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authorLennart Poettering <lennart@poettering.net>2016-01-18 22:33:23 +0100
committerLennart Poettering <lennart@poettering.net>2016-01-18 23:31:16 +0100
commit542e0c84d1518a1515e03194dd25299b2652778c (patch)
tree0c862d869f25f16a2239cbc612165409abc47a3d
parent59a899908f9f1ead3cdb8b87ff98225054b5dab0 (diff)
resolved: never consider following a CNAME/DNAME chain for a CNAME/DNAME lookup
Let's avoid thinking that a CNAME/DNAME chain traversal could be a good idea if QTYPE is already CNAME/DNAME. (Also, let's bail out early when trying to see if some RR is a suitable CNAME/DNAME for some other RR).
-rw-r--r--src/resolve/resolved-dns-query.c2
-rw-r--r--src/resolve/resolved-dns-question.c9
-rw-r--r--src/resolve/resolved-dns-question.h2
3 files changed, 10 insertions, 3 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index 2938238f27..1b7083d7dc 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -1268,7 +1268,7 @@ int dns_query_process_cname(DnsQuery *q) {
if (r > 0)
return DNS_QUERY_MATCH; /* The answer matches directly, no need to follow cnames */
- r = dns_question_matches_cname(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain));
+ r = dns_question_matches_cname_or_dname(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain));
if (r < 0)
return r;
if (r > 0 && !cname)
diff --git a/src/resolve/resolved-dns-question.c b/src/resolve/resolved-dns-question.c
index fb5637779c..1e41a9aa3c 100644
--- a/src/resolve/resolved-dns-question.c
+++ b/src/resolve/resolved-dns-question.c
@@ -108,7 +108,7 @@ int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr, const char *s
return 0;
}
-int dns_question_matches_cname(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
+int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain) {
unsigned i;
int r;
@@ -117,7 +117,14 @@ int dns_question_matches_cname(DnsQuestion *q, DnsResourceRecord *rr, const char
if (!q)
return 0;
+ if (!IN_SET(rr->key->type, DNS_TYPE_CNAME, DNS_TYPE_DNAME))
+ return 0;
+
for (i = 0; i < q->n_keys; i++) {
+ /* For a {C,D}NAME record we can never find a matching {C,D}NAME record */
+ if (!dns_type_may_redirect(q->keys[i]->type))
+ return 0;
+
r = dns_resource_key_match_cname_or_dname(q->keys[i], rr->key, search_domain);
if (r != 0)
return r;
diff --git a/src/resolve/resolved-dns-question.h b/src/resolve/resolved-dns-question.h
index 7ca9224e6f..98e1f0e366 100644
--- a/src/resolve/resolved-dns-question.h
+++ b/src/resolve/resolved-dns-question.h
@@ -45,7 +45,7 @@ int dns_question_new_service(DnsQuestion **ret, const char *service, const char
int dns_question_add(DnsQuestion *q, DnsResourceKey *key);
int dns_question_matches_rr(DnsQuestion *q, DnsResourceRecord *rr, const char *search_domain);
-int dns_question_matches_cname(DnsQuestion *q, DnsResourceRecord *rr, const char* search_domain);
+int dns_question_matches_cname_or_dname(DnsQuestion *q, DnsResourceRecord *rr, const char* search_domain);
int dns_question_is_valid_for_query(DnsQuestion *q);
int dns_question_contains(DnsQuestion *a, const DnsResourceKey *k);
int dns_question_is_equal(DnsQuestion *a, DnsQuestion *b);