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gnupg/agent/protect-tool.c
Werner Koch 7777e68d04 Implement unattended OpenPGP secret key import.
* agent/command.c (cmd_import_key): Add option --unattended.
* agent/cvt-openpgp.c (convert_transfer_key): New.
(do_unprotect): Factor some code out to ...
(prepare_unprotect): new function.
(convert_from_openpgp): Factor all code out to ...
(convert_from_openpgp_main): this.  Add arg 'passphrase'.  Implement
openpgp-native protection modes.
(convert_from_openpgp_native): New.
* agent/t-protect.c (convert_from_openpgp_native): New dummy fucntion
* agent/protect-tool.c (convert_from_openpgp_native): Ditto.
* agent/protect.c (agent_unprotect): Add arg CTRL.  Adjust all
callers.  Support openpgp-native protection.
* g10/call-agent.c (agent_import_key): Add arg 'unattended'.
* g10/import.c (transfer_secret_keys): Use unattended in batch mode.
--

With the gpg-agent taking care of the secret keys, the user needs to
migrate existing keys from secring.gpg to the agent.  This and also
the standard import of secret keys required the user to unprotect the
secret keys first, so that gpg-agent was able to re-protected them
using its own scheme.  With many secret keys this is quite some
usability hurdle.  In particular if a passphrase is not instantly
available.

To make this migration smoother, this patch implements an unattended
key import/migration which delays the conversion to the gpg-agent
format until the key is actually used.  For example:

   gpg2 --batch --import mysecretkey.gpg

works without any user interaction due to the use of --batch.  Now if
a key is used (e.g. "gpg2 -su USERID_FROM_MYSECRETKEY foo"), gpg-agent
has to ask for the passphrase anyway, converts the key from the
openpgp format to the internal format, signs, re-encrypts the key and
tries to store it in the gpg-agent format to the disk.  The next time,
the internal format of the key is used.

This patch has only been tested with the old demo keys, more tests
with other protection formats and no protection are needed.

Signed-off-by: Werner Koch <wk@gnupg.org>
2013-05-22 10:14:57 +02:00

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/* protect-tool.c - A tool to test the secret key protection
* Copyright (C) 2002, 2003, 2004, 2006 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 <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sys/stat.h>
#include <unistd.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#ifdef HAVE_LANGINFO_CODESET
#include <langinfo.h>
#endif
#ifdef HAVE_DOSISH_SYSTEM
#include <fcntl.h> /* for setmode() */
#endif
#define JNLIB_NEED_LOG_LOGV
#include "agent.h"
#include "i18n.h"
#include "get-passphrase.h"
#include "sysutils.h"
#include "../common/init.h"
enum cmd_and_opt_values
{
aNull = 0,
oVerbose = 'v',
oArmor = 'a',
oPassphrase = 'P',
oProtect = 'p',
oUnprotect = 'u',
oNoVerbose = 500,
oShadow,
oShowShadowInfo,
oShowKeygrip,
oS2Kcalibration,
oCanonical,
oStore,
oForce,
oHaveCert,
oNoFailOnExist,
oHomedir,
oPrompt,
oStatusMsg,
oAgentProgram
};
struct rsa_secret_key_s
{
gcry_mpi_t n; /* public modulus */
gcry_mpi_t e; /* public exponent */
gcry_mpi_t d; /* exponent */
gcry_mpi_t p; /* prime p. */
gcry_mpi_t q; /* prime q. */
gcry_mpi_t u; /* inverse of p mod q. */
};
static const char *opt_homedir;
static int opt_armor;
static int opt_canonical;
static int opt_store;
static int opt_force;
static int opt_no_fail_on_exist;
static int opt_have_cert;
static const char *opt_passphrase;
static char *opt_prompt;
static int opt_status_msg;
static const char *opt_agent_program;
static char *get_passphrase (int promptno);
static void release_passphrase (char *pw);
static ARGPARSE_OPTS opts[] = {
ARGPARSE_group (300, N_("@Commands:\n ")),
ARGPARSE_c (oProtect, "protect", "protect a private key"),
ARGPARSE_c (oUnprotect, "unprotect", "unprotect a private key"),
ARGPARSE_c (oShadow, "shadow", "create a shadow entry for a public key"),
ARGPARSE_c (oShowShadowInfo, "show-shadow-info", "return the shadow info"),
ARGPARSE_c (oShowKeygrip, "show-keygrip", "show the \"keygrip\""),
ARGPARSE_c (oS2Kcalibration, "s2k-calibration", "@"),
ARGPARSE_group (301, N_("@\nOptions:\n ")),
ARGPARSE_s_n (oVerbose, "verbose", "verbose"),
ARGPARSE_s_n (oArmor, "armor", "write output in advanced format"),
ARGPARSE_s_n (oCanonical, "canonical", "write output in canonical format"),
ARGPARSE_s_s (oPassphrase, "passphrase", "|STRING|use passphrase STRING"),
ARGPARSE_s_n (oHaveCert, "have-cert",
"certificate to export provided on STDIN"),
ARGPARSE_s_n (oStore, "store",
"store the created key in the appropriate place"),
ARGPARSE_s_n (oForce, "force",
"force overwriting"),
ARGPARSE_s_n (oNoFailOnExist, "no-fail-on-exist", "@"),
ARGPARSE_s_s (oHomedir, "homedir", "@"),
ARGPARSE_s_s (oPrompt, "prompt",
"|ESCSTRING|use ESCSTRING as prompt in pinentry"),
ARGPARSE_s_n (oStatusMsg, "enable-status-msg", "@"),
ARGPARSE_s_s (oAgentProgram, "agent-program", "@"),
ARGPARSE_end ()
};
static const char *
my_strusage (int level)
{
const char *p;
switch (level)
{
case 11: p = "gpg-protect-tool (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: gpg-protect-tool [options] (-h for help)\n");
break;
case 41: p = _("Syntax: gpg-protect-tool [options] [args]\n"
"Secret key maintenance tool\n");
break;
default: p = NULL;
}
return p;
}
/* static void */
/* print_mpi (const char *text, gcry_mpi_t a) */
/* { */
/* char *buf; */
/* void *bufaddr = &buf; */
/* int rc; */
/* rc = gcry_mpi_aprint (GCRYMPI_FMT_HEX, bufaddr, NULL, a); */
/* if (rc) */
/* log_info ("%s: [error printing number: %s]\n", text, gpg_strerror (rc)); */
/* else */
/* { */
/* log_info ("%s: %s\n", text, buf); */
/* gcry_free (buf); */
/* } */
/* } */
static unsigned char *
make_canonical (const char *fname, const char *buf, size_t buflen)
{
int rc;
size_t erroff, len;
gcry_sexp_t sexp;
unsigned char *result;
rc = gcry_sexp_sscan (&sexp, &erroff, buf, buflen);
if (rc)
{
log_error ("invalid S-Expression in '%s' (off=%u): %s\n",
fname, (unsigned int)erroff, gpg_strerror (rc));
return NULL;
}
len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_CANON, NULL, 0);
assert (len);
result = xmalloc (len);
len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_CANON, result, len);
assert (len);
gcry_sexp_release (sexp);
return result;
}
static char *
make_advanced (const unsigned char *buf, size_t buflen)
{
int rc;
size_t erroff, len;
gcry_sexp_t sexp;
char *result;
rc = gcry_sexp_sscan (&sexp, &erroff, (const char*)buf, buflen);
if (rc)
{
log_error ("invalid canonical S-Expression (off=%u): %s\n",
(unsigned int)erroff, gpg_strerror (rc));
return NULL;
}
len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_ADVANCED, NULL, 0);
assert (len);
result = xmalloc (len);
len = gcry_sexp_sprint (sexp, GCRYSEXP_FMT_ADVANCED, result, len);
assert (len);
gcry_sexp_release (sexp);
return result;
}
static char *
read_file (const char *fname, size_t *r_length)
{
FILE *fp;
char *buf;
size_t buflen;
if (!strcmp (fname, "-"))
{
size_t nread, bufsize = 0;
fp = stdin;
#ifdef HAVE_DOSISH_SYSTEM
setmode ( fileno(fp) , O_BINARY );
#endif
buf = NULL;
buflen = 0;
#define NCHUNK 8192
do
{
bufsize += NCHUNK;
if (!buf)
buf = xmalloc (bufsize);
else
buf = xrealloc (buf, bufsize);
nread = fread (buf+buflen, 1, NCHUNK, fp);
if (nread < NCHUNK && ferror (fp))
{
log_error ("error reading '[stdin]': %s\n", strerror (errno));
xfree (buf);
return NULL;
}
buflen += nread;
}
while (nread == NCHUNK);
#undef NCHUNK
}
else
{
struct stat st;
fp = fopen (fname, "rb");
if (!fp)
{
log_error ("can't open '%s': %s\n", fname, strerror (errno));
return NULL;
}
if (fstat (fileno(fp), &st))
{
log_error ("can't stat '%s': %s\n", fname, strerror (errno));
fclose (fp);
return NULL;
}
buflen = st.st_size;
buf = xmalloc (buflen+1);
if (fread (buf, buflen, 1, fp) != 1)
{
log_error ("error reading '%s': %s\n", fname, strerror (errno));
fclose (fp);
xfree (buf);
return NULL;
}
fclose (fp);
}
*r_length = buflen;
return buf;
}
static unsigned char *
read_key (const char *fname)
{
char *buf;
size_t buflen;
unsigned char *key;
buf = read_file (fname, &buflen);
if (!buf)
return NULL;
key = make_canonical (fname, buf, buflen);
xfree (buf);
return key;
}
static void
read_and_protect (const char *fname)
{
int rc;
unsigned char *key;
unsigned char *result;
size_t resultlen;
char *pw;
key = read_key (fname);
if (!key)
return;
pw = get_passphrase (1);
rc = agent_protect (key, pw, &result, &resultlen, 0);
release_passphrase (pw);
xfree (key);
if (rc)
{
log_error ("protecting the key failed: %s\n", gpg_strerror (rc));
return;
}
if (opt_armor)
{
char *p = make_advanced (result, resultlen);
xfree (result);
if (!p)
return;
result = (unsigned char*)p;
resultlen = strlen (p);
}
fwrite (result, resultlen, 1, stdout);
xfree (result);
}
static void
read_and_unprotect (const char *fname)
{
int rc;
unsigned char *key;
unsigned char *result;
size_t resultlen;
char *pw;
gnupg_isotime_t protected_at;
key = read_key (fname);
if (!key)
return;
rc = agent_unprotect (NULL, key, (pw=get_passphrase (1)),
protected_at, &result, &resultlen);
release_passphrase (pw);
xfree (key);
if (rc)
{
if (opt_status_msg)
log_info ("[PROTECT-TOOL:] bad-passphrase\n");
log_error ("unprotecting the key failed: %s\n", gpg_strerror (rc));
return;
}
if (opt.verbose)
log_info ("key protection done at %.4s-%.2s-%.2s %.2s:%.2s:%s\n",
protected_at, protected_at+4, protected_at+6,
protected_at+9, protected_at+11, protected_at+13);
if (opt_armor)
{
char *p = make_advanced (result, resultlen);
xfree (result);
if (!p)
return;
result = (unsigned char*)p;
resultlen = strlen (p);
}
fwrite (result, resultlen, 1, stdout);
xfree (result);
}
static void
read_and_shadow (const char *fname)
{
int rc;
unsigned char *key;
unsigned char *result;
size_t resultlen;
unsigned char dummy_info[] = "(8:313233342:43)";
key = read_key (fname);
if (!key)
return;
rc = agent_shadow_key (key, dummy_info, &result);
xfree (key);
if (rc)
{
log_error ("shadowing the key failed: %s\n", gpg_strerror (rc));
return;
}
resultlen = gcry_sexp_canon_len (result, 0, NULL,NULL);
assert (resultlen);
if (opt_armor)
{
char *p = make_advanced (result, resultlen);
xfree (result);
if (!p)
return;
result = (unsigned char*)p;
resultlen = strlen (p);
}
fwrite (result, resultlen, 1, stdout);
xfree (result);
}
static void
show_shadow_info (const char *fname)
{
int rc;
unsigned char *key;
const unsigned char *info;
size_t infolen;
key = read_key (fname);
if (!key)
return;
rc = agent_get_shadow_info (key, &info);
xfree (key);
if (rc)
{
log_error ("get_shadow_info failed: %s\n", gpg_strerror (rc));
return;
}
infolen = gcry_sexp_canon_len (info, 0, NULL,NULL);
assert (infolen);
if (opt_armor)
{
char *p = make_advanced (info, infolen);
if (!p)
return;
fwrite (p, strlen (p), 1, stdout);
xfree (p);
}
else
fwrite (info, infolen, 1, stdout);
}
static void
show_file (const char *fname)
{
unsigned char *key;
size_t keylen;
char *p;
key = read_key (fname);
if (!key)
return;
keylen = gcry_sexp_canon_len (key, 0, NULL,NULL);
assert (keylen);
if (opt_canonical)
{
fwrite (key, keylen, 1, stdout);
}
else
{
p = make_advanced (key, keylen);
if (p)
{
fwrite (p, strlen (p), 1, stdout);
xfree (p);
}
}
xfree (key);
}
static void
show_keygrip (const char *fname)
{
unsigned char *key;
gcry_sexp_t private;
unsigned char grip[20];
int i;
key = read_key (fname);
if (!key)
return;
if (gcry_sexp_new (&private, key, 0, 0))
{
log_error ("gcry_sexp_new failed\n");
return;
}
xfree (key);
if (!gcry_pk_get_keygrip (private, grip))
{
log_error ("can't calculate keygrip\n");
return;
}
gcry_sexp_release (private);
for (i=0; i < 20; i++)
printf ("%02X", grip[i]);
putchar ('\n');
}
int
main (int argc, char **argv )
{
ARGPARSE_ARGS pargs;
int cmd = 0;
const char *fname;
set_strusage (my_strusage);
gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
log_set_prefix ("gpg-protect-tool", 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) );
}
setup_libgcrypt_logging ();
gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
opt_homedir = default_homedir ();
pargs.argc = &argc;
pargs.argv = &argv;
pargs.flags= 1; /* (do not remove the args) */
while (arg_parse (&pargs, opts) )
{
switch (pargs.r_opt)
{
case oVerbose: opt.verbose++; break;
case oArmor: opt_armor=1; break;
case oCanonical: opt_canonical=1; break;
case oHomedir: opt_homedir = pargs.r.ret_str; break;
case oAgentProgram: opt_agent_program = pargs.r.ret_str; break;
case oProtect: cmd = oProtect; break;
case oUnprotect: cmd = oUnprotect; break;
case oShadow: cmd = oShadow; break;
case oShowShadowInfo: cmd = oShowShadowInfo; break;
case oShowKeygrip: cmd = oShowKeygrip; break;
case oS2Kcalibration: cmd = oS2Kcalibration; break;
case oPassphrase: opt_passphrase = pargs.r.ret_str; break;
case oStore: opt_store = 1; break;
case oForce: opt_force = 1; break;
case oNoFailOnExist: opt_no_fail_on_exist = 1; break;
case oHaveCert: opt_have_cert = 1; break;
case oPrompt: opt_prompt = pargs.r.ret_str; break;
case oStatusMsg: opt_status_msg = 1; break;
default: pargs.err = ARGPARSE_PRINT_ERROR; break;
}
}
if (log_get_errorcount (0))
exit (2);
fname = "-";
if (argc == 1)
fname = *argv;
else if (argc > 1)
usage (1);
/* Set the information which can't be taken from envvars. */
gnupg_prepare_get_passphrase (GPG_ERR_SOURCE_DEFAULT,
opt.verbose,
opt_homedir,
opt_agent_program,
NULL, NULL, NULL);
if (opt_prompt)
opt_prompt = percent_plus_unescape (opt_prompt, 0);
if (cmd == oProtect)
read_and_protect (fname);
else if (cmd == oUnprotect)
read_and_unprotect (fname);
else if (cmd == oShadow)
read_and_shadow (fname);
else if (cmd == oShowShadowInfo)
show_shadow_info (fname);
else if (cmd == oShowKeygrip)
show_keygrip (fname);
else if (cmd == oS2Kcalibration)
{
if (!opt.verbose)
opt.verbose++; /* We need to see something. */
get_standard_s2k_count ();
}
else
show_file (fname);
agent_exit (0);
return 8; /*NOTREACHED*/
}
void
agent_exit (int rc)
{
rc = rc? rc : log_get_errorcount(0)? 2 : 0;
exit (rc);
}
/* Return the passphrase string and ask the agent if it has not been
set from the command line PROMPTNO select the prompt to display:
0 = default
1 = taken from the option --prompt
2 = for unprotecting a pkcs#12 object
3 = for protecting a new pkcs#12 object
4 = for protecting an imported pkcs#12 in our system
*/
static char *
get_passphrase (int promptno)
{
char *pw;
int err;
const char *desc;
char *orig_codeset;
int repeat = 0;
if (opt_passphrase)
return xstrdup (opt_passphrase);
orig_codeset = i18n_switchto_utf8 ();
if (promptno == 1 && opt_prompt)
{
desc = opt_prompt;
}
else if (promptno == 2)
{
desc = _("Please enter the passphrase to unprotect the "
"PKCS#12 object.");
}
else if (promptno == 3)
{
desc = _("Please enter the passphrase to protect the "
"new PKCS#12 object.");
repeat = 1;
}
else if (promptno == 4)
{
desc = _("Please enter the passphrase to protect the "
"imported object within the GnuPG system.");
repeat = 1;
}
else
desc = _("Please enter the passphrase or the PIN\n"
"needed to complete this operation.");
i18n_switchback (orig_codeset);
err = gnupg_get_passphrase (NULL, NULL, _("Passphrase:"), desc,
repeat, repeat, 1, &pw);
if (err)
{
if (gpg_err_code (err) == GPG_ERR_CANCELED
|| gpg_err_code (err) == GPG_ERR_FULLY_CANCELED)
log_info (_("cancelled\n"));
else
log_error (_("error while asking for the passphrase: %s\n"),
gpg_strerror (err));
agent_exit (0);
}
assert (pw);
return pw;
}
static void
release_passphrase (char *pw)
{
if (pw)
{
wipememory (pw, strlen (pw));
xfree (pw);
}
}
/* Stub function. */
gpg_error_t
convert_from_openpgp_native (gcry_sexp_t s_pgp, const char *passphrase,
unsigned char **r_key)
{
(void)s_pgp;
(void)passphrase;
(void)r_key;
return gpg_error (GPG_ERR_BUG);
}