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/* Loading of PEM encoded files with optional encryption
* Copyright (C) 2001-2009 Andreas Steffen
* HSR Hochschule fuer Technik Rapperswil
*
* This program 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 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program 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.
*/
/* decrypt a PEM encoded data block using DES-EDE3-CBC
* see RFC 1423 PEM: Algorithms, Modes and Identifiers
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stddef.h>
#include <sys/types.h>
#include <freeswan.h>
#include <library.h>
#include <asn1/pem.h>
#include "constants.h"
#include "defs.h"
#include "log.h"
#include "whack.h"
#include "pem.h"
/**
* Converts a PEM encoded file into its binary form
* RFC 1421 Privacy Enhancement for Electronic Mail, February 1993
* RFC 934 Message Encapsulation, January 1985
*/
err_t pemtobin(chunk_t *blob, prompt_pass_t *pass, const char* label, bool *pgp)
{
chunk_t password = chunk_empty;
/* do we prompt for the passphrase? */
if (pass && pass->prompt && pass->fd != NULL_FD)
{
int i;
chunk_t blob_copy;
err_t ugh = "invalid passphrase, too many trials";
status_t status;
whack_log(RC_ENTERSECRET, "need passphrase for '%s'", label);
for (i = 0; i < MAX_PROMPT_PASS_TRIALS; i++)
{
int n;
if (i > 0)
{
whack_log(RC_ENTERSECRET, "invalid passphrase, please try again");
}
n = read(pass->fd, pass->secret, PROMPT_PASS_LEN);
if (n == -1)
{
err_t ugh = "read(whackfd) failed";
whack_log(RC_LOG_SERIOUS,ugh);
return ugh;
}
pass->secret[n-1] = '\0';
if (strlen(pass->secret) == 0)
{
err_t ugh = "no passphrase entered, aborted";
whack_log(RC_LOG_SERIOUS, ugh);
return ugh;
}
blob_copy = chunk_clone(*blob);
password = chunk_create(pass->secret, strlen(pass->secret));
status = pem_to_bin(blob, password, pgp);
if (status != INVALID_ARG)
{
if (status == SUCCESS)
{
whack_log(RC_SUCCESS, "valid passphrase");
}
else
{
whack_log(RC_LOG_SERIOUS, "%N, aborted", status_names, status);
}
free(blob_copy.ptr);
return NULL;
}
/* blob is useless after wrong decryption, restore the original */
free(blob->ptr);
*blob = blob_copy;
}
whack_log(RC_LOG_SERIOUS, ugh);
return ugh;
}
else
{
if (pass)
{
password = chunk_create(pass->secret, strlen(pass->secret));
}
if (pem_to_bin(blob, password, pgp) == SUCCESS)
{
return NULL;
}
else
{
return "pem to bin conversion failed";
}
}
}
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