXIT_SUCCESS;
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}
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