/*******************************************************************-o-******
* generate_Ku
*
* Parameters:
* *hashtype MIB OID for the transform type for hashing.
* hashtype_len Length of OID value.
* *P Pre-allocated bytes of passpharase.
* pplen Length of passphrase.
* *Ku Buffer to contain Ku.
* *kulen Length of Ku buffer.
*
* Returns:
* SNMPERR_SUCCESS Success.
* SNMPERR_GENERR All errors.
*
*
* Convert a passphrase into a master user key, Ku, according to the
* algorithm given in RFC 2274 concerning the SNMPv3 User Security Model (USM)
* as follows:
*
* Expand the passphrase to fill the passphrase buffer space, if necessary,
* concatenation as many duplicates as possible of P to itself. If P is
* larger than the buffer space, truncate it to fit.
*
* Then hash the result with the given hashtype transform. Return
* the result as Ku.
*
* If successful, kulen contains the size of the hash written to Ku.
*
* NOTE Passphrases less than USM_LENGTH_P_MIN characters in length
* cause an error to be returned.
* (Punt this check to the cmdline apps? XXX)
*/
int
generate_Ku(const oid * hashtype, u_int hashtype_len,
const u_char * P, size_t pplen, u_char * Ku, size_t * kulen)
#if defined(NETSNMP_USE_INTERNAL_MD5) || defined(NETSNMP_USE_OPENSSL) || defined(NETSNMP_USE_INTERNAL_CRYPTO)
{
int rval = SNMPERR_SUCCESS,
nbytes = USM_LENGTH_EXPANDED_PASSPHRASE;
#if !defined(NETSNMP_USE_OPENSSL) && \
defined(NETSNMP_USE_INTERNAL_MD5) || defined(NETSNMP_USE_INTERNAL_CRYPTO)
int ret;
#endif
u_int i, pindex = 0;
u_char buf[USM_LENGTH_KU_HASHBLOCK], *bufp;
#ifdef NETSNMP_USE_OPENSSL
EVP_MD_CTX *ctx = NULL;
#elif NETSNMP_USE_INTERNAL_CRYPTO
SHA_CTX csha1;
MD5_CTX cmd5;
char cryptotype = 0;
#define TYPE_MD5 1
#define TYPE_SHA1 2
#else
MDstruct MD;
#endif
/*
* Sanity check.
*/
if (!hashtype || !P || !Ku || !kulen || (*kulen <= 0)
|| (hashtype_len != USM_LENGTH_OID_TRANSFORM)) {
QUITFUN(SNMPERR_GENERR, generate_Ku_quit);
}
if (pplen < USM_LENGTH_P_MIN) {
snmp_log(LOG_ERR, "Error: passphrase chosen is below the length "
"requirements of the USM (min=%d).\n",USM_LENGTH_P_MIN);
snmp_set_detail("The supplied password length is too short.");
QUITFUN(SNMPERR_GENERR, generate_Ku_quit);
}
/*
* Setup for the transform type.
*/
#ifdef NETSNMP_USE_OPENSSL
#ifdef HAVE_EVP_MD_CTX_CREATE
ctx = EVP_MD_CTX_create();
#else
ctx = malloc(sizeof(*ctx));
EVP_MD_CTX_init(ctx);
#endif
#ifndef NETSNMP_DISABLE_MD5
if (ISTRANSFORM(hashtype, HMACMD5Auth))
EVP_DigestInit(ctx, EVP_md5());
else
#endif
if (ISTRANSFORM(hashtype, HMACSHA1Auth))
EVP_DigestInit(ctx, EVP_sha1());
else
QUITFUN(SNMPERR_GENERR, generate_Ku_quit);
#elif NETSNMP_USE_INTERNAL_CRYPTO
#ifndef NETSNMP_DISABLE_MD5
if (ISTRANSFORM(hashtype, HMACMD5Auth)) {
MD5_Init(&cmd5);
cryptotype = TYPE_MD5;
} else
#endif
if (ISTRANSFORM(hashtype, HMACSHA1Auth)) {
SHA1_Init(&csha1);
cryptotype = TYPE_SHA1;
} else {
return (SNMPERR_GENERR);
}
#else
MDbegin(&MD);
#endif /* NETSNMP_USE_OPENSSL */
while (nbytes > 0) {
bufp = buf;
for (i = 0; i < USM_LENGTH_KU_HASHBLOCK; i++) {
*bufp++ = P[pindex++ % pplen];
}
#ifdef NETSNMP_USE_OPENSSL
EVP_DigestUpdate(ctx, buf, USM_LENGTH_KU_HASHBLOCK);
#elif NETSNMP_USE_INTERNAL_CRYPTO
if (TYPE_SHA1 == cryptotype) {
rval = !SHA1_Update(&csha1, buf, USM_LENGTH_KU_HASHBLOCK);
} else {
rval = !MD5_Update(&cmd5, buf, USM_LENGTH_KU_HASHBLOCK);
}
if (rval != 0) {
return SNMPERR_USM_ENCRYPTIONERROR;
}
#elif NETSNMP_USE_INTERNAL_MD5
if (MDupdate(&MD, buf, USM_LENGTH_KU_HASHBLOCK * 8)) {
rval = SNMPERR_USM_ENCRYPTIONERROR;
goto md5_fin;
}
#endif /* NETSNMP_USE_OPENSSL */
nbytes -= USM_LENGTH_KU_HASHBLOCK;
}
#ifdef NETSNMP_USE_OPENSSL
{
unsigned int tmp_len;
tmp_len = *kulen;
EVP_DigestFinal(ctx, (unsigned char *) Ku, &tmp_len);
*kulen = tmp_len;
/*
* what about free()
*/
}
#elif NETSNMP_USE_INTERNAL_CRYPTO
if (TYPE_SHA1 == cryptotype) {
SHA1_Final(Ku, &csha1);
} else {
MD5_Final(Ku, &cmd5);
}
ret = sc_get_properlength(hashtype, hashtype_len);
if (ret == SNMPERR_GENERR)
return SNMPERR_GENERR;
*kulen = ret;
#elif NETSNMP_USE_INTERNAL_MD5
if (MDupdate(&MD, buf, 0)) {
rval = SNMPERR_USM_ENCRYPTIONERROR;
goto md5_fin;
}
ret = sc_get_properlength(hashtype, hashtype_len);
if (ret == SNMPERR_GENERR)
return SNMPERR_GENERR;
*kulen = ret;
MDget(&MD, Ku, *kulen);
md5_fin:
memset(&MD, 0, sizeof(MD));
#endif /* NETSNMP_USE_INTERNAL_MD5 */
#ifdef NETSNMP_ENABLE_TESTING_CODE
DEBUGMSGTL(("generate_Ku", "generating Ku (from %s): ", P));
for (i = 0; i < *kulen; i++)
DEBUGMSG(("generate_Ku", "%02x", Ku[i]));
DEBUGMSG(("generate_Ku", "\n"));
#endif /* NETSNMP_ENABLE_TESTING_CODE */
generate_Ku_quit:
memset(buf, 0, sizeof(buf));
#ifdef NETSNMP_USE_OPENSSL
if (ctx) {
#ifdef HAVE_EVP_MD_CTX_DESTROY
EVP_MD_CTX_destroy(ctx);
#else
EVP_MD_CTX_cleanup(ctx);
free(ctx);
#endif
}
#endif
return rval;
} /* end generate_Ku() */
/*******************************************************************-o-******
* generate_Ku
*
* Parameters:
* *hashtype MIB OID for the transform type for hashing.
* hashtype_len Length of OID value.
* *P Pre-allocated bytes of passpharase.
* pplen Length of passphrase.
* *Ku Buffer to contain Ku.
* *kulen Length of Ku buffer.
*
* Returns:
* SNMPERR_SUCCESS Success.
* SNMPERR_GENERR All errors.
*
*
* Convert a passphrase into a master user key, Ku, according to the
* algorithm given in RFC 2274 concerning the SNMPv3 User Security Model (USM)
* as follows:
*
* Expand the passphrase to fill the passphrase buffer space, if necessary,
* concatenation as many duplicates as possible of P to itself. If P is
* larger than the buffer space, truncate it to fit.
*
* Then hash the result with the given hashtype transform. Return
* the result as Ku.
*
* If successful, kulen contains the size of the hash written to Ku.
*
* NOTE Passphrases less than USM_LENGTH_P_MIN characters in length
* cause an error to be returned.
* (Punt this check to the cmdline apps? XXX)
*/
int
generate_Ku( oid *hashtype, u_int hashtype_len,
u_char *P, size_t pplen,
u_char *Ku, size_t *kulen)
#if defined(USE_INTERNAL_MD5) || defined(USE_OPENSSL)
{
int rval = SNMPERR_SUCCESS,
nbytes = USM_LENGTH_EXPANDED_PASSPHRASE;
u_int i, pindex = 0;
u_char buf[USM_LENGTH_KU_HASHBLOCK],
*bufp;
#ifdef USE_OPENSSL
EVP_MD_CTX *ctx = malloc(sizeof(EVP_MD_CTX));
#else
MDstruct MD;
#endif
/*
* Sanity check.
*/
if ( !hashtype || !P || !Ku || !kulen
|| (*kulen<=0)
|| (hashtype_len != USM_LENGTH_OID_TRANSFORM) )
{
QUITFUN(SNMPERR_GENERR, generate_Ku_quit);
}
if (pplen < USM_LENGTH_P_MIN) {
#ifdef SNMP_TESTING_CODE
snmp_log(LOG_WARNING, "Warning: passphrase chosen is below the length requiremnts of the USM.\n");
#else
snmp_set_detail("Password length too short.");
QUITFUN(SNMPERR_GENERR, generate_Ku_quit);
#endif
}
/*
* Setup for the transform type.
*/
#ifdef USE_OPENSSL
if (ISTRANSFORM(hashtype, HMACMD5Auth))
EVP_DigestInit(ctx, EVP_md5());
else if (ISTRANSFORM(hashtype, HMACSHA1Auth))
EVP_DigestInit(ctx, EVP_sha1());
else {
free(ctx);
return (SNMPERR_GENERR);
}
#else
MDbegin(&MD);
#endif /* USE_OPENSSL */
while (nbytes > 0) {
bufp = buf;
for (i = 0; i < USM_LENGTH_KU_HASHBLOCK; i++) {
*bufp++ = P[pindex++ % pplen];
}
#ifdef USE_OPENSSL
EVP_DigestUpdate(ctx, buf, USM_LENGTH_KU_HASHBLOCK);
#else
if (MDupdate(&MD, buf, USM_LENGTH_KU_HASHBLOCK*8)) {
rval = SNMPERR_USM_ENCRYPTIONERROR;
goto md5_fin;
}
#endif /* USE_OPENSSL */
nbytes -= USM_LENGTH_KU_HASHBLOCK;
}
#ifdef USE_OPENSSL
EVP_DigestFinal(ctx, (unsigned char *) Ku, (unsigned int *) kulen);
/* what about free() */
#else
if (MDupdate(&MD, buf, 0)) {
rval = SNMPERR_USM_ENCRYPTIONERROR;
goto md5_fin;
}
*kulen = sc_get_properlength(hashtype, hashtype_len);
MDget(&MD, Ku, *kulen);
md5_fin:
memset(&MD, 0, sizeof(MD));
#endif /* USE_OPENSSL */
#ifdef SNMP_TESTING_CODE
DEBUGMSGTL(("generate_Ku", "generating Ku (from %s): ", P));
for(i=0; i < *kulen; i++)
DEBUGMSG(("generate_Ku", "%02x",Ku[i]));
DEBUGMSG(("generate_Ku","\n"));
#endif /* SNMP_TESTING_CODE */
generate_Ku_quit:
memset(buf, 0, sizeof(buf));
#ifdef USE_OPENSSL
free(ctx);
#endif
return rval;
} /* end generate_Ku() */
