/* crypto/rsa/rsa_pk1.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* 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.]
*/
#include "constant_time_locl.h"
#include
#include "cryptlib.h"
#include
#include
#include
int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
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,
const unsigned char *from, int flen, int num)
{
int i,j;
const 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 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,
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 num)
goto err;
if (num < 11)
goto err;
em = OPENSSL_malloc(num);
if (em == NULL)
{
RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2, ERR_R_MALLOC_FAILURE);
return -1;
}
memset(em, 0, num);
/*
* 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.
* TODO(emilia): this could be addressed at the call site,
* see BoringSSL commit 0aa0767340baf925bda4804882aab0cb974b2d26.
*/
if (!good)
{
mlen = -1;
goto err;
}
memcpy(to, em + msg_index, mlen);
err:
if (em != NULL)
OPENSSL_free(em);
if (mlen == -1)
RSAerr(RSA_F_RSA_PADDING_CHECK_PKCS1_TYPE_2, RSA_R_PKCS_DECODING_ERROR);
return mlen;
}