diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/rsa/rsa_pk1.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/rsa/rsa_pk1.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/rsa/rsa_pk1.c b/openssl-1.1.0h/crypto/rsa/rsa_pk1.c new file mode 100644 index 0000000..aeeb32c --- /dev/null +++ b/openssl-1.1.0h/crypto/rsa/rsa_pk1.c @@ -0,0 +1,243 @@ +/* + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * 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 "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, + 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; + + /* + * 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, + 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_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; +} |