Page MenuHome GnuPG
Files F18824686

fingerprint.c
No OneTemporary
Actions

fingerprint.c
View Options

/* fingerprint.c - Get the fingerprint
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <assert.h>
#include "gpgsm.h"
#include <gcrypt.h>
#include <ksba.h>
/* Return the fingerprint of the certificate (we can't put this into
libksba because we need libgcrypt support). The caller must
provide an array of sufficient length or NULL so that the function
allocates the array. If r_len is not NULL, the length of the
digest is returned; well, this can also be done by using
gcry_md_get_algo_dlen(). If algo is 0, a SHA-1 will be used.
If there is a problem , the function does never return NULL but a
digest of all 0xff.
*/
unsigned char *
gpgsm_get_fingerprint (ksba_cert_t cert, int algo,
unsigned char *array, int *r_len)
{
gcry_md_hd_t md;
int rc, len;
if (!algo)
algo = GCRY_MD_SHA1;
len = gcry_md_get_algo_dlen (algo);
assert (len);
if (!array)
array = xmalloc (len);
if (r_len)
*r_len = len;
rc = gcry_md_open (&md, algo, 0);
if (rc)
{
log_error ("md_open failed: %s\n", gpg_strerror (rc));
memset (array, 0xff, len); /* better return an invalid fpr than NULL */
return array;
}
rc = ksba_cert_hash (cert, 0, HASH_FNC, md);
if (rc)
{
log_error ("ksba_cert_hash failed: %s\n", gpg_strerror (rc));
gcry_md_close (md);
memset (array, 0xff, len); /* better return an invalid fpr than NULL */
return array;
}
gcry_md_final (md);
memcpy (array, gcry_md_read(md, algo), len );
return array;
}
/* Return an allocated buffer with the formatted fingerprint */
char *
gpgsm_get_fingerprint_string (ksba_cert_t cert, int algo)
{
unsigned char digest[MAX_DIGEST_LEN];
char *buf;
int len, i;
if (!algo)
algo = GCRY_MD_SHA1;
len = gcry_md_get_algo_dlen (algo);
assert (len <= MAX_DIGEST_LEN );
gpgsm_get_fingerprint (cert, algo, digest, NULL);
buf = xmalloc (len*3+1);
*buf = 0;
for (i=0; i < len; i++ )
sprintf (buf+strlen(buf), i? ":%02X":"%02X", digest[i]);
return buf;
}
/* Return an allocated buffer with the formatted fingerprint as one
large hexnumber */
char *
gpgsm_get_fingerprint_hexstring (ksba_cert_t cert, int algo)
{
unsigned char digest[MAX_DIGEST_LEN];
char *buf;
int len, i;
if (!algo)
algo = GCRY_MD_SHA1;
len = gcry_md_get_algo_dlen (algo);
assert (len <= MAX_DIGEST_LEN );
gpgsm_get_fingerprint (cert, algo, digest, NULL);
buf = xmalloc (len*3+1);
*buf = 0;
for (i=0; i < len; i++ )
sprintf (buf+strlen(buf), "%02X", digest[i]);
return buf;
}
/* Return a certificate ID. These are the last 4 bytes of the SHA-1
fingerprint. */
unsigned long
gpgsm_get_short_fingerprint (ksba_cert_t cert)
{
unsigned char digest[20];
gpgsm_get_fingerprint (cert, GCRY_MD_SHA1, digest, NULL);
return ((digest[16]<<24)|(digest[17]<<16)|(digest[18]<< 8)|digest[19]);
}
/* Return the so called KEYGRIP which is the SHA-1 hash of the public
key parameters expressed as an canoncial encoded S-Exp. array must
be 20 bytes long. returns the array or a newly allocated one if the
passed one was NULL */
unsigned char *
gpgsm_get_keygrip (ksba_cert_t cert, unsigned char *array)
{
gcry_sexp_t s_pkey;
int rc;
ksba_sexp_t p;
size_t n;
p = ksba_cert_get_public_key (cert);
if (!p)
return NULL; /* oops */
if (DBG_X509)
log_debug ("get_keygrip for public key\n");
n = gcry_sexp_canon_len (p, 0, NULL, NULL);
if (!n)
{
log_error ("libksba did not return a proper S-Exp\n");
return NULL;
}
rc = gcry_sexp_sscan ( &s_pkey, NULL, (char*)p, n);
xfree (p);
if (rc)
{
log_error ("gcry_sexp_scan failed: %s\n", gpg_strerror (rc));
return NULL;
}
array = gcry_pk_get_keygrip (s_pkey, array);
gcry_sexp_release (s_pkey);
if (!array)
{
rc = gpg_error (GPG_ERR_GENERAL);
log_error ("can't calculate keygrip\n");
return NULL;
}
if (DBG_X509)
log_printhex ("keygrip=", array, 20);
return array;
}
/* Return an allocated buffer with the keygrip of CERT in from of an
hexstring. NULL is returned in case of error */
char *
gpgsm_get_keygrip_hexstring (ksba_cert_t cert)
{
unsigned char grip[20];
char *buf, *p;
int i;
gpgsm_get_keygrip (cert, grip);
buf = p = xmalloc (20*2+1);
for (i=0; i < 20; i++, p += 2 )
sprintf (p, "%02X", grip[i]);
return buf;
}
/* Return the PK algorithm used by CERT as well as the length in bits
of the public key at NBITS. */
int
gpgsm_get_key_algo_info (ksba_cert_t cert, unsigned int *nbits)
{
gcry_sexp_t s_pkey;
int rc;
ksba_sexp_t p;
size_t n;
gcry_sexp_t l1, l2;
const char *name;
char namebuf[128];
if (nbits)
*nbits = 0;
p = ksba_cert_get_public_key (cert);
if (!p)
return 0;
n = gcry_sexp_canon_len (p, 0, NULL, NULL);
if (!n)
{
xfree (p);
return 0;
}
rc = gcry_sexp_sscan (&s_pkey, NULL, (char *)p, n);
xfree (p);
if (rc)
return 0;
if (nbits)
*nbits = gcry_pk_get_nbits (s_pkey);
/* Breaking the algorithm out of the S-exp is a bit of a challenge ... */
l1 = gcry_sexp_find_token (s_pkey, "public-key", 0);
if (!l1)
{
gcry_sexp_release (s_pkey);
return 0;
}
l2 = gcry_sexp_cadr (l1);
gcry_sexp_release (l1);
l1 = l2;
name = gcry_sexp_nth_data (l1, 0, &n);
if (name)
{
if (n > sizeof namebuf -1)
n = sizeof namebuf -1;
memcpy (namebuf, name, n);
namebuf[n] = 0;
}
else
*namebuf = 0;
gcry_sexp_release (l1);
gcry_sexp_release (s_pkey);
return gcry_pk_map_name (namebuf);
}
/* For certain purposes we need a certificate id which has an upper
limit of the size. We use the hash of the issuer name and the
serial number for this. In most cases the serial number is not
that large and the resulting string can be passed on an assuan
command line. Everything is hexencoded with the serialnumber
delimited from the hash by a dot.
The caller must free the string.
*/
char *
gpgsm_get_certid (ksba_cert_t cert)
{
ksba_sexp_t serial;
char *p;
char *endp;
unsigned char hash[20];
unsigned long n;
char *certid;
int i;
p = ksba_cert_get_issuer (cert, 0);
if (!p)
return NULL; /* Ooops: No issuer */
gcry_md_hash_buffer (GCRY_MD_SHA1, hash, p, strlen (p));
xfree (p);
serial = ksba_cert_get_serial (cert);
if (!serial)
return NULL; /* oops: no serial number */
p = (char *)serial;
if (*p != '(')
{
log_error ("Ooops: invalid serial number\n");
xfree (serial);
return NULL;
}
p++;
n = strtoul (p, &endp, 10);
p = endp;
if (*p != ':')
{
log_error ("Ooops: invalid serial number (no colon)\n");
xfree (serial);
return NULL;
}
p++;
certid = xtrymalloc ( 40 + 1 + n*2 + 1);
if (!certid)
{
xfree (serial);
return NULL; /* out of core */
}
for (i=0, endp = certid; i < 20; i++, endp += 2 )
sprintf (endp, "%02X", hash[i]);
*endp++ = '.';
for (i=0; i < n; i++, endp += 2)
sprintf (endp, "%02X", ((unsigned char*)p)[i]);
*endp = 0;
xfree (serial);
return certid;
}

File Metadata

Mime Type
text/x-c
Expires
Mon, Dec 23, 1:08 PM (24 m, 17 s)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
76/e7/b7888c651bd24064f0f40abbf51e

Event Timeline