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/*
This file is part of TALER
Copyright (C) 2014-2017 Inria & GNUnet e.V.
TALER 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, or (at your option) any later version.
TALER 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
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file exchangedb/exchangedb_denomkeys.c
* @brief I/O operations for the Exchange's denomination private keys
* @author Florian Dold
* @author Benedikt Mueller
* @author Sree Harsha Totakura
* @author Christian Grothoff
*/
#include "platform.h"
#include "taler_exchangedb_lib.h"
/**
* Mark the given denomination key as revoked and request the wallets
* to initiate /payback.
*
* @param exchange_base_dir base directory for the exchange,
* the signing keys must be in the #TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS
* subdirectory
* @param alias coin alias
* @param dki the denomination key to revoke
* @param mpriv master private key to sign
* @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure.
*/
int
TALER_EXCHANGEDB_denomination_key_revoke (const char *exchange_base_dir,
const char *alias,
const struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki,
const struct TALER_MasterPrivateKeyP *mpriv)
{
struct GNUNET_TIME_Absolute start;
struct TALER_MasterDenominationKeyRevocation rm;
struct TALER_MasterSignatureP msig;
char *fn;
struct GNUNET_DISK_FileHandle *fh;
ssize_t wrote;
int ret;
ret = GNUNET_SYSERR;
start = GNUNET_TIME_absolute_ntoh (dki->issue.properties.start);
GNUNET_asprintf (&fn,
"%s" DIR_SEPARATOR_STR "%s" DIR_SEPARATOR_STR "%llu.rev",
exchange_base_dir,
alias,
(unsigned long long) start.abs_value_us);
rm.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED);
rm.purpose.size = htonl (sizeof (rm));
rm.h_denom_pub = dki->issue.properties.denom_hash;
GNUNET_assert (GNUNET_OK ==
GNUNET_CRYPTO_eddsa_sign (&mpriv->eddsa_priv,
&rm.purpose,
&msig.eddsa_signature));
if (NULL == (fh = GNUNET_DISK_file_open
(fn,
GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_CREATE | GNUNET_DISK_OPEN_TRUNCATE,
GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE)))
goto cleanup;
if (GNUNET_SYSERR ==
(wrote = GNUNET_DISK_file_write (fh,
&msig,
sizeof (msig))))
goto cleanup;
if (wrote != sizeof (msig))
goto cleanup;
ret = GNUNET_OK;
cleanup:
if (NULL != fh)
(void) GNUNET_DISK_file_close (fh);
GNUNET_free (fn);
return ret;
}
/**
* Import a denomination key from the given file.
*
* @param filename the file to import the key from
* @param[out] dki set to the imported denomination key
* @return #GNUNET_OK upon success;
* #GNUNET_SYSERR upon failure
*/
int
TALER_EXCHANGEDB_denomination_key_read (const char *filename,
struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki)
{
uint64_t size;
size_t offset;
void *data;
struct GNUNET_CRYPTO_RsaPrivateKey *priv;
if (GNUNET_OK !=
GNUNET_DISK_file_size (filename,
&size,
GNUNET_YES,
GNUNET_YES))
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Skipping inaccessable denomination key file `%s'\n",
filename);
return GNUNET_SYSERR;
}
offset = sizeof (struct TALER_EXCHANGEDB_DenominationKeyInformationP);
if (size <= offset)
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
data = GNUNET_malloc (size);
if (size !=
GNUNET_DISK_fn_read (filename,
data,
size))
{
GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
"read",
filename);
GNUNET_free (data);
return GNUNET_SYSERR;
}
if (NULL ==
(priv = GNUNET_CRYPTO_rsa_private_key_decode (data + offset,
size - offset)))
{
GNUNET_free (data);
return GNUNET_SYSERR;
}
GNUNET_assert (NULL == dki->denom_priv.rsa_private_key);
dki->denom_priv.rsa_private_key = priv;
dki->denom_pub.rsa_public_key
= GNUNET_CRYPTO_rsa_private_key_get_public (priv);
memcpy (&dki->issue,
data,
offset);
GNUNET_free (data);
return GNUNET_OK;
}
/**
* Exports a denomination key to the given file.
*
* @param filename the file where to write the denomination key
* @param dki the denomination key
* @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure.
*/
int
TALER_EXCHANGEDB_denomination_key_write (const char *filename,
const struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki)
{
char *priv_enc;
size_t priv_enc_size;
struct GNUNET_DISK_FileHandle *fh;
ssize_t wrote;
size_t wsize;
int ret;
fh = NULL;
priv_enc_size
= GNUNET_CRYPTO_rsa_private_key_encode (dki->denom_priv.rsa_private_key,
&priv_enc);
ret = GNUNET_SYSERR;
if (GNUNET_OK !=
GNUNET_DISK_directory_create_for_file (filename))
return GNUNET_SYSERR;
if (NULL == (fh = GNUNET_DISK_file_open
(filename,
GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_CREATE | GNUNET_DISK_OPEN_TRUNCATE,
GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE)))
goto cleanup;
wsize = sizeof (struct TALER_EXCHANGEDB_DenominationKeyInformationP);
if (GNUNET_SYSERR == (wrote = GNUNET_DISK_file_write (fh,
&dki->issue,
wsize)))
goto cleanup;
if (wrote != wsize)
goto cleanup;
if (GNUNET_SYSERR ==
(wrote = GNUNET_DISK_file_write (fh,
priv_enc,
priv_enc_size)))
goto cleanup;
if (wrote != priv_enc_size)
goto cleanup;
ret = GNUNET_OK;
cleanup:
GNUNET_free_non_null (priv_enc);
if (NULL != fh)
(void) GNUNET_DISK_file_close (fh);
return ret;
}
/**
* Closure for #denomkeys_iterate_keydir_iter() and
* #denomkeys_iterate_topdir_iter().
*/
struct DenomkeysIterateContext
{
/**
* Set to the name of the directory below the top-level directory
* during the call to #denomkeys_iterate_keydir_iter().
*/
const char *alias;
/**
* Master public key to use to validate revocations.
*/
const struct TALER_MasterPublicKeyP *master_pub;
/**
* Function to call on each denomination key.
*/
TALER_EXCHANGEDB_DenominationKeyIterator it;
/**
* Closure for @e it.
*/
void *it_cls;
};
/**
* Decode the denomination key in the given file @a filename and call
* the callback in @a cls with the information.
*
* @param cls the `struct DenomkeysIterateContext *`
* @param filename name of a file that should contain
* a denomination key
* @return #GNUNET_OK to continue to iterate
* #GNUNET_NO to abort iteration with success
* #GNUNET_SYSERR to abort iteration with failure
*/
static int
denomkeys_iterate_keydir_iter (void *cls,
const char *filename)
{
struct DenomkeysIterateContext *dic = cls;
struct TALER_EXCHANGEDB_DenominationKeyIssueInformation issue;
int ret;
char *rev;
struct TALER_MasterSignatureP msig;
struct TALER_MasterDenominationKeyRevocation rm;
const struct TALER_MasterSignatureP *revoked;
if ( (strlen(filename) > strlen (".rev")) &&
(0 == strcmp (&filename[strlen(filename) - strlen (".rev")],
".rev")) )
return GNUNET_OK; /* ignore revocation files _here_; we'll try for them just below */
memset (&issue, 0, sizeof (issue));
if (GNUNET_OK !=
TALER_EXCHANGEDB_denomination_key_read (filename,
&issue))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"Invalid denomkey file: '%s'\n",
filename);
return GNUNET_OK;
}
/* check for revocation file */
GNUNET_asprintf (&rev,
"%s.rev",
filename);
revoked = NULL;
if (GNUNET_YES == GNUNET_DISK_file_test (rev))
{
/* Check if revocation is valid... */
if (sizeof (msig) !=
GNUNET_DISK_fn_read (rev,
&msig,
sizeof (msig)))
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
_("Invalid revocation file `%s' found and ignored (bad size)\n"),
rev);
}
else
{
rm.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED);
rm.purpose.size = htonl (sizeof (rm));
rm.h_denom_pub = issue.issue.properties.denom_hash;
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_REVOKED,
&rm.purpose,
&msig.eddsa_signature,
&dic->master_pub->eddsa_pub))
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
_("Invalid revocation file `%s' found and ignored (bad signature)\n"),
rev);
}
else
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Denomination key `%s' was revoked!\n",
filename);
revoked = &msig;
}
}
}
GNUNET_free (rev);
ret = dic->it (dic->it_cls,
dic->alias,
&issue,
revoked);
GNUNET_CRYPTO_rsa_private_key_free (issue.denom_priv.rsa_private_key);
GNUNET_CRYPTO_rsa_public_key_free (issue.denom_pub.rsa_public_key);
return ret;
}
/**
* Function called on each subdirectory in the #TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS. Will
* call the #denomkeys_iterate_keydir_iter() on each file in the
* subdirectory.
*
* @param cls the `struct DenomkeysIterateContext *`
* @param filename name of the subdirectory to scan
* @return #GNUNET_OK on success,
* #GNUNET_SYSERR if we need to abort
*/
static int
denomkeys_iterate_topdir_iter (void *cls,
const char *filename)
{
struct DenomkeysIterateContext *dic = cls;
dic->alias = GNUNET_STRINGS_get_short_name (filename);
if (0 > GNUNET_DISK_directory_scan (filename,
&denomkeys_iterate_keydir_iter,
dic))
return GNUNET_SYSERR;
return GNUNET_OK;
}
/**
* Call @a it for each denomination key found in the @a exchange_base_dir.
*
* @param exchange_base_dir base directory for the exchange,
* the signing keys must be in the #TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS
* subdirectory
* @param master_pub master public key (used to check revocations)
* @param it function to call on each denomination key found
* @param it_cls closure for @a it
* @return -1 on error, 0 if no files were found, otherwise
* a positive number (however, even with a positive
* number it is possible that @a it was never called
* as maybe none of the files were well-formed)
*/
int
TALER_EXCHANGEDB_denomination_keys_iterate (const char *exchange_base_dir,
const struct TALER_MasterPublicKeyP *master_pub,
TALER_EXCHANGEDB_DenominationKeyIterator it,
void *it_cls)
{
char *dir;
struct DenomkeysIterateContext dic;
int ret;
GNUNET_asprintf (&dir,
"%s" DIR_SEPARATOR_STR TALER_EXCHANGEDB_DIR_DENOMINATION_KEYS,
exchange_base_dir);
dic.master_pub = master_pub;
dic.it = it;
dic.it_cls = it_cls;
ret = GNUNET_DISK_directory_scan (dir,
&denomkeys_iterate_topdir_iter,
&dic);
GNUNET_free (dir);
return ret;
}
/* end of exchangedb_denomkeys.c */
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