1 /*
2 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /*
11 * RSA low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdio.h>
17 #include "internal/cryptlib.h"
18 #include <openssl/bn.h>
19 #include <openssl/rsa.h>
20 #include <openssl/objects.h>
21 #ifndef FIPS_MODULE
22 # ifndef OPENSSL_NO_MD2
23 # include <openssl/md2.h> /* uses MD2_DIGEST_LENGTH */
24 # endif
25 # ifndef OPENSSL_NO_MD4
26 # include <openssl/md4.h> /* uses MD4_DIGEST_LENGTH */
27 # endif
28 # ifndef OPENSSL_NO_MD5
29 # include <openssl/md5.h> /* uses MD5_DIGEST_LENGTH */
30 # endif
31 # ifndef OPENSSL_NO_MDC2
32 # include <openssl/mdc2.h> /* uses MDC2_DIGEST_LENGTH */
33 # endif
34 # ifndef OPENSSL_NO_RMD160
35 # include <openssl/ripemd.h> /* uses RIPEMD160_DIGEST_LENGTH */
36 # endif
37 #endif
38 #include <openssl/sha.h> /* uses SHA???_DIGEST_LENGTH */
39 #include "crypto/rsa.h"
40 #include "rsa_local.h"
41
42 /*
43 * The general purpose ASN1 code is not available inside the FIPS provider.
44 * To remove the dependency RSASSA-PKCS1-v1_5 DigestInfo encodings can be
45 * treated as a special case by pregenerating the required ASN1 encoding.
46 * This encoding will also be shared by the default provider.
47 *
48 * The EMSA-PKCS1-v1_5 encoding method includes an ASN.1 value of type
49 * DigestInfo, where the type DigestInfo has the syntax
50 *
51 * DigestInfo ::= SEQUENCE {
52 * digestAlgorithm DigestAlgorithm,
53 * digest OCTET STRING
54 * }
55 *
56 * DigestAlgorithm ::= AlgorithmIdentifier {
57 * {PKCS1-v1-5DigestAlgorithms}
58 * }
59 *
60 * The AlgorithmIdentifier is a sequence containing the digest OID and
61 * parameters (a value of type NULL).
62 *
63 * The ENCODE_DIGESTINFO_SHA() and ENCODE_DIGESTINFO_MD() macros define an
64 * initialized array containing the DER encoded DigestInfo for the specified
65 * SHA or MD digest. The content of the OCTET STRING is not included.
66 * |name| is the digest name.
67 * |n| is last byte in the encoded OID for the digest.
68 * |sz| is the digest length in bytes. It must not be greater than 110.
69 */
70
71 #define ASN1_SEQUENCE 0x30
72 #define ASN1_OCTET_STRING 0x04
73 #define ASN1_NULL 0x05
74 #define ASN1_OID 0x06
75
76 /* SHA OIDs are of the form: (2 16 840 1 101 3 4 2 |n|) */
77 #define ENCODE_DIGESTINFO_SHA(name, n, sz) \
78 static const unsigned char digestinfo_##name##_der[] = { \
79 ASN1_SEQUENCE, 0x11 + sz, \
80 ASN1_SEQUENCE, 0x0d, \
81 ASN1_OID, 0x09, 2 * 40 + 16, 0x86, 0x48, 1, 101, 3, 4, 2, n, \
82 ASN1_NULL, 0x00, \
83 ASN1_OCTET_STRING, sz \
84 };
85
86 /* MD2, MD4 and MD5 OIDs are of the form: (1 2 840 113549 2 |n|) */
87 #define ENCODE_DIGESTINFO_MD(name, n, sz) \
88 static const unsigned char digestinfo_##name##_der[] = { \
89 ASN1_SEQUENCE, 0x10 + sz, \
90 ASN1_SEQUENCE, 0x0c, \
91 ASN1_OID, 0x08, 1 * 40 + 2, 0x86, 0x48, 0x86, 0xf7, 0x0d, 2, n, \
92 ASN1_NULL, 0x00, \
93 ASN1_OCTET_STRING, sz \
94 };
95
96 #ifndef FIPS_MODULE
97 # ifndef OPENSSL_NO_MD2
98 ENCODE_DIGESTINFO_MD(md2, 0x02, MD2_DIGEST_LENGTH)
99 # endif
100 # ifndef OPENSSL_NO_MD4
101 ENCODE_DIGESTINFO_MD(md4, 0x03, MD4_DIGEST_LENGTH)
102 # endif
103 # ifndef OPENSSL_NO_MD5
104 ENCODE_DIGESTINFO_MD(md5, 0x05, MD5_DIGEST_LENGTH)
105 # endif
106 # ifndef OPENSSL_NO_MDC2
107 /* MDC-2 (2 5 8 3 101) */
108 static const unsigned char digestinfo_mdc2_der[] = {
109 ASN1_SEQUENCE, 0x0c + MDC2_DIGEST_LENGTH,
110 ASN1_SEQUENCE, 0x08,
111 ASN1_OID, 0x04, 2 * 40 + 5, 8, 3, 101,
112 ASN1_NULL, 0x00,
113 ASN1_OCTET_STRING, MDC2_DIGEST_LENGTH
114 };
115 # endif
116 # ifndef OPENSSL_NO_RMD160
117 /* RIPEMD160 (1 3 36 3 2 1) */
118 static const unsigned char digestinfo_ripemd160_der[] = {
119 ASN1_SEQUENCE, 0x0d + RIPEMD160_DIGEST_LENGTH,
120 ASN1_SEQUENCE, 0x09,
121 ASN1_OID, 0x05, 1 * 40 + 3, 36, 3, 2, 1,
122 ASN1_NULL, 0x00,
123 ASN1_OCTET_STRING, RIPEMD160_DIGEST_LENGTH
124 };
125 # endif
126 #endif /* FIPS_MODULE */
127
128 /* SHA-1 (1 3 14 3 2 26) */
129 static const unsigned char digestinfo_sha1_der[] = {
130 ASN1_SEQUENCE, 0x0d + SHA_DIGEST_LENGTH,
131 ASN1_SEQUENCE, 0x09,
132 ASN1_OID, 0x05, 1 * 40 + 3, 14, 3, 2, 26,
133 ASN1_NULL, 0x00,
134 ASN1_OCTET_STRING, SHA_DIGEST_LENGTH
135 };
136
137 ENCODE_DIGESTINFO_SHA(sha256, 0x01, SHA256_DIGEST_LENGTH)
138 ENCODE_DIGESTINFO_SHA(sha384, 0x02, SHA384_DIGEST_LENGTH)
139 ENCODE_DIGESTINFO_SHA(sha512, 0x03, SHA512_DIGEST_LENGTH)
140 ENCODE_DIGESTINFO_SHA(sha224, 0x04, SHA224_DIGEST_LENGTH)
141 ENCODE_DIGESTINFO_SHA(sha512_224, 0x05, SHA224_DIGEST_LENGTH)
142 ENCODE_DIGESTINFO_SHA(sha512_256, 0x06, SHA256_DIGEST_LENGTH)
143 ENCODE_DIGESTINFO_SHA(sha3_224, 0x07, SHA224_DIGEST_LENGTH)
144 ENCODE_DIGESTINFO_SHA(sha3_256, 0x08, SHA256_DIGEST_LENGTH)
145 ENCODE_DIGESTINFO_SHA(sha3_384, 0x09, SHA384_DIGEST_LENGTH)
146 ENCODE_DIGESTINFO_SHA(sha3_512, 0x0a, SHA512_DIGEST_LENGTH)
147
148 #define MD_CASE(name) \
149 case NID_##name: \
150 *len = sizeof(digestinfo_##name##_der); \
151 return digestinfo_##name##_der;
152
ossl_rsa_digestinfo_encoding(int md_nid,size_t * len)153 const unsigned char *ossl_rsa_digestinfo_encoding(int md_nid, size_t *len)
154 {
155 switch (md_nid) {
156 #ifndef FIPS_MODULE
157 # ifndef OPENSSL_NO_MDC2
158 MD_CASE(mdc2)
159 # endif
160 # ifndef OPENSSL_NO_MD2
161 MD_CASE(md2)
162 # endif
163 # ifndef OPENSSL_NO_MD4
164 MD_CASE(md4)
165 # endif
166 # ifndef OPENSSL_NO_MD5
167 MD_CASE(md5)
168 # endif
169 # ifndef OPENSSL_NO_RMD160
170 MD_CASE(ripemd160)
171 # endif
172 #endif /* FIPS_MODULE */
173 MD_CASE(sha1)
174 MD_CASE(sha224)
175 MD_CASE(sha256)
176 MD_CASE(sha384)
177 MD_CASE(sha512)
178 MD_CASE(sha512_224)
179 MD_CASE(sha512_256)
180 MD_CASE(sha3_224)
181 MD_CASE(sha3_256)
182 MD_CASE(sha3_384)
183 MD_CASE(sha3_512)
184 default:
185 return NULL;
186 }
187 }
188
189 #define MD_NID_CASE(name, sz) \
190 case NID_##name: \
191 return sz;
192
digest_sz_from_nid(int nid)193 static int digest_sz_from_nid(int nid)
194 {
195 switch (nid) {
196 #ifndef FIPS_MODULE
197 # ifndef OPENSSL_NO_MDC2
198 MD_NID_CASE(mdc2, MDC2_DIGEST_LENGTH)
199 # endif
200 # ifndef OPENSSL_NO_MD2
201 MD_NID_CASE(md2, MD2_DIGEST_LENGTH)
202 # endif
203 # ifndef OPENSSL_NO_MD4
204 MD_NID_CASE(md4, MD4_DIGEST_LENGTH)
205 # endif
206 # ifndef OPENSSL_NO_MD5
207 MD_NID_CASE(md5, MD5_DIGEST_LENGTH)
208 # endif
209 # ifndef OPENSSL_NO_RMD160
210 MD_NID_CASE(ripemd160, RIPEMD160_DIGEST_LENGTH)
211 # endif
212 #endif /* FIPS_MODULE */
213 MD_NID_CASE(sha1, SHA_DIGEST_LENGTH)
214 MD_NID_CASE(sha224, SHA224_DIGEST_LENGTH)
215 MD_NID_CASE(sha256, SHA256_DIGEST_LENGTH)
216 MD_NID_CASE(sha384, SHA384_DIGEST_LENGTH)
217 MD_NID_CASE(sha512, SHA512_DIGEST_LENGTH)
218 MD_NID_CASE(sha512_224, SHA224_DIGEST_LENGTH)
219 MD_NID_CASE(sha512_256, SHA256_DIGEST_LENGTH)
220 MD_NID_CASE(sha3_224, SHA224_DIGEST_LENGTH)
221 MD_NID_CASE(sha3_256, SHA256_DIGEST_LENGTH)
222 MD_NID_CASE(sha3_384, SHA384_DIGEST_LENGTH)
223 MD_NID_CASE(sha3_512, SHA512_DIGEST_LENGTH)
224 default:
225 return 0;
226 }
227 }
228
229
230 /* Size of an SSL signature: MD5+SHA1 */
231 #define SSL_SIG_LENGTH 36
232
233 /*
234 * Encodes a DigestInfo prefix of hash |type| and digest |m|, as
235 * described in EMSA-PKCS1-v1_5-ENCODE, RFC 3447 section 9.2 step 2. This
236 * encodes the DigestInfo (T and tLen) but does not add the padding.
237 *
238 * On success, it returns one and sets |*out| to a newly allocated buffer
239 * containing the result and |*out_len| to its length. The caller must free
240 * |*out| with OPENSSL_free(). Otherwise, it returns zero.
241 */
encode_pkcs1(unsigned char ** out,size_t * out_len,int type,const unsigned char * m,size_t m_len)242 static int encode_pkcs1(unsigned char **out, size_t *out_len, int type,
243 const unsigned char *m, size_t m_len)
244 {
245 size_t di_prefix_len, dig_info_len;
246 const unsigned char *di_prefix;
247 unsigned char *dig_info;
248
249 if (type == NID_undef) {
250 ERR_raise(ERR_LIB_RSA, RSA_R_UNKNOWN_ALGORITHM_TYPE);
251 return 0;
252 }
253 di_prefix = ossl_rsa_digestinfo_encoding(type, &di_prefix_len);
254 if (di_prefix == NULL) {
255 ERR_raise(ERR_LIB_RSA,
256 RSA_R_THE_ASN1_OBJECT_IDENTIFIER_IS_NOT_KNOWN_FOR_THIS_MD);
257 return 0;
258 }
259 dig_info_len = di_prefix_len + m_len;
260 dig_info = OPENSSL_malloc(dig_info_len);
261 if (dig_info == NULL) {
262 ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
263 return 0;
264 }
265 memcpy(dig_info, di_prefix, di_prefix_len);
266 memcpy(dig_info + di_prefix_len, m, m_len);
267
268 *out = dig_info;
269 *out_len = dig_info_len;
270 return 1;
271 }
272
RSA_sign(int type,const unsigned char * m,unsigned int m_len,unsigned char * sigret,unsigned int * siglen,RSA * rsa)273 int RSA_sign(int type, const unsigned char *m, unsigned int m_len,
274 unsigned char *sigret, unsigned int *siglen, RSA *rsa)
275 {
276 int encrypt_len, ret = 0;
277 size_t encoded_len = 0;
278 unsigned char *tmps = NULL;
279 const unsigned char *encoded = NULL;
280
281 #ifndef FIPS_MODULE
282 if (rsa->meth->rsa_sign != NULL)
283 return rsa->meth->rsa_sign(type, m, m_len, sigret, siglen, rsa);
284 #endif /* FIPS_MODULE */
285
286 /* Compute the encoded digest. */
287 if (type == NID_md5_sha1) {
288 /*
289 * NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
290 * earlier. It has no DigestInfo wrapper but otherwise is
291 * RSASSA-PKCS1-v1_5.
292 */
293 if (m_len != SSL_SIG_LENGTH) {
294 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MESSAGE_LENGTH);
295 return 0;
296 }
297 encoded_len = SSL_SIG_LENGTH;
298 encoded = m;
299 } else {
300 if (!encode_pkcs1(&tmps, &encoded_len, type, m, m_len))
301 goto err;
302 encoded = tmps;
303 }
304
305 if (encoded_len + RSA_PKCS1_PADDING_SIZE > (size_t)RSA_size(rsa)) {
306 ERR_raise(ERR_LIB_RSA, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY);
307 goto err;
308 }
309 encrypt_len = RSA_private_encrypt((int)encoded_len, encoded, sigret, rsa,
310 RSA_PKCS1_PADDING);
311 if (encrypt_len <= 0)
312 goto err;
313
314 *siglen = encrypt_len;
315 ret = 1;
316
317 err:
318 OPENSSL_clear_free(tmps, encoded_len);
319 return ret;
320 }
321
322 /*
323 * Verify an RSA signature in |sigbuf| using |rsa|.
324 * |type| is the NID of the digest algorithm to use.
325 * If |rm| is NULL, it verifies the signature for digest |m|, otherwise
326 * it recovers the digest from the signature, writing the digest to |rm| and
327 * the length to |*prm_len|.
328 *
329 * It returns one on successful verification or zero otherwise.
330 */
ossl_rsa_verify(int type,const unsigned char * m,unsigned int m_len,unsigned char * rm,size_t * prm_len,const unsigned char * sigbuf,size_t siglen,RSA * rsa)331 int ossl_rsa_verify(int type, const unsigned char *m, unsigned int m_len,
332 unsigned char *rm, size_t *prm_len,
333 const unsigned char *sigbuf, size_t siglen, RSA *rsa)
334 {
335 int len, ret = 0;
336 size_t decrypt_len, encoded_len = 0;
337 unsigned char *decrypt_buf = NULL, *encoded = NULL;
338
339 if (siglen != (size_t)RSA_size(rsa)) {
340 ERR_raise(ERR_LIB_RSA, RSA_R_WRONG_SIGNATURE_LENGTH);
341 return 0;
342 }
343
344 /* Recover the encoded digest. */
345 decrypt_buf = OPENSSL_malloc(siglen);
346 if (decrypt_buf == NULL) {
347 ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
348 goto err;
349 }
350
351 len = RSA_public_decrypt((int)siglen, sigbuf, decrypt_buf, rsa,
352 RSA_PKCS1_PADDING);
353 if (len <= 0)
354 goto err;
355 decrypt_len = len;
356
357 #ifndef FIPS_MODULE
358 if (type == NID_md5_sha1) {
359 /*
360 * NID_md5_sha1 corresponds to the MD5/SHA1 combination in TLS 1.1 and
361 * earlier. It has no DigestInfo wrapper but otherwise is
362 * RSASSA-PKCS1-v1_5.
363 */
364 if (decrypt_len != SSL_SIG_LENGTH) {
365 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
366 goto err;
367 }
368
369 if (rm != NULL) {
370 memcpy(rm, decrypt_buf, SSL_SIG_LENGTH);
371 *prm_len = SSL_SIG_LENGTH;
372 } else {
373 if (m_len != SSL_SIG_LENGTH) {
374 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MESSAGE_LENGTH);
375 goto err;
376 }
377
378 if (memcmp(decrypt_buf, m, SSL_SIG_LENGTH) != 0) {
379 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
380 goto err;
381 }
382 }
383 } else if (type == NID_mdc2 && decrypt_len == 2 + 16
384 && decrypt_buf[0] == 0x04 && decrypt_buf[1] == 0x10) {
385 /*
386 * Oddball MDC2 case: signature can be OCTET STRING. check for correct
387 * tag and length octets.
388 */
389 if (rm != NULL) {
390 memcpy(rm, decrypt_buf + 2, 16);
391 *prm_len = 16;
392 } else {
393 if (m_len != 16) {
394 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MESSAGE_LENGTH);
395 goto err;
396 }
397
398 if (memcmp(m, decrypt_buf + 2, 16) != 0) {
399 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
400 goto err;
401 }
402 }
403 } else
404 #endif /* FIPS_MODULE */
405 {
406 /*
407 * If recovering the digest, extract a digest-sized output from the end
408 * of |decrypt_buf| for |encode_pkcs1|, then compare the decryption
409 * output as in a standard verification.
410 */
411 if (rm != NULL) {
412 len = digest_sz_from_nid(type);
413
414 if (len <= 0)
415 goto err;
416 m_len = (unsigned int)len;
417 if (m_len > decrypt_len) {
418 ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_DIGEST_LENGTH);
419 goto err;
420 }
421 m = decrypt_buf + decrypt_len - m_len;
422 }
423
424 /* Construct the encoded digest and ensure it matches. */
425 if (!encode_pkcs1(&encoded, &encoded_len, type, m, m_len))
426 goto err;
427
428 if (encoded_len != decrypt_len
429 || memcmp(encoded, decrypt_buf, encoded_len) != 0) {
430 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_SIGNATURE);
431 goto err;
432 }
433
434 /* Output the recovered digest. */
435 if (rm != NULL) {
436 memcpy(rm, m, m_len);
437 *prm_len = m_len;
438 }
439 }
440
441 ret = 1;
442
443 err:
444 OPENSSL_clear_free(encoded, encoded_len);
445 OPENSSL_clear_free(decrypt_buf, siglen);
446 return ret;
447 }
448
RSA_verify(int type,const unsigned char * m,unsigned int m_len,const unsigned char * sigbuf,unsigned int siglen,RSA * rsa)449 int RSA_verify(int type, const unsigned char *m, unsigned int m_len,
450 const unsigned char *sigbuf, unsigned int siglen, RSA *rsa)
451 {
452
453 if (rsa->meth->rsa_verify != NULL)
454 return rsa->meth->rsa_verify(type, m, m_len, sigbuf, siglen, rsa);
455
456 return ossl_rsa_verify(type, m, m_len, NULL, NULL, sigbuf, siglen, rsa);
457 }
458
