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/* findkey.c - locate the secret key
* Copyright (C) 2001 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include <unistd.h>
#include <sys/stat.h>
#include "agent.h"
static int
unprotect (GCRY_SEXP s_skey)
{
struct pin_entry_info_s *pi;
int rc;
/* fixme: check whether the key needs unprotection */
/* fixme: allocate the pin in secure memory */
pi = xtrycalloc (1, sizeof (*pi) + 100);
pi->max_length = 100;
pi->min_digits = 4;
pi->max_digits = 8;
pi->max_tries = 3;
rc = agent_askpin (NULL, pi);
/* fixme: actually unprotect the key and ask again until we get a valid
PIN - agent_askpin takes care of counting failed tries */
xfree (pi);
return rc;
}
/* Return the secret key as an S-Exp after locating it using the grip. Returns NULL if key is not available. */
GCRY_SEXP
agent_key_from_file (const unsigned char *grip)
{
int i, rc;
char *fname;
FILE *fp;
struct stat st;
char *buf;
size_t buflen, erroff;
GCRY_SEXP s_skey;
char hexgrip[41];
for (i=0; i < 20; i++)
sprintf (hexgrip+2*i, "%02X", grip[i]);
hexgrip[40] = 0;
fname = make_filename (opt.homedir, "private-keys-v1.d", hexgrip, NULL );
fp = fopen (fname, "rb");
if (!fp)
{
log_error ("can't open `%s': %s\n", fname, strerror (errno));
xfree (fname);
return NULL;
}
if (fstat (fileno(fp), &st))
{
log_error ("can't stat `%s': %s\n", fname, strerror (errno));
xfree (fname);
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));
xfree (fname);
fclose (fp);
xfree (buf);
return NULL;
}
rc = gcry_sexp_sscan (&s_skey, &erroff, buf, buflen);
xfree (fname);
fclose (fp);
xfree (buf);
if (rc)
{
log_error ("failed to build S-Exp (off=%u): %s\n",
(unsigned int)erroff, gcry_strerror (rc));
return NULL;
}
rc = unprotect (s_skey);
if (rc)
{
gcry_sexp_release (s_skey);
log_error ("failed to unprotect the secret key: %s\n",
gcry_strerror (rc));
return NULL;
}
return s_skey;
}
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