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gnupg/g10/gpgv.c
Werner Koch e081a601f7
gpg: Allow decryption of symencr even for non-compliant cipher. 
* g10/decrypt-data.c (decrypt_data): Add arg compliance_error.  Adjust
all callers.  Fail on compliance error only in --require-compliance
mode.  Make sure to return an error if the buffer is missing; actually
that should be an assert.
* g10/mainproc.c (proc_encrypted): Delay printing of the compliance
mode status.  Consult the compliance error now returned by
decrypt_data.
--

The actual case here is that we fail hard if a message has been AEAD
encrypted with one AEAD capable key and also with one passphrase.  In
general the preference system takes care of not using AEAD if one
recipient's key does not support it.  However, if the sender uses her
own AEAD-capable key _and_ a passphrase the message will be AEAD
encrypted.  This change allows to decrypt that anyway along with a
warning message.

Note that this does currently not work in 2.3 due to a non-compliant
libgcrypt.  We will however, backport this to 2.2.
2022-03-18 11:55:17 +01:00

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/* gpgv.c - The GnuPG signature verify utility
* Copyright (C) 1998-2020 Free Software Foundation, Inc.
* Copyright (C) 1998-2019 Werner Koch
* Copyright (C) 2015-2020 g10 Code GmbH
*
* 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/>.
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#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 "../common/util.h"
#include "packet.h"
#include "../common/iobuf.h"
#include "main.h"
#include "options.h"
#include "keydb.h"
#include "trustdb.h"
#include "filter.h"
#include "../common/ttyio.h"
#include "../common/i18n.h"
#include "../common/sysutils.h"
#include "../common/status.h"
#include "call-agent.h"
#include "../common/init.h"
enum cmd_and_opt_values {
aNull = 0,
oQuiet = 'q',
oVerbose = 'v',
oOutput = 'o',
oBatch = 500,
oKeyring,
oIgnoreTimeConflict,
oStatusFD,
oLoggerFD,
oLoggerFile,
oHomedir,
oWeakDigest,
oEnableSpecialFilenames,
oDebug,
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_s (oOutput, "output", N_("|FILE|write output to 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 (oLoggerFile, "log-file", "@"),
ARGPARSE_s_s (oHomedir, "homedir", "@"),
ARGPARSE_s_s (oWeakDigest, "weak-digest",
N_("|ALGO|reject signatures made with ALGO")),
ARGPARSE_s_n (oEnableSpecialFilenames, "enable-special-filenames", "@"),
ARGPARSE_s_s (oDebug, "debug", "@"),
ARGPARSE_end ()
};
/* The list of supported debug flags. */
static struct debug_flags_s debug_flags [] =
{
{ DBG_PACKET_VALUE , "packet" },
{ DBG_MPI_VALUE , "mpi" },
{ DBG_CRYPTO_VALUE , "crypto" },
{ DBG_FILTER_VALUE , "filter" },
{ DBG_IOBUF_VALUE , "iobuf" },
{ DBG_MEMORY_VALUE , "memory" },
{ DBG_CACHE_VALUE , "cache" },
{ DBG_MEMSTAT_VALUE, "memstat" },
{ DBG_TRUST_VALUE , "trust" },
{ DBG_HASHING_VALUE, "hashing" },
{ DBG_IPC_VALUE , "ipc" },
{ DBG_CLOCK_VALUE , "clock" },
{ DBG_LOOKUP_VALUE , "lookup" },
{ DBG_EXTPROG_VALUE, "extprog" },
{ 0, NULL }
};
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 9: p = "GPL-3.0-or-later"; break;
case 11: p = "@GPG@v (GnuPG)";
break;
case 13: p = VERSION; break;
case 14: p = GNUPG_DEF_COPYRIGHT_LINE; 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;
ctrl_t ctrl;
early_system_init ();
set_strusage (my_strusage);
log_set_prefix ("gpgv", GPGRT_LOG_WITH_PREFIX);
/* Make sure that our subsystems are ready. */
i18n_init();
init_common_subsystems (&argc, &argv);
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.answer_yes = 1;
opt.weak_digests = NULL;
tty_no_terminal(1);
tty_batchmode(1);
dotlock_disable ();
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
additional_weak_digest("MD5");
gnupg_initialize_compliance (GNUPG_MODULE_NAME_GPG);
pargs.argc = &argc;
pargs.argv = &argv;
pargs.flags= ARGPARSE_FLAG_KEEP;
while (gnupg_argparser (&pargs, opts, NULL))
{
switch (pargs.r_opt)
{
case ARGPARSE_CONFFILE: break;
case oQuiet: opt.quiet = 1; break;
case oVerbose:
opt.verbose++;
opt.list_sigs=1;
gcry_control (GCRYCTL_SET_VERBOSITY, (int)opt.verbose);
break;
case oDebug:
if (parse_debug_flag (pargs.r.ret_str, &opt.debug, debug_flags))
{
pargs.r_opt = ARGPARSE_INVALID_ARG;
pargs.err = ARGPARSE_PRINT_ERROR;
}
break;
case oKeyring: append_to_strlist( &nrings, pargs.r.ret_str); break;
case oOutput: opt.outfile = pargs.r.ret_str; break;
case oStatusFD:
set_status_fd (translate_sys2libc_fd_int (pargs.r.ret_int, 1));
break;
case oLoggerFD:
log_set_fd (translate_sys2libc_fd_int (pargs.r.ret_int, 1));
break;
case oLoggerFile:
log_set_file (pargs.r.ret_str);
log_set_prefix (NULL, (GPGRT_LOG_WITH_PREFIX
| GPGRT_LOG_WITH_TIME
| GPGRT_LOG_WITH_PID) );
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;
case oEnableSpecialFilenames:
enable_special_filenames ();
break;
default : pargs.err = ARGPARSE_PRINT_ERROR; break;
}
}
gnupg_argparse (NULL, &pargs, NULL); /* Release internal state. */
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) );
keydb_release (ctrl->cached_getkey_kdb);
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 (ctrl_t ctrl,
byte *trust_model, ulong *created, ulong *nextcheck,
byte *marginals, byte *completes, byte *cert_depth,
byte *min_cert_level)
{
(void)ctrl;
(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 (ctrl_t ctrl, PKT_public_key *pk)
{
(void)ctrl;
(void)pk;
return 0;
}
void
check_trustdb_stale (ctrl_t ctrl)
{
(void)ctrl;
}
int
get_validity_info (ctrl_t ctrl, kbnode_t kb, PKT_public_key *pk,
PKT_user_id *uid)
{
(void)ctrl;
(void)kb;
(void)pk;
(void)uid;
return '?';
}
unsigned int
get_validity (ctrl_t ctrl, kbnode_t kb, PKT_public_key *pk, PKT_user_id *uid,
PKT_signature *sig, int may_ask)
{
(void)ctrl;
(void)kb;
(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 (ctrl_t ctrl, PKT_public_key *pk, int no_create)
{
(void)ctrl;
(void)pk;
(void)no_create;
return '?';
}
unsigned int
get_ownertrust (ctrl_t ctrl, PKT_public_key *pk)
{
(void)ctrl;
(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, unsigned int flags)
{
(void)keyid;
(void)dummy;
(void)flags;
return -1;
}
int
keyserver_import_fprint (ctrl_t ctrl, const byte *fprint,size_t fprint_len,
struct keyserver_spec *keyserver, unsigned int flags)
{
(void)ctrl;
(void)fprint;
(void)fprint_len;
(void)keyserver;
(void)flags;
return -1;
}
int
keyserver_import_fprint_ntds (ctrl_t ctrl,
const byte *fprint, size_t fprint_len)
{
(void)ctrl;
(void)fprint;
(void)fprint_len;
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 int flags,
unsigned char **fpr, size_t *fpr_len)
{
(void)ctrl;
(void)name;
(void)flags;
(void)fpr;
(void)fpr_len;
return GPG_ERR_BUG;
}
int
keyserver_import_mbox (const char *name,struct keyserver_spec *spec)
{
(void)name;
(void)spec;
return -1;
}
int
keyserver_import_ntds (ctrl_t ctrl, const char *mbox,
unsigned char **fpr, size_t *fprlen)
{
(void)ctrl;
(void)mbox;
(void)fpr;
(void)fprlen;
return -1;
}
int
keyserver_import_ldap (const char *name)
{
(void)name;
return -1;
}
gpg_error_t
read_key_from_file_or_buffer (ctrl_t ctrl, const char *fname,
const void *buffer, size_t buflen,
kbnode_t *r_keyblock)
{
(void)ctrl;
(void)fname;
(void)buffer;
(void)buflen;
(void)r_keyblock;
return -1;
}
gpg_error_t
import_included_key_block (ctrl_t ctrl, kbnode_t keyblock)
{
(void)ctrl;
(void)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,
int *compliance_error)
{
(void)ctrl;
(void)procctx;
(void)ed;
(void)dek;
(void)compliance_error;
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 (int cipher_algo, STRING2KEY *s2k, int create, int nocache,
const char *tmp, unsigned int flags, int *canceled)
{
(void)cipher_algo;
(void)s2k;
(void)create;
(void)nocache;
(void)tmp;
(void)flags;
if (canceled)
*canceled = 0;
return NULL;
}
void
passphrase_clear_cache (const char *cacheid)
{
(void)cacheid;
}
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,
const void *prefix, size_t prefixlen,
export_stats_t stats,
kbnode_t *r_keyblock, void **r_data, size_t *r_datalen)
{
(void)ctrl;
(void)keyspec;
(void)options;
(void)prefix;
(void)prefixlen;
(void)stats;
*r_keyblock = NULL;
*r_data = NULL;
*r_datalen = 0;
return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
}
gpg_error_t
tofu_write_tfs_record (ctrl_t ctrl, estream_t fp,
PKT_public_key *pk, const char *user_id)
{
(void)ctrl;
(void)fp;
(void)pk;
(void)user_id;
return gpg_error (GPG_ERR_GENERAL);
}
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 (ctrl_t ctrl)
{
(void)ctrl;
}
void
tofu_end_batch_update (ctrl_t ctrl)
{
(void)ctrl;
}
gpg_error_t
tofu_notice_key_changed (ctrl_t ctrl, kbnode_t kb)
{
(void) ctrl;
(void) kb;
return 0;
}
int
get_revocation_reason (PKT_signature *sig, char **r_reason,
char **r_comment, size_t *r_commentlen)
{
(void)sig;
(void)r_commentlen;
if (r_reason)
*r_reason = NULL;
if (r_comment)
*r_comment = NULL;
return 0;
}
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