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/* textfilter.c
* Copyright (C) 1998, 1999, 2000, 2001, 2004 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "gpg.h"
#include "../common/status.h"
#include "../common/iobuf.h"
#include "../common/util.h"
#include "filter.h"
#include "../common/i18n.h"
#include "options.h"
#include "../common/status.h"
#ifdef HAVE_DOSISH_SYSTEM
#define LF "\r\n"
#else
#define LF "\n"
#endif
#define MAX_LINELEN 19995 /* a little bit smaller than in armor.c */
/* to make sure that a warning is displayed while */
/* creating a message */
static unsigned
len_without_trailing_chars( byte *line, unsigned len, const char *trimchars )
{
byte *p, *mark;
unsigned n;
for(mark=NULL, p=line, n=0; n < len; n++, p++ ) {
if( strchr( trimchars, *p ) ) {
if( !mark )
mark = p;
}
else
mark = NULL;
}
return mark? (mark - line) : len;
}
static int
standard( text_filter_context_t *tfx, IOBUF a,
byte *buf, size_t size, size_t *ret_len)
{
int rc=0;
size_t len = 0;
unsigned maxlen;
log_assert( size > 10 );
size -= 2; /* reserve 2 bytes to append CR,LF */
while( !rc && len < size ) {
int lf_seen;
while( len < size && tfx->buffer_pos < tfx->buffer_len )
buf[len++] = tfx->buffer[tfx->buffer_pos++];
if( len >= size )
continue;
/* read the next line */
maxlen = MAX_LINELEN;
tfx->buffer_pos = 0;
tfx->buffer_len = iobuf_read_line( a, &tfx->buffer,
&tfx->buffer_size, &maxlen );
if( !maxlen )
tfx->truncated++;
if( !tfx->buffer_len ) {
if( !len )
rc = -1; /* eof */
break;
}
lf_seen = tfx->buffer[tfx->buffer_len-1] == '\n';
/* The story behind this is that 2440 says that textmode
hashes should canonicalize line endings to CRLF and remove
spaces and tabs. 2440bis-12 says to just canonicalize to
CRLF. 1.4.0 was released using the bis-12 behavior, but it
was discovered that many mail clients do not canonicalize
PGP/MIME signature text appropriately (and were relying on
GnuPG to handle trailing spaces). So, we default to the
2440 behavior, but use the 2440bis-12 behavior if the user
specifies --no-rfc2440-text. The default will be changed
at some point in the future when the mail clients have been
upgraded. Aside from PGP/MIME and broken mail clients,
this makes no difference to any signatures in the real
world except for a textmode detached signature. PGP always
used the 2440bis-12 behavior (ignoring 2440 itself), so
this actually makes us compatible with PGP textmode
detached signatures for the first time. */
if(opt.rfc2440_text)
tfx->buffer_len=trim_trailing_chars(tfx->buffer,tfx->buffer_len,
" \t\r\n");
else
tfx->buffer_len=trim_trailing_chars(tfx->buffer,tfx->buffer_len,
"\r\n");
if( lf_seen ) {
tfx->buffer[tfx->buffer_len++] = '\r';
tfx->buffer[tfx->buffer_len++] = '\n';
}
}
*ret_len = len;
return rc;
}
/****************
* The filter is used to make canonical text: Lines are terminated by
* CR, LF, trailing white spaces are removed.
*/
int
text_filter( void *opaque, int control,
IOBUF a, byte *buf, size_t *ret_len)
{
size_t size = *ret_len;
text_filter_context_t *tfx = opaque;
int rc=0;
if( control == IOBUFCTRL_UNDERFLOW ) {
rc = standard( tfx, a, buf, size, ret_len );
}
else if( control == IOBUFCTRL_FREE ) {
if( tfx->truncated )
log_error(_("can't handle text lines longer than %d characters\n"),
MAX_LINELEN );
xfree( tfx->buffer );
tfx->buffer = NULL;
}
else if( control == IOBUFCTRL_DESC )
mem2str (buf, "text_filter", *ret_len);
return rc;
}
/****************
* Copy data from INP to OUT and do some escaping if requested.
* md is updated as required by rfc2440
*/
int
copy_clearsig_text( IOBUF out, IOBUF inp, gcry_md_hd_t md,
int escape_dash, int escape_from)
{
unsigned int maxlen;
byte *buffer = NULL; /* malloced buffer */
unsigned int bufsize; /* and size of this buffer */
unsigned int n;
int truncated = 0;
int pending_lf = 0;
if( !escape_dash )
escape_from = 0;
write_status_begin_signing (md);
for(;;) {
maxlen = MAX_LINELEN;
n = iobuf_read_line( inp, &buffer, &bufsize, &maxlen );
if( !maxlen )
truncated++;
if( !n )
break; /* read_line has returned eof */
/* update the message digest */
if( escape_dash ) {
if( pending_lf ) {
gcry_md_putc ( md, '\r' );
gcry_md_putc ( md, '\n' );
}
gcry_md_write ( md, buffer,
len_without_trailing_chars (buffer, n, " \t\r\n"));
}
else
gcry_md_write ( md, buffer, n );
pending_lf = buffer[n-1] == '\n';
/* write the output */
if( ( escape_dash && *buffer == '-')
|| ( escape_from && n > 4 && !memcmp(buffer, "From ", 5 ) ) ) {
iobuf_put( out, '-' );
iobuf_put( out, ' ' );
}
#if 0 /*defined(HAVE_DOSISH_SYSTEM)*/
/* We don't use this anymore because my interpretation of rfc2440 7.1
* is that there is no conversion needed. If one decides to
* clearsign a unix file on a DOS box he will get a mixed line endings.
* If at some point it turns out, that a conversion is a nice feature
* we can make an option out of it.
*/
/* make sure the lines do end in CR,LF */
if( n > 1 && ( (buffer[n-2] == '\r' && buffer[n-1] == '\n' )
|| (buffer[n-2] == '\n' && buffer[n-1] == '\r'))) {
iobuf_write( out, buffer, n-2 );
iobuf_put( out, '\r');
iobuf_put( out, '\n');
}
else if( n && buffer[n-1] == '\n' ) {
iobuf_write( out, buffer, n-1 );
iobuf_put( out, '\r');
iobuf_put( out, '\n');
}
else
iobuf_write( out, buffer, n );
#else
iobuf_write( out, buffer, n );
#endif
}
/* at eof */
if( !pending_lf ) { /* make sure that the file ends with a LF */
iobuf_writestr( out, LF );
if( !escape_dash )
gcry_md_putc( md, '\n' );
}
if( truncated )
log_info(_("input line longer than %d characters\n"), MAX_LINELEN );
xfree (buffer);
return 0; /* okay */
}

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Mime Type
text/x-c
Expires
Mon, Dec 23, 4:13 PM (14 h, 29 m)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
f7/da/6b38ed0b496d0e8c6a355dddd49c

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