13210394651

Committed 08 Feb 2025 12:33AM UTC coverage: 91.656% (-0.006%) from 91.662%

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Merge pull request #4642 from randombit/jack/target-info-header

Add internal target_info.h header

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87.96

/src/lib/pubkey/ecdsa/ecdsa.cpp

/*
* ECDSA implemenation
* (C) 2007 Manuel Hartl, FlexSecure GmbH
*     2007 Falko Strenzke, FlexSecure GmbH
*     2008-2010,2015,2016,2018,2024 Jack Lloyd
*     2016 René Korthaus
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/ecdsa.h>

#include <botan/internal/keypair.h>
#include <botan/internal/pk_ops_impl.h>

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
   #include <botan/internal/rfc6979.h>
#endif

namespace Botan {

namespace {

EC_AffinePoint recover_ecdsa_public_key(
   const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) {
   if(group.has_cofactor()) {
      throw Invalid_Argument("ECDSA public key recovery only supported for prime order groups");
   }

   if(v >= 4) {
      throw Invalid_Argument("Unexpected v param for ECDSA public key recovery");
   }

   const BigInt& group_order = group.get_order();

   if(r <= 0 || r >= group_order || s <= 0 || s >= group_order) {
      throw Invalid_Argument("Out of range r/s cannot recover ECDSA public key");
   }

   const uint8_t y_odd = v % 2;
   const uint8_t add_order = v >> 1;
   const size_t p_bytes = group.get_p_bytes();

   BigInt x = r;

   if(add_order) {
      x += group_order;
   }

   if(x.bytes() <= p_bytes) {
      std::vector<uint8_t> X(p_bytes + 1);

      X[0] = 0x02 | y_odd;
      x.serialize_to(std::span{X}.subspan(1));

      if(auto R = EC_AffinePoint::deserialize(group, X)) {
         // Compute r_inv * (-eG + s*R)
         const auto ne = EC_Scalar::from_bytes_with_trunc(group, msg).negate();
         const auto ss = EC_Scalar::from_bigint(group, s);

         const auto r_inv = EC_Scalar::from_bigint(group, r).invert_vartime();

         EC_Group::Mul2Table GR_mul(R.value());
         if(auto egsr = GR_mul.mul2_vartime(ne * r_inv, ss * r_inv)) {
            return egsr.value();
         }
      }
   }

   throw Decoding_Error("Failed to recover ECDSA public key from signature/msg pair");
}

}  // namespace

ECDSA_PublicKey::ECDSA_PublicKey(
   const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) :
      EC_PublicKey(group, recover_ecdsa_public_key(group, msg, r, s, v)) {}

std::unique_ptr<Private_Key> ECDSA_PublicKey::generate_another(RandomNumberGenerator& rng) const {
   return std::make_unique<ECDSA_PrivateKey>(rng, domain());
}

uint8_t ECDSA_PublicKey::recovery_param(const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s) const {
   const auto this_key = this->_public_ec_point().serialize_compressed();

   for(uint8_t v = 0; v != 4; ++v) {
      try {
         const auto R = recover_ecdsa_public_key(this->domain(), msg, r, s, v);

         if(R.serialize_compressed() == this_key) {
            return v;
         }
      } catch(Decoding_Error&) {
         // try the next v
      }
   }

   throw Internal_Error("Could not determine ECDSA recovery parameter");
}

std::unique_ptr<Public_Key> ECDSA_PrivateKey::public_key() const {
   return std::make_unique<ECDSA_PublicKey>(domain(), _public_ec_point());
}

bool ECDSA_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const {
   if(!EC_PrivateKey::check_key(rng, strong)) {
      return false;
   }

   if(!strong) {
      return true;
   }

   return KeyPair::signature_consistency_check(rng, *this, "SHA-256");
}

namespace {

/**
* ECDSA signature operation
*/
class ECDSA_Signature_Operation final : public PK_Ops::Signature_with_Hash {
   public:
      ECDSA_Signature_Operation(const ECDSA_PrivateKey& ecdsa, std::string_view padding, RandomNumberGenerator& rng) :
            PK_Ops::Signature_with_Hash(padding),
            m_group(ecdsa.domain()),
            m_x(ecdsa._private_key()),
            m_b(EC_Scalar::random(m_group, rng)),
            m_b_inv(m_b.invert()) {
#if defined(BOTAN_HAS_RFC6979_GENERATOR)
         m_rfc6979 = std::make_unique<RFC6979_Nonce_Generator>(
            this->rfc6979_hash_function(), m_group.get_order_bits(), ecdsa._private_key());
#endif
      }

      size_t signature_length() const override { return 2 * m_group.get_order_bytes(); }

      std::vector<uint8_t> raw_sign(std::span<const uint8_t> msg, RandomNumberGenerator& rng) override;

      AlgorithmIdentifier algorithm_identifier() const override;

   private:
      const EC_Group m_group;
      const EC_Scalar m_x;

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
      std::unique_ptr<RFC6979_Nonce_Generator> m_rfc6979;
#endif

      std::vector<BigInt> m_ws;

      EC_Scalar m_b;
      EC_Scalar m_b_inv;
};

AlgorithmIdentifier ECDSA_Signature_Operation::algorithm_identifier() const {
   const std::string full_name = "ECDSA/" + hash_function();
   const OID oid = OID::from_string(full_name);
   return AlgorithmIdentifier(oid, AlgorithmIdentifier::USE_EMPTY_PARAM);
}

std::vector<uint8_t> ECDSA_Signature_Operation::raw_sign(std::span<const uint8_t> msg, RandomNumberGenerator& rng) {
   const auto m = EC_Scalar::from_bytes_with_trunc(m_group, msg);

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
   const auto k = m_rfc6979->nonce_for(m_group, m);
#else
   const auto k = EC_Scalar::random(m_group, rng);
#endif

   const auto r = EC_Scalar::gk_x_mod_order(k, rng, m_ws);

   // Blind the inversion of k
   const auto k_inv = (m_b * k).invert() * m_b;

   /*
   * Blind the input message and compute x*r+m as (x*r*b + m*b)/b
   */
   m_b.square_self();
   m_b_inv.square_self();

   const auto xr_m = ((m_x * m_b) * r) + (m * m_b);

   const auto s = (k_inv * xr_m) * m_b_inv;

   // With overwhelming probability, a bug rather than actual zero r/s
   if(r.is_zero() || s.is_zero()) {
      throw Internal_Error("During ECDSA signature generated zero r/s");
   }

   return EC_Scalar::serialize_pair(r, s);
}

/**
* ECDSA verification operation
*/
class ECDSA_Verification_Operation final : public PK_Ops::Verification_with_Hash {
   public:
      ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, std::string_view padding) :
            PK_Ops::Verification_with_Hash(padding), m_group(ecdsa.domain()), m_gy_mul(ecdsa._public_ec_point()) {}

      ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, const AlgorithmIdentifier& alg_id) :
            PK_Ops::Verification_with_Hash(alg_id, "ECDSA", true),
            m_group(ecdsa.domain()),
            m_gy_mul(ecdsa._public_ec_point()) {}

      bool verify(std::span<const uint8_t> msg, std::span<const uint8_t> sig) override;

   private:
      const EC_Group m_group;
      const EC_Group::Mul2Table m_gy_mul;
};

bool ECDSA_Verification_Operation::verify(std::span<const uint8_t> msg, std::span<const uint8_t> sig) {
   if(auto rs = EC_Scalar::deserialize_pair(m_group, sig)) {
      const auto& [r, s] = rs.value();

      if(r.is_nonzero() && s.is_nonzero()) {
         const auto m = EC_Scalar::from_bytes_with_trunc(m_group, msg);

         const auto w = s.invert_vartime();

         // Check if r == x_coord(g*w*m + y*w*r) % n
         return m_gy_mul.mul2_vartime_x_mod_order_eq(r, w, m, r);
      }
   }

   return false;
}

}  // namespace

std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_verification_op(std::string_view params,
                                                                              std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Verification_Operation>(*this, params);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_x509_verification_op(
   const AlgorithmIdentifier& signature_algorithm, std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Verification_Operation>(*this, signature_algorithm);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

std::unique_ptr<PK_Ops::Signature> ECDSA_PrivateKey::create_signature_op(RandomNumberGenerator& rng,
                                                                         std::string_view params,
                                                                         std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Signature_Operation>(*this, params, rng);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

}  // namespace Botan

1	/*
2	* ECDSA implemenation
3	* (C) 2007 Manuel Hartl, FlexSecure GmbH
4	* 2007 Falko Strenzke, FlexSecure GmbH
5	* 2008-2010,2015,2016,2018,2024 Jack Lloyd
6	* 2016 René Korthaus
7	*
8	* Botan is released under the Simplified BSD License (see license.txt)
9	*/
10
11	#include <botan/ecdsa.h>
12
13	#include <botan/internal/keypair.h>
14	#include <botan/internal/pk_ops_impl.h>
15
16	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
17	#include <botan/internal/rfc6979.h>
18	#endif
19
20	namespace Botan {
21
22	namespace {
23
24	EC_AffinePoint recover_ecdsa_public_key(	21✔
25	const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) {
26	if(group.has_cofactor()) {	21✔
27	throw Invalid_Argument("ECDSA public key recovery only supported for prime order groups");	×
28	}
29
30	if(v >= 4) {	21✔
31	throw Invalid_Argument("Unexpected v param for ECDSA public key recovery");	×
32	}
33
34	const BigInt& group_order = group.get_order();	21✔
35
36	if(r <= 0 \|\| r >= group_order \|\| s <= 0 \|\| s >= group_order) {	84✔
37	throw Invalid_Argument("Out of range r/s cannot recover ECDSA public key");	×
38	}
39
40	const uint8_t y_odd = v % 2;	21✔
41	const uint8_t add_order = v >> 1;	21✔
42	const size_t p_bytes = group.get_p_bytes();	21✔
43
44	BigInt x = r;	21✔
45
46	if(add_order) {	21✔
47	x += group_order;	×
48	}
49
50	if(x.bytes() <= p_bytes) {	21✔
51	std::vector<uint8_t> X(p_bytes + 1);	21✔
52
53	X[0] = 0x02 \| y_odd;	21✔
54	x.serialize_to(std::span{X}.subspan(1));	21✔
55
56	if(auto R = EC_AffinePoint::deserialize(group, X)) {	21✔
57	// Compute r_inv * (-eG + s*R)
58	const auto ne = EC_Scalar::from_bytes_with_trunc(group, msg).negate();	21✔
59	const auto ss = EC_Scalar::from_bigint(group, s);	21✔
60
61	const auto r_inv = EC_Scalar::from_bigint(group, r).invert_vartime();	21✔
62
63	EC_Group::Mul2Table GR_mul(R.value());	21✔
64	if(auto egsr = GR_mul.mul2_vartime(ne * r_inv, ss * r_inv)) {	21✔
65	return egsr.value();	42✔
66	}	×
67	}	42✔
68	}	×
69
70	throw Decoding_Error("Failed to recover ECDSA public key from signature/msg pair");	×
71	}	42✔
72
73	} // namespace
74
75	ECDSA_PublicKey::ECDSA_PublicKey(	10✔
76	const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) :	10✔
77	EC_PublicKey(group, recover_ecdsa_public_key(group, msg, r, s, v)) {}	10✔
78
79	std::unique_ptr<Private_Key> ECDSA_PublicKey::generate_another(RandomNumberGenerator& rng) const {	28✔
80	return std::make_unique<ECDSA_PrivateKey>(rng, domain());	56✔
81	}
82
83	uint8_t ECDSA_PublicKey::recovery_param(const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s) const {	10✔
84	const auto this_key = this->_public_ec_point().serialize_compressed();	10✔
85
86	for(uint8_t v = 0; v != 4; ++v) {	11✔
87	try {	11✔
88	const auto R = recover_ecdsa_public_key(this->domain(), msg, r, s, v);	11✔
89
90	if(R.serialize_compressed() == this_key) {	22✔
91	return v;	20✔
92	}
93	} catch(Decoding_Error&) {	11✔
94	// try the next v
95	}	×
96	}
97
98	throw Internal_Error("Could not determine ECDSA recovery parameter");	×
99	}	10✔
100
101	std::unique_ptr<Public_Key> ECDSA_PrivateKey::public_key() const {	486✔
102	return std::make_unique<ECDSA_PublicKey>(domain(), _public_ec_point());	486✔
103	}
104
105	bool ECDSA_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const {	32✔
106	if(!EC_PrivateKey::check_key(rng, strong)) {	32✔
107	return false;
108	}
109
110	if(!strong) {	32✔
111	return true;
112	}
113
114	return KeyPair::signature_consistency_check(rng, *this, "SHA-256");	31✔
115	}
116
117	namespace {
118
119	/**
120	* ECDSA signature operation
121	*/
122	class ECDSA_Signature_Operation final : public PK_Ops::Signature_with_Hash {	×
123	public:
124	ECDSA_Signature_Operation(const ECDSA_PrivateKey& ecdsa, std::string_view padding, RandomNumberGenerator& rng) :	578✔
125	PK_Ops::Signature_with_Hash(padding),
126	m_group(ecdsa.domain()),	578✔
127	m_x(ecdsa._private_key()),	578✔
128	m_b(EC_Scalar::random(m_group, rng)),	578✔
129	m_b_inv(m_b.invert()) {	1,156✔
130	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
131	m_rfc6979 = std::make_unique<RFC6979_Nonce_Generator>(	1,734✔
132	this->rfc6979_hash_function(), m_group.get_order_bits(), ecdsa._private_key());	1,156✔
133	#endif
134	}	578✔
135
136	size_t signature_length() const override { return 2 * m_group.get_order_bytes(); }	108✔
137
138	std::vector<uint8_t> raw_sign(std::span<const uint8_t> msg, RandomNumberGenerator& rng) override;
139
140	AlgorithmIdentifier algorithm_identifier() const override;
141
142	private:
143	const EC_Group m_group;
144	const EC_Scalar m_x;
145
146	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
147	std::unique_ptr<RFC6979_Nonce_Generator> m_rfc6979;
148	#endif
149
150	std::vector<BigInt> m_ws;
151
152	EC_Scalar m_b;
153	EC_Scalar m_b_inv;
154	};
155
156	AlgorithmIdentifier ECDSA_Signature_Operation::algorithm_identifier() const {	62✔
157	const std::string full_name = "ECDSA/" + hash_function();	124✔
158	const OID oid = OID::from_string(full_name);	62✔
159	return AlgorithmIdentifier(oid, AlgorithmIdentifier::USE_EMPTY_PARAM);	62✔
160	}	62✔
161
162	std::vector<uint8_t> ECDSA_Signature_Operation::raw_sign(std::span<const uint8_t> msg, RandomNumberGenerator& rng) {	3,122✔
163	const auto m = EC_Scalar::from_bytes_with_trunc(m_group, msg);	3,122✔
164
165	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
166	const auto k = m_rfc6979->nonce_for(m_group, m);	3,122✔
167	#else
168	const auto k = EC_Scalar::random(m_group, rng);
169	#endif
170
171	const auto r = EC_Scalar::gk_x_mod_order(k, rng, m_ws);	3,122✔
172
173	// Blind the inversion of k
174	const auto k_inv = (m_b * k).invert() * m_b;	6,244✔
175
176	/*
177	* Blind the input message and compute xr+m as (xrb + mb)/b
178	*/
179	m_b.square_self();	3,122✔
180	m_b_inv.square_self();	3,122✔
181
182	const auto xr_m = ((m_x * m_b) * r) + (m * m_b);	3,122✔
183
184	const auto s = (k_inv * xr_m) * m_b_inv;	3,122✔
185
186	// With overwhelming probability, a bug rather than actual zero r/s
187	if(r.is_zero() \|\| s.is_zero()) {	3,122✔
188	throw Internal_Error("During ECDSA signature generated zero r/s");	×
189	}
190
191	return EC_Scalar::serialize_pair(r, s);	6,244✔
192	}	3,122✔
193
194	/**
195	* ECDSA verification operation
196	*/
197	class ECDSA_Verification_Operation final : public PK_Ops::Verification_with_Hash {	×
198	public:
199	ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, std::string_view padding) :	12,670✔
200	PK_Ops::Verification_with_Hash(padding), m_group(ecdsa.domain()), m_gy_mul(ecdsa._public_ec_point()) {}	12,670✔
201
202	ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, const AlgorithmIdentifier& alg_id) :	2,830✔
203	PK_Ops::Verification_with_Hash(alg_id, "ECDSA", true),
204	m_group(ecdsa.domain()),	2,830✔
205	m_gy_mul(ecdsa._public_ec_point()) {}	5,660✔
206
207	bool verify(std::span<const uint8_t> msg, std::span<const uint8_t> sig) override;
208
209	private:
210	const EC_Group m_group;
211	const EC_Group::Mul2Table m_gy_mul;
212	};
213
214	bool ECDSA_Verification_Operation::verify(std::span<const uint8_t> msg, std::span<const uint8_t> sig) {	26,829✔
215	if(auto rs = EC_Scalar::deserialize_pair(m_group, sig)) {	26,829✔
216	const auto& [r, s] = rs.value();	22,388✔
217
218	if(r.is_nonzero() && s.is_nonzero()) {	44,776✔
219	const auto m = EC_Scalar::from_bytes_with_trunc(m_group, msg);	22,388✔
220
221	const auto w = s.invert_vartime();	22,388✔
222
223	// Check if r == x_coord(gwm + ywr) % n
224	return m_gy_mul.mul2_vartime_x_mod_order_eq(r, w, m, r);	22,388✔
225	}	22,388✔
226	}	22,388✔
227
228	return false;	4,441✔
229	}
230
231	} // namespace
232
233	std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_verification_op(std::string_view params,	49,372✔
234	std::string_view provider) const {
235	if(provider == "base" \|\| provider.empty()) {	61,616✔
236	return std::make_unique<ECDSA_Verification_Operation>(*this, params);	12,670✔
237	}
238
239	throw Provider_Not_Found(algo_name(), provider);	73,404✔
240	}
241
242	std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_x509_verification_op(	2,830✔
243	const AlgorithmIdentifier& signature_algorithm, std::string_view provider) const {
244	if(provider == "base" \|\| provider.empty()) {	2,830✔
245	return std::make_unique<ECDSA_Verification_Operation>(*this, signature_algorithm);	2,830✔
246	}
247
248	throw Provider_Not_Found(algo_name(), provider);	×
249	}
250
251	std::unique_ptr<PK_Ops::Signature> ECDSA_PrivateKey::create_signature_op(RandomNumberGenerator& rng,	890✔
252	std::string_view params,
253	std::string_view provider) const {
254	if(provider == "base" \|\| provider.empty()) {	996✔
255	return std::make_unique<ECDSA_Signature_Operation>(*this, params, rng);	578✔
256	}
257
258	throw Provider_Not_Found(algo_name(), provider);	624✔
259	}
260
261	} // namespace Botan

randombit / botan / 13210394651

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