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gnupg/g10/gpgv.c
NIIBE Yutaka b531f2fd75 gpgv: Tweak default options for extra security.
* g10/gpgv.c (main): Set opt.no_sig _cache, so that it doesn't depend on
cached status.  Similarly, set opt.flags.require_cross_cert for backsig
validation for subkey signature.

--

(backport of master
commit e32c575e0f)

It is common that an organization distributes binary keyrings with
signature cache (Tag 12, Trust Packet) and people use gpgv to validate
signature with such keyrings.  In such a use case, it is possible that
the key validation itself is skipped.

For the purpose of gpgv validation of signatures, we should not depend
on signature cache in keyrings (if any), but we should validate the key
by its self signature for primary key, and back signature for subkey.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
2016-07-09 10:38:25 +09:00

549 lines
10 KiB
C

/* gpgv.c - The GnuPG signature verify utility
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2006,
* 2008, 2009, 2012 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 <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#ifdef HAVE_DOSISH_SYSTEM
#include <fcntl.h> /* for setmode() */
#endif
#ifdef HAVE_LIBREADLINE
#define GNUPG_LIBREADLINE_H_INCLUDED
#include <readline/readline.h>
#endif
#define INCLUDED_BY_MAIN_MODULE 1
#include "gpg.h"
#include "packet.h"
#include "iobuf.h"
#include "util.h"
#include "main.h"
#include "options.h"
#include "keydb.h"
#include "trustdb.h"
#include "cipher.h"
#include "filter.h"
#include "ttyio.h"
#include "i18n.h"
#include "sysutils.h"
#include "status.h"
#include "call-agent.h"
enum cmd_and_opt_values {
aNull = 0,
oQuiet = 'q',
oVerbose = 'v',
oBatch = 500,
oKeyring,
oIgnoreTimeConflict,
oStatusFD,
oLoggerFD,
oHomedir,
aTest
};
static ARGPARSE_OPTS opts[] = {
ARGPARSE_group (300, N_("@\nOptions:\n ")),
ARGPARSE_s_n (oVerbose, "verbose", N_("verbose")),
ARGPARSE_s_n (oQuiet, "quiet", N_("be somewhat more quiet")),
ARGPARSE_s_s (oKeyring, "keyring",
N_("|FILE|take the keys from the keyring FILE")),
ARGPARSE_s_n (oIgnoreTimeConflict, "ignore-time-conflict",
N_("make timestamp conflicts only a warning")),
ARGPARSE_s_i (oStatusFD, "status-fd",
N_("|FD|write status info to this FD")),
ARGPARSE_s_i (oLoggerFD, "logger-fd", "@"),
ARGPARSE_s_s (oHomedir, "homedir", "@"),
ARGPARSE_end ()
};
int g10_errors_seen = 0;
static char *
make_libversion (const char *libname, const char *(*getfnc)(const char*))
{
const char *s;
char *result;
s = getfnc (NULL);
result = xmalloc (strlen (libname) + 1 + strlen (s) + 1);
strcpy (stpcpy (stpcpy (result, libname), " "), s);
return result;
}
static const char *
my_strusage( int level )
{
static char *ver_gcry;
const char *p;
switch (level)
{
case 11: p = "gpgv (GnuPG)";
break;
case 13: p = VERSION; break;
case 17: p = PRINTABLE_OS_NAME; break;
case 19: p = _("Please report bugs to <@EMAIL@>.\n"); break;
case 1:
case 40: p = _("Usage: gpgv [options] [files] (-h for help)");
break;
case 41: p = _("Syntax: gpgv [options] [files]\n"
"Check signatures against known trusted keys\n");
break;
case 20:
if (!ver_gcry)
ver_gcry = make_libversion ("libgcrypt", gcry_check_version);
p = ver_gcry;
break;
default: p = NULL;
}
return p;
}
int
main( int argc, char **argv )
{
ARGPARSE_ARGS pargs;
int rc=0;
strlist_t sl;
strlist_t nrings=NULL;
unsigned configlineno;
set_strusage (my_strusage);
log_set_prefix ("gpgv", 1);
/* Make sure that our subsystems are ready. */
i18n_init();
init_common_subsystems ();
if (!gcry_check_version (NEED_LIBGCRYPT_VERSION) )
{
log_fatal ( _("%s is too old (need %s, have %s)\n"), "libgcrypt",
NEED_LIBGCRYPT_VERSION, gcry_check_version (NULL) );
}
gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
gnupg_init_signals (0, NULL);
opt.command_fd = -1; /* no command fd */
opt.pgp2_workarounds = 1;
opt.keyserver_options.options|=KEYSERVER_AUTO_KEY_RETRIEVE;
opt.trust_model = TM_ALWAYS;
opt.no_sig_cache = 1;
opt.flags.require_cross_cert = 1;
opt.batch = 1;
opt.homedir = default_homedir ();
tty_no_terminal(1);
tty_batchmode(1);
disable_dotlock();
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
pargs.argc = &argc;
pargs.argv = &argv;
pargs.flags= 1; /* do not remove the args */
while (optfile_parse( NULL, NULL, &configlineno, &pargs, opts))
{
switch (pargs.r_opt)
{
case oQuiet: opt.quiet = 1; break;
case oVerbose:
opt.verbose++;
opt.list_sigs=1;
gcry_control (GCRYCTL_SET_VERBOSITY, (int)opt.verbose);
break;
case oKeyring: append_to_strlist( &nrings, pargs.r.ret_str); break;
case oStatusFD: set_status_fd( pargs.r.ret_int ); break;
case oLoggerFD:
log_set_fd (translate_sys2libc_fd_int (pargs.r.ret_int, 1));
break;
case oHomedir: opt.homedir = pargs.r.ret_str; break;
case oIgnoreTimeConflict: opt.ignore_time_conflict = 1; break;
default : pargs.err = ARGPARSE_PRINT_ERROR; break;
}
}
if (log_get_errorcount (0))
g10_exit(2);
if (opt.verbose > 1)
set_packet_list_mode(1);
/* Note: We open all keyrings in read-only mode (flag value: 8). */
if (!nrings) /* No keyring given: use default one. */
keydb_add_resource ("trustedkeys" EXTSEP_S "gpg", 8, 0);
for (sl = nrings; sl; sl = sl->next)
keydb_add_resource (sl->d, 8, 0 );
FREE_STRLIST (nrings);
if ( (rc = verify_signatures( argc, argv ) ))
log_error("verify signatures failed: %s\n", g10_errstr(rc) );
/* cleanup */
g10_exit (0);
return 8; /*NOTREACHED*/
}
void
g10_exit( int rc )
{
rc = rc? rc : log_get_errorcount(0)? 2 : g10_errors_seen? 1 : 0;
exit(rc );
}
/* Stub:
* We have to override the trustcheck from pkclist.c becuase
* this utility assumes that all keys in the keyring are trustworthy
*/
int
check_signatures_trust( PKT_signature *sig )
{
(void)sig;
return 0;
}
void
read_trust_options(byte *trust_model, ulong *created, ulong *nextcheck,
byte *marginals, byte *completes, byte *cert_depth,
byte *min_cert_level)
{
(void)trust_model;
(void)created;
(void)nextcheck;
(void)marginals;
(void)completes;
(void)cert_depth;
(void)min_cert_level;
}
/* Stub:
* We don't have the trustdb , so we have to provide some stub functions
* instead
*/
int
cache_disabled_value(PKT_public_key *pk)
{
(void)pk;
return 0;
}
void
check_trustdb_stale(void)
{
}
int
get_validity_info (PKT_public_key *pk, PKT_user_id *uid)
{
(void)pk;
(void)uid;
return '?';
}
unsigned int
get_validity (PKT_public_key *pk, PKT_user_id *uid)
{
(void)pk;
(void)uid;
return 0;
}
const char *
trust_value_to_string (unsigned int value)
{
(void)value;
return "err";
}
const char *
uid_trust_string_fixed (PKT_public_key *key, PKT_user_id *uid)
{
(void)key;
(void)uid;
return "err";
}
int
get_ownertrust_info (PKT_public_key *pk)
{
(void)pk;
return '?';
}
unsigned int
get_ownertrust (PKT_public_key *pk)
{
(void)pk;
return TRUST_UNKNOWN;
}
/* Stubs:
* Because we only work with trusted keys, it does not make sense to
* get them from a keyserver
*/
struct keyserver_spec *
keyserver_match (struct keyserver_spec *spec)
{
(void)spec;
return NULL;
}
int
keyserver_import_keyid (u32 *keyid, void *dummy)
{
(void)keyid;
(void)dummy;
return -1;
}
int
keyserver_import_cert (const char *name)
{
(void)name;
return -1;
}
int
keyserver_import_pka (const char *name,unsigned char *fpr)
{
(void)name;
(void)fpr;
return -1;
}
int
keyserver_import_name (const char *name,struct keyserver_spec *spec)
{
(void)name;
(void)spec;
return -1;
}
int
keyserver_import_ldap (const char *name)
{
(void)name;
return -1;
}
/* Stub:
* No encryption here but mainproc links to these functions.
*/
int
get_session_key (PKT_pubkey_enc *k, DEK *dek)
{
(void)k;
(void)dek;
return G10ERR_GENERAL;
}
/* Stub: */
int
get_override_session_key (DEK *dek, const char *string)
{
(void)dek;
(void)string;
return G10ERR_GENERAL;
}
/* Stub: */
int
decrypt_data (void *procctx, PKT_encrypted *ed, DEK *dek)
{
(void)procctx;
(void)ed;
(void)dek;
return G10ERR_GENERAL;
}
/* Stub:
* No interactive commands, so we don't need the helptexts
*/
void
display_online_help (const char *keyword)
{
(void)keyword;
}
/* Stub:
* We don't use secret keys, but getkey.c links to this
*/
int
check_secret_key (PKT_secret_key *sk, int n)
{
(void)sk;
(void)n;
return G10ERR_GENERAL;
}
/* Stub:
* No secret key, so no passphrase needed
*/
DEK *
passphrase_to_dek (u32 *keyid, int pubkey_algo,
int cipher_algo, STRING2KEY *s2k, int mode,
const char *tmp, int *canceled)
{
(void)keyid;
(void)pubkey_algo;
(void)cipher_algo;
(void)s2k;
(void)mode;
(void)tmp;
if (canceled)
*canceled = 0;
return NULL;
}
void
passphrase_clear_cache (u32 *keyid, const char *cacheid, int algo)
{
(void)keyid;
(void)cacheid;
(void)algo;
}
struct keyserver_spec *
parse_preferred_keyserver(PKT_signature *sig)
{
(void)sig;
return NULL;
}
struct keyserver_spec *
parse_keyserver_uri (const char *uri, int require_scheme,
const char *configname, unsigned int configlineno)
{
(void)uri;
(void)require_scheme;
(void)configname;
(void)configlineno;
return NULL;
}
void
free_keyserver_spec (struct keyserver_spec *keyserver)
{
(void)keyserver;
}
/* Stubs to avoid linking to photoid.c */
void
show_photos (const struct user_attribute *attrs, int count, PKT_public_key *pk)
{
(void)attrs;
(void)count;
(void)pk;
}
int
parse_image_header (const struct user_attribute *attr, byte *type, u32 *len)
{
(void)attr;
(void)type;
(void)len;
return 0;
}
char *
image_type_to_string (byte type, int string)
{
(void)type;
(void)string;
return NULL;
}
#ifdef ENABLE_CARD_SUPPORT
int
agent_scd_getattr (const char *name, struct agent_card_info_s *info)
{
(void)name;
(void)info;
return 0;
}
#endif /* ENABLE_CARD_SUPPORT */
/* We do not do any locking, so use these stubs here */
void
disable_dotlock (void)
{
}
DOTLOCK
create_dotlock (const char *file_to_lock)
{
(void)file_to_lock;
return NULL;
}
void
destroy_dotlock (DOTLOCK h)
{
(void)h;
}
int
make_dotlock (DOTLOCK h, long timeout)
{
(void)h;
(void)timeout;
return 0;
}
int
release_dotlock (DOTLOCK h)
{
(void)h;
return 0;
}
void
remove_lockfiles (void)
{
}