-/* crypto/rsa/rsa_ssl.c */
-/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
+/*
+ * Copyright 1995-2020 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 Apache License 2.0 (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
*/
+/*
+ * RSA low level APIs are deprecated for public use, but still ok for
+ * internal use.
+ */
+#include "internal/deprecated.h"
+
#include <stdio.h>
-#include "cryptlib.h"
-#include "bn.h"
-#include "rsa.h"
-#include "rand.h"
-
-int RSA_padding_add_SSLv23(to,tlen,from,flen)
-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_SSLV23,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-3-8-flen;
-
- RAND_bytes(p,j);
- for (i=0; i<j; i++)
- {
- if (*p == '\0')
- do {
- RAND_bytes(p,1);
- } while (*p == '\0');
- p++;
- }
-
- memset(p,3,8);
- p+=8;
- *(p++)='\0';
-
- memcpy(p,from,(unsigned int)flen);
- return(1);
- }
-
-int RSA_padding_check_SSLv23(to,tlen,from,flen,num)
-unsigned char *to;
-int tlen;
-unsigned char *from;
-int flen;
-int num;
- {
- int i,j,k;
- unsigned char *p;
-
- p=from;
- if (flen < 10)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_DATA_TOO_SMALL);
- return(-1);
- }
- if ((num != (flen+1)) || (*(p++) != 02))
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_BLOCK_TYPE_IS_NOT_02);
- return(-1);
- }
-
- /* scan over padding data */
- j=flen-1; /* one for type */
- for (i=0; i<j; i++)
- if (*(p++) == 0) break;
-
- if ((i == j) || (i < 8))
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_NULL_BEFORE_BLOCK_MISSING);
- return(-1);
- }
- for (k= -8; k<0; k++)
- {
- if (p[k] != 0x03) break;
- }
- if (k == 0)
- {
- RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23,RSA_R_SSLV3_ROLLBACK_ATTACK);
- return(-1);
- }
-
- i++; /* Skip over the '\0' */
- j-=i;
- memcpy(to,p,(unsigned int)j);
-
- return(j);
- }
+#include "internal/cryptlib.h"
+#include <openssl/bn.h>
+#include <openssl/rsa.h>
+#include <openssl/rand.h>
+#include "internal/constant_time.h"
+#include "rsa_local.h"
+
+int ossl_rsa_padding_add_SSLv23_ex(OPENSSL_CTX *libctx, unsigned char *to,
+ int tlen, const unsigned char *from,
+ int flen)
+{
+ int i, j;
+ unsigned char *p;
+
+ if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {
+ RSAerr(0, 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 - 8 - flen;
+
+ if (RAND_bytes_ex(libctx, p, j) <= 0)
+ return 0;
+ for (i = 0; i < j; i++) {
+ if (*p == '\0')
+ do {
+ if (RAND_bytes_ex(libctx, p, 1) <= 0)
+ return 0;
+ } while (*p == '\0');
+ p++;
+ }
+
+ memset(p, 3, 8);
+ p += 8;
+ *(p++) = '\0';
+
+ memcpy(p, from, (unsigned int)flen);
+ return 1;
+}
+
+int RSA_padding_add_SSLv23(unsigned char *to, int tlen,
+ const unsigned char *from, int flen)
+{
+ return ossl_rsa_padding_add_SSLv23_ex(NULL, to, tlen, from, flen);
+}
+
+/*
+ * Copy of RSA_padding_check_PKCS1_type_2 with a twist that rejects padding
+ * if nul delimiter is not preceded by 8 consecutive 0x03 bytes. It also
+ * preserves error code reporting for backward compatibility.
+ */
+int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
+ 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, mask, threes_in_row;
+ int zero_index = 0, msg_index, mlen = -1, err;
+
+ if (tlen <= 0 || flen <= 0)
+ return -1;
+
+ if (flen > num || num < RSA_PKCS1_PADDING_SIZE) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23, RSA_R_DATA_TOO_SMALL);
+ return -1;
+ }
+
+ em = OPENSSL_malloc(num);
+ if (em == NULL) {
+ RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23, ERR_R_MALLOC_FAILURE);
+ return -1;
+ }
+ /*
+ * Caller is encouraged to pass zero-padded message created with
+ * BN_bn2binpad. Trouble is that since we can't read out of |from|'s
+ * bounds, it's impossible to have an invariant memory access pattern
+ * in case |from| was not zero-padded in advance.
+ */
+ for (from += flen, em += num, i = 0; i < num; i++) {
+ mask = ~constant_time_is_zero(flen);
+ flen -= 1 & mask;
+ from -= 1 & mask;
+ *--em = *from & mask;
+ }
+
+ good = constant_time_is_zero(em[0]);
+ good &= constant_time_eq(em[1], 2);
+ err = constant_time_select_int(good, 0, RSA_R_BLOCK_TYPE_IS_NOT_02);
+ mask = ~good;
+
+ /* scan over padding data */
+ found_zero_byte = 0;
+ threes_in_row = 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;
+
+ threes_in_row += 1 & ~found_zero_byte;
+ threes_in_row &= found_zero_byte | constant_time_eq(em[i], 3);
+ }
+
+ /*
+ * 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(zero_index, 2 + 8);
+ err = constant_time_select_int(mask | good, err,
+ RSA_R_NULL_BEFORE_BLOCK_MISSING);
+ mask = ~good;
+
+ good &= constant_time_ge(threes_in_row, 8);
+ err = constant_time_select_int(mask | good, err,
+ RSA_R_SSLV3_ROLLBACK_ATTACK);
+ mask = ~good;
+
+ /*
+ * 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.
+ */
+ good &= constant_time_ge(tlen, mlen);
+ err = constant_time_select_int(mask | good, err, RSA_R_DATA_TOO_LARGE);
+
+ /*
+ * Move the result in-place by |num|-RSA_PKCS1_PADDING_SIZE-|mlen| bytes to the left.
+ * Then if |good| move |mlen| bytes from |em|+RSA_PKCS1_PADDING_SIZE to |to|.
+ * Otherwise leave |to| unchanged.
+ * Copy the memory back in a way that does not reveal the size of
+ * the data being copied via a timing side channel. This requires copying
+ * parts of the buffer multiple times based on the bits set in the real
+ * length. Clear bits do a non-copy with identical access pattern.
+ * The loop below has overall complexity of O(N*log(N)).
+ */
+ tlen = constant_time_select_int(constant_time_lt(num - RSA_PKCS1_PADDING_SIZE, tlen),
+ num - RSA_PKCS1_PADDING_SIZE, tlen);
+ for (msg_index = 1; msg_index < num - RSA_PKCS1_PADDING_SIZE; msg_index <<= 1) {
+ mask = ~constant_time_eq(msg_index & (num - RSA_PKCS1_PADDING_SIZE - mlen), 0);
+ for (i = RSA_PKCS1_PADDING_SIZE; i < num - msg_index; i++)
+ em[i] = constant_time_select_8(mask, em[i + msg_index], em[i]);
+ }
+ for (i = 0; i < tlen; i++) {
+ mask = good & constant_time_lt(i, mlen);
+ to[i] = constant_time_select_8(mask, em[i + RSA_PKCS1_PADDING_SIZE], to[i]);
+ }
+
+ OPENSSL_clear_free(em, num);
+ RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23, err);
+ err_clear_last_constant_time(1 & good);
+ return constant_time_select_int(good, mlen, -1);
+}
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