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gpgsm: Add new validation model "steed". 

* sm/gpgsm.h (VALIDATE_FLAG_STEED): New.
* sm/gpgsm.c (gpgsm_parse_validation_model): Add model "steed".
* sm/server.c (option_handler): Allow validation model "steed".
* sm/certlist.c (gpgsm_cert_has_well_known_private_key): New.
* sm/certchain.c (do_validate_chain): Handle the
well-known-private-key attribute.  Support the "steed" model.
(gpgsm_validate_chain): Ditto.
* sm/verify.c (gpgsm_verify): Return "steed" in the trust status line.
* sm/keylist.c (list_cert_colon): Print the new 'w' flag.
--

This is the first part of changes to implement the STEED proposal as
described at http://g10code.com/steed.html .  The idea for X.509 is
not to use plain self-signed certificates but certificates signed by a
dummy CA (i.e. one for which the private key is known).  Having a
single CA as an indication for the use of STEED might help other X.509
implementations to implement STEED.
This commit is contained in:
Werner Koch 2011-12-07 16:15:15 +01:00
parent 14e4fdc9f9
commit 8a12a2000d
9 changed files with 104 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
doc/DETAILS
View File

@ -58,6 +58,10 @@ record; gpg2 does this by default and the option is a dummy.
u = The key is ultimately valid. This often means
that the secret key is available, but any key may
be marked as ultimately valid.
w = The key has a well known private part.
s = The key has special validity. This means that it
might be self-signed and expected to be used in
the STEED sytem.
If the validity information is given for a UID or UAT
record, it describes the validity calculated based on this
@ -347,6 +351,7 @@ more arguments in future versions.
"pgp" for the standard PGP WoT.
"shell" for the standard X.509 model.
"chain" for the chain model.
"steed" for the STEED model.
Note that we use the term "TRUST_" in the status names for
historic reasons; we now speak of validity.

9
doc/gpgsm.texi
View File

@ -451,10 +451,11 @@ address and the time when you verified the signature.
@item --validation-model @var{name}
@opindex validation-model
This option changes the default validation model. The only possible
values are "shell" (which is the default) and "chain" which forces the
use of the chain model. The chain model is also used if an option in
the @file{trustlist.txt} or an attribute of the certificate requests it.
However the standard model (shell) is in that case always tried first.
values are "shell" (which is the default), "chain" which forces the
use of the chain model and "steed" for a new simplified model. The
chain model is also used if an option in the @file{trustlist.txt} or
an attribute of the certificate requests it. However the standard
model (shell) is in that case always tried first.
@item --ignore-cert-extension @var{oid}
@opindex ignore-cert-extension

61
sm/certchain.c
View File

@ -1,6 +1,6 @@
/* certchain.c - certificate chain validation
* Copyright (C) 2001, 2002, 2003, 2004, 2005,
* 2006, 2007, 2008 Free Software Foundation, Inc.
* 2006, 2007, 2008, 2011 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
@ -1193,6 +1193,7 @@ ask_marktrusted (ctrl_t ctrl, ksba_cert_t cert, int listmode)
VALIDATE_FLAG_NO_DIRMNGR - Do not do any dirmngr isvalid checks.
VALIDATE_FLAG_CHAIN_MODEL - Check according to chain model.
VALIDATE_FLAG_STEED - Check according to the STEED model.
*/
static int
do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
@ -1305,13 +1306,21 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
We used to do this only later but changed it to call the
check right here so that we can access special flags
associated with that specific root certificate. */
istrusted_rc = gpgsm_agent_istrusted (ctrl, subject_cert, NULL,
rootca_flags);
if (gpgsm_cert_has_well_known_private_key (subject_cert))
{
memset (rootca_flags, 0, sizeof *rootca_flags);
istrusted_rc = ((flags & VALIDATE_FLAG_STEED)
? 0 : gpg_error (GPG_ERR_NOT_TRUSTED));
}
else
istrusted_rc = gpgsm_agent_istrusted (ctrl, subject_cert, NULL,
rootca_flags);
audit_log_cert (ctrl->audit, AUDIT_ROOT_TRUSTED,
subject_cert, istrusted_rc);
/* If the chain model extended attribute is used, make sure
that our chain model flag is set. */
if (has_validation_model_chain (subject_cert, listmode, listfp))
if (!(flags & VALIDATE_FLAG_STEED)
&& has_validation_model_chain (subject_cert, listmode, listfp))
rootca_flags->chain_model = 1;
}
@ -1383,7 +1392,7 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
/* Set the flag for qualified signatures. This flag is
deduced from a list of root certificates allowed for
qualified signatures. */
if (is_qualified == -1)
if (is_qualified == -1 && !(flags & VALIDATE_FLAG_STEED))
{
gpg_error_t err;
size_t buflen;
@ -1437,8 +1446,11 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
expired it does not make much sense to ask the user
whether we wants to trust the root certificate. We
should do this only if the certificate under question
will then be usable. */
will then be usable. If the certificate has a well
known private key asking the user does not make any
sense. */
if ( !any_expired
&& !gpgsm_cert_has_well_known_private_key (subject_cert)
&& (!listmode || !already_asked_marktrusted (subject_cert))
&& ask_marktrusted (ctrl, subject_cert, listmode) )
rc = 0;
@ -1455,6 +1467,8 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
/* Check for revocations etc. */
if ((flags & VALIDATE_FLAG_NO_DIRMNGR))
;
else if ((flags & VALIDATE_FLAG_STEED))
; /* Fixme: check revocations via DNS. */
else if (opt.no_trusted_cert_crl_check || rootca_flags->relax)
;
else
@ -1586,8 +1600,16 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
performance reasons. */
if (is_root)
{
istrusted_rc = gpgsm_agent_istrusted (ctrl, issuer_cert, NULL,
rootca_flags);
if (gpgsm_cert_has_well_known_private_key (issuer_cert))
{
memset (rootca_flags, 0, sizeof *rootca_flags);
istrusted_rc = ((flags & VALIDATE_FLAG_STEED)
? 0 : gpg_error (GPG_ERR_NOT_TRUSTED));
}
else
istrusted_rc = gpgsm_agent_istrusted
(ctrl, issuer_cert, NULL, rootca_flags);
if (!istrusted_rc && rootca_flags->relax)
{
/* Ignore the error due to the relax flag. */
@ -1627,6 +1649,8 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
be fixed. */
if ((flags & VALIDATE_FLAG_NO_DIRMNGR))
rc = 0;
else if ((flags & VALIDATE_FLAG_STEED))
rc = 0; /* Fixme: XXX */
else if (is_root && (opt.no_trusted_cert_crl_check
|| (!istrusted_rc && rootca_flags->relax)))
rc = 0;
@ -1722,7 +1746,7 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
capability of the certificate under question, store the result as
user data in all certificates of the chain. We do this even if the
validation itself failed. */
if (is_qualified != -1)
if (is_qualified != -1 && !(flags & VALIDATE_FLAG_STEED))
{
gpg_error_t err;
chain_item_t ci;
@ -1780,8 +1804,8 @@ do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg,
do_validate_chain. This function is a wrapper to handle a root
certificate with the chain_model flag set. If RETFLAGS is not
NULL, flags indicating now the verification was done are stored
there. The only defined flag for RETFLAGS is
VALIDATE_FLAG_CHAIN_MODEL.
there. The only defined vits for RETFLAGS are
VALIDATE_FLAG_CHAIN_MODEL and VALIDATE_FLAG_STEED.
If you are verifying a signature you should set CHECKTIME to the
creation time of the signature. If your are verifying a
@ -1801,16 +1825,27 @@ gpgsm_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime,
if (!retflags)
retflags = &dummy_retflags;
/* If the session requested a certain validation mode make sure the
corresponding flags are set. */
if (ctrl->validation_model == 1)
flags |= VALIDATE_FLAG_CHAIN_MODEL;
else if (ctrl->validation_model == 2)
flags |= VALIDATE_FLAG_STEED;
/* If the chain model was forced, set this immediately into
RETFLAGS. */
*retflags = (flags & VALIDATE_FLAG_CHAIN_MODEL);
memset (&rootca_flags, 0, sizeof rootca_flags);
rc = do_validate_chain (ctrl, cert, checktime,
r_exptime, listmode, listfp, flags,
&rootca_flags);
if (gpg_err_code (rc) == GPG_ERR_CERT_EXPIRED
if (!rc && (flags & VALIDATE_FLAG_STEED))
{
*retflags |= VALIDATE_FLAG_STEED;
}
else if (gpg_err_code (rc) == GPG_ERR_CERT_EXPIRED
&& !(flags & VALIDATE_FLAG_CHAIN_MODEL)
&& (rootca_flags.valid && rootca_flags.chain_model))
{
@ -1824,6 +1859,8 @@ gpgsm_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime,
if (opt.verbose)
do_list (0, listmode, listfp, _("validation model used: %s"),
(*retflags & VALIDATE_FLAG_STEED)?
"steed" :
(*retflags & VALIDATE_FLAG_CHAIN_MODEL)?
_("chain"):_("shell"));

17
sm/certlist.c
View File

@ -1,6 +1,6 @@
/* certlist.c - build list of certificates
* Copyright (C) 2001, 2003, 2004, 2005, 2007,
* 2008 Free Software Foundation, Inc.
* 2008, 2011 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
@ -210,6 +210,21 @@ gpgsm_cert_use_ocsp_p (ksba_cert_t cert)
}
/* Return true if CERT has the well known private key extension. */
int
gpgsm_cert_has_well_known_private_key (ksba_cert_t cert)
{
int idx;
const char *oid;
for (idx=0; !ksba_cert_get_extension (cert, idx,
&oid, NULL, NULL, NULL);idx++)
if (!strcmp (oid, "1.3.6.1.4.1.11591.2.2.2") )
return 1; /* Yes. */
return 0; /* No. */
}
static int
same_subject_issuer (const char *subject, const char *issuer, ksba_cert_t cert)
{

2
sm/gpgsm.c
View File

@ -2004,6 +2004,8 @@ gpgsm_parse_validation_model (const char *model)
return 0;
else if ( !ascii_strcasecmp (model, "chain") )
return 1;
else if ( !ascii_strcasecmp (model, "steed") )
return 2;
else
return -1;
}

7
sm/gpgsm.h
View File

@ -195,7 +195,9 @@ struct server_control_s
certificates up the chain (0 = none, 1 = only
signer) */
int use_ocsp; /* Set to true if OCSP should be used. */
int validation_model; /* Set to 1 for the chain model. */
int validation_model; /* 0 := standard model (shell),
1 := chain model,
2 := STEED model. */
};
@ -307,7 +309,7 @@ int gpgsm_create_cms_signature (ctrl_t ctrl,
/* Flags used with gpgsm_validate_chain. */
#define VALIDATE_FLAG_NO_DIRMNGR 1
#define VALIDATE_FLAG_CHAIN_MODEL 2
#define VALIDATE_FLAG_STEED 4
int gpgsm_walk_cert_chain (ctrl_t ctrl,
ksba_cert_t start, ksba_cert_t *r_next);
@ -326,6 +328,7 @@ int gpgsm_cert_use_verify_p (ksba_cert_t cert);
int gpgsm_cert_use_decrypt_p (ksba_cert_t cert);
int gpgsm_cert_use_cert_p (ksba_cert_t cert);
int gpgsm_cert_use_ocsp_p (ksba_cert_t cert);
int gpgsm_cert_has_well_known_private_key (ksba_cert_t cert);
int gpgsm_certs_identical_p (ksba_cert_t cert_a, ksba_cert_t cert_b);
int gpgsm_add_cert_to_certlist (ctrl_t ctrl, ksba_cert_t cert,
certlist_t *listaddr, int is_encrypt_to);

28
sm/keylist.c
View File

@ -1,6 +1,6 @@
/* keylist.c - Print certificates in various formats.
* Copyright (C) 1998, 1999, 2000, 2001, 2003,
* 2004, 2005, 2008, 2009 Free Software Foundation, Inc.
* Copyright (C) 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2008, 2009,
* 2010, 2011 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
@ -421,7 +421,12 @@ list_cert_colon (ctrl_t ctrl, ksba_cert_t cert, unsigned int validity,
&& *not_after && strcmp (current_time, not_after) > 0 )
*truststring = 'e';
else if (valerr)
*truststring = 'i';
{
if (gpgsm_cert_has_well_known_private_key (cert))
*truststring = 'w'; /* Well, this is dummy CA. */
else
*truststring = 'i';
}
else if (ctrl->with_validation && !is_root)
*truststring = 'f';
}
@ -433,12 +438,17 @@ list_cert_colon (ctrl_t ctrl, ksba_cert_t cert, unsigned int validity,
{
struct rootca_flags_s dummy_flags;
rc = gpgsm_agent_istrusted (ctrl, cert, NULL, &dummy_flags);
if (!rc)
*truststring = 'u'; /* Yes, we trust this one (ultimately). */
else if (gpg_err_code (rc) == GPG_ERR_NOT_TRUSTED)
*truststring = 'n'; /* No, we do not trust this one. */
/* (in case of an error we can't tell anything.) */
if (gpgsm_cert_has_well_known_private_key (cert))
*truststring = 'w'; /* Well, this is dummy CA. */
else
{
rc = gpgsm_agent_istrusted (ctrl, cert, NULL, &dummy_flags);
if (!rc)
*truststring = 'u'; /* Yes, we trust this one (ultimately). */
else if (gpg_err_code (rc) == GPG_ERR_NOT_TRUSTED)
*truststring = 'n'; /* No, we do not trust this one. */
/* (in case of an error we can't tell anything.) */
}
}
if (*truststring)

2
sm/server.c
View File

@ -277,7 +277,7 @@ option_handler (assuan_context_t ctx, const char *key, const char *value)
else if (!strcmp (key, "validation-model"))
{
int i = gpgsm_parse_validation_model (value);
if ( i >= 0 && i <= 1 )
if ( i >= 0 && i <= 2 )
ctrl->validation_model = i;
else
err = gpg_error (GPG_ERR_ASS_PARAMETER);

2
sm/verify.c
View File

@ -624,6 +624,8 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, estream_t out_fp)
}
gpgsm_status (ctrl, STATUS_TRUST_FULLY,
(verifyflags & VALIDATE_FLAG_STEED)?
"0 steed":
(verifyflags & VALIDATE_FLAG_CHAIN_MODEL)?
"0 chain": "0 shell");