/*******************************************************************-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() */
int ksm_rgenerate_out_msg(struct snmp_secmod_outgoing_params *parms) { krb5_auth_context auth_context = NULL; krb5_error_code retcode; krb5_ccache cc = NULL; int retval = SNMPERR_SUCCESS; krb5_data outdata, ivector; krb5_keyblock *subkey = NULL; #ifdef MIT_NEW_CRYPTO krb5_data input; krb5_enc_data output; unsigned int numcksumtypes; krb5_cksumtype *cksumtype_array; #else /* MIT_NEW_CRYPTO */ krb5_encrypt_block eblock; #endif /* MIT_NEW_CRYPTO */ size_t blocksize, encrypted_length; unsigned char *encrypted_data = NULL; int zero = 0, i; u_char *cksum_pointer, *endp = *parms->wholeMsg; krb5_cksumtype cksumtype; krb5_checksum pdu_checksum; u_char **wholeMsg = parms->wholeMsg; size_t *offset = parms->wholeMsgOffset, seq_offset; struct ksm_secStateRef *ksm_state = (struct ksm_secStateRef *) parms->secStateRef; int rc; DEBUGMSGTL(("ksm", "Starting KSM processing\n")); outdata.length = 0; outdata.data = NULL; ivector.length = 0; ivector.data = NULL; pdu_checksum.contents = NULL; if (!ksm_state) { /* * If we don't have a ksm_state, then we're a request. Get a * credential cache and build a ap_req. */ retcode = krb5_cc_default(kcontext, &cc); if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_cc_default failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } DEBUGMSGTL(("ksm", "KSM: Set credential cache successfully\n")); /* * This seems odd, since we don't need this until later (or earlier, * depending on how you look at it), but because the most likely * errors are Kerberos at this point, I'll get this now to save * time not encoding the rest of the packet. * * Also, we need the subkey to encrypt the PDU (if required). */ retcode = krb5_mk_req(kcontext, &auth_context, AP_OPTS_MUTUAL_REQUIRED | AP_OPTS_USE_SUBKEY, (char *) service_name, parms->session->peername, NULL, cc, &outdata); if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_mk_req failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } DEBUGMSGTL(("ksm", "KSM: ticket retrieved successfully for \"%s/%s\" " "(may not be actual ticket sname)\n", service_name, parms->session->peername)); } else { /* * Grab the auth_context from our security state reference */ auth_context = ksm_state->auth_context; /* * Bundle up an AP_REP. Note that we do this only when we * have a security state reference (which means we're in an agent * and we're sending a response). */ DEBUGMSGTL(("ksm", "KSM: Starting reply processing.\n")); retcode = krb5_mk_rep(kcontext, auth_context, &outdata); if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_mk_rep failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } DEBUGMSGTL(("ksm", "KSM: Finished with krb5_mk_rep()\n")); } /* * If we have to encrypt the PDU, do that now */ if (parms->secLevel == SNMP_SEC_LEVEL_AUTHPRIV) { DEBUGMSGTL(("ksm", "KSM: Starting PDU encryption.\n")); /* * It's weird - * * If we're on the manager, it's a local subkey (because that's in * our AP_REQ) * * If we're on the agent, it's a remote subkey (because that comes * FROM the received AP_REQ). */ if (ksm_state) retcode = krb5_auth_con_getremotesubkey(kcontext, auth_context, &subkey); else retcode = krb5_auth_con_getlocalsubkey(kcontext, auth_context, &subkey); if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_auth_con_getlocalsubkey failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } /* * Note that here we need to handle different things between the * old and new crypto APIs. First, we need to get the final encrypted * length of the PDU. */ #ifdef MIT_NEW_CRYPTO retcode = krb5_c_encrypt_length(kcontext, subkey->enctype, parms->scopedPduLen, &encrypted_length); if (retcode) { DEBUGMSGTL(("ksm", "Encryption length calculation failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } #else /* MIT_NEW_CRYPTO */ krb5_use_enctype(kcontext, &eblock, subkey->enctype); retcode = krb5_process_key(kcontext, &eblock, subkey); if (retcode) { DEBUGMSGTL(("ksm", "krb5_process_key failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } encrypted_length = krb5_encrypt_size(parms->scopedPduLen, eblock.crypto_entry); #endif /* MIT_NEW_CRYPTO */ encrypted_data = malloc(encrypted_length); if (!encrypted_data) { DEBUGMSGTL(("ksm", "KSM: Unable to malloc %d bytes for encrypt " "buffer: %s\n", parms->scopedPduLen, strerror(errno))); retval = SNMPERR_MALLOC; #ifndef MIT_NEW_CRYPTO krb5_finish_key(kcontext, &eblock); #endif /* ! MIT_NEW_CRYPTO */ goto error; } /* * We need to set up a blank initialization vector for the encryption. * Use a block of all zero's (which is dependent on the block size * of the encryption method). */ #ifdef MIT_NEW_CRYPTO retcode = krb5_c_block_size(kcontext, subkey->enctype, &blocksize); if (retcode) { DEBUGMSGTL(("ksm", "Unable to determine crypto block size: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } #else /* MIT_NEW_CRYPTO */ blocksize = krb5_enctype_array[subkey->enctype]->system->block_length; #endif /* MIT_NEW_CRYPTO */ ivector.data = malloc(blocksize); if (!ivector.data) { DEBUGMSGTL(("ksm", "Unable to allocate %d bytes for ivector\n", blocksize)); retval = SNMPERR_MALLOC; goto error; } ivector.length = blocksize; memset(ivector.data, 0, blocksize); /* * Finally! Do the encryption! */ #ifdef MIT_NEW_CRYPTO input.data = (char *) parms->scopedPdu; input.length = parms->scopedPduLen; output.ciphertext.data = (char *) encrypted_data; output.ciphertext.length = encrypted_length; retcode = krb5_c_encrypt(kcontext, subkey, KSM_KEY_USAGE_ENCRYPTION, &ivector, &input, &output); #else /* MIT_NEW_CRYPTO */ retcode = krb5_encrypt(kcontext, (krb5_pointer) parms->scopedPdu, (krb5_pointer) encrypted_data, parms->scopedPduLen, &eblock, ivector.data); krb5_finish_key(kcontext, &eblock); #endif /* MIT_NEW_CRYPTO */ if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_encrypt failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } *offset = 0; rc = asn_realloc_rbuild_string(wholeMsg, parms->wholeMsgLen, offset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), encrypted_data, encrypted_length); if (rc == 0) { DEBUGMSGTL(("ksm", "Building encrypted payload failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } DEBUGMSGTL(("ksm", "KSM: Encryption complete.\n")); } else { /* * Plaintext PDU (not encrypted) */ if (*parms->wholeMsgLen < parms->scopedPduLen) { DEBUGMSGTL(("ksm", "Not enough room for plaintext PDU.\n")); retval = SNMPERR_TOO_LONG; goto error; } } /* * Start encoding the msgSecurityParameters * * For now, use 0 for the response hint */ DEBUGMSGTL(("ksm", "KSM: scopedPdu added to payload\n")); seq_offset = *offset; rc = asn_realloc_rbuild_int(wholeMsg, parms->wholeMsgLen, offset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_INTEGER), (long *) &zero, sizeof(zero)); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm security parameters failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } rc = asn_realloc_rbuild_string(wholeMsg, parms->wholeMsgLen, offset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), (u_char *) outdata.data, outdata.length); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm AP_REQ failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } /* * Now, we need to pick the "right" checksum algorithm. For old * crypto, just pick CKSUMTYPE_RSA_MD5_DES; for new crypto, pick * one of the "approved" ones. */ #ifdef MIT_NEW_CRYPTO retcode = krb5_c_keyed_checksum_types(kcontext, subkey->enctype, &numcksumtypes, &cksumtype_array); if (retcode) { DEBUGMSGTL(("ksm", "Unable to find appropriate keyed checksum: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } if (numcksumtypes <= 0) { DEBUGMSGTL(("ksm", "We received a list of zero cksumtypes for this " "enctype (%d)\n", subkey->enctype)); snmp_set_detail("No valid checksum type for this encryption type"); retval = SNMPERR_KRB5; goto error; } /* * It's not clear to me from the API which checksum you're supposed * to support, so I'm taking a guess at the first one */ cksumtype = cksumtype_array[0]; krb5_free_cksumtypes(kcontext, cksumtype_array); DEBUGMSGTL(("ksm", "KSM: Choosing checksum type of %d (subkey type " "of %d)\n", cksumtype, subkey->enctype)); retcode = krb5_c_checksum_length(kcontext, cksumtype, &blocksize); if (retcode) { DEBUGMSGTL(("ksm", "Unable to determine checksum length: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } pdu_checksum.length = blocksize; #else /* MIT_NEW_CRYPTO */ if (ksm_state) cksumtype = ksm_state->cksumtype; else cksumtype = CKSUMTYPE_RSA_MD5_DES; if (!is_keyed_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a keyed checksum\n", cksumtype)); snmp_set_detail("Checksum is not a keyed checksum"); retval = SNMPERR_KRB5; goto error; } if (!is_coll_proof_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a collision-proof " "checksum\n", cksumtype)); snmp_set_detail("Checksum is not a collision-proof checksum"); retval = SNMPERR_KRB5; goto error; } pdu_checksum.length = krb5_checksum_size(kcontext, cksumtype); pdu_checksum.checksum_type = cksumtype; #endif /* MIT_NEW_CRYPTO */ /* * Note that here, we're just leaving blank space for the checksum; * we remember where that is, and we'll fill it in later. */ *offset += pdu_checksum.length; memset(*wholeMsg + *parms->wholeMsgLen - *offset, 0, pdu_checksum.length); cksum_pointer = *wholeMsg + *parms->wholeMsgLen - *offset; rc = asn_realloc_rbuild_header(wholeMsg, parms->wholeMsgLen, parms->wholeMsgOffset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), pdu_checksum.length); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm security parameters failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } rc = asn_realloc_rbuild_int(wholeMsg, parms->wholeMsgLen, parms->wholeMsgOffset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), (long *) &cksumtype, sizeof(cksumtype)); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm security parameters failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } rc = asn_realloc_rbuild_sequence(wholeMsg, parms->wholeMsgLen, parms->wholeMsgOffset, 1, (u_char) (ASN_SEQUENCE | ASN_CONSTRUCTOR), *offset - seq_offset); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm security parameters failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } rc = asn_realloc_rbuild_header(wholeMsg, parms->wholeMsgLen, parms->wholeMsgOffset, 1, (u_char) (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), *offset - seq_offset); if (rc == 0) { DEBUGMSGTL(("ksm", "Building ksm security parameters failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } DEBUGMSGTL(("ksm", "KSM: Security parameter encoding completed\n")); /* * We're done with the KSM security parameters - now we do the global * header and wrap up the whole PDU. */ if (*parms->wholeMsgLen < parms->globalDataLen) { DEBUGMSGTL(("ksm", "Building global data failed.\n")); retval = SNMPERR_TOO_LONG; goto error; } *offset += parms->globalDataLen; memcpy(*wholeMsg + *parms->wholeMsgLen - *offset, parms->globalData, parms->globalDataLen); rc = asn_realloc_rbuild_sequence(wholeMsg, parms->wholeMsgLen, offset, 1, (u_char) (ASN_SEQUENCE | ASN_CONSTRUCTOR), *offset); if (rc == 0) { DEBUGMSGTL(("ksm", "Building master packet sequence.\n")); retval = SNMPERR_TOO_LONG; goto error; } DEBUGMSGTL(("ksm", "KSM: PDU master packet encoding complete.\n")); /* * Now we need to checksum the entire PDU (since it's built). */ pdu_checksum.contents = malloc(pdu_checksum.length); if (!pdu_checksum.contents) { DEBUGMSGTL(("ksm", "Unable to malloc %d bytes for checksum\n", pdu_checksum.length)); retval = SNMPERR_MALLOC; goto error; } /* * If we didn't encrypt the packet, we haven't yet got the subkey. * Get that now. */ if (!subkey) { if (ksm_state) retcode = krb5_auth_con_getremotesubkey(kcontext, auth_context, &subkey); else retcode = krb5_auth_con_getlocalsubkey(kcontext, auth_context, &subkey); if (retcode) { DEBUGMSGTL(("ksm", "krb5_auth_con_getlocalsubkey failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } } #ifdef MIT_NEW_CRYPTO input.data = (char *) (*wholeMsg + *parms->wholeMsgLen - *offset); input.length = *offset; retcode = krb5_c_make_checksum(kcontext, cksumtype, subkey, KSM_KEY_USAGE_CHECKSUM, &input, &pdu_checksum); #else /* MIT_NEW_CRYPTO */ retcode = krb5_calculate_checksum(kcontext, cksumtype, *wholeMsg + *parms->wholeMsgLen - *offset, *offset, (krb5_pointer) subkey->contents, subkey->length, &pdu_checksum); #endif /* MIT_NEW_CRYPTO */ if (retcode) { DEBUGMSGTL(("ksm", "Calculate checksum failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } DEBUGMSGTL(("ksm", "KSM: Checksum calculation complete.\n")); memcpy(cksum_pointer, pdu_checksum.contents, pdu_checksum.length); DEBUGMSGTL(("ksm", "KSM: Writing checksum of %d bytes at offset %d\n", pdu_checksum.length, cksum_pointer - (*wholeMsg + 1))); DEBUGMSGTL(("ksm", "KSM: Checksum:")); for (i = 0; i < pdu_checksum.length; i++) DEBUGMSG(("ksm", " %02x", (unsigned int) pdu_checksum.contents[i])); DEBUGMSG(("ksm", "\n")); /* * If we're _not_ called as part of a response (null ksm_state), * then save the auth_context for later using our cache routines. */ if (!ksm_state) { if ((retval = ksm_insert_cache(parms->pdu->msgid, auth_context, (u_char *) parms->secName, parms->secNameLen)) != SNMPERR_SUCCESS) goto error; auth_context = NULL; } DEBUGMSGTL(("ksm", "KSM processing complete!\n")); error: if (pdu_checksum.contents) #ifdef MIT_NEW_CRYPTO krb5_free_checksum_contents(kcontext, &pdu_checksum); #else /* MIT_NEW_CRYPTO */ free(pdu_checksum.contents); #endif /* MIT_NEW_CRYPTO */ if (ivector.data) free(ivector.data); if (subkey) krb5_free_keyblock(kcontext, subkey); if (encrypted_data) free(encrypted_data); if (cc) krb5_cc_close(kcontext, cc); if (auth_context && !ksm_state) krb5_auth_con_free(kcontext, auth_context); return retval; }
int snmp_sess_synch_response(void *sessp, netsnmp_pdu *pdu, netsnmp_pdu **response) { netsnmp_session *ss; struct synch_state lstate, *state; snmp_callback cbsav; void *cbmagsav; int numfds, count; fd_set fdset; struct timeval timeout, *tvp; int block; ss = snmp_sess_session(sessp); memset((void *) &lstate, 0, sizeof(lstate)); state = &lstate; cbsav = ss->callback; cbmagsav = ss->callback_magic; ss->callback = snmp_synch_input; ss->callback_magic = (void *) state; if ((state->reqid = snmp_sess_send(sessp, pdu)) == 0) { snmp_free_pdu(pdu); state->status = STAT_ERROR; } else state->waiting = 1; while (state->waiting) { numfds = 0; FD_ZERO(&fdset); block = SNMPBLOCK; tvp = &timeout; timerclear(tvp); snmp_sess_select_info(sessp, &numfds, &fdset, tvp, &block); if (block == 1) tvp = NULL; /* block without timeout */ count = select(numfds, &fdset, 0, 0, tvp); if (count > 0) { snmp_sess_read(sessp, &fdset); } else switch (count) { case 0: snmp_sess_timeout(sessp); break; case -1: if (errno == EINTR) { continue; } else { snmp_errno = SNMPERR_GENERR; /* * CAUTION! if another thread closed the socket(s) * waited on here, the session structure was freed. * It would be nice, but we can't rely on the pointer. * ss->s_snmp_errno = SNMPERR_GENERR; * ss->s_errno = errno; */ snmp_set_detail(strerror(errno)); } /* * FALLTHRU */ default: state->status = STAT_ERROR; state->waiting = 0; } } *response = state->pdu; ss->callback = cbsav; ss->callback_magic = cbmagsav; return state->status; }
int ksm_process_in_msg(struct snmp_secmod_incoming_params *parms) { long temp; krb5_cksumtype cksumtype; krb5_auth_context auth_context = NULL; krb5_error_code retcode; krb5_checksum checksum; krb5_data ap_req, ivector; krb5_flags flags; krb5_keyblock *subkey = NULL; #ifdef MIT_NEW_CRYPTO krb5_data input, output; krb5_boolean valid; krb5_enc_data in_crypt; #else /* MIT_NEW_CRYPTO */ krb5_encrypt_block eblock; #endif /* MIT_NEW_CRYPTO */ krb5_ticket *ticket = NULL; int retval = SNMPERR_SUCCESS, response = 0; size_t length = parms->wholeMsgLen - (u_int) (parms->secParams - parms->wholeMsg); u_char *current = parms->secParams, type; size_t cksumlength, blocksize; long hint; char *cname; struct ksm_secStateRef *ksm_state; struct ksm_cache_entry *entry; DEBUGMSGTL(("ksm", "Processing has begun\n")); checksum.contents = NULL; ap_req.data = NULL; ivector.length = 0; ivector.data = NULL; /* * First, parse the security parameters (because we need the subkey inside * of the ticket to do anything */ if ((current = asn_parse_sequence(current, &length, &type, (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), "ksm first octet")) == NULL) { DEBUGMSGTL(("ksm", "Initial security paramter parsing failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } if ((current = asn_parse_sequence(current, &length, &type, (ASN_SEQUENCE | ASN_CONSTRUCTOR), "ksm sequence")) == NULL) { DEBUGMSGTL(("ksm", "Security parameter sequence parsing failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } if ((current = asn_parse_int(current, &length, &type, &temp, sizeof(temp))) == NULL) { DEBUGMSGTL(("ksm", "Security parameter checksum type parsing" "failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } cksumtype = temp; #ifdef MIT_NEW_CRYPTO if (!krb5_c_valid_cksumtype(cksumtype)) { DEBUGMSGTL(("ksm", "Invalid checksum type (%d)\n", cksumtype)); retval = SNMPERR_KRB5; snmp_set_detail("Invalid checksum type"); goto error; } if (!krb5_c_is_keyed_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a keyed checksum\n", cksumtype)); snmp_set_detail("Checksum is not a keyed checksum"); retval = SNMPERR_KRB5; goto error; } if (!krb5_c_is_coll_proof_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a collision-proof " "checksum\n", cksumtype)); snmp_set_detail("Checksum is not a collision-proof checksum"); retval = SNMPERR_KRB5; goto error; } #else /* ! MIT_NEW_CRYPTO */ if (!valid_cksumtype(cksumtype)) { DEBUGMSGTL(("ksm", "Invalid checksum type (%d)\n", cksumtype)); retval = SNMPERR_KRB5; snmp_set_detail("Invalid checksum type"); goto error; } if (!is_keyed_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a keyed checksum\n", cksumtype)); snmp_set_detail("Checksum is not a keyed checksum"); retval = SNMPERR_KRB5; goto error; } if (!is_coll_proof_cksum(cksumtype)) { DEBUGMSGTL(("ksm", "Checksum type %d is not a collision-proof " "checksum\n", cksumtype)); snmp_set_detail("Checksum is not a collision-proof checksum"); retval = SNMPERR_KRB5; goto error; } #endif /* MIT_NEW_CRYPTO */ checksum.checksum_type = cksumtype; cksumlength = length; if ((current = asn_parse_sequence(current, &cksumlength, &type, (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), "ksm checksum")) == NULL) { DEBUGMSGTL(("ksm", "Security parameter checksum parsing failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } checksum.contents = malloc(cksumlength); if (!checksum.contents) { DEBUGMSGTL(("ksm", "Unable to malloc %d bytes for checksum.\n", cksumlength)); retval = SNMPERR_MALLOC; goto error; } memcpy(checksum.contents, current, cksumlength); checksum.length = cksumlength; checksum.checksum_type = cksumtype; /* * Zero out the checksum so the validation works correctly */ memset(current, 0, cksumlength); current += cksumlength; length = parms->wholeMsgLen - (u_int) (current - parms->wholeMsg); if ((current = asn_parse_sequence(current, &length, &type, (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), "ksm ap_req")) == NULL) { DEBUGMSGTL(("ksm", "KSM security parameter AP_REQ/REP parsing " "failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } ap_req.length = length; ap_req.data = malloc(length); if (!ap_req.data) { DEBUGMSGTL(("ksm", "KSM unable to malloc %d bytes for AP_REQ/REP.\n", length)); retval = SNMPERR_MALLOC; goto error; } memcpy(ap_req.data, current, length); current += length; length = parms->wholeMsgLen - (u_int) (current - parms->wholeMsg); if ((current = asn_parse_int(current, &length, &type, &hint, sizeof(hint))) == NULL) { DEBUGMSGTL(("ksm", "KSM security parameter hint parsing failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } /* * Okay! We've got it all! Now try decoding the damn ticket. * * But of course there's a WRINKLE! We need to figure out if we're * processing a AP_REQ or an AP_REP. How do we do that? We're going * to cheat, and look at the first couple of bytes (which is what * the Kerberos library routines do anyway). * * If there are ever new Kerberos message formats, we'll need to fix * this here. * * If it's a _response_, then we need to get the auth_context * from our cache. */ if (ap_req.length && (ap_req.data[0] == 0x6e || ap_req.data[0] == 0x4e)) { /* * We need to initalize the authorization context, and set the * replay cache in it (and initialize the replay cache if we * haven't already */ retcode = krb5_auth_con_init(kcontext, &auth_context); if (retcode) { DEBUGMSGTL(("ksm", "krb5_auth_con_init failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } if (!rcache) { krb5_data server; server.data = "host"; server.length = strlen(server.data); retcode = krb5_get_server_rcache(kcontext, &server, &rcache); if (retcode) { DEBUGMSGTL(("ksm", "krb5_get_server_rcache failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } } retcode = krb5_auth_con_setrcache(kcontext, auth_context, rcache); if (retcode) { DEBUGMSGTL(("ksm", "krb5_auth_con_setrcache failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } retcode = krb5_rd_req(kcontext, &auth_context, &ap_req, NULL, keytab, &flags, &ticket); krb5_auth_con_setrcache(kcontext, auth_context, NULL); if (retcode) { DEBUGMSGTL(("ksm", "krb5_rd_req() failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } retcode = krb5_unparse_name(kcontext, ticket->enc_part2->client, &cname); if (retcode == 0) { DEBUGMSGTL(("ksm", "KSM authenticated principal name: %s\n", cname)); free(cname); } /* * Check to make sure AP_OPTS_MUTUAL_REQUIRED was set */ if (!(flags & AP_OPTS_MUTUAL_REQUIRED)) { DEBUGMSGTL(("ksm", "KSM MUTUAL_REQUIRED not set in request!\n")); retval = SNMPERR_KRB5; snmp_set_detail("MUTUAL_REQUIRED not set in message"); goto error; } retcode = krb5_auth_con_getremotesubkey(kcontext, auth_context, &subkey); if (retcode) { DEBUGMSGTL(("ksm", "KSM remote subkey retrieval failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } } else if (ap_req.length && (ap_req.data[0] == 0x6f || ap_req.data[0] == 0x4f)) { /* * Looks like a response; let's see if we've got that auth_context * in our cache. */ krb5_ap_rep_enc_part *repl = NULL; response = 1; entry = ksm_get_cache(parms->pdu->msgid); if (!entry) { DEBUGMSGTL(("ksm", "KSM: Unable to find auth_context for PDU with " "message ID of %ld\n", parms->pdu->msgid)); retval = SNMPERR_KRB5; goto error; } auth_context = entry->auth_context; /* * In that case, let's call the rd_rep function */ retcode = krb5_rd_rep(kcontext, auth_context, &ap_req, &repl); if (repl) krb5_free_ap_rep_enc_part(kcontext, repl); if (retcode) { DEBUGMSGTL(("ksm", "KSM: krb5_rd_rep() failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; goto error; } DEBUGMSGTL(("ksm", "KSM: krb5_rd_rep() decoded successfully.\n")); retcode = krb5_auth_con_getlocalsubkey(kcontext, auth_context, &subkey); if (retcode) { DEBUGMSGTL(("ksm", "Unable to retrieve local subkey: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail("Unable to retrieve local subkey"); goto error; } } else { DEBUGMSGTL(("ksm", "Unknown Kerberos message type (%02x)\n", ap_req.data[0])); retval = SNMPERR_KRB5; snmp_set_detail("Unknown Kerberos message type"); goto error; } #ifdef MIT_NEW_CRYPTO input.data = (char *) parms->wholeMsg; input.length = parms->wholeMsgLen; retcode = krb5_c_verify_checksum(kcontext, subkey, KSM_KEY_USAGE_CHECKSUM, &input, &checksum, &valid); #else /* MIT_NEW_CRYPTO */ retcode = krb5_verify_checksum(kcontext, cksumtype, &checksum, parms->wholeMsg, parms->wholeMsgLen, (krb5_pointer) subkey->contents, subkey->length); #endif /* MIT_NEW_CRYPTO */ if (retcode) { DEBUGMSGTL(("ksm", "KSM checksum verification failed: %s\n", error_message(retcode))); retval = SNMPERR_KRB5; snmp_set_detail(error_message(retcode)); goto error; } /* * Don't ask me why they didn't simply return an error, but we have * to check to see if "valid" is false. */ #ifdef MIT_NEW_CRYPTO if (!valid) { DEBUGMSGTL(("ksm", "Computed checksum did not match supplied " "checksum!\n")); retval = SNMPERR_KRB5; snmp_set_detail ("Computed checksum did not match supplied checksum"); goto error; } #endif /* MIT_NEW_CRYPTO */ /* * Handle an encrypted PDU. Note that it's an OCTET_STRING of the * output of whatever Kerberos cryptosystem you're using (defined by * the encryption type). Note that this is NOT the EncryptedData * sequence - it's what goes in the "cipher" field of EncryptedData. */ if (parms->secLevel == SNMP_SEC_LEVEL_AUTHPRIV) { if ((current = asn_parse_sequence(current, &length, &type, (ASN_UNIVERSAL | ASN_PRIMITIVE | ASN_OCTET_STR), "ksm pdu")) == NULL) { DEBUGMSGTL(("ksm", "KSM sPDU octet decoding failed\n")); retval = SNMPERR_ASN_PARSE_ERR; goto error; } /* * The PDU is now pointed at by "current", and the length is in * "length". */ DEBUGMSGTL(("ksm", "KSM starting sPDU decode\n")); /* * We need to set up a blank initialization vector for the decryption. * Use a block of all zero's (which is dependent on the block size * of the encryption method). */ #ifdef MIT_NEW_CRYPTO retcode = krb5_c_block_size(kcontext, subkey->enctype, &blocksize); if (retcode) { DEBUGMSGTL(("ksm", "Unable to determine crypto block size: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } #else /* MIT_NEW_CRYPTO */ blocksize = krb5_enctype_array[subkey->enctype]->system->block_length; #endif /* MIT_NEW_CRYPTO */ ivector.data = malloc(blocksize); if (!ivector.data) { DEBUGMSGTL(("ksm", "Unable to allocate %d bytes for ivector\n", blocksize)); retval = SNMPERR_MALLOC; goto error; } ivector.length = blocksize; memset(ivector.data, 0, blocksize); #ifndef MIT_NEW_CRYPTO krb5_use_enctype(kcontext, &eblock, subkey->enctype); retcode = krb5_process_key(kcontext, &eblock, subkey); if (retcode) { DEBUGMSGTL(("ksm", "KSM key post-processing failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } #endif /* !MIT_NEW_CRYPTO */ if (length > *parms->scopedPduLen) { DEBUGMSGTL(("ksm", "KSM not enough room - have %d bytes to " "decrypt but only %d bytes available\n", length, *parms->scopedPduLen)); retval = SNMPERR_TOO_LONG; #ifndef MIT_NEW_CRYPTO krb5_finish_key(kcontext, &eblock); #endif /* ! MIT_NEW_CRYPTO */ goto error; } #ifdef MIT_NEW_CRYPTO in_crypt.ciphertext.data = (char *) current; in_crypt.ciphertext.length = length; in_crypt.enctype = subkey->enctype; output.data = (char *) *parms->scopedPdu; output.length = *parms->scopedPduLen; retcode = krb5_c_decrypt(kcontext, subkey, KSM_KEY_USAGE_ENCRYPTION, &ivector, &in_crypt, &output); #else /* MIT_NEW_CRYPTO */ retcode = krb5_decrypt(kcontext, (krb5_pointer) current, *parms->scopedPdu, length, &eblock, ivector.data); krb5_finish_key(kcontext, &eblock); #endif /* MIT_NEW_CRYPTO */ if (retcode) { DEBUGMSGTL(("ksm", "Decryption failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } *parms->scopedPduLen = length; } else { /* * Clear PDU */ *parms->scopedPdu = current; *parms->scopedPduLen = parms->wholeMsgLen - (current - parms->wholeMsg); } /* * A HUGE GROSS HACK */ *parms->maxSizeResponse = parms->maxMsgSize - 200; DEBUGMSGTL(("ksm", "KSM processing complete\n")); /* * Set the secName to the right value (a hack for now). But that's * only used for when we're processing a request, not a response. */ if (!response) { retcode = krb5_unparse_name(kcontext, ticket->enc_part2->client, &cname); if (retcode) { DEBUGMSGTL(("ksm", "KSM krb5_unparse_name failed: %s\n", error_message(retcode))); snmp_set_detail(error_message(retcode)); retval = SNMPERR_KRB5; goto error; } if (strlen(cname) > *parms->secNameLen + 1) { DEBUGMSGTL(("ksm", "KSM: Principal length (%d) is too long (%d)\n", strlen(cname), parms->secNameLen)); retval = SNMPERR_TOO_LONG; free(cname); goto error; } strcpy(parms->secName, cname); *parms->secNameLen = strlen(cname); free(cname); /* * Also, if we're not a response, keep around our auth_context so we * can encode the reply message correctly */ ksm_state = SNMP_MALLOC_STRUCT(ksm_secStateRef); if (!ksm_state) { DEBUGMSGTL(("ksm", "KSM unable to malloc memory for " "ksm_secStateRef\n")); retval = SNMPERR_MALLOC; goto error; } ksm_state->auth_context = auth_context; auth_context = NULL; ksm_state->cksumtype = cksumtype; *parms->secStateRef = ksm_state; } else { /* * We _still_ have to set the secName in process_in_msg(). Do * that now with what we were passed in before (we cached it, * remember?) */ memcpy(parms->secName, entry->secName, entry->secNameLen); *parms->secNameLen = entry->secNameLen; } /* * Just in case */ parms->secEngineID = (u_char *) ""; *parms->secEngineIDLen = 0; auth_context = NULL; /* So we don't try to free it on success */ error: if (retval == SNMPERR_ASN_PARSE_ERR && snmp_increment_statistic(STAT_SNMPINASNPARSEERRS) == 0) DEBUGMSGTL(("ksm", "Failed to increment statistics.\n")); if (subkey) krb5_free_keyblock(kcontext, subkey); if (checksum.contents) free(checksum.contents); if (ivector.data) free(ivector.data); if (ticket) krb5_free_ticket(kcontext, ticket); if (!response && auth_context) krb5_auth_con_free(kcontext, auth_context); if (ap_req.data) free(ap_req.data); return retval; }