1 /* rsa_pss.c */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project 2005.
4 */
5 /* ====================================================================
6 * Copyright (c) 2005 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * licensing@OpenSSL.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include <openssl/bn.h>
62 #include <openssl/rsa.h>
63 #include <openssl/evp.h>
64 #include <openssl/rand.h>
65 #include <openssl/sha.h>
66
67 static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
68
69 #if defined(_MSC_VER) && defined(_ARM_)
70 #pragma optimize("g", off)
71 #endif
72
73 int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
74 const EVP_MD *Hash, const unsigned char *EM, int sLen)
75 {
76 return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
77 }
78
79 int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
80 const EVP_MD *Hash, const EVP_MD *mgf1Hash,
81 const unsigned char *EM, int sLen)
82 {
83 int i;
84 int ret = 0;
85 int hLen, maskedDBLen, MSBits, emLen;
86 const unsigned char *H;
87 unsigned char *DB = NULL;
88 EVP_MD_CTX ctx;
89 unsigned char H_[EVP_MAX_MD_SIZE];
90 EVP_MD_CTX_init(&ctx);
91
92 if (mgf1Hash == NULL)
93 mgf1Hash = Hash;
94
95 hLen = EVP_MD_size(Hash);
96 if (hLen < 0)
97 goto err;
98 /*
99 * Negative sLen has special meanings:
100 * -1 sLen == hLen
101 * -2 salt length is autorecovered from signature
102 * -N reserved
103 */
104 if (sLen == -1) sLen = hLen;
105 else if (sLen == -2) sLen = -2;
106 else if (sLen < -2)
107 {
108 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
109 goto err;
110 }
111
112 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
113 emLen = RSA_size(rsa);
114 if (EM[0] & (0xFF << MSBits))
115 {
116 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID);
117 goto err;
118 }
119 if (MSBits == 0)
120 {
121 EM++;
122 emLen--;
123 }
124 if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
125 {
126 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
127 goto err;
128 }
129 if (EM[emLen - 1] != 0xbc)
130 {
131 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID);
132 goto err;
133 }
134 maskedDBLen = emLen - hLen - 1;
135 H = EM + maskedDBLen;
136 DB = OPENSSL_malloc(maskedDBLen);
137 if (!DB)
138 {
139 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE);
140 goto err;
141 }
142 if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
143 goto err;
144 for (i = 0; i < maskedDBLen; i++)
145 DB[i] ^= EM[i];
146 if (MSBits)
147 DB[0] &= 0xFF >> (8 - MSBits);
148 for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
149 if (DB[i++] != 0x1)
150 {
151 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED);
152 goto err;
153 }
154 if (sLen >= 0 && (maskedDBLen - i) != sLen)
155 {
156 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
157 goto err;
158 }
159 if (!EVP_DigestInit_ex(&ctx, Hash, NULL)
160 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes)
161 || !EVP_DigestUpdate(&ctx, mHash, hLen))
162 goto err;
163 if (maskedDBLen - i)
164 {
165 if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i))
166 goto err;
167 }
168 if (!EVP_DigestFinal_ex(&ctx, H_, NULL))
169 goto err;
170 if (memcmp(H_, H, hLen))
171 {
172 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE);
173 ret = 0;
174 }
175 else
176 ret = 1;
177
178 err:
179 if (DB)
180 OPENSSL_free(DB);
181 EVP_MD_CTX_cleanup(&ctx);
182
183 return ret;
184
185 }
186
187 int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
188 const unsigned char *mHash,
189 const EVP_MD *Hash, int sLen)
190 {
191 return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
192 }
193
194 int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
195 const unsigned char *mHash,
196 const EVP_MD *Hash, const EVP_MD *mgf1Hash, int sLen)
197 {
198 int i;
199 int ret = 0;
200 int hLen, maskedDBLen, MSBits, emLen;
201 unsigned char *H, *salt = NULL, *p;
202 EVP_MD_CTX ctx;
203
204 if (mgf1Hash == NULL)
205 mgf1Hash = Hash;
206
207 hLen = EVP_MD_size(Hash);
208 if (hLen < 0)
209 goto err;
210 /*
211 * Negative sLen has special meanings:
212 * -1 sLen == hLen
213 * -2 salt length is maximized
214 * -N reserved
215 */
216 if (sLen == -1) sLen = hLen;
217 else if (sLen == -2) sLen = -2;
218 else if (sLen < -2)
219 {
220 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
221 goto err;
222 }
223
224 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
225 emLen = RSA_size(rsa);
226 if (MSBits == 0)
227 {
228 *EM++ = 0;
229 emLen--;
230 }
231 if (sLen == -2)
232 {
233 sLen = emLen - hLen - 2;
234 }
235 else if (emLen < (hLen + sLen + 2))
236 {
237 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
238 goto err;
239 }
240 if (sLen > 0)
241 {
242 salt = OPENSSL_malloc(sLen);
243 if (!salt)
244 {
245 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,ERR_R_MALLOC_FAILURE);
246 goto err;
247 }
248 if (RAND_bytes(salt, sLen) <= 0)
249 goto err;
250 }
251 maskedDBLen = emLen - hLen - 1;
252 H = EM + maskedDBLen;
253 EVP_MD_CTX_init(&ctx);
254 if (!EVP_DigestInit_ex(&ctx, Hash, NULL)
255 || !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes)
256 || !EVP_DigestUpdate(&ctx, mHash, hLen))
257 goto err;
258 if (sLen && !EVP_DigestUpdate(&ctx, salt, sLen))
259 goto err;
260 if (!EVP_DigestFinal_ex(&ctx, H, NULL))
261 goto err;
262 EVP_MD_CTX_cleanup(&ctx);
263
264 /* Generate dbMask in place then perform XOR on it */
265 if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
266 goto err;
267
268 p = EM;
269
270 /* Initial PS XORs with all zeroes which is a NOP so just update
271 * pointer. Note from a test above this value is guaranteed to
272 * be non-negative.
273 */
274 p += emLen - sLen - hLen - 2;
275 *p++ ^= 0x1;
276 if (sLen > 0)
277 {
278 for (i = 0; i < sLen; i++)
279 *p++ ^= salt[i];
280 }
281 if (MSBits)
282 EM[0] &= 0xFF >> (8 - MSBits);
283
284 /* H is already in place so just set final 0xbc */
285
286 EM[emLen - 1] = 0xbc;
287
288 ret = 1;
289
290 err:
291 if (salt)
292 OPENSSL_free(salt);
293
294 return ret;
295
296 }
297
298 #if defined(_MSC_VER)
299 #pragma optimize("",on)
300 #endif