security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2024-12-22 10:19:57 +01:00
Code Activity
gnupg/sm/sign.c
Werner Koch b008274afd Nuked almost all trailing white space. 
We better do this once and for all instead of cluttering all future
commits with diffs of trailing white spaces.  In the majority of cases
blank or single lines are affected and thus this change won't disturb
a git blame too much.  For future commits the pre-commit scripts
checks that this won't happen again.
2011-02-04 12:57:53 +01:00

786 lines
21 KiB
C
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* sign.c - Sign a message
* Copyright (C) 2001, 2002, 2003, 2008,
* 2010 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#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>
#include "keydb.h"
#include "i18n.h"
/* Hash the data and return if something was hashed. Return -1 on error. */
static int
hash_data (int fd, gcry_md_hd_t md)
{
estream_t fp;
char buffer[4096];
int nread;
int rc = 0;
fp = es_fdopen_nc (fd, "rb");
if (!fp)
{
log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
return -1;
}
do
{
nread = es_fread (buffer, 1, DIM(buffer), fp);
gcry_md_write (md, buffer, nread);
}
while (nread);
if (es_ferror (fp))
{
log_error ("read error on fd %d: %s\n", fd, strerror (errno));
rc = -1;
}
es_fclose (fp);
return rc;
}
static int
hash_and_copy_data (int fd, gcry_md_hd_t md, ksba_writer_t writer)
{
gpg_error_t err;
estream_t fp;
char buffer[4096];
int nread;
int rc = 0;
int any = 0;
fp = es_fdopen_nc (fd, "rb");
if (!fp)
{
gpg_error_t tmperr = gpg_error_from_syserror ();
log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
return tmperr;
}
do
{
nread = es_fread (buffer, 1, DIM(buffer), fp);
if (nread)
{
any = 1;
gcry_md_write (md, buffer, nread);
err = ksba_writer_write_octet_string (writer, buffer, nread, 0);
if (err)
{
log_error ("write failed: %s\n", gpg_strerror (err));
rc = err;
}
}
}
while (nread && !rc);
if (es_ferror (fp))
{
rc = gpg_error_from_syserror ();
log_error ("read error on fd %d: %s\n", fd, strerror (errno));
}
es_fclose (fp);
if (!any)
{
/* We can't allow to sign an empty message because it does not
make much sense and more seriously, ksba_cms_build has
already written the tag for data and now expects an octet
string and an octet string of size 0 is illegal. */
log_error ("cannot sign an empty message\n");
rc = gpg_error (GPG_ERR_NO_DATA);
}
if (!rc)
{
err = ksba_writer_write_octet_string (writer, NULL, 0, 1);
if (err)
{
log_error ("write failed: %s\n", gpg_strerror (err));
rc = err;
}
}
return rc;
}
/* Get the default certificate which is defined as the first
certificate capable of signing returned by the keyDB and has a
secret key available. */
int
gpgsm_get_default_cert (ctrl_t ctrl, ksba_cert_t *r_cert)
{
KEYDB_HANDLE hd;
ksba_cert_t cert = NULL;
int rc;
char *p;
hd = keydb_new (0);
if (!hd)
return gpg_error (GPG_ERR_GENERAL);
rc = keydb_search_first (hd);
if (rc)
{
keydb_release (hd);
return rc;
}
do
{
rc = keydb_get_cert (hd, &cert);
if (rc)
{
log_error ("keydb_get_cert failed: %s\n", gpg_strerror (rc));
keydb_release (hd);
return rc;
}
if (!gpgsm_cert_use_sign_p (cert))
{
p = gpgsm_get_keygrip_hexstring (cert);
if (p)
{
if (!gpgsm_agent_havekey (ctrl, p))
{
xfree (p);
keydb_release (hd);
*r_cert = cert;
return 0; /* got it */
}
xfree (p);
}
}
ksba_cert_release (cert);
cert = NULL;
}
while (!(rc = keydb_search_next (hd)));
if (rc && rc != -1)
log_error ("keydb_search_next failed: %s\n", gpg_strerror (rc));
ksba_cert_release (cert);
keydb_release (hd);
return rc;
}
static ksba_cert_t
get_default_signer (ctrl_t ctrl)
{
KEYDB_SEARCH_DESC desc;
ksba_cert_t cert = NULL;
KEYDB_HANDLE kh = NULL;
int rc;
if (!opt.local_user)
{
rc = gpgsm_get_default_cert (ctrl, &cert);
if (rc)
{
if (rc != -1)
log_debug ("failed to find default certificate: %s\n",
gpg_strerror (rc));
return NULL;
}
return cert;
}
rc = classify_user_id (opt.local_user, &desc);
if (rc)
{
log_error ("failed to find default signer: %s\n", gpg_strerror (rc));
return NULL;
}
kh = keydb_new (0);
if (!kh)
return NULL;
rc = keydb_search (kh, &desc, 1);
if (rc)
{
log_debug ("failed to find default certificate: rc=%d\n", rc);
}
else
{
rc = keydb_get_cert (kh, &cert);
if (rc)
{
log_debug ("failed to get cert: rc=%d\n", rc);
}
}
keydb_release (kh);
return cert;
}
/* Depending on the options in CTRL add the certificate CERT as well as
other certificate up in the chain to the Root-CA to the CMS
object. */
static int
add_certificate_list (ctrl_t ctrl, ksba_cms_t cms, ksba_cert_t cert)
{
gpg_error_t err;
int rc = 0;
ksba_cert_t next = NULL;
int n;
int not_root = 0;
ksba_cert_ref (cert);
n = ctrl->include_certs;
log_debug ("adding certificates at level %d\n", n);
if (n == -2)
{
not_root = 1;
n = -1;
}
if (n < 0 || n > 50)
n = 50; /* We better apply an upper bound */
/* First add my own certificate unless we don't want any certificate
included at all. */
if (n)
{
if (not_root && gpgsm_is_root_cert (cert))
err = 0;
else
err = ksba_cms_add_cert (cms, cert);
if (err)
goto ksba_failure;
if (n>0)
n--;
}
/* Walk the chain to include all other certificates. Note that a -1
used for N makes sure that there is no limit and all certs get
included. */
while ( n-- && !(rc = gpgsm_walk_cert_chain (ctrl, cert, &next)) )
{
if (not_root && gpgsm_is_root_cert (next))
err = 0;
else
err = ksba_cms_add_cert (cms, next);
ksba_cert_release (cert);
cert = next; next = NULL;
if (err)
goto ksba_failure;
}
ksba_cert_release (cert);
return rc == -1? 0: rc;
ksba_failure:
ksba_cert_release (cert);
log_error ("ksba_cms_add_cert failed: %s\n", gpg_strerror (err));
return err;
}
/* Perform a sign operation.
Sign the data received on DATA-FD in embedded mode or in detached
mode when DETACHED is true. Write the signature to OUT_FP. The
keys used to sign are taken from SIGNERLIST or the default one will
be used if the value of this argument is NULL. */
int
gpgsm_sign (ctrl_t ctrl, certlist_t signerlist,
int data_fd, int detached, estream_t out_fp)
{
int i, rc;
gpg_error_t err;
Base64Context b64writer = NULL;
ksba_writer_t writer;
ksba_cms_t cms = NULL;
ksba_stop_reason_t stopreason;
KEYDB_HANDLE kh = NULL;
gcry_md_hd_t data_md = NULL;
int signer;
const char *algoid;
int algo;
ksba_isotime_t signed_at;
certlist_t cl;
int release_signerlist = 0;
audit_set_type (ctrl->audit, AUDIT_TYPE_SIGN);
kh = keydb_new (0);
if (!kh)
{
log_error (_("failed to allocated keyDB handle\n"));
rc = gpg_error (GPG_ERR_GENERAL);
goto leave;
}
ctrl->pem_name = "SIGNED MESSAGE";
rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, &writer);
if (rc)
{
log_error ("can't create writer: %s\n", gpg_strerror (rc));
goto leave;
}
err = ksba_cms_new (&cms);
if (err)
{
rc = err;
goto leave;
}
err = ksba_cms_set_reader_writer (cms, NULL, writer);
if (err)
{
log_debug ("ksba_cms_set_reader_writer failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
/* We are going to create signed data with data as encap. content */
err = ksba_cms_set_content_type (cms, 0, KSBA_CT_SIGNED_DATA);
if (!err)
err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
if (err)
{
log_debug ("ksba_cms_set_content_type failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
/* If no list of signers is given, use the default certificate. */
if (!signerlist)
{
ksba_cert_t cert = get_default_signer (ctrl);
if (!cert)
{
log_error ("no default signer found\n");
gpgsm_status2 (ctrl, STATUS_INV_SGNR,
get_inv_recpsgnr_code (GPG_ERR_NO_SECKEY), NULL);
rc = gpg_error (GPG_ERR_GENERAL);
goto leave;
}
/* Although we don't check for ambigious specification we will
check that the signer's certificate is usable and valid. */
rc = gpgsm_cert_use_sign_p (cert);
if (!rc)
rc = gpgsm_validate_chain (ctrl, cert, "", NULL, 0, NULL, 0, NULL);
if (rc)
{
char *tmpfpr;
tmpfpr = gpgsm_get_fingerprint_hexstring (cert, 0);
gpgsm_status2 (ctrl, STATUS_INV_SGNR,
get_inv_recpsgnr_code (rc), tmpfpr, NULL);
xfree (tmpfpr);
goto leave;
}
/* That one is fine - create signerlist. */
signerlist = xtrycalloc (1, sizeof *signerlist);
if (!signerlist)
{
rc = out_of_core ();
ksba_cert_release (cert);
goto leave;
}
signerlist->cert = cert;
release_signerlist = 1;
}
/* Figure out the hash algorithm to use. We do not want to use the
one for the certificate but if possible an OID for the plain
algorithm. */
if (opt.forced_digest_algo && opt.verbose)
log_info ("user requested hash algorithm %d\n", opt.forced_digest_algo);
for (i=0, cl=signerlist; cl; cl = cl->next, i++)
{
const char *oid;
if (opt.forced_digest_algo)
{
oid = NULL;
cl->hash_algo = opt.forced_digest_algo;
}
else
{
oid = ksba_cert_get_digest_algo (cl->cert);
cl->hash_algo = oid ? gcry_md_map_name (oid) : 0;
}
switch (cl->hash_algo)
{
case GCRY_MD_SHA1: oid = "1.3.14.3.2.26"; break;
case GCRY_MD_RMD160: oid = "1.3.36.3.2.1"; break;
case GCRY_MD_SHA224: oid = "2.16.840.1.101.3.4.2.4"; break;
case GCRY_MD_SHA256: oid = "2.16.840.1.101.3.4.2.1"; break;
case GCRY_MD_SHA384: oid = "2.16.840.1.101.3.4.2.2"; break;
case GCRY_MD_SHA512: oid = "2.16.840.1.101.3.4.2.3"; break;
/* case GCRY_MD_WHIRLPOOL: oid = "No OID yet"; break; */
case GCRY_MD_MD5: /* We don't want to use MD5. */
case 0: /* No algorithm found in cert. */
default: /* Other algorithms. */
log_info (_("hash algorithm %d (%s) for signer %d not supported;"
" using %s\n"),
cl->hash_algo, oid? oid: "?", i,
gcry_md_algo_name (GCRY_MD_SHA1));
cl->hash_algo = GCRY_MD_SHA1;
oid = "1.3.14.3.2.26";
break;
}
cl->hash_algo_oid = oid;
}
if (opt.verbose)
{
for (i=0, cl=signerlist; cl; cl = cl->next, i++)
log_info (_("hash algorithm used for signer %d: %s (%s)\n"),
i, gcry_md_algo_name (cl->hash_algo), cl->hash_algo_oid);
}
/* Gather certificates of signers and store them in the CMS object. */
for (cl=signerlist; cl; cl = cl->next)
{
rc = gpgsm_cert_use_sign_p (cl->cert);
if (rc)
goto leave;
err = ksba_cms_add_signer (cms, cl->cert);
if (err)
{
log_error ("ksba_cms_add_signer failed: %s\n", gpg_strerror (err));
rc = err;
goto leave;
}
rc = add_certificate_list (ctrl, cms, cl->cert);
if (rc)
{
log_error ("failed to store list of certificates: %s\n",
gpg_strerror(rc));
goto leave;
}
/* Set the hash algorithm we are going to use */
err = ksba_cms_add_digest_algo (cms, cl->hash_algo_oid);
if (err)
{
log_debug ("ksba_cms_add_digest_algo failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
}
/* Check whether one of the certificates is qualified. Note that we
already validated the certificate and thus the user data stored
flag must be available. */
if (!opt.no_chain_validation)
{
for (cl=signerlist; cl; cl = cl->next)
{
size_t buflen;
char buffer[1];
err = ksba_cert_get_user_data (cl->cert, "is_qualified",
&buffer, sizeof (buffer), &buflen);
if (err || !buflen)
{
log_error (_("checking for qualified certificate failed: %s\n"),
gpg_strerror (err));
rc = err;
goto leave;
}
if (*buffer)
err = gpgsm_qualified_consent (ctrl, cl->cert);
else
err = gpgsm_not_qualified_warning (ctrl, cl->cert);
if (err)
{
rc = err;
goto leave;
}
}
}
/* Prepare hashing (actually we are figuring out what we have set
above). */
rc = gcry_md_open (&data_md, 0, 0);
if (rc)
{
log_error ("md_open failed: %s\n", gpg_strerror (rc));
goto leave;
}
if (DBG_HASHING)
gcry_md_start_debug (data_md, "sign.data");
for (i=0; (algoid=ksba_cms_get_digest_algo_list (cms, i)); i++)
{
algo = gcry_md_map_name (algoid);
if (!algo)
{
log_error ("unknown hash algorithm `%s'\n", algoid? algoid:"?");
rc = gpg_error (GPG_ERR_BUG);
goto leave;
}
gcry_md_enable (data_md, algo);
audit_log_i (ctrl->audit, AUDIT_DATA_HASH_ALGO, algo);
}
audit_log (ctrl->audit, AUDIT_SETUP_READY);
if (detached)
{ /* We hash the data right now so that we can store the message
digest. ksba_cms_build() takes this as an flag that detached
data is expected. */
unsigned char *digest;
size_t digest_len;
if (!hash_data (data_fd, data_md))
audit_log (ctrl->audit, AUDIT_GOT_DATA);
for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
{
digest = gcry_md_read (data_md, cl->hash_algo);
digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
if ( !digest || !digest_len )
{
log_error ("problem getting the hash of the data\n");
rc = gpg_error (GPG_ERR_BUG);
goto leave;
}
err = ksba_cms_set_message_digest (cms, signer, digest, digest_len);
if (err)
{
log_error ("ksba_cms_set_message_digest failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
}
}
gnupg_get_isotime (signed_at);
for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
{
err = ksba_cms_set_signing_time (cms, signer, signed_at);
if (err)
{
log_error ("ksba_cms_set_signing_time failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
}
/* We need to write at least a minimal list of our capabilities to
try to convince some MUAs to use 3DES and not the crippled
RC2. Our list is:
aes128-CBC
des-EDE3-CBC
*/
err = ksba_cms_add_smime_capability (cms, "2.16.840.1.101.3.4.1.2", NULL, 0);
if (!err)
err = ksba_cms_add_smime_capability (cms, "1.2.840.113549.3.7", NULL, 0);
if (err)
{
log_error ("ksba_cms_add_smime_capability failed: %s\n",
gpg_strerror (err));
goto leave;
}
/* Main building loop. */
do
{
err = ksba_cms_build (cms, &stopreason);
if (err)
{
log_debug ("ksba_cms_build failed: %s\n", gpg_strerror (err));
rc = err;
goto leave;
}
if (stopreason == KSBA_SR_BEGIN_DATA)
{
/* Hash the data and store the message digest. */
unsigned char *digest;
size_t digest_len;
assert (!detached);
rc = hash_and_copy_data (data_fd, data_md, writer);
if (rc)
goto leave;
audit_log (ctrl->audit, AUDIT_GOT_DATA);
for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
{
digest = gcry_md_read (data_md, cl->hash_algo);
digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
if ( !digest || !digest_len )
{
log_error ("problem getting the hash of the data\n");
rc = gpg_error (GPG_ERR_BUG);
goto leave;
}
err = ksba_cms_set_message_digest (cms, signer,
digest, digest_len);
if (err)
{
log_error ("ksba_cms_set_message_digest failed: %s\n",
gpg_strerror (err));
rc = err;
goto leave;
}
}
}
else if (stopreason == KSBA_SR_NEED_SIG)
{
/* Compute the signature for all signers. */
gcry_md_hd_t md;
rc = gcry_md_open (&md, 0, 0);
if (rc)
{
log_error ("md_open failed: %s\n", gpg_strerror (rc));
goto leave;
}
if (DBG_HASHING)
gcry_md_start_debug (md, "sign.attr");
ksba_cms_set_hash_function (cms, HASH_FNC, md);
for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
{
unsigned char *sigval = NULL;
char *buf, *fpr;
audit_log_i (ctrl->audit, AUDIT_NEW_SIG, signer);
if (signer)
gcry_md_reset (md);
{
certlist_t cl_tmp;
for (cl_tmp=signerlist; cl_tmp; cl_tmp = cl_tmp->next)
{
gcry_md_enable (md, cl_tmp->hash_algo);
audit_log_i (ctrl->audit, AUDIT_ATTR_HASH_ALGO,
cl_tmp->hash_algo);
}
}
rc = ksba_cms_hash_signed_attrs (cms, signer);
if (rc)
{
log_debug ("hashing signed attrs failed: %s\n",
gpg_strerror (rc));
gcry_md_close (md);
goto leave;
}
rc = gpgsm_create_cms_signature (ctrl, cl->cert,
md, cl->hash_algo, &sigval);
if (rc)
{
audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, rc);
gcry_md_close (md);
goto leave;
}
err = ksba_cms_set_sig_val (cms, signer, sigval);
xfree (sigval);
if (err)
{
audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, err);
log_error ("failed to store the signature: %s\n",
gpg_strerror (err));
rc = err;
gcry_md_close (md);
goto leave;
}
/* write a status message */
fpr = gpgsm_get_fingerprint_hexstring (cl->cert, GCRY_MD_SHA1);
if (!fpr)
{
rc = gpg_error (GPG_ERR_ENOMEM);
gcry_md_close (md);
goto leave;
}
rc = 0;
{
int pkalgo = gpgsm_get_key_algo_info (cl->cert, NULL);
buf = xtryasprintf ("%c %d %d 00 %s %s",
detached? 'D':'S',
pkalgo,
cl->hash_algo,
signed_at,
fpr);
if (!buf)
rc = gpg_error_from_syserror ();
}
xfree (fpr);
if (rc)
{
gcry_md_close (md);
goto leave;
}
gpgsm_status (ctrl, STATUS_SIG_CREATED, buf);
xfree (buf);
audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, 0);
}
gcry_md_close (md);
}
}
while (stopreason != KSBA_SR_READY);
rc = gpgsm_finish_writer (b64writer);
if (rc)
{
log_error ("write failed: %s\n", gpg_strerror (rc));
goto leave;
}
audit_log (ctrl->audit, AUDIT_SIGNING_DONE);
log_info ("signature created\n");
leave:
if (rc)
log_error ("error creating signature: %s <%s>\n",
gpg_strerror (rc), gpg_strsource (rc) );
if (release_signerlist)
gpgsm_release_certlist (signerlist);
ksba_cms_release (cms);
gpgsm_destroy_writer (b64writer);
keydb_release (kh);
gcry_md_close (data_md);
return rc;
}
View Git Blame Copy Permalink