mirror of
git://git.gnupg.org/gnupg.git
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509d0f76ce
* tools/gpg-check-pattern.c (read_file): Check length before calling fread. -- The problem with an empty file is that es_fread is called to read one element of length zero which seems to be undefined behaviour and results in ENOENT on my test box.
634 lines
16 KiB
C
634 lines
16 KiB
C
/* gpg-check-pattern.c - A tool to check passphrases against pattern.
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* Copyright (C) 2021 g10 Code GmbH
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* Copyright (C) 2007 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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* SPDX-License-Identifier: GPL-3.0-or-later
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <stdarg.h>
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#include <string.h>
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#include <errno.h>
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#ifdef HAVE_LOCALE_H
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# include <locale.h>
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#endif
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#ifdef HAVE_LANGINFO_CODESET
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# include <langinfo.h>
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#endif
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#ifdef HAVE_DOSISH_SYSTEM
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# include <fcntl.h> /* for setmode() */
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#endif
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <ctype.h>
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#include "../common/util.h"
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#include "../common/i18n.h"
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#include "../common/sysutils.h"
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#include "../common/init.h"
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#include "../regexp/jimregexp.h"
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enum cmd_and_opt_values
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{ aNull = 0,
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oVerbose = 'v',
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oNull = '0',
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oNoVerbose = 500,
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oCheck,
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oHomedir
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};
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/* The list of commands and options. */
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static ARGPARSE_OPTS opts[] = {
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{ 301, NULL, 0, N_("@Options:\n ") },
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{ oVerbose, "verbose", 0, "verbose" },
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{ oHomedir, "homedir", 2, "@" },
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{ oCheck, "check", 0, "run only a syntax check on the patternfile" },
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{ oNull, "null", 0, "input is expected to be null delimited" },
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ARGPARSE_end ()
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};
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/* Global options are accessed through the usual OPT structure. */
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static struct
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{
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int verbose;
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const char *homedir;
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int checkonly;
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int null;
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} opt;
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enum {
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PAT_NULL, /* Indicates end of the array. */
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PAT_STRING, /* The pattern is a simple string. */
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PAT_REGEX /* The pattern is an extended regualr expression. */
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};
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/* An object to decibe an item of our pattern table. */
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struct pattern_s
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{
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int type;
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unsigned int lineno; /* Line number of the pattern file. */
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unsigned int newblock; /* First pattern in a new block. */
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unsigned int icase:1; /* Case insensitive match. */
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unsigned int accept:1; /* In accept mode. */
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unsigned int reverse:1; /* Reverse the outcome of a regexp match. */
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union {
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struct {
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const char *string; /* Pointer to the actual string (nul termnated). */
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size_t length; /* The length of this string (strlen). */
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} s; /*PAT_STRING*/
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struct {
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/* We allocate the regex_t because this type is larger than what
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we need for PAT_STRING and we expect only a few regex in a
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patternfile. It would be a waste of core to have so many
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unused stuff in the table. */
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regex_t *regex;
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} r; /*PAT_REGEX*/
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} u;
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};
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typedef struct pattern_s pattern_t;
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/*** Local prototypes ***/
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static char *read_file (const char *fname, size_t *r_length);
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static pattern_t *parse_pattern_file (char *data, size_t datalen);
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static void process (FILE *fp, pattern_t *patarray);
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/* Info function for usage(). */
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static const char *
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my_strusage (int level)
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{
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const char *p;
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switch (level)
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{
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case 9: p = "GPL-3.0-or-later"; break;
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case 11: p = "gpg-check-pattern (@GnuPG@)";
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break;
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case 13: p = VERSION; break;
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case 14: p = GNUPG_DEF_COPYRIGHT_LINE; break;
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case 17: p = PRINTABLE_OS_NAME; break;
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case 19: p = _("Please report bugs to <@EMAIL@>.\n"); break;
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case 1:
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case 40:
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p = _("Usage: gpg-check-pattern [options] patternfile (-h for help)\n");
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break;
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case 41:
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p = _("Syntax: gpg-check-pattern [options] patternfile\n"
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"Check a passphrase given on stdin against the patternfile\n");
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break;
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default: p = NULL;
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}
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return p;
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}
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int
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main (int argc, char **argv )
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{
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ARGPARSE_ARGS pargs;
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char *raw_pattern;
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size_t raw_pattern_length;
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pattern_t *patternarray;
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early_system_init ();
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set_strusage (my_strusage);
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gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
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log_set_prefix ("gpg-check-pattern", GPGRT_LOG_WITH_PREFIX);
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/* Make sure that our subsystems are ready. */
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i18n_init ();
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init_common_subsystems (&argc, &argv);
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setup_libgcrypt_logging ();
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gcry_control (GCRYCTL_INIT_SECMEM, 4096, 0);
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pargs.argc = &argc;
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pargs.argv = &argv;
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pargs.flags= ARGPARSE_FLAG_KEEP;
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while (gnupg_argparse (NULL, &pargs, opts))
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{
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switch (pargs.r_opt)
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{
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case oVerbose: opt.verbose++; break;
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case oHomedir: gnupg_set_homedir (pargs.r.ret_str); break;
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case oCheck: opt.checkonly = 1; break;
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case oNull: opt.null = 1; break;
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default : pargs.err = 2; break;
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}
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}
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gnupg_argparse (NULL, &pargs, NULL); /* Release internal state. */
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if (log_get_errorcount(0))
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exit (2);
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if (argc != 1)
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usage (1);
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/* We read the entire pattern file into our memory and parse it
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using a separate function. This allows us to eventually do the
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reading while running setuid so that the pattern file can be
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hidden from regular users. I am not sure whether this makes
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sense, but lets be prepared for it. */
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raw_pattern = read_file (*argv, &raw_pattern_length);
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if (!raw_pattern)
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exit (2);
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patternarray = parse_pattern_file (raw_pattern, raw_pattern_length);
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if (!patternarray)
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exit (1);
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if (opt.checkonly)
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return 0;
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#ifdef HAVE_DOSISH_SYSTEM
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setmode (fileno (stdin) , O_BINARY );
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#endif
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process (stdin, patternarray);
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return 4; /*NOTREACHED*/
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}
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/* Read a file FNAME into a buffer and return that malloced buffer.
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Caller must free the buffer. On error NULL is returned, on success
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the valid length of the buffer is stored at R_LENGTH. The returned
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buffer is guarnteed to be nul terminated. */
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static char *
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read_file (const char *fname, size_t *r_length)
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{
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estream_t fp;
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char *buf;
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size_t buflen;
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if (!strcmp (fname, "-"))
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{
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size_t nread, bufsize = 0;
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fp = es_stdin;
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es_set_binary (fp);
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buf = NULL;
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buflen = 0;
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#define NCHUNK 8192
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do
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{
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bufsize += NCHUNK;
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if (!buf)
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buf = xmalloc (bufsize+1);
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else
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buf = xrealloc (buf, bufsize+1);
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nread = es_fread (buf+buflen, 1, NCHUNK, fp);
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if (nread < NCHUNK && es_ferror (fp))
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{
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log_error ("error reading '[stdin]': %s\n", strerror (errno));
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xfree (buf);
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return NULL;
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}
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buflen += nread;
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}
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while (nread == NCHUNK);
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#undef NCHUNK
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}
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else
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{
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struct stat st;
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fp = es_fopen (fname, "rb");
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if (!fp)
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{
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log_error ("can't open '%s': %s\n", fname, strerror (errno));
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return NULL;
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}
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if (fstat (es_fileno (fp), &st))
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{
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log_error ("can't stat '%s': %s\n", fname, strerror (errno));
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es_fclose (fp);
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return NULL;
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}
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buflen = st.st_size;
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buf = xmalloc (buflen+1);
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if (buflen && es_fread (buf, buflen, 1, fp) != 1)
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{
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log_error ("error reading '%s': %s\n", fname, strerror (errno));
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es_fclose (fp);
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xfree (buf);
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return NULL;
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}
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es_fclose (fp);
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}
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buf[buflen] = 0;
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*r_length = buflen;
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return buf;
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}
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static char *
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get_regerror (int errcode, regex_t *compiled)
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{
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size_t length = regerror (errcode, compiled, NULL, 0);
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char *buffer = xmalloc (length);
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regerror (errcode, compiled, buffer, length);
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return buffer;
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}
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/* Parse the pattern given in the memory aread DATA/DATALEN and return
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a new pattern array. The end of the array is indicated by a NULL
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entry. On error an error message is printed and the function
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returns NULL. Note that the function modifies DATA and assumes
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that data is nul terminated (even if this is one byte past
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DATALEN). */
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static pattern_t *
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parse_pattern_file (char *data, size_t datalen)
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{
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char *p, *p2;
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size_t n;
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pattern_t *array;
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size_t arraysize, arrayidx;
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unsigned int lineno = 0;
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unsigned int icase_mode = 1;
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unsigned int accept_mode = 0;
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unsigned int newblock = 1; /* The first implict block. */
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/* Estimate the number of entries by counting the non-comment lines. */
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arraysize = 0;
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p = data;
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for (n = datalen; n && (p2 = memchr (p, '\n', n)); p2++, n -= p2 - p, p = p2)
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if (*p != '#')
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arraysize++;
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arraysize += 2; /* For the terminating NULL and a last line w/o a LF. */
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array = xcalloc (arraysize, sizeof *array);
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arrayidx = 0;
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/* Loop over all lines. */
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while (datalen && data)
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{
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lineno++;
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p = data;
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p2 = data = memchr (p, '\n', datalen);
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if (p2)
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{
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*data++ = 0;
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datalen -= data - p;
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}
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else
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p2 = p + datalen;
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log_assert (!*p2);
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p2--;
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while (isascii (*p) && isspace (*p))
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p++;
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if (*p == '#')
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continue;
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while (p2 > p && isascii (*p2) && isspace (*p2))
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*p2-- = 0;
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if (!*p)
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continue;
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if (!strcmp (p, "[case]"))
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{
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icase_mode = 0;
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continue;
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}
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if (!strcmp (p, "[icase]"))
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{
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icase_mode = 1;
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continue;
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}
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if (!strcmp (p, "[accept]"))
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{
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accept_mode = 1;
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newblock = 1;
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continue;
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}
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if (!strcmp (p, "[reject]"))
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{
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accept_mode = 0;
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newblock = 1;
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continue;
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}
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log_assert (arrayidx < arraysize);
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array[arrayidx].lineno = lineno;
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array[arrayidx].icase = icase_mode;
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array[arrayidx].accept = accept_mode;
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array[arrayidx].reverse = 0;
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array[arrayidx].newblock = newblock;
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newblock = 0;
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if (*p == '/' || (*p == '!' && p[1] == '/'))
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{
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int rerr;
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int reverse;
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reverse = (*p == '!');
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p++;
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if (reverse)
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p++;
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array[arrayidx].type = PAT_REGEX;
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if (*p && p[strlen(p)-1] == '/')
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p[strlen(p)-1] = 0; /* Remove optional delimiter. */
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array[arrayidx].u.r.regex = xcalloc (1, sizeof (regex_t));
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array[arrayidx].reverse = reverse;
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rerr = regcomp (array[arrayidx].u.r.regex, p,
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(array[arrayidx].icase? REG_ICASE:0)|REG_EXTENDED);
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if (rerr)
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{
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char *rerrbuf = get_regerror (rerr, array[arrayidx].u.r.regex);
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log_error ("invalid regexp at line %u: %s\n", lineno, rerrbuf);
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xfree (rerrbuf);
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if (!opt.checkonly)
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exit (1);
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}
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}
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else
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{
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if (*p == '[')
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{
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static int shown;
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if (!shown)
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{
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log_info ("future warning: do no start a string with '['"
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" but use a regexp (line %u)\n", lineno);
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shown = 1;
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}
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}
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array[arrayidx].type = PAT_STRING;
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array[arrayidx].u.s.string = p;
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array[arrayidx].u.s.length = strlen (p);
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}
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arrayidx++;
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}
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log_assert (arrayidx < arraysize);
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array[arrayidx].type = PAT_NULL;
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if (lineno && newblock)
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log_info ("warning: pattern list ends with a singleton"
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" accept or reject tag\n");
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return array;
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}
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/* Check whether string matches any of the pattern in PATARRAY and
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returns the matching pattern item or NULL. */
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static pattern_t *
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match_p (const char *string, pattern_t *patarray)
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{
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pattern_t *pat;
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int match;
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int accept_match; /* Tracks matchinf state in an accept block. */
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int accept_skip; /* Skip remaining patterns in an accept block. */
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if (!*string)
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{
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if (opt.verbose)
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log_info ("zero length input line - ignored\n");
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return NULL;
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}
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accept_match = 0;
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accept_skip = 0;
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for (pat = patarray; pat->type != PAT_NULL; pat++)
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{
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match = 0;
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if (pat->newblock)
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accept_match = accept_skip = 0;
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if (pat->type == PAT_STRING)
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{
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if (pat->icase)
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{
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if (!strcasecmp (pat->u.s.string, string))
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match = 1;
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}
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else
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{
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if (!strcmp (pat->u.s.string, string))
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match = 1;
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}
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}
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else if (pat->type == PAT_REGEX)
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{
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int rerr;
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rerr = regexec (pat->u.r.regex, string, 0, NULL, 0);
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if (pat->reverse)
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{
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if (!rerr)
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rerr = REG_NOMATCH;
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else if (rerr == REG_NOMATCH)
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rerr = 0;
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}
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if (!rerr)
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match = 1;
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else if (rerr != REG_NOMATCH)
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{
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char *rerrbuf = get_regerror (rerr, pat->u.r.regex);
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log_error ("matching regexp failed: %s\n", rerrbuf);
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xfree (rerrbuf);
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if (pat->accept)
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match = 0; /* Better indicate no match on error. */
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else
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match = 1; /* Better indicate a match on error. */
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}
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}
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else
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BUG ();
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if (pat->accept)
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{
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/* Accept mode: all patterns in the accept block must match.
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* Thus we need to check whether the next pattern has a
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* transition and act only then. */
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if (match && !accept_skip)
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accept_match = 1;
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else
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{
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accept_match = 0;
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accept_skip = 1;
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}
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if (pat[1].type == PAT_NULL || pat[1].newblock)
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{
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/* Transition detected. Note that this also handles the
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* end of pattern loop case. */
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if (accept_match)
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return pat;
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/* The next is not really but we do it for clarity. */
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accept_match = accept_skip = 0;
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}
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}
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else /* Reject mode: Return true on the first match. */
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{
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if (match)
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return pat;
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}
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}
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return NULL;
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}
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|
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/* Actual processing of the input. This function does not return an
|
||
error code but exits as soon as a match has been found. */
|
||
static void
|
||
process (FILE *fp, pattern_t *patarray)
|
||
{
|
||
char buffer[2048];
|
||
size_t idx;
|
||
int c;
|
||
unsigned long lineno = 0;
|
||
pattern_t *pat;
|
||
int last_is_accept;
|
||
|
||
idx = 0;
|
||
c = 0;
|
||
while (idx < sizeof buffer -1 && c != EOF )
|
||
{
|
||
if ((c = getc (fp)) != EOF)
|
||
buffer[idx] = c;
|
||
if ((c == '\n' && !opt.null) || (!c && opt.null) || c == EOF)
|
||
{
|
||
lineno++;
|
||
if (!opt.null)
|
||
{
|
||
while (idx && isascii (buffer[idx-1]) && isspace (buffer[idx-1]))
|
||
idx--;
|
||
}
|
||
buffer[idx] = 0;
|
||
pat = match_p (buffer, patarray);
|
||
if (pat)
|
||
{
|
||
/* Note that the accept mode works correctly only with
|
||
* one input line. */
|
||
if (opt.verbose)
|
||
log_info ("input line %lu matches pattern at line %u"
|
||
" - %s\n",
|
||
lineno, pat->lineno,
|
||
pat->accept? "accepted":"rejected");
|
||
}
|
||
idx = 0;
|
||
wipememory (buffer, sizeof buffer);
|
||
if (pat)
|
||
{
|
||
if (pat->accept)
|
||
exit (0);
|
||
else
|
||
exit (1);
|
||
}
|
||
}
|
||
else
|
||
idx++;
|
||
}
|
||
wipememory (buffer, sizeof buffer);
|
||
if (c != EOF)
|
||
{
|
||
log_error ("input line %lu too long - rejected\n", lineno+1);
|
||
exit (1);
|
||
}
|
||
if (ferror (fp))
|
||
{
|
||
log_error ("input read error at line %lu: %s - rejected\n",
|
||
lineno+1, strerror (errno));
|
||
exit (1);
|
||
}
|
||
|
||
/* Check last pattern to see whether we are in accept mode. */
|
||
last_is_accept = 0;
|
||
for (pat = patarray; pat->type != PAT_NULL; pat++)
|
||
last_is_accept = pat->accept;
|
||
|
||
if (opt.verbose)
|
||
log_info ("no input line matches the pattern - %s\n",
|
||
last_is_accept? "rejected":"accepted");
|
||
|
||
if (log_get_errorcount(0))
|
||
exit (2); /* Ooops - reject. */
|
||
else if (last_is_accept)
|
||
exit (1); /* Reject */
|
||
else
|
||
exit (0); /* Accept */
|
||
}
|