Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
| 2 | * All rights reserved. |
| 3 | * |
| 4 | * This package is an SSL implementation written |
| 5 | * by Eric Young (eay@cryptsoft.com). |
| 6 | * The implementation was written so as to conform with Netscapes SSL. |
| 7 | * |
| 8 | * This library is free for commercial and non-commercial use as long as |
| 9 | * the following conditions are aheared to. The following conditions |
| 10 | * apply to all code found in this distribution, be it the RC4, RSA, |
| 11 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
| 12 | * included with this distribution is covered by the same copyright terms |
| 13 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
| 14 | * |
| 15 | * Copyright remains Eric Young's, and as such any Copyright notices in |
| 16 | * the code are not to be removed. |
| 17 | * If this package is used in a product, Eric Young should be given attribution |
| 18 | * as the author of the parts of the library used. |
| 19 | * This can be in the form of a textual message at program startup or |
| 20 | * in documentation (online or textual) provided with the package. |
| 21 | * |
| 22 | * Redistribution and use in source and binary forms, with or without |
| 23 | * modification, are permitted provided that the following conditions |
| 24 | * are met: |
| 25 | * 1. Redistributions of source code must retain the copyright |
| 26 | * notice, this list of conditions and the following disclaimer. |
| 27 | * 2. Redistributions in binary form must reproduce the above copyright |
| 28 | * notice, this list of conditions and the following disclaimer in the |
| 29 | * documentation and/or other materials provided with the distribution. |
| 30 | * 3. All advertising materials mentioning features or use of this software |
| 31 | * must display the following acknowledgement: |
| 32 | * "This product includes cryptographic software written by |
| 33 | * Eric Young (eay@cryptsoft.com)" |
| 34 | * The word 'cryptographic' can be left out if the rouines from the library |
| 35 | * being used are not cryptographic related :-). |
| 36 | * 4. If you include any Windows specific code (or a derivative thereof) from |
| 37 | * the apps directory (application code) you must include an acknowledgement: |
| 38 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
| 39 | * |
| 40 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
| 41 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 43 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 44 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 45 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 46 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 47 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 48 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 49 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 50 | * SUCH DAMAGE. |
| 51 | * |
| 52 | * The licence and distribution terms for any publically available version or |
| 53 | * derivative of this code cannot be changed. i.e. this code cannot simply be |
| 54 | * copied and put under another distribution licence |
| 55 | * [including the GNU Public Licence.] */ |
| 56 | |
| 57 | #include <openssl/rsa.h> |
| 58 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 59 | #include <assert.h> |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 60 | #include <limits.h> |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 61 | #include <string.h> |
| 62 | |
| 63 | #include <openssl/bn.h> |
| 64 | #include <openssl/err.h> |
| 65 | #include <openssl/mem.h> |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 66 | #include <openssl/thread.h> |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 67 | #include <openssl/type_check.h> |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 68 | |
| 69 | #include "internal.h" |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 70 | #include "../bn/internal.h" |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 71 | #include "../../internal.h" |
| 72 | #include "../delocate.h" |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 73 | |
| 74 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 75 | static int check_modulus_and_exponent_sizes(const RSA *rsa) { |
| 76 | unsigned rsa_bits = BN_num_bits(rsa->n); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 77 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 78 | if (rsa_bits > 16 * 1024) { |
| 79 | OPENSSL_PUT_ERROR(RSA, RSA_R_MODULUS_TOO_LARGE); |
| 80 | return 0; |
| 81 | } |
| 82 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 83 | // Mitigate DoS attacks by limiting the exponent size. 33 bits was chosen as |
| 84 | // the limit based on the recommendations in [1] and [2]. Windows CryptoAPI |
| 85 | // doesn't support values larger than 32 bits [3], so it is unlikely that |
| 86 | // exponents larger than 32 bits are being used for anything Windows commonly |
| 87 | // does. |
| 88 | // |
| 89 | // [1] https://www.imperialviolet.org/2012/03/16/rsae.html |
| 90 | // [2] https://www.imperialviolet.org/2012/03/17/rsados.html |
| 91 | // [3] https://msdn.microsoft.com/en-us/library/aa387685(VS.85).aspx |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 92 | static const unsigned kMaxExponentBits = 33; |
| 93 | |
| 94 | if (BN_num_bits(rsa->e) > kMaxExponentBits) { |
| 95 | OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_E_VALUE); |
| 96 | return 0; |
| 97 | } |
| 98 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 99 | // Verify |n > e|. Comparing |rsa_bits| to |kMaxExponentBits| is a small |
| 100 | // shortcut to comparing |n| and |e| directly. In reality, |kMaxExponentBits| |
| 101 | // is much smaller than the minimum RSA key size that any application should |
| 102 | // accept. |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 103 | if (rsa_bits <= kMaxExponentBits) { |
| 104 | OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| 105 | return 0; |
| 106 | } |
| 107 | assert(BN_ucmp(rsa->n, rsa->e) > 0); |
| 108 | |
| 109 | return 1; |
| 110 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 111 | |
Adam Langley | fad6327 | 2015-11-12 12:15:39 -0800 | [diff] [blame] | 112 | size_t rsa_default_size(const RSA *rsa) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 113 | return BN_num_bytes(rsa->n); |
| 114 | } |
| 115 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 116 | int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, |
| 117 | const uint8_t *in, size_t in_len, int padding) { |
| 118 | if (rsa->n == NULL || rsa->e == NULL) { |
| 119 | OPENSSL_PUT_ERROR(RSA, RSA_R_VALUE_MISSING); |
| 120 | return 0; |
| 121 | } |
| 122 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 123 | const unsigned rsa_size = RSA_size(rsa); |
| 124 | BIGNUM *f, *result; |
| 125 | uint8_t *buf = NULL; |
| 126 | BN_CTX *ctx = NULL; |
| 127 | int i, ret = 0; |
| 128 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 129 | if (max_out < rsa_size) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 130 | OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 131 | return 0; |
| 132 | } |
| 133 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 134 | if (!check_modulus_and_exponent_sizes(rsa)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | ctx = BN_CTX_new(); |
| 139 | if (ctx == NULL) { |
| 140 | goto err; |
| 141 | } |
| 142 | |
| 143 | BN_CTX_start(ctx); |
| 144 | f = BN_CTX_get(ctx); |
| 145 | result = BN_CTX_get(ctx); |
| 146 | buf = OPENSSL_malloc(rsa_size); |
| 147 | if (!f || !result || !buf) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 148 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 149 | goto err; |
| 150 | } |
| 151 | |
| 152 | switch (padding) { |
| 153 | case RSA_PKCS1_PADDING: |
| 154 | i = RSA_padding_add_PKCS1_type_2(buf, rsa_size, in, in_len); |
| 155 | break; |
| 156 | case RSA_PKCS1_OAEP_PADDING: |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 157 | // Use the default parameters: SHA-1 for both hashes and no label. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 158 | i = RSA_padding_add_PKCS1_OAEP_mgf1(buf, rsa_size, in, in_len, |
| 159 | NULL, 0, NULL, NULL); |
| 160 | break; |
| 161 | case RSA_NO_PADDING: |
| 162 | i = RSA_padding_add_none(buf, rsa_size, in, in_len); |
| 163 | break; |
| 164 | default: |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 165 | OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 166 | goto err; |
| 167 | } |
| 168 | |
| 169 | if (i <= 0) { |
| 170 | goto err; |
| 171 | } |
| 172 | |
| 173 | if (BN_bin2bn(buf, rsa_size, f) == NULL) { |
| 174 | goto err; |
| 175 | } |
| 176 | |
| 177 | if (BN_ucmp(f, rsa->n) >= 0) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 178 | // usually the padding functions would catch this |
Robert Sloan | f6200e7 | 2017-07-10 08:09:18 -0700 | [diff] [blame] | 179 | OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 180 | goto err; |
| 181 | } |
| 182 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 183 | if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx) || |
| 184 | !BN_mod_exp_mont(result, f, rsa->e, rsa->n, ctx, rsa->mont_n)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 185 | goto err; |
| 186 | } |
| 187 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 188 | // put in leading 0 bytes if the number is less than the length of the |
| 189 | // modulus |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 190 | if (!BN_bn2bin_padded(out, rsa_size, result)) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 191 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 192 | goto err; |
| 193 | } |
| 194 | |
| 195 | *out_len = rsa_size; |
| 196 | ret = 1; |
| 197 | |
| 198 | err: |
| 199 | if (ctx != NULL) { |
| 200 | BN_CTX_end(ctx); |
| 201 | BN_CTX_free(ctx); |
| 202 | } |
Robert Sloan | 2e9e66a | 2017-09-25 09:08:29 -0700 | [diff] [blame] | 203 | OPENSSL_free(buf); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 204 | |
| 205 | return ret; |
| 206 | } |
| 207 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 208 | // MAX_BLINDINGS_PER_RSA defines the maximum number of cached BN_BLINDINGs per |
| 209 | // RSA*. Then this limit is exceeded, BN_BLINDING objects will be created and |
| 210 | // destroyed as needed. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 211 | #define MAX_BLINDINGS_PER_RSA 1024 |
| 212 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 213 | // rsa_blinding_get returns a BN_BLINDING to use with |rsa|. It does this by |
| 214 | // allocating one of the cached BN_BLINDING objects in |rsa->blindings|. If |
| 215 | // none are free, the cache will be extended by a extra element and the new |
| 216 | // BN_BLINDING is returned. |
| 217 | // |
| 218 | // On success, the index of the assigned BN_BLINDING is written to |
| 219 | // |*index_used| and must be passed to |rsa_blinding_release| when finished. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 220 | static BN_BLINDING *rsa_blinding_get(RSA *rsa, unsigned *index_used, |
| 221 | BN_CTX *ctx) { |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 222 | assert(ctx != NULL); |
| 223 | assert(rsa->mont_n != NULL); |
| 224 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 225 | BN_BLINDING *ret = NULL; |
| 226 | BN_BLINDING **new_blindings; |
| 227 | uint8_t *new_blindings_inuse; |
| 228 | char overflow = 0; |
| 229 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 230 | CRYPTO_MUTEX_lock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 231 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 232 | unsigned i; |
| 233 | for (i = 0; i < rsa->num_blindings; i++) { |
| 234 | if (rsa->blindings_inuse[i] == 0) { |
| 235 | rsa->blindings_inuse[i] = 1; |
| 236 | ret = rsa->blindings[i]; |
| 237 | *index_used = i; |
| 238 | break; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 239 | } |
| 240 | } |
| 241 | |
| 242 | if (ret != NULL) { |
David Benjamin | d316cba | 2016-06-02 16:17:39 -0400 | [diff] [blame] | 243 | CRYPTO_MUTEX_unlock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 244 | return ret; |
| 245 | } |
| 246 | |
| 247 | overflow = rsa->num_blindings >= MAX_BLINDINGS_PER_RSA; |
| 248 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 249 | // We didn't find a free BN_BLINDING to use so increase the length of |
| 250 | // the arrays by one and use the newly created element. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 251 | |
David Benjamin | d316cba | 2016-06-02 16:17:39 -0400 | [diff] [blame] | 252 | CRYPTO_MUTEX_unlock_write(&rsa->lock); |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 253 | ret = BN_BLINDING_new(); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 254 | if (ret == NULL) { |
| 255 | return NULL; |
| 256 | } |
| 257 | |
| 258 | if (overflow) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 259 | // We cannot add any more cached BN_BLINDINGs so we use |ret| |
| 260 | // and mark it for destruction in |rsa_blinding_release|. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 261 | *index_used = MAX_BLINDINGS_PER_RSA; |
| 262 | return ret; |
| 263 | } |
| 264 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 265 | CRYPTO_MUTEX_lock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 266 | |
| 267 | new_blindings = |
| 268 | OPENSSL_malloc(sizeof(BN_BLINDING *) * (rsa->num_blindings + 1)); |
| 269 | if (new_blindings == NULL) { |
| 270 | goto err1; |
| 271 | } |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 272 | OPENSSL_memcpy(new_blindings, rsa->blindings, |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 273 | sizeof(BN_BLINDING *) * rsa->num_blindings); |
| 274 | new_blindings[rsa->num_blindings] = ret; |
| 275 | |
| 276 | new_blindings_inuse = OPENSSL_malloc(rsa->num_blindings + 1); |
| 277 | if (new_blindings_inuse == NULL) { |
| 278 | goto err2; |
| 279 | } |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 280 | OPENSSL_memcpy(new_blindings_inuse, rsa->blindings_inuse, rsa->num_blindings); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 281 | new_blindings_inuse[rsa->num_blindings] = 1; |
| 282 | *index_used = rsa->num_blindings; |
| 283 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 284 | OPENSSL_free(rsa->blindings); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 285 | rsa->blindings = new_blindings; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 286 | OPENSSL_free(rsa->blindings_inuse); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 287 | rsa->blindings_inuse = new_blindings_inuse; |
| 288 | rsa->num_blindings++; |
| 289 | |
David Benjamin | d316cba | 2016-06-02 16:17:39 -0400 | [diff] [blame] | 290 | CRYPTO_MUTEX_unlock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 291 | return ret; |
| 292 | |
| 293 | err2: |
| 294 | OPENSSL_free(new_blindings); |
| 295 | |
| 296 | err1: |
David Benjamin | d316cba | 2016-06-02 16:17:39 -0400 | [diff] [blame] | 297 | CRYPTO_MUTEX_unlock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 298 | BN_BLINDING_free(ret); |
| 299 | return NULL; |
| 300 | } |
| 301 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 302 | // rsa_blinding_release marks the cached BN_BLINDING at the given index as free |
| 303 | // for other threads to use. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 304 | static void rsa_blinding_release(RSA *rsa, BN_BLINDING *blinding, |
| 305 | unsigned blinding_index) { |
| 306 | if (blinding_index == MAX_BLINDINGS_PER_RSA) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 307 | // This blinding wasn't cached. |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 308 | BN_BLINDING_free(blinding); |
| 309 | return; |
| 310 | } |
| 311 | |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 312 | CRYPTO_MUTEX_lock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 313 | rsa->blindings_inuse[blinding_index] = 0; |
David Benjamin | d316cba | 2016-06-02 16:17:39 -0400 | [diff] [blame] | 314 | CRYPTO_MUTEX_unlock_write(&rsa->lock); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 315 | } |
| 316 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 317 | // signing |
Adam Langley | fad6327 | 2015-11-12 12:15:39 -0800 | [diff] [blame] | 318 | int rsa_default_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out, |
| 319 | size_t max_out, const uint8_t *in, size_t in_len, |
| 320 | int padding) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 321 | const unsigned rsa_size = RSA_size(rsa); |
| 322 | uint8_t *buf = NULL; |
| 323 | int i, ret = 0; |
| 324 | |
| 325 | if (max_out < rsa_size) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 326 | OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 327 | return 0; |
| 328 | } |
| 329 | |
| 330 | buf = OPENSSL_malloc(rsa_size); |
| 331 | if (buf == NULL) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 332 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 333 | goto err; |
| 334 | } |
| 335 | |
| 336 | switch (padding) { |
| 337 | case RSA_PKCS1_PADDING: |
| 338 | i = RSA_padding_add_PKCS1_type_1(buf, rsa_size, in, in_len); |
| 339 | break; |
| 340 | case RSA_NO_PADDING: |
| 341 | i = RSA_padding_add_none(buf, rsa_size, in, in_len); |
| 342 | break; |
| 343 | default: |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 344 | OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 345 | goto err; |
| 346 | } |
| 347 | |
| 348 | if (i <= 0) { |
| 349 | goto err; |
| 350 | } |
| 351 | |
| 352 | if (!RSA_private_transform(rsa, out, buf, rsa_size)) { |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 353 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 354 | } |
| 355 | |
| 356 | *out_len = rsa_size; |
| 357 | ret = 1; |
| 358 | |
| 359 | err: |
Robert Sloan | 2e9e66a | 2017-09-25 09:08:29 -0700 | [diff] [blame] | 360 | OPENSSL_free(buf); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 361 | |
| 362 | return ret; |
| 363 | } |
| 364 | |
Adam Langley | fad6327 | 2015-11-12 12:15:39 -0800 | [diff] [blame] | 365 | int rsa_default_decrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, |
| 366 | const uint8_t *in, size_t in_len, int padding) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 367 | const unsigned rsa_size = RSA_size(rsa); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 368 | uint8_t *buf = NULL; |
| 369 | int ret = 0; |
| 370 | |
| 371 | if (max_out < rsa_size) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 372 | OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 373 | return 0; |
| 374 | } |
| 375 | |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 376 | if (padding == RSA_NO_PADDING) { |
| 377 | buf = out; |
| 378 | } else { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 379 | // Allocate a temporary buffer to hold the padded plaintext. |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 380 | buf = OPENSSL_malloc(rsa_size); |
| 381 | if (buf == NULL) { |
| 382 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| 383 | goto err; |
| 384 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 385 | } |
| 386 | |
| 387 | if (in_len != rsa_size) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 388 | OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 389 | goto err; |
| 390 | } |
| 391 | |
| 392 | if (!RSA_private_transform(rsa, buf, in, rsa_size)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 393 | goto err; |
| 394 | } |
| 395 | |
| 396 | switch (padding) { |
| 397 | case RSA_PKCS1_PADDING: |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 398 | ret = |
| 399 | RSA_padding_check_PKCS1_type_2(out, out_len, rsa_size, buf, rsa_size); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 400 | break; |
| 401 | case RSA_PKCS1_OAEP_PADDING: |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 402 | // Use the default parameters: SHA-1 for both hashes and no label. |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 403 | ret = RSA_padding_check_PKCS1_OAEP_mgf1(out, out_len, rsa_size, buf, |
| 404 | rsa_size, NULL, 0, NULL, NULL); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 405 | break; |
| 406 | case RSA_NO_PADDING: |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 407 | *out_len = rsa_size; |
| 408 | ret = 1; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 409 | break; |
| 410 | default: |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 411 | OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 412 | goto err; |
| 413 | } |
| 414 | |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 415 | if (!ret) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 416 | OPENSSL_PUT_ERROR(RSA, RSA_R_PADDING_CHECK_FAILED); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 417 | } |
| 418 | |
| 419 | err: |
Robert Sloan | 2e9e66a | 2017-09-25 09:08:29 -0700 | [diff] [blame] | 420 | if (padding != RSA_NO_PADDING) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 421 | OPENSSL_free(buf); |
| 422 | } |
| 423 | |
| 424 | return ret; |
| 425 | } |
| 426 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 427 | static int mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx); |
| 428 | |
| 429 | int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, |
| 430 | const uint8_t *in, size_t in_len, int padding) { |
| 431 | if (rsa->n == NULL || rsa->e == NULL) { |
| 432 | OPENSSL_PUT_ERROR(RSA, RSA_R_VALUE_MISSING); |
| 433 | return 0; |
| 434 | } |
| 435 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 436 | const unsigned rsa_size = RSA_size(rsa); |
| 437 | BIGNUM *f, *result; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 438 | |
| 439 | if (max_out < rsa_size) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 440 | OPENSSL_PUT_ERROR(RSA, RSA_R_OUTPUT_BUFFER_TOO_SMALL); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 441 | return 0; |
| 442 | } |
| 443 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 444 | if (in_len != rsa_size) { |
| 445 | OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_LEN_NOT_EQUAL_TO_MOD_LEN); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 446 | return 0; |
| 447 | } |
| 448 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 449 | if (!check_modulus_and_exponent_sizes(rsa)) { |
| 450 | return 0; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 451 | } |
| 452 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 453 | BN_CTX *ctx = BN_CTX_new(); |
| 454 | if (ctx == NULL) { |
| 455 | return 0; |
| 456 | } |
| 457 | |
| 458 | int ret = 0; |
| 459 | uint8_t *buf = NULL; |
| 460 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 461 | BN_CTX_start(ctx); |
| 462 | f = BN_CTX_get(ctx); |
| 463 | result = BN_CTX_get(ctx); |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 464 | if (f == NULL || result == NULL) { |
| 465 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| 466 | goto err; |
| 467 | } |
| 468 | |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 469 | if (padding == RSA_NO_PADDING) { |
| 470 | buf = out; |
| 471 | } else { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 472 | // Allocate a temporary buffer to hold the padded plaintext. |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 473 | buf = OPENSSL_malloc(rsa_size); |
| 474 | if (buf == NULL) { |
| 475 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| 476 | goto err; |
| 477 | } |
| 478 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 479 | |
| 480 | if (BN_bin2bn(in, in_len, f) == NULL) { |
| 481 | goto err; |
| 482 | } |
| 483 | |
| 484 | if (BN_ucmp(f, rsa->n) >= 0) { |
Robert Sloan | f6200e7 | 2017-07-10 08:09:18 -0700 | [diff] [blame] | 485 | OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 486 | goto err; |
| 487 | } |
| 488 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 489 | if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx) || |
| 490 | !BN_mod_exp_mont(result, f, rsa->e, rsa->n, ctx, rsa->mont_n)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 491 | goto err; |
| 492 | } |
| 493 | |
| 494 | if (!BN_bn2bin_padded(buf, rsa_size, result)) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 495 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 496 | goto err; |
| 497 | } |
| 498 | |
| 499 | switch (padding) { |
| 500 | case RSA_PKCS1_PADDING: |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 501 | ret = |
| 502 | RSA_padding_check_PKCS1_type_1(out, out_len, rsa_size, buf, rsa_size); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 503 | break; |
| 504 | case RSA_NO_PADDING: |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 505 | ret = 1; |
| 506 | *out_len = rsa_size; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 507 | break; |
| 508 | default: |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 509 | OPENSSL_PUT_ERROR(RSA, RSA_R_UNKNOWN_PADDING_TYPE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 510 | goto err; |
| 511 | } |
| 512 | |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 513 | if (!ret) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 514 | OPENSSL_PUT_ERROR(RSA, RSA_R_PADDING_CHECK_FAILED); |
Robert Sloan | 6f79a50 | 2017-04-03 09:16:40 -0700 | [diff] [blame] | 515 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 516 | } |
| 517 | |
| 518 | err: |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 519 | BN_CTX_end(ctx); |
| 520 | BN_CTX_free(ctx); |
| 521 | if (buf != out) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 522 | OPENSSL_free(buf); |
| 523 | } |
| 524 | return ret; |
| 525 | } |
| 526 | |
Adam Langley | fad6327 | 2015-11-12 12:15:39 -0800 | [diff] [blame] | 527 | int rsa_default_private_transform(RSA *rsa, uint8_t *out, const uint8_t *in, |
| 528 | size_t len) { |
Robert Sloan | e56da3e | 2017-06-26 08:26:42 -0700 | [diff] [blame] | 529 | if (rsa->n == NULL || rsa->d == NULL) { |
| 530 | OPENSSL_PUT_ERROR(RSA, RSA_R_VALUE_MISSING); |
| 531 | return 0; |
| 532 | } |
| 533 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 534 | BIGNUM *f, *result; |
| 535 | BN_CTX *ctx = NULL; |
| 536 | unsigned blinding_index = 0; |
| 537 | BN_BLINDING *blinding = NULL; |
| 538 | int ret = 0; |
| 539 | |
| 540 | ctx = BN_CTX_new(); |
| 541 | if (ctx == NULL) { |
| 542 | goto err; |
| 543 | } |
| 544 | BN_CTX_start(ctx); |
| 545 | f = BN_CTX_get(ctx); |
| 546 | result = BN_CTX_get(ctx); |
| 547 | |
| 548 | if (f == NULL || result == NULL) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 549 | OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 550 | goto err; |
| 551 | } |
| 552 | |
| 553 | if (BN_bin2bn(in, len, f) == NULL) { |
| 554 | goto err; |
| 555 | } |
| 556 | |
| 557 | if (BN_ucmp(f, rsa->n) >= 0) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 558 | // Usually the padding functions would catch this. |
Robert Sloan | f6200e7 | 2017-07-10 08:09:18 -0700 | [diff] [blame] | 559 | OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 560 | goto err; |
| 561 | } |
| 562 | |
David Benjamin | 9aaebef | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 563 | if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx)) { |
| 564 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
| 565 | goto err; |
| 566 | } |
| 567 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 568 | const int do_blinding = (rsa->flags & RSA_FLAG_NO_BLINDING) == 0; |
David Benjamin | 9aaebef | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 569 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 570 | if (rsa->e == NULL && do_blinding) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 571 | // We cannot do blinding or verification without |e|, and continuing without |
| 572 | // those countermeasures is dangerous. However, the Java/Android RSA API |
| 573 | // requires support for keys where only |d| and |n| (and not |e|) are known. |
| 574 | // The callers that require that bad behavior set |RSA_FLAG_NO_BLINDING|. |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 575 | OPENSSL_PUT_ERROR(RSA, RSA_R_NO_PUBLIC_EXPONENT); |
| 576 | goto err; |
| 577 | } |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 578 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 579 | if (do_blinding) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 580 | blinding = rsa_blinding_get(rsa, &blinding_index, ctx); |
| 581 | if (blinding == NULL) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 582 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 583 | goto err; |
| 584 | } |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 585 | if (!BN_BLINDING_convert(f, blinding, rsa->e, rsa->mont_n, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 586 | goto err; |
| 587 | } |
| 588 | } |
| 589 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 590 | if (rsa->p != NULL && rsa->q != NULL && rsa->e != NULL && rsa->dmp1 != NULL && |
| 591 | rsa->dmq1 != NULL && rsa->iqmp != NULL) { |
| 592 | if (!mod_exp(result, f, rsa, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 593 | goto err; |
| 594 | } |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 595 | } else if (!BN_mod_exp_mont_consttime(result, f, rsa->d, rsa->n, ctx, |
| 596 | rsa->mont_n)) { |
| 597 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 598 | } |
| 599 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 600 | // Verify the result to protect against fault attacks as described in the |
| 601 | // 1997 paper "On the Importance of Checking Cryptographic Protocols for |
| 602 | // Faults" by Dan Boneh, Richard A. DeMillo, and Richard J. Lipton. Some |
| 603 | // implementations do this only when the CRT is used, but we do it in all |
| 604 | // cases. Section 6 of the aforementioned paper describes an attack that |
| 605 | // works when the CRT isn't used. That attack is much less likely to succeed |
| 606 | // than the CRT attack, but there have likely been improvements since 1997. |
| 607 | // |
| 608 | // This check is cheap assuming |e| is small; it almost always is. |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 609 | if (rsa->e != NULL) { |
David Benjamin | 9aaebef | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 610 | BIGNUM *vrfy = BN_CTX_get(ctx); |
| 611 | if (vrfy == NULL || |
| 612 | !BN_mod_exp_mont(vrfy, result, rsa->e, rsa->n, ctx, rsa->mont_n) || |
| 613 | !BN_equal_consttime(vrfy, f)) { |
| 614 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
| 615 | goto err; |
| 616 | } |
| 617 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 618 | } |
| 619 | |
| 620 | if (do_blinding && |
| 621 | !BN_BLINDING_invert(result, blinding, rsa->mont_n, ctx)) { |
| 622 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 623 | } |
| 624 | |
| 625 | if (!BN_bn2bin_padded(out, len, result)) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 626 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 627 | goto err; |
| 628 | } |
| 629 | |
| 630 | ret = 1; |
| 631 | |
| 632 | err: |
| 633 | if (ctx != NULL) { |
| 634 | BN_CTX_end(ctx); |
| 635 | BN_CTX_free(ctx); |
| 636 | } |
| 637 | if (blinding != NULL) { |
| 638 | rsa_blinding_release(rsa, blinding, blinding_index); |
| 639 | } |
| 640 | |
| 641 | return ret; |
| 642 | } |
| 643 | |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 644 | // mod_montgomery sets |r| to |I| mod |p|. |I| must already be fully reduced |
| 645 | // modulo |p| times |q|. It returns one on success and zero on error. |
| 646 | static int mod_montgomery(BIGNUM *r, const BIGNUM *I, const BIGNUM *p, |
| 647 | const BN_MONT_CTX *mont_p, const BIGNUM *q, |
| 648 | BN_CTX *ctx) { |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 649 | // Reducing in constant-time with Montgomery reduction requires I <= p * R. We |
| 650 | // have I < p * q, so this follows if q < R. In particular, this always holds |
| 651 | // if p and q are the same size, which is true for any RSA keys we or anyone |
| 652 | // sane generates. For other keys, we fall back to |BN_mod|. |
| 653 | if (!bn_less_than_montgomery_R(q, mont_p)) { |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 654 | return BN_mod(r, I, p, ctx); |
| 655 | } |
| 656 | |
| 657 | if (// Reduce mod p with Montgomery reduction. This computes I * R^-1 mod p. |
| 658 | !BN_from_montgomery(r, I, mont_p, ctx) || |
| 659 | // Multiply by R^2 and do another Montgomery reduction to compute |
| 660 | // I * R^-1 * R^2 * R^-1 = I mod p. |
| 661 | !BN_to_montgomery(r, r, mont_p, ctx)) { |
| 662 | return 0; |
| 663 | } |
| 664 | |
| 665 | // By precomputing R^3 mod p (normally |BN_MONT_CTX| only uses R^2 mod p) and |
| 666 | // adjusting the API for |BN_mod_exp_mont_consttime|, we could instead compute |
| 667 | // I * R mod p here and save a reduction per prime. But this would require |
| 668 | // changing the RSAZ code and may not be worth it. |
| 669 | return 1; |
| 670 | } |
| 671 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 672 | static int mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) { |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 673 | assert(ctx != NULL); |
| 674 | |
| 675 | assert(rsa->n != NULL); |
| 676 | assert(rsa->e != NULL); |
| 677 | assert(rsa->d != NULL); |
| 678 | assert(rsa->p != NULL); |
| 679 | assert(rsa->q != NULL); |
| 680 | assert(rsa->dmp1 != NULL); |
| 681 | assert(rsa->dmq1 != NULL); |
| 682 | assert(rsa->iqmp != NULL); |
| 683 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 684 | BIGNUM *r1, *m1, *vrfy; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 685 | int ret = 0; |
| 686 | |
| 687 | BN_CTX_start(ctx); |
| 688 | r1 = BN_CTX_get(ctx); |
| 689 | m1 = BN_CTX_get(ctx); |
| 690 | vrfy = BN_CTX_get(ctx); |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 691 | if (r1 == NULL || |
| 692 | m1 == NULL || |
| 693 | vrfy == NULL) { |
| 694 | goto err; |
| 695 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 696 | |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 697 | if (!BN_MONT_CTX_set_locked(&rsa->mont_p, &rsa->lock, rsa->p, ctx) || |
| 698 | !BN_MONT_CTX_set_locked(&rsa->mont_q, &rsa->lock, rsa->q, ctx)) { |
| 699 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 700 | } |
| 701 | |
David Benjamin | 4969cc9 | 2016-04-22 15:02:23 -0400 | [diff] [blame] | 702 | if (!BN_MONT_CTX_set_locked(&rsa->mont_n, &rsa->lock, rsa->n, ctx)) { |
| 703 | goto err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 704 | } |
| 705 | |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 706 | // This is a pre-condition for |mod_montgomery|. It was already checked by the |
| 707 | // caller. |
| 708 | assert(BN_ucmp(I, rsa->n) < 0); |
| 709 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 710 | // compute I mod q |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 711 | if (!mod_montgomery(r1, I, rsa->q, rsa->mont_q, rsa->p, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 712 | goto err; |
| 713 | } |
| 714 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 715 | // compute r1^dmq1 mod q |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 716 | if (!BN_mod_exp_mont_consttime(m1, r1, rsa->dmq1, rsa->q, ctx, rsa->mont_q)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 717 | goto err; |
| 718 | } |
| 719 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 720 | // compute I mod p |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 721 | if (!mod_montgomery(r1, I, rsa->p, rsa->mont_p, rsa->q, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 722 | goto err; |
| 723 | } |
| 724 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 725 | // compute r1^dmp1 mod p |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 726 | if (!BN_mod_exp_mont_consttime(r0, r1, rsa->dmp1, rsa->p, ctx, rsa->mont_p)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 727 | goto err; |
| 728 | } |
| 729 | |
Robert Sloan | 5581810 | 2017-12-18 11:26:17 -0800 | [diff] [blame] | 730 | // TODO(davidben): The code below is not constant-time, even ignoring |
| 731 | // |bn_correct_top|. To fix this: |
| 732 | // |
| 733 | // 1. Canonicalize keys on p > q. (p > q for keys we generate, but not ones we |
| 734 | // import.) We have exposed structs, but we can generalize the |
| 735 | // |BN_MONT_CTX_set_locked| trick to do a one-time canonicalization of the |
| 736 | // private key where we optionally swap p and q (re-computing iqmp if |
| 737 | // necessary) and fill in mont_*. This removes the p < q case below. |
| 738 | // |
| 739 | // 2. Compute r0 - m1 (mod p) in constant-time. With (1) done, this is just a |
| 740 | // constant-time modular subtraction. It should be doable with |
| 741 | // |bn_sub_words| and a select on the borrow bit. |
| 742 | // |
| 743 | // 3. When computing mont_*, additionally compute iqmp_mont, iqmp in |
| 744 | // Montgomery form. The |BN_mul| and |BN_mod| pair can then be replaced |
| 745 | // with |BN_mod_mul_montgomery|. |
| 746 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 747 | if (!BN_sub(r0, r0, m1)) { |
| 748 | goto err; |
| 749 | } |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 750 | // This will help stop the size of r0 increasing, which does |
| 751 | // affect the multiply if it optimised for a power of 2 size |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 752 | if (BN_is_negative(r0)) { |
| 753 | if (!BN_add(r0, r0, rsa->p)) { |
| 754 | goto err; |
| 755 | } |
| 756 | } |
| 757 | |
| 758 | if (!BN_mul(r1, r0, rsa->iqmp, ctx)) { |
| 759 | goto err; |
| 760 | } |
| 761 | |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 762 | if (!BN_mod(r0, r1, rsa->p, ctx)) { |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 763 | goto err; |
| 764 | } |
| 765 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 766 | // If p < q it is occasionally possible for the correction of |
| 767 | // adding 'p' if r0 is negative above to leave the result still |
| 768 | // negative. This can break the private key operations: the following |
| 769 | // second correction should *always* correct this rare occurrence. |
| 770 | // This will *never* happen with OpenSSL generated keys because |
| 771 | // they ensure p > q [steve] |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 772 | if (BN_is_negative(r0)) { |
| 773 | if (!BN_add(r0, r0, rsa->p)) { |
| 774 | goto err; |
| 775 | } |
| 776 | } |
| 777 | if (!BN_mul(r1, r0, rsa->q, ctx)) { |
| 778 | goto err; |
| 779 | } |
| 780 | if (!BN_add(r0, r1, m1)) { |
| 781 | goto err; |
| 782 | } |
| 783 | |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 784 | ret = 1; |
| 785 | |
| 786 | err: |
| 787 | BN_CTX_end(ctx); |
| 788 | return ret; |
| 789 | } |
| 790 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 791 | static int ensure_bignum(BIGNUM **out) { |
| 792 | if (*out == NULL) { |
| 793 | *out = BN_new(); |
| 794 | } |
| 795 | return *out != NULL; |
| 796 | } |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 797 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 798 | // kBoringSSLRSASqrtTwo is the BIGNUM representation of ⌊2¹⁵³⁵×√2⌋. This is |
| 799 | // chosen to give enough precision for 3072-bit RSA, the largest key size FIPS |
| 800 | // specifies. Key sizes beyond this will round up. |
| 801 | // |
| 802 | // To verify this number, check that n² < 2³⁰⁷¹ < (n+1)², where n is value |
| 803 | // represented here. Note the components are listed in little-endian order. Here |
| 804 | // is some sample Python code to check: |
| 805 | // |
| 806 | // >>> TOBN = lambda a, b: a << 32 | b |
| 807 | // >>> l = [ <paste the contents of kSqrtTwo> ] |
| 808 | // >>> n = sum(a * 2**(64*i) for i, a in enumerate(l)) |
| 809 | // >>> n**2 < 2**3071 < (n+1)**2 |
| 810 | // True |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 811 | const BN_ULONG kBoringSSLRSASqrtTwo[] = { |
| 812 | TOBN(0xdea06241, 0xf7aa81c2), TOBN(0xf6a1be3f, 0xca221307), |
| 813 | TOBN(0x332a5e9f, 0x7bda1ebf), TOBN(0x0104dc01, 0xfe32352f), |
| 814 | TOBN(0xb8cf341b, 0x6f8236c7), TOBN(0x4264dabc, 0xd528b651), |
| 815 | TOBN(0xf4d3a02c, 0xebc93e0c), TOBN(0x81394ab6, 0xd8fd0efd), |
| 816 | TOBN(0xeaa4a089, 0x9040ca4a), TOBN(0xf52f120f, 0x836e582e), |
| 817 | TOBN(0xcb2a6343, 0x31f3c84d), TOBN(0xc6d5a8a3, 0x8bb7e9dc), |
| 818 | TOBN(0x460abc72, 0x2f7c4e33), TOBN(0xcab1bc91, 0x1688458a), |
| 819 | TOBN(0x53059c60, 0x11bc337b), TOBN(0xd2202e87, 0x42af1f4e), |
| 820 | TOBN(0x78048736, 0x3dfa2768), TOBN(0x0f74a85e, 0x439c7b4a), |
| 821 | TOBN(0xa8b1fe6f, 0xdc83db39), TOBN(0x4afc8304, 0x3ab8a2c3), |
| 822 | TOBN(0xed17ac85, 0x83339915), TOBN(0x1d6f60ba, 0x893ba84c), |
| 823 | TOBN(0x597d89b3, 0x754abe9f), TOBN(0xb504f333, 0xf9de6484), |
| 824 | }; |
| 825 | const size_t kBoringSSLRSASqrtTwoLen = OPENSSL_ARRAY_SIZE(kBoringSSLRSASqrtTwo); |
| 826 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 827 | int rsa_greater_than_pow2(const BIGNUM *b, int n) { |
| 828 | if (BN_is_negative(b) || n == INT_MAX) { |
| 829 | return 0; |
| 830 | } |
| 831 | |
| 832 | int b_bits = BN_num_bits(b); |
| 833 | return b_bits > n + 1 || (b_bits == n + 1 && !BN_is_pow2(b)); |
| 834 | } |
| 835 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 836 | // generate_prime sets |out| to a prime with length |bits| such that |out|-1 is |
| 837 | // relatively prime to |e|. If |p| is non-NULL, |out| will also not be close to |
| 838 | // |p|. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 839 | static int generate_prime(BIGNUM *out, int bits, const BIGNUM *e, |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 840 | const BIGNUM *p, const BIGNUM *sqrt2, BN_CTX *ctx, |
| 841 | BN_GENCB *cb) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 842 | if (bits < 128 || (bits % BN_BITS2) != 0) { |
| 843 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
| 844 | return 0; |
| 845 | } |
| 846 | |
Robert Sloan | b1b54b8 | 2017-11-06 13:50:02 -0800 | [diff] [blame] | 847 | // See FIPS 186-4 appendix B.3.3, steps 4 and 5. Note |bits| here is nlen/2. |
| 848 | |
| 849 | // Use the limit from steps 4.7 and 5.8 for most values of |e|. When |e| is 3, |
| 850 | // the 186-4 limit is too low, so we use a higher one. Note this case is not |
| 851 | // reachable from |RSA_generate_key_fips|. |
| 852 | if (bits >= INT_MAX/32) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 853 | OPENSSL_PUT_ERROR(RSA, RSA_R_MODULUS_TOO_LARGE); |
| 854 | return 0; |
| 855 | } |
Robert Sloan | b1b54b8 | 2017-11-06 13:50:02 -0800 | [diff] [blame] | 856 | int limit = BN_is_word(e, 3) ? bits * 32 : bits * 5; |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 857 | |
| 858 | int ret = 0, tries = 0, rand_tries = 0; |
| 859 | BN_CTX_start(ctx); |
| 860 | BIGNUM *tmp = BN_CTX_get(ctx); |
| 861 | if (tmp == NULL) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 862 | goto err; |
| 863 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 864 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 865 | for (;;) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 866 | // Generate a random number of length |bits| where the bottom bit is set |
| 867 | // (steps 4.2, 4.3, 5.2 and 5.3) and the top bit is set (implied by the |
| 868 | // bound checked below in steps 4.4 and 5.5). |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 869 | if (!BN_rand(out, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD) || |
| 870 | !BN_GENCB_call(cb, BN_GENCB_GENERATED, rand_tries++)) { |
| 871 | goto err; |
| 872 | } |
| 873 | |
| 874 | if (p != NULL) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 875 | // If |p| and |out| are too close, try again (step 5.4). |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 876 | if (!BN_sub(tmp, out, p)) { |
| 877 | goto err; |
| 878 | } |
| 879 | BN_set_negative(tmp, 0); |
| 880 | if (!rsa_greater_than_pow2(tmp, bits - 100)) { |
| 881 | continue; |
| 882 | } |
| 883 | } |
| 884 | |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 885 | // If out < 2^(bits-1)×√2, try again (steps 4.4 and 5.5). This is equivalent |
| 886 | // to out <= ⌊2^(bits-1)×√2⌋, or out <= sqrt2 for FIPS key sizes. |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 887 | // |
| 888 | // For larger keys, the comparison is approximate, leaning towards |
| 889 | // retrying. That is, we reject a negligible fraction of primes that are |
| 890 | // within the FIPS bound, but we will never accept a prime outside the |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 891 | // bound, ensuring the resulting RSA key is the right size. |
| 892 | if (!BN_less_than_consttime(sqrt2, out)) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 893 | continue; |
| 894 | } |
| 895 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 896 | // Check gcd(out-1, e) is one (steps 4.5 and 5.6). |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 897 | if (!BN_sub(tmp, out, BN_value_one()) || |
| 898 | !BN_gcd(tmp, tmp, e, ctx)) { |
| 899 | goto err; |
| 900 | } |
| 901 | if (BN_is_one(tmp)) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 902 | // Test |out| for primality (steps 4.5.1 and 5.6.1). |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 903 | int is_probable_prime; |
| 904 | if (!BN_primality_test(&is_probable_prime, out, BN_prime_checks, ctx, 1, |
| 905 | cb)) { |
| 906 | goto err; |
| 907 | } |
| 908 | if (is_probable_prime) { |
| 909 | ret = 1; |
| 910 | goto err; |
| 911 | } |
| 912 | } |
| 913 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 914 | // If we've tried too many times to find a prime, abort (steps 4.7 and |
| 915 | // 5.8). |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 916 | tries++; |
Robert Sloan | b1b54b8 | 2017-11-06 13:50:02 -0800 | [diff] [blame] | 917 | if (tries >= limit) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 918 | OPENSSL_PUT_ERROR(RSA, RSA_R_TOO_MANY_ITERATIONS); |
| 919 | goto err; |
| 920 | } |
| 921 | if (!BN_GENCB_call(cb, 2, tries)) { |
| 922 | goto err; |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | err: |
| 927 | BN_CTX_end(ctx); |
| 928 | return ret; |
| 929 | } |
| 930 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 931 | int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 932 | // See FIPS 186-4 appendix B.3. This function implements a generalized version |
| 933 | // of the FIPS algorithm. |RSA_generate_key_fips| performs additional checks |
| 934 | // for FIPS-compliant key generation. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 935 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 936 | // Always generate RSA keys which are a multiple of 128 bits. Round |bits| |
| 937 | // down as needed. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 938 | bits &= ~127; |
| 939 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 940 | // Reject excessively small keys. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 941 | if (bits < 256) { |
| 942 | OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| 943 | return 0; |
| 944 | } |
| 945 | |
| 946 | int ret = 0; |
| 947 | BN_CTX *ctx = BN_CTX_new(); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 948 | if (ctx == NULL) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 949 | goto bn_err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 950 | } |
| 951 | BN_CTX_start(ctx); |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 952 | BIGNUM *totient = BN_CTX_get(ctx); |
| 953 | BIGNUM *pm1 = BN_CTX_get(ctx); |
| 954 | BIGNUM *qm1 = BN_CTX_get(ctx); |
| 955 | BIGNUM *gcd = BN_CTX_get(ctx); |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 956 | BIGNUM *sqrt2 = BN_CTX_get(ctx); |
| 957 | if (totient == NULL || pm1 == NULL || qm1 == NULL || gcd == NULL || |
| 958 | sqrt2 == NULL) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 959 | goto bn_err; |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 960 | } |
| 961 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 962 | // We need the RSA components non-NULL. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 963 | if (!ensure_bignum(&rsa->n) || |
| 964 | !ensure_bignum(&rsa->d) || |
| 965 | !ensure_bignum(&rsa->e) || |
| 966 | !ensure_bignum(&rsa->p) || |
| 967 | !ensure_bignum(&rsa->q) || |
| 968 | !ensure_bignum(&rsa->dmp1) || |
| 969 | !ensure_bignum(&rsa->dmq1) || |
| 970 | !ensure_bignum(&rsa->iqmp)) { |
| 971 | goto bn_err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 972 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 973 | |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 974 | if (!BN_copy(rsa->e, e_value)) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 975 | goto bn_err; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 976 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 977 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 978 | int prime_bits = bits / 2; |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 979 | |
| 980 | // Compute sqrt2 >= ⌊2^(prime_bits-1)×√2⌋. |
| 981 | if (!bn_set_words(sqrt2, kBoringSSLRSASqrtTwo, kBoringSSLRSASqrtTwoLen)) { |
| 982 | goto bn_err; |
| 983 | } |
| 984 | int sqrt2_bits = kBoringSSLRSASqrtTwoLen * BN_BITS2; |
| 985 | assert(sqrt2_bits == (int)BN_num_bits(sqrt2)); |
| 986 | if (sqrt2_bits > prime_bits) { |
| 987 | // For key sizes up to 3072 (prime_bits = 1536), this is exactly |
| 988 | // ⌊2^(prime_bits-1)×√2⌋. |
| 989 | if (!BN_rshift(sqrt2, sqrt2, sqrt2_bits - prime_bits)) { |
| 990 | goto bn_err; |
| 991 | } |
| 992 | } else if (prime_bits > sqrt2_bits) { |
| 993 | // For key sizes beyond 3072, this is approximate. We err towards retrying |
| 994 | // to ensure our key is the right size and round up. |
| 995 | if (!BN_add_word(sqrt2, 1) || |
| 996 | !BN_lshift(sqrt2, sqrt2, prime_bits - sqrt2_bits)) { |
| 997 | goto bn_err; |
| 998 | } |
| 999 | } |
| 1000 | assert(prime_bits == (int)BN_num_bits(sqrt2)); |
| 1001 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1002 | do { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1003 | // Generate p and q, each of size |prime_bits|, using the steps outlined in |
| 1004 | // appendix FIPS 186-4 appendix B.3.3. |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 1005 | if (!generate_prime(rsa->p, prime_bits, rsa->e, NULL, sqrt2, ctx, cb) || |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1006 | !BN_GENCB_call(cb, 3, 0) || |
Robert Sloan | 8542c08 | 2018-02-05 09:07:34 -0800 | [diff] [blame] | 1007 | !generate_prime(rsa->q, prime_bits, rsa->e, rsa->p, sqrt2, ctx, cb) || |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1008 | !BN_GENCB_call(cb, 3, 1)) { |
| 1009 | goto bn_err; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1010 | } |
| 1011 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1012 | if (BN_cmp(rsa->p, rsa->q) < 0) { |
| 1013 | BIGNUM *tmp = rsa->p; |
| 1014 | rsa->p = rsa->q; |
| 1015 | rsa->q = tmp; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1016 | } |
| 1017 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1018 | // Calculate d = e^(-1) (mod lcm(p-1, q-1)), per FIPS 186-4. This differs |
| 1019 | // from typical RSA implementations which use (p-1)*(q-1). |
| 1020 | // |
| 1021 | // Note this means the size of d might reveal information about p-1 and |
| 1022 | // q-1. However, we do operations with Chinese Remainder Theorem, so we only |
| 1023 | // use d (mod p-1) and d (mod q-1) as exponents. Using a minimal totient |
| 1024 | // does not affect those two values. |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1025 | if (!BN_sub(pm1, rsa->p, BN_value_one()) || |
| 1026 | !BN_sub(qm1, rsa->q, BN_value_one()) || |
| 1027 | !BN_mul(totient, pm1, qm1, ctx) || |
| 1028 | !BN_gcd(gcd, pm1, qm1, ctx) || |
| 1029 | !BN_div(totient, NULL, totient, gcd, ctx) || |
| 1030 | !BN_mod_inverse(rsa->d, rsa->e, totient, ctx)) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1031 | goto bn_err; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1032 | } |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1033 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1034 | // Check that |rsa->d| > 2^|prime_bits| and try again if it fails. See |
| 1035 | // appendix B.3.1's guidance on values for d. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1036 | } while (!rsa_greater_than_pow2(rsa->d, prime_bits)); |
| 1037 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1038 | if (// Calculate n. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1039 | !BN_mul(rsa->n, rsa->p, rsa->q, ctx) || |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1040 | // Calculate d mod (p-1). |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1041 | !BN_mod(rsa->dmp1, rsa->d, pm1, ctx) || |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1042 | // Calculate d mod (q-1) |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1043 | !BN_mod(rsa->dmq1, rsa->d, qm1, ctx)) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1044 | goto bn_err; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1045 | } |
| 1046 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1047 | // Sanity-check that |rsa->n| has the specified size. This is implied by |
| 1048 | // |generate_prime|'s bounds. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1049 | if (BN_num_bits(rsa->n) != (unsigned)bits) { |
| 1050 | OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1051 | goto err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 1052 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1053 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1054 | // Calculate inverse of q mod p. Note that although RSA key generation is far |
| 1055 | // from constant-time, |bn_mod_inverse_secret_prime| uses the same modular |
| 1056 | // exponentation logic as in RSA private key operations and, if the RSAZ-1024 |
| 1057 | // code is enabled, will be optimized for common RSA prime sizes. |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 1058 | if (!BN_MONT_CTX_set_locked(&rsa->mont_p, &rsa->lock, rsa->p, ctx) || |
Steven Valdez | b0b45c6 | 2017-01-17 16:23:54 -0500 | [diff] [blame] | 1059 | !bn_mod_inverse_secret_prime(rsa->iqmp, rsa->q, rsa->p, ctx, |
| 1060 | rsa->mont_p)) { |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1061 | goto bn_err; |
Adam Langley | e9ada86 | 2015-05-11 17:20:37 -0700 | [diff] [blame] | 1062 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1063 | |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1064 | // The key generation process is complex and thus error-prone. It could be |
| 1065 | // disastrous to generate and then use a bad key so double-check that the key |
| 1066 | // makes sense. |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1067 | if (!RSA_check_key(rsa)) { |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 1068 | OPENSSL_PUT_ERROR(RSA, RSA_R_INTERNAL_ERROR); |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1069 | goto err; |
Robert Sloan | 69939df | 2017-01-09 10:53:07 -0800 | [diff] [blame] | 1070 | } |
| 1071 | |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1072 | ret = 1; |
| 1073 | |
| 1074 | bn_err: |
| 1075 | if (!ret) { |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1076 | OPENSSL_PUT_ERROR(RSA, ERR_LIB_BN); |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1077 | } |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1078 | err: |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1079 | if (ctx != NULL) { |
| 1080 | BN_CTX_end(ctx); |
| 1081 | BN_CTX_free(ctx); |
| 1082 | } |
Robert Sloan | 572a4e2 | 2017-04-17 10:52:19 -0700 | [diff] [blame] | 1083 | return ret; |
Kenny Root | b849459 | 2015-09-25 02:29:14 +0000 | [diff] [blame] | 1084 | } |
| 1085 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1086 | int RSA_generate_key_fips(RSA *rsa, int bits, BN_GENCB *cb) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1087 | // FIPS 186-4 allows 2048-bit and 3072-bit RSA keys (1024-bit and 1536-bit |
| 1088 | // primes, respectively) with the prime generation method we use. |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1089 | if (bits != 2048 && bits != 3072) { |
| 1090 | OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_RSA_PARAMETERS); |
| 1091 | return 0; |
| 1092 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1093 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1094 | BIGNUM *e = BN_new(); |
| 1095 | int ret = e != NULL && |
| 1096 | BN_set_word(e, RSA_F4) && |
| 1097 | RSA_generate_key_ex(rsa, bits, e, cb) && |
| 1098 | RSA_check_fips(rsa); |
| 1099 | BN_free(e); |
| 1100 | return ret; |
| 1101 | } |
Adam Langley | d9e397b | 2015-01-22 14:27:53 -0800 | [diff] [blame] | 1102 | |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1103 | DEFINE_METHOD_FUNCTION(RSA_METHOD, RSA_default_method) { |
Robert Sloan | 8f860b1 | 2017-08-28 07:37:06 -0700 | [diff] [blame] | 1104 | // All of the methods are NULL to make it easier for the compiler/linker to |
| 1105 | // drop unused functions. The wrapper functions will select the appropriate |
| 1106 | // |rsa_default_*| implementation. |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1107 | OPENSSL_memset(out, 0, sizeof(RSA_METHOD)); |
| 1108 | out->common.is_static = 1; |
Robert Sloan | 8ff0355 | 2017-06-14 12:40:58 -0700 | [diff] [blame] | 1109 | } |