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![Werner Koch](/assets/img/avatar_default.png)
* g10/verify.c (verify_files): Track the first error code. -- It seems to be possible to play tricks with packet structures so that log_error is not used for a bad input data. By actually checking the return code and let the main driver in gpg call log_error, we can fix this case. Note that using gpg --verify-files and relying solely on gpg's return code is at best a questionable strategy. It is for example impossible to tell which data has been signed. Signed-off-by: Werner Koch <wk@gnupg.org>
284 lines
8.0 KiB
C
284 lines
8.0 KiB
C
/* verify.c - Verify signed data
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* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006,
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* 2007, 2010 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "gpg.h"
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#include "options.h"
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#include "packet.h"
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#include "../common/status.h"
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#include "../common/iobuf.h"
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#include "keydb.h"
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#include "../common/util.h"
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#include "main.h"
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#include "filter.h"
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#include "../common/ttyio.h"
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#include "../common/i18n.h"
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/****************
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* Assume that the input is a signature and verify it without
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* generating any output. With no arguments, the signature packet
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* is read from stdin (it may be a detached signature when not
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* used in batch mode). If only a sigfile is given, it may be a complete
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* signature or a detached signature in which case the signed stuff
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* is expected from stdin. With more than 1 argument, the first should
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* be a detached signature and the remaining files are the signed stuff.
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*/
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int
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verify_signatures (ctrl_t ctrl, int nfiles, char **files )
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{
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IOBUF fp;
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armor_filter_context_t *afx = NULL;
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progress_filter_context_t *pfx = new_progress_context ();
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const char *sigfile;
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int i, rc;
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strlist_t sl;
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/* Decide whether we should handle a detached or a normal signature,
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* which is needed so that the code later can hash the correct data and
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* not have a normal signature act as detached signature and ignoring the
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* intended signed material from the 2nd file or stdin.
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* 1. gpg <file - normal
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* 2. gpg file - normal (or detached)
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* 3. gpg file <file2 - detached
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* 4. gpg file file2 - detached
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* The question is how decide between case 2 and 3? The only way
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* we can do it is by reading one byte from stdin and then unget
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* it; the problem here is that we may be reading from the
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* terminal (which could be detected using isatty() but won't work
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* when under control of a pty using program (e.g. expect)) and
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* might get us in trouble when stdin is used for another purpose
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* (--passphrase-fd 0). So we have to break with the behaviour
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* prior to gpg 1.0.4 by assuming that case 3 is a normal
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* signature (where file2 is ignored and require for a detached
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* signature to indicate signed material comes from stdin by using
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* case 4 with a file2 of "-".
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*
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* Actually we don't have to change anything here but can handle
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* that all quite easily in mainproc.c
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*/
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sigfile = nfiles? *files : NULL;
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/* open the signature file */
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fp = iobuf_open(sigfile);
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if (fp && is_secured_file (iobuf_get_fd (fp)))
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{
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iobuf_close (fp);
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fp = NULL;
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gpg_err_set_errno (EPERM);
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}
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if( !fp ) {
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rc = gpg_error_from_syserror ();
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log_error(_("can't open '%s': %s\n"),
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print_fname_stdin(sigfile), gpg_strerror (rc));
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goto leave;
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}
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handle_progress (pfx, fp, sigfile);
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if ( !opt.no_armor && use_armor_filter( fp ) )
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{
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afx = new_armor_context ();
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push_armor_filter (afx, fp);
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}
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sl = NULL;
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for(i=nfiles-1 ; i > 0 ; i-- )
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add_to_strlist( &sl, files[i] );
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rc = proc_signature_packets (ctrl, NULL, fp, sl, sigfile );
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free_strlist(sl);
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iobuf_close(fp);
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if( (afx && afx->no_openpgp_data && rc == -1)
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|| gpg_err_code (rc) == GPG_ERR_NO_DATA ) {
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log_error(_("the signature could not be verified.\n"
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"Please remember that the signature file (.sig or .asc)\n"
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"should be the first file given on the command line.\n") );
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rc = 0;
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}
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leave:
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release_armor_context (afx);
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release_progress_context (pfx);
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return rc;
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}
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void
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print_file_status( int status, const char *name, int what )
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{
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char *p = xmalloc(strlen(name)+10);
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sprintf(p, "%d %s", what, name );
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write_status_text( status, p );
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xfree(p);
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}
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static int
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verify_one_file (ctrl_t ctrl, const char *name )
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{
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IOBUF fp;
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armor_filter_context_t *afx = NULL;
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progress_filter_context_t *pfx = new_progress_context ();
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int rc;
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print_file_status( STATUS_FILE_START, name, 1 );
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fp = iobuf_open(name);
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if (fp)
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iobuf_ioctl (fp, IOBUF_IOCTL_NO_CACHE, 1, NULL);
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if (fp && is_secured_file (iobuf_get_fd (fp)))
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{
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iobuf_close (fp);
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fp = NULL;
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gpg_err_set_errno (EPERM);
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}
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if( !fp ) {
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rc = gpg_error_from_syserror ();
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log_error(_("can't open '%s': %s\n"),
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print_fname_stdin(name), strerror (errno));
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print_file_status( STATUS_FILE_ERROR, name, 1 );
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goto leave;
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}
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handle_progress (pfx, fp, name);
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if( !opt.no_armor ) {
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if( use_armor_filter( fp ) ) {
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afx = new_armor_context ();
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push_armor_filter (afx, fp);
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}
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}
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rc = proc_signature_packets (ctrl, NULL, fp, NULL, name );
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iobuf_close(fp);
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write_status( STATUS_FILE_DONE );
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reset_literals_seen();
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leave:
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release_armor_context (afx);
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release_progress_context (pfx);
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return rc;
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}
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/****************
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* Verify each file given in the files array or read the names of the
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* files from stdin.
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* Note: This function can not handle detached signatures.
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*/
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int
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verify_files (ctrl_t ctrl, int nfiles, char **files )
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{
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int i, rc;
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int first_rc = 0;
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if( !nfiles ) { /* read the filenames from stdin */
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char line[2048];
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unsigned int lno = 0;
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while( fgets(line, DIM(line), stdin) ) {
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lno++;
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if( !*line || line[strlen(line)-1] != '\n' ) {
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log_error(_("input line %u too long or missing LF\n"), lno );
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return GPG_ERR_GENERAL;
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}
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/* This code does not work on MSDOS but hwo cares there are
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* also no script languages available. We don't strip any
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* spaces, so that we can process nearly all filenames */
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line[strlen(line)-1] = 0;
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rc = verify_one_file (ctrl, line);
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if (!first_rc)
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first_rc = rc;
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}
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}
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else { /* take filenames from the array */
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for(i=0; i < nfiles; i++ )
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{
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rc = verify_one_file (ctrl, files[i]);
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if (!first_rc)
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first_rc = rc;
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}
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}
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return first_rc;
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}
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/* Perform a verify operation. To verify detached signatures, DATA_FD
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shall be the descriptor of the signed data; for regular signatures
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it needs to be -1. If OUT_FP is not NULL and DATA_FD is not -1 the
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the signed material gets written that stream.
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FIXME: OUTFP is not yet implemented.
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*/
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int
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gpg_verify (ctrl_t ctrl, int sig_fd, int data_fd, estream_t out_fp)
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{
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int rc;
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iobuf_t fp;
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armor_filter_context_t *afx = NULL;
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progress_filter_context_t *pfx = new_progress_context ();
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(void)ctrl;
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(void)out_fp;
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if (is_secured_file (sig_fd))
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{
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fp = NULL;
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gpg_err_set_errno (EPERM);
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}
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else
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fp = iobuf_fdopen_nc (sig_fd, "rb");
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if (!fp)
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{
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rc = gpg_error_from_syserror ();
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log_error (_("can't open fd %d: %s\n"), sig_fd, strerror (errno));
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goto leave;
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}
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handle_progress (pfx, fp, NULL);
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if ( !opt.no_armor && use_armor_filter (fp) )
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{
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afx = new_armor_context ();
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push_armor_filter (afx, fp);
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}
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rc = proc_signature_packets_by_fd (ctrl, NULL, fp, data_fd);
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if ( afx && afx->no_openpgp_data
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&& (rc == -1 || gpg_err_code (rc) == GPG_ERR_EOF) )
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rc = gpg_error (GPG_ERR_NO_DATA);
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leave:
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iobuf_close (fp);
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release_progress_context (pfx);
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release_armor_context (afx);
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return rc;
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}
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