-/* crypto/rsa/rsa_pk1.c */
-/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
+/*
+ * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
*
- * This package is an SSL implementation written
- * by Eric Young (eay@cryptsoft.com).
- * The implementation was written so as to conform with Netscapes SSL.
- *
- * This library is free for commercial and non-commercial use as long as
- * the following conditions are aheared to. The following conditions
- * apply to all code found in this distribution, be it the RC4, RSA,
- * lhash, DES, etc., code; not just the SSL code. The SSL documentation
- * included with this distribution is covered by the same copyright terms
- * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
- * Copyright remains Eric Young's, and as such any Copyright notices in
- * the code are not to be removed.
- * If this package is used in a product, Eric Young should be given attribution
- * as the author of the parts of the library used.
- * This can be in the form of a textual message at program startup or
- * in documentation (online or textual) provided with the package.
- *
- * 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 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 acknowledgement:
- * "This product includes cryptographic software written by
- * Eric Young (eay@cryptsoft.com)"
- * The word 'cryptographic' can be left out if the rouines from the library
- * being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
- * the apps directory (application code) you must include an acknowledgement:
- * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
- * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
- * ANY EXPRESS 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 AUTHOR OR 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.
- *
- * The licence and distribution terms for any publically available version or
- * derivative of this code cannot be changed. i.e. this code cannot simply be
- * copied and put under another distribution licence
- * [including the GNU Public Licence.]
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*/
+#include "internal/constant_time_locl.h"
+
#include <stdio.h>
-#include "cryptlib.h"
-#include "bn.h"
-#include "rsa.h"
-#include "rand.h"
-
-#ifndef NOPROTO
-int RSA_padding_add_PKCS1_type_1();
-int RSA_padding_check_PKCS1_type_1();
-int RSA_padding_add_PKCS1_type_2();
-int RSA_padding_check_PKCS1_type_2();
-int RSA_padding_add_SSLv23();
-int RSA_padding_check_SSLv23();
-int RSA_padding_add_none();
-int RSA_padding_check_none();
-
-#endif
+#include "internal/cryptlib.h"
+#include <openssl/bn.h>
+#include <openssl/rsa.h>
+#include <openssl/rand.h>
int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
- unsigned char *from, int flen)
- {
- int j;
- unsigned char *p;
-
- if (flen > (tlen-11))
- {
- RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_1,RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
- return(0);
- }
-
- p=(unsigned char *)to;
-
- *(p++)=0;
- *(p++)=1; /* Private Key BT (Block Type) */
-
- /* padd out with 0xff data */
- j=tlen-3-flen;
- memset(p,0xff,j);
- p+=j;
- *(p++)='\0';
- memcpy(p,from,(unsigned int)flen);
- return(1);
- }
+ const unsigned char *from, int flen)
+{
+ int j;
+ unsigned char *p;
+
+ if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {
+ RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_1,
+ RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
+ return 0;
+ }
+
+ p = (unsigned char *)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(unsigned char *to, int tlen,
- unsigned char *from, int flen, int num)
- {
- int i,j;
- unsigned char *p;
-
- p=from;
- if ((num != (flen+1)) || (*(p++) != 01))
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BLOCK_TYPE_IS_NOT_01);
- return(-1);
- }
-
- /* scan over padding data */
- j=flen-1; /* one for type. */
- for (i=0; i<j; i++)
- {
- if (*p != 0xff) /* should decrypt to 0xff */
- {
- if (*p == 0)
- { p++; break; }
- else {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_FIXED_HEADER_DECRYPT);
- return(-1);
- }
- }
- p++;
- }
-
- if (i == j)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_NULL_BEFORE_BLOCK_MISSING);
- return(-1);
- }
-
- if (i < 8)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,RSA_R_BAD_PAD_BYTE_COUNT);
- return(-1);
- }
- i++; /* Skip over the '\0' */
- j-=i;
- memcpy(to,p,(unsigned int)j);
-
- return(j);
- }
+ const unsigned char *from, int flen,
+ int num)
+{
+ int i, j;
+ const unsigned char *p;
+
+ p = from;
+
+ /*
+ * The format is
+ * 00 || 01 || PS || 00 || D
+ * PS - padding string, at least 8 bytes of FF
+ * D - data.
+ */
+
+ if (num < 11)
+ return -1;
+
+ /* Accept inputs with and without the leading 0-byte. */
+ if (num == flen) {
+ if ((*p++) != 0x00) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,
+ RSA_R_INVALID_PADDING);
+ return -1;
+ }
+ flen--;
+ }
+
+ if ((num != (flen + 1)) || (*(p++) != 0x01)) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,
+ RSA_R_BLOCK_TYPE_IS_NOT_01);
+ return -1;
+ }
+
+ /* scan over padding data */
+ j = flen - 1; /* one for type. */
+ for (i = 0; i < j; i++) {
+ if (*p != 0xff) { /* should decrypt to 0xff */
+ if (*p == 0) {
+ p++;
+ break;
+ } else {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,
+ RSA_R_BAD_FIXED_HEADER_DECRYPT);
+ return -1;
+ }
+ }
+ p++;
+ }
+
+ if (i == j) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,
+ RSA_R_NULL_BEFORE_BLOCK_MISSING);
+ return -1;
+ }
+
+ if (i < 8) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1,
+ RSA_R_BAD_PAD_BYTE_COUNT);
+ return -1;
+ }
+ i++; /* Skip over the '\0' */
+ j -= i;
+ if (j > tlen) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_1, RSA_R_DATA_TOO_LARGE);
+ return -1;
+ }
+ memcpy(to, p, (unsigned int)j);
+
+ return j;
+}
int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
- unsigned char *from, int flen)
- {
- int i,j;
- unsigned char *p;
-
- if (flen > (tlen-11))
- {
- RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_2,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;
-
- RAND_bytes(p,j);
- for (i=0; i<j; i++)
- {
- if (*p == '\0')
- do {
- RAND_bytes(p,1);
- } while (*p == '\0');
- p++;
- }
-
- *(p++)='\0';
-
- memcpy(p,from,(unsigned int)flen);
- return(1);
- }
+ const unsigned char *from, int flen)
+{
+ int i, j;
+ unsigned char *p;
+
+ if (flen > (tlen - 11)) {
+ RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_TYPE_2,
+ 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) <= 0)
+ return 0;
+ for (i = 0; i < j; i++) {
+ if (*p == '\0')
+ do {
+ if (RAND_bytes(p, 1) <= 0)
+ return 0;
+ } while (*p == '\0');
+ p++;
+ }
+
+ *(p++) = '\0';
+
+ memcpy(p, from, (unsigned int)flen);
+ return 1;
+}
int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
- unsigned char *from, int flen, int num)
- {
- int i,j;
- unsigned char *p;
-
- p=from;
- if ((num != (flen+1)) || (*(p++) != 02))
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_BLOCK_TYPE_IS_NOT_02);
- return(-1);
- }
-#ifdef PKCS1_CHECK
- return(num-11);
-#endif
-
- /* scan over padding data */
- j=flen-1; /* one for type. */
- for (i=0; i<j; i++)
- if (*(p++) == 0) break;
-
- if (i == j)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_NULL_BEFORE_BLOCK_MISSING);
- return(-1);
- }
-
- if (i < 8)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,RSA_R_BAD_PAD_BYTE_COUNT);
- return(-1);
- }
- i++; /* Skip over the '\0' */
- j-=i;
- memcpy(to,p,(unsigned int)j);
-
- return(j);
- }
-
+ const unsigned char *from, int flen,
+ int num)
+{
+ int i;
+ /* |em| is the encoded message, zero-padded to exactly |num| bytes */
+ unsigned char *em = NULL;
+ unsigned int good, found_zero_byte;
+ int zero_index = 0, msg_index, mlen = -1;
+
+ if (tlen < 0 || flen < 0)
+ return -1;
+
+ /*
+ * PKCS#1 v1.5 decryption. See "PKCS #1 v2.2: RSA Cryptography Standard",
+ * section 7.2.2.
+ */
+
+ if (flen > num)
+ goto err;
+
+ if (num < 11)
+ goto err;
+
+ em = OPENSSL_zalloc(num);
+ if (em == NULL) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2, ERR_R_MALLOC_FAILURE);
+ return -1;
+ }
+ /*
+ * Always do this zero-padding copy (even when num == flen) to avoid
+ * leaking that information. The copy still leaks some side-channel
+ * information, but it's impossible to have a fixed memory access
+ * pattern since we can't read out of the bounds of |from|.
+ *
+ * TODO(emilia): Consider porting BN_bn2bin_padded from BoringSSL.
+ */
+ memcpy(em + num - flen, from, flen);
+
+ good = constant_time_is_zero(em[0]);
+ good &= constant_time_eq(em[1], 2);
+
+ found_zero_byte = 0;
+ for (i = 2; i < num; i++) {
+ unsigned int equals0 = constant_time_is_zero(em[i]);
+ zero_index =
+ constant_time_select_int(~found_zero_byte & equals0, i,
+ zero_index);
+ found_zero_byte |= equals0;
+ }
+
+ /*
+ * PS must be at least 8 bytes long, and it starts two bytes into |em|.
+ * If we never found a 0-byte, then |zero_index| is 0 and the check
+ * also fails.
+ */
+ good &= constant_time_ge((unsigned int)(zero_index), 2 + 8);
+
+ /*
+ * Skip the zero byte. This is incorrect if we never found a zero-byte
+ * but in this case we also do not copy the message out.
+ */
+ msg_index = zero_index + 1;
+ mlen = num - msg_index;
+
+ /*
+ * For good measure, do this check in constant time as well; it could
+ * leak something if |tlen| was assuming valid padding.
+ */
+ good &= constant_time_ge((unsigned int)(tlen), (unsigned int)(mlen));
+
+ /*
+ * We can't continue in constant-time because we need to copy the result
+ * and we cannot fake its length. This unavoidably leaks timing
+ * information at the API boundary.
+ */
+ if (!good) {
+ mlen = -1;
+ goto err;
+ }
+
+ memcpy(to, em + msg_index, mlen);
+
+ err:
+ OPENSSL_clear_free(em, num);
+ if (mlen == -1)
+ RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2,
+ RSA_R_PKCS_DECODING_ERROR);
+ return mlen;
+}
projects / openssl.git / blobdiff