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>
55 #define DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE (crypto_sign_ed25519_PUBLICKEYBYTES)
56 #define DNSCRYPT_PROVIDER_PRIVATE_KEY_SIZE (crypto_sign_ed25519_SECRETKEYBYTES)
57 #define DNSCRYPT_SIGNATURE_SIZE (crypto_sign_ed25519_BYTES)
59 #define DNSCRYPT_PUBLIC_KEY_SIZE (crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES)
60 #define DNSCRYPT_PRIVATE_KEY_SIZE (crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES)
61 #define DNSCRYPT_NONCE_SIZE (crypto_box_curve25519xsalsa20poly1305_NONCEBYTES)
62 #define DNSCRYPT_BEFORENM_SIZE (crypto_box_curve25519xsalsa20poly1305_BEFORENMBYTES)
63 #define DNSCRYPT_MAC_SIZE (crypto_box_curve25519xsalsa20poly1305_MACBYTES)
65 #ifdef HAVE_CRYPTO_BOX_CURVE25519XCHACHA20POLY1305_EASY
66 static_assert(crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES == crypto_box_curve25519xchacha20poly1305_PUBLICKEYBYTES, "DNSCrypt public key size should be the same for all exchange versions");
67 static_assert(crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES == crypto_box_curve25519xchacha20poly1305_SECRETKEYBYTES, "DNSCrypt private key size should be the same for all exchange versions");
68 static_assert(crypto_box_curve25519xchacha20poly1305_NONCEBYTES == crypto_box_curve25519xsalsa20poly1305_NONCEBYTES, "DNSCrypt nonce size should be the same for all exchange versions");
69 static_assert(crypto_box_curve25519xsalsa20poly1305_MACBYTES == crypto_box_curve25519xchacha20poly1305_MACBYTES, "DNSCrypt MAC size should be the same for all exchange versions");
70 static_assert(crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES == crypto_box_curve25519xsalsa20poly1305_BEFORENMBYTES, "DNSCrypt BEFORENM size should be the same for all exchange versions");
71 #endif /* HAVE_CRYPTO_BOX_CURVE25519XCHACHA20POLY1305_EASY */
73 #define DNSCRYPT_CERT_MAGIC_SIZE (4)
74 #define DNSCRYPT_CERT_MAGIC_VALUE { 0x44, 0x4e, 0x53, 0x43 }
75 #define DNSCRYPT_CERT_PROTOCOL_MINOR_VERSION_VALUE { 0x00, 0x00 }
76 #define DNSCRYPT_CLIENT_MAGIC_SIZE (8)
77 #define DNSCRYPT_RESOLVER_MAGIC { 0x72, 0x36, 0x66, 0x6e, 0x76, 0x57, 0x6a, 0x38 }
78 #define DNSCRYPT_RESOLVER_MAGIC_SIZE (8)
79 #define DNSCRYPT_PADDED_BLOCK_SIZE (64)
80 #define DNSCRYPT_MAX_TCP_PADDING_SIZE (256)
81 #define DNSCRYPT_MAX_RESPONSE_PADDING_SIZE (256)
82 #define DNSCRYPT_MAX_RESPONSE_PADDING_AND_MAC_SIZE (DNSCRYPT_MAX_RESPONSE_PADDING_SIZE + DNSCRYPT_MAC_SIZE)
84 /* "The client must check for new certificates every hour", so let's use one hour TTL */
85 #define DNSCRYPT_CERTIFICATE_RESPONSE_TTL (3600)
87 static_assert(DNSCRYPT_CLIENT_MAGIC_SIZE <= DNSCRYPT_PUBLIC_KEY_SIZE, "DNSCrypt Client Nonce size should be smaller or equal to public key size.");
89 #define DNSCRYPT_CERT_ES_VERSION1_VALUE { 0x00, 0x01 }
90 #define DNSCRYPT_CERT_ES_VERSION2_VALUE { 0x00, 0x02 }
92 class DNSCryptContext;
94 struct DNSCryptCertSignedData
96 unsigned char resolverPK[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE];
97 unsigned char clientMagic[DNSCRYPT_CLIENT_MAGIC_SIZE];
106 uint32_t getSerial() const
108 return ntohl(signedData.serial);
110 uint32_t getTSStart() const
112 return signedData.tsStart;
114 uint32_t getTSEnd() const
116 return signedData.tsEnd;
118 bool isValid(time_t now) const
120 return ntohl(getTSStart()) <= static_cast<uint32_t>(now) && static_cast<uint32_t>(now) <= ntohl(getTSEnd());
122 unsigned char magic[DNSCRYPT_CERT_MAGIC_SIZE];
123 unsigned char esVersion[2];
124 unsigned char protocolMinorVersion[2];
125 unsigned char signature[DNSCRYPT_SIGNATURE_SIZE];
126 struct DNSCryptCertSignedData signedData;
129 static_assert((sizeof(DNSCryptCertSignedData) + DNSCRYPT_SIGNATURE_SIZE) == 116, "Dnscrypt cert signed data size + signature size should be 116!");
130 static_assert(sizeof(DNSCryptCert) == 124, "Dnscrypt cert size should be 124!");
132 struct DNSCryptQueryHeader
134 unsigned char clientMagic[DNSCRYPT_CLIENT_MAGIC_SIZE];
135 unsigned char clientPK[DNSCRYPT_PUBLIC_KEY_SIZE];
136 unsigned char clientNonce[DNSCRYPT_NONCE_SIZE / 2];
139 static_assert(sizeof(DNSCryptQueryHeader) == 52, "Dnscrypt query header size should be 52!");
141 struct DNSCryptResponseHeader
143 const unsigned char resolverMagic[DNSCRYPT_RESOLVER_MAGIC_SIZE] = DNSCRYPT_RESOLVER_MAGIC;
144 unsigned char nonce[DNSCRYPT_NONCE_SIZE];
150 } DNSCryptExchangeVersion;
152 class DNSCryptPrivateKey
155 DNSCryptPrivateKey();
156 ~DNSCryptPrivateKey();
157 void loadFromFile(const std::string& keyFile);
158 void saveToFile(const std::string& keyFile) const;
160 unsigned char key[DNSCRYPT_PRIVATE_KEY_SIZE];
163 struct DNSCryptCertificatePair
165 unsigned char publicKey[DNSCRYPT_PUBLIC_KEY_SIZE];
167 DNSCryptPrivateKey privateKey;
174 DNSCryptQuery(const std::shared_ptr<DNSCryptContext>& ctx): d_ctx(ctx)
184 const DNSName& getQName() const
189 uint16_t getID() const
194 const unsigned char* getClientMagic() const
196 return d_header.clientMagic;
199 bool isEncrypted() const
204 void setCertificatePair(const std::shared_ptr<DNSCryptCertificatePair>& pair)
209 void parsePacket(char* packet, uint16_t packetSize, bool tcp, uint16_t* decryptedQueryLen, time_t now);
210 void getDecrypted(bool tcp, char* packet, uint16_t packetSize, uint16_t* decryptedQueryLen);
211 void getCertificateResponse(time_t now, std::vector<uint8_t>& response) const;
212 int encryptResponse(char* response, uint16_t responseLen, uint16_t responseSize, bool tcp, uint16_t* encryptedResponseLen);
214 static const size_t s_minUDPLength = 256;
217 DNSCryptExchangeVersion getVersion() const;
218 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
219 int computeSharedKey();
220 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
221 void fillServerNonce(unsigned char* dest) const;
222 uint16_t computePaddingSize(uint16_t unpaddedLen, size_t maxLen) const;
223 bool parsePlaintextQuery(const char * packet, uint16_t packetSize);
224 bool isEncryptedQuery(const char * packet, uint16_t packetSize, bool tcp, time_t now);
226 DNSCryptQueryHeader d_header;
227 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
228 unsigned char d_sharedKey[crypto_box_BEFORENMBYTES];
229 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
231 std::shared_ptr<DNSCryptContext> d_ctx{nullptr};
232 std::shared_ptr<DNSCryptCertificatePair> d_pair{nullptr};
235 uint16_t d_paddedLen{0};
236 bool d_encrypted{false};
239 #ifdef HAVE_CRYPTO_BOX_EASY_AFTERNM
240 bool d_sharedKeyComputed{false};
241 #endif /* HAVE_CRYPTO_BOX_EASY_AFTERNM */
244 class DNSCryptContext
247 static void generateProviderKeys(unsigned char publicKey[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE], unsigned char privateKey[DNSCRYPT_PROVIDER_PRIVATE_KEY_SIZE]);
248 static std::string getProviderFingerprint(unsigned char publicKey[DNSCRYPT_PROVIDER_PUBLIC_KEY_SIZE]);
249 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);
250 static void saveCertFromFile(const DNSCryptCert& cert, const std::string&filename);
251 static std::string certificateDateToStr(uint32_t date);
252 static void generateResolverKeyPair(DNSCryptPrivateKey& privK, unsigned char pubK[DNSCRYPT_PUBLIC_KEY_SIZE]);
253 static void setExchangeVersion(const DNSCryptExchangeVersion& version, unsigned char esVersion[sizeof(DNSCryptCert::esVersion)]);
254 static DNSCryptExchangeVersion getExchangeVersion(const unsigned char esVersion[sizeof(DNSCryptCert::esVersion)]);
255 static DNSCryptExchangeVersion getExchangeVersion(const DNSCryptCert& cert);
263 DNSCryptContext(const std::string& pName, const std::vector<CertKeyPaths>& certKeys);
264 DNSCryptContext(const std::string& pName, const DNSCryptCert& certificate, const DNSCryptPrivateKey& pKey);
267 void reloadCertificates();
268 void loadNewCertificate(const std::string& certFile, const std::string& keyFile, bool active=true, bool reload=false);
269 void addNewCertificate(const DNSCryptCert& newCert, const DNSCryptPrivateKey& newKey, bool active=true, bool reload=false);
271 void markActive(uint32_t serial);
272 void markInactive(uint32_t serial);
273 void removeInactiveCertificate(uint32_t serial);
274 std::vector<std::shared_ptr<DNSCryptCertificatePair>> getCertificates() { return d_certs; };
275 const DNSName& getProviderName() const { return providerName; }
277 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;
278 bool magicMatchesAPublicKey(DNSCryptQuery& query, time_t now);
279 void getCertificateResponse(time_t now, const DNSName& qname, uint16_t qid, std::vector<uint8_t>& response);
282 static void computePublicKeyFromPrivate(const DNSCryptPrivateKey& privK, unsigned char pubK[DNSCRYPT_PUBLIC_KEY_SIZE]);
283 static void loadCertFromFile(const std::string&filename, DNSCryptCert& dest);
284 static std::shared_ptr<DNSCryptCertificatePair> loadCertificatePair(const std::string& certFile, const std::string& keyFile);
286 void addNewCertificate(std::shared_ptr<DNSCryptCertificatePair>& newCert, bool reload=false);
288 pthread_rwlock_t d_lock;
289 std::vector<std::shared_ptr<DNSCryptCertificatePair>> d_certs;
290 std::vector<CertKeyPaths> d_certKeyPaths;
291 DNSName providerName;
294 bool generateDNSCryptCertificate(const std::string& providerPrivateKeyFile, uint32_t serial, time_t begin, time_t end, DNSCryptExchangeVersion version, DNSCryptCert& certOut, DNSCryptPrivateKey& keyOut);