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/* pksign.c - public key signing (well, actually using a secret key)
* Copyright (C) 2001, 2002, 2003, 2004 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
do_encode_md (const byte * md, size_t mdlen, int algo, gcry_sexp_t * r_hash)
{
gcry_sexp_t hash;
const char *s;
char tmp[16+1];
int i, rc;
s = gcry_md_algo_name (algo);
if (s && strlen (s) < 16)
{
for (i=0; i < strlen (s); i++)
tmp[i] = tolower (s[i]);
tmp[i] = '\0';
}
rc = gcry_sexp_build (&hash, NULL,
"(data (flags pkcs1) (hash %s %b))",
tmp,
mdlen, md);
*r_hash = hash;
return rc;
}
/* SIGN whatever information we have accumulated in CTRL and write it
back to OUTFP. */
int
agent_pksign (CTRL ctrl, const char *desc_text, FILE *outfp, int ignore_cache)
{
gcry_sexp_t s_skey = NULL, s_hash = NULL, s_sig = NULL;
unsigned char *shadow_info = NULL;
int rc;
char *buf = NULL;
size_t len;
if (!ctrl->have_keygrip)
return gpg_error (GPG_ERR_NO_SECKEY);
rc = agent_key_from_file (ctrl, desc_text, ctrl->keygrip,
&shadow_info, ignore_cache, &s_skey);
if (rc)
{
log_error ("failed to read the secret key\n");
goto leave;
}
if (!s_skey)
{ /* divert operation to the smartcard */
unsigned char *sigbuf;
rc = divert_pksign (ctrl,
ctrl->digest.value,
ctrl->digest.valuelen,
ctrl->digest.algo,
shadow_info, &sigbuf);
if (rc)
{
log_error ("smartcard signing failed: %s\n", gpg_strerror (rc));
goto leave;
}
len = gcry_sexp_canon_len (sigbuf, 0, NULL, NULL);
assert (len);
buf = sigbuf;
}
else
{ /* no smartcard, but a private key */
/* put the hash into a sexp */
rc = do_encode_md (ctrl->digest.value,
ctrl->digest.valuelen,
ctrl->digest.algo,
&s_hash);
if (rc)
goto leave;
if (DBG_CRYPTO)
{
log_debug ("skey: ");
gcry_sexp_dump (s_skey);
}
/* sign */
rc = gcry_pk_sign (&s_sig, s_hash, s_skey);
if (rc)
{
log_error ("signing failed: %s\n", gpg_strerror (rc));
goto leave;
}
if (DBG_CRYPTO)
{
log_debug ("result: ");
gcry_sexp_dump (s_sig);
}
len = gcry_sexp_sprint (s_sig, GCRYSEXP_FMT_CANON, NULL, 0);
assert (len);
buf = xmalloc (len);
len = gcry_sexp_sprint (s_sig, GCRYSEXP_FMT_CANON, buf, len);
assert (len);
}
/* FIXME: we must make sure that no buffering takes place or we are
in full control of the buffer memory (easy to do) - should go
into assuan. */
fwrite (buf, 1, len, outfp);
leave:
gcry_sexp_release (s_skey);
gcry_sexp_release (s_hash);
gcry_sexp_release (s_sig);
xfree (buf);
xfree (shadow_info);
return rc;
}
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