Botan 2.19.1
Crypto and TLS for C&
roughtime.cpp
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1/*
2* Roughtime
3* (C) 2019 Nuno Goncalves <nunojpg@gmail.com>
4*
5* Botan is released under the Simplified BSD License (see license.txt)
6*/
7
8#include <botan/roughtime.h>
9
10#include <botan/base64.h>
11#include <botan/hash.h>
12#include <botan/internal/socket_udp.h>
13#include <botan/pubkey.h>
14#include <botan/rng.h>
15
16#include <cmath>
17#include <map>
18#include <sstream>
19
20namespace Botan {
21
22namespace {
23
24// This exists to work around a LGTM false positive
25static_assert(Roughtime::request_min_size == 1024, "Expected minimum size");
26
27template< bool B, class T = void >
28using enable_if_t = typename std::enable_if<B,T>::type;
29
30template<class T>
31struct is_array : std::false_type {};
32
33template<class T, std::size_t N>
34struct is_array<std::array<T,N>>:std::true_type{};
35
36template<typename T>
37T impl_from_little_endian(const uint8_t* t, const size_t i)
38 {
39 static_assert(sizeof(T) <= sizeof(int64_t), "");
40 return T(static_cast<int64_t>(t[i]) << i * 8) + (i == 0 ? T(0) : impl_from_little_endian<T>(t, i - 1));
41 }
42
43template<typename T>
44T from_little_endian(const uint8_t* t)
45 {
46 return impl_from_little_endian<T>(t, sizeof(T) - 1);
47 }
48
49template<typename T, enable_if_t<is_array<T>::value>* = nullptr>
50T copy(const uint8_t* t)
51 {
52 return typecast_copy<T>(t); //arrays are endianess indepedent, so we do a memcpy
53 }
54
55template<typename T, enable_if_t<!is_array<T>::value>* = nullptr>
56T copy(const uint8_t* t)
57 {
58 return from_little_endian<T>(t); //other types are arithmetic, so we account that roughtime serializes as little endian
59 }
60
61template<typename T>
62std::map<std::string, std::vector<uint8_t>> unpack_roughtime_packet(T bytes)
63 {
64 if(bytes.size() < 8)
65 { throw Roughtime::Roughtime_Error("Map length is under minimum of 8 bytes"); }
66 const auto buf = bytes.data();
67 const uint32_t num_tags = buf[0];
68 const uint32_t start_content = num_tags * 8;
69 if(start_content > bytes.size())
70 { throw Roughtime::Roughtime_Error("Map length too small to contain all tags"); }
71 uint32_t start = start_content;
72 std::map<std::string, std::vector<uint8_t>> tags;
73 for(uint32_t i=0; i<num_tags; ++i)
74 {
75 const size_t end = ((i+1) == num_tags) ? bytes.size() : start_content + from_little_endian<uint32_t>(buf + 4 + i*4);
76 if(end > bytes.size())
77 { throw Roughtime::Roughtime_Error("Tag end index out of bounds"); }
78 if(end < start)
79 { throw Roughtime::Roughtime_Error("Tag offset must be more than previous tag offset"); }
80 const char* label_ptr = cast_uint8_ptr_to_char(buf) + (num_tags+i)*4;
81 const char label[] = {label_ptr[0], label_ptr[1], label_ptr[2], label_ptr[3], 0};
82 auto ret = tags.emplace(label, std::vector<uint8_t>(buf+start, buf+end));
83 if(!ret.second)
84 { throw Roughtime::Roughtime_Error(std::string("Map has duplicated tag: ") + label); }
85 start = static_cast<uint32_t>(end);
86 }
87 return tags;
88 }
89
90template<typename T>
91T get(const std::map<std::string, std::vector<uint8_t>>& map, const std::string& label)
92 {
93 const auto& tag = map.find(label);
94 if(tag == map.end())
95 { throw Roughtime::Roughtime_Error("Tag " + label + " not found"); }
96 if(tag->second.size() != sizeof(T))
97 { throw Roughtime::Roughtime_Error("Tag " + label + " has unexpected size"); }
98 return copy<T>(tag->second.data());
99 }
100
101const std::vector<uint8_t>& get_v(const std::map<std::string, std::vector<uint8_t>>& map, const std::string& label)
102 {
103 const auto& tag = map.find(label);
104 if(tag == map.end())
105 { throw Roughtime::Roughtime_Error("Tag " + label + " not found"); }
106 return tag->second;
107 }
108
109bool verify_signature(const std::array<uint8_t, 32>& pk, const std::vector<uint8_t>& payload,
110 const std::array<uint8_t, 64>& signature)
111 {
112 const char context[] = "RoughTime v1 response signature";
113 Ed25519_PublicKey key(std::vector<uint8_t>(pk.data(), pk.data()+pk.size()));
114 PK_Verifier verifier(key, "Pure");
115 verifier.update(cast_char_ptr_to_uint8(context), sizeof(context)); //add context including \0
116 verifier.update(payload);
117 return verifier.check_signature(signature.data(), signature.size());
118 }
119
120std::array<uint8_t, 64> hashLeaf(const std::array<uint8_t, 64>& leaf)
121 {
122 std::array<uint8_t, 64> ret;
123 std::unique_ptr<HashFunction> hash(HashFunction::create_or_throw("SHA-512"));
124 hash->update(0);
125 hash->update(leaf.data(), leaf.size());
126 hash->final(ret.data());
127 return ret;
128 }
129
130void hashNode(std::array<uint8_t, 64>& hash, const std::array<uint8_t, 64>& node, bool reverse)
131 {
132 std::unique_ptr<HashFunction> h(HashFunction::create_or_throw("SHA-512"));
133 h->update(1);
134 if(reverse)
135 {
136 h->update(node.data(), node.size());
137 h->update(hash.data(), hash.size());
138 }
139 else
140 {
141 h->update(hash.data(), hash.size());
142 h->update(node.data(), node.size());
143 }
144 h->final(hash.data());
145 }
146
147template<size_t N, typename T>
148std::array<uint8_t, N> vector_to_array(std::vector<uint8_t,T> vec)
149 {
150 if(vec.size() != N)
151 { throw std::logic_error("Invalid vector size"); }
152 return typecast_copy<std::array<uint8_t, N>>(vec.data());
153 }
154}
155
156namespace Roughtime {
157
158Nonce::Nonce(const std::vector<uint8_t>& nonce)
159 {
160 if(nonce.size() != 64)
161 { throw Invalid_Argument("Nonce lenght must be 64"); }
162 m_nonce = typecast_copy<std::array<uint8_t, 64>>(nonce.data());
163 }
165 {
166 rng.randomize(m_nonce.data(), m_nonce.size());
167 }
168
169std::array<uint8_t, request_min_size> encode_request(const Nonce& nonce)
170 {
171 std::array<uint8_t, request_min_size> buf = {{2, 0, 0, 0, 64, 0, 0, 0, 'N', 'O', 'N', 'C', 'P', 'A', 'D', 0xff}};
172 std::memcpy(buf.data() + 16, nonce.get_nonce().data(), nonce.get_nonce().size());
173 std::memset(buf.data() + 16 + nonce.get_nonce().size(), 0, buf.size() - 16 - nonce.get_nonce().size());
174 return buf;
175 }
176
177Response Response::from_bits(const std::vector<uint8_t>& response,
178 const Nonce& nonce)
179 {
180 const auto response_v = unpack_roughtime_packet(response);
181 const auto cert = unpack_roughtime_packet(get_v(response_v, "CERT"));
182 const auto cert_dele = get<std::array<uint8_t, 72>>(cert, "DELE");
183 const auto cert_sig = get<std::array<uint8_t, 64>>(cert, "SIG");
184 const auto cert_dele_v = unpack_roughtime_packet(cert_dele);
185 const auto srep = get_v(response_v, "SREP");
186 const auto srep_v = unpack_roughtime_packet(srep);
187
188 const auto cert_dele_pubk = get<std::array<uint8_t, 32>>(cert_dele_v, "PUBK");
189 const auto sig = get<std::array<uint8_t, 64>>(response_v, "SIG");
190 if(!verify_signature(cert_dele_pubk, srep, sig))
191 { throw Roughtime_Error("Response signature invalid"); }
192
193 const auto indx = get<uint32_t>(response_v, "INDX");
194 const auto path = get_v(response_v, "PATH");
195 const auto srep_root = get<std::array<uint8_t, 64>>(srep_v, "ROOT");
196 const auto size = path.size();
197 const auto levels = size/64;
198
199 if(size % 64)
200 { throw Roughtime_Error("Merkle tree path size must be multiple of 64 bytes"); }
201 if(indx >= (1u << levels))
202 { throw Roughtime_Error("Merkle tree path is too short"); }
203
204 auto hash = hashLeaf(nonce.get_nonce());
205 auto index = indx;
206 auto level = 0u;
207 while(level < levels)
208 {
209 hashNode(hash, typecast_copy<std::array<uint8_t, 64>>(path.data() + level*64), index&1);
210 ++level;
211 index>>=1;
212 }
213
214 if(srep_root != hash)
215 { throw Roughtime_Error("Nonce verification failed"); }
216
217 const auto cert_dele_maxt = sys_microseconds64(get<microseconds64>(cert_dele_v, "MAXT"));
218 const auto cert_dele_mint = sys_microseconds64(get<microseconds64>(cert_dele_v, "MINT"));
219 const auto srep_midp = sys_microseconds64(get<microseconds64>(srep_v, "MIDP"));
220 const auto srep_radi = get<microseconds32>(srep_v, "RADI");
221 if(srep_midp < cert_dele_mint)
222 { throw Roughtime_Error("Midpoint earlier than delegation start"); }
223 if(srep_midp > cert_dele_maxt)
224 { throw Roughtime_Error("Midpoint later than delegation end"); }
225 return {cert_dele, cert_sig, srep_midp, srep_radi};
226 }
227
229 {
230 const char context[] = "RoughTime v1 delegation signature--";
231 PK_Verifier verifier(pk, "Pure");
232 verifier.update(cast_char_ptr_to_uint8(context), sizeof(context)); //add context including \0
233 verifier.update(m_cert_dele.data(), m_cert_dele.size());
234 return verifier.check_signature(m_cert_sig.data(), m_cert_sig.size());
235 }
236
237Nonce nonce_from_blind(const std::vector<uint8_t>& previous_response,
238 const Nonce& blind)
239 {
240 std::array<uint8_t, 64> ret;
241 const auto blind_arr = blind.get_nonce();
242 std::unique_ptr<Botan::HashFunction> hash(Botan::HashFunction::create_or_throw("SHA-512"));
243 hash->update(previous_response);
244 hash->update(hash->final());
245 hash->update(blind_arr.data(), blind_arr.size());
246 hash->final(ret.data());
247
248 return ret;
249 }
250
251Chain::Chain(const std::string& str)
252 {
253 std::stringstream ss(str);
254 const std::string ERROR_MESSAGE = "Line does not have 4 space separated fields";
255 for(std::string s; std::getline(ss, s);)
256 {
257 size_t start = 0, end = 0;
258 end = s.find(' ', start);
259 if(end == std::string::npos)
260 {
261 throw Decoding_Error(ERROR_MESSAGE);
262 }
263 const auto publicKeyType = s.substr(start, end-start);
264 if(publicKeyType != "ed25519")
265 { throw Not_Implemented("Only ed25519 publicKeyType is implemented"); }
266
267 start = end + 1;
268 end = s.find(' ', start);
269 if(end == std::string::npos)
270 {
271 throw Decoding_Error(ERROR_MESSAGE);
272 }
273 const auto serverPublicKey = Botan::Ed25519_PublicKey(Botan::base64_decode(s.substr(start, end-start)));
274
275 start = end + 1;
276 end = s.find(' ', start);
277 if(end == std::string::npos)
278 {
279 throw Decoding_Error(ERROR_MESSAGE);
280 }
281 if((end - start) != 88)
282 {
283 throw Decoding_Error("Nonce has invalid length");
284 }
285 const auto vec = Botan::base64_decode(s.substr(start, end-start));
286 const auto nonceOrBlind = Nonce(vector_to_array<64>(Botan::base64_decode(s.substr(start, end-start))));
287
288 start = end + 1;
289 end = s.find(' ', start);
290 if(end != std::string::npos)
291 {
292 throw Decoding_Error(ERROR_MESSAGE);
293 }
294 const auto response = Botan::unlock(Botan::base64_decode(s.substr(start)));
295
296 m_links.push_back({response, serverPublicKey, nonceOrBlind});
297 }
298 }
299std::vector<Response> Chain::responses() const
300 {
301 std::vector<Response> responses;
302 for(unsigned i = 0; i < m_links.size(); ++i)
303 {
304 const auto& l = m_links[i];
305 const auto nonce = i ? nonce_from_blind(m_links[i-1].response(), l.nonce_or_blind()) : l.nonce_or_blind();
306 const auto response = Response::from_bits(l.response(), nonce);
307 if(!response.validate(l.public_key()))
308 { throw Roughtime_Error("Invalid signature or public key"); }
309 responses.push_back(response);
310 }
311 return responses;
312 }
313Nonce Chain::next_nonce(const Nonce& blind) const
314 {
315 return m_links.empty()
316 ? blind
317 : nonce_from_blind(m_links.back().response(), blind);
318 }
319void Chain::append(const Link& new_link, size_t max_chain_size)
320 {
321 if(max_chain_size <= 0)
322 { throw Invalid_Argument("Max chain size must be positive"); }
323
324 while(m_links.size() >= max_chain_size)
325 {
326 if(m_links.size() == 1)
327 {
328 auto new_link_updated = new_link;
329 new_link_updated.nonce_or_blind() =
330 nonce_from_blind(m_links[0].response(), new_link.nonce_or_blind()); //we need to convert blind to nonce
331 m_links.clear();
332 m_links.push_back(new_link_updated);
333 return;
334 }
335 if(m_links.size() >= 2)
336 {
337 m_links[1].nonce_or_blind() =
338 nonce_from_blind(m_links[0].response(), m_links[1].nonce_or_blind()); //we need to convert blind to nonce
339 }
340 m_links.erase(m_links.begin());
341 }
342 m_links.push_back(new_link);
343 }
344
345std::string Chain::to_string() const
346 {
347 std::string s;
348 s.reserve((7+1 + 88+1 + 44+1 + 480)*m_links.size());
349 for(const auto& link : m_links)
350 {
351 s += "ed25519";
352 s += ' ';
353 s += Botan::base64_encode(link.public_key().get_public_key());
354 s += ' ';
355 s += Botan::base64_encode(link.nonce_or_blind().get_nonce().data(), link.nonce_or_blind().get_nonce().size());
356 s += ' ';
357 s += Botan::base64_encode(link.response());
358 s += '\n';
359 }
360 return s;
361 }
362
363std::vector<uint8_t> online_request(const std::string& uri,
364 const Nonce& nonce,
365 std::chrono::milliseconds timeout)
366 {
367 const std::chrono::system_clock::time_point start_time = std::chrono::system_clock::now();
368 auto socket = OS::open_socket_udp(uri, timeout);
369 if(!socket)
370 { throw Not_Implemented("No socket support enabled in build"); }
371
372 const auto encoded = encode_request(nonce);
373 socket->write(encoded.data(), encoded.size());
374
375 if(std::chrono::system_clock::now() - start_time > timeout)
376 { throw System_Error("Timeout during socket write"); }
377
378 std::vector<uint8_t> buffer;
379 buffer.resize(360+64*10+1); //response basic size is 360 bytes + 64 bytes for each level of merkle tree
380 //add one additional byte to be able to differentiate if datagram got truncated
381 const auto n = socket->read(buffer.data(), buffer.size());
382
383 if(!n || std::chrono::system_clock::now() - start_time > timeout)
384 { throw System_Error("Timeout waiting for response"); }
385
386 if(n == buffer.size())
387 { throw System_Error("Buffer too small"); }
388
389 buffer.resize(n);
390 return buffer;
391 }
392
393std::vector<Server_Information> servers_from_str(const std::string& str)
394 {
395 std::vector<Server_Information> servers;
396 std::stringstream ss(str);
397 const std::string ERROR_MESSAGE = "Line does not have at least 5 space separated fields";
398 for(std::string s; std::getline(ss, s);)
399 {
400 size_t start = 0, end = 0;
401 end = s.find(' ', start);
402 if(end == std::string::npos)
403 {
404 throw Decoding_Error(ERROR_MESSAGE);
405 }
406 const auto name = s.substr(start, end-start);
407
408 start = end + 1;
409 end = s.find(' ', start);
410 if(end == std::string::npos)
411 {
412 throw Decoding_Error(ERROR_MESSAGE);
413 }
414 const auto publicKeyType = s.substr(start, end-start);
415 if(publicKeyType != "ed25519")
416 { throw Not_Implemented("Only ed25519 publicKeyType is implemented"); }
417
418 start = end + 1;
419 end = s.find(' ', start);
420
421 if(end == std::string::npos)
422 {
423 throw Decoding_Error(ERROR_MESSAGE);
424 }
425 const auto publicKeyBase64 = s.substr(start, end-start);
426 const auto publicKey = Botan::Ed25519_PublicKey(Botan::base64_decode(publicKeyBase64));
427
428 start = end + 1;
429 end = s.find(' ', start);
430 if(end == std::string::npos)
431 {
432 throw Decoding_Error(ERROR_MESSAGE);
433 }
434 const auto protocol = s.substr(start, end-start);
435 if(protocol != "udp")
436 { throw Not_Implemented("Only UDP protocol is implemented"); }
437
438 const auto addresses = [&]()
439 {
440 std::vector<std::string> addr;
441 for(;;)
442 {
443 start = end + 1;
444 end = s.find(' ', start);
445 const auto address = s.substr(start, (end == std::string::npos) ? std::string::npos : end-start);
446 if(address.empty())
447 { return addr; }
448 addr.push_back(address);
449 if(end == std::string::npos)
450 { return addr; }
451 }
452 }
453 ();
454 if(addresses.size() == 0)
455 {
456 throw Decoding_Error(ERROR_MESSAGE);
457 }
458
459 servers.push_back({name, publicKey, std::move(addresses)});
460 }
461 return servers;
462 }
463
464}
465
466}
static std::unique_ptr< HashFunction > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition: hash.cpp:344
void update(uint8_t in)
Definition: pubkey.h:347
bool check_signature(const uint8_t sig[], size_t length)
Definition: pubkey.cpp:343
virtual void randomize(uint8_t output[], size_t length)=0
void append(const Link &new_link, size_t max_chain_size)
Definition: roughtime.cpp:319
std::string to_string() const
Definition: roughtime.cpp:345
Nonce next_nonce(const Nonce &blind) const
Definition: roughtime.cpp:313
std::vector< Response > responses() const
Definition: roughtime.cpp:299
const std::array< uint8_t, 64 > & get_nonce() const
Definition: roughtime.h:43
std::chrono::time_point< std::chrono::system_clock, microseconds64 > sys_microseconds64
Definition: roughtime.h:63
static Response from_bits(const std::vector< uint8_t > &response, const Nonce &nonce)
Definition: roughtime.cpp:177
bool validate(const Ed25519_PublicKey &pk) const
Definition: roughtime.cpp:228
std::string name
fe T
Definition: ge.cpp:37
std::unique_ptr< SocketUDP > BOTAN_TEST_API open_socket_udp(const std::string &hostname, const std::string &service, std::chrono::microseconds timeout)
Definition: socket_udp.cpp:318
std::vector< uint8_t > online_request(const std::string &uri, const Nonce &nonce, std::chrono::milliseconds timeout)
Definition: roughtime.cpp:363
std::vector< Server_Information > servers_from_str(const std::string &str)
Definition: roughtime.cpp:393
Nonce nonce_from_blind(const std::vector< uint8_t > &previous_response, const Nonce &blind)
Definition: roughtime.cpp:237
std::array< uint8_t, request_min_size > encode_request(const Nonce &nonce)
Definition: roughtime.cpp:169
const unsigned request_min_size
Definition: roughtime.h:23
Definition: alg_id.cpp:13
size_t base64_encode(char out[], const uint8_t in[], size_t input_length, size_t &input_consumed, bool final_inputs)
Definition: base64.cpp:185
size_t base64_decode(uint8_t out[], const char in[], size_t input_length, size_t &input_consumed, bool final_inputs, bool ignore_ws)
Definition: base64.cpp:200
std::vector< T > unlock(const secure_vector< T > &in)
Definition: secmem.h:72
void typecast_copy(uint8_t out[], T in[], size_t N)
Definition: mem_ops.h:145
const char * cast_uint8_ptr_to_char(const uint8_t *b)
Definition: mem_ops.h:195
const uint8_t * cast_char_ptr_to_uint8(const char *s)
Definition: mem_ops.h:190
Definition: bigint.h:1143
MechanismType hash
MechanismType type