| 1 | /*
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| 2 | * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <stdio.h>
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| 11 | #include "internal/cryptlib.h"
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| 12 | #include <openssl/bn.h>
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| 13 | #include <openssl/rsa.h>
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| 14 | #include <openssl/evp.h>
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| 15 | #include <openssl/rand.h>
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| 16 | #include <openssl/sha.h>
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| 17 | #include "rsa_local.h"
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| 18 |
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| 19 | static const unsigned char zeroes[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
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| 20 |
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| 21 | #if defined(_MSC_VER) && defined(_ARM_)
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| 22 | # pragma optimize("g", off)
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| 23 | #endif
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| 24 |
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| 25 | int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
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| 26 | const EVP_MD *Hash, const unsigned char *EM,
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| 27 | int sLen)
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| 28 | {
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| 29 | return RSA_verify_PKCS1_PSS_mgf1(rsa, mHash, Hash, NULL, EM, sLen);
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| 30 | }
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| 31 |
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| 32 | int RSA_verify_PKCS1_PSS_mgf1(RSA *rsa, const unsigned char *mHash,
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| 33 | const EVP_MD *Hash, const EVP_MD *mgf1Hash,
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| 34 | const unsigned char *EM, int sLen)
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| 35 | {
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| 36 | int i;
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| 37 | int ret = 0;
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| 38 | int hLen, maskedDBLen, MSBits, emLen;
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| 39 | const unsigned char *H;
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| 40 | unsigned char *DB = NULL;
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| 41 | EVP_MD_CTX *ctx = EVP_MD_CTX_new();
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| 42 | unsigned char H_[EVP_MAX_MD_SIZE];
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| 43 |
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| 44 | if (ctx == NULL)
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| 45 | goto err;
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| 46 |
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| 47 | if (mgf1Hash == NULL)
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| 48 | mgf1Hash = Hash;
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| 49 |
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| 50 | hLen = EVP_MD_size(Hash);
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| 51 | if (hLen < 0)
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| 52 | goto err;
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| 53 | /*-
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| 54 | * Negative sLen has special meanings:
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| 55 | * -1 sLen == hLen
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| 56 | * -2 salt length is autorecovered from signature
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| 57 | * -3 salt length is maximized
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| 58 | * -N reserved
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| 59 | */
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| 60 | if (sLen == RSA_PSS_SALTLEN_DIGEST) {
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| 61 | sLen = hLen;
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| 62 | } else if (sLen < RSA_PSS_SALTLEN_MAX) {
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| 63 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
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| 64 | goto err;
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| 65 | }
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| 66 |
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| 67 | MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
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| 68 | emLen = RSA_size(rsa);
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| 69 | if (EM[0] & (0xFF << MSBits)) {
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| 70 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_FIRST_OCTET_INVALID);
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| 71 | goto err;
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| 72 | }
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| 73 | if (MSBits == 0) {
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| 74 | EM++;
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| 75 | emLen--;
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| 76 | }
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| 77 | if (emLen < hLen + 2) {
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| 78 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
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| 79 | goto err;
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| 80 | }
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| 81 | if (sLen == RSA_PSS_SALTLEN_MAX) {
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| 82 | sLen = emLen - hLen - 2;
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| 83 | } else if (sLen > emLen - hLen - 2) { /* sLen can be small negative */
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| 84 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_DATA_TOO_LARGE);
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| 85 | goto err;
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| 86 | }
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| 87 | if (EM[emLen - 1] != 0xbc) {
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| 88 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_LAST_OCTET_INVALID);
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| 89 | goto err;
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| 90 | }
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| 91 | maskedDBLen = emLen - hLen - 1;
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| 92 | H = EM + maskedDBLen;
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| 93 | DB = OPENSSL_malloc(maskedDBLen);
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| 94 | if (DB == NULL) {
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| 95 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, ERR_R_MALLOC_FAILURE);
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| 96 | goto err;
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| 97 | }
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| 98 | if (PKCS1_MGF1(DB, maskedDBLen, H, hLen, mgf1Hash) < 0)
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| 99 | goto err;
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| 100 | for (i = 0; i < maskedDBLen; i++)
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| 101 | DB[i] ^= EM[i];
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| 102 | if (MSBits)
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| 103 | DB[0] &= 0xFF >> (8 - MSBits);
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| 104 | for (i = 0; DB[i] == 0 && i < (maskedDBLen - 1); i++) ;
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| 105 | if (DB[i++] != 0x1) {
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| 106 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_RECOVERY_FAILED);
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| 107 | goto err;
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| 108 | }
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| 109 | if (sLen != RSA_PSS_SALTLEN_AUTO && (maskedDBLen - i) != sLen) {
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| 110 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
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| 111 | goto err;
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| 112 | }
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| 113 | if (!EVP_DigestInit_ex(ctx, Hash, NULL)
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| 114 | || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
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| 115 | || !EVP_DigestUpdate(ctx, mHash, hLen))
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| 116 | goto err;
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| 117 | if (maskedDBLen - i) {
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| 118 | if (!EVP_DigestUpdate(ctx, DB + i, maskedDBLen - i))
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| 119 | goto err;
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| 120 | }
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| 121 | if (!EVP_DigestFinal_ex(ctx, H_, NULL))
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| 122 | goto err;
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| 123 | if (memcmp(H_, H, hLen)) {
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| 124 | RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS_MGF1, RSA_R_BAD_SIGNATURE);
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| 125 | ret = 0;
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| 126 | } else {
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| 127 | ret = 1;
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| 128 | }
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| 129 |
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| 130 | err:
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| 131 | OPENSSL_free(DB);
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| 132 | EVP_MD_CTX_free(ctx);
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| 133 |
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| 134 | return ret;
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| 135 |
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| 136 | }
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| 137 |
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| 138 | int RSA_padding_add_PKCS1_PSS(RSA *rsa, unsigned char *EM,
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| 139 | const unsigned char *mHash,
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| 140 | const EVP_MD *Hash, int sLen)
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| 141 | {
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| 142 | return RSA_padding_add_PKCS1_PSS_mgf1(rsa, EM, mHash, Hash, NULL, sLen);
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| 143 | }
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| 144 |
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| 145 | int RSA_padding_add_PKCS1_PSS_mgf1(RSA *rsa, unsigned char *EM,
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| 146 | const unsigned char *mHash,
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| 147 | const EVP_MD *Hash, const EVP_MD *mgf1Hash,
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| 148 | int sLen)
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| 149 | {
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| 150 | int i;
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| 151 | int ret = 0;
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| 152 | int hLen, maskedDBLen, MSBits, emLen;
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| 153 | unsigned char *H, *salt = NULL, *p;
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| 154 | EVP_MD_CTX *ctx = NULL;
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| 155 |
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| 156 | if (mgf1Hash == NULL)
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| 157 | mgf1Hash = Hash;
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| 158 |
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| 159 | hLen = EVP_MD_size(Hash);
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| 160 | if (hLen < 0)
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| 161 | goto err;
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| 162 | /*-
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| 163 | * Negative sLen has special meanings:
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| 164 | * -1 sLen == hLen
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| 165 | * -2 salt length is maximized
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| 166 | * -3 same as above (on signing)
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| 167 | * -N reserved
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| 168 | */
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| 169 | if (sLen == RSA_PSS_SALTLEN_DIGEST) {
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| 170 | sLen = hLen;
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| 171 | } else if (sLen == RSA_PSS_SALTLEN_MAX_SIGN) {
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| 172 | sLen = RSA_PSS_SALTLEN_MAX;
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| 173 | } else if (sLen < RSA_PSS_SALTLEN_MAX) {
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| 174 | RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1, RSA_R_SLEN_CHECK_FAILED);
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| 175 | goto err;
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| 176 | }
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| 177 |
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| 178 | MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
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| 179 | emLen = RSA_size(rsa);
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| 180 | if (MSBits == 0) {
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| 181 | *EM++ = 0;
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| 182 | emLen--;
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| 183 | }
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| 184 | if (emLen < hLen + 2) {
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| 185 | RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
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| 186 | RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
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| 187 | goto err;
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| 188 | }
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| 189 | if (sLen == RSA_PSS_SALTLEN_MAX) {
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| 190 | sLen = emLen - hLen - 2;
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| 191 | } else if (sLen > emLen - hLen - 2) {
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| 192 | RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
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| 193 | RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
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| 194 | goto err;
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| 195 | }
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| 196 | if (sLen > 0) {
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| 197 | salt = OPENSSL_malloc(sLen);
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| 198 | if (salt == NULL) {
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| 199 | RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS_MGF1,
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| 200 | ERR_R_MALLOC_FAILURE);
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| 201 | goto err;
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| 202 | }
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| 203 | if (RAND_bytes(salt, sLen) <= 0)
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| 204 | goto err;
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| 205 | }
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| 206 | maskedDBLen = emLen - hLen - 1;
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| 207 | H = EM + maskedDBLen;
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| 208 | ctx = EVP_MD_CTX_new();
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| 209 | if (ctx == NULL)
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| 210 | goto err;
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| 211 | if (!EVP_DigestInit_ex(ctx, Hash, NULL)
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| 212 | || !EVP_DigestUpdate(ctx, zeroes, sizeof(zeroes))
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| 213 | || !EVP_DigestUpdate(ctx, mHash, hLen))
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| 214 | goto err;
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| 215 | if (sLen && !EVP_DigestUpdate(ctx, salt, sLen))
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| 216 | goto err;
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| 217 | if (!EVP_DigestFinal_ex(ctx, H, NULL))
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| 218 | goto err;
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| 219 |
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| 220 | /* Generate dbMask in place then perform XOR on it */
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| 221 | if (PKCS1_MGF1(EM, maskedDBLen, H, hLen, mgf1Hash))
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| 222 | goto err;
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| 223 |
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| 224 | p = EM;
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| 225 |
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| 226 | /*
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| 227 | * Initial PS XORs with all zeroes which is a NOP so just update pointer.
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| 228 | * Note from a test above this value is guaranteed to be non-negative.
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| 229 | */
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| 230 | p += emLen - sLen - hLen - 2;
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| 231 | *p++ ^= 0x1;
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| 232 | if (sLen > 0) {
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| 233 | for (i = 0; i < sLen; i++)
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| 234 | *p++ ^= salt[i];
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| 235 | }
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| 236 | if (MSBits)
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| 237 | EM[0] &= 0xFF >> (8 - MSBits);
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| 238 |
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| 239 | /* H is already in place so just set final 0xbc */
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| 240 |
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| 241 | EM[emLen - 1] = 0xbc;
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| 242 |
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| 243 | ret = 1;
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| 244 |
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| 245 | err:
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| 246 | EVP_MD_CTX_free(ctx);
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| 247 | OPENSSL_clear_free(salt, (size_t)sLen); /* salt != NULL implies sLen > 0 */
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| 248 |
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| 249 | return ret;
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| 250 |
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| 251 | }
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| 252 |
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| 253 | #if defined(_MSC_VER)
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| 254 | # pragma optimize("",on)
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| 255 | #endif
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