1 /* ====================================================================
2 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * [email protected].
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This product includes cryptographic software written by Eric Young
50 * ([email protected]). This product includes software written by Tim
51 * Hudson ([email protected]). */
52
53 #include <openssl/ecdsa.h>
54
55 #include <vector>
56
57 #include <gtest/gtest.h>
58
59 #include <openssl/bn.h>
60 #include <openssl/crypto.h>
61 #include <openssl/ec.h>
62 #include <openssl/err.h>
63 #include <openssl/mem.h>
64 #include <openssl/nid.h>
65 #include <openssl/rand.h>
66
67 #include "../ec/internal.h"
68 #include "../../test/file_test.h"
69 #include "../../test/test_util.h"
70
71
HexToBIGNUM(const char * hex)72 static bssl::UniquePtr<BIGNUM> HexToBIGNUM(const char *hex) {
73 BIGNUM *bn = nullptr;
74 BN_hex2bn(&bn, hex);
75 return bssl::UniquePtr<BIGNUM>(bn);
76 }
77
78 // Though we do not support secp160r1, it is reachable from the deprecated
79 // custom curve APIs and has some unique properties (n is larger than p with the
80 // difference crossing a word boundary on 32-bit), so test it explicitly.
NewSecp160r1Group()81 static bssl::UniquePtr<EC_GROUP> NewSecp160r1Group() {
82 static const char kP[] = "ffffffffffffffffffffffffffffffff7fffffff";
83 static const char kA[] = "ffffffffffffffffffffffffffffffff7ffffffc";
84 static const char kB[] = "1c97befc54bd7a8b65acf89f81d4d4adc565fa45";
85 static const char kX[] = "4a96b5688ef573284664698968c38bb913cbfc82";
86 static const char kY[] = "23a628553168947d59dcc912042351377ac5fb32";
87 static const char kN[] = "0100000000000000000001f4c8f927aed3ca752257";
88
89 bssl::UniquePtr<BIGNUM> p = HexToBIGNUM(kP), a = HexToBIGNUM(kA),
90 b = HexToBIGNUM(kB), x = HexToBIGNUM(kX),
91 y = HexToBIGNUM(kY), n = HexToBIGNUM(kN);
92 if (!p || !a || !b || !x || !y || !n) {
93 return nullptr;
94 }
95
96 bssl::UniquePtr<EC_GROUP> group(
97 EC_GROUP_new_curve_GFp(p.get(), a.get(), b.get(), nullptr));
98 if (!group) {
99 return nullptr;
100 }
101 bssl::UniquePtr<EC_POINT> g(EC_POINT_new(group.get()));
102 if (!g ||
103 !EC_POINT_set_affine_coordinates_GFp(group.get(), g.get(), x.get(),
104 y.get(), nullptr) ||
105 !EC_GROUP_set_generator(group.get(), g.get(), n.get(), BN_value_one())) {
106 return nullptr;
107 }
108 return group;
109 }
110
111 enum API {
112 kEncodedAPI,
113 kRawAPI,
114 };
115
116 // VerifyECDSASig checks that verifying |ecdsa_sig| gives |expected_result|.
VerifyECDSASig(API api,const uint8_t * digest,size_t digest_len,const ECDSA_SIG * ecdsa_sig,EC_KEY * eckey,int expected_result)117 static void VerifyECDSASig(API api, const uint8_t *digest, size_t digest_len,
118 const ECDSA_SIG *ecdsa_sig, EC_KEY *eckey,
119 int expected_result) {
120 switch (api) {
121 case kEncodedAPI: {
122 uint8_t *der;
123 size_t der_len;
124 ASSERT_TRUE(ECDSA_SIG_to_bytes(&der, &der_len, ecdsa_sig));
125 bssl::UniquePtr<uint8_t> delete_der(der);
126 EXPECT_EQ(expected_result,
127 ECDSA_verify(0, digest, digest_len, der, der_len, eckey));
128 break;
129 }
130
131 case kRawAPI:
132 EXPECT_EQ(expected_result,
133 ECDSA_do_verify(digest, digest_len, ecdsa_sig, eckey));
134 break;
135
136 default:
137 FAIL() << "Unknown API type.";
138 }
139 }
140
141 // TestTamperedSig verifies that signature verification fails when a valid
142 // signature is tampered with. |ecdsa_sig| must be a valid signature, which will
143 // be modified.
TestTamperedSig(API api,const uint8_t * digest,size_t digest_len,ECDSA_SIG * ecdsa_sig,EC_KEY * eckey,const BIGNUM * order)144 static void TestTamperedSig(API api, const uint8_t *digest,
145 size_t digest_len, ECDSA_SIG *ecdsa_sig,
146 EC_KEY *eckey, const BIGNUM *order) {
147 SCOPED_TRACE(api);
148 // Modify a single byte of the signature: to ensure we don't
149 // garble the ASN1 structure, we read the raw signature and
150 // modify a byte in one of the bignums directly.
151
152 // Store the two BIGNUMs in raw_buf.
153 size_t r_len = BN_num_bytes(ecdsa_sig->r);
154 size_t s_len = BN_num_bytes(ecdsa_sig->s);
155 size_t bn_len = BN_num_bytes(order);
156 ASSERT_LE(r_len, bn_len);
157 ASSERT_LE(s_len, bn_len);
158 size_t buf_len = 2 * bn_len;
159 std::vector<uint8_t> raw_buf(buf_len);
160 // Pad the bignums with leading zeroes.
161 ASSERT_TRUE(BN_bn2bin_padded(raw_buf.data(), bn_len, ecdsa_sig->r));
162 ASSERT_TRUE(BN_bn2bin_padded(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
163
164 // Modify a single byte in the buffer.
165 size_t offset = raw_buf[10] % buf_len;
166 uint8_t dirt = raw_buf[11] ? raw_buf[11] : 1;
167 raw_buf[offset] ^= dirt;
168 // Now read the BIGNUMs back in from raw_buf.
169 ASSERT_TRUE(BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r));
170 ASSERT_TRUE(BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
171 VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 0);
172
173 // Sanity check: Undo the modification and verify signature.
174 raw_buf[offset] ^= dirt;
175 ASSERT_TRUE(BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r));
176 ASSERT_TRUE(BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
177 VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 1);
178 }
179
TEST(ECDSATest,BuiltinCurves)180 TEST(ECDSATest, BuiltinCurves) {
181 // Fill digest values with some random data.
182 uint8_t digest[20], wrong_digest[20];
183 ASSERT_TRUE(RAND_bytes(digest, 20));
184 CONSTTIME_DECLASSIFY(digest, 20);
185 ASSERT_TRUE(RAND_bytes(wrong_digest, 20));
186 CONSTTIME_DECLASSIFY(wrong_digest, 20);
187
188 static const struct {
189 int nid;
190 const char *name;
191 } kCurves[] = {
192 { NID_secp224r1, "secp224r1" },
193 { NID_X9_62_prime256v1, "secp256r1" },
194 { NID_secp384r1, "secp384r1" },
195 { NID_secp521r1, "secp521r1" },
196 { NID_secp160r1, "secp160r1" },
197 };
198
199 for (const auto &curve : kCurves) {
200 SCOPED_TRACE(curve.name);
201
202 bssl::UniquePtr<EC_GROUP> group;
203 if (curve.nid == NID_secp160r1) {
204 group = NewSecp160r1Group();
205 } else {
206 group.reset(EC_GROUP_new_by_curve_name(curve.nid));
207 }
208 ASSERT_TRUE(group);
209 const BIGNUM *order = EC_GROUP_get0_order(group.get());
210
211 // Create a new ECDSA key.
212 bssl::UniquePtr<EC_KEY> eckey(EC_KEY_new());
213 ASSERT_TRUE(eckey);
214 ASSERT_TRUE(EC_KEY_set_group(eckey.get(), group.get()));
215 ASSERT_TRUE(EC_KEY_generate_key(eckey.get()));
216
217 // Create a second key.
218 bssl::UniquePtr<EC_KEY> wrong_eckey(EC_KEY_new());
219 ASSERT_TRUE(wrong_eckey);
220 ASSERT_TRUE(EC_KEY_set_group(wrong_eckey.get(), group.get()));
221 ASSERT_TRUE(EC_KEY_generate_key(wrong_eckey.get()));
222
223 // Check the key.
224 EXPECT_TRUE(EC_KEY_check_key(eckey.get()));
225
226 // Test ASN.1-encoded signatures.
227 // Create a signature.
228 std::vector<uint8_t> signature(ECDSA_size(eckey.get()));
229 unsigned sig_len;
230 ASSERT_TRUE(
231 ECDSA_sign(0, digest, 20, signature.data(), &sig_len, eckey.get()));
232 signature.resize(sig_len);
233
234 // ECDSA signing should be non-deterministic. This does not verify k is
235 // generated securely but at least checks it was randomized at all.
236 std::vector<uint8_t> signature2(ECDSA_size(eckey.get()));
237 ASSERT_TRUE(
238 ECDSA_sign(0, digest, 20, signature2.data(), &sig_len, eckey.get()));
239 signature2.resize(sig_len);
240 EXPECT_NE(Bytes(signature), Bytes(signature2));
241
242 // Verify the signature.
243 EXPECT_TRUE(ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
244 eckey.get()));
245
246 // Verify the signature with the wrong key.
247 EXPECT_FALSE(ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
248 wrong_eckey.get()));
249 ERR_clear_error();
250
251 // Verify the signature using the wrong digest.
252 EXPECT_FALSE(ECDSA_verify(0, wrong_digest, 20, signature.data(),
253 signature.size(), eckey.get()));
254 ERR_clear_error();
255
256 // Verify a truncated signature.
257 EXPECT_FALSE(ECDSA_verify(0, digest, 20, signature.data(),
258 signature.size() - 1, eckey.get()));
259 ERR_clear_error();
260
261 // Verify a tampered signature.
262 bssl::UniquePtr<ECDSA_SIG> ecdsa_sig(
263 ECDSA_SIG_from_bytes(signature.data(), signature.size()));
264 ASSERT_TRUE(ecdsa_sig);
265 TestTamperedSig(kEncodedAPI, digest, 20, ecdsa_sig.get(), eckey.get(),
266 order);
267
268 // Test ECDSA_SIG signing and verification.
269 // Create a signature.
270 ecdsa_sig.reset(ECDSA_do_sign(digest, 20, eckey.get()));
271 ASSERT_TRUE(ecdsa_sig);
272
273 // Verify the signature using the correct key.
274 EXPECT_TRUE(ECDSA_do_verify(digest, 20, ecdsa_sig.get(), eckey.get()));
275
276 // Verify the signature with the wrong key.
277 EXPECT_FALSE(
278 ECDSA_do_verify(digest, 20, ecdsa_sig.get(), wrong_eckey.get()));
279 ERR_clear_error();
280
281 // Verify the signature using the wrong digest.
282 EXPECT_FALSE(
283 ECDSA_do_verify(wrong_digest, 20, ecdsa_sig.get(), eckey.get()));
284 ERR_clear_error();
285
286 // Verify a tampered signature.
287 TestTamperedSig(kRawAPI, digest, 20, ecdsa_sig.get(), eckey.get(), order);
288 }
289 }
290
BitsToBytes(size_t bits)291 static size_t BitsToBytes(size_t bits) {
292 return (bits / 8) + (7 + (bits % 8)) / 8;
293 }
294
TEST(ECDSATest,MaxSigLen)295 TEST(ECDSATest, MaxSigLen) {
296 static const size_t kBits[] = {224, 256, 384, 521, 10000};
297 for (size_t bits : kBits) {
298 SCOPED_TRACE(bits);
299 size_t order_len = BitsToBytes(bits);
300
301 // Create the largest possible |ECDSA_SIG| of the given constraints.
302 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
303 ASSERT_TRUE(sig);
304 std::vector<uint8_t> bytes(order_len, 0xff);
305 ASSERT_TRUE(BN_bin2bn(bytes.data(), bytes.size(), sig->r));
306 ASSERT_TRUE(BN_bin2bn(bytes.data(), bytes.size(), sig->s));
307 // Serialize it.
308 uint8_t *der;
309 size_t der_len;
310 ASSERT_TRUE(ECDSA_SIG_to_bytes(&der, &der_len, sig.get()));
311 OPENSSL_free(der);
312
313 EXPECT_EQ(der_len, ECDSA_SIG_max_len(order_len));
314 }
315 }
316
GetCurve(FileTest * t,const char * key)317 static bssl::UniquePtr<EC_GROUP> GetCurve(FileTest *t, const char *key) {
318 std::string curve_name;
319 if (!t->GetAttribute(&curve_name, key)) {
320 return nullptr;
321 }
322
323 if (curve_name == "P-224") {
324 return bssl::UniquePtr<EC_GROUP>(const_cast<EC_GROUP *>(EC_group_p224()));
325 }
326 if (curve_name == "P-256") {
327 return bssl::UniquePtr<EC_GROUP>(const_cast<EC_GROUP *>(EC_group_p256()));
328 }
329 if (curve_name == "P-384") {
330 return bssl::UniquePtr<EC_GROUP>(const_cast<EC_GROUP *>(EC_group_p384()));
331 }
332 if (curve_name == "P-521") {
333 return bssl::UniquePtr<EC_GROUP>(const_cast<EC_GROUP *>(EC_group_p521()));
334 }
335 if (curve_name == "secp160r1") {
336 return NewSecp160r1Group();
337 }
338
339 ADD_FAILURE() << "Unknown curve: " << curve_name;
340 return nullptr;
341 }
342
MakeCustomClone(const EC_GROUP * group)343 static bssl::UniquePtr<EC_GROUP> MakeCustomClone(const EC_GROUP *group) {
344 bssl::UniquePtr<BN_CTX> ctx(BN_CTX_new());
345 bssl::UniquePtr<BIGNUM> p(BN_new()), a(BN_new()), b(BN_new()), x(BN_new()),
346 y(BN_new());
347 if (!ctx || !p || !a || !b || !x || !y ||
348 !EC_GROUP_get_curve_GFp(group, p.get(), a.get(), b.get(), ctx.get()) ||
349 !EC_POINT_get_affine_coordinates_GFp(
350 group, EC_GROUP_get0_generator(group), x.get(), y.get(), ctx.get())) {
351 return nullptr;
352 }
353 bssl::UniquePtr<EC_GROUP> ret(
354 EC_GROUP_new_curve_GFp(p.get(), a.get(), b.get(), ctx.get()));
355 if (!ret) {
356 return nullptr;
357 }
358 bssl::UniquePtr<EC_POINT> g(EC_POINT_new(ret.get()));
359 if (!g ||
360 !EC_POINT_set_affine_coordinates_GFp(ret.get(), g.get(), x.get(), y.get(),
361 ctx.get()) ||
362 !EC_GROUP_set_generator(ret.get(), g.get(), EC_GROUP_get0_order(group),
363 BN_value_one())) {
364 return nullptr;
365 }
366 return ret;
367 }
368
GetBIGNUM(FileTest * t,const char * key)369 static bssl::UniquePtr<BIGNUM> GetBIGNUM(FileTest *t, const char *key) {
370 std::vector<uint8_t> bytes;
371 if (!t->GetBytes(&bytes, key)) {
372 return nullptr;
373 }
374
375 return bssl::UniquePtr<BIGNUM>(BN_bin2bn(bytes.data(), bytes.size(), nullptr));
376 }
377
TEST(ECDSATest,VerifyTestVectors)378 TEST(ECDSATest, VerifyTestVectors) {
379 FileTestGTest("crypto/fipsmodule/ecdsa/ecdsa_verify_tests.txt",
380 [](FileTest *t) {
381 for (bool custom_group : {false, true}) {
382 SCOPED_TRACE(custom_group);
383 bssl::UniquePtr<EC_GROUP> group = GetCurve(t, "Curve");
384 ASSERT_TRUE(group);
385 if (custom_group) {
386 group = MakeCustomClone(group.get());
387 ASSERT_TRUE(group);
388 }
389 bssl::UniquePtr<BIGNUM> x = GetBIGNUM(t, "X");
390 ASSERT_TRUE(x);
391 bssl::UniquePtr<BIGNUM> y = GetBIGNUM(t, "Y");
392 ASSERT_TRUE(y);
393 bssl::UniquePtr<BIGNUM> r = GetBIGNUM(t, "R");
394 ASSERT_TRUE(r);
395 bssl::UniquePtr<BIGNUM> s = GetBIGNUM(t, "S");
396 ASSERT_TRUE(s);
397 std::vector<uint8_t> digest;
398 ASSERT_TRUE(t->GetBytes(&digest, "Digest"));
399
400 bssl::UniquePtr<EC_KEY> key(EC_KEY_new());
401 ASSERT_TRUE(key);
402 bssl::UniquePtr<EC_POINT> pub_key(EC_POINT_new(group.get()));
403 ASSERT_TRUE(pub_key);
404 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
405 ASSERT_TRUE(sig);
406 ASSERT_TRUE(EC_KEY_set_group(key.get(), group.get()));
407 ASSERT_TRUE(EC_POINT_set_affine_coordinates_GFp(
408 group.get(), pub_key.get(), x.get(), y.get(), nullptr));
409 ASSERT_TRUE(EC_KEY_set_public_key(key.get(), pub_key.get()));
410 ASSERT_TRUE(BN_copy(sig->r, r.get()));
411 ASSERT_TRUE(BN_copy(sig->s, s.get()));
412
413 EXPECT_EQ(
414 t->HasAttribute("Invalid") ? 0 : 1,
415 ECDSA_do_verify(digest.data(), digest.size(), sig.get(), key.get()));
416 }
417 });
418 }
419
TEST(ECDSATest,SignTestVectors)420 TEST(ECDSATest, SignTestVectors) {
421 FileTestGTest("crypto/fipsmodule/ecdsa/ecdsa_sign_tests.txt",
422 [](FileTest *t) {
423 for (bool custom_group : {false, true}) {
424 SCOPED_TRACE(custom_group);
425 bssl::UniquePtr<EC_GROUP> group = GetCurve(t, "Curve");
426 ASSERT_TRUE(group);
427 if (custom_group) {
428 group = MakeCustomClone(group.get());
429 ASSERT_TRUE(group);
430 }
431 bssl::UniquePtr<BIGNUM> priv_key = GetBIGNUM(t, "Private");
432 ASSERT_TRUE(priv_key);
433 bssl::UniquePtr<BIGNUM> x = GetBIGNUM(t, "X");
434 ASSERT_TRUE(x);
435 bssl::UniquePtr<BIGNUM> y = GetBIGNUM(t, "Y");
436 ASSERT_TRUE(y);
437 std::vector<uint8_t> k;
438 ASSERT_TRUE(t->GetBytes(&k, "K"));
439 bssl::UniquePtr<BIGNUM> r = GetBIGNUM(t, "R");
440 ASSERT_TRUE(r);
441 bssl::UniquePtr<BIGNUM> s = GetBIGNUM(t, "S");
442 ASSERT_TRUE(s);
443 std::vector<uint8_t> digest;
444 ASSERT_TRUE(t->GetBytes(&digest, "Digest"));
445
446 bssl::UniquePtr<EC_KEY> key(EC_KEY_new());
447 ASSERT_TRUE(key);
448 bssl::UniquePtr<EC_POINT> pub_key(EC_POINT_new(group.get()));
449 ASSERT_TRUE(pub_key);
450 ASSERT_TRUE(EC_KEY_set_group(key.get(), group.get()));
451 ASSERT_TRUE(EC_KEY_set_private_key(key.get(), priv_key.get()));
452 ASSERT_TRUE(EC_POINT_set_affine_coordinates_GFp(
453 group.get(), pub_key.get(), x.get(), y.get(), nullptr));
454 ASSERT_TRUE(EC_KEY_set_public_key(key.get(), pub_key.get()));
455 ASSERT_TRUE(EC_KEY_check_key(key.get()));
456
457 bssl::UniquePtr<ECDSA_SIG> sig(
458 ECDSA_sign_with_nonce_and_leak_private_key_for_testing(
459 digest.data(), digest.size(), key.get(), k.data(), k.size()));
460 ASSERT_TRUE(sig);
461
462 EXPECT_EQ(0, BN_cmp(r.get(), sig->r));
463 EXPECT_EQ(0, BN_cmp(s.get(), sig->s));
464 }
465 });
466 }
467