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gnupg/g10/gpgv.c
NIIBE Yutaka cf01cf8b88 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 e32c575e0f3704e7563048eea6d26844bdfc494b)

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 10:41:08 +09:00

449 lines
12 KiB
C

/* gpgv.c - The GnuPG signature verify utility
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2005, 2006,
* 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
#include <stdio.h>
#include <readline/readline.h>
#endif
#define INCLUDED_BY_MAIN_MODULE 1
#include "packet.h"
#include "iobuf.h"
#include "memory.h"
#include "util.h"
#include "main.h"
#include "options.h"
#include "keydb.h"
#include "trustdb.h"
#include "mpi.h"
#include "cipher.h"
#include "filter.h"
#include "ttyio.h"
#include "i18n.h"
#include "status.h"
#include "cardglue.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[] = {
{ 301, NULL, 0, N_("@\nOptions:\n ") },
{ oVerbose, "verbose", 0, N_("verbose") },
{ oQuiet, "quiet", 0, N_("be somewhat more quiet") },
{ oKeyring, "keyring" ,2, N_("take the keys from this keyring")},
{ oIgnoreTimeConflict, "ignore-time-conflict", 0,
N_("make timestamp conflicts only a warning") },
{ oStatusFD, "status-fd" ,1, N_("|FD|write status info to this FD") },
{ oLoggerFD, "logger-fd",1, "@" },
{ oHomedir, "homedir", 2, "@" }, /* defaults to "~/.gnupg" */
{ oWeakDigest, "weak-digest", 2, "@" }, /* defaults to "~/.gnupg" */
{0} };
int g10_errors_seen = 0;
const char *
strusage( int level )
{
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 <gnupg-bugs@gnu.org>.\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;
default: p = default_strusage(level);
}
return p;
}
static void
i18n_init(void)
{
#ifdef USE_SIMPLE_GETTEXT
set_gettext_file (PACKAGE, "Software\\GNU\\GnuPG");
#else
#ifdef ENABLE_NLS
setlocale( LC_ALL, "" );
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain( PACKAGE );
#endif
#endif
}
int
main( int argc, char **argv )
{
ARGPARSE_ARGS pargs;
int rc=0;
STRLIST sl;
STRLIST nrings=NULL;
unsigned configlineno;
log_set_name("gpgv");
init_signals();
i18n_init();
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.weak_digests = NULL;
opt.homedir = default_homedir ();
tty_no_terminal(1);
tty_batchmode(1);
dotlock_disable ();
set_native_charset (NULL); /* Try to auto set the character set */
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: g10_opt_verbose++;
opt.verbose++; opt.list_sigs=1; 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_logfile( NULL, pargs.r.ret_int ); break;
case oHomedir: opt.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 = 2; break;
}
}
if( log_get_errorcount(0) )
g10_exit(2);
g10_opt_homedir = opt.homedir;
if( opt.verbose > 1 )
set_packet_list_mode(1);
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; /*NEVER REACHED*/
}
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 )
{
return 0;
}
void
read_trust_options(byte *trust_model,ulong *created,ulong *nextcheck,
byte *marginals,byte *completes,byte *cert_depth,
byte *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)
{
return 0;
}
void
check_trustdb_stale(void) {}
int
get_validity_info (PKT_public_key *pk, PKT_user_id *uid)
{
return '?';
}
unsigned int
get_validity (PKT_public_key *pk, PKT_user_id *uid)
{
return 0;
}
const char *
trust_value_to_string (unsigned int value)
{
return "err";
}
const char *
uid_trust_string_fixed(PKT_public_key *key,PKT_user_id *uid)
{
return "err";
}
int
get_ownertrust_info (PKT_public_key *pk)
{
return '?';
}
unsigned int
get_ownertrust (PKT_public_key *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) { return NULL; }
int
keyserver_import_keyid( u32 *keyid, void *dummy )
{
return -1;
}
int
keyserver_import_cert(const char *name) { return -1; }
int
keyserver_import_pka(const char *name,unsigned char *fpr) { return -1; }
int
keyserver_import_name(const char *name,struct keyserver_spec *spec)
{
return -1;
}
int
keyserver_import_ldap(const char *name) { return -1; }
/* Stub:
* No encryption here but mainproc links to these functions.
*/
int
get_session_key( PKT_pubkey_enc *k, DEK *dek )
{
return G10ERR_GENERAL;
}
/* Stub: */
int
get_override_session_key( DEK *dek, const char *string )
{
return G10ERR_GENERAL;
}
/* Stub: */
int
decrypt_data( void *procctx, PKT_encrypted *ed, DEK *dek )
{
return G10ERR_GENERAL;
}
/* Stub:
* No interactive commnds, so we don't need the helptexts
*/
void
display_online_help( const char *keyword )
{
}
/* Stub:
* We don't use secret keys, but getkey.c links to this
*/
int
check_secret_key( PKT_secret_key *sk, int 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)
{
if (canceled)
*canceled = 0;
return NULL;
}
struct keyserver_spec *parse_preferred_keyserver(PKT_signature *sig) {return NULL;}
struct keyserver_spec *parse_keyserver_uri(const char *uri,int require_scheme,
const char *configname,
unsigned int configlineno)
{
return NULL;
}
void free_keyserver_spec(struct keyserver_spec *keyserver) {}
/* Stubs to avoid linking to photoid.c */
void show_photos(const struct user_attribute *attrs,int count,PKT_public_key *pk) {}
int parse_image_header(const struct user_attribute *attr,byte *type,u32 *len) {return 0;}
char *image_type_to_string(byte type,int string) {return NULL;}
#ifdef ENABLE_CARD_SUPPORT
int agent_scd_getattr (const char *name, struct agent_card_info_s *info) {return 0;}
#endif /* ENABLE_CARD_SUPPORT */
/* Stubs to void linking to ../cipher/cipher.c */
int string_to_cipher_algo( const char *string ) { return 0; }
const char *cipher_algo_to_string( int algo ) { return "?";}
void disable_cipher_algo( int algo ) {}
int check_cipher_algo( int algo ) { return -1;}
unsigned int cipher_get_keylen( int algo ) { return 0; }
unsigned int cipher_get_blocksize( int algo ) {return 0;}
CIPHER_HANDLE cipher_open( int algo, int mode, int secure ) { return NULL;}
void cipher_close( CIPHER_HANDLE c ) {}
int cipher_setkey( CIPHER_HANDLE c, byte *key, unsigned keylen ) { return -1;}
void cipher_setiv( CIPHER_HANDLE c, const byte *iv, unsigned ivlen ){}
void cipher_encrypt( CIPHER_HANDLE c, byte *outbuf,
byte *inbuf, unsigned nbytes ) {}
void cipher_decrypt( CIPHER_HANDLE c, byte *outbuf,
byte *inbuf, unsigned nbytes ) {}
void cipher_sync( CIPHER_HANDLE c ) {}
/* Stubs to avoid linking to ../cipher/random.c */
void random_dump_stats(void) {}
int quick_random_gen( int onoff ) { return -1;}
void randomize_buffer( byte *buffer, size_t length, int level ) {}
void randomize_mpi (MPI mpi, size_t nbits, int level) {}
int random_is_faked() { return -1;}
byte *get_random_bits( size_t nbits, int level, int secure ) { return NULL;}
void set_random_seed_file( const char *name ) {}
void update_random_seed_file() {}
void fast_random_poll() {}
/* Stubs to avoid linking of ../cipher/primegen.c */
void register_primegen_progress ( void (*cb)( void *, int), void *cb_data ) {}
MPI generate_secret_prime( unsigned nbits ) { return NULL;}
MPI generate_public_prime( unsigned nbits ) { return NULL;}
MPI generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
MPI g, MPI **ret_factors ) { return NULL;}
/* Do not link to ../cipher/rndlinux.c */
void rndlinux_constructor(void) {}
/* Stubs to avoid linking to ../util/ttyio.c */
int tty_batchmode( int onoff ) { return 0; }
void tty_printf( const char *fmt, ... ) { }
void tty_fprintf (FILE *fp, const char *fmt, ... ) { }
void tty_print_string( const byte *p, size_t n ) { }
void tty_print_utf8_string( const byte *p, size_t n ) {}
void tty_print_utf8_string2( const byte *p, size_t n, size_t max_n ) {}
char *tty_get( const char *prompt ) { return NULL;}
char *tty_get_hidden( const char *prompt ) {return NULL; }
void tty_kill_prompt(void) {}
int tty_get_answer_is_yes( const char *prompt ) {return 0;}
int tty_no_terminal(int onoff) {return 0;}
void tty_cleanup_after_signal (void) {}
#ifdef __VMS
FILE *ttyfp_is (void) { return stderr; }
void init_ttyfp (void) { }
#endif /*__VMS*/
#ifdef HAVE_LIBREADLINE
void tty_enable_completion(rl_completion_func_t *completer) {}
void tty_disable_completion(void) {}
void rl_cleanup_after_signal (void) {}
void rl_free_line_state (void) {}
#endif
/* 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)
{ return NULL; }
void dotlock_destroy (dotlock_t h, int reclaim) {}
int dotlock_take (dotlock_t h, long timeout) { return 0;}
int dotlock_release (dotlock_t h) {return 0;}
void dotlock_remove_lockfiles (int reclaim) {}