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

   1 /* -*-c-*-
   2  *
   3  * $Id: chkpath.c,v 1.4 2004/04/08 01:36:22 mdw Exp $
   4  *
   5  * Check a user's file search path
   6  *
   7  * (c) 1999 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of chkpath.
  13  *
  14  * chkpath is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * chkpath is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with chkpath; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Header files ------------------------------------------------------*/
  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 static void report(unsigned what, int verbose,
  47                    const char *p, const char *msg,
  48                    void *arg)
  49 {
  50   moan("%s", msg);
  51 }
  52
  53 /* --- @usage@ --- */
  54
  55 static void usage(FILE *fp)
  56 {
  57   fprintf(fp, "Usage: %s [-vqstp] [PATH...]\n", QUIS);
  58 }
  59
  60 /* --- @version@ --- */
  61
  62 static void version(FILE *fp)
  63 {
  64   fprintf(fp, "%s version %s\n", QUIS, VERSION);
  65 }
  66
  67 /* --- @help@ --- */
  68
  69 static void help(FILE *fp)
  70 {
  71   version(fp);
  72   putc('\n', fp);
  73   usage(fp);
  74   fputs("\n\
  75 Checks a path string (by default the PATH variable) for security.  It\n\
  76 ensures that only `root' or the calling user can write to all the parent\n\
  77 directories of the path elements, so nobody can maliciously replace the\n\
  78 binaries unexpectedly.\n\
  79 \n\
  80 Options provided are:\n\
  81 \n\
  82 -h, --help              Display this help message.\n\
  83 -V, --version           Display the program's version number.\n\
  84 -u, --usage             Show a terse usage summary.\n\
  85 \n\
  86 -v, --verbose           Be verbose about the search progress (cumulative).\n\
  87 -q, --quiet             Be quiet about the search progress (cumulative).\n\
  88 -s, --sticky            Consider sticky directories secure against\n\
  89                         modification by world and group (not recommended).\n\
  90 -t, --trust-group       Consider other members of your group trustworthy.\n\
  91 -p, --print             Write the secure path elements to standard output.\n\
  92 ",
  93         fp);
  94 }
  95
  96 int main(int argc, char *argv[])
  97 {
  98   unsigned bad = 0;
  99   int i;
 100   char *p, *q, *path;
 101   struct checkpath cp;
 102   int f = 0;
 103
 104 #define f_print 1u
 105 #define f_colon 2u
 106
 107   /* --- Initialize the world --- */
 108
 109   ego(argv[0]);
 110
 111   /* --- Set up path scanning defaults --- */
 112
 113   cp.cp_verbose = 1;
 114   cp.cp_what = CP_PROBLEMS | CP_REPORT | CP_SYMLINK;
 115   cp.cp_report = report;
 116   cp.cp_arg = 0;
 117   checkpath_setids(&cp);
 118
 119   /* --- Parse the options --- */
 120
 121   for (;;) {
 122     static struct option opts[] = {
 123       { "help",         0,              0,      'h' },
 124       { "version",      0,              0,      'V' },
 125       { "usage",        0,              0,      'u' },
 126       { "verbose",      0,              0,      'v' },
 127       { "quiet",        0,              0,      'q' },
 128       { "sticky",       0,              0,      's' },
 129       { "trust-group",  0,              0,      't' },
 130       { "print",        0,              0,      'p' },
 131       { 0,              0,              0,      0 }
 132     };
 133     int i = mdwopt(argc, argv, "hVu vqstp", opts, 0, 0, 0);
 134
 135     if (i < 0)
 136       break;
 137     switch (i) {
 138       case 'h':
 139         help(stdout);
 140         exit(0);
 141       case 'V':
 142         version(stdout);
 143         exit(0);
 144       case 'u':
 145         usage(stdout);
 146         exit(0);
 147       case 'v':
 148         cp.cp_verbose++;
 149         break;
 150       case 'q':
 151         if (cp.cp_verbose)
 152           cp.cp_verbose--;
 153         break;
 154       case 's':
 155         cp.cp_what |= CP_STICKYOK;
 156         break;
 157       case 't':
 158         cp.cp_what = (cp.cp_what & ~CP_WRGRP) | CP_WROTHGRP;
 159         break;
 160       case 'p':
 161         f |= f_print;
 162         break;
 163       default:
 164         bad = 1;
 165         break;
 166     }
 167   }
 168
 169   if (bad) {
 170     usage(stderr);
 171     exit(1);
 172   }
 173
 174   /* --- Sort out what needs doing --- */
 175
 176   if (optind == argc) {
 177     path = getenv("PATH");
 178     argv = &path;
 179     argc = 1;
 180     optind = 0;
 181   }
 182
 183   for (i = optind; i < argc; i++) {
 184     p = xstrdup(argv[i]);
 185     q = strtok(p, ":");
 186     while (q) {
 187       unsigned b = checkpath(q, &cp);
 188       if (!b && (f & f_print)) {
 189         if (f & f_colon)
 190           putchar(':');
 191         fputs(q, stdout);
 192         f |= f_colon;
 193       }
 194       bad |= b;
 195       q = strtok(0, ":");
 196     }
 197     free(p);
 198   }
 199
 200   if (f & f_colon)
 201     putchar('\n');
 202
 203   return (bad);
 204 }
 205
 206 /*----- That's all, folks -------------------------------------------------*/