2 * This file is part of PowerDNS or dnsdist.
3 * Copyright -- PowerDNS.COM B.V. and its contributors
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of version 2 of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * In addition, for the avoidance of any doubt, permission is granted to
10 * link this program with OpenSSL and to (re)distribute the binaries
11 * produced as the result of such linking.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
27 /* let's just define a few types and values so that the rest of
28 the code can ignore whether DNSCrypt support is available */
29 #define DNSCRYPT_MAX_RESPONSE_PADDING_AND_MAC_SIZE (0)
37 DNSCryptQuery(const std::shared_ptr<DNSCryptContext>& ctx): d_ctx(ctx)
41 std::shared_ptr<DNSCryptContext> d_ctx{nullptr};
44 #else /* HAVE_DNSCRYPT */
49 #include <arpa/inet.h>
56 #define DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE (crypto_sign_ed25519_PUBLICKEYBYTES)
57 #define DNSCRYPT_PROVIDER_PRIVATE_KEY_SIZE (crypto_sign_ed25519_SECRETKEYBYTES)
58 #define DNSCRYPT_SIGNATURE_SIZE (crypto_sign_ed25519_BYTES)
60 #define DNSCRYPT_PUBLIC_KEY_SIZE (crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES)
61 #define DNSCRYPT_PRIVATE_KEY_SIZE (crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES)
62 #define DNSCRYPT_NONCE_SIZE (crypto_box_curve25519xsalsa20poly1305_NONCEBYTES)
63 #define DNSCRYPT_BEFORENM_SIZE (crypto_box_curve25519xsalsa20poly1305_BEFORENMBYTES)
64 #define DNSCRYPT_MAC_SIZE (crypto_box_curve25519xsalsa20poly1305_MACBYTES)
66 #ifdef HAVE_CRYPTO_BOX_CURVE25519XCHACHA20POLY1305_EASY
67 static_assert(crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES == crypto_box_curve25519xchacha20poly1305_PUBLICKEYBYTES, "DNSCrypt public key size should be the same for all exchange versions");
68 static_assert(crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES == crypto_box_curve25519xchacha20poly1305_SECRETKEYBYTES, "DNSCrypt private key size should be the same for all exchange versions");
69 static_assert(crypto_box_curve25519xchacha20poly1305_NONCEBYTES == crypto_box_curve25519xsalsa20poly1305_NONCEBYTES, "DNSCrypt nonce size should be the same for all exchange versions");
70 static_assert(crypto_box_curve25519xsalsa20poly1305_MACBYTES == crypto_box_curve25519xchacha20poly1305_MACBYTES, "DNSCrypt MAC size should be the same for all exchange versions");
71 static_assert(crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES == crypto_box_curve25519xsalsa20poly1305_BEFORENMBYTES, "DNSCrypt BEFORENM size should be the same for all exchange versions");
72 #endif /* HAVE_CRYPTO_BOX_CURVE25519XCHACHA20POLY1305_EASY */
74 #define DNSCRYPT_CERT_MAGIC_SIZE (4)
75 #define DNSCRYPT_CERT_MAGIC_VALUE { 0x44, 0x4e, 0x53, 0x43 }
76 #define DNSCRYPT_CERT_PROTOCOL_MINOR_VERSION_VALUE { 0x00, 0x00 }
77 #define DNSCRYPT_CLIENT_MAGIC_SIZE (8)
78 #define DNSCRYPT_RESOLVER_MAGIC { 0x72, 0x36, 0x66, 0x6e, 0x76, 0x57, 0x6a, 0x38 }
79 #define DNSCRYPT_RESOLVER_MAGIC_SIZE (8)
80 #define DNSCRYPT_PADDED_BLOCK_SIZE (64)
81 #define DNSCRYPT_MAX_TCP_PADDING_SIZE (256)
82 #define DNSCRYPT_MAX_RESPONSE_PADDING_SIZE (256)
83 #define DNSCRYPT_MAX_RESPONSE_PADDING_AND_MAC_SIZE (DNSCRYPT_MAX_RESPONSE_PADDING_SIZE + DNSCRYPT_MAC_SIZE)
85 /* "The client must check for new certificates every hour", so let's use one hour TTL */
86 #define DNSCRYPT_CERTIFICATE_RESPONSE_TTL (3600)
88 static_assert(DNSCRYPT_CLIENT_MAGIC_SIZE <= DNSCRYPT_PUBLIC_KEY_SIZE, "DNSCrypt Client Nonce size should be smaller or equal to public key size.");
90 #define DNSCRYPT_CERT_ES_VERSION1_VALUE { 0x00, 0x01 }
91 #define DNSCRYPT_CERT_ES_VERSION2_VALUE { 0x00, 0x02 }
93 class DNSCryptContext;
95 struct DNSCryptCertSignedData
97 unsigned char resolverPK[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE];
98 unsigned char clientMagic[DNSCRYPT_CLIENT_MAGIC_SIZE];
107 uint32_t getSerial() const
109 return ntohl(signedData.serial);
111 uint32_t getTSStart() const
113 return signedData.tsStart;
115 uint32_t getTSEnd() const
117 return signedData.tsEnd;
119 bool isValid(time_t now) const
121 return ntohl(getTSStart()) <= static_cast<uint32_t>(now) && static_cast<uint32_t>(now) <= ntohl(getTSEnd());
123 unsigned char magic[DNSCRYPT_CERT_MAGIC_SIZE];
124 unsigned char esVersion[2];
125 unsigned char protocolMinorVersion[2];
126 unsigned char signature[DNSCRYPT_SIGNATURE_SIZE];
127 struct DNSCryptCertSignedData signedData;
130 static_assert((sizeof(DNSCryptCertSignedData) + DNSCRYPT_SIGNATURE_SIZE) == 116, "Dnscrypt cert signed data size + signature size should be 116!");
131 static_assert(sizeof(DNSCryptCert) == 124, "Dnscrypt cert size should be 124!");
133 struct DNSCryptQueryHeader
135 unsigned char clientMagic[DNSCRYPT_CLIENT_MAGIC_SIZE];
136 unsigned char clientPK[DNSCRYPT_PUBLIC_KEY_SIZE];
137 unsigned char clientNonce[DNSCRYPT_NONCE_SIZE / 2];
140 static_assert(sizeof(DNSCryptQueryHeader) == 52, "Dnscrypt query header size should be 52!");
142 struct DNSCryptResponseHeader
144 const unsigned char resolverMagic[DNSCRYPT_RESOLVER_MAGIC_SIZE] = DNSCRYPT_RESOLVER_MAGIC;
145 unsigned char nonce[DNSCRYPT_NONCE_SIZE];
151 } DNSCryptExchangeVersion;
153 class DNSCryptPrivateKey
156 DNSCryptPrivateKey();
157 ~DNSCryptPrivateKey();
158 void loadFromFile(const std::string& keyFile);
159 void saveToFile(const std::string& keyFile) const;
161 unsigned char key[DNSCRYPT_PRIVATE_KEY_SIZE];
164 struct DNSCryptCertificatePair
166 unsigned char publicKey[DNSCRYPT_PUBLIC_KEY_SIZE];
168 DNSCryptPrivateKey privateKey;
175 DNSCryptQuery(const std::shared_ptr<DNSCryptContext>& ctx): d_ctx(ctx)
185 const DNSName& getQName() const
190 uint16_t getID() const
195 const unsigned char* getClientMagic() const
197 return d_header.clientMagic;
200 bool isEncrypted() const
205 void setCertificatePair(const std::shared_ptr<DNSCryptCertificatePair>& pair)
210 void parsePacket(char* packet, uint16_t packetSize, bool tcp, uint16_t* decryptedQueryLen, time_t now);
211 void getDecrypted(bool tcp, char* packet, uint16_t packetSize, uint16_t* decryptedQueryLen);
212 void getCertificateResponse(time_t now, std::vector<uint8_t>& response) const;
213 int encryptResponse(char* response, uint16_t responseLen, uint16_t responseSize, bool tcp, uint16_t* encryptedResponseLen);
215 static const size_t s_minUDPLength = 256;
218 DNSCryptExchangeVersion getVersion() const;
219 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
220 int computeSharedKey();
221 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
222 void fillServerNonce(unsigned char* dest) const;
223 uint16_t computePaddingSize(uint16_t unpaddedLen, size_t maxLen) const;
224 bool parsePlaintextQuery(const char * packet, uint16_t packetSize);
225 bool isEncryptedQuery(const char * packet, uint16_t packetSize, bool tcp, time_t now);
227 DNSCryptQueryHeader d_header;
228 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
229 unsigned char d_sharedKey[crypto_box_BEFORENMBYTES];
230 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
232 std::shared_ptr<DNSCryptContext> d_ctx{nullptr};
233 std::shared_ptr<DNSCryptCertificatePair> d_pair{nullptr};
236 uint16_t d_paddedLen{0};
237 bool d_encrypted{false};
240 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
241 bool d_sharedKeyComputed{false};
242 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
245 class DNSCryptContext
248 static void generateProviderKeys(unsigned char publicKey[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE], unsigned char privateKey[DNSCRYPT_PROVIDER_PRIVATE_KEY_SIZE]);
249 static std::string getProviderFingerprint(unsigned char publicKey[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE]);
250 static void generateCertificate(uint32_t serial, time_t begin, time_t end, const DNSCryptExchangeVersion& version, const unsigned char providerPrivateKey[DNSCRYPT_PROVIDER_PRIVATE_KEY_SIZE], DNSCryptPrivateKey& privateKey, DNSCryptCert& cert);
251 static void saveCertFromFile(const DNSCryptCert& cert, const std::string&filename);
252 static std::string certificateDateToStr(uint32_t date);
253 static void generateResolverKeyPair(DNSCryptPrivateKey& privK, unsigned char pubK[DNSCRYPT_PUBLIC_KEY_SIZE]);
254 static void setExchangeVersion(const DNSCryptExchangeVersion& version, unsigned char esVersion[sizeof(DNSCryptCert::esVersion)]);
255 static DNSCryptExchangeVersion getExchangeVersion(const unsigned char esVersion[sizeof(DNSCryptCert::esVersion)]);
256 static DNSCryptExchangeVersion getExchangeVersion(const DNSCryptCert& cert);
264 DNSCryptContext(const std::string& pName, const std::vector<CertKeyPaths>& certKeys);
265 DNSCryptContext(const std::string& pName, const DNSCryptCert& certificate, const DNSCryptPrivateKey& pKey);
268 void reloadCertificates();
269 void loadNewCertificate(const std::string& certFile, const std::string& keyFile, bool active=true, bool reload=false);
270 void addNewCertificate(const DNSCryptCert& newCert, const DNSCryptPrivateKey& newKey, bool active=true, bool reload=false);
272 void markActive(uint32_t serial);
273 void markInactive(uint32_t serial);
274 void removeInactiveCertificate(uint32_t serial);
275 std::vector<std::shared_ptr<DNSCryptCertificatePair>> getCertificates() { return d_certs; };
276 const DNSName& getProviderName() const { return providerName; }
278 int encryptQuery(char* query, uint16_t queryLen, uint16_t querySize, const unsigned char clientPublicKey[DNSCRYPT_PUBLIC_KEY_SIZE], const DNSCryptPrivateKey& clientPrivateKey, const unsigned char clientNonce[DNSCRYPT_NONCE_SIZE / 2], bool tcp, uint16_t* encryptedResponseLen, const std::shared_ptr<DNSCryptCert>& cert) const;
279 bool magicMatchesAPublicKey(DNSCryptQuery& query, time_t now);
280 void getCertificateResponse(time_t now, const DNSName& qname, uint16_t qid, std::vector<uint8_t>& response);
283 static void computePublicKeyFromPrivate(const DNSCryptPrivateKey& privK, unsigned char pubK[DNSCRYPT_PUBLIC_KEY_SIZE]);
284 static void loadCertFromFile(const std::string&filename, DNSCryptCert& dest);
285 static std::shared_ptr<DNSCryptCertificatePair> loadCertificatePair(const std::string& certFile, const std::string& keyFile);
287 void addNewCertificate(std::shared_ptr<DNSCryptCertificatePair>& newCert, bool reload=false);
289 ReadWriteLock d_lock;
290 std::vector<std::shared_ptr<DNSCryptCertificatePair>> d_certs;
291 std::vector<CertKeyPaths> d_certKeyPaths;
292 DNSName providerName;
295 bool generateDNSCryptCertificate(const std::string& providerPrivateKeyFile, uint32_t serial, time_t begin, time_t end, DNSCryptExchangeVersion version, DNSCryptCert& certOut, DNSCryptPrivateKey& keyOut);