security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2024-12-22 10:19:57 +01:00
Code Activity
gnupg/g10/build-packet.c
Werner Koch 37d2adfe61 a whole bunch of internal cleanups
1998-06-13 06:59:14 +00:00

808 lines
19 KiB
C
Raw Blame History

/* build-packet.c - assemble packets and write them
* Copyright (C) 1998 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
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "packet.h"
#include "errors.h"
#include "iobuf.h"
#include "mpi.h"
#include "util.h"
#include "cipher.h"
#include "memory.h"
#include "options.h"
static int do_comment( IOBUF out, int ctb, PKT_comment *rem );
static int do_user_id( IOBUF out, int ctb, PKT_user_id *uid );
static int do_public_cert( IOBUF out, int ctb, PKT_public_cert *pk );
static int do_secret_cert( IOBUF out, int ctb, PKT_secret_cert *pk );
static int do_symkey_enc( IOBUF out, int ctb, PKT_symkey_enc *enc );
static int do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc );
static u32 calc_plaintext( PKT_plaintext *pt );
static int do_plaintext( IOBUF out, int ctb, PKT_plaintext *pt );
static int do_encrypted( IOBUF out, int ctb, PKT_encrypted *ed );
static int do_compressed( IOBUF out, int ctb, PKT_compressed *cd );
static int do_signature( IOBUF out, int ctb, PKT_signature *sig );
static int do_onepass_sig( IOBUF out, int ctb, PKT_onepass_sig *ops );
static int calc_header_length( u32 len );
static int write_16(IOBUF inp, u16 a);
static int write_32(IOBUF inp, u32 a);
static int write_header( IOBUF out, int ctb, u32 len );
static int write_header2( IOBUF out, int ctb, u32 len, int hdrlen, int blkmode );
static int write_new_header( IOBUF out, int ctb, u32 len, int hdrlen );
static int write_version( IOBUF out, int ctb );
/****************
* Build a packet and write it to INP
* Returns: 0 := okay
* >0 := error
* Note: Caller must free the packet
*/
int
build_packet( IOBUF out, PACKET *pkt )
{
int rc=0, ctb;
if( DBG_PACKET )
log_debug("build_packet() type=%d\n", pkt->pkttype );
if( pkt->pkttype == PKT_OLD_COMMENT )
pkt->pkttype = PKT_COMMENT;
assert( pkt->pkt.generic );
if( pkt->pkttype > 15 ) /* new format */
ctb = 0xc0 | (pkt->pkttype & 0x3f);
else
ctb = 0x80 | ((pkt->pkttype & 15)<<2);
switch( pkt->pkttype ) {
case PKT_USER_ID:
rc = do_user_id( out, ctb, pkt->pkt.user_id );
break;
case PKT_COMMENT:
rc = do_comment( out, ctb, pkt->pkt.comment );
break;
case PKT_PUBKEY_SUBCERT:
case PKT_PUBLIC_CERT:
rc = do_public_cert( out, ctb, pkt->pkt.public_cert );
break;
case PKT_SECKEY_SUBCERT:
case PKT_SECRET_CERT:
rc = do_secret_cert( out, ctb, pkt->pkt.secret_cert );
break;
case PKT_SYMKEY_ENC:
rc = do_symkey_enc( out, ctb, pkt->pkt.symkey_enc );
break;
case PKT_PUBKEY_ENC:
rc = do_pubkey_enc( out, ctb, pkt->pkt.pubkey_enc );
break;
case PKT_PLAINTEXT:
rc = do_plaintext( out, ctb, pkt->pkt.plaintext );
break;
case PKT_ENCRYPTED:
rc = do_encrypted( out, ctb, pkt->pkt.encrypted );
break;
case PKT_COMPRESSED:
rc = do_compressed( out, ctb, pkt->pkt.compressed );
break;
case PKT_SIGNATURE:
rc = do_signature( out, ctb, pkt->pkt.signature );
break;
case PKT_ONEPASS_SIG:
rc = do_onepass_sig( out, ctb, pkt->pkt.onepass_sig );
break;
case PKT_RING_TRUST:
default:
log_bug("invalid packet type in build_packet()\n");
break;
}
return rc;
}
/****************
* calculate the length of a packet described by PKT
*/
u32
calc_packet_length( PACKET *pkt )
{
u32 n=0;
assert( pkt->pkt.generic );
switch( pkt->pkttype ) {
case PKT_PLAINTEXT:
n = calc_plaintext( pkt->pkt.plaintext );
break;
case PKT_USER_ID:
case PKT_COMMENT:
case PKT_PUBLIC_CERT:
case PKT_SECRET_CERT:
case PKT_SYMKEY_ENC:
case PKT_PUBKEY_ENC:
case PKT_ENCRYPTED:
case PKT_SIGNATURE:
case PKT_ONEPASS_SIG:
case PKT_RING_TRUST:
case PKT_COMPRESSED:
default:
log_bug("invalid packet type in calc_packet_length()");
break;
}
n += calc_header_length(n);
return n;
}
static int
do_comment( IOBUF out, int ctb, PKT_comment *rem )
{
if( !opt.no_comment ) {
write_header(out, ctb, rem->len);
if( iobuf_write( out, rem->data, rem->len ) )
return G10ERR_WRITE_FILE;
}
return 0;
}
static int
do_user_id( IOBUF out, int ctb, PKT_user_id *uid )
{
write_header(out, ctb, uid->len);
if( iobuf_write( out, uid->name, uid->len ) )
return G10ERR_WRITE_FILE;
return 0;
}
static int
do_public_cert( IOBUF out, int ctb, PKT_public_cert *pkc )
{
int rc = 0;
int n, i;
IOBUF a = iobuf_temp();
if( !pkc->version )
iobuf_put( a, 3 );
else
iobuf_put( a, pkc->version );
write_32(a, pkc->timestamp );
if( pkc->version < 4 )
write_16(a, pkc->valid_days );
iobuf_put(a, pkc->pubkey_algo );
n = pubkey_get_npkey( pkc->pubkey_algo );
for(i=0; i < n; i++ )
mpi_write(a, pkc->pkey[i] );
write_header2(out, ctb, iobuf_get_temp_length(a), pkc->hdrbytes, 1 );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
/****************
* Make a hash value from the public key certificate
*/
void
hash_public_cert( MD_HANDLE md, PKT_public_cert *pkc )
{
PACKET pkt;
int rc = 0;
int c;
IOBUF a = iobuf_temp();
#if 0
FILE *fp = fopen("dump.pkc", "a");
int i=0;
fprintf(fp, "\nHashing PKC (v%d):\n", pkc->version);
#endif
/* build the packet */
init_packet(&pkt);
pkt.pkttype = PKT_PUBLIC_CERT;
pkt.pkt.public_cert = pkc;
if( (rc = build_packet( a, &pkt )) )
log_fatal("build public_cert for hashing failed: %s\n", g10_errstr(rc));
while( (c=iobuf_get(a)) != -1 ) {
#if 0
fprintf( fp," %02x", c );
if( (++i == 24) ) {
putc('\n', fp);
i=0;
}
#endif
md_putc( md, c );
}
#if 0
putc('\n', fp);
fclose(fp);
#endif
iobuf_cancel(a);
}
static int
do_secret_cert( IOBUF out, int ctb, PKT_secret_cert *skc )
{
int rc = 0;
int i, nskey, npkey;
IOBUF a = iobuf_temp();
if( !skc->version )
iobuf_put( a, 3 );
else
iobuf_put( a, skc->version );
write_32(a, skc->timestamp );
if( skc->version < 4 )
write_16(a, skc->valid_days );
iobuf_put(a, skc->pubkey_algo );
nskey = pubkey_get_nskey( skc->pubkey_algo );
npkey = pubkey_get_npkey( skc->pubkey_algo );
assert( npkey < nskey );
for(i=0; i < npkey; i++ )
mpi_write(a, skc->skey[i] );
if( skc->is_protected ) {
if( is_RSA(skc->pubkey_algo) && skc->version < 4 ) {
iobuf_put(a, skc->protect.algo );
iobuf_write(a, skc->protect.iv, 8 );
}
else {
iobuf_put(a, 0xff );
iobuf_put(a, skc->protect.algo );
iobuf_put(a, skc->protect.s2k.mode );
iobuf_put(a, skc->protect.s2k.hash_algo );
if( skc->protect.s2k.mode == 1
|| skc->protect.s2k.mode == 4 )
iobuf_write(a, skc->protect.s2k.salt, 8 );
if( skc->protect.s2k.mode == 4 )
write_32(a, skc->protect.s2k.count );
iobuf_write(a, skc->protect.iv, 8 );
}
}
else
iobuf_put(a, 0 );
for( ; i < nskey; i++ )
mpi_write(a, skc->skey[i] );
write_16(a, skc->csum );
write_header2(out, ctb, iobuf_get_temp_length(a), skc->hdrbytes, 1 );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
static int
do_symkey_enc( IOBUF out, int ctb, PKT_symkey_enc *enc )
{
int rc = 0;
IOBUF a = iobuf_temp();
assert( enc->version == 4 );
switch( enc->s2k.mode ) {
case 0: case 1: case 4: break;
default: log_bug("do_symkey_enc: s2k=%d\n", enc->s2k.mode );
}
iobuf_put( a, enc->version );
iobuf_put( a, enc->cipher_algo );
iobuf_put( a, enc->s2k.mode );
iobuf_put( a, enc->s2k.hash_algo );
if( enc->s2k.mode == 1 || enc->s2k.mode == 4 ) {
iobuf_write(a, enc->s2k.salt, 8 );
if( enc->s2k.mode == 4 )
write_32(a, enc->s2k.count);
}
if( enc->seskeylen )
iobuf_write(a, enc->seskey, enc->seskeylen );
write_header(out, ctb, iobuf_get_temp_length(a) );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
static int
do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc )
{
int rc = 0;
int n, i;
IOBUF a = iobuf_temp();
write_version( a, ctb );
write_32(a, enc->keyid[0] );
write_32(a, enc->keyid[1] );
iobuf_put(a,enc->pubkey_algo );
n = pubkey_get_nenc( enc->pubkey_algo );
for(i=0; i < n; i++ )
mpi_write(a, enc->data[i] );
write_header(out, ctb, iobuf_get_temp_length(a) );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
static u32
calc_plaintext( PKT_plaintext *pt )
{
return pt->len? (1 + 1 + pt->namelen + 4 + pt->len) : 0;
}
static int
do_plaintext( IOBUF out, int ctb, PKT_plaintext *pt )
{
int i, rc = 0;
u32 n;
byte buf[1000]; /* FIXME: this buffer has the plaintext! */
int nbytes;
write_header(out, ctb, calc_plaintext( pt ) );
iobuf_put(out, pt->mode );
iobuf_put(out, pt->namelen );
for(i=0; i < pt->namelen; i++ )
iobuf_put(out, pt->name[i] );
if( write_32(out, pt->timestamp ) )
rc = G10ERR_WRITE_FILE;
n = 0;
while( (nbytes=iobuf_read(pt->buf, buf, 1000)) != -1 ) {
if( iobuf_write(out, buf, nbytes) == -1 ) {
rc = G10ERR_WRITE_FILE;
break;
}
n += nbytes;
}
memset(buf,0,1000); /* at least burn the buffer */
if( !pt->len )
iobuf_set_block_mode(out, 0 ); /* write end marker */
else if( n != pt->len )
log_error("do_plaintext(): wrote %lu bytes but expected %lu bytes\n",
(ulong)n, (ulong)pt->len );
return rc;
}
static int
do_encrypted( IOBUF out, int ctb, PKT_encrypted *ed )
{
int rc = 0;
u32 n;
n = ed->len ? (ed->len + 10) : 0;
write_header(out, ctb, n );
/* This is all. The caller has to write the real data */
return rc;
}
static int
do_compressed( IOBUF out, int ctb, PKT_compressed *cd )
{
int rc = 0;
/* we must use the old convention and don't use blockmode */
write_header2(out, ctb, 0, 0, 0 );
iobuf_put(out, cd->algorithm );
/* This is all. The caller has to write the real data */
return rc;
}
/****************
* Find a subpacket of type REQTYPE in BUFFER and a return a pointer
* to the first byte of that subpacket data.
* And return the length of the packet in RET_N and the number of
* header bytes in RET_HLEN (length header and type byte).
*/
byte *
find_subpkt( byte *buffer, sigsubpkttype_t reqtype,
size_t *ret_hlen, size_t *ret_n )
{
int buflen;
sigsubpkttype_t type;
byte *bufstart;
size_t n;
if( !buffer )
return NULL;
buflen = (*buffer << 8) | buffer[1];
buffer += 2;
for(;;) {
if( !buflen )
return NULL; /* end of packets; not found */
bufstart = buffer;
n = *buffer++; buflen--;
if( n == 255 ) {
if( buflen < 4 )
break;
n = (buffer[0] << 24) | (buffer[1] << 16)
| (buffer[2] << 8) | buffer[3];
buffer += 4;
buflen -= 4;
}
else if( n >= 192 ) {
if( buflen < 2 )
break;
n = (( n - 192 ) << 8) + *buffer + 192;
buflen--;
}
if( buflen < n )
break;
type = *buffer & 0x7f;
if( type == reqtype ) {
buffer++;
n--;
if( n > buflen )
break;
if( ret_hlen )
*ret_hlen = buffer - bufstart;
if( ret_n )
*ret_n = n;
return buffer;
}
buffer += n; buflen -=n;
}
log_error("find_subpkt: buffer shorter than subpacket\n");
return NULL;
}
/****************
* Create or update a signature subpacket for SIG of TYPE.
* This functions know, where to put the data (hashed or unhashed).
* The function may move data from the unhased part to the hashed one.
* Note: All pointers into sig->[un]hashed are not valid after a call
* to this function. The data to but into the subpaket should be
* in buffer with a length of buflen.
*/
void
build_sig_subpkt( PKT_signature *sig, sigsubpkttype_t type,
const byte *buffer, size_t buflen )
{
byte *data;
size_t hlen, dlen;
int found, hashed, realloced;
size_t n, n0;
if( (data = find_subpkt( sig->hashed_data, type, &hlen, &dlen )) )
found = 1;
else if( (data = find_subpkt( sig->unhashed_data, type, &hlen, &dlen )))
found = 2;
else
found = 0;
if( found )
log_bug("build_sig_packet: update nyi\n");
if( buflen+1 >= 192 )
log_bug("build_sig_packet: long subpackets are nyi\n");
switch( type ) {
case SIGSUBPKT_SIG_CREATED:
case SIGSUBPKT_PRIV_ADD_SIG:
hashed = 1; break;
default: hashed = 0; break;
}
if( hashed ) {
n0 = sig->hashed_data ? ((*sig->hashed_data << 8)
| sig->hashed_data[1]) : 0;
n = n0 + 1 + 1 + buflen; /* length, type, buffer */
realloced = !!sig->hashed_data;
data = sig->hashed_data ? m_realloc( sig->hashed_data, n+2 )
: m_alloc( n+2 );
}
else {
n0 = sig->unhashed_data ? ((*sig->unhashed_data << 8)
| sig->unhashed_data[1]) : 0;
n = n0 + 1 + 1 + buflen; /* length, type, buffer */
realloced = !!sig->unhashed_data;
data = sig->unhashed_data ? m_realloc( sig->unhashed_data, n+2 )
: m_alloc( n+2 );
}
data[n0+0] = (n >> 8) & 0xff;
data[n0+1] = n & 0xff;
data[n0+2] = buflen+1;
data[n0+3] = type;
memcpy(data+n0+4, buffer, buflen );
if( hashed ) {
if( !realloced )
m_free(sig->hashed_data);
sig->hashed_data = data;
}
else {
if( !realloced )
m_free(sig->unhashed_data);
sig->unhashed_data = data;
}
}
/****************
* Put all the required stuff from SIG into subpackets of sig.
*/
void
build_sig_subpkt_from_sig( PKT_signature *sig )
{
u32 u;
byte buf[8];
u = sig->keyid[0];
buf[0] = (u >> 24) & 0xff;
buf[1] = (u >> 16) & 0xff;
buf[2] = (u >> 8) & 0xff;
buf[3] = u & 0xff;
u = sig->keyid[1];
buf[4] = (u >> 24) & 0xff;
buf[5] = (u >> 16) & 0xff;
buf[6] = (u >> 8) & 0xff;
buf[7] = u & 0xff;
build_sig_subpkt( sig, SIGSUBPKT_ISSUER, buf, 8 );
u = sig->timestamp;
buf[0] = (u >> 24) & 0xff;
buf[1] = (u >> 16) & 0xff;
buf[2] = (u >> 8) & 0xff;
buf[3] = u & 0xff;
build_sig_subpkt( sig, SIGSUBPKT_SIG_CREATED, buf, 4 );
}
static int
do_signature( IOBUF out, int ctb, PKT_signature *sig )
{
int rc = 0;
int n, i;
IOBUF a = iobuf_temp();
if( !sig->version )
iobuf_put( a, 3 );
else
iobuf_put( a, sig->version );
if( sig->version < 4 )
iobuf_put(a, 5 ); /* constant */
iobuf_put(a, sig->sig_class );
if( sig->version < 4 ) {
write_32(a, sig->timestamp );
write_32(a, sig->keyid[0] );
write_32(a, sig->keyid[1] );
}
iobuf_put(a, sig->pubkey_algo );
iobuf_put(a, sig->digest_algo );
if( sig->version >= 4 ) {
size_t n;
/* timestamp and keyid must have been packed into the
* subpackets prior to the call of this function, because
* these subpackets are hashed */
n = sig->hashed_data?((sig->hashed_data[0]<<8)
|sig->hashed_data[1]) :0;
write_16(a, n);
if( n )
iobuf_write( a, sig->hashed_data+2, n );
n = sig->unhashed_data?((sig->unhashed_data[0]<<8)
|sig->unhashed_data[1]) :0;
write_16(a, n);
if( n )
iobuf_write( a, sig->unhashed_data+2, n );
}
iobuf_put(a, sig->digest_start[0] );
iobuf_put(a, sig->digest_start[1] );
n = pubkey_get_nsig( sig->pubkey_algo );
for(i=0; i < n; i++ )
mpi_write(a, sig->data[i] );
write_header(out, ctb, iobuf_get_temp_length(a) );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
static int
do_onepass_sig( IOBUF out, int ctb, PKT_onepass_sig *ops )
{
int rc = 0;
IOBUF a = iobuf_temp();
write_version( a, ctb );
iobuf_put(a, ops->sig_class );
iobuf_put(a, ops->digest_algo );
iobuf_put(a, ops->pubkey_algo );
write_32(a, ops->keyid[0] );
write_32(a, ops->keyid[1] );
iobuf_put(a, ops->last );
write_header(out, ctb, iobuf_get_temp_length(a) );
if( iobuf_write_temp( out, a ) )
rc = G10ERR_WRITE_FILE;
iobuf_close(a);
return rc;
}
static int
write_16(IOBUF out, u16 a)
{
iobuf_put(out, a>>8);
if( iobuf_put(out,a) )
return -1;
return 0;
}
static int
write_32(IOBUF out, u32 a)
{
iobuf_put(out, a>> 24);
iobuf_put(out, a>> 16);
iobuf_put(out, a>> 8);
if( iobuf_put(out, a) )
return -1;
return 0;
}
/****************
* calculate the length of a header
*/
static int
calc_header_length( u32 len )
{
if( !len )
return 1; /* only the ctb */
else if( len < 256 )
return 2;
else if( len < 65536 )
return 3;
else
return 5;
}
/****************
* Write the CTB and the packet length
*/
static int
write_header( IOBUF out, int ctb, u32 len )
{
return write_header2( out, ctb, len, 0, 1 );
}
/****************
* if HDRLEN is > 0, try to build a header of this length.
* we need this, so that we can hash packets without reading them again.
*/
static int
write_header2( IOBUF out, int ctb, u32 len, int hdrlen, int blkmode )
{
if( ctb & 0x40 )
return write_new_header( out, ctb, len, hdrlen );
if( hdrlen ) {
if( !len )
ctb |= 3;
else if( hdrlen == 2 && len < 256 )
;
else if( hdrlen == 3 && len < 65536 )
ctb |= 1;
else
ctb |= 2;
}
else {
if( !len )
ctb |= 3;
else if( len < 256 )
;
else if( len < 65536 )
ctb |= 1;
else
ctb |= 2;
}
if( iobuf_put(out, ctb ) )
return -1;
if( !len ) {
if( blkmode )
iobuf_set_block_mode(out, 8196 );
}
else {
if( ctb & 2 ) {
iobuf_put(out, len >> 24 );
iobuf_put(out, len >> 16 );
}
if( ctb & 3 )
iobuf_put(out, len >> 8 );
if( iobuf_put(out, len ) )
return -1;
}
return 0;
}
static int
write_new_header( IOBUF out, int ctb, u32 len, int hdrlen )
{
if( hdrlen )
log_bug("can't cope with hdrlen yet\n");
if( iobuf_put(out, ctb ) )
return -1;
if( !len ) {
log_bug("can't write partial headers yet\n");
}
else {
if( len < 192 ) {
if( iobuf_put(out, len ) )
return -1;
}
else if( len < 8384 ) {
len -= 192;
if( iobuf_put( out, (len / 256) + 192) )
return -1;
if( iobuf_put( out, (len % 256) ) )
return -1;
}
else {
if( iobuf_put( out, 0xff ) )
return -1;
if( iobuf_put( out, (len >> 24)&0xff ) )
return -1;
if( iobuf_put( out, (len >> 16)&0xff ) )
return -1;
if( iobuf_put( out, (len >> 8)&0xff ) )
return -1;
if( iobuf_put( out, len & 0xff ) )
return -1;
}
}
return 0;
}
static int
write_version( IOBUF out, int ctb )
{
if( iobuf_put( out, 3 ) )
return -1;
return 0;
}
View Git Blame Copy Permalink