keyid.c

/* keyid.c - key ID and fingerprint handling
 * Copyright (C) 1998, 1999, 2000, 2001, 2003,
 *               2004, 2006 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG 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 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG 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, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <assert.h>

#include "gpg.h"
#include "util.h"
#include "main.h"
#include "packet.h"
#include "options.h"
#include "keydb.h"
#include "i18n.h"
#include "rmd160.h"

int
pubkey_letter( int algo )
{
    switch( algo ) {
      case PUBKEY_ALGO_RSA:	return 'R' ;
      case PUBKEY_ALGO_RSA_E:	return 'r' ;
      case PUBKEY_ALGO_RSA_S:	return 's' ;
      case PUBKEY_ALGO_ELGAMAL_E: return 'g';
      case PUBKEY_ALGO_ELGAMAL: return 'G' ;
      case PUBKEY_ALGO_DSA:	return 'D' ;
      case PUBKEY_ALGO_ECDSA:	return 'E' ;	/* ECC DSA (sign only)   */
      case PUBKEY_ALGO_ECDH:	return 'e' ;	/* ECC DH (encrypt only) */
      default: return '?';
    }
}

/* This function is useful for v4 fingerprints and v3 or v4 key
   signing. */
void
hash_public_key( gcry_md_hd_t md, PKT_public_key *pk )
{
  unsigned int n = 6;
  unsigned int nn[PUBKEY_MAX_NPKEY];
  byte *pp[PUBKEY_MAX_NPKEY];
  int i;
  unsigned int nbits;
  size_t nbytes;
  int npkey = pubkey_get_npkey (pk->pubkey_algo);

  /* Two extra bytes for the expiration date in v3 */
  if(pk->version<4)
    n+=2;

  if (npkey==0 && pk->pkey[0]
      && gcry_mpi_get_flag (pk->pkey[0], GCRYMPI_FLAG_OPAQUE))
    {
      pp[0] = gcry_mpi_get_opaque (pk->pkey[0], &nbits);
      nn[0] = (nbits+7)/8;
      n+=nn[0];
    }
  else
    for(i=0; i < npkey; i++ )
      {
	if (gcry_mpi_print (GCRYMPI_FMT_PGP, NULL, 0, &nbytes, pk->pkey[i]))
          BUG ();
	pp[i] = xmalloc (nbytes);
	if (gcry_mpi_print (GCRYMPI_FMT_PGP, pp[i], nbytes,
                            &nbytes, pk->pkey[i]))
          BUG ();
        nn[i] = nbytes;
	n += nn[i];
      }

  gcry_md_putc ( md, 0x99 );     /* ctb */
  /* What does it mean if n is greater than than 0xFFFF ? */
  gcry_md_putc ( md, n >> 8 );   /* 2 byte length header */
  gcry_md_putc ( md, n );
  gcry_md_putc ( md, pk->version );

  gcry_md_putc ( md, pk->timestamp >> 24 );
  gcry_md_putc ( md, pk->timestamp >> 16 );
  gcry_md_putc ( md, pk->timestamp >>  8 );
  gcry_md_putc ( md, pk->timestamp       );

  if(pk->version<4)
    {
      u16 days=0;
      if(pk->expiredate)
	days=(u16)((pk->expiredate - pk->timestamp) / 86400L);

      gcry_md_putc ( md, days >> 8 );
      gcry_md_putc ( md, days );
    }

  gcry_md_putc ( md, pk->pubkey_algo );

  if(npkey==0 && pk->pkey[0]
     && gcry_mpi_get_flag (pk->pkey[0], GCRYMPI_FLAG_OPAQUE))
    {
      gcry_md_write (md, pp[0], nn[0]);
    }
  else
    for(i=0; i < npkey; i++ )
      {
	gcry_md_write ( md, pp[i], nn[i] );
	xfree(pp[i]);
      }
}

static gcry_md_hd_t
do_fingerprint_md( PKT_public_key *pk )
{
  gcry_md_hd_t md;

  if (gcry_md_open (&md, DIGEST_ALGO_SHA1, 0))
    BUG ();
  hash_public_key(md,pk);
  gcry_md_final( md );

  return md;
}

static gcry_md_hd_t
do_fingerprint_md_sk( PKT_secret_key *sk )
{
    PKT_public_key pk;
    int npkey = pubkey_get_npkey( sk->pubkey_algo ); /* npkey is correct! */
    int i;

    if(npkey==0)
      return NULL;

    pk.pubkey_algo = sk->pubkey_algo;
    pk.version	   = sk->version;
    pk.timestamp = sk->timestamp;
    pk.expiredate = sk->expiredate;
    pk.pubkey_algo = sk->pubkey_algo;
    for( i=0; i < npkey; i++ )
      pk.pkey[i] = sk->skey[i];
    return do_fingerprint_md( &pk );
}


u32
v3_keyid (gcry_mpi_t a, u32 *ki)
{
  byte *buffer, *p;
  size_t nbytes;

  if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0, &nbytes, a ))
    BUG ();
  /* fixme: allocate it on the stack */
  buffer = xmalloc (nbytes);
  if (gcry_mpi_print( GCRYMPI_FMT_USG, buffer, nbytes, NULL, a ))
    BUG ();
  if (nbytes < 8) /* oops */
    ki[0] = ki[1] = 0;
  else
    {
      p = buffer + nbytes - 8;
      ki[0] = (p[0] << 24) | (p[1] <<16) | (p[2] << 8) | p[3];
      p += 4;
      ki[1] = (p[0] << 24) | (p[1] <<16) | (p[2] << 8) | p[3];
    }
  xfree (buffer);
  return ki[1];
}


size_t
keystrlen(void)
{
  switch(opt.keyid_format)
    {
    case KF_SHORT:
      return 8;

    case KF_LONG:
      return 16;

    case KF_0xSHORT:
      return 10;

    case KF_0xLONG:
      return 18;

    default:
      BUG();
    }
}

const char *
keystr(u32 *keyid)
{
  static char keyid_str[19];

  switch(opt.keyid_format)
    {
    case KF_SHORT:
      sprintf(keyid_str,"%08lX",(ulong)keyid[1]);
      break;

    case KF_LONG:
      if(keyid[0])
	sprintf(keyid_str,"%08lX%08lX",(ulong)keyid[0],(ulong)keyid[1]);
      else
	sprintf(keyid_str,"%08lX",(ulong)keyid[1]);
      break;

    case KF_0xSHORT:
      sprintf(keyid_str,"0x%08lX",(ulong)keyid[1]);
      break;

    case KF_0xLONG:
      if(keyid[0])
	sprintf(keyid_str,"0x%08lX%08lX",(ulong)keyid[0],(ulong)keyid[1]);
      else
	sprintf(keyid_str,"0x%08lX",(ulong)keyid[1]);
      break;

    default:
      BUG();
    }

  return keyid_str;
}

const char *
keystr_from_pk(PKT_public_key *pk)
{
  keyid_from_pk(pk,NULL);

  return keystr(pk->keyid);
}

const char *
keystr_from_sk(PKT_secret_key *sk)
{
  keyid_from_sk(sk,NULL);

  return keystr(sk->keyid);
}

const char *
keystr_from_desc(KEYDB_SEARCH_DESC *desc)
{
  switch(desc->mode)
    {
    case KEYDB_SEARCH_MODE_LONG_KID:
    case KEYDB_SEARCH_MODE_SHORT_KID:
      return keystr(desc->u.kid);

    case KEYDB_SEARCH_MODE_FPR20:
      {
	u32 keyid[2];

	keyid[0] = ((unsigned char)desc->u.fpr[12] << 24
                    | (unsigned char)desc->u.fpr[13] << 16
                    | (unsigned char)desc->u.fpr[14] << 8
                    | (unsigned char)desc->u.fpr[15]);
	keyid[1] = ((unsigned char)desc->u.fpr[16] << 24
                    | (unsigned char)desc->u.fpr[17] << 16
                    | (unsigned char)desc->u.fpr[18] << 8
                    | (unsigned char)desc->u.fpr[19]);

	return keystr(keyid);
      }

    case KEYDB_SEARCH_MODE_FPR16:
      return "?v3 fpr?";

    default:
      BUG();
    }
}

/****************
 * Get the keyid from the secret key and put it into keyid
 * if this is not NULL. Return the 32 low bits of the keyid.
 */
u32
keyid_from_sk( PKT_secret_key *sk, u32 *keyid )
{
  u32 lowbits;
  u32 dummy_keyid[2];

  if( !keyid )
    keyid = dummy_keyid;

  if( sk->keyid[0] || sk->keyid[1] )
    {
      keyid[0] = sk->keyid[0];
      keyid[1] = sk->keyid[1];
      lowbits = keyid[1];
    }
  else if( sk->version < 4 )
    {
      if( is_RSA(sk->pubkey_algo) )
	{
	  lowbits = (pubkey_get_npkey (sk->pubkey_algo) ?
                     v3_keyid( sk->skey[0], keyid ) : 0); /* Take n. */
	  sk->keyid[0]=keyid[0];
	  sk->keyid[1]=keyid[1];
	}
      else
	sk->keyid[0]=sk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
    }
  else
    {
      const byte *dp;
      gcry_md_hd_t md;

      md = do_fingerprint_md_sk(sk);
      if(md)
	{
	  dp = gcry_md_read (md, 0);
	  keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
	  keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
	  lowbits = keyid[1];
	  gcry_md_close (md);
	  sk->keyid[0] = keyid[0];
	  sk->keyid[1] = keyid[1];
	}
      else
	sk->keyid[0]=sk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
    }

  return lowbits;
}


/****************
 * Get the keyid from the public key and put it into keyid
 * if this is not NULL. Return the 32 low bits of the keyid.
 */
u32
keyid_from_pk( PKT_public_key *pk, u32 *keyid )
{
  u32 lowbits;
  u32 dummy_keyid[2];

  if( !keyid )
    keyid = dummy_keyid;

  if( pk->keyid[0] || pk->keyid[1] )
    {
      keyid[0] = pk->keyid[0];
      keyid[1] = pk->keyid[1];
      lowbits = keyid[1];
    }
  else if( pk->version < 4 )
    {
      if( is_RSA(pk->pubkey_algo) )
	{
	  lowbits = (pubkey_get_npkey (pk->pubkey_algo) ?
                     v3_keyid ( pk->pkey[0], keyid ) : 0); /* From n. */
	  pk->keyid[0] = keyid[0];
	  pk->keyid[1] = keyid[1];
	}
      else
	pk->keyid[0]=pk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
    }
  else
    {
      const byte *dp;
      gcry_md_hd_t md;

      md = do_fingerprint_md(pk);
      if(md)
	{
	  dp = gcry_md_read ( md, 0 );
	  keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
	  keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
	  lowbits = keyid[1];
	  gcry_md_close (md);
	  pk->keyid[0] = keyid[0];
	  pk->keyid[1] = keyid[1];
	}
      else
	pk->keyid[0]=pk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
    }

  return lowbits;
}


/****************
 * Get the keyid from the fingerprint.	This function is simple for most
 * keys, but has to do a keylookup for old stayle keys.
 */
u32
keyid_from_fingerprint( const byte *fprint, size_t fprint_len, u32 *keyid )
{
    u32 dummy_keyid[2];

    if( !keyid )
	keyid = dummy_keyid;

    if( fprint_len != 20 ) {
	/* This is special as we have to lookup the key first */
	PKT_public_key pk;
	int rc = 0;

	memset( &pk, 0, sizeof pk );
//	rc = get_pubkey_byfprint( &pk, fprint, fprint_len ); // FIXME
	if( rc ) {
	    log_error("Oops: keyid_from_fingerprint: no pubkey\n");
	    keyid[0] = 0;
	    keyid[1] = 0;
	}
	else
	    keyid_from_pk( &pk, keyid );
    }
    else {
	const byte *dp = fprint;
	keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
	keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
    }

    return keyid[1];
}


u32
keyid_from_sig( PKT_signature *sig, u32 *keyid )
{
    if( keyid ) {
	keyid[0] = sig->keyid[0];
	keyid[1] = sig->keyid[1];
    }
    return sig->keyid[1];
}

byte *
namehash_from_uid(PKT_user_id *uid)
{
  if (!uid->namehash)
    {
      uid->namehash = xmalloc (20);

      if(uid->attrib_data)
	rmd160_hash_buffer (uid->namehash, uid->attrib_data, uid->attrib_len);
      else
	rmd160_hash_buffer (uid->namehash, uid->name, uid->len);
    }

  return uid->namehash;
}

/****************
 * return the number of bits used in the pk
 */
unsigned
nbits_from_pk( PKT_public_key *pk )
{
    return pubkey_nbits( pk->pubkey_algo, pk->pkey );
}

/****************
 * return the number of bits used in the sk
 */
unsigned
nbits_from_sk( PKT_secret_key *sk )
{
    return pubkey_nbits( sk->pubkey_algo, sk->skey );
}

static const char *
mk_datestr (char *buffer, time_t atime)
{
    struct tm *tp;

    if ( atime < 0 ) /* 32 bit time_t and after 2038-01-19 */
        strcpy (buffer, "????" "-??" "-??"); /* mark this as invalid */
    else {
        tp = gmtime (&atime);
        sprintf (buffer,"%04d-%02d-%02d",
                 1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday );
    }
    return buffer;
}

/****************
 * return a string with the creation date of the pk
 * Note: this is alloced in a static buffer.
 *    Format is: yyyy-mm-dd
 */
const char *
datestr_from_pk( PKT_public_key *pk )
{
    static char buffer[11+5];
    time_t atime = pk->timestamp;

    return mk_datestr (buffer, atime);
}

const char *
datestr_from_sk( PKT_secret_key *sk )
{
    static char buffer[11+5];
    time_t atime = sk->timestamp;

    return mk_datestr (buffer, atime);
}

const char *
datestr_from_sig( PKT_signature *sig )
{
    static char buffer[11+5];
    time_t atime = sig->timestamp;

    return mk_datestr (buffer, atime);
}

const char *
expirestr_from_pk( PKT_public_key *pk )
{
    static char buffer[11+5];
    time_t atime;

    if( !pk->expiredate )
	return _("never     ");
    atime = pk->expiredate;
    return mk_datestr (buffer, atime);
}

const char *
expirestr_from_sk( PKT_secret_key *sk )
{
    static char buffer[11+5];
    time_t atime;

    if( !sk->expiredate )
	return _("never     ");
    atime = sk->expiredate;
    return mk_datestr (buffer, atime);
}

const char *
expirestr_from_sig( PKT_signature *sig )
{
    static char buffer[11+5];
    time_t atime;

    if(!sig->expiredate)
      return _("never     ");
    atime=sig->expiredate;
    return mk_datestr (buffer, atime);
}

const char *
revokestr_from_pk( PKT_public_key *pk )
{
    static char buffer[11+5];
    time_t atime;

    if(!pk->revoked.date)
      return _("never     ");
    atime=pk->revoked.date;
    return mk_datestr (buffer, atime);
}


const char *
usagestr_from_pk( PKT_public_key *pk )
{
  static char buffer[10];
  int i = 0;
  unsigned int use = pk->pubkey_usage;

  if ( use & PUBKEY_USAGE_SIG )
    buffer[i++] = 'S';

  if ( use & PUBKEY_USAGE_CERT )
    buffer[i++] = 'C';

  if ( use & PUBKEY_USAGE_ENC )
    buffer[i++] = 'E';

  if ( (use & PUBKEY_USAGE_AUTH) )
    buffer[i++] = 'A';

  while (i < 4)
    buffer[i++] = ' ';

  buffer[i] = 0;
  return buffer;
}


const char *
colon_strtime (u32 t)
{
  static char buf[20];

  if (!t)
    return "";
  snprintf (buf, sizeof buf, "%lu", (ulong)t);
  return buf;
}

const char *
colon_datestr_from_pk (PKT_public_key *pk)
{
  static char buf[20];

  snprintf (buf, sizeof buf, "%lu", (ulong)pk->timestamp);
  return buf;
}

const char *
colon_datestr_from_sk (PKT_secret_key *sk)
{
  static char buf[20];

  snprintf (buf, sizeof buf, "%lu", (ulong)sk->timestamp);
  return buf;
}

const char *
colon_datestr_from_sig (PKT_signature *sig)
{
  static char buf[20];

  snprintf (buf, sizeof buf, "%lu", (ulong)sig->timestamp);
  return buf;
}

const char *
colon_expirestr_from_sig (PKT_signature *sig)
{
  static char buf[20];

  if (!sig->expiredate)
    return "";

  snprintf (buf, sizeof buf,"%lu", (ulong)sig->expiredate);
  return buf;
}


/**************** .
 * Return a byte array with the fingerprint for the given PK/SK
 * The length of the array is returned in ret_len. Caller must free
 * the array or provide an array of length MAX_FINGERPRINT_LEN.
 */

byte *
fingerprint_from_pk( PKT_public_key *pk, byte *array, size_t *ret_len )
{
  byte *buf;
  const byte *dp;
  size_t len, nbytes;
  int i;

  if ( pk->version < 4 )
    {
      if ( is_RSA(pk->pubkey_algo) )
        {
          /* RSA in version 3 packets is special. */
          gcry_md_hd_t md;

          if (gcry_md_open (&md, DIGEST_ALGO_MD5, 0))
            BUG ();
          if ( pubkey_get_npkey (pk->pubkey_algo) > 1 )
            {
              for (i=0; i < 2; i++)
                {
                  if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0,
                                      &nbytes, pk->pkey[i]))
                    BUG ();
                  /* fixme: Better allocate BUF on the stack */
                  buf = xmalloc (nbytes);
                  if (gcry_mpi_print (GCRYMPI_FMT_USG, buf, nbytes,
                                      NULL, pk->pkey[i]))
                    BUG ();
                  gcry_md_write (md, buf, nbytes);
                  xfree (buf);
                }
            }
          gcry_md_final (md);
          if (!array)
            array = xmalloc (16);
          len = 16;
          memcpy (array, gcry_md_read (md, DIGEST_ALGO_MD5), 16);
          gcry_md_close(md);
        }
      else
        {
          if (!array)
            array = xmalloc(16);
          len = 16;
          memset (array,0,16);
        }
    }
  else
    {
      gcry_md_hd_t md;

      md = do_fingerprint_md(pk);
      dp = gcry_md_read( md, 0 );
      len = gcry_md_get_algo_dlen (gcry_md_get_algo (md));
      assert( len <= MAX_FINGERPRINT_LEN );
      if (!array)
        array = xmalloc ( len );
      memcpy (array, dp, len );
      pk->keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
      pk->keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
      gcry_md_close( md);
    }

  *ret_len = len;
  return array;
}

byte *
fingerprint_from_sk( PKT_secret_key *sk, byte *array, size_t *ret_len )
{
  byte *buf;
  const char *dp;
  size_t len, nbytes;
  int i;

  if (sk->version < 4)
    {
      if ( is_RSA(sk->pubkey_algo) )
        {
          /* RSA in version 3 packets is special. */
          gcry_md_hd_t md;

          if (gcry_md_open (&md, DIGEST_ALGO_MD5, 0))
            BUG ();
          if (pubkey_get_npkey( sk->pubkey_algo ) > 1)
            {
              for (i=0; i < 2; i++)
                {
                  if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0,
                                      &nbytes, sk->skey[i]))
                    BUG ();
                  /* fixme: Better allocate BUF on the stack */
                  buf = xmalloc (nbytes);
                  if (gcry_mpi_print (GCRYMPI_FMT_USG, buf, nbytes,
                                      NULL, sk->skey[i]))
                    BUG ();
                  gcry_md_write (md, buf, nbytes);
                  xfree (buf);
                }
	    }
          gcry_md_final(md);
          if (!array)
            array = xmalloc (16);
          len = 16;
          memcpy (array, gcry_md_read (md, DIGEST_ALGO_MD5), 16);
          gcry_md_close (md);
        }
      else
        {
          if (!array)
            array = xmalloc (16);
          len=16;
          memset (array,0,16);
        }
    }
  else
    {
      gcry_md_hd_t md;

      md = do_fingerprint_md_sk(sk);
      if (md)
        {
          dp = gcry_md_read ( md, 0 );
          len = gcry_md_get_algo_dlen ( gcry_md_get_algo (md) );
          assert ( len <= MAX_FINGERPRINT_LEN );
          if (!array)
            array = xmalloc( len );
          memcpy (array, dp, len);
          gcry_md_close (md);
        }
      else
        {
          len = MAX_FINGERPRINT_LEN;
          if (!array)
            array = xmalloc (len);
          memset (array, 0, len);
        }
    }

  *ret_len = len;
  return array;
}


/* Create a serialno/fpr string from the serial number and the secret
   key.  Caller must free the returned string.  There is no error
   return.  */
char *
serialno_and_fpr_from_sk (const unsigned char *sn, size_t snlen,
                          PKT_secret_key *sk)
{
  unsigned char fpr[MAX_FINGERPRINT_LEN];
  size_t fprlen;
  char *buffer, *p;
  int i;

  fingerprint_from_sk (sk, fpr, &fprlen);
  buffer = p = xmalloc (snlen*2 + 1 + fprlen*2 + 1);
  for (i=0; i < snlen; i++, p+=2)
    sprintf (p, "%02X", sn[i]);
  *p++ = '/';
  for (i=0; i < fprlen; i++, p+=2)
    sprintf (p, "%02X", fpr[i]);
  *p = 0;
  return buffer;
}