| /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL |
| * project 2005. |
| */ |
| /* ==================================================================== |
| * Copyright (c) 2005 The OpenSSL Project. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. All advertising materials mentioning features or use of this |
| * software must display the following acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" |
| * |
| * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For written permission, please contact |
| * licensing@OpenSSL.org. |
| * |
| * 5. Products derived from this software may not be called "OpenSSL" |
| * nor may "OpenSSL" appear in their names without prior written |
| * permission of the OpenSSL Project. |
| * |
| * 6. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This product includes cryptographic software written by Eric Young |
| * (eay@cryptsoft.com). This product includes software written by Tim |
| * Hudson (tjh@cryptsoft.com). */ |
| |
| #include <openssl/rsa.h> |
| |
| #include <assert.h> |
| #include <limits.h> |
| #include <string.h> |
| |
| #include <openssl/digest.h> |
| #include <openssl/err.h> |
| #include <openssl/mem.h> |
| #include <openssl/rand.h> |
| #include <openssl/sha.h> |
| |
| #include "internal.h" |
| #include "../internal.h" |
| |
| /* TODO(fork): don't the check functions have to be constant time? */ |
| |
| int RSA_padding_add_PKCS1_type_1(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen) { |
| unsigned j; |
| uint8_t *p; |
| |
| if (tlen < RSA_PKCS1_PADDING_SIZE) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| return 0; |
| } |
| |
| if (flen > tlen - RSA_PKCS1_PADDING_SIZE) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| return 0; |
| } |
| |
| p = (uint8_t *)to; |
| |
| *(p++) = 0; |
| *(p++) = 1; /* Private Key BT (Block Type) */ |
| |
| /* pad out with 0xff data */ |
| j = tlen - 3 - flen; |
| memset(p, 0xff, j); |
| p += j; |
| *(p++) = 0; |
| memcpy(p, from, (unsigned int)flen); |
| return 1; |
| } |
| |
| int RSA_padding_check_PKCS1_type_1(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen) { |
| unsigned i, j; |
| const uint8_t *p; |
| |
| if (flen < 2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_SMALL); |
| return -1; |
| } |
| |
| p = from; |
| if ((*(p++) != 0) || (*(p++) != 1)) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_BLOCK_TYPE_IS_NOT_01); |
| return -1; |
| } |
| |
| /* scan over padding data */ |
| j = flen - 2; /* one for leading 00, one for type. */ |
| for (i = 0; i < j; i++) { |
| /* should decrypt to 0xff */ |
| if (*p != 0xff) { |
| if (*p == 0) { |
| p++; |
| break; |
| } else { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_FIXED_HEADER_DECRYPT); |
| return -1; |
| } |
| } |
| p++; |
| } |
| |
| if (i == j) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_NULL_BEFORE_BLOCK_MISSING); |
| return -1; |
| } |
| |
| if (i < 8) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_PAD_BYTE_COUNT); |
| return -1; |
| } |
| i++; /* Skip over the '\0' */ |
| j -= i; |
| if (j > tlen) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
| return -1; |
| } |
| memcpy(to, p, j); |
| |
| return j; |
| } |
| |
| int RSA_padding_add_PKCS1_type_2(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen) { |
| unsigned i, j; |
| uint8_t *p; |
| |
| if (tlen < RSA_PKCS1_PADDING_SIZE) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| return 0; |
| } |
| |
| if (flen > tlen - RSA_PKCS1_PADDING_SIZE) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| return 0; |
| } |
| |
| p = (unsigned char *)to; |
| |
| *(p++) = 0; |
| *(p++) = 2; /* Public Key BT (Block Type) */ |
| |
| /* pad out with non-zero random data */ |
| j = tlen - 3 - flen; |
| |
| if (!RAND_bytes(p, j)) { |
| return 0; |
| } |
| |
| for (i = 0; i < j; i++) { |
| while (*p == 0) { |
| if (!RAND_bytes(p, 1)) { |
| return 0; |
| } |
| } |
| p++; |
| } |
| |
| *(p++) = 0; |
| |
| memcpy(p, from, (unsigned int)flen); |
| return 1; |
| } |
| |
| int RSA_message_index_PKCS1_type_2(const uint8_t *from, size_t from_len, |
| size_t *out_index) { |
| size_t i; |
| unsigned first_byte_is_zero, second_byte_is_two, looking_for_index; |
| unsigned valid_index, zero_index = 0; |
| |
| /* PKCS#1 v1.5 decryption. See "PKCS #1 v2.2: RSA Cryptography |
| * Standard", section 7.2.2. */ |
| if (from_len < RSA_PKCS1_PADDING_SIZE || from_len > UINT_MAX) { |
| /* |from| is zero-padded to the size of the RSA modulus, a public value, so |
| * this can be rejected in non-constant time. This logic also requires |
| * |from_len| fit in an |unsigned|. */ |
| *out_index = 0; |
| return 0; |
| } |
| |
| first_byte_is_zero = constant_time_eq(from[0], 0); |
| second_byte_is_two = constant_time_eq(from[1], 2); |
| |
| looking_for_index = ~0u; |
| for (i = 2; i < from_len; i++) { |
| unsigned equals0 = constant_time_is_zero(from[i]); |
| zero_index = constant_time_select(looking_for_index & equals0, (unsigned)i, |
| zero_index); |
| looking_for_index = constant_time_select(equals0, 0, looking_for_index); |
| } |
| |
| /* The input must begin with 00 02. */ |
| valid_index = first_byte_is_zero; |
| valid_index &= second_byte_is_two; |
| |
| /* We must have found the end of PS. */ |
| valid_index &= ~looking_for_index; |
| |
| /* PS must be at least 8 bytes long, and it starts two bytes into |from|. */ |
| valid_index &= constant_time_ge(zero_index, 2 + 8); |
| |
| /* Skip the zero byte. */ |
| zero_index++; |
| |
| *out_index = constant_time_select(valid_index, zero_index, 0); |
| return constant_time_select(valid_index, 1, 0); |
| } |
| |
| int RSA_padding_check_PKCS1_type_2(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen) { |
| size_t msg_index, msg_len; |
| |
| if (flen == 0) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_EMPTY_PUBLIC_KEY); |
| return -1; |
| } |
| |
| /* NOTE: Although |RSA_message_index_PKCS1_type_2| itself is constant time, |
| * the API contracts of this function and |RSA_decrypt| with |
| * |RSA_PKCS1_PADDING| make it impossible to completely avoid Bleichenbacher's |
| * attack. */ |
| if (!RSA_message_index_PKCS1_type_2(from, flen, &msg_index)) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_PKCS_DECODING_ERROR); |
| return -1; |
| } |
| |
| msg_len = flen - msg_index; |
| if (msg_len > tlen) { |
| /* This shouldn't happen because this function is always called with |tlen| |
| * the key size and |flen| is bounded by the key size. */ |
| OPENSSL_PUT_ERROR(RSA, RSA_R_PKCS_DECODING_ERROR); |
| return -1; |
| } |
| memcpy(to, &from[msg_index], msg_len); |
| return msg_len; |
| } |
| |
| int RSA_padding_add_none(uint8_t *to, unsigned tlen, const uint8_t *from, unsigned flen) { |
| if (flen > tlen) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| return 0; |
| } |
| |
| if (flen < tlen) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE); |
| return 0; |
| } |
| |
| memcpy(to, from, (unsigned int)flen); |
| return 1; |
| } |
| |
| int PKCS1_MGF1(uint8_t *mask, unsigned len, const uint8_t *seed, |
| unsigned seedlen, const EVP_MD *dgst) { |
| unsigned outlen = 0; |
| uint32_t i; |
| uint8_t cnt[4]; |
| EVP_MD_CTX c; |
| uint8_t md[EVP_MAX_MD_SIZE]; |
| unsigned mdlen; |
| int ret = -1; |
| |
| EVP_MD_CTX_init(&c); |
| mdlen = EVP_MD_size(dgst); |
| |
| for (i = 0; outlen < len; i++) { |
| cnt[0] = (uint8_t)((i >> 24) & 255); |
| cnt[1] = (uint8_t)((i >> 16) & 255); |
| cnt[2] = (uint8_t)((i >> 8)) & 255; |
| cnt[3] = (uint8_t)(i & 255); |
| if (!EVP_DigestInit_ex(&c, dgst, NULL) || |
| !EVP_DigestUpdate(&c, seed, seedlen) || !EVP_DigestUpdate(&c, cnt, 4)) { |
| goto err; |
| } |
| |
| if (outlen + mdlen <= len) { |
| if (!EVP_DigestFinal_ex(&c, mask + outlen, NULL)) { |
| goto err; |
| } |
| outlen += mdlen; |
| } else { |
| if (!EVP_DigestFinal_ex(&c, md, NULL)) { |
| goto err; |
| } |
| memcpy(mask + outlen, md, len - outlen); |
| outlen = len; |
| } |
| } |
| ret = 0; |
| |
| err: |
| EVP_MD_CTX_cleanup(&c); |
| return ret; |
| } |
| |
| int RSA_padding_add_PKCS1_OAEP_mgf1(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen, |
| const uint8_t *param, unsigned plen, |
| const EVP_MD *md, const EVP_MD *mgf1md) { |
| unsigned i, emlen, mdlen; |
| uint8_t *db, *seed; |
| uint8_t *dbmask = NULL, seedmask[EVP_MAX_MD_SIZE]; |
| int ret = 0; |
| |
| if (md == NULL) { |
| md = EVP_sha1(); |
| } |
| if (mgf1md == NULL) { |
| mgf1md = md; |
| } |
| |
| mdlen = EVP_MD_size(md); |
| |
| if (tlen < 2 * mdlen + 2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| return 0; |
| } |
| |
| emlen = tlen - 1; |
| if (flen > emlen - 2 * mdlen - 1) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| return 0; |
| } |
| |
| if (emlen < 2 * mdlen + 1) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_KEY_SIZE_TOO_SMALL); |
| return 0; |
| } |
| |
| to[0] = 0; |
| seed = to + 1; |
| db = to + mdlen + 1; |
| |
| if (!EVP_Digest((void *)param, plen, db, NULL, md, NULL)) { |
| return 0; |
| } |
| memset(db + mdlen, 0, emlen - flen - 2 * mdlen - 1); |
| db[emlen - flen - mdlen - 1] = 0x01; |
| memcpy(db + emlen - flen - mdlen, from, flen); |
| if (!RAND_bytes(seed, mdlen)) { |
| return 0; |
| } |
| |
| dbmask = OPENSSL_malloc(emlen - mdlen); |
| if (dbmask == NULL) { |
| OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| return 0; |
| } |
| |
| if (PKCS1_MGF1(dbmask, emlen - mdlen, seed, mdlen, mgf1md) < 0) { |
| goto out; |
| } |
| for (i = 0; i < emlen - mdlen; i++) { |
| db[i] ^= dbmask[i]; |
| } |
| |
| if (PKCS1_MGF1(seedmask, mdlen, db, emlen - mdlen, mgf1md) < 0) { |
| goto out; |
| } |
| for (i = 0; i < mdlen; i++) { |
| seed[i] ^= seedmask[i]; |
| } |
| ret = 1; |
| |
| out: |
| OPENSSL_free(dbmask); |
| return ret; |
| } |
| |
| int RSA_padding_check_PKCS1_OAEP_mgf1(uint8_t *to, unsigned tlen, |
| const uint8_t *from, unsigned flen, |
| const uint8_t *param, unsigned plen, |
| const EVP_MD *md, const EVP_MD *mgf1md) { |
| unsigned i, dblen, mlen = -1, mdlen, bad, looking_for_one_byte, one_index = 0; |
| const uint8_t *maskeddb, *maskedseed; |
| uint8_t *db = NULL, seed[EVP_MAX_MD_SIZE], phash[EVP_MAX_MD_SIZE]; |
| |
| if (md == NULL) { |
| md = EVP_sha1(); |
| } |
| if (mgf1md == NULL) { |
| mgf1md = md; |
| } |
| |
| mdlen = EVP_MD_size(md); |
| |
| /* The encoded message is one byte smaller than the modulus to ensure that it |
| * doesn't end up greater than the modulus. Thus there's an extra "+1" here |
| * compared to https://tools.ietf.org/html/rfc2437#section-9.1.1.2. */ |
| if (flen < 1 + 2*mdlen + 1) { |
| /* 'flen' is the length of the modulus, i.e. does not depend on the |
| * particular ciphertext. */ |
| goto decoding_err; |
| } |
| |
| dblen = flen - mdlen - 1; |
| db = OPENSSL_malloc(dblen); |
| if (db == NULL) { |
| OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| |
| maskedseed = from + 1; |
| maskeddb = from + 1 + mdlen; |
| |
| if (PKCS1_MGF1(seed, mdlen, maskeddb, dblen, mgf1md)) { |
| goto err; |
| } |
| for (i = 0; i < mdlen; i++) { |
| seed[i] ^= maskedseed[i]; |
| } |
| |
| if (PKCS1_MGF1(db, dblen, seed, mdlen, mgf1md)) { |
| goto err; |
| } |
| for (i = 0; i < dblen; i++) { |
| db[i] ^= maskeddb[i]; |
| } |
| |
| if (!EVP_Digest((void *)param, plen, phash, NULL, md, NULL)) { |
| goto err; |
| } |
| |
| bad = ~constant_time_is_zero(CRYPTO_memcmp(db, phash, mdlen)); |
| bad |= ~constant_time_is_zero(from[0]); |
| |
| looking_for_one_byte = ~0u; |
| for (i = mdlen; i < dblen; i++) { |
| unsigned equals1 = constant_time_eq(db[i], 1); |
| unsigned equals0 = constant_time_eq(db[i], 0); |
| one_index = constant_time_select(looking_for_one_byte & equals1, i, one_index); |
| looking_for_one_byte = |
| constant_time_select(equals1, 0, looking_for_one_byte); |
| bad |= looking_for_one_byte & ~equals0; |
| } |
| |
| bad |= looking_for_one_byte; |
| |
| if (bad) { |
| goto decoding_err; |
| } |
| |
| one_index++; |
| mlen = dblen - one_index; |
| if (tlen < mlen) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
| mlen = -1; |
| } else { |
| memcpy(to, db + one_index, mlen); |
| } |
| |
| OPENSSL_free(db); |
| return mlen; |
| |
| decoding_err: |
| /* to avoid chosen ciphertext attacks, the error message should not reveal |
| * which kind of decoding error happened */ |
| OPENSSL_PUT_ERROR(RSA, RSA_R_OAEP_DECODING_ERROR); |
| err: |
| OPENSSL_free(db); |
| return -1; |
| } |
| |
| static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0}; |
| |
| int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const uint8_t *mHash, |
| const EVP_MD *Hash, const EVP_MD *mgf1Hash, |
| const uint8_t *EM, int sLen) { |
| int i; |
| int ret = 0; |
| int maskedDBLen, MSBits, emLen; |
| size_t hLen; |
| const uint8_t *H; |
| uint8_t *DB = NULL; |
| EVP_MD_CTX ctx; |
| uint8_t H_[EVP_MAX_MD_SIZE]; |
| EVP_MD_CTX_init(&ctx); |
| |
| if (mgf1Hash == NULL) { |
| mgf1Hash = Hash; |
| } |
| |
| hLen = EVP_MD_size(Hash); |
| |
| /* Negative sLen has special meanings: |
| * -1 sLen == hLen |
| * -2 salt length is autorecovered from signature |
| * -N reserved */ |
| if (sLen == -1) { |
| sLen = hLen; |
| } else if (sLen == -2) { |
| sLen = -2; |
| } else if (sLen < -2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_CHECK_FAILED); |
| goto err; |
| } |
| |
| MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; |
| emLen = RSA_size(rsa); |
| if (EM[0] & (0xFF << MSBits)) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_FIRST_OCTET_INVALID); |
| goto err; |
| } |
| if (MSBits == 0) { |
| EM++; |
| emLen--; |
| } |
| if (emLen < ((int)hLen + sLen + 2)) { |
| /* sLen can be small negative */ |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE); |
| goto err; |
| } |
| if (EM[emLen - 1] != 0xbc) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_LAST_OCTET_INVALID); |
| goto err; |
| } |
| maskedDBLen = emLen - hLen - 1; |
| H = EM + maskedDBLen; |
| DB = OPENSSL_malloc(maskedDBLen); |
| if (!DB) { |
| OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0) { |
| goto err; |
| } |
| for (i = 0; i < maskedDBLen; i++) { |
| DB[i] ^= EM[i]; |
| } |
| if (MSBits) { |
| DB[0] &= 0xFF >> (8 - MSBits); |
| } |
| for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) { |
| ; |
| } |
| if (DB[i++] != 0x1) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_RECOVERY_FAILED); |
| goto err; |
| } |
| if (sLen >= 0 && (maskedDBLen - i) != sLen) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_CHECK_FAILED); |
| goto err; |
| } |
| if (!EVP_DigestInit_ex(&ctx, Hash, NULL) || |
| !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) || |
| !EVP_DigestUpdate(&ctx, mHash, hLen)) { |
| goto err; |
| } |
| if (maskedDBLen - i) { |
| if (!EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i)) { |
| goto err; |
| } |
| } |
| if (!EVP_DigestFinal_ex(&ctx, H_, NULL)) { |
| goto err; |
| } |
| if (memcmp(H_, H, hLen)) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_BAD_SIGNATURE); |
| ret = 0; |
| } else { |
| ret = 1; |
| } |
| |
| err: |
| OPENSSL_free(DB); |
| EVP_MD_CTX_cleanup(&ctx); |
| |
| return ret; |
| } |
| |
| int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM, |
| const unsigned char *mHash, |
| const EVP_MD *Hash, const EVP_MD *mgf1Hash, |
| int sLen) { |
| int i; |
| int ret = 0; |
| size_t maskedDBLen, MSBits, emLen; |
| size_t hLen; |
| unsigned char *H, *salt = NULL, *p; |
| EVP_MD_CTX ctx; |
| |
| if (mgf1Hash == NULL) { |
| mgf1Hash = Hash; |
| } |
| |
| hLen = EVP_MD_size(Hash); |
| |
| /* Negative sLen has special meanings: |
| * -1 sLen == hLen |
| * -2 salt length is maximized |
| * -N reserved */ |
| if (sLen == -1) { |
| sLen = hLen; |
| } else if (sLen == -2) { |
| sLen = -2; |
| } else if (sLen < -2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_SLEN_CHECK_FAILED); |
| goto err; |
| } |
| |
| if (BN_is_zero(rsa->n)) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_EMPTY_PUBLIC_KEY); |
| goto err; |
| } |
| |
| MSBits = (BN_num_bits(rsa->n) - 1) & 0x7; |
| emLen = RSA_size(rsa); |
| if (MSBits == 0) { |
| assert(emLen >= 1); |
| *EM++ = 0; |
| emLen--; |
| } |
| if (sLen == -2) { |
| if (emLen < hLen + 2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| goto err; |
| } |
| sLen = emLen - hLen - 2; |
| } else if (emLen < hLen + sLen + 2) { |
| OPENSSL_PUT_ERROR(RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE); |
| goto err; |
| } |
| if (sLen > 0) { |
| salt = OPENSSL_malloc(sLen); |
| if (!salt) { |
| OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE); |
| goto err; |
| } |
| if (!RAND_bytes(salt, sLen)) { |
| goto err; |
| } |
| } |
| maskedDBLen = emLen - hLen - 1; |
| H = EM + maskedDBLen; |
| EVP_MD_CTX_init(&ctx); |
| if (!EVP_DigestInit_ex(&ctx, Hash, NULL) || |
| !EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes) || |
| !EVP_DigestUpdate(&ctx, mHash, hLen)) { |
| goto err; |
| } |
| if (sLen && !EVP_DigestUpdate(&ctx, salt, sLen)) { |
| goto err; |
| } |
| if (!EVP_DigestFinal_ex(&ctx, H, NULL)) { |
| goto err; |
| } |
| EVP_MD_CTX_cleanup(&ctx); |
| |
| /* Generate dbMask in place then perform XOR on it */ |
| if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash)) { |
| goto err; |
| } |
| |
| p = EM; |
| |
| /* Initial PS XORs with all zeroes which is a NOP so just update |
| * pointer. Note from a test above this value is guaranteed to |
| * be non-negative. */ |
| p += emLen - sLen - hLen - 2; |
| *p++ ^= 0x1; |
| if (sLen > 0) { |
| for (i = 0; i < sLen; i++) { |
| *p++ ^= salt[i]; |
| } |
| } |
| if (MSBits) { |
| EM[0] &= 0xFF >> (8 - MSBits); |
| } |
| |
| /* H is already in place so just set final 0xbc */ |
| |
| EM[emLen - 1] = 0xbc; |
| |
| ret = 1; |
| |
| err: |
| OPENSSL_free(salt); |
| |
| return ret; |
| } |