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gnupg/g10/verify.c

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/* verify.c - Verify signed data
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006,
* 2007, 2010 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 "options.h"
#include "packet.h"
#include "../common/status.h"
#include "../common/iobuf.h"
#include "keydb.h"
#include "../common/util.h"
#include "main.h"
#include "filter.h"
#include "../common/ttyio.h"
#include "../common/i18n.h"
/****************
* Assume that the input is a signature and verify it without
* generating any output. With no arguments, the signature packet
* is read from stdin (it may be a detached signature when not
* used in batch mode). If only a sigfile is given, it may be a complete
* signature or a detached signature in which case the signed stuff
* is expected from stdin. With more than 1 argument, the first should
* be a detached signature and the remaining files are the signed stuff.
*/
int
verify_signatures (ctrl_t ctrl, int nfiles, char **files )
{
IOBUF fp;
armor_filter_context_t *afx = NULL;
progress_filter_context_t *pfx = new_progress_context ();
const char *sigfile;
int i, rc;
strlist_t sl;
/* Decide whether we should handle a detached or a normal signature,
* which is needed so that the code later can hash the correct data and
* not have a normal signature act as detached signature and ignoring the
* intended signed material from the 2nd file or stdin.
* 1. gpg <file - normal
* 2. gpg file - normal (or detached)
* 3. gpg file <file2 - detached
* 4. gpg file file2 - detached
* The question is how decide between case 2 and 3? The only way
* we can do it is by reading one byte from stdin and then unget
* it; the problem here is that we may be reading from the
* terminal (which could be detected using isatty() but won't work
* when under contol of a pty using program (e.g. expect)) and
* might get us in trouble when stdin is used for another purpose
* (--passphrase-fd 0). So we have to break with the behaviour
* prior to gpg 1.0.4 by assuming that case 3 is a normal
* signature (where file2 is ignored and require for a detached
* signature to indicate signed material comes from stdin by using
* case 4 with a file2 of "-".
*
* Actually we don't have to change anything here but can handle
* that all quite easily in mainproc.c
*/
sigfile = nfiles? *files : NULL;
/* open the signature file */
fp = iobuf_open(sigfile);
if (fp && is_secured_file (iobuf_get_fd (fp)))
{
iobuf_close (fp);
fp = NULL;
gpg_err_set_errno (EPERM);
}
if( !fp ) {
rc = gpg_error_from_syserror ();
log_error(_("can't open '%s': %s\n"),
print_fname_stdin(sigfile), gpg_strerror (rc));
goto leave;
}
handle_progress (pfx, fp, sigfile);
if ( !opt.no_armor && use_armor_filter( fp ) )
{
afx = new_armor_context ();
push_armor_filter (afx, fp);
}
sl = NULL;
for(i=nfiles-1 ; i > 0 ; i-- )
add_to_strlist( &sl, files[i] );
rc = proc_signature_packets (ctrl, NULL, fp, sl, sigfile );
free_strlist(sl);
iobuf_close(fp);
if( (afx && afx->no_openpgp_data && rc == -1)
|| gpg_err_code (rc) == GPG_ERR_NO_DATA ) {
log_error(_("the signature could not be verified.\n"
"Please remember that the signature file (.sig or .asc)\n"
"should be the first file given on the command line.\n") );
rc = 0;
}
leave:
release_armor_context (afx);
release_progress_context (pfx);
return rc;
}
void
print_file_status( int status, const char *name, int what )
{
char *p = xmalloc(strlen(name)+10);
sprintf(p, "%d %s", what, name );
write_status_text( status, p );
xfree(p);
}
static int
verify_one_file (ctrl_t ctrl, const char *name )
{
IOBUF fp;
armor_filter_context_t *afx = NULL;
progress_filter_context_t *pfx = new_progress_context ();
int rc;
print_file_status( STATUS_FILE_START, name, 1 );
fp = iobuf_open(name);
if (fp)
iobuf_ioctl (fp, IOBUF_IOCTL_NO_CACHE, 1, NULL);
if (fp && is_secured_file (iobuf_get_fd (fp)))
{
iobuf_close (fp);
fp = NULL;
gpg_err_set_errno (EPERM);
}
if( !fp ) {
rc = gpg_error_from_syserror ();
log_error(_("can't open '%s': %s\n"),
print_fname_stdin(name), strerror (errno));
print_file_status( STATUS_FILE_ERROR, name, 1 );
goto leave;
}
handle_progress (pfx, fp, name);
if( !opt.no_armor ) {
if( use_armor_filter( fp ) ) {
afx = new_armor_context ();
push_armor_filter (afx, fp);
}
}
rc = proc_signature_packets (ctrl, NULL, fp, NULL, name );
iobuf_close(fp);
write_status( STATUS_FILE_DONE );
reset_literals_seen();
leave:
release_armor_context (afx);
release_progress_context (pfx);
return rc;
}
/****************
* Verify each file given in the files array or read the names of the
* files from stdin.
* Note: This function can not handle detached signatures.
*/
int
verify_files (ctrl_t ctrl, int nfiles, char **files )
{
int i, rc;
int first_rc = 0;
if( !nfiles ) { /* read the filenames from stdin */
char line[2048];
unsigned int lno = 0;
while( fgets(line, DIM(line), stdin) ) {
lno++;
if( !*line || line[strlen(line)-1] != '\n' ) {
log_error(_("input line %u too long or missing LF\n"), lno );
return GPG_ERR_GENERAL;
}
/* This code does not work on MSDOS but hwo cares there are
* also no script languages available. We don't strip any
* spaces, so that we can process nearly all filenames */
line[strlen(line)-1] = 0;
rc = verify_one_file (ctrl, line);
if (!first_rc)
first_rc = rc;
}
}
else { /* take filenames from the array */
for(i=0; i < nfiles; i++ )
{
rc = verify_one_file (ctrl, files[i]);
if (!first_rc)
first_rc = rc;
}
}
return first_rc;
}
/* Perform a verify operation. To verify detached signatures, DATA_FD
shall be the descriptor of the signed data; for regular signatures
it needs to be -1. If OUT_FP is not NULL and DATA_FD is not -1 the
the signed material gets written that stream.
FIXME: OUTFP is not yet implemented.
*/
int
gpg_verify (ctrl_t ctrl, int sig_fd, int data_fd, estream_t out_fp)
{
int rc;
iobuf_t fp;
armor_filter_context_t *afx = NULL;
progress_filter_context_t *pfx = new_progress_context ();
(void)ctrl;
(void)out_fp;
if (is_secured_file (sig_fd))
{
fp = NULL;
gpg_err_set_errno (EPERM);
}
else
fp = iobuf_fdopen_nc (sig_fd, "rb");
if (!fp)
{
rc = gpg_error_from_syserror ();
log_error (_("can't open fd %d: %s\n"), sig_fd, strerror (errno));
goto leave;
}
handle_progress (pfx, fp, NULL);
if ( !opt.no_armor && use_armor_filter (fp) )
{
afx = new_armor_context ();
push_armor_filter (afx, fp);
}
rc = proc_signature_packets_by_fd (ctrl, NULL, fp, data_fd);
if ( afx && afx->no_openpgp_data
&& (rc == -1 || gpg_err_code (rc) == GPG_ERR_EOF) )
rc = gpg_error (GPG_ERR_NO_DATA);
leave:
iobuf_close (fp);
release_progress_context (pfx);
release_armor_context (afx);
return rc;
}
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