+30 September 2008: Wouter
+ - fixup SHA256 DS downgrade, no longer possible to downgrade to SHA1.
+ - tests for sha256 support and downgrade resistance.
+
29 September 2008: Wouter
- EDNS lameness detection, if EDNS packets are dropped this is
detected, eventually.
--- /dev/null
+; config options
+; The island of trust is at example.com
+server:
+ trust-anchor: "example.com. 3600 IN DS 2854 3 1 46e4ffc6e9a4793b488954bd3f0cc6af0dfb201b"
+ val-override-date: "20070916134226"
+
+stub-zone:
+ name: "."
+ stub-addr: 193.0.14.129 # K.ROOT-SERVERS.NET.
+CONFIG_END
+
+SCENARIO_BEGIN Test validator with SHA256 DS digest
+
+; K.ROOT-SERVERS.NET.
+RANGE_BEGIN 0 100
+ ADDRESS 193.0.14.129
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+. IN NS
+SECTION ANSWER
+. IN NS K.ROOT-SERVERS.NET.
+SECTION ADDITIONAL
+K.ROOT-SERVERS.NET. IN A 193.0.14.129
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION AUTHORITY
+com. IN NS a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net. IN A 192.5.6.30
+ENTRY_END
+RANGE_END
+
+; a.gtld-servers.net.
+RANGE_BEGIN 0 100
+ ADDRESS 192.5.6.30
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+com. IN NS
+SECTION ANSWER
+com. IN NS a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net. IN A 192.5.6.30
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION AUTHORITY
+example.com. IN NS ns.example.com.
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ENTRY_END
+RANGE_END
+
+; ns.example.com.
+RANGE_BEGIN 0 100
+ ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION ANSWER
+example.com. IN NS ns.example.com.
+example.com. 3600 IN RRSIG NS 3 2 3600 20070926134150 20070829134150 2854 example.com. MC0CFQCN+qHdJxoI/2tNKwsb08pra/G7aAIUAWA5sDdJTbrXA1/3OaesGBAO3sI= ;{id = 2854}
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ns.example.com. 3600 IN RRSIG A 3 3 3600 20070926135752 20070829135752 2854 example.com. MC0CFQCMSWxVehgOQLoYclB9PIAbNP229AIUeH0vNNGJhjnZiqgIOKvs1EhzqAo= ;{id = 2854}
+ENTRY_END
+
+; response to DNSKEY priming query
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN DNSKEY
+SECTION ANSWER
+example.com. 3600 IN DNSKEY 256 3 3 ALXLUsWqUrY3JYER3T4TBJII s70j+sDS/UT2QRp61SE7S3E EXopNXoFE73JLRmvpi/UrOO/Vz4Se 6wXv/CYCKjGw06U4WRgR YXcpEhJROyNapmdIKSx hOzfLVE1gqA0PweZR8d tY3aNQSRn3sPpwJr6Mi /PqQKAMMrZ9ckJpf1+b QMOOvxgzz2U1GS18b3y ZKcgTMEaJzd/GZYzi/B N2DzQ0MsrSwYXfsNLFO Bbs8PJMW4LYIxeeOe6rUgkWOF 7CC9Dh/dduQ1QrsJhmZAEFfd6ByYV+ ;{id = 2854 (zsk), size = 1688b}
+example.com. 3600 IN RRSIG DNSKEY DSA 2 3600 20070926134150 20070829134150 2854 example.com. MCwCFBQRtlR4BEv9ohi+PGFjp+AHsJuHAhRCvz0shggvnvI88DFnBDCczHUcVA== ;{id = 2854}
+SECTION AUTHORITY
+example.com. IN NS ns.example.com.
+example.com. 3600 IN RRSIG NS 3 2 3600 20070926134150 20070829134150 2854 example.com. MC0CFQCN+qHdJxoI/2tNKwsb08pra/G7aAIUAWA5sDdJTbrXA1/3OaesGBAO3sI= ;{id = 2854}
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ns.example.com. 3600 IN RRSIG A 3 3 3600 20070926135752 20070829135752 2854 example.com. MC0CFQCMSWxVehgOQLoYclB9PIAbNP229AIUeH0vNNGJhjnZiqgIOKvs1EhzqAo= ;{id = 2854}
+ENTRY_END
+
+; response for delegation to sub.example.com.
+ENTRY_BEGIN
+MATCH opcode subdomain
+ADJUST copy_id copy_query
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN A
+SECTION ANSWER
+SECTION AUTHORITY
+sub.example.com. IN NS ns.sub.example.com.
+
+; SHA256 DS for sub.example.com.
+sub.example.com. 3600 IN DS 30899 5 2 51be8e847cc663f2775d0f2b6d15e41553c97ecb99b8dd667f18244e2f652033
+sub.example.com. 3600 IN RRSIG DS 3 3 3600 20070926135752 20070829135752 2854 example.com. AJ6FL7yKjrpEEO8WMKlG7TVZoGjgFblJeu0rkJCmJxfdeh6ysUlWQWs= ;{id = 2854}
+
+; SHA1 DS for sub.example.com.
+;sub.example.com. 3600 IN DS 30899 RSASHA1 1 f7ed618f24d5e5202927e1d27bc2e84a141cb4b3
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ENTRY_END
+
+RANGE_END
+
+; ns.sub.example.com.
+RANGE_BEGIN 0 100
+ ADDRESS 1.2.3.6
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN NS
+SECTION ANSWER
+sub.example.com. IN NS ns.sub.example.com.
+sub.example.com. 3600 IN RRSIG NS 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. wcpHeBILHfo8C9uxMhcW03gcURZeUffiKdSTb50ZjzTHgMNhRyMfpcvSpXEd9548A9UTmWKeLZChfr5Z/glONw== ;{id = 30899}
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ns.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. UF7shD/gt1FOp2UHgLTNbPzVykklSXFMEtJ1xD+Hholwf/PIzd7zoaIttIYibNa4fUXCqMg22H9P7MRhfmFe6g== ;{id = 30899}
+ENTRY_END
+
+; response to DNSKEY priming query
+; sub.example.com. 3600 IN DS 30899 RSASHA1 1 f7ed618f24d5e5202927e1d27bc2e84a141cb4b3
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN DNSKEY
+SECTION ANSWER
+sub.example.com. 3600 IN DNSKEY 256 3 5 AQPQ41chR9DEHt/aIzIFAqanbDlRflJoRs5yz1jFsoRIT7dWf0r+PeDuewdxkszNH6wnU4QL8pfKFRh5PIYVBLK3 ;{id = 30899 (zsk), size = 512b}
+sub.example.com. 3600 IN RRSIG DNSKEY 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. uNGp99iznjD7oOX02XnQbDnbg75UwBHRvZSKYUorTKvPUnCWMHKdRsQ+mf+Fx3GZ+Fz9BVjoCmQqpnfgXLEYqw== ;{id = 30899}
+SECTION AUTHORITY
+sub.example.com. IN NS ns.sub.example.com.
+sub.example.com. 3600 IN RRSIG NS 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. wcpHeBILHfo8C9uxMhcW03gcURZeUffiKdSTb50ZjzTHgMNhRyMfpcvSpXEd9548A9UTmWKeLZChfr5Z/glONw== ;{id = 30899}
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ns.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. UF7shD/gt1FOp2UHgLTNbPzVykklSXFMEtJ1xD+Hholwf/PIzd7zoaIttIYibNa4fUXCqMg22H9P7MRhfmFe6g== ;{id = 30899}
+ENTRY_END
+
+; response to query of interest
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION ANSWER
+www.sub.example.com. IN A 11.11.11.11
+www.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. 0DqqRfRtm7VSEQ4mmBbzrKRqQAay3JAE8DPDGmjtokrrjN9F1G/HxozDV7bjdIh2EChlQea8FPwf/GepJMUVxg== ;{id = 30899}
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+RANGE_END
+
+STEP 1 QUERY
+ENTRY_BEGIN
+REPLY RD DO
+SECTION QUESTION
+www.sub.example.com. IN A
+ENTRY_END
+
+; recursion happens here.
+STEP 10 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all
+REPLY QR RD RA AD NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION ANSWER
+www.sub.example.com. 3600 IN A 11.11.11.11
+www.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. 0DqqRfRtm7VSEQ4mmBbzrKRqQAay3JAE8DPDGmjtokrrjN9F1G/HxozDV7bjdIh2EChlQea8FPwf/GepJMUVxg== ;{id = 30899}
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+
+SCENARIO_END
--- /dev/null
+; config options
+; The island of trust is at example.com
+server:
+ trust-anchor: "example.com. 3600 IN DS 2854 3 1 46e4ffc6e9a4793b488954bd3f0cc6af0dfb201b"
+ val-override-date: "20070916134226"
+
+stub-zone:
+ name: "."
+ stub-addr: 193.0.14.129 # K.ROOT-SERVERS.NET.
+CONFIG_END
+
+SCENARIO_BEGIN Test validator with SHA256 DS downgrade to SHA1
+
+; K.ROOT-SERVERS.NET.
+RANGE_BEGIN 0 100
+ ADDRESS 193.0.14.129
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+. IN NS
+SECTION ANSWER
+. IN NS K.ROOT-SERVERS.NET.
+SECTION ADDITIONAL
+K.ROOT-SERVERS.NET. IN A 193.0.14.129
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION AUTHORITY
+com. IN NS a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net. IN A 192.5.6.30
+ENTRY_END
+RANGE_END
+
+; a.gtld-servers.net.
+RANGE_BEGIN 0 100
+ ADDRESS 192.5.6.30
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+com. IN NS
+SECTION ANSWER
+com. IN NS a.gtld-servers.net.
+SECTION ADDITIONAL
+a.gtld-servers.net. IN A 192.5.6.30
+ENTRY_END
+
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION AUTHORITY
+example.com. IN NS ns.example.com.
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ENTRY_END
+RANGE_END
+
+; ns.example.com.
+RANGE_BEGIN 0 100
+ ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN NS
+SECTION ANSWER
+example.com. IN NS ns.example.com.
+example.com. 3600 IN RRSIG NS 3 2 3600 20070926134150 20070829134150 2854 example.com. MC0CFQCN+qHdJxoI/2tNKwsb08pra/G7aAIUAWA5sDdJTbrXA1/3OaesGBAO3sI= ;{id = 2854}
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ns.example.com. 3600 IN RRSIG A 3 3 3600 20070926135752 20070829135752 2854 example.com. MC0CFQCMSWxVehgOQLoYclB9PIAbNP229AIUeH0vNNGJhjnZiqgIOKvs1EhzqAo= ;{id = 2854}
+ENTRY_END
+
+; response to DNSKEY priming query
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+example.com. IN DNSKEY
+SECTION ANSWER
+example.com. 3600 IN DNSKEY 256 3 3 ALXLUsWqUrY3JYER3T4TBJII s70j+sDS/UT2QRp61SE7S3E EXopNXoFE73JLRmvpi/UrOO/Vz4Se 6wXv/CYCKjGw06U4WRgR YXcpEhJROyNapmdIKSx hOzfLVE1gqA0PweZR8d tY3aNQSRn3sPpwJr6Mi /PqQKAMMrZ9ckJpf1+b QMOOvxgzz2U1GS18b3y ZKcgTMEaJzd/GZYzi/B N2DzQ0MsrSwYXfsNLFO Bbs8PJMW4LYIxeeOe6rUgkWOF 7CC9Dh/dduQ1QrsJhmZAEFfd6ByYV+ ;{id = 2854 (zsk), size = 1688b}
+example.com. 3600 IN RRSIG DNSKEY DSA 2 3600 20070926134150 20070829134150 2854 example.com. MCwCFBQRtlR4BEv9ohi+PGFjp+AHsJuHAhRCvz0shggvnvI88DFnBDCczHUcVA== ;{id = 2854}
+SECTION AUTHORITY
+example.com. IN NS ns.example.com.
+example.com. 3600 IN RRSIG NS 3 2 3600 20070926134150 20070829134150 2854 example.com. MC0CFQCN+qHdJxoI/2tNKwsb08pra/G7aAIUAWA5sDdJTbrXA1/3OaesGBAO3sI= ;{id = 2854}
+SECTION ADDITIONAL
+ns.example.com. IN A 1.2.3.4
+ns.example.com. 3600 IN RRSIG A 3 3 3600 20070926135752 20070829135752 2854 example.com. MC0CFQCMSWxVehgOQLoYclB9PIAbNP229AIUeH0vNNGJhjnZiqgIOKvs1EhzqAo= ;{id = 2854}
+ENTRY_END
+
+; response for delegation to sub.example.com.
+ENTRY_BEGIN
+MATCH opcode subdomain
+ADJUST copy_id copy_query
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN A
+SECTION ANSWER
+SECTION AUTHORITY
+sub.example.com. IN NS ns.sub.example.com.
+
+; Downgrade attack: false SHA2, correct SHA1
+
+; SHA256 DS for sub.example.com.
+;sub.example.com. 3600 IN DS 30899 5 2 51be8e847cc663f2775d0f2b6d15e41553c97ecb99b8dd667f18244e2f652033
+; BAD SHA256 DS
+sub.example.com. 3600 IN DS 30899 5 2 51be8e847cc663f2775d0f2b6d15e41553c97ecb99b8dd667f18244e2f652000
+
+; SHA1 DS for sub.example.com.
+sub.example.com. 3600 IN DS 30899 RSASHA1 1 f7ed618f24d5e5202927e1d27bc2e84a141cb4b3
+sub.example.com. 3600 IN RRSIG DS 3 3 3600 20070926135752 20070829135752 2854 example.com. ACqqpk1ow07XJvN1orEpiWOeqMLdDKQtTgWB8Mp6CF/9VTfHuWWmsu8= ;{id = 2854}
+
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ENTRY_END
+
+RANGE_END
+
+; ns.sub.example.com.
+RANGE_BEGIN 0 100
+ ADDRESS 1.2.3.6
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN NS
+SECTION ANSWER
+sub.example.com. IN NS ns.sub.example.com.
+sub.example.com. 3600 IN RRSIG NS 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. wcpHeBILHfo8C9uxMhcW03gcURZeUffiKdSTb50ZjzTHgMNhRyMfpcvSpXEd9548A9UTmWKeLZChfr5Z/glONw== ;{id = 30899}
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ns.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. UF7shD/gt1FOp2UHgLTNbPzVykklSXFMEtJ1xD+Hholwf/PIzd7zoaIttIYibNa4fUXCqMg22H9P7MRhfmFe6g== ;{id = 30899}
+ENTRY_END
+
+; response to DNSKEY priming query
+; sub.example.com. 3600 IN DS 30899 RSASHA1 1 f7ed618f24d5e5202927e1d27bc2e84a141cb4b3
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+sub.example.com. IN DNSKEY
+SECTION ANSWER
+sub.example.com. 3600 IN DNSKEY 256 3 5 AQPQ41chR9DEHt/aIzIFAqanbDlRflJoRs5yz1jFsoRIT7dWf0r+PeDuewdxkszNH6wnU4QL8pfKFRh5PIYVBLK3 ;{id = 30899 (zsk), size = 512b}
+sub.example.com. 3600 IN RRSIG DNSKEY 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. uNGp99iznjD7oOX02XnQbDnbg75UwBHRvZSKYUorTKvPUnCWMHKdRsQ+mf+Fx3GZ+Fz9BVjoCmQqpnfgXLEYqw== ;{id = 30899}
+SECTION AUTHORITY
+sub.example.com. IN NS ns.sub.example.com.
+sub.example.com. 3600 IN RRSIG NS 5 3 3600 20070926134150 20070829134150 30899 sub.example.com. wcpHeBILHfo8C9uxMhcW03gcURZeUffiKdSTb50ZjzTHgMNhRyMfpcvSpXEd9548A9UTmWKeLZChfr5Z/glONw== ;{id = 30899}
+SECTION ADDITIONAL
+ns.sub.example.com. IN A 1.2.3.6
+ns.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. UF7shD/gt1FOp2UHgLTNbPzVykklSXFMEtJ1xD+Hholwf/PIzd7zoaIttIYibNa4fUXCqMg22H9P7MRhfmFe6g== ;{id = 30899}
+ENTRY_END
+
+; response to query of interest
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION ANSWER
+www.sub.example.com. IN A 11.11.11.11
+www.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. 0DqqRfRtm7VSEQ4mmBbzrKRqQAay3JAE8DPDGmjtokrrjN9F1G/HxozDV7bjdIh2EChlQea8FPwf/GepJMUVxg== ;{id = 30899}
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+RANGE_END
+
+STEP 1 QUERY
+ENTRY_BEGIN
+REPLY RD DO
+SECTION QUESTION
+www.sub.example.com. IN A
+ENTRY_END
+
+; recursion happens here.
+; must servfail, BOGUS
+STEP 10 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all
+REPLY QR RD RA SERVFAIL
+SECTION QUESTION
+www.sub.example.com. IN A
+SECTION ANSWER
+;www.sub.example.com. 3600 IN A 11.11.11.11
+;www.sub.example.com. 3600 IN RRSIG A 5 4 3600 20070926134150 20070829134150 30899 sub.example.com. 0DqqRfRtm7VSEQ4mmBbzrKRqQAay3JAE8DPDGmjtokrrjN9F1G/HxozDV7bjdIh2EChlQea8FPwf/GepJMUVxg== ;{id = 30899}
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+
+SCENARIO_END
return (int)rdata[2+2];
}
-/**
- * Get DS RR digest algorithm
- * @param k: DS rrset.
- * @param idx: which DS.
- * @return algorithm or 0 if DS too short.
- */
-static int
+int
ds_get_digest_algo(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
int ds_digest_algo_is_supported(struct ub_packed_rrset_key* ds_rrset,
size_t ds_idx);
+/*
+ * Get DS RR digest algorithm
+ * @param ds_rrset: DS rrset.
+ * @param ds_idx: which DS.
+ * @return algorithm or 0 if DS too short.
+ */
+int ds_get_digest_algo(struct ub_packed_rrset_key* ds_rrset, size_t ds_idx);
+
/**
* See if DS key algorithm is supported
* @param ds_rrset: DS rrset
/* as long as this is false, we can consider this DS rrset to be
* equivalent to no DS rrset. */
int has_useful_ds = 0;
+ int d, digest_algo = 0; /* DS digest algo 0 is not used. */
size_t i, num;
enum sec_status sec;
}
num = rrset_get_count(ds_rrset);
+ /* find favority algo, for now, highest number supported */
for(i=0; i<num; i++) {
- /* Check to see if we can understand this DS. */
if(!ds_digest_algo_is_supported(ds_rrset, i) ||
!ds_key_algo_is_supported(ds_rrset, i)) {
continue;
}
+ d = ds_get_digest_algo(ds_rrset, i);
+ if(d > digest_algo)
+ digest_algo = d;
+ }
+ for(i=0; i<num; i++) {
+ /* Check to see if we can understand this DS.
+ * And check it is the strongest digest */
+ if(!ds_digest_algo_is_supported(ds_rrset, i) ||
+ !ds_key_algo_is_supported(ds_rrset, i) ||
+ ds_get_digest_algo(ds_rrset, i) != digest_algo) {
+ continue;
+ }
/* Once we see a single DS with a known digestID and
* algorithm, we cannot return INSECURE (with a