trunk/Gnupg/parse-packet.c

/* parse-packet.c  - read packets
 * Copyright (C) 1998, 1999, 2000, 2001, 2002 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <assert.h>
#include <process.h>
#include <sys/types.h>

#include "openpgp.h"
#include "packet.h"
#include "md.h"

static int mpi_print_mode = 0;
static int list_mode = 0;

static int  parse( gpg_iobuf_t inp, PACKET *pkt, int onlykeypkts,
                  _off_t *retpos, int *skip, gpg_iobuf_t out, int do_skip );
static int  copy_packet( gpg_iobuf_t inp, gpg_iobuf_t out, int pkttype,
                                               unsigned long pktlen );
static void skip_packet( gpg_iobuf_t inp, int pkttype, unsigned long pktlen );
static void skip_rest( gpg_iobuf_t inp, unsigned long pktlen );
static void *read_rest( gpg_iobuf_t inp, size_t pktlen );
static int  parse_symkeyenc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                             PACKET *packet );
static int  parse_pubkeyenc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                             PACKET *packet );
static int  parse_signature( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                         PKT_signature *sig );
static int  parse_onepass_sig( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                        PKT_onepass_sig *ops );
static int  parse_key( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                      byte *hdr, int hdrlen, PACKET *packet );
static int  parse_user_id( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                           PACKET *packet );
static int  parse_attribute( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                           PACKET *packet );
static int  parse_comment( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                           PACKET *packet );
static void parse_trust( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                                           PACKET *packet );
static int  parse_plaintext( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                               PACKET *packet, int new_ctb);
static int  parse_compressed( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                               PACKET *packet, int new_ctb );
static int  parse_encrypted( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                               PACKET *packet, int new_ctb);
static int  parse_mdc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                               PACKET *packet, int new_ctb);
static int  parse_gpg_control( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                               PACKET *packet );

static unsigned short
read_16(gpg_iobuf_t inp)
{
    unsigned short a;
    a = gpg_iobuf_get_noeof(inp) << 8;
    a |= gpg_iobuf_get_noeof(inp);
    return a;
}

static unsigned long
read_32(gpg_iobuf_t inp)
{
    unsigned long a;
    a =  gpg_iobuf_get_noeof(inp) << 24;
    a |= gpg_iobuf_get_noeof(inp) << 16;
    a |= gpg_iobuf_get_noeof(inp) << 8;
    a |= gpg_iobuf_get_noeof(inp);
    return a;
}

static unsigned long
buffer_to_u32( const unsigned char *buffer )
{
    unsigned long a;
    a =  *buffer << 24;
    a |= buffer[1] << 16;
    a |= buffer[2] << 8;
    a |= buffer[3];
    return a;
}

int
set_packet_list_mode( int mode )
{
    int old = list_mode;
    list_mode = mode;
    mpi_print_mode = 0;
    return old;
}

static void
unknown_pubkey_warning( int algo )
{
    static byte unknown_pubkey_algos[256];
    
    algo &= 0xff;
    if( !unknown_pubkey_algos[algo] ) { 
        unknown_pubkey_algos[algo] = 1;
    }
}

static const char *
strtimestamp( unsigned long stamp )
{
    static char buffer[11+5];
    struct tm *tp;
    time_t atime = stamp;
    
    if (atime < 0) {
        strcpy (buffer, "????" "-??" "-??");
    }
    else {
        tp = gmtime( &atime );
        sprintf(buffer,"%04d-%02d-%02d",
                1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday );
    }
    return buffer;
}

static const char *
strtimevalue( unsigned long value )
{
    static char buffer[30];
    unsigned int years, days, hours, minutes;
    
    value /= 60;
    minutes = value % 60;
    value /= 60;
    hours = value % 24;
    value /= 24;
    days = value % 365;
    value /= 365;
    years = value;
    
    sprintf(buffer,"%uy%ud%uh%um", years, days, hours, minutes );
    if( years )
        return buffer;
    if( days )
        return strchr( buffer, 'y' ) + 1;
    return strchr( buffer, 'd' ) + 1;
}


static gpg_mpi_t
mpi_read( gpg_iobuf_t inp, size_t *ret_n, int flags )
{
    gpg_mpi_t a;
    int i = 0, j = 0;
    u32 t;
    size_t n;
    
    a = calloc( 1, sizeof *a );
    a->nbits = read_16( inp );
    n = (a->nbits + 7) / 8;        
    a->alloced = n;
    a->d = calloc( n, 4 );
    i = 4 - n % 4;
    i %= 4;
    j = (n+4-1) / 4;    
    for( ; j > 0; j-- ) {
        t = 0;
        for( ; i < 4; i++ ) {
            t <<= 8;
            t |= gpg_iobuf_get( inp ) & 0xff;
        }
        i = 0;
        a->d[j-1] = t;
    }
    if( *ret_n )
        *ret_n = n + 2;
    
    return a;
}

void
mpi_print( FILE *fp, gpg_mpi_t a, int mode )
{
    int i;
    for( i = 0; i < a->alloced / 4; i++ )
        printf( "%08lx", a->d[i] );
}

static void
mpi_set_protect_flag( gpg_mpi_t a )
{
    a->flags = 1;
}

static gpg_mpi_t
mpi_set_opaque( gpg_mpi_t a, void *p, int len )
{
    if( !a ) {
        a = calloc( 1, sizeof *a );
    }
    
    if( a->flags & 4 )
        safe_free( a->d );
    else {
        safe_free( a->d );
    }
    
    a->d = p;
    a->alloced = 0;
    a->nlimbs = 0;
    a->nbits = len;
    a->flags = 4;
    return a;
}

void
free_symkey_enc( PKT_symkey_enc *enc )
{
    safe_free(enc);
}

void
free_pubkey_enc( PKT_pubkey_enc *enc )
{
    int n, i;
    n = pubkey_get_nenc( enc->pubkey_algo );
    if( !n )
        safe_free(enc->data[0]);
    for(i=0; i < n; i++ )
        safe_free( enc->data[i] );
    safe_free(enc);
}

void
free_seckey_enc( PKT_signature *sig )
{
    int n, i;
    
    n = pubkey_get_nsig( sig->pubkey_algo );
    if( !n )
        safe_free(sig->data[0]);
    for(i=0; i < n; i++ )
        safe_free( sig->data[i] );
    
    safe_free(sig->revkey);
    safe_free(sig->hashed);
    safe_free(sig->unhashed);
    safe_free(sig);
}


void
release_public_key_parts( PKT_public_key *pk )
{
    int n, i;
    n = pubkey_get_npkey( pk->pubkey_algo );
    if( !n )
        safe_free(pk->pkey[0]);
    for(i=0; i < n; i++ ) {
        safe_free( pk->pkey[i] );
        pk->pkey[i] = NULL;
    }
    if (pk->prefs) {
        safe_free (pk->prefs);
        pk->prefs = NULL;
    }
    if( pk->namehash ) {
        safe_free(pk->namehash);
        pk->namehash = NULL;
    }
    if (pk->user_id) {
        free_user_id (pk->user_id);
        pk->user_id = NULL;
    }
    if (pk->revkey) {
        safe_free(pk->revkey);
        pk->revkey=NULL;
        pk->numrevkeys=0;
    }
}


void
free_public_key( PKT_public_key *pk )
{
    release_public_key_parts( pk );
    safe_free(pk);
}


int
pubkey_get_nenc( int algo )
{
    switch( algo ) {
    case 1:
    case 2:
    case 3:  return 1;          
    case 16:
    case 20: return 2;
    }
    return 0;
}

int
pubkey_get_nsig( algo )
{
    switch( algo ) {
    case  1:
    case  2:
    case  3: return 1;
    case 17:
    case 16:
    case 20: return 2;
    }
    return 0;
}

int
pubkey_get_npkey( int algo )
{       
    if( is_ELGAMAL( algo ) )   return 3;        
    else if ( algo == 17 )     return 4;
    else if ( is_RSA( algo ) ) return 2;
    return 0;
} /* cdk_pk_get_npkey */

int
pubkey_get_nskey( int algo )
{
    if ( is_ELGAMAL( algo ) ) return 4;
    else if ( algo == 17 )    return 5; 
    else if ( is_RSA( algo ) )return 6;
    return 0;
} /* cdk_pk_get_nskey */


static subpktarea_t *
cp_subpktarea (subpktarea_t *s )
{
    subpktarea_t *d;
    
    if( !s )
        return NULL;
    d = malloc (sizeof (*d) + s->size - 1 );
    d->size = s->size;
    d->len = s->len;
    memcpy (d->data, s->data, s->len);
    return d;
}

/*
 * Return a copy of the preferences 
 */
prefitem_t *
copy_prefs (const prefitem_t *prefs)
{
    size_t n;
    prefitem_t *new;
    
    if (!prefs)
        return NULL;
    
    for (n=0; prefs[n].type; n++)
        ;
    new = malloc ( sizeof (*new) * (n+1));
    for (n=0; prefs[n].type; n++) {
        new[n].type = prefs[n].type;
        new[n].value = prefs[n].value;
    }
    new[n].type = PREFTYPE_NONE;
    new[n].value = 0;
    
    return new;
}

/****************
 * Replace all common parts of a sk by the one from the public key.
 * This is a hack and a better solution will be to just store the real secret
 * parts somewhere and don't duplicate all the other stuff.
 */
void
copy_public_parts_to_secret_key( PKT_public_key *pk, PKT_secret_key *sk )
{
    sk->expiredate  = pk->expiredate;     
    sk->pubkey_algo = pk->pubkey_algo;    
    sk->pubkey_usage= pk->pubkey_usage;
    sk->req_usage   = pk->req_usage;
    sk->req_algo    = pk->req_algo;
    sk->has_expired = pk->has_expired;    
    sk->is_revoked  = pk->is_revoked;     
    sk->is_valid    = pk->is_valid;    
    sk->main_keyid[0]= pk->main_keyid[0];
    sk->main_keyid[1]= pk->main_keyid[1];
    sk->keyid[0]    = pk->keyid[0];
    sk->keyid[1]    = pk->keyid[1];
}

void
release_secret_key_parts( PKT_secret_key *sk )
{
    int n, i;
    
    n = pubkey_get_nskey( sk->pubkey_algo );
    if( !n )
        safe_free(sk->skey[0]);
    for(i=0; i < n; i++ ) {
        safe_free( sk->skey[i] );
        sk->skey[i] = NULL;
    }
}

void
free_secret_key( PKT_secret_key *sk )
{
    release_secret_key_parts( sk );
    safe_free(sk);
}

void
free_comment( PKT_comment *rem )
{
    safe_free(rem);
}

void
free_attributes(PKT_user_id *uid)
{
    safe_free(uid->attribs);
    safe_free(uid->attrib_data);
    
    uid->attribs=NULL;
    uid->attrib_data=NULL;
    uid->attrib_len=0;
}

void
free_user_id (PKT_user_id *uid)
{
    assert (uid->ref > 0);
    if (--uid->ref)
        return;
    
    free_attributes(uid);
    
    if (uid->prefs)
        safe_free (uid->prefs);
    safe_free (uid);
}

void
free_compressed( PKT_compressed *zd )
{
    if( zd->buf ) { /* have to skip some bytes */
        /* don't have any information about the length, so
         * we assume this is the last packet */
        while( gpg_iobuf_read( zd->buf, NULL, 1<<30 ) != -1 )
            ;
    }
    safe_free(zd);
}

void
free_encrypted( PKT_encrypted *ed )
{
    if( ed->buf ) { /* have to skip some bytes */
        if( gpg_iobuf_in_block_mode(ed->buf) ) {
            while( gpg_iobuf_read( ed->buf, NULL, 1<<30 ) != -1 )
                ;
        }
        else {
            while( ed->len ) { /* skip the packet */
                int n = gpg_iobuf_read( ed->buf, NULL, ed->len );
                if( n == -1 )
                    ed->len = 0;
                else
                    ed->len -= n;
            }
        }
    }
    safe_free(ed);
}


void
free_plaintext( PKT_plaintext *pt )
{
    if( pt->buf ) { /* have to skip some bytes */
        if( gpg_iobuf_in_block_mode(pt->buf) ) {
            while( gpg_iobuf_read( pt->buf, NULL, 1<<30 ) != -1 )
                ;
        }
        else {
            while( pt->len ) { /* skip the packet */
                int n = gpg_iobuf_read( pt->buf, NULL, pt->len );
                if( n == -1 )
                    pt->len = 0;
                else
                    pt->len -= n;
            }
        }
    }
    safe_free(pt);
}

/****************
 * Free the packet in pkt.
 */
void
gpg_free_packet( PACKET *pkt )
{
    if( !pkt || !pkt->pkt.generic )
        return;
    
    switch( pkt->pkttype ) {
    case PKT_SIGNATURE:
        free_seckey_enc( pkt->pkt.signature );
        break;
    case PKT_PUBKEY_ENC:
        free_pubkey_enc( pkt->pkt.pubkey_enc );
        break;
    case PKT_SYMKEY_ENC:
        free_symkey_enc( pkt->pkt.symkey_enc );
        break;
    case PKT_PUBLIC_KEY:
    case PKT_PUBLIC_SUBKEY:
        free_public_key( pkt->pkt.public_key );
        break;
    case PKT_SECRET_KEY:
    case PKT_SECRET_SUBKEY:
        free_secret_key( pkt->pkt.secret_key );
        break;
    case PKT_COMMENT:
        free_comment( pkt->pkt.comment );
        break;
    case PKT_USER_ID:
        free_user_id( pkt->pkt.user_id );
        break;
    case PKT_COMPRESSED:
        free_compressed( pkt->pkt.compressed);
        break;
    case PKT_ENCRYPTED:
    case PKT_ENCRYPTED_MDC:
        free_encrypted( pkt->pkt.encrypted );
        break;
    case PKT_PLAINTEXT:
        free_plaintext( pkt->pkt.plaintext );
        break;
    default:
        safe_free( pkt->pkt.generic );
        break;
    }
    pkt->pkt.generic = NULL;
}


/****************
 * Parse a Packet and return it in packet
 * Returns: 0 := valid packet in pkt
 *         -1 := no more packets
 *         >0 := error
 * Note: The function may return an error and a partly valid packet;
 * caller must free this packet.
 */
int
gpg_parse_packet( gpg_iobuf_t inp, PACKET *pkt )
{
    int skip, rc;
    
    do {
        rc = parse( inp, pkt, 0, NULL, &skip, NULL, 0 );
    } while( skip );
    return rc;
}

/****************
 * Like parse packet, but only return secret or public (sub)key packets.
 */
int
search_packet( gpg_iobuf_t inp, PACKET *pkt, _off_t *retpos, int with_uid )
{
    int skip, rc;
    
    do {
        rc = parse( inp, pkt, with_uid?2:1, retpos, &skip, NULL, 0 );
    } while( skip );
    return rc;
}

/****************
 * Copy all packets from INP to OUT, thereby removing unused spaces.
 */
int
copy_all_packets( gpg_iobuf_t inp, gpg_iobuf_t out )
{
    PACKET pkt;
    int skip, rc=0;
    do {
        gpg_init_packet(&pkt);
    } while( !(rc = parse( inp, &pkt, 0, NULL, &skip, out, 0 )));
    return rc;
}

/****************
 * Copy some packets from INP to OUT, thereby removing unused spaces.
 * Stop at offset STOPoff (i.e. don't copy packets at this or later offsets)
 */
int
copy_some_packets( gpg_iobuf_t inp, gpg_iobuf_t out, _off_t stopoff )
{
    PACKET pkt;
    int skip, rc=0;
    do {
        if( gpg_iobuf_tell(inp) >= stopoff )
            return 0;
        gpg_init_packet(&pkt);
    } while( !(rc = parse( inp, &pkt, 0, NULL, &skip, out, 0 )) );
    return rc;
}

/****************
 * Skip over N packets
 */
int
skip_some_packets( gpg_iobuf_t inp, unsigned n )
{
    int skip, rc=0;
    PACKET pkt;
    
    for( ;n && !rc; n--) {
        gpg_init_packet(&pkt);
        rc = parse( inp, &pkt, 0, NULL, &skip, NULL, 1 );
    }
    return rc;
}

/****************
 * Parse packet. Set the variable skip points to 1 if the packet
 * should be skipped; this is the case if either ONLYKEYPKTS is set
 * and the parsed packet isn't one or the
 * packet-type is 0, indicating deleted stuff.
 * if OUT is not NULL, a special copymode is used.
 */
static int
parse( gpg_iobuf_t inp, PACKET *pkt, int onlykeypkts, _off_t *retpos,
       int *skip, gpg_iobuf_t out, int do_skip
     )
{
    int rc=0, c, ctb, pkttype, lenbytes;
    unsigned long pktlen;
    byte hdr[8];
    int hdrlen;
    int new_ctb = 0;
    int with_uid = (onlykeypkts == 2);
    
    *skip = 0;
    /*assert( !pkt->pkt.generic );*/
    if( retpos )
        *retpos = gpg_iobuf_tell(inp);
    
    if( (ctb = gpg_iobuf_get(inp)) == -1 ) {
        rc = -1;
        goto leave;
    }
    hdrlen=0;
    hdr[hdrlen++] = ctb;
    if( !(ctb & 0x80) ) {
        printf("%s: invalid packet (ctb=%02x)\n", gpg_iobuf_where(inp), ctb );
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    pktlen = 0;
    new_ctb = !!(ctb & 0x40);
    if( new_ctb ) {
        pkttype = ctb & 0x3f;
        if( (c = gpg_iobuf_get(inp)) == -1 ) {
            printf("%s: 1st length byte missing\n", gpg_iobuf_where(inp) );
            rc = G10ERR_INVALID_PACKET;
            goto leave;
        }
        if (pkttype == PKT_COMPRESSED) {
            gpg_iobuf_set_partial_block_mode(inp, c & 0xff);
            pktlen = 0;/* to indicate partial length */
        }
        else {
            hdr[hdrlen++] = c;
            if( c < 192 )
                pktlen = c;
            else if( c < 224 ) {
                pktlen = (c - 192) * 256;
                if( (c = gpg_iobuf_get(inp)) == -1 ) {
                    printf("%s: 2nd length byte missing\n",
                           gpg_iobuf_where(inp) );
                    rc = G10ERR_INVALID_PACKET;
                    goto leave;
                }
                hdr[hdrlen++] = c;
                pktlen += c + 192;
            }
            else if( c == 255 ) {
                pktlen  = (hdr[hdrlen++] = gpg_iobuf_get_noeof(inp)) << 24;
                pktlen |= (hdr[hdrlen++] = gpg_iobuf_get_noeof(inp)) << 16;
                pktlen |= (hdr[hdrlen++] = gpg_iobuf_get_noeof(inp)) << 8;
                if( (c = gpg_iobuf_get(inp)) == -1 ) {
                    printf("%s: 4 byte length invalid\n",
                           gpg_iobuf_where(inp) );
                    rc = G10ERR_INVALID_PACKET;
                    goto leave;
                }
                pktlen |= (hdr[hdrlen++] = c );
            }
            else { /* partial body length */
                gpg_iobuf_set_partial_block_mode(inp, c & 0xff);
                pktlen = 0;/* to indicate partial length */
            }
        }
    }
    else {
        pkttype = (ctb>>2)&0xf;
        lenbytes = ((ctb&3)==3)? 0 : (1<<(ctb & 3));
        if( !lenbytes ) {
            pktlen = 0; /* don't know the value */
            if( pkttype != PKT_COMPRESSED )
                gpg_iobuf_set_block_mode(inp, 1);
        }
        else {
            for( ; lenbytes; lenbytes-- ) {
                pktlen <<= 8;
                pktlen |= hdr[hdrlen++] = gpg_iobuf_get_noeof(inp);
            }
        }
    }
    
    if (pktlen == 0xffffffff) {
        /* with a some probability this is caused by a problem in the
         * the uncompressing layer - in some error cases it just loops
         * and spits out 0xff bytes. */
        printf ("%s: garbled packet detected\n", gpg_iobuf_where(inp) );
        exit (2);
    }
    
    if( out && pkttype  ) {
        if( gpg_iobuf_write( out, hdr, hdrlen ) == -1 )
            rc = G10ERR_WRITE_FILE;
        else
            rc = copy_packet(inp, out, pkttype, pktlen );
        goto leave;
    }
    
    if (with_uid && pkttype == PKT_USER_ID)
        ;
    else if( do_skip 
             || !pkttype
             || (onlykeypkts && pkttype != PKT_PUBLIC_SUBKEY
                 && pkttype != PKT_PUBLIC_KEY
                 && pkttype != PKT_SECRET_SUBKEY
                 && pkttype != PKT_SECRET_KEY  ) ) {
        skip_rest(inp, pktlen);
        *skip = 1;
        rc = 0;
        goto leave;
    }
    
    pkt->pkttype = pkttype;
    rc = G10ERR_UNKNOWN_PACKET; /* default error */
    switch( pkttype ) {
    case PKT_PUBLIC_KEY:
    case PKT_PUBLIC_SUBKEY:
        pkt->pkt.public_key = calloc(1, sizeof *pkt->pkt.public_key );
        rc = parse_key(inp, pkttype, pktlen, hdr, hdrlen, pkt );
        break;
    case PKT_SECRET_KEY:
    case PKT_SECRET_SUBKEY:
        pkt->pkt.secret_key = calloc(1,sizeof *pkt->pkt.secret_key );
        rc = parse_key(inp, pkttype, pktlen, hdr, hdrlen, pkt );
        break;
    case PKT_SYMKEY_ENC:
        rc = parse_symkeyenc( inp, pkttype, pktlen, pkt );
        break;
    case PKT_PUBKEY_ENC:
        rc = parse_pubkeyenc(inp, pkttype, pktlen, pkt );
        break;
    case PKT_SIGNATURE:
        pkt->pkt.signature = calloc(1,sizeof *pkt->pkt.signature );
        rc = parse_signature(inp, pkttype, pktlen, pkt->pkt.signature );
        break;
    case PKT_ONEPASS_SIG:
        pkt->pkt.onepass_sig = calloc(1,sizeof *pkt->pkt.onepass_sig );
        rc = parse_onepass_sig(inp, pkttype, pktlen, pkt->pkt.onepass_sig );
        break;
    case PKT_USER_ID:
        rc = parse_user_id(inp, pkttype, pktlen, pkt );
        break;
    case PKT_ATTRIBUTE:
        pkt->pkttype = pkttype = PKT_USER_ID;  /* we store it in the userID */
        rc = parse_attribute(inp, pkttype, pktlen, pkt);
        break;
    case PKT_OLD_COMMENT:
    case PKT_COMMENT:
        rc = parse_comment(inp, pkttype, pktlen, pkt);
        break;
    case PKT_RING_TRUST:
        parse_trust(inp, pkttype, pktlen, pkt);
        rc = 0;
        break;
    case PKT_PLAINTEXT:
        rc = parse_plaintext(inp, pkttype, pktlen, pkt, new_ctb );
        break;
    case PKT_COMPRESSED:
        rc = parse_compressed(inp, pkttype, pktlen, pkt, new_ctb );
        break;
    case PKT_ENCRYPTED:
    case PKT_ENCRYPTED_MDC:
        rc = parse_encrypted(inp, pkttype, pktlen, pkt, new_ctb );
        break;
    case PKT_MDC:
        rc = parse_mdc(inp, pkttype, pktlen, pkt, new_ctb );
        break;
    case PKT_GPG_CONTROL:
        rc = parse_gpg_control(inp, pkttype, pktlen, pkt );
        break;
    default:
        skip_packet(inp, pkttype, pktlen);
        break;
    }
    
leave:
    if( !rc && gpg_iobuf_error(inp) )
        rc = G10ERR_INV_KEYRING;
    return rc;
}

static void
dump_hex_line( int c, int *i )
{
    if( *i && !(*i%8) ) {
        if( *i && !(*i%24) )
            printf("\n%4d:", *i );
        else
            putchar(' ');
    }
    if( c == -1 )
        printf(" EOF" );
    else
        printf(" %02x", c );
    ++*i;
}


static int
copy_packet( gpg_iobuf_t inp, gpg_iobuf_t out, int pkttype, unsigned long pktlen )
{
    int n;
    char buf[100];
    
    if( gpg_iobuf_in_block_mode(inp) ) {
        while( (n = gpg_iobuf_read( inp, buf, 100 )) != -1 )
            if( gpg_iobuf_write(out, buf, n ) )
                return G10ERR_WRITE_FILE; /* write error */
    }
    else if( !pktlen && pkttype == PKT_COMPRESSED ) {
        printf("copy_packet: compressed!\n");
        /* compressed packet, copy till EOF */
        while( (n = gpg_iobuf_read( inp, buf, 100 )) != -1 )
            if( gpg_iobuf_write(out, buf, n ) )
                return G10ERR_WRITE_FILE; /* write error */
    }
    else {
        for( ; pktlen; pktlen -= n ) {
            n = pktlen > 100 ? 100 : pktlen;
            n = gpg_iobuf_read( inp, buf, n );
            if( n == -1 )
                return G10ERR_READ_FILE;
            if( gpg_iobuf_write(out, buf, n ) )
                return G10ERR_WRITE_FILE; /* write error */
        }
    }
    return 0;
}


static void
skip_packet( gpg_iobuf_t inp, int pkttype, unsigned long pktlen )
{
    if( list_mode ) {
        if( pkttype == PKT_MARKER )
            fputs(":marker packet:\n", stdout );
        else
            printf(":unknown packet: type %2d, length %lu\n", pkttype, pktlen);
        if( pkttype ) {
            int c, i=0 ;
            if( pkttype != PKT_MARKER )
                fputs("dump:", stdout );
            if( gpg_iobuf_in_block_mode(inp) ) {
                while( (c=gpg_iobuf_get(inp)) != -1 )
                    dump_hex_line(c, &i);
            }
            else {
                for( ; pktlen; pktlen-- )
                    dump_hex_line(gpg_iobuf_get(inp), &i);
            }
            putchar('\n');
            return;
        }
    }
    skip_rest(inp,pktlen);
}

static void
skip_rest( gpg_iobuf_t inp, unsigned long pktlen )
{
    if( gpg_iobuf_in_block_mode(inp) ) {
        while( gpg_iobuf_get(inp) != -1 )
            ;
    }
    else {
        for( ; pktlen; pktlen-- )
            if( gpg_iobuf_get(inp) == -1 )
                break;
    }
}


static void *
read_rest( gpg_iobuf_t inp, size_t pktlen )
{
    byte *p;
    int i;
    
    if( gpg_iobuf_in_block_mode(inp) ) {
        printf("read_rest: can't store stream data\n");
        p = NULL;
    }
    else {
        p = malloc( pktlen );
        for(i=0; pktlen; pktlen--, i++ )
            p[i] = gpg_iobuf_get(inp);
    }
    return p;
}


static int
parse_symkeyenc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *packet )
{
    PKT_symkey_enc *k;
    int rc = 0;
    int i, version, s2kmode, cipher_algo, hash_algo, seskeylen, minlen;
    
    if( pktlen < 4 ) {
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    version = gpg_iobuf_get_noeof(inp); pktlen--;
    if( version != 4 ) {
        printf("packet(%d) with unknown version %d\n", pkttype, version);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    if( pktlen > 200 ) { /* (we encode the seskeylen in a byte) */
        printf("packet(%d) too large\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    cipher_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    s2kmode = gpg_iobuf_get_noeof(inp); pktlen--;
    hash_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    switch( s2kmode ) {
    case 0:  /* simple s2k */
        minlen = 0;
        break;
    case 1:  /* salted s2k */
        minlen = 8;
        break;
    case 3:  /* iterated+salted s2k */
        minlen = 9;
        break;
    default:
        printf("unknown S2K %d\n", s2kmode );
        goto leave;
    }
    if( minlen > pktlen ) {
        printf("packet with S2K %d too short\n", s2kmode );
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    seskeylen = pktlen - minlen;
    k = packet->pkt.symkey_enc = calloc(1, sizeof *packet->pkt.symkey_enc
                                                + seskeylen - 1 );
    k->version = version;
    k->cipher_algo = cipher_algo;
    k->s2k.mode = s2kmode;
    k->s2k.hash_algo = hash_algo;
    if( s2kmode == 1 || s2kmode == 3 ) {
        for(i=0; i < 8 && pktlen; i++, pktlen-- )
            k->s2k.salt[i] = gpg_iobuf_get_noeof(inp);
    }
    if( s2kmode == 3 ) {
        k->s2k.count = gpg_iobuf_get(inp); pktlen--;
    }
    k->seskeylen = seskeylen;
    for(i=0; i < seskeylen && pktlen; i++, pktlen-- )
        k->seskey[i] = gpg_iobuf_get_noeof(inp);
    assert( !pktlen );
    
    if( list_mode ) {
        printf(":symkey enc packet: version %d, cipher %d, s2k %d, hash %d\n",
               version, cipher_algo, s2kmode, hash_algo);
        if( s2kmode == 1 || s2kmode == 3 ) {
            printf("\tsalt ");
            for(i=0; i < 8; i++ )
                printf("%02x", k->s2k.salt[i]);
            if( s2kmode == 3 )
                printf(", count %lu\n", (ulong)k->s2k.count );
            printf("\n");
        }
    }
    
leave:
    skip_rest(inp, pktlen);
    return rc;
}

static int
parse_pubkeyenc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *packet )
{
    unsigned int n;
    int rc = 0;
    int i, ndata;
    PKT_pubkey_enc *k;
    
    k = packet->pkt.pubkey_enc = calloc(1, sizeof *packet->pkt.pubkey_enc);
    if( pktlen < 12 ) {
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    k->version = gpg_iobuf_get_noeof(inp); pktlen--;
    if( k->version != 2 && k->version != 3 ) {
        printf("packet(%d) with unknown version %d\n", pkttype, k->version);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    k->keyid[0] = read_32(inp); pktlen -= 4;
    k->keyid[1] = read_32(inp); pktlen -= 4;
    k->pubkey_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    k->throw_keyid = 0; /* only used as flag for build_packet */
    if( list_mode )
        printf(":pubkey enc packet: version %d, algo %d, keyid %08lX%08lX\n",
               k->version, k->pubkey_algo, (ulong)k->keyid[0], (ulong)k->keyid[1]);
    
    ndata = pubkey_get_nenc(k->pubkey_algo);
    if( !ndata ) {
        if( list_mode )
            printf("\tunsupported algorithm %d\n", k->pubkey_algo );
        unknown_pubkey_warning( k->pubkey_algo );
        k->data[0] = NULL;  /* no need to store the encrypted data */
    }
    else {
        for( i=0; i < ndata; i++ ) {
            n = pktlen;
            k->data[i] = mpi_read(inp, &n, 0); pktlen -=n;
            if( list_mode ) {
                printf("\tdata: ");
                mpi_print(stdout, k->data[i], mpi_print_mode );
                putchar('\n');
            }
            if (!k->data[i])
                rc = G10ERR_INVALID_PACKET;
        }
    }
    
leave:
    skip_rest(inp, pktlen);
    return rc;
}

static void
dump_sig_subpkt( int hashed, int type, int critical,
                 const byte *buffer, size_t buflen, size_t length )
{
    const char *p=NULL;
    int i;
    
    /* The CERT has warning out with explains how to use GNUPG to
     * detect the ARRs - we print our old message here when it is a faked
     * ARR and add an additional notice */
    if ( type == SIGSUBPKT_ARR && !hashed ) {
        printf("\tsubpkt %d len %u (additional recipient request)\n"
               "WARNING: PGP versions > 5.0 and < 6.5.8 will automagically "
               "encrypt to this key and thereby reveal the plaintext to "
               "the owner of this ARR key. Detailed info follows:\n",
               type, (unsigned)length );
    }
    
    
    printf("\t%s%ssubpkt %d len %u (", /*)*/
           critical ? "critical ":"",
           hashed ? "hashed ":"", type, (unsigned)length );
    buffer++;
    length--;
    if( length > buflen ) {
        printf("too short: buffer is only %u)\n", (unsigned)buflen );
        return;
    }
    switch( type ) {
    case SIGSUBPKT_SIG_CREATED:
        if( length >= 4 )
            printf("sig created %s", strtimestamp( buffer_to_u32(buffer) ) );
        break;
    case SIGSUBPKT_SIG_EXPIRE:
        if( length >= 4 )
            printf("sig expires after %s",
                   strtimevalue( buffer_to_u32(buffer) ) );
        break;
    case SIGSUBPKT_EXPORTABLE:
        if( length )
            printf("%sexportable", *buffer? "":"not ");
        break;
    case SIGSUBPKT_TRUST:
        if(length!=2)
            p="[invalid trust signature]";
        else
            printf("trust signature of level %d, amount %d",buffer[0],buffer[1]);
        break;
    case SIGSUBPKT_REGEXP:
        if(!length)
            p="[invalid regexp]";
        else
            printf("regular expression: \"%s\"",buffer);
        break;
    case SIGSUBPKT_REVOCABLE:
        if( length )
            printf("%srevocable", *buffer? "":"not ");
        break;
    case SIGSUBPKT_KEY_EXPIRE:
        if( length >= 4 )
            printf("key expires after %s",
                   strtimevalue( buffer_to_u32(buffer) ) );
        break;
    case SIGSUBPKT_PREF_SYM:
        fputs("pref-sym-algos:", stdout );
        for( i=0; i < length; i++ )
            printf(" %d", buffer[i] );
        break;
    case SIGSUBPKT_REV_KEY:
        fputs("revocation key: ", stdout );
        if( length < 22 )
            p = "[too short]";
        else {
            printf("c=%02x a=%d f=", buffer[0], buffer[1] );
            for( i=2; i < length; i++ )
                printf("%02X", buffer[i] );
        }
        break;
    case SIGSUBPKT_ISSUER:
        if( length >= 8 )
            printf("issuer key ID %08lX%08lX",
                   (ulong)buffer_to_u32(buffer),
                   (ulong)buffer_to_u32(buffer+4) );
        break;
    case SIGSUBPKT_NOTATION:
    {
        fputs("notation: ", stdout );
        if( length < 8 )
            p = "[too short]";
        else if( !(*buffer & 0x80) )
            p = "[not human readable]";
        else {
            const byte *s = buffer;
            size_t n1, n2;
            
            n1 = (s[4] << 8) | s[5];
            n2 = (s[6] << 8) | s[7];
            s += 8;
            if( 8+n1+n2 != length )
                p = "[error]";
            else {
                print_string( stdout, s, n1, ')' );
                putc( '=', stdout );
                print_string( stdout, s+n1, n2, ')' );
            }
        }
    }
    break;
    case SIGSUBPKT_PREF_HASH:
        fputs("pref-hash-algos:", stdout );
        for( i=0; i < length; i++ )
            printf(" %d", buffer[i] );
        break;
    case SIGSUBPKT_PREF_COMPR:
        fputs("pref-zip-algos:", stdout );
        for( i=0; i < length; i++ )
            printf(" %d", buffer[i] );
        break;
    case SIGSUBPKT_KS_FLAGS:
        fputs("key server preferences:",stdout);
        for(i=0;i<length;i++)
            printf(" %02X", buffer[i]);
        break;
    case SIGSUBPKT_PREF_KS:
        p = "preferred key server";
        break;
    case SIGSUBPKT_PRIMARY_UID:
        p = "primary user ID";
        break;
    case SIGSUBPKT_POLICY:
        fputs("policy: ", stdout );
        print_string( stdout, buffer, length, ')' );
        break;
    case SIGSUBPKT_KEY_FLAGS:
        fputs ( "key flags:", stdout );
        for( i=0; i < length; i++ )
            printf(" %02X", buffer[i] );
        break;
    case SIGSUBPKT_SIGNERS_UID:
        p = "signer's user ID";
        break;
    case SIGSUBPKT_REVOC_REASON:
        if( length ) {
            printf("revocation reason 0x%02x (", *buffer );
            print_string( stdout, buffer+1, length-1, ')' );
            p = ")";
        }
        break;
    case SIGSUBPKT_ARR:
        fputs("Big Brother's key (ignored): ", stdout );
        if( length < 22 )
            p = "[too short]";
        else {
            printf("c=%02x a=%d f=", buffer[0], buffer[1] );
            for( i=2; i < length; i++ )
                printf("%02X", buffer[i] );
        }
        break;
    case SIGSUBPKT_FEATURES:
        fputs ( "features:", stdout );
        for( i=0; i < length; i++ )
            printf(" %02x", buffer[i] );
        break;
    case SIGSUBPKT_PRIV_VERIFY_CACHE:
        p = "obsolete verification cache";
        break;
    default: p = "?"; break;
    }
    
    printf("%s)\n", p? p: "");
}

/****************
 * Returns: >= 0 offset into buffer
 *          -1 unknown type
 *          -2 unsupported type
 *          -3 subpacket too short
 */
int
parse_one_sig_subpkt( const byte *buffer, size_t n, int type )
{
    switch( type ) {
    case SIGSUBPKT_REV_KEY:
        if(n < 22)
            break;
        return 0;
    case SIGSUBPKT_SIG_CREATED:
    case SIGSUBPKT_SIG_EXPIRE:
    case SIGSUBPKT_KEY_EXPIRE:
        if( n < 4 )
            break;
        return 0;
    case SIGSUBPKT_KEY_FLAGS:
    case SIGSUBPKT_KS_FLAGS:
    case SIGSUBPKT_PREF_SYM:
    case SIGSUBPKT_PREF_HASH:
    case SIGSUBPKT_PREF_COMPR:
    case SIGSUBPKT_POLICY:
    case SIGSUBPKT_FEATURES:
        return 0;
    case SIGSUBPKT_EXPORTABLE:
    case SIGSUBPKT_REVOCABLE:
        if( !n )
            break;
        return 0;
    case SIGSUBPKT_ISSUER: /* issuer key ID */
        if( n < 8 )
            break;
        return 0;
    case SIGSUBPKT_NOTATION:
        if( n < 8 ) /* minimum length needed */
            break;
        return 0;
    case SIGSUBPKT_REVOC_REASON:
        if( !n  )
            break;
        return 0;
    case SIGSUBPKT_PRIMARY_UID:
        if ( n != 1 )
            break;
        return 0;   
    case SIGSUBPKT_PRIV_VERIFY_CACHE:
        /* We used this in gpg 1.0.5 and 1.0.6 to cache signature
         * verification results - it is no longer used.
         * "GPG" 0x00 <mode> <stat>
         * where mode == 1: valid data, stat == 0: invalid signature
         * stat == 1: valid signature 
         * (because we use private data, we check our marker) */
        if( n < 6 )
            break;
        if( buffer[0] != 'G' || buffer[1] != 'P'
            || buffer[2] != 'G' || buffer[3] )
            return -2;
        return 4;
    default: return -1;
    }
    return -3;
}


static int
can_handle_critical( const byte *buffer, size_t n, int type )
{
    switch( type ) {
    case SIGSUBPKT_NOTATION:
        if( n >= 8 && (*buffer & 0x80) )
            return 1; /* human readable is handled */
        return 0;
        
    case SIGSUBPKT_SIG_CREATED:
    case SIGSUBPKT_SIG_EXPIRE:
    case SIGSUBPKT_KEY_EXPIRE:
    case SIGSUBPKT_EXPORTABLE:
    case SIGSUBPKT_REVOCABLE:
    case SIGSUBPKT_REV_KEY:
    case SIGSUBPKT_ISSUER:/* issuer key ID */
    case SIGSUBPKT_PREF_SYM:
    case SIGSUBPKT_PREF_HASH:
    case SIGSUBPKT_PREF_COMPR:
    case SIGSUBPKT_KEY_FLAGS:
    case SIGSUBPKT_PRIMARY_UID:
    case SIGSUBPKT_FEATURES:
    case SIGSUBPKT_POLICY: /* Is it enough to show the policy? */
        return 1;
        
    default:
        return 0;
    }
}


const byte *
enum_sig_subpkt( const subpktarea_t *pktbuf, sigsubpkttype_t reqtype,
                 size_t *ret_n, int *start, int *critical )
{
    const byte *buffer;
    int buflen;
    int type;
    int critical_dummy;
    int offset;
    size_t n;
    int seq = 0;
    int reqseq = start? *start: 0;
    
    if(!critical)
        critical=&critical_dummy;
    
    if( !pktbuf || reqseq == -1 ) {
        /* return some value different from NULL to indicate that
         * there is no critical bit we do not understand.  The caller
         * will never use the value.  Yes I know, it is an ugly hack */
        return reqtype == SIGSUBPKT_TEST_CRITICAL? (const byte*)&pktbuf : NULL;
    }
    buffer = pktbuf->data;
    buflen = pktbuf->len;
    while( buflen ) {
        n = *buffer++; buflen--;
        if( n == 255 ) { /* 4 byte length header */
            if( buflen < 4 )
                goto too_short;
            n = (buffer[0] << 24) | (buffer[1] << 16)
                | (buffer[2] << 8) | buffer[3];
            buffer += 4;
            buflen -= 4;
        }
        else if( n >= 192 ) { /* 2 byte special encoded length header */
            if( buflen < 2 )
                goto too_short;
            n = (( n - 192 ) << 8) + *buffer + 192;
            buffer++;
            buflen--;
        }
        if( buflen < n )
            goto too_short;
        type = *buffer;
        if( type & 0x80 ) {
            type &= 0x7f;
            *critical = 1;
        }
        else
            *critical = 0;
        if( !(++seq > reqseq) )
            ;
        else if( reqtype == SIGSUBPKT_TEST_CRITICAL ) {
            if( *critical ) {
                if( n-1 > buflen+1 )
                    goto too_short;
                if( !can_handle_critical(buffer+1, n-1, type ) ) {
                    printf("subpacket of type %d has critical bit set\n",
                           type);
                    if( start )
                        *start = seq;
                    return NULL; /* this is an error */
                }
            }
        }
        else if( reqtype < 0 ) /* list packets */
            dump_sig_subpkt( reqtype == SIGSUBPKT_LIST_HASHED,
                             type, *critical, buffer, buflen, n );
        else if( type == reqtype ) { /* found */
            buffer++;
            n--;
            if( n > buflen )
                goto too_short;
            if( ret_n )
                *ret_n = n;
            offset = parse_one_sig_subpkt(buffer, n, type );
            switch( offset ) {
            case -3:
                printf("subpacket of type %d too short\n", type);
                return NULL;
            case -2:
                return NULL;
            case -1:
                printf( "This is a BUG.\n%s:%d\n", __FILE__, __LINE__ );
                exit( -1 );
            default:
                break;
            }
            if( start )
                *start = seq;
            return buffer+offset;
        }
        buffer += n; buflen -=n;
    }
    if( reqtype == SIGSUBPKT_TEST_CRITICAL )
        return buffer; /* as value true to indicate that there is no */
    /* critical bit we don't understand */
    if( start )
        *start = -1;
    return NULL; /* end of packets; not found */
    
too_short:
    printf("buffer shorter than subpacket\n");
    if( start )
        *start = -1;
    return NULL;
}


const byte *
gpg_parse_sig_subpkt (const subpktarea_t *buffer, sigsubpkttype_t reqtype,
                  size_t *ret_n)
{
    return enum_sig_subpkt( buffer, reqtype, ret_n, NULL, NULL );
}

const byte *
gpg_parse_sig_subpkt2 (PKT_signature *sig, sigsubpkttype_t reqtype,
                   size_t *ret_n )
{
    const byte *p;
    
    p = gpg_parse_sig_subpkt (sig->hashed, reqtype, ret_n );
    if( !p )
        p = gpg_parse_sig_subpkt (sig->unhashed, reqtype, ret_n );
    return p;
}

/* Find all revocation keys. Look in hashed area only. */
void parse_revkeys(PKT_signature *sig)
{
    struct revocation_key *revkey;
    int seq=0;
    size_t len;
    
    if( sig->sig_class != 0x1F )
        return;
    
    while((revkey=
           (struct revocation_key *)enum_sig_subpkt(sig->hashed,
                                                    SIGSUBPKT_REV_KEY,
                                                    &len,&seq,NULL))) {
        if( len==sizeof(struct revocation_key) &&
            (revkey->rclass&0x80)) /* 0x80 bit must be set */ {
            sig->revkey=realloc(sig->revkey,
                                  sizeof(struct revocation_key *)*(sig->numrevkeys+1));
            sig->revkey[sig->numrevkeys]=revkey;
            sig->numrevkeys++;
        }
    }
}

static int
parse_signature( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                          PKT_signature *sig )
{
    int md5_len=0;
    unsigned n;
    int is_v4=0;
    int rc=0;
    int i, ndata;
    
    if( pktlen < 16 ) {
        printf("packet(%d) too short\n", pkttype);
        goto leave;
    }
    sig->version = gpg_iobuf_get_noeof(inp); pktlen--;
    if( sig->version == 4 )
        is_v4=1;
    else if( sig->version != 2 && sig->version != 3 ) {
        printf("packet(%d) with unknown version %d\n", pkttype, sig->version);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    
    if( !is_v4 ) {
        md5_len = gpg_iobuf_get_noeof(inp); pktlen--;
    }
    sig->sig_class = gpg_iobuf_get_noeof(inp); pktlen--;
    if( !is_v4 ) {
        sig->timestamp = read_32(inp); pktlen -= 4;
        sig->keyid[0] = read_32(inp); pktlen -= 4;
        sig->keyid[1] = read_32(inp); pktlen -= 4;
    }
    sig->pubkey_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    sig->digest_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    sig->flags.exportable=1;
    sig->flags.revocable=1;
    if( is_v4 ) { /* read subpackets */
        n = read_16(inp); pktlen -= 2; /* length of hashed data */
        if( n > 10000 ) {
            printf("signature packet: hashed data too long\n");
            rc = G10ERR_INVALID_PACKET;
            goto leave;
        }
        if( n ) {
            sig->hashed = malloc (sizeof (*sig->hashed) + n - 1 );
            sig->hashed->size = n;
            sig->hashed->len = n;
            if( gpg_iobuf_read (inp, sig->hashed->data, n ) != n ) {
                printf ("premature eof while reading "
                        "hashed signature data\n");
                rc = -1;
                goto leave;
            }
            pktlen -= n;
        }
        n = read_16(inp); pktlen -= 2; /* length of unhashed data */
        if( n > 10000 ) {
            printf("signature packet: unhashed data too long\n");
            rc = G10ERR_INVALID_PACKET;
            goto leave;
        }
        if( n ) {
            /* we add 8 extra bytes so that we have space for the signature
             * status cache.  Well we are wastin this if there is a cache
             * packet already, but in the other case it avoids an realloc */
            sig->unhashed = malloc (sizeof(*sig->unhashed) + n + 8 - 1 );
            sig->unhashed->size = n + 8;
            sig->unhashed->len = n;
            if( gpg_iobuf_read(inp, sig->unhashed->data, n ) != n ) {
                printf("premature eof while reading "
                       "unhashed signature data\n");
                rc = -1;
                goto leave;
            }
            pktlen -= n;
        }
    }
    
    if( pktlen < 5 ) { /* sanity check */
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    
    sig->digest_start[0] = gpg_iobuf_get_noeof(inp); pktlen--;
    sig->digest_start[1] = gpg_iobuf_get_noeof(inp); pktlen--;
    
    if( is_v4 && sig->pubkey_algo ) { /*extract required information */
        const byte *p;
        
        /* set sig->flags.unknown_critical if there is a
         * critical bit set for packets which we do not understand */
        if( !gpg_parse_sig_subpkt (sig->hashed, SIGSUBPKT_TEST_CRITICAL, NULL)
            || !gpg_parse_sig_subpkt (sig->unhashed, SIGSUBPKT_TEST_CRITICAL,
                                  NULL) )
        {
            sig->flags.unknown_critical = 1;
        }
        
        p = gpg_parse_sig_subpkt (sig->hashed, SIGSUBPKT_SIG_CREATED, NULL );
        if( !p )
            printf("signature packet without timestamp\n");
        else
            sig->timestamp = buffer_to_u32(p);
        p = gpg_parse_sig_subpkt2( sig, SIGSUBPKT_ISSUER, NULL );
        if( !p )
            printf("signature packet without keyid\n");
        else {
            sig->keyid[0] = buffer_to_u32(p);
            sig->keyid[1] = buffer_to_u32(p+4);
        }
        
        p=gpg_parse_sig_subpkt(sig->hashed,SIGSUBPKT_SIG_EXPIRE,NULL);
        if(p)
            sig->expiredate=sig->timestamp+buffer_to_u32(p);
        if(sig->expiredate && sig->expiredate<=time(NULL))
            sig->flags.expired=1;
        
        p=gpg_parse_sig_subpkt(sig->hashed,SIGSUBPKT_POLICY,NULL);
        if(p)
            sig->flags.policy_url=1;
        
        p=gpg_parse_sig_subpkt(sig->hashed,SIGSUBPKT_NOTATION,NULL);
        if(p)
            sig->flags.notation=1;
        
        p=gpg_parse_sig_subpkt(sig->hashed,SIGSUBPKT_REVOCABLE,NULL);
        if(p && *p==0)
            sig->flags.revocable=0;
        
        /* We accept the exportable subpacket from either the hashed
           or unhashed areas as older versions of gpg put it in the
           unhashed area.  In theory, anyway, we should never see this
           packet off of a local keyring. */
        
        p=gpg_parse_sig_subpkt2(sig,SIGSUBPKT_EXPORTABLE,NULL);
        if(p && *p==0)
            sig->flags.exportable=0;
        
        /* Find all revocation keys. */
        if(sig->sig_class==0x1F)
            parse_revkeys(sig);
    }
    
    if( list_mode ) {
        printf(":signature packet: algo %d, keyid %08lX%08lX\n"
               "\tversion %d, created %lu, md5len %d, sigclass %02x\n"
               "\tdigest algo %d, begin of digest %02x %02x\n",
               sig->pubkey_algo,
               (ulong)sig->keyid[0], (ulong)sig->keyid[1],
               sig->version, (ulong)sig->timestamp, md5_len, sig->sig_class,
               sig->digest_algo,
               sig->digest_start[0], sig->digest_start[1] );
        if( is_v4 ) {
            gpg_parse_sig_subpkt (sig->hashed,   SIGSUBPKT_LIST_HASHED, NULL );
            gpg_parse_sig_subpkt (sig->unhashed, SIGSUBPKT_LIST_UNHASHED, NULL);
        }
    }
    
    ndata = pubkey_get_nsig(sig->pubkey_algo);
    if( !ndata ) {
        if( list_mode )
            printf("\tunknown algorithm %d\n", sig->pubkey_algo );
        unknown_pubkey_warning( sig->pubkey_algo );
        /* we store the plain material in data[0], so that we are able
         * to write it back with build_packet() */
        sig->data[0] = mpi_set_opaque(NULL, read_rest(inp, pktlen), pktlen );
        pktlen = 0;
    }
    else {
        for( i=0; i < ndata; i++ ) {
            n = pktlen;
            sig->data[i] = mpi_read(inp, &n, 0 );
            pktlen -=n;
            if( list_mode ) {
                printf("\tdata: ");
                mpi_print(stdout, sig->data[i], mpi_print_mode );
                putchar('\n');
            }
            if (!sig->data[i])
                rc = G10ERR_INVALID_PACKET;
        }
    }
    
leave:
    skip_rest(inp, pktlen);
    return rc;
}


static int
parse_onepass_sig( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                             PKT_onepass_sig *ops )
{
    int version;
    int rc = 0;
    
    if( pktlen < 13 ) {
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    version = gpg_iobuf_get_noeof(inp); pktlen--;
    if( version != 3 ) {
        printf("onepass_sig with unknown version %d\n", version);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    ops->sig_class = gpg_iobuf_get_noeof(inp); pktlen--;
    ops->digest_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    ops->pubkey_algo = gpg_iobuf_get_noeof(inp); pktlen--;
    ops->keyid[0] = read_32(inp); pktlen -= 4;
    ops->keyid[1] = read_32(inp); pktlen -= 4;
    ops->last = gpg_iobuf_get_noeof(inp); pktlen--;
    if( list_mode )
        printf(":onepass_sig packet: keyid %08lX%08lX\n"
               "\tversion %d, sigclass %02x, digest %d, pubkey %d, last=%d\n",
               (ulong)ops->keyid[0], (ulong)ops->keyid[1],
               version, ops->sig_class,
               ops->digest_algo, ops->pubkey_algo, ops->last );
    
    
leave:
    skip_rest(inp, pktlen);
    return rc;
}


static int
parse_key( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                              byte *hdr, int hdrlen, PACKET *pkt )
{
    int i, version, algorithm;
    unsigned n;
    unsigned long timestamp, expiredate, max_expiredate;
    int npkey, nskey;
    int is_v4=0;
    int rc=0;

    version = gpg_iobuf_get_noeof(inp); pktlen--;
    if( pkttype == PKT_PUBLIC_SUBKEY && version == '#' ) {
        /* early versions of G10 use old PGP comments packets;
         * luckily all those comments are started by a hash */
        if( list_mode ) {
            printf(":rfc1991 comment packet: \"" );
            for( ; pktlen; pktlen-- ) {
                int c;
                c = gpg_iobuf_get_noeof(inp);
                if( c >= ' ' && c <= 'z' )
                    putchar(c);
                else
                    printf("\\x%02x", c );
            }
            printf("\"\n");
        }
        skip_rest(inp, pktlen);
        return 0;
    }
    else if( version == 4 )
        is_v4=1;
    else if( version != 2 && version != 3 ) {
        printf("packet(%d) with unknown version %d\n", pkttype, version);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }

    if( pktlen < 11 ) {
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }

    timestamp = read_32(inp); pktlen -= 4;
    if( is_v4 ) {
        expiredate = 0; /* have to get it from the selfsignature */
        max_expiredate = 0;
    }
    else {
        unsigned short ndays;
        ndays = read_16(inp); pktlen -= 2;
        if( ndays )
            expiredate = timestamp + ndays * 86400L;
        else
            expiredate = 0;

        max_expiredate=expiredate;
    }
    algorithm = gpg_iobuf_get_noeof(inp); pktlen--;
    if( list_mode )
        printf(":%s key packet:\n"
               "\tversion %d, algo %d, created %lu, expires %lu\n",
                pkttype == PKT_PUBLIC_KEY? "public" :
                pkttype == PKT_SECRET_KEY? "secret" :
                pkttype == PKT_PUBLIC_SUBKEY? "public sub" :
                pkttype == PKT_SECRET_SUBKEY? "secret sub" : "??",
                version, algorithm, timestamp, expiredate );

    if( pkttype == PKT_SECRET_KEY || pkttype == PKT_SECRET_SUBKEY )  {
        PKT_secret_key *sk = pkt->pkt.secret_key;

        sk->timestamp = timestamp;
        sk->expiredate = expiredate;
        sk->max_expiredate = max_expiredate;
        sk->hdrbytes = hdrlen;
        sk->version = version;
        sk->is_primary = pkttype == PKT_SECRET_KEY;
        sk->pubkey_algo = algorithm;
        sk->req_usage = 0; 
        sk->pubkey_usage = 0; /* not yet used */
    }
    else {
        PKT_public_key *pk = pkt->pkt.public_key;

        pk->timestamp = timestamp;
        pk->expiredate = expiredate;
        pk->max_expiredate = max_expiredate;
        pk->hdrbytes    = hdrlen;
        pk->version     = version;
        pk->is_primary = pkttype == PKT_PUBLIC_KEY;
        pk->pubkey_algo = algorithm;
        pk->req_usage = 0; 
        pk->pubkey_usage = 0; /* not yet used */
        pk->is_revoked = 0;     
        pk->keyid[0] = 0;
        pk->keyid[1] = 0;
    }
    nskey = pubkey_get_nskey( algorithm );
    npkey = pubkey_get_npkey( algorithm );
    if( !npkey ) {
        if( list_mode )
            printf("\tunknown algorithm %d\n", algorithm );
        unknown_pubkey_warning( algorithm );
    }


    if( pkttype == PKT_SECRET_KEY || pkttype == PKT_SECRET_SUBKEY ) {
        PKT_secret_key *sk = pkt->pkt.secret_key;
        byte temp[16];
        size_t snlen = 0;

        if( !npkey ) {
            sk->skey[0] = mpi_set_opaque( NULL,
                                          read_rest(inp, pktlen), pktlen );
            pktlen = 0;
            goto leave;
        }

        for(i=0; i < npkey; i++ ) {
            n = pktlen; sk->skey[i] = mpi_read(inp, &n, 0 ); pktlen -=n;
            if( list_mode ) {
                printf(  "\tskey[%d]: ", i);
                mpi_print(stdout, sk->skey[i], mpi_print_mode  );
                putchar('\n');
            }
            if (!sk->skey[i])
                rc = G10ERR_INVALID_PACKET;
        }
        if (rc) /* one of the MPIs were bad */
            goto leave;
        sk->protect.algo = gpg_iobuf_get_noeof(inp); pktlen--;
        sk->protect.sha1chk = 0;
        if( sk->protect.algo ) {
            sk->is_protected = 1;
            sk->protect.s2k.count = 0;
            if( sk->protect.algo == 254 || sk->protect.algo == 255 ) {
                if( pktlen < 3 ) {
                    rc = G10ERR_INVALID_PACKET;
                    goto leave;
                }
                sk->protect.sha1chk = (sk->protect.algo == 254);
                sk->protect.algo = gpg_iobuf_get_noeof(inp); pktlen--;
                /* Note that a sk->protect.algo > 110 is illegal, but
                   I'm not erroring on it here as otherwise there
                   would be no way to delete such a key. */
                sk->protect.s2k.mode  = gpg_iobuf_get_noeof(inp); pktlen--;
                sk->protect.s2k.hash_algo = gpg_iobuf_get_noeof(inp); pktlen--;
                /* check for the special GNU extension */
                if( is_v4 && sk->protect.s2k.mode == 101 ) {
                    for(i=0; i < 4 && pktlen; i++, pktlen-- )
                        temp[i] = gpg_iobuf_get_noeof(inp);
                    if( i < 4 || memcmp( temp, "GNU", 3 ) ) {
                        if( list_mode )
                            printf(  "\tunknown S2K %d\n",
                                                sk->protect.s2k.mode );
                        rc = G10ERR_INVALID_PACKET;
                        goto leave;
                    }
                    /* here we know that it is a gnu extension
                     * What follows is the GNU protection mode:
                     * All values have special meanings
                     * and they are mapped in the mode with a base of 1000.
                     */
                    sk->protect.s2k.mode = 1000 + temp[3];
                }
                switch( sk->protect.s2k.mode ) {
                  case 1:
                  case 3:
                    for(i=0; i < 8 && pktlen; i++, pktlen-- )
                        temp[i] = gpg_iobuf_get_noeof(inp);
                    memcpy(sk->protect.s2k.salt, temp, 8 );
                    break;
                }
                switch( sk->protect.s2k.mode ) {
                  case 0: if( list_mode ) printf(  "\tsimple S2K" );
                    break;
                  case 1: if( list_mode ) printf(  "\tsalted S2K" );
                    break;
                  case 3: if( list_mode ) printf(  "\titer+salt S2K" );
                    break;
                  case 1001: if( list_mode ) printf(  "\tgnu-dummy S2K" );
                    break;
                  case 1002: if (list_mode) printf("\tgnu-divert-to-card S2K");
                    break;
                  default:
                    if( list_mode )
                        printf(  "\tunknown %sS2K %d\n",
                                 sk->protect.s2k.mode < 1000? "":"GNU ",
                                                   sk->protect.s2k.mode );
                    rc = G10ERR_INVALID_PACKET;
                    goto leave;
                }

                if( list_mode ) {
                    printf(", algo: %d,%s hash: %d",
                                     sk->protect.algo,
                                     sk->protect.sha1chk?" SHA1 protection,"
                                                        :" simple checksum,",
                                     sk->protect.s2k.hash_algo );
                    if( sk->protect.s2k.mode == 1
                        || sk->protect.s2k.mode == 3 ) {
                        printf(", salt: ");
                        for(i=0; i < 8; i++ )
                            printf("%02x", sk->protect.s2k.salt[i]);
                    }
                    putchar('\n');
                }

                if( sk->protect.s2k.mode == 3 ) {
                    if( pktlen < 1 ) {
                        rc = G10ERR_INVALID_PACKET;
                        goto leave;
                    }
                    sk->protect.s2k.count = gpg_iobuf_get(inp);
                    pktlen--;
                    if( list_mode )
                        printf("\tprotect count: %lu\n",
                                            (ulong)sk->protect.s2k.count);
                }
                else if( sk->protect.s2k.mode == 1002 ) {
                    /* Read the serial number. */
                    if (pktlen < 1) {
                      rc = G10ERR_INVALID_PACKET;
                        goto leave;
                    }
                    snlen = gpg_iobuf_get (inp);
                    pktlen--;
                    if (pktlen < snlen || snlen == -1) {
                        rc = G10ERR_INVALID_PACKET;
                        goto leave;
                    }
                }
            }
            /* Note that a sk->protect.algo > 110 is illegal, but I'm
               not erroring on it here as otherwise there would be no
               way to delete such a key. */
            else { /* old version; no S2K, so we set mode to 0, hash MD5 */
                sk->protect.s2k.mode = 0;
                sk->protect.s2k.hash_algo = DIGEST_ALGO_MD5;
                if( list_mode )
                    printf(  "\tprotect algo: %d  (hash algo: %d)\n",
                         sk->protect.algo, sk->protect.s2k.hash_algo );
            }
            /* It is really ugly that we don't know the size
             * of the IV here in cases we are not aware of the algorithm.
             * so a
             *   sk->protect.ivlen = cipher_get_blocksize(sk->protect.algo);
             * won't work.  The only solution I see is to hardwire it here.
             * NOTE: if you change the ivlen above 16, don't forget to
             * enlarge temp.
             */
            switch( sk->protect.algo ) {
              case 7: case 8: case 9: /* reserved for AES */
              case 10: /* Twofish */
                sk->protect.ivlen = 16;
                break;
              default:
                sk->protect.ivlen = 8;
            }
            if( sk->protect.s2k.mode == 1001 )
                sk->protect.ivlen = 0;
            else if( sk->protect.s2k.mode == 1002 )
                sk->protect.ivlen = snlen < 16? snlen : 16;

            if( pktlen < sk->protect.ivlen ) {
                rc = G10ERR_INVALID_PACKET;
                goto leave;
            }
            for(i=0; i < sk->protect.ivlen && pktlen; i++, pktlen-- )
                temp[i] = gpg_iobuf_get_noeof(inp);
            if( list_mode ) {
                printf( sk->protect.s2k.mode == 1002? "\tserial-number: "
                                                    : "\tprotect IV: ");
                for(i=0; i < sk->protect.ivlen; i++ )
                    printf(" %02x", temp[i] );
                putchar('\n');
            }
            memcpy( sk->protect.iv, temp, sk->protect.ivlen );
        }
        else
            sk->is_protected = 0;
        /* It does not make sense to read it into secure memory.
         * If the user is so careless, not to protect his secret key,
         * we can assume, that he operates an open system :=(.
         * So we put the key into secure memory when we unprotect it. */
        if( sk->protect.s2k.mode == 1001 
            || sk->protect.s2k.mode == 1002 ) {
            /* better set some dummy stuff here */
            sk->skey[npkey] = mpi_set_opaque(NULL, strdup("dummydata"), 10);
            pktlen = 0;
        }
        else if( is_v4 && sk->is_protected ) {
            /* ugly; the length is encrypted too, so we read all
             * stuff up to the end of the packet into the first
             * skey element */
            sk->skey[npkey] = mpi_set_opaque(NULL,
                                             read_rest(inp, pktlen), pktlen );
            pktlen = 0;
            if( list_mode ) {
                printf("\tencrypted stuff follows\n");
            }
        }
        else { /* v3 method: the mpi length is not encrypted */
            for(i=npkey; i < nskey; i++ ) {
                n = pktlen; sk->skey[i] = mpi_read(inp, &n, 0 ); pktlen -=n;
                if( sk->is_protected && sk->skey[i] )
                    mpi_set_protect_flag(sk->skey[i]);
                if( list_mode ) {
                    printf(  "\tskey[%d]: ", i);
                    if( sk->is_protected )
                        printf(  "[encrypted]\n");
                    else {
                        mpi_print(stdout, sk->skey[i], mpi_print_mode  );
                        putchar('\n');
                    }
                }
                if (!sk->skey[i])
                    rc = G10ERR_INVALID_PACKET;
            }
            if (rc)
                goto leave;
            
            sk->csum = read_16(inp); pktlen -= 2;
            if( list_mode ) {
                printf("\tchecksum: %04hx\n", sk->csum);
            }
        }
    }
    else {
        PKT_public_key *pk = pkt->pkt.public_key;

        if( !npkey ) {
            pk->pkey[0] = mpi_set_opaque( NULL,
                                          read_rest(inp, pktlen), pktlen );
            pktlen = 0;
            goto leave;
        }

        for(i=0; i < npkey; i++ ) {
            n = pktlen; pk->pkey[i] = mpi_read(inp, &n, 0 ); pktlen -=n;
            if( list_mode ) {
                printf(  "\tpkey[%d]: ", i);
                mpi_print(stdout, pk->pkey[i], mpi_print_mode  );
                putchar('\n');
            }
            if (!pk->pkey[i])
                rc = G10ERR_INVALID_PACKET;
        }
        if (rc)
            goto leave;
    }

  leave:
    skip_rest(inp, pktlen);
    return rc;
}

/* Attribute subpackets have the same format as v4 signature
   subpackets.  This is not part of OpenPGP, but is done in several
   versions of PGP nevertheless. */
int
parse_attribute_subpkts(PKT_user_id *uid)
{
    size_t n;
    int count=0;
    struct user_attribute *attribs=NULL;
    const byte *buffer=uid->attrib_data;
    int buflen=uid->attrib_len;
    byte type;
    
    safe_free(uid->attribs);
    
    while(buflen) {
        n = *buffer++; buflen--;
        if( n == 255 ) { /* 4 byte length header */
            if( buflen < 4 )
                goto too_short;
            n = (buffer[0] << 24) | (buffer[1] << 16)
                | (buffer[2] << 8) | buffer[3];
            buffer += 4;
            buflen -= 4;
        }
        else if( n >= 192 ) { /* 2 byte special encoded length header */
            if( buflen < 2 )
                goto too_short;
            n = (( n - 192 ) << 8) + *buffer + 192;
            buffer++;
            buflen--;
        }
        if( buflen < n )
            goto too_short;
        
        attribs=realloc(attribs,(count+1)*sizeof(struct user_attribute));
        memset(&attribs[count],0,sizeof(struct user_attribute));
        
        type=*buffer;
        buffer++;
        buflen--;
        n--;
        
        attribs[count].type=type;
        attribs[count].data=buffer;
        attribs[count].len=n;
        buffer+=n;
        buflen-=n;
        count++;
    }
    
    uid->attribs=attribs;
    uid->numattribs=count;
    return count;
    
too_short:
    printf("buffer shorter than attribute subpacket\n");
    uid->attribs=attribs;
    uid->numattribs=count;
    return count;
}

static void
setup_user_id(PACKET *packet)
{
    packet->pkt.user_id->ref = 1;
    packet->pkt.user_id->attribs = NULL;
    packet->pkt.user_id->attrib_data = NULL;
    packet->pkt.user_id->attrib_len = 0;
    packet->pkt.user_id->is_primary = 0;
    packet->pkt.user_id->is_revoked = 0;
    packet->pkt.user_id->is_expired = 0;
    packet->pkt.user_id->expiredate = 0;
    packet->pkt.user_id->created = 0;
    packet->pkt.user_id->help_key_usage = 0;
    packet->pkt.user_id->help_key_expire = 0;
    packet->pkt.user_id->prefs = NULL;
}

static int
parse_user_id( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *packet )
{
    byte *p;
    
    packet->pkt.user_id = malloc(sizeof *packet->pkt.user_id  + pktlen);
    packet->pkt.user_id->len = pktlen;
    
    setup_user_id(packet);
    
    p = packet->pkt.user_id->name;
    for( ; pktlen; pktlen--, p++ )
        *p = gpg_iobuf_get_noeof(inp);
    *p = 0;
    
    if( list_mode ) {
        int n = packet->pkt.user_id->len;
        printf(":user ID packet: \"");
        /* fixme: Hey why don't we replace this with print_string?? */
        for(p=packet->pkt.user_id->name; n; p++, n-- ) {
            if( *p >= ' ' && *p <= 'z' )
                putchar(*p);
            else
                printf("\\x%02x", *p );
        }
        printf("\"\n");
    }
    return 0;
}

/* Returns 0 for error, 1 for valid */
int parse_image_header(const struct user_attribute *attr,byte *type,u32 *len)
{
    u16 headerlen;
    
    if(attr->len<3)
        return 0;
    
    /* For historical reasons (i.e. "oops!"), the header length is
       little endian. */
    headerlen=(attr->data[1]<<8) | attr->data[0];
    
    if(headerlen>attr->len)
        return 0;
    
    if(type && attr->len>=4)
    {
        if(attr->data[2]==1) /* header version 1 */
            *type=attr->data[3];
        else
            *type=0;
    }
    
    *len=attr->len-headerlen;
    
    if(*len==0)
        return 0;
    
    return 1;
}

/* style==0 for extension, 1 for name, 2 for MIME type.  Remember that
   the "name" style string could be used in a user ID name field, so
   make sure it is not too big (see
   parse-packet.c:parse_attribute). */
char *image_type_to_string(byte type,int style)
{
    char *string;
    
    switch(type) {
    case 1: /* jpeg */
        if(style==0)
            string="jpg";
        else if(style==1)
            string="jpeg";
        else
            string="image/jpeg";
        break;
        
    default:
        if(style==0)
            string="bin";
        else if(style==1)
            string="unknown";
        else
            string="image/x-unknown";
        break;
    }
    
    return string;
}

void
make_attribute_uidname(PKT_user_id *uid)
{
    if(uid->numattribs<=0)
        sprintf(uid->name,"[bad attribute packet of size %lu]",uid->attrib_len);
    else if(uid->numattribs>1)
        sprintf(uid->name,"[%d attributes of size %lu]",
                uid->numattribs,uid->attrib_len);
    else {
        /* Only one attribute, so list it as the "user id" */
        
        if(uid->attribs->type==ATTRIB_IMAGE) {
            u32 len;
            byte type;
            
            if(parse_image_header(uid->attribs,&type,&len))
                sprintf(uid->name,"[%s image of size %lu]",
                        image_type_to_string(type,1),(ulong)len);
            else
                sprintf(uid->name,"[invalid image]");
        }
        else
            sprintf(uid->name,"[unknown attribute of size %lu]",
                    (ulong)uid->attribs->len);
    }
    
    uid->len = strlen(uid->name);
}

static int
parse_attribute( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *packet )
{
    byte *p;
    
    packet->pkt.user_id = malloc(sizeof *packet->pkt.user_id + 70);
    
    setup_user_id(packet);
    
    packet->pkt.user_id->attrib_data = malloc(pktlen);
    packet->pkt.user_id->attrib_len = pktlen;
    p = packet->pkt.user_id->attrib_data;
    for( ; pktlen; pktlen--, p++ )
        *p = gpg_iobuf_get_noeof(inp);
    
    /* Now parse out the individual attribute subpackets.  This is
       somewhat pointless since there is only one currently defined
       attribute type (jpeg), but it is correct by the spec. */
    parse_attribute_subpkts(packet->pkt.user_id);
    
    make_attribute_uidname(packet->pkt.user_id);
    
    if( list_mode ) {
        printf(":attribute packet: %s\n", packet->pkt.user_id->name );
    }
    return 0;
}


static int
parse_comment( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *packet )
{
    byte *p;
    
    packet->pkt.comment = malloc(sizeof *packet->pkt.comment + pktlen - 1);
    packet->pkt.comment->len = pktlen;
    p = packet->pkt.comment->data;
    for( ; pktlen; pktlen--, p++ )
        *p = gpg_iobuf_get_noeof(inp);
    
    if( list_mode ) {
        int n = packet->pkt.comment->len;
        printf(":%scomment packet: \"", pkttype == PKT_OLD_COMMENT?
               "OpenPGP draft " : "" );
        for(p=packet->pkt.comment->data; n; p++, n-- ) {
            if( *p >= ' ' && *p <= 'z' )
                putchar(*p);
            else
                printf("\\x%02x", *p );
        }
        printf("\"\n");
    }
    return 0;
}


static void
parse_trust( gpg_iobuf_t inp, int pkttype, unsigned long pktlen, PACKET *pkt )
{
    int c;
    
    if (pktlen) {
        c = gpg_iobuf_get_noeof(inp);
        pktlen--;
        pkt->pkt.ring_trust = malloc( sizeof *pkt->pkt.ring_trust );
        pkt->pkt.ring_trust->trustval = c;
        pkt->pkt.ring_trust->sigcache = 0;
        if (!c && pktlen==1) {
            c = gpg_iobuf_get_noeof (inp);
            pktlen--;
            /* we require that bit 7 of the sigcache is 0 (easier eof handling)*/
            if ( !(c & 0x80) )
                pkt->pkt.ring_trust->sigcache = c;
        }
        if( list_mode )
            printf(":trust packet: flag=%02x sigcache=%02x\n",
                   pkt->pkt.ring_trust->trustval,
                   pkt->pkt.ring_trust->sigcache);
    }
    else {
        if( list_mode )
            printf(":trust packet: empty\n");
    }
    skip_rest (inp, pktlen);
}


static int
parse_plaintext( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                        PACKET *pkt, int new_ctb )
{
    int rc = 0;
    int mode, namelen, partial=0;
    PKT_plaintext *pt;
    byte *p;
    int c, i;
    
    if( pktlen && pktlen < 6 ) {
        printf("packet(%d) too short (%lu)\n", pkttype, (ulong)pktlen);
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    /* A packet length of zero indicates partial body length.  A zero
       data length isn't a zero length packet due to the header (mode,
       name, etc), so this is accurate. */
    if(pktlen==0)
        partial=1;
    mode = gpg_iobuf_get_noeof(inp); if( pktlen ) pktlen--;
    namelen = gpg_iobuf_get_noeof(inp); if( pktlen ) pktlen--;
    pt = pkt->pkt.plaintext = malloc(sizeof *pkt->pkt.plaintext + namelen -1);
    pt->new_ctb = new_ctb;
    pt->mode = mode;
    pt->namelen = namelen;
    pt->is_partial = partial;
    if( pktlen ) {
        for( i=0; pktlen > 4 && i < namelen; pktlen--, i++ )
            pt->name[i] = gpg_iobuf_get_noeof(inp);
    }
    else {
        for( i=0; i < namelen; i++ )
            if( (c=gpg_iobuf_get(inp)) == -1 )
                break;
            else
                pt->name[i] = c;
    }
    pt->timestamp = read_32(inp); if( pktlen) pktlen -= 4;
    pt->len = pktlen;
    pt->buf = inp;
    pktlen = 0;
    
    if( list_mode ) {
        printf(":literal data packet:\n"
               "\tmode %c, created %lu, name=\"",
               mode >= ' ' && mode <'z'? mode : '?',
               (ulong)pt->timestamp );
        for(p=pt->name,i=0; i < namelen; p++, i++ ) {
            if( *p >= ' ' && *p <= 'z' )
                putchar(*p);
            else
                printf("\\x%02x", *p );
        }
        printf("\",\n\traw data: %lu bytes\n", (ulong)pt->len );
    }
    
leave:
    return rc;
}


static int
parse_compressed( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                  PACKET *pkt, int new_ctb )
{
    PKT_compressed *zd;
    
    /* pktlen is here 0, but data follows
     * (this should be the last object in a file or
     *  the compress algorithm should know the length)
     */
    zd = pkt->pkt.compressed =  malloc(sizeof *pkt->pkt.compressed );
    zd->algorithm = gpg_iobuf_get_noeof(inp);
    zd->len = 0; /* not used */ 
    zd->new_ctb = new_ctb;
    zd->buf = inp;
    if( list_mode )
        printf(":compressed packet: algo=%d\n", zd->algorithm);
    return 0;
}


static int
parse_encrypted( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                       PACKET *pkt, int new_ctb )
{
    int rc = 0;
    PKT_encrypted *ed;
    unsigned long orig_pktlen = pktlen;
    
    ed = pkt->pkt.encrypted =  malloc(sizeof *pkt->pkt.encrypted );
    ed->len = pktlen;
    /* we don't know the extralen which is (cipher_blocksize+2)
       because the algorithm ist not specified in this packet.
       However, it is only important to know this for some sanity
       checks on the packet length - it doesn't matter that we can't
       do it */
    ed->extralen = 0;
    ed->buf = NULL;
    ed->new_ctb = new_ctb;
    ed->mdc_method = 0;
    if( pkttype == PKT_ENCRYPTED_MDC ) {
        /* fixme: add some pktlen sanity checks */
        int version;
        
        version = gpg_iobuf_get_noeof(inp); 
        if (orig_pktlen)
            pktlen--;
        if( version != 1 ) {
            printf("encrypted_mdc packet with unknown version %d\n",
                   version);
            /*skip_rest(inp, pktlen); should we really do this? */
            rc = G10ERR_INVALID_PACKET;
            goto leave;
        }
        ed->mdc_method = DIGEST_ALGO_SHA1;
    }
    if( orig_pktlen && pktlen < 10 ) { /* actually this is blocksize+2 */
        printf("packet(%d) too short\n", pkttype);
        rc = G10ERR_INVALID_PACKET;
        skip_rest(inp, pktlen);
        goto leave;
    }
    if( list_mode ) {
        if( orig_pktlen )
            printf(":encrypted data packet:\n\tlength: %lu\n", orig_pktlen);
        else
            printf(":encrypted data packet:\n\tlength: unknown\n");
        if( ed->mdc_method )
            printf("\tmdc_method: %d\n", ed->mdc_method );
    }
    
    ed->buf = inp;
    pktlen = 0;
    
leave:
    return rc;
}


static int
parse_mdc( gpg_iobuf_t inp, int pkttype, unsigned long pktlen,
                                   PACKET *pkt, int new_ctb )
{
    int rc = 0;
    PKT_mdc *mdc;
    byte *p;
    
    mdc = pkt->pkt.mdc=  malloc(sizeof *pkt->pkt.mdc );
    if( list_mode )
        printf(":mdc packet: length=%lu\n", pktlen);
    if( !new_ctb || pktlen != 20 ) {
        printf("mdc_packet with invalid encoding\n");
        rc = G10ERR_INVALID_PACKET;
        goto leave;
    }
    p = mdc->hash;
    for( ; pktlen; pktlen--, p++ )
        *p = gpg_iobuf_get_noeof(inp);
    
leave:
    return rc;
}


/*
 * This packet is internally generated by PGG (by armor.c) to
 * transfer some information to the lower layer.  To make sure that
 * this packet is really a GPG faked one and not one comming from outside,
 * we first check that tehre is a unique tag in it.
 * The format of such a control packet is:
 *   n byte  session marker
 *   1 byte  control type CTRLPKT_xxxxx
 *   m byte  control data
 */

/* Return a string which is used as a kind of process ID */
const byte *
get_session_marker( size_t *rlen )
{
    static byte marker[SIZEOF_UNSIGNED_LONG*2];
    static int initialized;
    
    if ( !initialized ) {
        volatile ulong aa, bb; /* we really want the uninitialized value */
        ulong a, b;
        
        initialized = 1;
        /* also this marker is guessable it is not easy to use this 
         * for a faked control packet because an attacker does not
         * have enough control about the time the verification does 
         * take place.  Of course, we can add just more random but 
         * than we need the random generator even for verification
         * tasks - which does not make sense. */
        a = aa ^ (ulong)getpid();
        b = bb ^ (ulong)time(NULL);
        memcpy( marker, &a, SIZEOF_UNSIGNED_LONG );
        memcpy( marker+SIZEOF_UNSIGNED_LONG, &b, SIZEOF_UNSIGNED_LONG );
    }
    *rlen = sizeof(marker);
    return marker;
}

static int
parse_gpg_control( gpg_iobuf_t inp,
                   int pkttype, unsigned long pktlen, PACKET *packet )
{
    byte *p;
    const byte *sesmark;
    size_t sesmarklen;
    int i;
    
    if ( list_mode )
        printf(":packet 63: length %lu ",  pktlen);
    
    sesmark = get_session_marker ( &sesmarklen );
    if ( pktlen < sesmarklen+1 ) /* 1 is for the control bytes */
        goto skipit;
    for( i=0; i < sesmarklen; i++, pktlen-- ) {
        if ( sesmark[i] != gpg_iobuf_get_noeof(inp) )
            goto skipit;
    }
    if ( list_mode )
        puts ("- gpg control packet");
    
    packet->pkt.gpg_control = malloc(sizeof *packet->pkt.gpg_control
                                      + pktlen - 1);
    packet->pkt.gpg_control->control = gpg_iobuf_get_noeof(inp); pktlen--;
    packet->pkt.gpg_control->datalen = pktlen;
    p = packet->pkt.gpg_control->data;
    for( ; pktlen; pktlen--, p++ )
        *p = gpg_iobuf_get_noeof(inp);
    
    return 0;
    
skipit:
    if ( list_mode ) {
        int c;
        
        i=0;
        printf("- private (rest length %lu)\n",  pktlen);
        if( gpg_iobuf_in_block_mode(inp) ) {
            while( (c=gpg_iobuf_get(inp)) != -1 )
                dump_hex_line(c, &i);
        }
        else {
            for( ; pktlen; pktlen-- )
                dump_hex_line(gpg_iobuf_get(inp), &i);
        }
        putchar('\n');
    }
    skip_rest(inp,pktlen);
    return G10ERR_INVALID_PACKET;
}


u32
gpg_keyid_from_pk( PKT_public_key * pk, byte *fprint )
{
    gpg_md_t md;
    int npkey, pktlen, i;
    const byte *mdbuf;
        
    if( pk->version == 3 && pk->pubkey_algo == PUBKEY_ALGO_RSA )
        return pk->pkey[0]->d[0];
    else {
        md = gpg_md_open( DIGEST_ALGO_SHA1 );
        gpg_md_putc( md, 0x99 );
        npkey = pubkey_get_npkey( pk->pubkey_algo );
        pktlen = 6;
        for( i = 0 ; i <npkey; i++ )
            pktlen = pktlen + 2 + pk->pkey[i]->alloced;
        gpg_md_putc( md, pktlen>>8 );
        gpg_md_putc( md, pktlen );
        gpg_md_putc( md, 4 );
        gpg_md_putc( md, pk->timestamp >> 24 );
        gpg_md_putc( md, pk->timestamp >> 16 );
        gpg_md_putc( md, pk->timestamp >>  8 );
        gpg_md_putc( md, pk->timestamp       );
        gpg_md_putc( md, pk->pubkey_algo );
        for( i=0; i <npkey; i++ ) {
            const u32 * d = pk->pkey[i]->d;
            int nbits = pk->pkey[i]->nbits,
                n = pk->pkey[i]->alloced;
            gpg_md_putc( md, nbits >> 8 );
            gpg_md_putc( md, nbits );
            n = n>4? n/4 : n;
            while( n-- ) {
                if( pk->pkey[i]->alloced > 3 )
                    gpg_md_putc( md, d[n] >> 24 );
                if( pk->pkey[i]->alloced > 2 )
                    gpg_md_putc( md, d[n] >> 16 );
                if( pk->pkey[i]->alloced > 1 )
                    gpg_md_putc( md, d[n] >>  8 );
                if( pk->pkey[i]->alloced > 0 )
                    gpg_md_putc( md, d[n]       );
            }       
        }       
        gpg_md_final( md );   
        mdbuf = gpg_md_read( md );
    }
    if( mdbuf && fprint )
        memcpy( fprint, mdbuf, 20 );
    return mdbuf? mdbuf[16] << 24 | mdbuf[17] << 16 | mdbuf[18] << 8 | mdbuf[19] : 0;
}


u32
gpg_keyid_from_sk( PKT_secret_key * sk, byte *fprint )
{
    PKT_public_key pk;
    int npkey = pubkey_get_npkey( sk->pubkey_algo );
    int i;
    
    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 gpg_keyid_from_pk( &pk, fprint );
}


/****************
 * Read the next keyblock from stream A.
 * PENDING_PKT should be initialzed to NULL
 * and not chnaged form the caller.
 * Retunr: 0 = okay, -1 no more blocks or another errorcode.
 */
int
gpg_read_keyblock( gpg_iobuf_t a, PACKET **pending_pkt, gpg_kbnode_t *ret_root )
{
    int rc;
    PACKET *pkt;
    gpg_kbnode_t root = NULL;
    int in_cert;

    if( *pending_pkt ) {
        root = gpg_new_kbnode( *pending_pkt );
        *pending_pkt = NULL;
        in_cert = 1;
    }
    else
        in_cert = 0;
    pkt = malloc( sizeof *pkt );
    gpg_init_packet(pkt);
    while( (rc=gpg_parse_packet(a, pkt)) != -1 ) {
        if( rc ) {  /* ignore errors */
            if( rc != G10ERR_UNKNOWN_PACKET ) {
                printf("read_block: read error: %d\n", rc );
                rc = G10ERR_INV_KEYRING;
                goto ready;
            }
            gpg_free_packet( pkt );
            gpg_init_packet(pkt);
            continue;
        }

        if( !root && pkt->pkttype == PKT_SIGNATURE
                  && pkt->pkt.signature->sig_class == 0x20 ) {
            /* this is a revocation certificate which is handled
             * in a special way */
            root = gpg_new_kbnode( pkt );
            pkt = NULL;
            goto ready;
        }

        /* make a linked list of all packets */
        switch( pkt->pkttype ) {
          case PKT_RING_TRUST:
            /* skip those packets */
            gpg_free_packet( pkt );
            gpg_init_packet(pkt);
            break;

          case PKT_PUBLIC_KEY:
          case PKT_SECRET_KEY:
            if( in_cert ) { /* store this packet */
                *pending_pkt = pkt;
                pkt = NULL;
                goto ready;
            }
            in_cert = 1;
          default:
            if( in_cert ) {
                if( !root )
                    root = gpg_new_kbnode( pkt );
                else
                    gpg_add_kbnode( root, gpg_new_kbnode( pkt ) );
                pkt = malloc( sizeof *pkt );
            }
            gpg_init_packet(pkt);
            break;
        }
    }
  ready:
    if( rc == -1 && root )
        rc = 0;

    if( rc )
        gpg_release_kbnode( root );
    else
        *ret_root = root;
    gpg_free_packet( pkt );
    free( pkt );
    return rc;
}