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 <openssl/bn.h>
58 #include <openssl/crypto.h>
59 #include <openssl/ec.h>
60 #include <openssl/err.h>
61 #include <openssl/mem.h>
62 #include <openssl/nid.h>
63 #include <openssl/rand.h>
64
65 enum Api {
66 kEncodedApi,
67 kRawApi,
68 };
69
70 // VerifyECDSASig returns true on success, false on failure.
VerifyECDSASig(Api api,const uint8_t * digest,size_t digest_len,const ECDSA_SIG * ecdsa_sig,EC_KEY * eckey,int expected_result)71 static bool VerifyECDSASig(Api api, const uint8_t *digest,
72 size_t digest_len, const ECDSA_SIG *ecdsa_sig,
73 EC_KEY *eckey, int expected_result) {
74 int actual_result;
75
76 switch (api) {
77 case kEncodedApi: {
78 uint8_t *der;
79 size_t der_len;
80 if (!ECDSA_SIG_to_bytes(&der, &der_len, ecdsa_sig)) {
81 return false;
82 }
83 bssl::UniquePtr<uint8_t> delete_der(der);
84 actual_result = ECDSA_verify(0, digest, digest_len, der, der_len, eckey);
85 break;
86 }
87
88 case kRawApi:
89 actual_result = ECDSA_do_verify(digest, digest_len, ecdsa_sig, eckey);
90 break;
91
92 default:
93 return false;
94 }
95 return expected_result == actual_result;
96 }
97
98 // TestTamperedSig verifies that signature verification fails when a valid
99 // signature is tampered with. |ecdsa_sig| must be a valid signature, which will
100 // be modified. TestTamperedSig returns true on success, false on failure.
TestTamperedSig(FILE * out,Api api,const uint8_t * digest,size_t digest_len,ECDSA_SIG * ecdsa_sig,EC_KEY * eckey,const BIGNUM * order)101 static bool TestTamperedSig(FILE *out, Api api, const uint8_t *digest,
102 size_t digest_len, ECDSA_SIG *ecdsa_sig,
103 EC_KEY *eckey, const BIGNUM *order) {
104 // Modify a single byte of the signature: to ensure we don't
105 // garble the ASN1 structure, we read the raw signature and
106 // modify a byte in one of the bignums directly.
107
108 // Store the two BIGNUMs in raw_buf.
109 size_t r_len = BN_num_bytes(ecdsa_sig->r);
110 size_t s_len = BN_num_bytes(ecdsa_sig->s);
111 size_t bn_len = BN_num_bytes(order);
112 if (r_len > bn_len || s_len > bn_len) {
113 return false;
114 }
115 size_t buf_len = 2 * bn_len;
116 std::vector<uint8_t> raw_buf(buf_len);
117 // Pad the bignums with leading zeroes.
118 if (!BN_bn2bin_padded(raw_buf.data(), bn_len, ecdsa_sig->r) ||
119 !BN_bn2bin_padded(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s)) {
120 return false;
121 }
122
123 // Modify a single byte in the buffer.
124 size_t offset = raw_buf[10] % buf_len;
125 uint8_t dirt = raw_buf[11] ? raw_buf[11] : 1;
126 raw_buf[offset] ^= dirt;
127 // Now read the BIGNUMs back in from raw_buf.
128 if (BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL ||
129 BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s) == NULL ||
130 !VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 0)) {
131 return false;
132 }
133
134 // Sanity check: Undo the modification and verify signature.
135 raw_buf[offset] ^= dirt;
136 if (BN_bin2bn(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL ||
137 BN_bin2bn(raw_buf.data() + bn_len, bn_len, ecdsa_sig->s) == NULL ||
138 !VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 1)) {
139 return false;
140 }
141
142 return true;
143 }
144
TestBuiltin(FILE * out)145 static bool TestBuiltin(FILE *out) {
146 // Fill digest values with some random data.
147 uint8_t digest[20], wrong_digest[20];
148 if (!RAND_bytes(digest, 20) || !RAND_bytes(wrong_digest, 20)) {
149 fprintf(out, "ERROR: unable to get random data\n");
150 return false;
151 }
152
153 static const struct {
154 int nid;
155 const char *name;
156 } kCurves[] = {
157 { NID_secp224r1, "secp224r1" },
158 { NID_X9_62_prime256v1, "secp256r1" },
159 { NID_secp384r1, "secp384r1" },
160 { NID_secp521r1, "secp521r1" },
161 { NID_undef, NULL }
162 };
163
164 // Create and verify ECDSA signatures with every available curve.
165 fputs("\ntesting ECDSA_sign(), ECDSA_verify(), ECDSA_do_sign(), and "
166 "ECDSA_do_verify() with some internal curves:\n", out);
167
168 for (size_t n = 0; kCurves[n].nid != NID_undef; n++) {
169 fprintf(out, "%s: ", kCurves[n].name);
170
171 int nid = kCurves[n].nid;
172 bssl::UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid));
173 if (!group) {
174 fprintf(out, " failed\n");
175 return false;
176 }
177 const BIGNUM *order = EC_GROUP_get0_order(group.get());
178 if (BN_num_bits(order) < 160) {
179 // Too small to test.
180 fprintf(out, " skipped\n");
181 continue;
182 }
183
184 // Create a new ECDSA key.
185 bssl::UniquePtr<EC_KEY> eckey(EC_KEY_new());
186 if (!eckey || !EC_KEY_set_group(eckey.get(), group.get()) ||
187 !EC_KEY_generate_key(eckey.get())) {
188 fprintf(out, " failed\n");
189 return false;
190 }
191 // Create a second key.
192 bssl::UniquePtr<EC_KEY> wrong_eckey(EC_KEY_new());
193 if (!wrong_eckey || !EC_KEY_set_group(wrong_eckey.get(), group.get()) ||
194 !EC_KEY_generate_key(wrong_eckey.get())) {
195 fprintf(out, " failed\n");
196 return false;
197 }
198
199 fprintf(out, ".");
200 fflush(out);
201
202 // Check the key.
203 if (!EC_KEY_check_key(eckey.get())) {
204 fprintf(out, " failed\n");
205 return false;
206 }
207 fprintf(out, ".");
208 fflush(out);
209
210 // Test ASN.1-encoded signatures.
211 // Create a signature.
212 unsigned sig_len = ECDSA_size(eckey.get());
213 std::vector<uint8_t> signature(sig_len);
214 if (!ECDSA_sign(0, digest, 20, signature.data(), &sig_len, eckey.get())) {
215 fprintf(out, " failed\n");
216 return false;
217 }
218 signature.resize(sig_len);
219 fprintf(out, ".");
220 fflush(out);
221 // Verify the signature.
222 if (!ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
223 eckey.get())) {
224 fprintf(out, " failed\n");
225 return false;
226 }
227 fprintf(out, ".");
228 fflush(out);
229 // Verify the signature with the wrong key.
230 if (ECDSA_verify(0, digest, 20, signature.data(), signature.size(),
231 wrong_eckey.get())) {
232 fprintf(out, " failed\n");
233 return false;
234 }
235 fprintf(out, ".");
236 fflush(out);
237 // Verify the signature using the wrong digest.
238 if (ECDSA_verify(0, wrong_digest, 20, signature.data(), signature.size(),
239 eckey.get())) {
240 fprintf(out, " failed\n");
241 return false;
242 }
243 fprintf(out, ".");
244 fflush(out);
245 // Verify a truncated signature.
246 if (ECDSA_verify(0, digest, 20, signature.data(), signature.size() - 1,
247 eckey.get())) {
248 fprintf(out, " failed\n");
249 return false;
250 }
251 fprintf(out, ".");
252 fflush(out);
253 // Verify a tampered signature.
254 bssl::UniquePtr<ECDSA_SIG> ecdsa_sig(ECDSA_SIG_from_bytes(
255 signature.data(), signature.size()));
256 if (!ecdsa_sig ||
257 !TestTamperedSig(out, kEncodedApi, digest, 20, ecdsa_sig.get(),
258 eckey.get(), order)) {
259 fprintf(out, " failed\n");
260 return false;
261 }
262 fprintf(out, ".");
263 fflush(out);
264
265 // Test ECDSA_SIG signing and verification.
266 // Create a signature.
267 ecdsa_sig.reset(ECDSA_do_sign(digest, 20, eckey.get()));
268 if (!ecdsa_sig) {
269 fprintf(out, " failed\n");
270 return false;
271 }
272 fprintf(out, ".");
273 fflush(out);
274 // Verify the signature using the correct key.
275 if (!ECDSA_do_verify(digest, 20, ecdsa_sig.get(), eckey.get())) {
276 fprintf(out, " failed\n");
277 return false;
278 }
279 fprintf(out, ".");
280 fflush(out);
281 // Verify the signature with the wrong key.
282 if (ECDSA_do_verify(digest, 20, ecdsa_sig.get(), wrong_eckey.get())) {
283 fprintf(out, " failed\n");
284 return false;
285 }
286 fprintf(out, ".");
287 fflush(out);
288 // Verify the signature using the wrong digest.
289 if (ECDSA_do_verify(wrong_digest, 20, ecdsa_sig.get(), eckey.get())) {
290 fprintf(out, " failed\n");
291 return false;
292 }
293 fprintf(out, ".");
294 fflush(out);
295 // Verify a tampered signature.
296 if (!TestTamperedSig(out, kRawApi, digest, 20, ecdsa_sig.get(), eckey.get(),
297 order)) {
298 fprintf(out, " failed\n");
299 return false;
300 }
301 fprintf(out, ".");
302 fflush(out);
303
304 fprintf(out, " ok\n");
305 // Clear bogus errors.
306 ERR_clear_error();
307 }
308
309 return true;
310 }
311
TestECDSA_SIG_max_len(size_t order_len)312 static bool TestECDSA_SIG_max_len(size_t order_len) {
313 /* Create the largest possible |ECDSA_SIG| of the given constraints. */
314 bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
315 if (!sig) {
316 return false;
317 }
318 std::vector<uint8_t> bytes(order_len, 0xff);
319 if (!BN_bin2bn(bytes.data(), bytes.size(), sig->r) ||
320 !BN_bin2bn(bytes.data(), bytes.size(), sig->s)) {
321 return false;
322 }
323 /* Serialize it. */
324 uint8_t *der;
325 size_t der_len;
326 if (!ECDSA_SIG_to_bytes(&der, &der_len, sig.get())) {
327 return false;
328 }
329 bssl::UniquePtr<uint8_t> delete_der(der);
330
331 size_t max_len = ECDSA_SIG_max_len(order_len);
332 if (max_len != der_len) {
333 fprintf(stderr, "ECDSA_SIG_max_len(%u) returned %u, wanted %u\n",
334 static_cast<unsigned>(order_len), static_cast<unsigned>(max_len),
335 static_cast<unsigned>(der_len));
336 return false;
337 }
338 return true;
339 }
340
BitsToBytes(size_t bits)341 static size_t BitsToBytes(size_t bits) {
342 return (bits / 8) + (7 + (bits % 8)) / 8;
343 }
344
main(void)345 int main(void) {
346 CRYPTO_library_init();
347
348 if (!TestBuiltin(stdout) ||
349 !TestECDSA_SIG_max_len(BitsToBytes(224)) ||
350 !TestECDSA_SIG_max_len(BitsToBytes(256)) ||
351 !TestECDSA_SIG_max_len(BitsToBytes(384)) ||
352 !TestECDSA_SIG_max_len(BitsToBytes(521)) ||
353 !TestECDSA_SIG_max_len(BitsToBytes(10000))) {
354 printf("\nECDSA test failed\n");
355 ERR_print_errors_fp(stdout);
356 return 1;
357 }
358
359 printf("\nPASS\n");
360 return 0;
361 }
362