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freebsd/contrib/bsnmp/lib/snmpcrypto.c
Shteryana Shopova 2b8026620c Silence the compiler warnings in libbsnmp by removing several (now) 
unsed parameters.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	philip@
2010-12-16 11:20:37 +00:00

403 lines
10 KiB
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/*-
* Copyright (c) 2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Shteryana Sotirova Shopova under
* sponsorship from the FreeBSD Foundation.
*
* 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 above 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#ifdef HAVE_STDINT_H
#include <stdint.h>
#elif defined(HAVE_INTTYPES_H)
#include <inttypes.h>
#endif
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <netinet/in.h>
#ifdef HAVE_LIBCRYPTO
#include <openssl/evp.h>
#endif
#include "asn1.h"
#include "snmp.h"
#include "snmppriv.h"
#define SNMP_PRIV_AES_IV_SIZ 16
#define SNMP_EXTENDED_KEY_SIZ 64
#define SNMP_AUTH_KEY_LOOPCNT 1048576
#define SNMP_AUTH_BUF_SIZE 72
static const uint8_t ipad = 0x36;
static const uint8_t opad = 0x5c;
#ifdef HAVE_LIBCRYPTO
static int32_t
snmp_digest_init(const struct snmp_user *user, EVP_MD_CTX *ctx,
const EVP_MD **dtype, uint32_t *keylen)
{
if (user->auth_proto == SNMP_AUTH_HMAC_MD5) {
*dtype = EVP_md5();
*keylen = SNMP_AUTH_HMACMD5_KEY_SIZ;
} else if (user->auth_proto == SNMP_AUTH_HMAC_SHA) {
*dtype = EVP_sha1();
*keylen = SNMP_AUTH_HMACSHA_KEY_SIZ;
} else if (user->auth_proto == SNMP_AUTH_NOAUTH)
return (0);
else {
snmp_error("unknown authentication option - %d",
user->auth_proto);
return (-1);
}
if (EVP_DigestInit(ctx, *dtype) != 1)
return (-1);
return (1);
}
enum snmp_code
snmp_pdu_calc_digest(const struct snmp_pdu *pdu, uint8_t *digest)
{
uint8_t md[EVP_MAX_MD_SIZE], extkey[SNMP_EXTENDED_KEY_SIZ];
uint8_t key1[SNMP_EXTENDED_KEY_SIZ], key2[SNMP_EXTENDED_KEY_SIZ];
uint32_t i, keylen, olen;
int32_t err;
const EVP_MD *dtype;
EVP_MD_CTX ctx;
err = snmp_digest_init(&pdu->user, &ctx, &dtype, &keylen);
if (err < 0)
return (SNMP_CODE_BADDIGEST);
else if (err == 0)
return (SNMP_CODE_OK);
memset(pdu->digest_ptr, 0, sizeof(pdu->msg_digest));
memcpy(extkey, pdu->user.auth_key, keylen);
memset(extkey + keylen, 0, sizeof(extkey) - keylen);
for (i = 0; i < SNMP_EXTENDED_KEY_SIZ; i++) {
key1[i] = extkey[i] ^ ipad;
key2[i] = extkey[i] ^ opad;
}
if (EVP_DigestUpdate(&ctx, key1, SNMP_EXTENDED_KEY_SIZ) != 1 ||
EVP_DigestUpdate(&ctx, pdu->outer_ptr, pdu->outer_len) != 1 ||
EVP_DigestFinal(&ctx, md, &olen) != 1)
goto failed;
if (EVP_DigestInit(&ctx, dtype) != 1 ||
EVP_DigestUpdate(&ctx, key2, SNMP_EXTENDED_KEY_SIZ) != 1 ||
EVP_DigestUpdate(&ctx, md, olen) != 1 ||
EVP_DigestFinal(&ctx, md, &olen) != 1)
goto failed;
if (olen < SNMP_USM_AUTH_SIZE) {
snmp_error("bad digest size - %d", olen);
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_BADDIGEST);
}
memcpy(digest, md, SNMP_USM_AUTH_SIZE);
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_OK);
failed:
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_BADDIGEST);
}
static int32_t
snmp_pdu_cipher_init(const struct snmp_pdu *pdu, int32_t len,
const EVP_CIPHER **ctype, uint8_t *piv)
{
int i;
uint32_t netint;
if (pdu->user.priv_proto == SNMP_PRIV_DES) {
if (len % 8 != 0)
return (-1);
*ctype = EVP_des_cbc();
memcpy(piv, pdu->msg_salt, sizeof(pdu->msg_salt));
for (i = 0; i < 8; i++)
piv[i] = piv[i] ^ pdu->user.priv_key[8 + i];
} else if (pdu->user.priv_proto == SNMP_PRIV_AES) {
*ctype = EVP_aes_128_cfb128();
netint = htonl(pdu->engine.engine_boots);
memcpy(piv, &netint, sizeof(netint));
piv += sizeof(netint);
netint = htonl(pdu->engine.engine_time);
memcpy(piv, &netint, sizeof(netint));
piv += sizeof(netint);
memcpy(piv, pdu->msg_salt, sizeof(pdu->msg_salt));
} else if (pdu->user.priv_proto == SNMP_PRIV_NOPRIV)
return (0);
else {
snmp_error("unknown privacy option - %d", pdu->user.priv_proto);
return (-1);
}
return (1);
}
enum snmp_code
snmp_pdu_encrypt(const struct snmp_pdu *pdu)
{
int32_t err, olen;
uint8_t iv[SNMP_PRIV_AES_IV_SIZ];
const EVP_CIPHER *ctype;
EVP_CIPHER_CTX ctx;
err = snmp_pdu_cipher_init(pdu, pdu->scoped_len, &ctype, iv);
if (err < 0)
return (SNMP_CODE_EDECRYPT);
else if (err == 0)
return (SNMP_CODE_OK);
if (EVP_EncryptInit(&ctx, ctype, pdu->user.priv_key, iv) != 1)
return (SNMP_CODE_FAILED);
if (EVP_EncryptUpdate(&ctx, pdu->scoped_ptr, &olen, pdu->scoped_ptr,
pdu->scoped_len) != 1 ||
EVP_EncryptFinal(&ctx, pdu->scoped_ptr + olen, &olen) != 1) {
EVP_CIPHER_CTX_cleanup(&ctx);
return (SNMP_CODE_FAILED);
}
EVP_CIPHER_CTX_cleanup(&ctx);
return (SNMP_CODE_OK);
}
enum snmp_code
snmp_pdu_decrypt(const struct snmp_pdu *pdu)
{
int32_t err, olen;
uint8_t iv[SNMP_PRIV_AES_IV_SIZ];
const EVP_CIPHER *ctype;
EVP_CIPHER_CTX ctx;
err = snmp_pdu_cipher_init(pdu, pdu->scoped_len, &ctype, iv);
if (err < 0)
return (SNMP_CODE_EDECRYPT);
else if (err == 0)
return (SNMP_CODE_OK);
if (EVP_DecryptInit(&ctx, ctype, pdu->user.priv_key, iv) != 1 ||
EVP_CIPHER_CTX_set_padding(&ctx, 0) != 1)
return (SNMP_CODE_EDECRYPT);
if (EVP_DecryptUpdate(&ctx, pdu->scoped_ptr, &olen, pdu->scoped_ptr,
pdu->scoped_len) != 1 ||
EVP_DecryptFinal(&ctx, pdu->scoped_ptr + olen, &olen) != 1) {
EVP_CIPHER_CTX_cleanup(&ctx);
return (SNMP_CODE_EDECRYPT);
}
EVP_CIPHER_CTX_cleanup(&ctx);
return (SNMP_CODE_OK);
}
/* [RFC 3414] - A.2. Password to Key Algorithm */
enum snmp_code
snmp_passwd_to_keys(struct snmp_user *user, char *passwd)
{
int err, loop, i, pwdlen;
uint32_t keylen, olen;
const EVP_MD *dtype;
EVP_MD_CTX ctx;
uint8_t authbuf[SNMP_AUTH_BUF_SIZE];
if (passwd == NULL || user == NULL)
return (SNMP_CODE_FAILED);
err = snmp_digest_init(user, &ctx, &dtype, &keylen);
if (err < 0)
return (SNMP_CODE_BADDIGEST);
else if (err == 0)
return (SNMP_CODE_OK);
memset(user->auth_key, 0, sizeof(user->auth_key));
pwdlen = strlen(passwd);
for (loop = 0; loop < SNMP_AUTH_KEY_LOOPCNT; loop += i) {
for (i = 0; i < SNMP_EXTENDED_KEY_SIZ; i++)
authbuf[i] = passwd[(loop + i) % pwdlen];
if (EVP_DigestUpdate(&ctx, authbuf, SNMP_EXTENDED_KEY_SIZ) != 1)
goto failed;
}
if (EVP_DigestFinal(&ctx, user->auth_key, &olen) != 1)
goto failed;
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_OK);
failed:
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_BADDIGEST);
}
/* [RFC 3414] - 2.6. Key Localization Algorithm */
enum snmp_code
snmp_get_local_keys(struct snmp_user *user, uint8_t *eid, uint32_t elen)
{
int err;
uint32_t keylen, olen;
const EVP_MD *dtype;
EVP_MD_CTX ctx;
uint8_t authbuf[SNMP_AUTH_BUF_SIZE];
if (user == NULL || eid == NULL || elen > SNMP_ENGINE_ID_SIZ)
return (SNMP_CODE_FAILED);
memset(user->priv_key, 0, sizeof(user->priv_key));
memset(authbuf, 0, sizeof(authbuf));
err = snmp_digest_init(user, &ctx, &dtype, &keylen);
if (err < 0)
return (SNMP_CODE_BADDIGEST);
else if (err == 0)
return (SNMP_CODE_OK);
memcpy(authbuf, user->auth_key, keylen);
memcpy(authbuf + keylen, eid, elen);
memcpy(authbuf + keylen + elen, user->auth_key, keylen);
if (EVP_DigestUpdate(&ctx, authbuf, 2 * keylen + elen) != 1 ||
EVP_DigestFinal(&ctx, user->auth_key, &olen) != 1) {
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_BADDIGEST);
}
EVP_MD_CTX_cleanup(&ctx);
if (user->priv_proto != SNMP_PRIV_NOPRIV)
memcpy(user->priv_key, user->auth_key, sizeof(user->priv_key));
return (SNMP_CODE_OK);
}
enum snmp_code
snmp_calc_keychange(struct snmp_user *user, uint8_t *keychange)
{
int32_t err, rvalue[SNMP_AUTH_HMACSHA_KEY_SIZ / 4];
uint32_t i, keylen, olen;
const EVP_MD *dtype;
EVP_MD_CTX ctx;
err = snmp_digest_init(user, &ctx, &dtype, &keylen);
if (err < 0)
return (SNMP_CODE_BADDIGEST);
else if (err == 0)
return (SNMP_CODE_OK);
for (i = 0; i < keylen / 4; i++)
rvalue[i] = random();
memcpy(keychange, user->auth_key, keylen);
memcpy(keychange + keylen, rvalue, keylen);
if (EVP_DigestUpdate(&ctx, keychange, 2 * keylen) != 1 ||
EVP_DigestFinal(&ctx, keychange, &olen) != 1) {
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_BADDIGEST);
}
EVP_MD_CTX_cleanup(&ctx);
return (SNMP_CODE_OK);
}
#else /* !HAVE_LIBCRYPTO */
enum snmp_code
snmp_pdu_calc_digest(const struct snmp_pdu *pdu, uint8_t *digest __unused)
{
if (pdu->user.auth_proto != SNMP_AUTH_NOAUTH)
return (SNMP_CODE_BADSECLEVEL);
return (SNMP_CODE_OK);
}
enum snmp_code
snmp_pdu_encrypt(const struct snmp_pdu *pdu)
{
if (pdu->user.priv_proto != SNMP_PRIV_NOPRIV)
return (SNMP_CODE_BADSECLEVEL);
return (SNMP_CODE_OK);
}
enum snmp_code
snmp_pdu_decrypt(const struct snmp_pdu *pdu)
{
if (pdu->user.priv_proto != SNMP_PRIV_NOPRIV)
return (SNMP_CODE_BADSECLEVEL);
return (SNMP_CODE_OK);
}
int
snmp_passwd_to_keys(struct snmp_user *user, char *passwd __unused)
{
if (user->auth_proto == SNMP_AUTH_NOAUTH &&
user->priv_proto == SNMP_PRIV_NOPRIV)
return (SNMP_CODE_OK);
errno = EPROTONOSUPPORT;
return (SNMP_CODE_FAILED);
}
int
snmp_get_local_keys(struct snmp_user *user, uint8_t *eid __unused,
uint32_t elen __unused)
{
if (user->auth_proto == SNMP_AUTH_NOAUTH &&
user->priv_proto == SNMP_PRIV_NOPRIV)
return (SNMP_CODE_OK);
errno = EPROTONOSUPPORT;
return (SNMP_CODE_FAILED);
}
enum snmp_code
snmp_calc_keychange(struct snmp_user *user __unused,
uint8_t *keychange __unused)
{
errno = EPROTONOSUPPORT;
return (SNMP_CODE_FAILED);
}
#endif /* HAVE_LIBCRYPTO */
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