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|
/*
* Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2004, EdelKey Project. 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
*
* Originally written by Christophe Renou and Peter Sylvester,
* for the EdelKey project.
*/
#ifndef OPENSSL_NO_SRP
# include "internal/cryptlib.h"
# include "internal/evp_int.h"
# include <openssl/sha.h>
# include <openssl/srp.h>
# include <openssl/evp.h>
# include <openssl/buffer.h>
# include <openssl/rand.h>
# include <openssl/txt_db.h>
# include <openssl/err.h>
# define SRP_RANDOM_SALT_LEN 20
# define MAX_LEN 2500
/*
* Note that SRP uses its own variant of base 64 encoding. A different base64
* alphabet is used and no padding '=' characters are added. Instead we pad to
* the front with 0 bytes and subsequently strip off leading encoded padding.
* This variant is used for compatibility with other SRP implementations -
* notably libsrp, but also others. It is also required for backwards
* compatibility in order to load verifier files from other OpenSSL versions.
*/
/*
* Convert a base64 string into raw byte array representation.
* Returns the length of the decoded data, or -1 on error.
*/
static int t_fromb64(unsigned char *a, size_t alen, const char *src)
{
EVP_ENCODE_CTX *ctx;
int outl = 0, outl2 = 0;
size_t size, padsize;
const unsigned char *pad = (const unsigned char *)"00";
while (*src == ' ' || *src == '\t' || *src == '\n')
++src;
size = strlen(src);
padsize = 4 - (size & 3);
padsize &= 3;
/* Four bytes in src become three bytes output. */
if (size > INT_MAX || ((size + padsize) / 4) * 3 > alen)
return -1;
ctx = EVP_ENCODE_CTX_new();
if (ctx == NULL)
return -1;
/*
* This should never occur because 1 byte of data always requires 2 bytes of
* encoding, i.e.
* 0 bytes unencoded = 0 bytes encoded
* 1 byte unencoded = 2 bytes encoded
* 2 bytes unencoded = 3 bytes encoded
* 3 bytes unencoded = 4 bytes encoded
* 4 bytes unencoded = 6 bytes encoded
* etc
*/
if (padsize == 3) {
outl = -1;
goto err;
}
/* Valid padsize values are now 0, 1 or 2 */
EVP_DecodeInit(ctx);
evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_USE_SRP_ALPHABET);
/* Add any encoded padding that is required */
if (padsize != 0
&& EVP_DecodeUpdate(ctx, a, &outl, pad, padsize) < 0) {
outl = -1;
goto err;
}
if (EVP_DecodeUpdate(ctx, a, &outl2, (const unsigned char *)src, size) < 0) {
outl = -1;
goto err;
}
outl += outl2;
EVP_DecodeFinal(ctx, a + outl, &outl2);
outl += outl2;
/* Strip off the leading padding */
if (padsize != 0) {
if ((int)padsize >= outl) {
outl = -1;
goto err;
}
/*
* If we added 1 byte of padding prior to encoding then we have 2 bytes
* of "real" data which gets spread across 4 encoded bytes like this:
* (6 bits pad)(2 bits pad | 4 bits data)(6 bits data)(6 bits data)
* So 1 byte of pre-encoding padding results in 1 full byte of encoded
* padding.
* If we added 2 bytes of padding prior to encoding this gets encoded
* as:
* (6 bits pad)(6 bits pad)(4 bits pad | 2 bits data)(6 bits data)
* So 2 bytes of pre-encoding padding results in 2 full bytes of encoded
* padding, i.e. we have to strip the same number of bytes of padding
* from the encoded data as we added to the pre-encoded data.
*/
memmove(a, a + padsize, outl - padsize);
outl -= padsize;
}
err:
EVP_ENCODE_CTX_free(ctx);
return outl;
}
/*
* Convert a raw byte string into a null-terminated base64 ASCII string.
* Returns 1 on success or 0 on error.
*/
static int t_tob64(char *dst, const unsigned char *src, int size)
{
EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
int outl = 0, outl2 = 0;
unsigned char pad[2] = {0, 0};
size_t leadz = 0;
if (ctx == NULL)
return 0;
EVP_EncodeInit(ctx);
evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_NO_NEWLINES
| EVP_ENCODE_CTX_USE_SRP_ALPHABET);
/*
* We pad at the front with zero bytes until the length is a multiple of 3
* so that EVP_EncodeUpdate/EVP_EncodeFinal does not add any of its own "="
* padding
*/
leadz = 3 - (size % 3);
if (leadz != 3
&& !EVP_EncodeUpdate(ctx, (unsigned char *)dst, &outl, pad,
leadz)) {
EVP_ENCODE_CTX_free(ctx);
return 0;
}
if (!EVP_EncodeUpdate(ctx, (unsigned char *)dst + outl, &outl2, src,
size)) {
EVP_ENCODE_CTX_free(ctx);
return 0;
}
outl += outl2;
EVP_EncodeFinal(ctx, (unsigned char *)dst + outl, &outl2);
outl += outl2;
/* Strip the encoded padding at the front */
if (leadz != 3) {
memmove(dst, dst + leadz, outl - leadz);
dst[outl - leadz] = '\0';
}
EVP_ENCODE_CTX_free(ctx);
return 1;
}
void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
{
if (user_pwd == NULL)
return;
BN_free(user_pwd->s);
BN_clear_free(user_pwd->v);
OPENSSL_free(user_pwd->id);
OPENSSL_free(user_pwd->info);
OPENSSL_free(user_pwd);
}
static SRP_user_pwd *SRP_user_pwd_new(void)
{
SRP_user_pwd *ret;
if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
/* SRPerr(SRP_F_SRP_USER_PWD_NEW, ERR_R_MALLOC_FAILURE); */ /*ckerr_ignore*/
return NULL;
}
ret->N = NULL;
ret->g = NULL;
ret->s = NULL;
ret->v = NULL;
ret->id = NULL;
ret->info = NULL;
return ret;
}
static void SRP_user_pwd_set_gN(SRP_user_pwd
|