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/*
This file is part of GNUnet.
Copyright (C) 2009-2013, 2016 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.
GNUnet 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
Affero General Public License for more details.
*/
/**
* @file credential/credential_misc.c
* @brief Misc API for credentials
*
* @author Martin Schanzenbach
*/
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_constants.h"
#include "gnunet_credential_service.h"
#include "gnunet_signatures.h"
#include "credential.h"
#include <inttypes.h>
char*
GNUNET_CREDENTIAL_credential_to_string (const struct GNUNET_CREDENTIAL_Credential *cred)
{
char *cred_str;
char *subject_pkey;
char *issuer_pkey;
char *signature;
subject_pkey = GNUNET_CRYPTO_ecdsa_public_key_to_string (&cred->subject_key);
issuer_pkey = GNUNET_CRYPTO_ecdsa_public_key_to_string (&cred->issuer_key);
GNUNET_STRINGS_base64_encode ((char*)&cred->signature,
sizeof (struct GNUNET_CRYPTO_EcdsaSignature),
&signature);
GNUNET_asprintf (&cred_str,
"%s.%s -> %s | %s | %"SCNu64,
issuer_pkey,
cred->issuer_attribute,
subject_pkey,
signature,
cred->expiration.abs_value_us);
GNUNET_free (subject_pkey);
GNUNET_free (issuer_pkey);
GNUNET_free (signature);
return cred_str;
}
struct GNUNET_CREDENTIAL_Credential*
GNUNET_CREDENTIAL_credential_from_string (const char* s)
{
struct GNUNET_CREDENTIAL_Credential *cred;
size_t enclen = (sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)) * 8;
if (enclen % 5 > 0)
enclen += 5 - enclen % 5;
enclen /= 5; /* 260/5 = 52 */
char subject_pkey[enclen + 1];
char issuer_pkey[enclen + 1];
char name[253 + 1];
char signature[256]; //TODO max payload size
struct GNUNET_CRYPTO_EcdsaSignature *sig;
struct GNUNET_TIME_Absolute etime_abs;
if (5 != SSCANF (s,
"%52s.%253s -> %52s | %s | %"SCNu64,
issuer_pkey,
name,
subject_pkey,
signature,
&etime_abs.abs_value_us))
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
_("Unable to parse CRED record string `%s'\n"),
s);
return NULL;
}
cred = GNUNET_malloc (sizeof (struct GNUNET_CREDENTIAL_Credential) + strlen (name) + 1);
GNUNET_CRYPTO_ecdsa_public_key_from_string (subject_pkey,
strlen (subject_pkey),
&cred->subject_key);
GNUNET_CRYPTO_ecdsa_public_key_from_string (issuer_pkey,
strlen (issuer_pkey),
&cred->issuer_key);
GNUNET_assert (sizeof (struct GNUNET_CRYPTO_EcdsaSignature) == GNUNET_STRINGS_base64_decode (signature,
strlen (signature),
(char**)&sig));
cred->signature = *sig;
cred->expiration = etime_abs;
GNUNET_free (sig);
GNUNET_memcpy (&cred[1],
name,
strlen (name)+1);
cred->issuer_attribute_len = strlen ((char*)&cred[1]);
cred->issuer_attribute = (char*)&cred[1];
return cred;
}
/**
* Issue an attribute to a subject
*
* @param issuer the ego that should be used to issue the attribute
* @param subject the subject of the attribute
* @param attribute the name of the attribute
* @return handle to the queued request
*/
struct GNUNET_CREDENTIAL_Credential *
GNUNET_CREDENTIAL_credential_issue (const struct GNUNET_CRYPTO_EcdsaPrivateKey *issuer,
struct GNUNET_CRYPTO_EcdsaPublicKey *subject,
const char *attribute,
struct GNUNET_TIME_Absolute *expiration)
{
struct CredentialEntry *crd;
struct GNUNET_CREDENTIAL_Credential *cred;
size_t size;
size = sizeof (struct CredentialEntry) + strlen (attribute) + 1;
crd = GNUNET_malloc (size);
cred = GNUNET_malloc (sizeof (struct GNUNET_CREDENTIAL_Credential) + strlen (attribute) + 1);
crd->purpose.size = htonl (size - sizeof (struct GNUNET_CRYPTO_EcdsaSignature));
crd->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_CREDENTIAL);
GNUNET_CRYPTO_ecdsa_key_get_public (issuer,
&crd->issuer_key);
crd->subject_key = *subject;
crd->expiration = GNUNET_htonll (expiration->abs_value_us);
crd->issuer_attribute_len = htonl (strlen (attribute)+1);
GNUNET_memcpy ((char*)&crd[1],
attribute,
strlen (attribute)+1);
if (GNUNET_OK !=
GNUNET_CRYPTO_ecdsa_sign (issuer,
&crd->purpose,
&crd->signature))
{
GNUNET_break (0);
GNUNET_free (crd);
GNUNET_free (cred);
return NULL;
}
cred->signature = crd->signature;
cred->expiration = *expiration;
GNUNET_CRYPTO_ecdsa_key_get_public (issuer,
&cred->issuer_key);
cred->subject_key = *subject;
GNUNET_memcpy (&cred[1],
attribute,
strlen (attribute)+1);
cred->issuer_attribute = (char*)&cred[1];
GNUNET_free (crd);
return cred;
}
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