android / platform / external / openssl / e67c7edd65f69f58535fb358a8665a23e5de62a4 / . / crypto / rsa / rsa_pk1.c

/* 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; | |

} |