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[9.18] fix: dev: Validating ADB fetches could cause a crash in import_rdataset()

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Previously, in some cases, the resolver could return rdatasets of type CNAME or DNAME without the result code being set to `DNS_R_CNAME` or `DNS_R_DNAME`. This could trigger an assertion failure in the ADB. The resolver error has been fixed.

Closes #5201

Backport of MR !10172

Backport of MR !10178

Merge branch 'backport-5201-adb-cname-error-9.18' into 'bind-9.18'

See merge request isc-projects/bind9!10330
This commit is contained in:
Ondřej Surý 2025-03-26 12:09:19 +00:00
commit f24bacb190
1 changed files with 51 additions and 18 deletions
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69
lib/dns/resolver.c
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@ -6146,11 +6146,24 @@ answer_response:
* Negative results must be indicated in event->result.
*/
INSIST(hevent->rdataset != NULL);
if (dns_rdataset_isassociated(hevent->rdataset) &&
NEGATIVE(hevent->rdataset))
{
INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
if (dns_rdataset_isassociated(hevent->rdataset)) {
if (NEGATIVE(hevent->rdataset)) {
INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
} else if (eresult == ISC_R_SUCCESS &&
hevent->rdataset->type != fctx->type)
{
switch (hevent->rdataset->type) {
case dns_rdatatype_cname:
eresult = DNS_R_CNAME;
break;
case dns_rdatatype_dname:
eresult = DNS_R_DNAME;
break;
default:
break;
}
}
}
hevent->result = eresult;
@ -6799,11 +6812,25 @@ cache_name(fetchctx_t *fctx, dns_name_t *name, dns_message_t *message,
* Negative results must be indicated in
* event->result.
*/
if (dns_rdataset_isassociated(event->rdataset) &&
NEGATIVE(event->rdataset))
{
INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
if (dns_rdataset_isassociated(event->rdataset)) {
if (NEGATIVE(event->rdataset)) {
INSIST(eresult ==
DNS_R_NCACHENXDOMAIN ||
eresult == DNS_R_NCACHENXRRSET);
} else if (eresult == ISC_R_SUCCESS &&
event->rdataset->type != fctx->type)
{
switch (event->rdataset->type) {
case dns_rdatatype_cname:
eresult = DNS_R_CNAME;
break;
case dns_rdatatype_dname:
eresult = DNS_R_DNAME;
break;
default:
break;
}
}
}
event->result = eresult;
if (adbp != NULL && *adbp != NULL) {
@ -6908,15 +6935,21 @@ ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
}
} else {
/*
* Either we don't care about the nature of the
* cache rdataset (because no fetch is
* interested in the outcome), or the cache
* rdataset is not a negative cache entry.
* Whichever case it is, we can return success.
*
* XXXRTH There's a CNAME/DNAME problem here.
* The attempt to add a negative cache entry
* was rejected. Set *eresultp to reflect
* the type of the dataset being returned.
*/
*eresultp = ISC_R_SUCCESS;
switch (ardataset->type) {
case dns_rdatatype_cname:
*eresultp = DNS_R_CNAME;
break;
case dns_rdatatype_dname:
*eresultp = DNS_R_DNAME;
break;
default:
*eresultp = ISC_R_SUCCESS;
break;
}
}
result = ISC_R_SUCCESS;
}