mdw@git.distorted.org.uk Git - checkpath/blob - chkpath.c

   1 /* -*-c-*-
   2  *
   3  * Check a user's file search path
   4  *
   5  * (c) 1999 Mark Wooding
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of chkpath.
  11  *
  12  * chkpath is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * chkpath is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with chkpath; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 /*----- Header files ------------------------------------------------------*/
  28
  29 #include "config.h"
  30
  31 #include <errno.h>
  32 #include <limits.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include <mLib/alloc.h>
  38 #include <mLib/mdwopt.h>
  39 #include <mLib/quis.h>
  40 #include <mLib/report.h>
  41
  42 #include "checkpath.h"
  43
  44 /*----- Main code ---------------------------------------------------------*/
  45
  46 /* --- @report@ --- */
  47
  48 static void report(unsigned what, int verbose,
  49                    const char *p, const char *msg,
  50                    void *arg)
  51   { moan("%s", msg); }
  52
  53 /* --- @usage@ --- */
  54
  55 static void usage(FILE *fp)
  56   { fprintf(fp, "Usage: %s [-vqstp] [PATH...]\n", QUIS); }
  57
  58 /* --- @version@ --- */
  59
  60 static void version(FILE *fp)
  61   { fprintf(fp, "%s version %s\n", QUIS, VERSION); }
  62
  63 /* --- @help@ --- */
  64
  65 static void help(FILE *fp)
  66 {
  67   version(fp);
  68   putc('\n', fp);
  69   usage(fp);
  70   fputs("\n\
  71 Checks a path string (by default the PATH variable) for security.  It\n\
  72 ensures that only `root' or the calling user can write to all the parent\n\
  73 directories of the path elements, so nobody can maliciously replace the\n\
  74 binaries unexpectedly.\n\
  75 \n\
  76 Options provided are:\n\
  77 \n\
  78 -h, --help              Display this help message.\n\
  79 -V, --version           Display the program's version number.\n\
  80 -u, --usage             Show a terse usage summary.\n\
  81 \n\
  82 -v, --verbose           Be verbose about the search progress (cumulative).\n\
  83 -q, --quiet             Be quiet about the search progress (cumulative).\n\
  84 -s, --sticky            Consider sticky directories secure against\n\
  85                         modification by world and group (not recommended).\n\
  86 -t, --trust-group       Consider other members of your group trustworthy.\n\
  87 -p, --print             Write the secure path elements to standard output.\n\
  88 ",
  89         fp);
  90 }
  91
  92 int main(int argc, char *argv[])
  93 {
  94   unsigned bad = 0;
  95   int i;
  96   char *p, *q, *path;
  97   struct checkpath cp;
  98   int f = 0;
  99
 100 #define f_print 1u
 101 #define f_colon 2u
 102
 103   /* --- Initialize the world --- */
 104
 105   ego(argv[0]);
 106
 107   /* --- Set up path scanning defaults --- */
 108
 109   cp.cp_verbose = 1;
 110   cp.cp_what = CP_PROBLEMS | CP_REPORT | CP_SYMLINK;
 111   cp.cp_report = report;
 112   cp.cp_arg = 0;
 113   checkpath_setids(&cp);
 114
 115   /* --- Parse the options --- */
 116
 117   for (;;) {
 118     static struct option opts[] = {
 119       { "help",         0,              0,      'h' },
 120       { "version",      0,              0,      'V' },
 121       { "usage",        0,              0,      'u' },
 122       { "verbose",      0,              0,      'v' },
 123       { "quiet",        0,              0,      'q' },
 124       { "sticky",       0,              0,      's' },
 125       { "trust-group",  0,              0,      't' },
 126       { "print",        0,              0,      'p' },
 127       { 0,              0,              0,      0 }
 128     };
 129     int i = mdwopt(argc, argv, "hVu" "vqstp", opts, 0, 0, 0);
 130
 131     if (i < 0)
 132       break;
 133     switch (i) {
 134       case 'h':
 135         help(stdout);
 136         exit(0);
 137       case 'V':
 138         version(stdout);
 139         exit(0);
 140       case 'u':
 141         usage(stdout);
 142         exit(0);
 143       case 'v':
 144         cp.cp_verbose++;
 145         break;
 146       case 'q':
 147         if (cp.cp_verbose)
 148           cp.cp_verbose--;
 149         break;
 150       case 's':
 151         cp.cp_what |= CP_STICKYOK;
 152         break;
 153       case 't':
 154         cp.cp_what = (cp.cp_what & ~CP_WRGRP) | CP_WROTHGRP;
 155         break;
 156       case 'p':
 157         f |= f_print;
 158         break;
 159       default:
 160         bad = 1;
 161         break;
 162     }
 163   }
 164
 165   if (bad) {
 166     usage(stderr);
 167     exit(1);
 168   }
 169
 170   /* --- Sort out what needs doing --- */
 171
 172   if (optind == argc) {
 173     path = getenv("PATH");
 174     argv = &path;
 175     argc = 1;
 176     optind = 0;
 177   }
 178
 179   for (i = optind; i < argc; i++) {
 180     p = xstrdup(argv[i]);
 181     q = strtok(p, ":");
 182     while (q) {
 183       unsigned b = checkpath(q, &cp);
 184       if (!b && (f & f_print)) {
 185         if (f & f_colon)
 186           putchar(':');
 187         fputs(q, stdout);
 188         f |= f_colon;
 189       }
 190       bad |= b;
 191       q = strtok(0, ":");
 192     }
 193     free(p);
 194   }
 195
 196   if (f & f_colon)
 197     putchar('\n');
 198
 199   return (bad);
 200 }
 201
 202 /*----- That's all, folks -------------------------------------------------*/