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
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 /* --- @report@ --- */
  50
  51 static void report(unsigned what, int verbose,
  52                    const char *p, const char *msg,
  53                    void *arg)
  54   { moan("%s", msg); }
  55
  56 /* --- @usage@ --- */
  57
  58 static void usage(FILE *fp)
  59   { fprintf(fp, "Usage: %s [-vqstp] [-g NAME] [PATH...]\n", QUIS); }
  60
  61 /* --- @version@ --- */
  62
  63 static void version(FILE *fp)
  64   { fprintf(fp, "%s version %s\n", QUIS, VERSION); }
  65
  66 /* --- @help@ --- */
  67
  68 static void help(FILE *fp)
  69 {
  70   version(fp);
  71   putc('\n', fp);
  72   usage(fp);
  73   fputs("\n\
  74 Checks a path string (by default the PATH variable) for security.  It\n\
  75 ensures that only `root' or the calling user can write to all the parent\n\
  76 directories of the path elements, so nobody can maliciously replace the\n\
  77 binaries unexpectedly.\n\
  78 \n\
  79 Options provided are:\n\
  80 \n\
  81 -h, --help              Display this help message.\n\
  82 -V, --version           Display the program's version number.\n\
  83 -u, --usage             Show a terse usage summary.\n\
  84 \n\
  85 -v, --verbose           Be verbose about the search progress (cumulative).\n\
  86 -q, --quiet             Be quiet about the search progress (cumulative).\n\
  87 -s, --sticky            Consider sticky directories secure against\n\
  88                         modification by world and group (not recommended).\n\
  89 -t, --trust-group       Consider other members of your group trustworthy.\n\
  90 -g, --group NAME        Consider members of group NAME 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) & ~CP_WRGRP;
 115   cp.cp_report = report;
 116   cp.cp_arg = 0;
 117   cp.cp_gids = 0;
 118   checkpath_setuid(&cp);
 119
 120   /* --- Parse the options --- */
 121
 122   for (;;) {
 123     static struct option opts[] = {
 124       { "help",         0,              0,      'h' },
 125       { "version",      0,              0,      'V' },
 126       { "usage",        0,              0,      'u' },
 127       { "verbose",      0,              0,      'v' },
 128       { "quiet",        0,              0,      'q' },
 129       { "sticky",       0,              0,      's' },
 130       { "trust-group",  0,              0,      't' },
 131       { "print",        0,              0,      'p' },
 132       { 0,              0,              0,      0 }
 133     };
 134     int i = mdwopt(argc, argv, "hVu" "vqstpg:", opts, 0, 0, 0);
 135
 136     if (i < 0)
 137       break;
 138     switch (i) {
 139       case 'h':
 140         help(stdout);
 141         exit(0);
 142       case 'V':
 143         version(stdout);
 144         exit(0);
 145       case 'u':
 146         usage(stdout);
 147         exit(0);
 148       case 'v':
 149         cp.cp_verbose++;
 150         break;
 151       case 'q':
 152         if (cp.cp_verbose)
 153           cp.cp_verbose--;
 154         break;
 155       case 's':
 156         cp.cp_what |= CP_STICKYOK;
 157         break;
 158       case 't':
 159         if (checkpath_setgid(&cp) || checkpath_setgroups(&cp))
 160           die(1, "too many groups");
 161         break;
 162       case 'g':
 163         allowgroup(&cp, optarg);
 164         break;
 165       case 'p':
 166         f |= f_print;
 167         break;
 168       default:
 169         bad = 1;
 170         break;
 171     }
 172   }
 173
 174   if (bad) {
 175     usage(stderr);
 176     exit(1);
 177   }
 178
 179   /* --- Sort out what needs doing --- */
 180
 181   if (optind == argc) {
 182     path = getenv("PATH");
 183     argv = &path;
 184     argc = 1;
 185     optind = 0;
 186   }
 187
 188   for (i = optind; i < argc; i++) {
 189     p = xstrdup(argv[i]);
 190     q = strtok(p, ":");
 191     while (q) {
 192       unsigned b = checkpath(q, &cp);
 193       if (!b && (f & f_print)) {
 194         if (f & f_colon)
 195           putchar(':');
 196         fputs(q, stdout);
 197         f |= f_colon;
 198       }
 199       bad |= b;
 200       q = strtok(0, ":");
 201     }
 202     free(p);
 203   }
 204
 205   if (f & f_colon)
 206     putchar('\n');
 207
 208   return (bad);
 209 }
 210
 211 /*----- That's all, folks -------------------------------------------------*/