validator.c revision 93c786e0924aeca2c258e32355349e6ae60a0f72
/*
* Copyright (C) 2000 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#include <config.h>
#include <isc/assertions.h>
#include <isc/buffer.h>
#include <isc/magic.h>
#include <isc/region.h>
#include <isc/result.h>
#include <isc/stdtime.h>
#include <isc/task.h>
#include <isc/util.h>
#include <dns/validator.h>
#include <dns/db.h>
#include <dns/dnssec.h>
#include <dns/events.h>
#include <dns/keytable.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/view.h>
#include <dst/dst.h>
struct dns_validator {
/* Unlocked. */
unsigned int magic;
isc_mutex_t lock;
dns_view_t * view;
/* Locked by lock. */
unsigned int options;
unsigned int attributes;
dns_validatorevent_t * event;
dns_fetch_t * fetch;
dns_validator_t * keyvalidator;
dns_keytable_t * keytable;
dns_keynode_t * keynode;
dst_key_t * key;
};
#define VALIDATOR_MAGIC 0x56616c3fU /* Val?. */
#define VALID_VALIDATOR(v) ISC_MAGIC_VALID(v, VALIDATOR_MAGIC)
#define VALATTR_SHUTDOWN 0x01
#define SHUTDOWN(v) (((v)->attributes & VALATTR_SHUTDOWN) != 0)
/*
* We don't use the SIG RR's _tostruct routine because it copies things.
*/
typedef struct dns_siginfo {
dns_rdatatype_t covers;
dns_secalg_t algorithm;
isc_uint8_t labels;
dns_ttl_t original_ttl;
isc_stdtime_t expiration;
isc_stdtime_t inception;
dns_keytag_t tag;
dns_name_t signer;
isc_region_t signature;
} dns_siginfo_t;
static void
rdata_to_siginfo(dns_rdata_t *rdata, dns_siginfo_t *siginfo) {
isc_buffer_t b;
isc_region_t r;
REQUIRE(rdata->type == 24);
isc_buffer_init(&b, rdata->data, rdata->length, ISC_BUFFERTYPE_BINARY);
isc_buffer_add(&b, rdata->length);
siginfo->covers = (dns_rdatatype_t)isc_buffer_getuint16(&b);
siginfo->algorithm = (dns_secalg_t)isc_buffer_getuint8(&b);
siginfo->labels = isc_buffer_getuint8(&b);
siginfo->original_ttl = (dns_ttl_t)isc_buffer_getuint32(&b);
siginfo->expiration = (isc_stdtime_t)isc_buffer_getuint32(&b);
siginfo->inception = (isc_stdtime_t)isc_buffer_getuint32(&b);
siginfo->tag = (dns_keytag_t)isc_buffer_getuint16(&b);
dns_name_init(&siginfo->signer, NULL);
isc_buffer_remaining(&b, &r);
dns_name_fromregion(&siginfo->signer, &r);
isc_buffer_forward(&b, siginfo->signer.length);
isc_buffer_remaining(&b, &siginfo->signature);
}
static void
validator_done(dns_validator_t *val, isc_result_t result) {
isc_task_t *task;
REQUIRE(val->event != NULL);
/*
* Caller must be holding the lock.
*/
if (result != ISC_R_SUCCESS)
val->event->result = result;
task = val->event->sender;
val->event->sender = val;
isc_task_sendanddetach(&task, (isc_event_t **)&val->event);
}
/*
* Try to find a key that could have signed 'siginfo' among those
* in 'rdataset'. If found, build a dst_key_t for it and point
* val->key at it.
*
* XXX does not handle key tag collisions.
*/
static inline isc_result_t
get_dst_key(dns_validator_t *val, dns_siginfo_t *siginfo,
dns_rdataset_t *rdataset)
{
isc_result_t result;
isc_buffer_t b;
dns_rdata_t rdata;
char ntext[1024];
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
do {
dns_rdataset_current(rdataset, &rdata);
/*
* We keep one byte of ntext in reserve so
* we're sure we can NUL terminate.
*/
isc_buffer_init(&b, ntext, sizeof(ntext) - 1,
ISC_BUFFERTYPE_TEXT);
result = dns_name_totext(&siginfo->signer, ISC_FALSE, &b);
if (result != ISC_R_SUCCESS)
return (result);
/*
* NUL-terminate the character string.
*/
isc_buffer_putuint8(&b, 0);
isc_buffer_init(&b, rdata.data, rdata.length,
ISC_BUFFERTYPE_BINARY);
isc_buffer_add(&b, rdata.length);
INSIST(val->key == NULL);
result = dst_key_fromdns(ntext, &b, val->view->mctx,
&val->key);
if (result != ISC_R_SUCCESS)
return (result);
if (siginfo->algorithm ==
(dns_secalg_t)dst_key_alg(val->key) &&
siginfo->tag ==
(dns_keytag_t)dst_key_id(val->key) &&
dst_key_iszonekey(val->key) &&
dst_key_proto(val->key) == DST_KEYPROTO_DNSSEC) {
/*
* This is the key we're looking for.
*/
return (ISC_R_SUCCESS);
}
dst_key_free(val->key);
val->key = NULL;
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result == ISC_R_NOMORE)
result = ISC_R_NOTFOUND;
return (result);
}
static inline isc_result_t
get_key(dns_validator_t *val, dns_siginfo_t *siginfo) {
isc_result_t result;
dns_validatorevent_t *event;
unsigned int nbits, nlabels;
int order;
dns_namereln_t namereln;
dns_rdataset_t rdataset, sigrdataset;
event = val->event;
/*
* Is the key used for the signature a security root?
*/
INSIST(val->keynode == NULL);
val->keytable = val->view->secroots;
result = dns_keytable_findkeynode(val->view->secroots,
&siginfo->signer,
siginfo->algorithm, siginfo->tag,
&val->keynode);
if (result == ISC_R_NOTFOUND) {
/*
* Is it a trusted key that is not a security root?
*/
val->keytable = val->view->trustedkeys;
result = dns_keytable_findkeynode(val->view->trustedkeys,
&siginfo->signer,
siginfo->algorithm,
siginfo->tag,
&val->keynode);
if (result == ISC_R_SUCCESS) {
/*
* The key is trusted.
*/
val->key = dns_keynode_key(val->keynode);
return (ISC_R_SUCCESS);
} else if (result != ISC_R_NOTFOUND)
return (result);
} else if (result == ISC_R_SUCCESS) {
/*
* The key is a security root.
*/
val->key = dns_keynode_key(val->keynode);
return (ISC_R_SUCCESS);
} else
return (result);
/*
* The signature was not made with a security root or trusted key.
*/
/*
* Is the key name appropriate for this signature?
*/
namereln = dns_name_fullcompare(event->name, &siginfo->signer,
&order, &nlabels, &nbits);
if (event->rdataset->type == dns_rdatatype_key &&
namereln != dns_namereln_subdomain) {
/*
* We don't want a KEY RR to authenticate
* itself, so we ignore the signature if it
* was not made by an ancestor of the KEY.
*/
return (DNS_R_CONTINUE);
} else if (namereln != dns_namereln_subdomain &&
namereln != dns_namereln_equal) {
/*
* The key name is not at the same level
* as 'rdataset', nor is it closer to the
* DNS root.
*/
return (DNS_R_CONTINUE);
}
/*
* Do we know about this key?
*/
dns_rdataset_init(&rdataset);
dns_rdataset_init(&sigrdataset);
result = dns_view_simplefind(val->view, &siginfo->signer,
dns_rdatatype_key, 0,
DNS_DBFIND_PENDINGOK, ISC_FALSE,
&rdataset, &sigrdataset);
if (result == ISC_R_SUCCESS) {
/*
* We have an rrset for the given keyname.
*/
if (rdataset.trust == dns_trust_pending) {
/*
* We know the key but haven't validated it yet.
*/
result = ISC_R_NOTIMPLEMENTED;
} else {
/*
* XXXRTH What should we do if this is an untrusted
* rdataset?
*/
/*
* See if we've got the key used in the signature.
*/
result = get_dst_key(val, siginfo, &rdataset);
if (result != ISC_R_SUCCESS) {
/*
* Either the key we're looking for is not
* in the rrset, or something bad happened.
* Give up.
*/
result = DNS_R_CONTINUE;
}
}
} else if (result == ISC_R_NOTFOUND) {
/*
* We don't know anything about this key.
*
* XXX Start a fetch.
*/
result = ISC_R_NOTIMPLEMENTED;
} else if (result == DNS_R_NCACHENXDOMAIN ||
result == DNS_R_NCACHENXRRSET ||
result == DNS_R_NXDOMAIN ||
result == DNS_R_NXRRSET) {
/*
* This key doesn't exist.
*/
result = DNS_R_CONTINUE;
}
if (dns_rdataset_isassociated(&rdataset))
dns_rdataset_disassociate(&rdataset);
if (dns_rdataset_isassociated(&sigrdataset))
dns_rdataset_disassociate(&sigrdataset);
return (result);
}
static inline isc_result_t
validate(dns_validator_t *val, isc_boolean_t resume) {
isc_result_t result;
dns_validatorevent_t *event;
dns_rdata_t rdata;
dns_siginfo_t siginfo;
/*
* Caller must be holding the validator lock.
*/
event = val->event;
if (resume) {
/* We alraedy have a sigrdataset. */
result = ISC_R_SUCCESS;
} else {
result = dns_rdataset_first(event->sigrdataset);
}
for (;
result == ISC_R_SUCCESS;
result = dns_rdataset_next(event->sigrdataset))
{
dns_rdataset_current(event->sigrdataset, &rdata);
rdata_to_siginfo(&rdata, &siginfo);
/*
* At this point we could check that the signature algorithm
* was known and "sufficiently good". For now, any algorithm
* is acceptable.
*/
if (!resume) {
result = get_key(val, &siginfo);
if (result == DNS_R_CONTINUE)
continue; /* Try the next SIG RR. */
if (result != ISC_R_SUCCESS)
return (result);
}
INSIST(val->key != NULL);
result = dns_dnssec_verify(event->name, event->rdataset,
val->key, val->view->mctx, &rdata);
if (result == ISC_R_SUCCESS)
return (result);
}
return (result);
}
static inline void
validator_start(dns_validator_t *val) {
isc_result_t result;
LOCK(&val->lock);
if (val->event->rdataset != NULL && val->event->sigrdataset != NULL) {
/*
* This looks like a simple validation. We say "looks like"
* because we don't know if wildcards are involved yet so it
* could still get complicated.
*/
result = validate(val, ISC_FALSE);
} else {
/*
* This is a nonexistence validation.
*/
result = ISC_R_NOTIMPLEMENTED;
}
if (result != DNS_R_WAIT)
validator_done(val, result);
UNLOCK(&val->lock);
}
isc_result_t
dns_validator_create(dns_view_t *view, dns_name_t *name,
dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
dns_message_t *message, unsigned int options,
isc_task_t *task, isc_taskaction_t action, void *arg,
dns_validator_t **validatorp)
{
isc_result_t result;
dns_validator_t *val;
isc_task_t *tclone;
dns_validatorevent_t *event;
REQUIRE(validatorp != NULL && *validatorp == NULL);
tclone = NULL;
result = ISC_R_FAILURE;
val = isc_mem_get(view->mctx, sizeof *val);
if (val == NULL)
return (ISC_R_NOMEMORY);
val->view = NULL;
dns_view_attach(view, &val->view);
event = (dns_validatorevent_t *)
isc_event_allocate(view->mctx, task, DNS_EVENT_VALIDATORDONE,
action, arg, sizeof (dns_validatorevent_t));
if (event == NULL) {
result = ISC_R_NOMEMORY;
goto cleanup_val;
}
isc_task_attach(task, &tclone);
event->validator = val;
event->result = ISC_R_FAILURE;
event->name = name;
event->rdataset = rdataset;
event->sigrdataset = sigrdataset;
event->message = message;
result = isc_mutex_init(&val->lock);
if (result != ISC_R_SUCCESS)
goto cleanup_event;
val->event = event;
val->options = options;
val->attributes = 0;
val->fetch = NULL;
val->keyvalidator = NULL;
val->keynode = NULL;
val->magic = VALIDATOR_MAGIC;
validator_start(val);
*validatorp = val;
return (ISC_R_SUCCESS);
cleanup_event:
isc_task_detach(&tclone);
isc_event_free((isc_event_t **)&val->event);
cleanup_val:
dns_view_detach(&val->view);
isc_mem_put(view->mctx, val, sizeof *val);
return (result);
}
void
dns_validator_cancel(dns_validator_t *validator) {
isc_task_t *task;
REQUIRE(VALID_VALIDATOR(validator));
LOCK(&validator->lock);
if (validator->event != NULL) {
validator->event->result = ISC_R_CANCELED;
task = validator->event->sender;
validator->event->sender = validator;
isc_task_sendanddetach(&task,
(isc_event_t **)&validator->event);
/*
* XXXRTH Do other cancelation stuff here.
*/
}
UNLOCK(&validator->lock);
}
static void
destroy(dns_validator_t *val) {
isc_mem_t *mctx;
REQUIRE(SHUTDOWN(val));
REQUIRE(val->event == NULL);
REQUIRE(val->fetch == NULL);
if (val->key != NULL)
dst_key_free(val->key);
if (val->keynode != NULL)
dns_keytable_detachkeynode(val->keytable, &val->keynode);
isc_mutex_destroy(&val->lock);
mctx = val->view->mctx;
dns_view_detach(&val->view);
val->magic = 0;
isc_mem_put(mctx, val, sizeof *val);
}
void
dns_validator_destroy(dns_validator_t **validatorp) {
dns_validator_t *val;
isc_boolean_t want_destroy = ISC_FALSE;
REQUIRE(validatorp != NULL);
val = *validatorp;
REQUIRE(VALID_VALIDATOR(val));
LOCK(&val->lock);
REQUIRE(val->event == NULL);
val->attributes |= VALATTR_SHUTDOWN;
if (val->fetch == NULL)
want_destroy = ISC_TRUE;
UNLOCK(&val->lock);
if (want_destroy)
destroy(val);
*validatorp = NULL;
}