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NetBSD/lib/libresolv/hmac_link.c

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/* $NetBSD: hmac_link.c,v 1.3 2016/03/07 14:35:39 christos Exp $ */
/*
* Portions Copyright (c) 1995-1998 by Trusted Information Systems, Inc.
*
* Permission to use, copy modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND TRUSTED INFORMATION SYSTEMS
* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
* TRUSTED INFORMATION SYSTEMS BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THE SOFTWARE.
*/
#include <sys/cdefs.h>
#if 0
static const char rcsid[] = "Header: /proj/cvs/prod/libbind/dst/hmac_link.c,v 1.8 2007/09/24 17:18:25 each Exp ";
#else
__RCSID("$NetBSD: hmac_link.c,v 1.3 2016/03/07 14:35:39 christos Exp $");
#endif
/*%
* This file contains an implementation of the HMAC-MD5 algorithm.
*/
#include "port_before.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <sys/param.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include "dst_internal.h"
#include <md5.h>
#include "port_after.h"
#define HMAC_LEN 64
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5c
#define MD5_LEN 16
typedef struct hmackey {
u_char hk_ipad[64], hk_opad[64];
} HMAC_Key;
/**************************************************************************
* dst_hmac_md5_sign
* Call HMAC signing functions to sign a block of data.
* There are three steps to signing, INIT (initialize structures),
* UPDATE (hash (more) data), FINAL (generate a signature). This
* routine performs one or more of these steps.
* Parameters
* mode SIG_MODE_INIT, SIG_MODE_UPDATE and/or SIG_MODE_FINAL.
* priv_key key to use for signing.
* context the context to be used in this digest
* data data to be signed.
* len length in bytes of data.
* signature location to store signature.
* sig_len size of the signature location
* returns
* N Success on SIG_MODE_FINAL = returns signature length in bytes
* 0 Success on SIG_MODE_INIT and UPDATE
* <0 Failure
*/
static int
dst_hmac_md5_sign(const int mode, DST_KEY *d_key, void **context,
const u_char *data, const int len,
u_char *signature, const int sig_len)
{
HMAC_Key *key;
int sign_len = 0;
MD5_CTX *ctx = NULL;
if (d_key == NULL || d_key->dk_KEY_struct == NULL)
return (-1);
if (mode & SIG_MODE_INIT)
ctx = (MD5_CTX *) malloc(sizeof(*ctx));
else if (context)
ctx = (MD5_CTX *) *context;
if (ctx == NULL)
return (-1);
key = (HMAC_Key *) d_key->dk_KEY_struct;
if (mode & SIG_MODE_INIT) {
MD5Init(ctx);
MD5Update(ctx, key->hk_ipad, HMAC_LEN);
}
if ((mode & SIG_MODE_UPDATE) && (data && len > 0))
MD5Update(ctx, data, (unsigned int)len);
if (mode & SIG_MODE_FINAL) {
if (signature == NULL || sig_len < MD5_LEN)
return (SIGN_FINAL_FAILURE);
MD5Final(signature, ctx);
/* perform outer MD5 */
MD5Init(ctx);
MD5Update(ctx, key->hk_opad, HMAC_LEN);
MD5Update(ctx, signature, MD5_LEN);
MD5Final(signature, ctx);
sign_len = MD5_LEN;
SAFE_FREE(ctx);
}
else {
if (context == NULL)
return (-1);
*context = (void *) ctx;
}
return (sign_len);
}
/**************************************************************************
* dst_hmac_md5_verify()
* Calls HMAC verification routines. There are three steps to
* verification, INIT (initialize structures), UPDATE (hash (more) data),
* FINAL (generate a signature). This routine performs one or more of
* these steps.
* Parameters
* mode SIG_MODE_INIT, SIG_MODE_UPDATE and/or SIG_MODE_FINAL.
* dkey key to use for verify.
* data data signed.
* len length in bytes of data.
* signature signature.
* sig_len length in bytes of signature.
* returns
* 0 Success
* <0 Failure
*/
static int
dst_hmac_md5_verify(const int mode, DST_KEY *d_key, void **context,
const u_char *data, const int len,
const u_char *signature, const int sig_len)
{
HMAC_Key *key;
MD5_CTX *ctx = NULL;
if (d_key == NULL || d_key->dk_KEY_struct == NULL)
return (-1);
if (mode & SIG_MODE_INIT)
ctx = (MD5_CTX *) malloc(sizeof(*ctx));
else if (context)
ctx = (MD5_CTX *) *context;
if (ctx == NULL)
return (-1);
key = (HMAC_Key *) d_key->dk_KEY_struct;
if (mode & SIG_MODE_INIT) {
MD5Init(ctx);
MD5Update(ctx, key->hk_ipad, HMAC_LEN);
}
if ((mode & SIG_MODE_UPDATE) && (data && len > 0))
MD5Update(ctx, data, (unsigned int)len);
if (mode & SIG_MODE_FINAL) {
u_char digest[MD5_LEN];
if (signature == NULL || key == NULL || sig_len != MD5_LEN)
return (VERIFY_FINAL_FAILURE);
MD5Final(digest, ctx);
/* perform outer MD5 */
MD5Init(ctx);
MD5Update(ctx, key->hk_opad, HMAC_LEN);
MD5Update(ctx, digest, MD5_LEN);
MD5Final(digest, ctx);
SAFE_FREE(ctx);
if (memcmp(digest, signature, MD5_LEN) != 0)
return (VERIFY_FINAL_FAILURE);
}
else {
if (context == NULL)
return (-1);
*context = (void *) ctx;
}
return (0);
}
/**************************************************************************
* dst_buffer_to_hmac_md5
* Converts key from raw data to an HMAC Key
* This function gets in a pointer to the data
* Parameters
* hkey the HMAC key to be filled in
* key the key in raw format
* keylen the length of the key
* Return
* 0 Success
* <0 Failure
*/
static int
dst_buffer_to_hmac_md5(DST_KEY *dkey, const u_char *key, const int keylen)
{
int i;
HMAC_Key *hkey = NULL;
MD5_CTX ctx;
int local_keylen = keylen;
u_char tk[MD5_LEN];
if (dkey == NULL || key == NULL || keylen < 0)
return (-1);
if ((hkey = (HMAC_Key *) malloc(sizeof(HMAC_Key))) == NULL)
return (-2);
memset(hkey->hk_ipad, 0, sizeof(hkey->hk_ipad));
memset(hkey->hk_opad, 0, sizeof(hkey->hk_opad));
/* if key is longer than HMAC_LEN bytes reset it to key=MD5(key) */
if (keylen > HMAC_LEN) {
MD5Init(&ctx);
MD5Update(&ctx, key, (unsigned int)keylen);
MD5Final(tk, &ctx);
memset((void *) &ctx, 0, sizeof(ctx));
key = tk;
local_keylen = MD5_LEN;
}
/* start out by storing key in pads */
memcpy(hkey->hk_ipad, key, local_keylen);
memcpy(hkey->hk_opad, key, local_keylen);
/* XOR key with hk_ipad and opad values */
for (i = 0; i < HMAC_LEN; i++) {
hkey->hk_ipad[i] ^= HMAC_IPAD;
hkey->hk_opad[i] ^= HMAC_OPAD;
}
dkey->dk_key_size = local_keylen;
dkey->dk_KEY_struct = (void *) hkey;
return (1);
}
/**************************************************************************
* dst_hmac_md5_key_to_file_format
* Encodes an HMAC Key into the portable file format.
* Parameters
* hkey HMAC KEY structure
* buff output buffer
* buff_len size of output buffer
* Return
* 0 Failure - null input hkey
* -1 Failure - not enough space in output area
* N Success - Length of data returned in buff
*/
static int
dst_hmac_md5_key_to_file_format(const DST_KEY *dkey, char *buff,
const int buff_len)
{
char *bp;
#define BUF_LEFT (size_t)(buff_len - (bp - buff))
int len, key_len;
u_char key[HMAC_LEN];
HMAC_Key *hkey;
static const char keystr[] = "Key: ";
if (buff == NULL)
return -1; /*%< no output area */
if (dkey == NULL || dkey->dk_KEY_struct == NULL)
return 0;
/* write file header */
hkey = (HMAC_Key *) dkey->dk_KEY_struct;
len = snprintf(buff, buff_len, KEY_FILE_FMT_STR, KEY_FILE_FORMAT,
KEY_HMAC_MD5, "HMAC");
if (len < 0 || len >= buff_len)
return -1; /*%< not enough space in output area */
bp = buff + len;
if (BUF_LEFT < sizeof(keystr))
return -1;
memcpy(bp, keystr, sizeof(keystr) - 1);
bp += sizeof(keystr) - 1;
for (key_len = 0; key_len < HMAC_LEN; key_len++)
key[key_len] = hkey->hk_ipad[key_len] ^ HMAC_IPAD;
for (key_len = HMAC_LEN - 1; key_len >= 0; key_len--)
if (key[key_len] != 0)
break;
key_len++;
len = b64_ntop(key, key_len, bp, BUF_LEFT);
if (len < 0)
return -1;
bp += len;
if (BUF_LEFT < 2)
return -1;
*(bp++) = '\n';
memset(bp, 0, BUF_LEFT);
return (int)(bp - buff);
}
/**************************************************************************
* dst_hmac_md5_key_from_file_format
* Converts contents of a key file into an HMAC key.
* Parameters
* hkey structure to put key into
* buff buffer containing the encoded key
* buff_len the length of the buffer
* Return
* n >= 0 Foot print of the key converted
* n < 0 Error in conversion
*/
static int
dst_hmac_md5_key_from_file_format(DST_KEY *dkey, const char *buff,
const int buff_len)
{
const char *p = buff, *eol;
u_char key[HMAC_LEN+1]; /* b64_pton needs more than 64 bytes do decode
* it should probably be fixed rather than doing
* this
*/
u_char *tmp;
int key_len, len;
if (dkey == NULL)
return (-2);
if (buff == NULL || buff_len < 0)
return (-1);
memset(key, 0, sizeof(key));
if (!dst_s_verify_str(&p, "Key: "))
return (-3);
eol = strchr(p, '\n');
if (eol == NULL)
return (-4);
len = (int)(eol - p);
tmp = malloc(len + 2);
if (tmp == NULL)
return (-5);
memcpy(tmp, p, len);
*(tmp + len) = 0x0;
key_len = b64_pton((char *)tmp, key, HMAC_LEN+1); /*%< see above */
SAFE_FREE2(tmp, len + 2);
if (dst_buffer_to_hmac_md5(dkey, key, key_len) < 0) {
return (-6);
}
return (0);
}
/*%
* dst_hmac_md5_to_dns_key()
* function to extract hmac key from DST_KEY structure
* intput:
* in_key: HMAC-MD5 key
* output:
* out_str: buffer to write ot
* out_len: size of output buffer
* returns:
* number of bytes written to output buffer
*/
static int
dst_hmac_md5_to_dns_key(const DST_KEY *in_key, u_char *out_str,
const int out_len)
{
HMAC_Key *hkey;
int i;
if (in_key == NULL || in_key->dk_KEY_struct == NULL ||
out_len <= in_key->dk_key_size || out_str == NULL)
return (-1);
hkey = (HMAC_Key *) in_key->dk_KEY_struct;
for (i = 0; i < in_key->dk_key_size; i++)
out_str[i] = hkey->hk_ipad[i] ^ HMAC_IPAD;
return (i);
}
/**************************************************************************
* dst_hmac_md5_compare_keys
* Compare two keys for equality.
* Return
* 0 The keys are equal
* NON-ZERO The keys are not equal
*/
static int
dst_hmac_md5_compare_keys(const DST_KEY *key1, const DST_KEY *key2)
{
HMAC_Key *hkey1 = (HMAC_Key *) key1->dk_KEY_struct;
HMAC_Key *hkey2 = (HMAC_Key *) key2->dk_KEY_struct;
return memcmp(hkey1->hk_ipad, hkey2->hk_ipad, HMAC_LEN);
}
/**************************************************************************
* dst_hmac_md5_free_key_structure
* Frees all (none) dynamically allocated structures in hkey
*/
static void *
dst_hmac_md5_free_key_structure(void *key)
{
HMAC_Key *hkey = key;
SAFE_FREE(hkey);
return (NULL);
}
/***************************************************************************
* dst_hmac_md5_generate_key
* Creates a HMAC key of size size with a maximum size of 63 bytes
* generating a HMAC key larger than 63 bytes makes no sense as that key
* is digested before use.
*/
static int
/*ARGSUSED*/
dst_hmac_md5_generate_key(DST_KEY *key, const int nothing)
{
return (-1);
}
/*%
* dst_hmac_md5_init() Function to answer set up function pointers for HMAC
* related functions
*/
int
#ifdef SUNW_LIBMD5
dst_md5_hmac_init(void)
#else
dst_hmac_md5_init(void)
#endif
{
if (dst_t_func[KEY_HMAC_MD5] != NULL)
return (1);
dst_t_func[KEY_HMAC_MD5] = malloc(sizeof(struct dst_func));
if (dst_t_func[KEY_HMAC_MD5] == NULL)
return (0);
memset(dst_t_func[KEY_HMAC_MD5], 0, sizeof(struct dst_func));
dst_t_func[KEY_HMAC_MD5]->sign = dst_hmac_md5_sign;
dst_t_func[KEY_HMAC_MD5]->verify = dst_hmac_md5_verify;
dst_t_func[KEY_HMAC_MD5]->compare = dst_hmac_md5_compare_keys;
dst_t_func[KEY_HMAC_MD5]->generate = dst_hmac_md5_generate_key;
dst_t_func[KEY_HMAC_MD5]->destroy = dst_hmac_md5_free_key_structure;
dst_t_func[KEY_HMAC_MD5]->to_dns_key = dst_hmac_md5_to_dns_key;
dst_t_func[KEY_HMAC_MD5]->from_dns_key = dst_buffer_to_hmac_md5;
dst_t_func[KEY_HMAC_MD5]->to_file_fmt = dst_hmac_md5_key_to_file_format;
dst_t_func[KEY_HMAC_MD5]->from_file_fmt = dst_hmac_md5_key_from_file_format;
return (1);
}
/*! \file */
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