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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_BASE_DNSSEC_CHAIN_VERIFIER_H_
#define NET_BASE_DNSSEC_CHAIN_VERIFIER_H_
#include <map>
#include <string>
#include <vector>
#include "base/string_piece.h"
namespace net {
// DNSSECChainVerifier verifies a chain of DNSSEC records. These records
// eventually prove the validity of a set of resource records for the target
// name. For example, if the fingerprint of a certificate was stored in a CERT
// record for a given domain, then a chain could prove the validity of that
// fingerprint.
class DNSSECChainVerifier {
public:
enum Error {
OK = 0,
BAD_DATA, // The chain was corrupt in some fashion.
UNKNOWN_ROOT_KEY, // The chain is assuming an unknown DNS root.
UNKNOWN_DIGEST, // An omitted DS record used an unknown hash function.
UNKNOWN_TERMINAL_RRTYPE, // The chain proved an unknown RRTYPE.
BAD_SIGNATURE, // One of the signature was incorrect.
NO_DS_LINK, // a DS set didn't include the next entry key.
OFF_COURSE, // the chain is diverging from the target name.
BAD_TARGET, // the chain didn't end up at the target.
};
// |target|: the target hostname. This must be in canonical (all
// lower-case), length-prefixed DNS form. For example:
// "\003www\007example\003com\000"
// |chain|: the contents of the chain.
DNSSECChainVerifier(const std::string& target,
const base::StringPiece& chain);
~DNSSECChainVerifier();
// If called, timestamps in the signatures will be ignored. This is for
// testing only.
void IgnoreTimestamps();
// Verify verifies the chain. Returns |OK| on success.
Error Verify();
// rrtype returns the RRTYPE of the proven resource records. Only call this
// after Verify has returned OK.
uint16 rrtype() const;
// rrdatas returns the contents of the proven resource records. Only call
// this after Verify has returned OK.
const std::vector<base::StringPiece>& rrdatas() const;
// ParseTLSTXTRecord parses a TXT record which should contain TLS fingerprint
// information.
// rrdata: the raw TXT RRDATA from DNS
// returns: an empty map on failure, or the result of the parse.
static std::map<std::string, std::string>
ParseTLSTXTRecord(base::StringPiece rrdata);
// Exposed for testing only.
static unsigned MatchingLabels(base::StringPiece a,
base::StringPiece b);
private:
struct Zone;
bool U8(uint8*);
bool U16(uint16*);
bool VariableLength16(base::StringPiece*);
bool ReadName(base::StringPiece*);
bool ReadAheadEntryKey(base::StringPiece*);
bool ReadAheadKey(base::StringPiece*, uint8 entry_key);
bool ReadDNSKEYs(std::vector<base::StringPiece>*, bool is_root);
bool DigestKey(base::StringPiece* digest,
const base::StringPiece& name,
const base::StringPiece& dnskey,
uint8 digest_type,
uint16 keyid,
uint8 algorithm);
Error EnterRoot();
Error EnterZone(const base::StringPiece& zone);
Error LeaveZone(base::StringPiece* next_name);
Error ReadDSSet(std::vector<base::StringPiece>*,
const base::StringPiece& next_name);
Error ReadGenericRRs(std::vector<base::StringPiece>*);
Error ReadCNAME(std::vector<base::StringPiece>*);
Zone* current_zone_;
std::string target_;
base::StringPiece chain_;
bool ignore_timestamps_;
bool valid_;
// already_entered_zone_ is set to true when we unwind a Zone chain and start
// off from a point where we have already entered a zone.
bool already_entered_zone_;
uint16 rrtype_;
std::vector<base::StringPiece> rrdatas_;
// A list of pointers which need to be free()ed on destruction.
std::vector<void*> scratch_pool_;
};
} // namespace net
#endif // NET_BASE_DNSSEC_CHAIN_VERIFIER_H_
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