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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>
* options.h, g10.c (main), mainproc.c (check_sig_and_print):

73
g10/armor.c
View File

@ -1,6 +1,6 @@
/* armor.c - Armor flter
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
* Free Software Foundation, Inc.
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
* 2004 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
@ -464,7 +464,8 @@ check_input( armor_filter_context_t *afx, IOBUF a )
return rc;
}
#define PARTIAL_CHUNK 512
#define PARTIAL_POW 9
/****************
* Fake a literal data packet and wait for the next armor line
@ -480,19 +481,31 @@ fake_packet( armor_filter_context_t *afx, IOBUF a,
int lastline = 0;
unsigned maxlen, n;
byte *p;
byte tempbuf[PARTIAL_CHUNK];
size_t tempbuf_len=0;
len = 2; /* reserve 2 bytes for the length header */
size -= 2; /* and 2 for the terminating header */
while( !rc && len < size ) {
while( !rc && size-len>=(PARTIAL_CHUNK+1)) {
/* copy what we have in the line buffer */
if( afx->faked == 1 )
afx->faked++; /* skip the first (empty) line */
else {
while( len < size && afx->buffer_pos < afx->buffer_len )
buf[len++] = afx->buffer[afx->buffer_pos++];
if( len >= size )
else
{
/* It's full, so write this partial chunk */
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;
}
/* read the next line */
maxlen = MAX_LINELEN;
@ -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( buf[0] || buf[1] ) { /* only if we have some text */
buf[len++] = 0;
buf[len++] = 0;
}
if(tempbuf_len<192)
buf[len++]=tempbuf_len;
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;
afx->faked = 0;
afx->in_cleartext = 0;
@ -842,9 +859,10 @@ armor_filter( void *opaque, int control,
*ret_len = n;
}
else if( control == IOBUFCTRL_UNDERFLOW ) {
/* We need some space for the faked packet. The minmum required
* size is ~18 + length of the session marker */
if( size < 50 )
/* We need some space for the faked packet. The minmum
* required size is the PARTIAL_CHUNK size plus a byte for the
* length itself */
if( size < PARTIAL_CHUNK+1 )
BUG(); /* supplied buffer too short */
if( afx->faked )
@ -901,12 +919,17 @@ armor_filter( void *opaque, int control,
buf[n++] = DIGEST_ALGO_SHA512;
buf[1] = n - 2;
/* followed by a plaintext packet */
buf[n++] = 0xaf; /* old packet format, type 11, var length */
buf[n++] = 0; /* set the length header */
buf[n++] = 6;
/* followed by an invented plaintext packet.
Amusingly enough, this packet is not compliant with
2440 as the initial partial length is less than 512
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++] = 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 */
n += 4;
}