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gnupg/g10/gpgv.c
NIIBE Yutaka e32c575e0f 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.

--

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 10:20:02 +09:00

700 lines
13 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 "util.h"
#include "packet.h"
#include "iobuf.h"
#include "main.h"
#include "options.h"
#include "keydb.h"
#include "trustdb.h"
#include "filter.h"
#include "ttyio.h"
#include "i18n.h"
#include "sysutils.h"
#include "status.h"
#include "call-agent.h"
#include "../common/init.h"
enum cmd_and_opt_values {
aNull = 0,
oQuiet = 'q',
oVerbose = 'v',
oBatch = 500,
oKeyring,
oIgnoreTimeConflict,
oStatusFD,
oLoggerFD,
oHomedir,
oWeakDigest,
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_s_s (oWeakDigest, "weak-digest",
N_("|ALGO|reject signatures made with ALGO")),
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 = "@GPG@v (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;
ctrl_t ctrl;
early_system_init ();
set_strusage (my_strusage);
log_set_prefix ("gpgv", 1);
/* Make sure that our subsystems are ready. */
i18n_init();
init_common_subsystems (&argc, &argv);
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.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.weak_digests = NULL;
tty_no_terminal(1);
tty_batchmode(1);
dotlock_disable ();
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
additional_weak_digest("MD5");
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: gnupg_set_homedir (pargs.r.ret_str); break;
case oWeakDigest:
additional_weak_digest(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. */
if (!nrings) /* No keyring given: use default one. */
keydb_add_resource ("trustedkeys" EXTSEP_S "kbx",
(KEYDB_RESOURCE_FLAG_READONLY
|KEYDB_RESOURCE_FLAG_GPGVDEF));
for (sl = nrings; sl; sl = sl->next)
keydb_add_resource (sl->d, KEYDB_RESOURCE_FLAG_READONLY);
FREE_STRLIST (nrings);
ctrl = xcalloc (1, sizeof *ctrl);
if ((rc = verify_signatures (ctrl, argc, argv)))
log_error("verify signatures failed: %s\n", gpg_strerror (rc) );
xfree (ctrl);
/* 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 because
* this utility assumes that all keys in the keyring are trustworthy
*/
int
check_signatures_trust (ctrl_t ctrl, PKT_signature *sig)
{
(void)ctrl;
(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 (ctrl_t ctrl)
{
(void)ctrl;
}
int
get_validity_info (ctrl_t ctrl, PKT_public_key *pk, PKT_user_id *uid)
{
(void)ctrl;
(void)pk;
(void)uid;
return '?';
}
unsigned int
get_validity (ctrl_t ctrl, PKT_public_key *pk, PKT_user_id *uid,
PKT_signature *sig, int may_ask)
{
(void)ctrl;
(void)pk;
(void)uid;
(void)sig;
(void)may_ask;
return 0;
}
const char *
trust_value_to_string (unsigned int value)
{
(void)value;
return "err";
}
const char *
uid_trust_string_fixed (ctrl_t ctrl, PKT_public_key *key, PKT_user_id *uid)
{
(void)ctrl;
(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_any_configured (ctrl_t ctrl)
{
(void)ctrl;
return 0;
}
int
keyserver_import_keyid (u32 *keyid, void *dummy)
{
(void)keyid;
(void)dummy;
return -1;
}
int
keyserver_import_fprint (ctrl_t ctrl, const byte *fprint,size_t fprint_len,
struct keyserver_spec *keyserver)
{
(void)ctrl;
(void)fprint;
(void)fprint_len;
(void)keyserver;
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;
}
gpg_error_t
keyserver_import_wkd (ctrl_t ctrl, const char *name,
unsigned char **fpr, size_t *fpr_len)
{
(void)ctrl;
(void)name;
(void)fpr;
(void)fpr_len;
return GPG_ERR_BUG;
}
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;
}
gpg_error_t
read_key_from_file (ctrl_t ctrl, const char *fname, kbnode_t *r_keyblock)
{
(void)ctrl;
(void)fname;
(void)r_keyblock;
return -1;
}
/* Stub:
* No encryption here but mainproc links to these functions.
*/
gpg_error_t
get_session_key (ctrl_t ctrl, PKT_pubkey_enc *k, DEK *dek)
{
(void)ctrl;
(void)k;
(void)dek;
return GPG_ERR_GENERAL;
}
/* Stub: */
gpg_error_t
get_override_session_key (DEK *dek, const char *string)
{
(void)dek;
(void)string;
return GPG_ERR_GENERAL;
}
/* Stub: */
int
decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
{
(void)ctrl;
(void)procctx;
(void)ed;
(void)dek;
return GPG_ERR_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_public_key *pk, int n)
{
(void)pk;
(void)n;
return GPG_ERR_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
dotlock_disable (void)
{
}
dotlock_t
dotlock_create (const char *file_to_lock, unsigned int flags)
{
(void)file_to_lock;
(void)flags;
return NULL;
}
void
dotlock_destroy (dotlock_t h)
{
(void)h;
}
int
dotlock_take (dotlock_t h, long timeout)
{
(void)h;
(void)timeout;
return 0;
}
int
dotlock_release (dotlock_t h)
{
(void)h;
return 0;
}
void
dotlock_remove_lockfiles (void)
{
}
gpg_error_t
agent_probe_secret_key (ctrl_t ctrl, PKT_public_key *pk)
{
(void)ctrl;
(void)pk;
return gpg_error (GPG_ERR_NO_SECKEY);
}
gpg_error_t
agent_probe_any_secret_key (ctrl_t ctrl, kbnode_t keyblock)
{
(void)ctrl;
(void)keyblock;
return gpg_error (GPG_ERR_NO_SECKEY);
}
gpg_error_t
agent_get_keyinfo (ctrl_t ctrl, const char *hexkeygrip,
char **r_serialno, int *r_cleartext)
{
(void)ctrl;
(void)hexkeygrip;
(void)r_cleartext;
*r_serialno = NULL;
return gpg_error (GPG_ERR_NO_SECKEY);
}
gpg_error_t
gpg_dirmngr_get_pka (ctrl_t ctrl, const char *userid,
unsigned char **r_fpr, size_t *r_fprlen,
char **r_url)
{
(void)ctrl;
(void)userid;
if (r_fpr)
*r_fpr = NULL;
if (r_fprlen)
*r_fprlen = 0;
if (r_url)
*r_url = NULL;
return gpg_error (GPG_ERR_NOT_FOUND);
}
gpg_error_t
export_pubkey_buffer (ctrl_t ctrl, const char *keyspec, unsigned int options,
export_stats_t stats,
kbnode_t *r_keyblock, void **r_data, size_t *r_datalen)
{
(void)ctrl;
(void)keyspec;
(void)options;
(void)stats;
*r_keyblock = NULL;
*r_data = NULL;
*r_datalen = 0;
return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
}
gpg_error_t
tofu_get_policy (ctrl_t ctrl, PKT_public_key *pk, PKT_user_id *user_id,
enum tofu_policy *policy)
{
(void)ctrl;
(void)pk;
(void)user_id;
(void)policy;
return gpg_error (GPG_ERR_GENERAL);
}
const char *
tofu_policy_str (enum tofu_policy policy)
{
(void)policy;
return "unknown";
}
void
tofu_begin_batch_update (void)
{
}
void
tofu_end_batch_update (void)
{
}