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 * openssl-core@OpenSSL.org.
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 * (eay@cryptsoft.com). This product includes software written by Tim
51 * Hudson (tjh@cryptsoft.com). */
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
70
HexToBIGNUM(const char * hex)71 static bssl::UniquePtr<BIGNUM> HexToBIGNUM(const char *hex) {
72 BIGNUM *bn = nullptr;
73 BN_hex2bn(&bn, hex);
74 return bssl::UniquePtr<BIGNUM>(bn);
75 }
76
77 // Though we do not support secp160r1, it is reachable from the deprecated
78 // custom curve APIs and has some unique properties (n is larger than p with the
79 // difference crossing a word boundary on 32-bit), so test it explicitly.
NewSecp160r1Group()80 static bssl::UniquePtr<EC_GROUP> NewSecp160r1Group() {
81 static const char kP[] = "ffffffffffffffffffffffffffffffff7fffffff";
82 static const char kA[] = "ffffffffffffffffffffffffffffffff7ffffffc";
83 static const char kB[] = "1c97befc54bd7a8b65acf89f81d4d4adc565fa45";
84 static const char kX[] = "4a96b5688ef573284664698968c38bb913cbfc82";
85 static const char kY[] = "23a628553168947d59dcc912042351377ac5fb32";
86 static const char kN[] = "0100000000000000000001f4c8f927aed3ca752257";
87
88 bssl::UniquePtr<BIGNUM> p = HexToBIGNUM(kP), a = HexToBIGNUM(kA),
89 b = HexToBIGNUM(kB), x = HexToBIGNUM(kX),
90 y = HexToBIGNUM(kY), n = HexToBIGNUM(kN);
91 if (!p || !a || !b || !x || !y || !n) {
92 return nullptr;
93 }
94
95 bssl::UniquePtr<EC_GROUP> group(
96 EC_GROUP_new_curve_GFp(p.get(), a.get(), b.get(), nullptr));
97 if (!group) {
98 return nullptr;
99 }
100 bssl::UniquePtr<EC_POINT> g(EC_POINT_new(group.get()));
101 if (!g ||
102 !EC_POINT_set_affine_coordinates_GFp(group.get(), g.get(), x.get(),
103 y.get(), nullptr) ||
104 !EC_GROUP_set_generator(group.get(), g.get(), n.get(), BN_value_one())) {
105 return nullptr;
106 }
107 return group;
108 }
109
110 enum API {
111 kEncodedAPI,
112 kRawAPI,
113 };
114
115 // 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)116 static void VerifyECDSASig(API api, const uint8_t *digest, size_t digest_len,
117 const ECDSA_SIG *ecdsa_sig, EC_KEY *eckey,
118 int expected_result) {
119 switch (api) {
120 case kEncodedAPI: {
121 uint8_t *der;
122 size_t der_len;
123 ASSERT_TRUE(ECDSA_SIG_to_bytes(&der, &der_len, ecdsa_sig));
124 bssl::UniquePtr<uint8_t> delete_der(der);
125 EXPECT_EQ(expected_result,
126 ECDSA_verify(0, digest, digest_len, der, der_len, eckey));
127 break;
128 }
129
130 case kRawAPI:
131 EXPECT_EQ(expected_result,
132 ECDSA_do_verify(digest, digest_len, ecdsa_sig, eckey));
133 break;
134
135 default:
136 FAIL() << "Unknown API type.";
137 }
138 }
139
140 // TestTamperedSig verifies that signature verification fails when a valid
141 // signature is tampered with. |ecdsa_sig| must be a valid signature, which will
142 // be modified.
TestTamperedSig(API api,const uint8_t * digest,size_t digest_len,ECDSA_SIG * ecdsa_sig,EC_KEY * eckey,const BIGNUM * order)143 static void TestTamperedSig(API api, const uint8_t *digest,
144 size_t digest_len, ECDSA_SIG *ecdsa_sig,
145 EC_KEY *eckey, const BIGNUM *order) {
146 SCOPED_TRACE(api);
147 // Modify a single byte of the signature: to ensure we don't
148 // garble the ASN1 structure, we read the raw signature and
149 // modify a byte in one of the bignums directly.
150
151 // Store the two BIGNUMs in raw_buf.
152 size_t r_len = BN_num_bytes(ecdsa_sig->r);
153 size_t s_len = BN_num_bytes(ecdsa_sig->s);
154 size_t bn_len = BN_num_bytes(order);
155 ASSERT_LE(r_len, bn_len);
156 ASSERT_LE(s_len, bn_len);
157 size_t buf_len = 2 * bn_len;
158 std::vector<uint8_t> raw_buf(buf_len);
159 // Pad the bignums with leading zeroes.
160 ASSERT_TRUE(BN_bn2bin_padded(raw_buf.data(), bn_len, ecdsa_sig->r));
161 ASSERT_TRUE(BN_bn2bin_padded(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
162
163 // Modify a single byte in the buffer.
164 size_t offset = raw_buf[10] % buf_len;
165 uint8_t dirt = raw_buf[11] ? raw_buf[11] : 1;
166 raw_buf[offset] ^= dirt;
167 // Now read the BIGNUMs back in from raw_buf.
168 ASSERT_TRUE(BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r));
169 ASSERT_TRUE(BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
170 VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 0);
171
172 // Sanity check: Undo the modification and verify signature.
173 raw_buf[offset] ^= dirt;
174 ASSERT_TRUE(BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r));
175 ASSERT_TRUE(BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s));
176 VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 1);
177 }
178
TEST(ECDSATest,BuiltinCurves)179 TEST(ECDSATest, BuiltinCurves) {
180 // Fill digest values with some random data.
181 uint8_t digest[20], wrong_digest[20];
182 ASSERT_TRUE(RAND_bytes(digest, 20));
183 ASSERT_TRUE(RAND_bytes(wrong_digest, 20));
184
185 static const struct {
186 int nid;
187 const char *name;
188 } kCurves[] = {
189 { NID_secp224r1, "secp224r1" },
190 { NID_X9_62_prime256v1, "secp256r1" },
191 { NID_secp384r1, "secp384r1" },
192 { NID_secp521r1, "secp521r1" },
193 { NID_secp160r1, "secp160r1" },
194 };
195
196 for (const auto &curve : kCurves) {
197 SCOPED_TRACE(curve.name);
198
199 bssl::UniquePtr<EC_GROUP> group;
200 if (curve.nid == NID_secp160r1) {
201 group = NewSecp160r1Group();
202 } else {
203 group.reset(EC_GROUP_new_by_curve_name(curve.nid));
204 }
205 ASSERT_TRUE(group);
206 const BIGNUM *order = EC_GROUP_get0_order(group.get());
207
208 // Create a new ECDSA key.
209 bssl::UniquePtr<EC_KEY> eckey(EC_KEY_new());
210 ASSERT_TRUE(eckey);
211 ASSERT_TRUE(EC_KEY_set_group(eckey.get(), group.get()));
212 ASSERT_TRUE(EC_KEY_generate_key(eckey.get()));
213
214 // Create a second key.
215 bssl::UniquePtr<EC_KEY> wrong_eckey(EC_KEY_new());
216 ASSERT_TRUE(wrong_eckey);
217 ASSERT_TRUE(EC_KEY_set_group(wrong_eckey.get(), group.get()));
218 ASSERT_TRUE(EC_KEY_generate_key(wrong_eckey.get()));
219
220 // Check the key.
221 EXPECT_TRUE(EC_KEY_check_key(eckey.get()));
222
223 // Test ASN.1-encoded signatures.
224 // Create a signature.
225 unsigned sig_len = ECDSA_size(eckey.get());
226 std::vector<uint8_t> signature(sig_len);
227 ASSERT_TRUE(
228 ECDSA_sign(0, digest, 20, signature.data(), &sig_len, eckey.get()));
229 signature.resize(sig_len);
230
231 // Verify the signature.
232 EXPECT_TRUE(ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
233 eckey.get()));
234
235 // Verify the signature with the wrong key.
236 EXPECT_FALSE(ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
237 wrong_eckey.get()));
238 ERR_clear_error();
239
240 // Verify the signature using the wrong digest.
241 EXPECT_FALSE(ECDSA_verify(0, wrong_digest, 20, signature.data(),
242 signature.size(), eckey.get()));
243 ERR_clear_error();
244
245 // Verify a truncated signature.
246 EXPECT_FALSE(ECDSA_verify(0, digest, 20, signature.data(),
247 signature.size() - 1, eckey.get()));
248 ERR_clear_error();
249
250 // Verify a tampered signature.
251 bssl::UniquePtr<ECDSA_SIG> ecdsa_sig(
252 ECDSA_SIG_from_bytes(signature.data(), signature.size()));
253 ASSERT_TRUE(ecdsa_sig);
254 TestTamperedSig(kEncodedAPI, digest, 20, ecdsa_sig.get(), eckey.get(),
255 order);
256
257 // Test ECDSA_SIG signing and verification.
258 // Create a signature.
259 ecdsa_sig.reset(ECDSA_do_sign(digest, 20, eckey.get()));
260 ASSERT_TRUE(ecdsa_sig);
261
262 // Verify the signature using the correct key.
263 EXPECT_TRUE(ECDSA_do_verify(digest, 20, ecdsa_sig.get(), eckey.get()));
264
265 // Verify the signature with the wrong key.
266 EXPECT_FALSE(
267 ECDSA_do_verify(digest, 20, ecdsa_sig.get(), wrong_eckey.get()));
268 ERR_clear_error();
269
270 // Verify the signature using the wrong digest.
271 EXPECT_FALSE(
272 ECDSA_do_verify(wrong_digest, 20, ecdsa_sig.get(), eckey.get()));
273 ERR_clear_error();
274
275 // Verify a tampered signature.
276 TestTamperedSig(kRawAPI, digest, 20, ecdsa_sig.get(), eckey.get(), order);
277 }
278 }
279
BitsToBytes(size_t bits)280 static size_t BitsToBytes(size_t bits) {
281 return (bits / 8) + (7 + (bits % 8)) / 8;
282 }
283
TEST(ECDSATest,MaxSigLen)284 TEST(ECDSATest, MaxSigLen) {
285 static const size_t kBits[] = {224, 256, 384, 521, 10000};
286 for (size_t bits : kBits) {
287 SCOPED_TRACE(bits);
288 size_t order_len = BitsToBytes(bits);
289
290 // Create the largest possible |ECDSA_SIG| of the given constraints.
291 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
292 ASSERT_TRUE(sig);
293 std::vector<uint8_t> bytes(order_len, 0xff);
294 ASSERT_TRUE(BN_bin2bn(bytes.data(), bytes.size(), sig->r));
295 ASSERT_TRUE(BN_bin2bn(bytes.data(), bytes.size(), sig->s));
296 // Serialize it.
297 uint8_t *der;
298 size_t der_len;
299 ASSERT_TRUE(ECDSA_SIG_to_bytes(&der, &der_len, sig.get()));
300 OPENSSL_free(der);
301
302 EXPECT_EQ(der_len, ECDSA_SIG_max_len(order_len));
303 }
304 }
305
GetCurve(FileTest * t,const char * key)306 static bssl::UniquePtr<EC_GROUP> GetCurve(FileTest *t, const char *key) {
307 std::string curve_name;
308 if (!t->GetAttribute(&curve_name, key)) {
309 return nullptr;
310 }
311
312 if (curve_name == "P-224") {
313 return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp224r1));
314 }
315 if (curve_name == "P-256") {
316 return bssl::UniquePtr<EC_GROUP>(
317 EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
318 }
319 if (curve_name == "P-384") {
320 return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp384r1));
321 }
322 if (curve_name == "P-521") {
323 return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp521r1));
324 }
325 if (curve_name == "secp160r1") {
326 return NewSecp160r1Group();
327 }
328
329 ADD_FAILURE() << "Unknown curve: " << curve_name;
330 return nullptr;
331 }
332
MakeCustomClone(const EC_GROUP * group)333 static bssl::UniquePtr<EC_GROUP> MakeCustomClone(const EC_GROUP *group) {
334 bssl::UniquePtr<BN_CTX> ctx(BN_CTX_new());
335 bssl::UniquePtr<BIGNUM> p(BN_new()), a(BN_new()), b(BN_new()), x(BN_new()),
336 y(BN_new());
337 if (!ctx || !p || !a || !b || !x || !y ||
338 !EC_GROUP_get_curve_GFp(group, p.get(), a.get(), b.get(), ctx.get()) ||
339 !EC_POINT_get_affine_coordinates_GFp(
340 group, EC_GROUP_get0_generator(group), x.get(), y.get(), ctx.get())) {
341 return nullptr;
342 }
343 bssl::UniquePtr<EC_GROUP> ret(
344 EC_GROUP_new_curve_GFp(p.get(), a.get(), b.get(), ctx.get()));
345 if (!ret) {
346 return nullptr;
347 }
348 bssl::UniquePtr<EC_POINT> g(EC_POINT_new(ret.get()));
349 if (!g ||
350 !EC_POINT_set_affine_coordinates_GFp(ret.get(), g.get(), x.get(), y.get(),
351 ctx.get()) ||
352 !EC_GROUP_set_generator(ret.get(), g.get(), EC_GROUP_get0_order(group),
353 BN_value_one())) {
354 return nullptr;
355 }
356 return ret;
357 }
358
GetBIGNUM(FileTest * t,const char * key)359 static bssl::UniquePtr<BIGNUM> GetBIGNUM(FileTest *t, const char *key) {
360 std::vector<uint8_t> bytes;
361 if (!t->GetBytes(&bytes, key)) {
362 return nullptr;
363 }
364
365 return bssl::UniquePtr<BIGNUM>(BN_bin2bn(bytes.data(), bytes.size(), nullptr));
366 }
367
TEST(ECDSATest,VerifyTestVectors)368 TEST(ECDSATest, VerifyTestVectors) {
369 FileTestGTest("crypto/fipsmodule/ecdsa/ecdsa_verify_tests.txt",
370 [](FileTest *t) {
371 for (bool custom_group : {false, true}) {
372 SCOPED_TRACE(custom_group);
373 bssl::UniquePtr<EC_GROUP> group = GetCurve(t, "Curve");
374 ASSERT_TRUE(group);
375 if (custom_group) {
376 group = MakeCustomClone(group.get());
377 ASSERT_TRUE(group);
378 }
379 bssl::UniquePtr<BIGNUM> x = GetBIGNUM(t, "X");
380 ASSERT_TRUE(x);
381 bssl::UniquePtr<BIGNUM> y = GetBIGNUM(t, "Y");
382 ASSERT_TRUE(y);
383 bssl::UniquePtr<BIGNUM> r = GetBIGNUM(t, "R");
384 ASSERT_TRUE(r);
385 bssl::UniquePtr<BIGNUM> s = GetBIGNUM(t, "S");
386 ASSERT_TRUE(s);
387 std::vector<uint8_t> digest;
388 ASSERT_TRUE(t->GetBytes(&digest, "Digest"));
389
390 bssl::UniquePtr<EC_KEY> key(EC_KEY_new());
391 ASSERT_TRUE(key);
392 bssl::UniquePtr<EC_POINT> pub_key(EC_POINT_new(group.get()));
393 ASSERT_TRUE(pub_key);
394 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
395 ASSERT_TRUE(sig);
396 ASSERT_TRUE(EC_KEY_set_group(key.get(), group.get()));
397 ASSERT_TRUE(EC_POINT_set_affine_coordinates_GFp(
398 group.get(), pub_key.get(), x.get(), y.get(), nullptr));
399 ASSERT_TRUE(EC_KEY_set_public_key(key.get(), pub_key.get()));
400 ASSERT_TRUE(BN_copy(sig->r, r.get()));
401 ASSERT_TRUE(BN_copy(sig->s, s.get()));
402
403 EXPECT_EQ(
404 t->HasAttribute("Invalid") ? 0 : 1,
405 ECDSA_do_verify(digest.data(), digest.size(), sig.get(), key.get()));
406 }
407 });
408 }
409
TEST(ECDSATest,SignTestVectors)410 TEST(ECDSATest, SignTestVectors) {
411 FileTestGTest("crypto/fipsmodule/ecdsa/ecdsa_sign_tests.txt",
412 [](FileTest *t) {
413 for (bool custom_group : {false, true}) {
414 SCOPED_TRACE(custom_group);
415 bssl::UniquePtr<EC_GROUP> group = GetCurve(t, "Curve");
416 ASSERT_TRUE(group);
417 if (custom_group) {
418 group = MakeCustomClone(group.get());
419 ASSERT_TRUE(group);
420 }
421 bssl::UniquePtr<BIGNUM> priv_key = GetBIGNUM(t, "Private");
422 ASSERT_TRUE(priv_key);
423 bssl::UniquePtr<BIGNUM> x = GetBIGNUM(t, "X");
424 ASSERT_TRUE(x);
425 bssl::UniquePtr<BIGNUM> y = GetBIGNUM(t, "Y");
426 ASSERT_TRUE(y);
427 bssl::UniquePtr<BIGNUM> k = GetBIGNUM(t, "K");
428 ASSERT_TRUE(k);
429 bssl::UniquePtr<BIGNUM> r = GetBIGNUM(t, "R");
430 ASSERT_TRUE(r);
431 bssl::UniquePtr<BIGNUM> s = GetBIGNUM(t, "S");
432 ASSERT_TRUE(s);
433 std::vector<uint8_t> digest;
434 ASSERT_TRUE(t->GetBytes(&digest, "Digest"));
435
436 bssl::UniquePtr<EC_KEY> key(EC_KEY_new());
437 ASSERT_TRUE(key);
438 bssl::UniquePtr<EC_POINT> pub_key(EC_POINT_new(group.get()));
439 ASSERT_TRUE(pub_key);
440 ASSERT_TRUE(EC_KEY_set_group(key.get(), group.get()));
441 ASSERT_TRUE(EC_KEY_set_private_key(key.get(), priv_key.get()));
442 ASSERT_TRUE(EC_POINT_set_affine_coordinates_GFp(
443 group.get(), pub_key.get(), x.get(), y.get(), nullptr));
444 ASSERT_TRUE(EC_KEY_set_public_key(key.get(), pub_key.get()));
445 ASSERT_TRUE(EC_KEY_check_key(key.get()));
446
447 // Set the fixed k for testing purposes.
448 key->fixed_k = k.release();
449 bssl::UniquePtr<ECDSA_SIG> sig(
450 ECDSA_do_sign(digest.data(), digest.size(), key.get()));
451 ASSERT_TRUE(sig);
452
453 EXPECT_EQ(0, BN_cmp(r.get(), sig->r));
454 EXPECT_EQ(0, BN_cmp(s.get(), sig->s));
455 }
456 });
457 }
458