pgppubring.c

mutt-1.5.12 源代码。linux 下邮件接受的工具。

/*
 * Copyright (C) 1997-2001 Thomas Roessler <[e-mail]>
 * 
 *     This program is free software; you can redistribute it
 *     and/or modify it under the terms of the GNU General Public
 *     License as published by the Free Software Foundation; either
 *     version 2 of the License, or (at your option) any later
 *     version.
 * 
 *     This program is distributed in the hope that it will be
 *     useful, but WITHOUT ANY WARRANTY; without even the implied
 *     warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *     PURPOSE.  See the GNU General Public License for more
 *     details.
 * 
 *     You should have received a copy of the GNU General Public
 *     License along with this program; if not, write to the Free
 *     Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *     Boston, MA  02110-1301, USA.
 */

/*
 * This is a "simple" PGP key ring dumper.
 * 
 * The output format is supposed to be compatible to the one GnuPG
 * emits and Mutt expects.
 * 
 * Note that the code of this program could be considerably less
 * complex, but most of it was taken from mutt's second generation
 * key ring parser.
 * 
 * You can actually use this to put together some fairly general
 * PGP key management applications.
 *
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#ifdef HAVE_GETOPT_H
# include <getopt.h>
#endif
#include <errno.h>

extern char *optarg;
extern int optind;

#include "sha1.h"
#include "md5.h"
#include "lib.h"
#include "pgplib.h"
#include "pgppacket.h"

#define MD5_DIGEST_LENGTH  16

#ifdef HAVE_FGETPOS
#define FGETPOS(fp,pos) fgetpos((fp),&(pos))
#define FSETPOS(fp,pos) fsetpos((fp),&(pos))
#else
#define FGETPOS(fp,pos) pos=ftello((fp));
#define FSETPOS(fp,pos) fseeko((fp),(pos),SEEK_SET)
#endif


static short dump_signatures = 0;
static short dump_fingerprints = 0;


static void pgpring_find_candidates (char *ringfile, const char *hints[], int nhints);
static void pgpring_dump_keyblock (pgp_key_t p);

int main (int argc, char * const argv[])
{
  int c;
  
  short version = 2;
  short secring = 0;
  
  const char *_kring = NULL;
  char *env_pgppath, *env_home;

  char pgppath[_POSIX_PATH_MAX];
  char kring[_POSIX_PATH_MAX];

  while ((c = getopt (argc, argv, "f25sk:S")) != EOF)
  {
    switch (c)
    {
      case 'S':
      {
	dump_signatures = 1;
	break;
      }

      case 'f':
      {
	dump_fingerprints = 1;
	break;
      }

      case 'k':
      {
	_kring = optarg;
	break;
      }
      
      case '2': case '5':
      {
	version = c - '0';
	break;
      }
      
      case 's':
      {
	secring = 1;
	break;
      }
    
      default:
      {
	fprintf (stderr, "usage: %s [-k <key ring> | [-2 | -5] [ -s] [-S] [-f]] [hints]\n",
		 argv[0]);
	exit (1);
      }
    }
  }

  if (_kring)
    strfcpy (kring, _kring, sizeof (kring));
  else
  {
    if ((env_pgppath = getenv ("PGPPATH")))
      strfcpy (pgppath, env_pgppath, sizeof (pgppath));
    else if ((env_home = getenv ("HOME")))
      snprintf (pgppath, sizeof (pgppath), "%s/.pgp", env_home);
    else
    {
      fprintf (stderr, "%s: Can't determine your PGPPATH.\n", argv[0]);
      exit (1);
    }
    
    if (secring)
      snprintf (kring, sizeof (kring), "%s/secring.%s", pgppath, version == 2 ? "pgp" : "skr");
    else
      snprintf (kring, sizeof (kring), "%s/pubring.%s", pgppath, version == 2 ? "pgp" : "pkr");
  }
  
  pgpring_find_candidates (kring, (const char**) argv + optind, argc - optind);
    
  return 0;
}


/* The actual key ring parser */

static void pgp_make_pgp2_fingerprint (unsigned char *buff,
                                       unsigned char *digest)
{

  MD5_CTX context;
  unsigned int size = 0;


  MD5Init (&context);

  size = (buff[0] << 8) + buff[1];
  size = ((size + 7) / 8);
  buff = &buff[2];

  MD5Update (&context, buff, size);
  buff = &buff[size];

  size = (buff[0] << 8) + buff[1];
  size = ((size + 7) / 8);
  buff = &buff[2];

  MD5Update (&context, buff, size);

  MD5Final (digest, &context);

} /* pgp_make_pgp2_fingerprint() */

static pgp_key_t pgp_parse_pgp2_key (unsigned char *buff, size_t l)
{
  pgp_key_t p;
  unsigned char alg;
  unsigned char digest[MD5_DIGEST_LENGTH];
  size_t expl;
  unsigned long id;
  time_t gen_time = 0;
  unsigned short exp_days = 0;
  size_t j;
  int i, k;
  unsigned char scratch[LONG_STRING];

  if (l < 12)
    return NULL;

  p = pgp_new_keyinfo();

  for (i = 0, j = 2; i < 4; i++)
    gen_time = (gen_time << 8) + buff[j++];

  p->gen_time = gen_time;

  for (i = 0; i < 2; i++)
    exp_days = (exp_days << 8) + buff[j++];

  if (exp_days && time (NULL) > gen_time + exp_days * 24 * 3600)
    p->flags |= KEYFLAG_EXPIRED;

  alg = buff[j++];

  p->numalg = alg;
  p->algorithm = pgp_pkalgbytype (alg);
  p->flags |= pgp_get_abilities (alg);

  if (dump_fingerprints)
  {
    /* j now points to the key material, which we need for the fingerprint */
    p->fp_len = MD5_DIGEST_LENGTH;
    pgp_make_pgp2_fingerprint (&buff[j], digest);
    memcpy (p->fingerprint, digest, MD5_DIGEST_LENGTH);
  }
  else	/* just to be usre */
    memset (p->fingerprint, 0, MD5_DIGEST_LENGTH);
    
  expl = 0;
  for (i = 0; i < 2; i++)
    expl = (expl << 8) + buff[j++];

  p->keylen = expl;

  expl = (expl + 7) / 8;
  if (expl < 4)
    goto bailout;


  j += expl - 8;

  for (k = 0; k < 2; k++)
  {
    for (id = 0, i = 0; i < 4; i++)
      id = (id << 8) + buff[j++];

    snprintf ((char *) scratch + k * 8, sizeof (scratch) - k * 8,
	      "%08lX", id);
  }

  p->keyid = safe_strdup ((char *) scratch);

  return p;

bailout:

  FREE (&p);
  return NULL;
}

static void pgp_make_pgp3_fingerprint (unsigned char *buff, size_t l,
				       unsigned char *digest)
{
  unsigned char dummy;
  SHA1_CTX context;

  SHA1_Init (&context);

  dummy = buff[0] & 0x3f;

  if (dummy == PT_SUBSECKEY || dummy == PT_SUBKEY || dummy == PT_SECKEY)
    dummy = PT_PUBKEY;

  dummy = (dummy << 2) | 0x81;
  SHA1_Update (&context, &dummy, 1);
  dummy = ((l - 1) >> 8) & 0xff;
  SHA1_Update (&context, &dummy, 1);
  dummy = (l - 1) & 0xff;
  SHA1_Update (&context, &dummy, 1);
  SHA1_Update (&context, buff + 1, l - 1);
  SHA1_Final (digest, &context);

}

static void skip_bignum (unsigned char *buff, size_t l, size_t j,
			 size_t * toff, size_t n)
{
  size_t len;

  do
  {
    len = (buff[j] << 8) + buff[j + 1];
    j += (len + 7) / 8 + 2;
  }
  while (j <= l && --n > 0);

  if (toff)
    *toff = j;
}


static pgp_key_t pgp_parse_pgp3_key (unsigned char *buff, size_t l)
{
  pgp_key_t p;
  unsigned char alg;
  unsigned char digest[SHA_DIGEST_LENGTH];
  unsigned char scratch[LONG_STRING];
  time_t gen_time = 0;
  unsigned long id;
  int i, k;
  short len;
  size_t j;

  p = pgp_new_keyinfo ();
  j = 2;

  for (i = 0; i < 4; i++)
    gen_time = (gen_time << 8) + buff[j++];

  p->gen_time = gen_time;

  alg = buff[j++];

  p->numalg = alg;
  p->algorithm = pgp_pkalgbytype (alg);
  p->flags |= pgp_get_abilities (alg);

  if (alg == 17)
    skip_bignum (buff, l, j, &j, 3);
  else if (alg == 16 || alg == 20)
    skip_bignum (buff, l, j, &j, 2);

  len = (buff[j] << 8) + buff[j + 1];
  p->keylen = len;


  if (alg >= 1 && alg <= 3)
    skip_bignum (buff, l, j, &j, 2);
  else if (alg == 17 || alg == 16 || alg == 20)
    skip_bignum (buff, l, j, &j, 1);

  pgp_make_pgp3_fingerprint (buff, j, digest);
  p->fp_len = SHA_DIGEST_LENGTH;
  
  for (k = 0; k < 2; k++)
  {
    for (id = 0, i = SHA_DIGEST_LENGTH - 8 + k * 4;
	 i < SHA_DIGEST_LENGTH + (k - 1) * 4; i++)
      id = (id << 8) + digest[i];

    snprintf ((char *) scratch + k * 8, sizeof (scratch) - k * 8, "%08lX", id);
  }

  p->keyid = safe_strdup ((char *) scratch);

  return p;
}

static pgp_key_t pgp_parse_keyinfo (unsigned char *buff, size_t l)
{
  if (!buff || l < 2)
    return NULL;

  switch (buff[1])
  {
  case 2:
  case 3:
    return pgp_parse_pgp2_key (buff, l);
  case 4:
    return pgp_parse_pgp3_key (buff, l);
  default:
    return NULL;
  }
}

static int pgp_parse_pgp2_sig (unsigned char *buff, size_t l,
                               pgp_key_t p, pgp_sig_t *s)
{
  unsigned char sigtype;
  time_t sig_gen_time;
  unsigned long signerid1;
  unsigned long signerid2;
  size_t j;
  int i;

  if (l < 22)
    return -1;

  j = 3;
  sigtype = buff[j++];

  sig_gen_time = 0;
  for (i = 0; i < 4; i++)
    sig_gen_time = (sig_gen_time << 8) + buff[j++];

  signerid1 = signerid2 = 0;
  for (i = 0; i < 4; i++)
    signerid1 = (signerid1 << 8) + buff[j++];

  for (i = 0; i < 4; i++)
    signerid2 = (signerid2 << 8) + buff[j++];

  
  if (sigtype == 0x20 || sigtype == 0x28)
    p->flags |= KEYFLAG_REVOKED;

  if (s)
  {
    s->sigtype = sigtype;
    s->sid1    = signerid1;
    s->sid2    = signerid2;
  }
  
  return 0;
}

static int pgp_parse_pgp3_sig (unsigned char *buff, size_t l,
                               pgp_key_t p, pgp_sig_t *s)
{
  unsigned char sigtype;
  unsigned char pkalg;
  unsigned char hashalg;
  unsigned char skt;
  time_t sig_gen_time = -1;
  long validity = -1;
  long key_validity = -1;
  unsigned long signerid1 = 0;
  unsigned long signerid2 = 0;
  size_t ml;
  size_t j;
  int i;
  short ii;
  short have_critical_spks = 0;

  if (l < 7)
    return -1;

  j = 2;

  sigtype = buff[j++];
  pkalg = buff[j++];
  hashalg = buff[j++];

  for (ii = 0; ii < 2; ii++)
  {
    size_t skl;
    size_t nextone;

    ml = (buff[j] << 8) + buff[j + 1];
    j += 2;

    if (j + ml > l)
      break;

    nextone = j;
    while (ml)
    {
      j = nextone;
      skl = buff[j++];
      if (!--ml)
	break;

      if (skl >= 192)
      {
	skl = (skl - 192) * 256 + buff[j++] + 192;
	if (!--ml)
	  break;
      }

      if ((int) ml - (int) skl < 0)
	break;
      ml -= skl;

      nextone = j + skl;
      skt = buff[j++];