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* armor.c (fake_packet, armor_filter): Use the 2440 partial length

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encoding for the faked plaintext packet.
This commit is contained in:
David Shaw 2004-03-04 20:40:12 +00:00
parent c562c9e837
commit 64e3f5a313
2 changed files with 53 additions and 25 deletions
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5
g10/ChangeLog
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@ -1,3 +1,8 @@
2004-03-04 David Shaw <dshaw@jabberwocky.com>
* armor.c (fake_packet, armor_filter): Use the 2440 partial length
encoding for the faked plaintext packet.
2004-03-03 David Shaw <dshaw@jabberwocky.com> 2004-03-03 David Shaw <dshaw@jabberwocky.com>
* options.h, g10.c (main), mainproc.c (check_sig_and_print): * options.h, g10.c (main), mainproc.c (check_sig_and_print):

69
g10/armor.c
View File

@ -1,6 +1,6 @@
/* armor.c - Armor flter /* armor.c - Armor flter
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
* Free Software Foundation, Inc. * 2004 Free Software Foundation, Inc.
* *
* This file is part of GnuPG. * This file is part of GnuPG.
* *
@ -464,7 +464,8 @@ check_input( armor_filter_context_t *afx, IOBUF a )
return rc; return rc;
} }
#define PARTIAL_CHUNK 512
#define PARTIAL_POW 9
/**************** /****************
* Fake a literal data packet and wait for the next armor line * Fake a literal data packet and wait for the next armor line
@ -480,17 +481,29 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
int lastline = 0; int lastline = 0;
unsigned maxlen, n; unsigned maxlen, n;
byte *p; byte *p;
byte tempbuf[PARTIAL_CHUNK];
size_t tempbuf_len=0;
len = 2; /* reserve 2 bytes for the length header */ while( !rc && size-len>=(PARTIAL_CHUNK+1)) {
size -= 2; /* and 2 for the terminating header */
while( !rc && len < size ) {
/* copy what we have in the line buffer */ /* copy what we have in the line buffer */
if( afx->faked == 1 ) if( afx->faked == 1 )
afx->faked++; /* skip the first (empty) line */ afx->faked++; /* skip the first (empty) line */
else { else
while( len < size && afx->buffer_pos < afx->buffer_len ) {
buf[len++] = afx->buffer[afx->buffer_pos++]; /* It's full, so write this partial chunk */
if( len >= size ) if(tempbuf_len==PARTIAL_CHUNK)
{
buf[len++]=0xE0+PARTIAL_POW;
memcpy(&buf[len],tempbuf,PARTIAL_CHUNK);
len+=PARTIAL_CHUNK;
tempbuf_len=0;
continue;
}
while( tempbuf_len < PARTIAL_CHUNK
&& afx->buffer_pos < afx->buffer_len )
tempbuf[tempbuf_len++] = afx->buffer[afx->buffer_pos++];
if( tempbuf_len==PARTIAL_CHUNK )
continue; continue;
} }
@ -560,13 +573,17 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
} }
} }
buf[0] = (len-2) >> 8;
buf[1] = (len-2);
if( lastline ) { /* write last (ending) length header */ if( lastline ) { /* write last (ending) length header */
if( buf[0] || buf[1] ) { /* only if we have some text */ if(tempbuf_len<192)
buf[len++] = 0; buf[len++]=tempbuf_len;
buf[len++] = 0; else
{
buf[len++]=((tempbuf_len-192)/256) + 192;
buf[len++]=(tempbuf_len-192) % 256;
} }
memcpy(&buf[len],tempbuf,tempbuf_len);
len+=tempbuf_len;
rc = 0; rc = 0;
afx->faked = 0; afx->faked = 0;
afx->in_cleartext = 0; afx->in_cleartext = 0;
@ -842,9 +859,10 @@ armor_filter( void *opaque, int control,
*ret_len = n; *ret_len = n;
} }
else if( control == IOBUFCTRL_UNDERFLOW ) { else if( control == IOBUFCTRL_UNDERFLOW ) {
/* We need some space for the faked packet. The minmum required /* We need some space for the faked packet. The minmum
* size is ~18 + length of the session marker */ * required size is the PARTIAL_CHUNK size plus a byte for the
if( size < 50 ) * length itself */
if( size < PARTIAL_CHUNK+1 )
BUG(); /* supplied buffer too short */ BUG(); /* supplied buffer too short */
if( afx->faked ) if( afx->faked )
@ -901,12 +919,17 @@ armor_filter( void *opaque, int control,
buf[n++] = DIGEST_ALGO_SHA512; buf[n++] = DIGEST_ALGO_SHA512;
buf[1] = n - 2; buf[1] = n - 2;
/* followed by a plaintext packet */ /* followed by an invented plaintext packet.
buf[n++] = 0xaf; /* old packet format, type 11, var length */ Amusingly enough, this packet is not compliant with
buf[n++] = 0; /* set the length header */ 2440 as the initial partial length is less than 512
buf[n++] = 6; bytes. Of course, we'll accept it anyway ;) */
buf[n++] = 0xCB; /* new packet format, type 11 */
buf[n++] = 0xE3; /* 2^3 */
buf[n++] = 't'; /* canonical text mode */ buf[n++] = 't'; /* canonical text mode */
buf[n++] = 0; /* namelength */ buf[n++] = 2; /* namelength */
buf[n++] = 'i'; /* padding to get us to 2^3 bytes */
buf[n++] = 's'; /* this comment intentionally left blank */
memset(buf+n, 0, 4); /* timestamp */ memset(buf+n, 0, 4); /* timestamp */
n += 4; n += 4;
} }