--- /dev/null
+/* 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 <stdio.h>
+#include "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,
+ 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<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,
+ 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,
+ 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_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;
+ }
projects / cassiopeia.git / blobdiff