1/*
2 * Copyright 2005-2018 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#include <stdio.h>
11#include "internal/cryptlib.h"
12#include <openssl/bn.h>
13#include <openssl/rsa.h>
14#include <openssl/evp.h>
15#include <openssl/rand.h>
16#include <openssl/sha.h>
17#include "rsa_local.h"
18
19static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
20
21#if defined(_MSC_VER) && defined(_ARM_)
22# pragma optimize("g", off)
23#endif
24
25int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
26 const EVP_MD *Hash, const unsigned char *EM,
27 int sLen)
28{
29 return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
30}
31
32int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
33 const EVP_MD *Hash, const EVP_MD *mgf1Hash,
34 const unsigned char *EM, int sLen)
35{
36 int i;
37 int ret = 0;
38 int hLen, maskedDBLen, MSBits, emLen;
39 const unsigned char *H;
40 unsigned char *DB = NULL;
41 EVP_MD_CTX *ctx = EVP_MD_CTX_new();
42 unsigned char H_[EVP_MAX_MD_SIZE];
43
44 if (ctx == NULL)
45 goto err;
46
47 if (mgf1Hash == NULL)
48 mgf1Hash = Hash;
49
50 hLen = EVP_MD_size(Hash);
51 if (hLen < 0)
52 goto err;
53 /*-
54 * Negative sLen has special meanings:
55 * -1 sLen == hLen
56 * -2 salt length is autorecovered from signature
57 * -3 salt length is maximized
58 * -N reserved
59 */
60 if (sLen == RSA_PSS_SALTLEN_DIGEST) {
61 sLen = hLen;
62 } else if (sLen < RSA_PSS_SALTLEN_MAX) {
63 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
64 goto err;
65 }
66
67 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
68 emLen = RSA_size(rsa);
69 if (EM[0] & (0xFF << MSBits)) {
70 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID);
71 goto err;
72 }
73 if (MSBits == 0) {
74 EM++;
75 emLen--;
76 }
77 if (emLen < hLen + 2) {
78 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
79 goto err;
80 }
81 if (sLen == RSA_PSS_SALTLEN_MAX) {
82 sLen = emLen - hLen - 2;
83 } else if (sLen > emLen - hLen - 2) { /* sLen can be small negative */
84 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
85 goto err;
86 }
87 if (EM[emLen - 1] != 0xbc) {
88 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID);
89 goto err;
90 }
91 maskedDBLen = emLen - hLen - 1;
92 H = EM + maskedDBLen;
93 DB = OPENSSL_malloc(maskedDBLen);
94 if (DB == NULL) {
95 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE);
96 goto err;
97 }
98 if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
99 goto err;
100 for (i = 0; i < maskedDBLen; i++)
101 DB[i] ^= EM[i];
102 if (MSBits)
103 DB[0] &= 0xFF >> (8 - MSBits);
104 for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ;
105 if (DB[i++] != 0x1) {
106 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED);
107 goto err;
108 }
109 if (sLen != RSA_PSS_SALTLEN_AUTO && (maskedDBLen - i) != sLen) {
110 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
111 goto err;
112 }
113 if (!EVP_DigestInit_ex(ctx, Hash, NULL)
114 || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
115 || !EVP_DigestUpdate(ctx, mHash, hLen))
116 goto err;
117 if (maskedDBLen - i) {
118 if (!EVP_DigestUpdate(ctx, DB + i, maskedDBLen - i))
119 goto err;
120 }
121 if (!EVP_DigestFinal_ex(ctx, H_, NULL))
122 goto err;
123 if (memcmp(H_, H, hLen)) {
124 RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE);
125 ret = 0;
126 } else {
127 ret = 1;
128 }
129
130 err:
131 OPENSSL_free(DB);
132 EVP_MD_CTX_free(ctx);
133
134 return ret;
135
136}
137
138int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
139 const unsigned char *mHash,
140 const EVP_MD *Hash, int sLen)
141{
142 return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
143}
144
145int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
146 const unsigned char *mHash,
147 const EVP_MD *Hash, const EVP_MD *mgf1Hash,
148 int sLen)
149{
150 int i;
151 int ret = 0;
152 int hLen, maskedDBLen, MSBits, emLen;
153 unsigned char *H, *salt = NULL, *p;
154 EVP_MD_CTX *ctx = NULL;
155
156 if (mgf1Hash == NULL)
157 mgf1Hash = Hash;
158
159 hLen = EVP_MD_size(Hash);
160 if (hLen < 0)
161 goto err;
162 /*-
163 * Negative sLen has special meanings:
164 * -1 sLen == hLen
165 * -2 salt length is maximized
166 * -3 same as above (on signing)
167 * -N reserved
168 */
169 if (sLen == RSA_PSS_SALTLEN_DIGEST) {
170 sLen = hLen;
171 } else if (sLen == RSA_PSS_SALTLEN_MAX_SIGN) {
172 sLen = RSA_PSS_SALTLEN_MAX;
173 } else if (sLen < RSA_PSS_SALTLEN_MAX) {
174 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
175 goto err;
176 }
177
178 MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
179 emLen = RSA_size(rsa);
180 if (MSBits == 0) {
181 *EM++ = 0;
182 emLen--;
183 }
184 if (emLen < hLen + 2) {
185 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
186 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
187 goto err;
188 }
189 if (sLen == RSA_PSS_SALTLEN_MAX) {
190 sLen = emLen - hLen - 2;
191 } else if (sLen > emLen - hLen - 2) {
192 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
193 RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
194 goto err;
195 }
196 if (sLen > 0) {
197 salt = OPENSSL_malloc(sLen);
198 if (salt == NULL) {
199 RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
200 ERR_R_MALLOC_FAILURE);
201 goto err;
202 }
203 if (RAND_bytes(salt, sLen) <= 0)
204 goto err;
205 }
206 maskedDBLen = emLen - hLen - 1;
207 H = EM + maskedDBLen;
208 ctx = EVP_MD_CTX_new();
209 if (ctx == NULL)
210 goto err;
211 if (!EVP_DigestInit_ex(ctx, Hash, NULL)
212 || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
213 || !EVP_DigestUpdate(ctx, mHash, hLen))
214 goto err;
215 if (sLen && !EVP_DigestUpdate(ctx, salt, sLen))
216 goto err;
217 if (!EVP_DigestFinal_ex(ctx, H, NULL))
218 goto err;
219
220 /* Generate dbMask in place then perform XOR on it */
221 if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
222 goto err;
223
224 p = EM;
225
226 /*
227 * Initial PS XORs with all zeroes which is a NOP so just update pointer.
228 * Note from a test above this value is guaranteed to be non-negative.
229 */
230 p += emLen - sLen - hLen - 2;
231 *p++ ^= 0x1;
232 if (sLen > 0) {
233 for (i = 0; i < sLen; i++)
234 *p++ ^= salt[i];
235 }
236 if (MSBits)
237 EM[0] &= 0xFF >> (8 - MSBits);
238
239 /* H is already in place so just set final 0xbc */
240
241 EM[emLen - 1] = 0xbc;
242
243 ret = 1;
244
245 err:
246 EVP_MD_CTX_free(ctx);
247 OPENSSL_clear_free(salt, (size_t)sLen); /* salt != NULL implies sLen > 0 */
248
249 return ret;
250
251}
252
253#if defined(_MSC_VER)
254# pragma optimize("",on)
255#endif
256