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 <pwd.h>
  38 #include <grp.h>
  39
  40 #include <mLib/alloc.h>
  41 #include <mLib/mdwopt.h>
  42 #include <mLib/quis.h>
  43 #include <mLib/report.h>
  44
  45 #include "checkpath.h"
  46 #include "utils.h"
  47
  48 /*----- Main code ---------------------------------------------------------*/
  49
  50 /* --- @report@ --- */
  51
  52 static void report(unsigned what, int verbose,
  53                    const char *p, const char *msg,
  54                    void *arg)
  55   { moan("%s", msg); }
  56
  57 /* --- @usage@ --- */
  58
  59 static void usage(FILE *fp)
  60   { fprintf(fp, "Usage: %s [-vqstp] [-g NAME] [PATH...]\n", QUIS); }
  61
  62 /* --- @version@ --- */
  63
  64 static void version(FILE *fp)
  65   { fprintf(fp, "%s version %s\n", QUIS, VERSION); }
  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 -g, --group NAME        Consider members of group NAME trustworthy.\n\
  92 -p, --print             Write the secure path elements to standard output.\n\
  93 ",
  94         fp);
  95 }
  96
  97 int main(int argc, char *argv[])
  98 {
  99   unsigned bad = 0;
 100   int i;
 101   char *p, *q, *path;
 102   struct checkpath cp;
 103   int f = 0;
 104
 105 #define f_print 1u
 106 #define f_colon 2u
 107
 108   /* --- Initialize the world --- */
 109
 110   ego(argv[0]);
 111
 112   /* --- Set up path scanning defaults --- */
 113
 114   cp.cp_verbose = 1;
 115   cp.cp_what = (CP_PROBLEMS | CP_REPORT | CP_SYMLINK) & ~CP_WRGRP;
 116   cp.cp_report = report;
 117   cp.cp_arg = 0;
 118   cp.cp_gids = 0;
 119   checkpath_setuid(&cp);
 120
 121   /* --- Parse the options --- */
 122
 123   for (;;) {
 124     static struct option opts[] = {
 125       { "help",         0,              0,      'h' },
 126       { "version",      0,              0,      'V' },
 127       { "usage",        0,              0,      'u' },
 128       { "verbose",      0,              0,      'v' },
 129       { "quiet",        0,              0,      'q' },
 130       { "sticky",       0,              0,      's' },
 131       { "trust-group",  0,              0,      't' },
 132       { "print",        0,              0,      'p' },
 133       { 0,              0,              0,      0 }
 134     };
 135     int i = mdwopt(argc, argv, "hVu" "vqstpg:", opts, 0, 0, 0);
 136
 137     if (i < 0)
 138       break;
 139     switch (i) {
 140       case 'h':
 141         help(stdout);
 142         exit(0);
 143       case 'V':
 144         version(stdout);
 145         exit(0);
 146       case 'u':
 147         usage(stdout);
 148         exit(0);
 149       case 'v':
 150         cp.cp_verbose++;
 151         break;
 152       case 'q':
 153         if (cp.cp_verbose)
 154           cp.cp_verbose--;
 155         break;
 156       case 's':
 157         cp.cp_what |= CP_STICKYOK;
 158         break;
 159       case 't':
 160         if (checkpath_setgid(&cp) || checkpath_setgroups(&cp))
 161           die(1, "too many groups");
 162         break;
 163       case 'g':
 164         allowgroup(&cp, optarg);
 165         break;
 166       case 'p':
 167         f |= f_print;
 168         break;
 169       default:
 170         bad = 1;
 171         break;
 172     }
 173   }
 174
 175   if (bad) {
 176     usage(stderr);
 177     exit(1);
 178   }
 179
 180   /* --- Sort out what needs doing --- */
 181
 182   if (optind == argc) {
 183     path = getenv("PATH");
 184     argv = &path;
 185     argc = 1;
 186     optind = 0;
 187   }
 188
 189   for (i = optind; i < argc; i++) {
 190     p = xstrdup(argv[i]);
 191     q = strtok(p, ":");
 192     while (q) {
 193       unsigned b = checkpath(q, &cp);
 194       if (!b && (f & f_print)) {
 195         if (f & f_colon)
 196           putchar(':');
 197         fputs(q, stdout);
 198         f |= f_colon;
 199       }
 200       bad |= b;
 201       q = strtok(0, ":");
 202     }
 203     free(p);
 204   }
 205
 206   if (f & f_colon)
 207     putchar('\n');
 208
 209   return (bad);
 210 }
 211
 212 /*----- That's all, folks -------------------------------------------------*/