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Partly apply Elias Oenal's SNMP V3 patch. There is more to come, the work is incomplete at the moment and does not compile when LWIP_SNMP_V3 is enabled.

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This commit is contained in:
Dirk Ziegelmeier 2016-03-29 10:16:17 +02:00
parent 6f43057662
commit d0c3baf340
4 changed files with 503 additions and 11 deletions
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3
src/apps/snmp/snmp_asn1.h
View File

@ -5,6 +5,7 @@
/*
* Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
* Copyright (c) 2016 Elias Oenal.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
@ -31,6 +32,7 @@
*
* Author: Christiaan Simons <christiaan.simons@axon.tv>
* Martin Hentschel <info@cl-soft.de>
* Elias Oenal <lwip@eliasoenal.com>
*/
#ifndef LWIP_HDR_APPS_SNMP_ASN1_H
@ -73,6 +75,7 @@ struct snmp_asn1_tlv
u8_t length_len; /* indicates how many bytes are required to encode the 'value_len' field */
u16_t value_len; /* encoded length of the value */
};
#define SNMP_ASN1_TLV_HDR_LENGTH(tlv) ((tlv).type_len + (tlv).length_len)
#define SNMP_ASN1_TLV_LENGTH(tlv) ((tlv).type_len + (tlv).length_len + (tlv).value_len)
#define SNMP_ASN1_SET_TLV_PARAMS(tlv, type_, length_len_, value_len_) do { (tlv).type = (type_); (tlv).type_len = 0; (tlv).length_len = (length_len_); (tlv).value_len = (value_len_); } while (0);

465
src/apps/snmp/snmp_msg.c
View File

@ -5,6 +5,7 @@
/*
* Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
* Copyright (c) 2016 Elias Oenal.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
@ -31,6 +32,7 @@
*
* Author: Christiaan Simons <christiaan.simons@axon.tv>
* Martin Hentschel <info@cl-soft.de>
* Elias Oenal <lwip@eliasoenal.com>
*/
#include "lwip/apps/snmp_opts.h"
@ -45,6 +47,13 @@
#include <string.h>
#if LWIP_SNMP_V3
#include "snmpv3.h"
#ifdef LWIP_SNMPV3_INCLUDE_ENGINE
#include LWIP_SNMPV3_INCLUDE_ENGINE
#endif
#endif
/* public (non-static) constants */
/** SNMP community string */
const char *snmp_community = SNMP_COMMUNITY;
@ -256,7 +265,7 @@ snmp_process_varbind(struct snmp_request *request, struct snmp_varbind *vb, u8_t
if (request->error_status != SNMP_ERR_NOERROR)
{
if (request->error_status >= SNMP_VARBIND_EXCEPTION_OFFSET) {
if (request->version == SNMP_VERSION_2c) {
if ((request->version == SNMP_VERSION_2c) || request->version == SNMP_VERSION_3) {
/* in SNMP v2c a varbind related exception is stored in varbind and not in frame header */
vb->type = (SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_CLASS_CONTEXT | (request->error_status & SNMP_VARBIND_EXCEPTION_MASK));
vb->value_len = 0;
@ -608,13 +617,225 @@ snmp_parse_inbound_frame(struct snmp_request *request)
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &s32_value));
if ((s32_value != SNMP_VERSION_1) && (s32_value != SNMP_VERSION_2c)) {
if ((s32_value != SNMP_VERSION_1) &&
(s32_value != SNMP_VERSION_2c)
#if LWIP_SNMP_V3
&& (s32_value != SNMP_VERSION_3)
#endif
)
{
/* unsupported SNMP version */
snmp_stats.inbadversions++;
return ERR_ARG;
}
request->version = (u8_t)s32_value;
#if LWIP_SNMP_V3
if (request->version == SNMP_VERSION_3) {
u16_t u16_value;
/* SNMPv3 doesn't use communities */
/* TODO: Differentiate read/write access */
strcpy((char*)request->community, snmp_community);
request->community_strlen = strlen(snmp_community);
/* RFC3414 globalData */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_SEQUENCE);
parent_tlv_value_len -= SNMP_ASN1_TLV_HDR_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
/* decode msgID */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_INTEGER);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &s32_value));
request->msg_id = s32_value;
/* decode msgMaxSize */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_INTEGER);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &s32_value));
request->msg_max_size = s32_value;
/* decode msgFlags */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &s32_value));
request->msg_flags = s32_value;
/* decode msgSecurityModel */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_INTEGER);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &s32_value));
request->msg_security_model = s32_value;
/* RFC3414 msgSecurityParameters
* The User-based Security Model defines the contents of the OCTET
* STRING as a SEQUENCE.
*
* We skip the protective dummy OCTET STRING header
* to access the SEQUENCE header.
*/
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_HDR_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
/* msgSecurityParameters SEQUENCE header */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_SEQUENCE);
parent_tlv_value_len -= SNMP_ASN1_TLV_HDR_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
/* decode msgAuthoritativeEngineID */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->msg_authoritative_engine_id,
&u16_value, SNMP_V3_MAX_ENGINE_ID_LENGTH));
request->msg_authoritative_engine_id_len = u16_value;
/* msgAuthoritativeEngineBoots */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_INTEGER);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &request->msg_authoritative_engine_boots));
/* msgAuthoritativeEngineTime */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_INTEGER);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_s32t(&pbuf_stream, tlv.value_len, &request->msg_authoritative_engine_time));
/* TODO: Implement time window checking */
/* msgUserName */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->msg_user_name,
&u16_value, SNMP_V3_MAX_USER_LENGTH));
request->msg_user_name_len = u16_value;
/* TODO: Implement unknown user error response */
IF_PARSE_EXEC(LWIP_SNMPV3_GET_USER(request->msg_user_name, NULL, NULL, NULL, NULL));
/* msgAuthenticationParameters */
memset(request->msg_authentication_parameters, 0, SNMP_V3_MAX_AUTH_PARAM_LENGTH);
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
/* Remember position */
u16_t inbound_msgAuthenticationParameters_offset = pbuf_stream.offset;
LWIP_UNUSED_ARG(inbound_msgAuthenticationParameters_offset);
/* Read auth parameters */
IF_PARSE_ASSERT(tlv.value_len <= SNMP_V3_MAX_AUTH_PARAM_LENGTH);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->msg_authentication_parameters,
&u16_value, tlv.value_len));
#ifdef LWIP_SNMP_V3_CRYPTO
if (request->msg_flags & SNMP_V3_AUTH_FLAG) {
/* Rewind stream */
IF_PARSE_EXEC(snmp_pbuf_stream_init(&pbuf_stream, request->inbound_pbuf, 0, request->inbound_pbuf->tot_len));
IF_PARSE_EXEC(snmp_pbuf_stream_seek_abs(&pbuf_stream, inbound_msgAuthenticationParameters_offset));
/* Set auth parameters to zero for verification */
const u8_t zero_arr[SNMP_V3_MAX_AUTH_PARAM_LENGTH] = { 0 };
IF_PARSE_EXEC(snmp_asn1_enc_raw(&pbuf_stream, zero_arr, tlv.value_len));
/* Verify authentication */
u8_t* key;
u8_t algo;
u8_t hmac[20];
struct snmp_pbuf_stream auth_stream;
IF_PARSE_EXEC(snmp_pbuf_stream_init(&auth_stream, request->inbound_pbuf, 0, request->inbound_pbuf->tot_len));
IF_PARSE_EXEC(LWIP_SNMPV3_GET_USER(request->msg_user_name, &algo, &key, NULL, NULL));
IF_PARSE_EXEC(snmpv3_auth(&auth_stream, request->inbound_pbuf->tot_len, key, algo, hmac));
/* TODO: Implement error response */
IF_PARSE_EXEC(memcmp(request->msg_authentication_parameters, hmac, SNMP_V3_MAX_AUTH_PARAM_LENGTH));
}
#else
/* Ungraceful exit if we encounter cryptography and don't support it.
* TODO: Implement error response
*/
IF_PARSE_ASSERT(!(request->msg_flags & (SNMP_V3_AUTH_FLAG | SNMP_V3_PRIV_FLAG)));
#endif
/* msgPrivacyParameters */
memset(request->msg_privacy_parameters, 0, SNMP_V3_MAX_PRIV_PARAM_LENGTH);
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->msg_privacy_parameters,
&u16_value, SNMP_V3_MAX_PRIV_PARAM_LENGTH));
#ifdef LWIP_SNMP_V3_CRYPTO
/* Decrypt message */
if (request->msg_flags & SNMP_V3_PRIV_FLAG) {
u8_t* key;
u8_t algo;
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_HDR_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(LWIP_SNMPV3_GET_USER(request->msg_user_name, NULL, NULL, &algo, &key));
IF_PARSE_EXEC(snmpv3_crypt(&pbuf_stream, tlv.value_len, key,
request->msg_privacy_parameters, request->msg_authoritative_engine_boots,
request->msg_authoritative_engine_time, algo, SNMP_V3_PRIV_MODE_DECRYPT));
}
#endif
/* Scoped PDU
* Encryption context
*/
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_SEQUENCE);
parent_tlv_value_len -= SNMP_ASN1_TLV_HDR_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
/* contextEngineID */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->context_engine_id,
&u16_value, SNMP_V3_MAX_ENGINE_ID_LENGTH));
request->context_engine_id_len = u16_value;
/* contextName */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
parent_tlv_value_len -= SNMP_ASN1_TLV_LENGTH(tlv);
IF_PARSE_ASSERT(parent_tlv_value_len > 0);
IF_PARSE_EXEC(snmp_asn1_dec_raw(&pbuf_stream, tlv.value_len, request->context_name,
&u16_value, SNMP_V3_MAX_ENGINE_ID_LENGTH));
request->context_name_len = u16_value;
} else
#endif
{
/* decode community */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.type == SNMP_ASN1_TYPE_OCTET_STRING);
@ -631,10 +852,12 @@ snmp_parse_inbound_frame(struct snmp_request *request)
}
/* add zero terminator */
request->community[request->community_strlen] = 0;
}
/* decode PDU type (next container level) */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT(tlv.value_len == pbuf_stream.length);
IF_PARSE_ASSERT(tlv.value_len <= pbuf_stream.length);
request->inbound_padding_len = pbuf_stream.length - tlv.value_len;
parent_tlv_value_len = tlv.value_len;
/* validate PDU type */
@ -737,10 +960,10 @@ snmp_parse_inbound_frame(struct snmp_request *request)
/* decode varbind-list type (next container level) */
IF_PARSE_EXEC(snmp_asn1_dec_tlv(&pbuf_stream, &tlv));
IF_PARSE_ASSERT((tlv.type == SNMP_ASN1_TYPE_SEQUENCE) && (tlv.value_len == pbuf_stream.length));
IF_PARSE_ASSERT((tlv.type == SNMP_ASN1_TYPE_SEQUENCE) && (tlv.value_len <= pbuf_stream.length));
request->inbound_varbind_offset = pbuf_stream.offset;
request->inbound_varbind_len = pbuf_stream.length;
request->inbound_varbind_len = pbuf_stream.length - request->inbound_padding_len;
snmp_vb_enumerator_init(&(request->inbound_varbind_enumerator), request->inbound_pbuf, request->inbound_varbind_offset, request->inbound_varbind_len);
return ERR_OK;
@ -772,10 +995,143 @@ snmp_prepare_outbound_frame(struct snmp_request *request)
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
OF_BUILD_EXEC( snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->version) );
#if LWIP_SNMP_V3
if (request->version < SNMP_VERSION_3) {
#endif
/* community */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->community_strlen);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
OF_BUILD_EXEC( snmp_asn1_enc_raw(pbuf_stream, request->community, request->community_strlen) );
#if LWIP_SNMP_V3
} else {
/* globalData */
request->outbound_msg_global_data_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 1, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
/* msgID */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 1);
snmp_asn1_enc_s32t_cnt(request->msg_id, &tlv.value_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->msg_id));
/* msgMaxSize */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 1);
snmp_asn1_enc_s32t_cnt(request->msg_max_size, &tlv.value_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->msg_max_size));
/* msgFlags */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, 1);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, &request->msg_flags, 1));
/* msgSecurityModel */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 1);
snmp_asn1_enc_s32t_cnt(request->msg_security_model, &tlv.value_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->msg_security_model));
/* end of msgGlobalData */
request->outbound_msg_global_data_end = pbuf_stream->offset;
/* msgSecurityParameters */
request->outbound_msg_security_parameters_str_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 1, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
request->outbound_msg_security_parameters_seq_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 1, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
/* msgAuthoritativeEngineID */
request->msg_authoritative_engine_id_len = LWIP_SNMPV3_GET_ENGINE_ID_LEN();
memcpy(request->msg_authoritative_engine_id, LWIP_SNMPV3_GET_ENGINE_ID(), request->msg_authoritative_engine_id_len);
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->msg_authoritative_engine_id_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->msg_authoritative_engine_id, request->msg_authoritative_engine_id_len));
request->msg_authoritative_engine_time = snmpv3_get_engine_time();
request->msg_authoritative_engine_boots = snmpv3_get_engine_boots();
/* msgAuthoritativeEngineBoots */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(request->msg_authoritative_engine_boots, &tlv.value_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->msg_authoritative_engine_boots));
/* msgAuthoritativeEngineTime */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(request->msg_authoritative_engine_time, &tlv.value_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->msg_authoritative_engine_time));
/* msgUserName */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->msg_user_name_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->msg_user_name, request->msg_user_name_len));
#ifdef LWIP_SNMP_V3_CRYPTO
/* msgAuthenticationParameters */
if (request->msg_flags & SNMP_V3_AUTH_FLAG) {
memset(request->msg_authentication_parameters, 0, SNMP_V3_MAX_AUTH_PARAM_LENGTH);
request->outbound_msg_authentication_parameters_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 1, SNMP_V3_MAX_AUTH_PARAM_LENGTH);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->msg_authentication_parameters, SNMP_V3_MAX_AUTH_PARAM_LENGTH));
} else
#endif
{
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
}
#ifdef LWIP_SNMP_V3_CRYPTO
/* msgPrivacyParameters */
if (request->msg_flags & SNMP_V3_PRIV_FLAG) {
snmpv3_build_priv_param(request->msg_privacy_parameters);
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, SNMP_V3_MAX_PRIV_PARAM_LENGTH);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->msg_privacy_parameters, SNMP_V3_MAX_PRIV_PARAM_LENGTH));
} else
#endif
{
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
}
/* End of msgSecurityParameters, so we can calculate the length of this sequence later */
request->outbound_msg_security_parameters_end = pbuf_stream->offset;
#ifdef LWIP_SNMP_V3_CRYPTO
/* For encryption we have to encapsulate the payload in an octet string */
if (request->msg_flags & SNMP_V3_PRIV_FLAG) {
request->outbound_scoped_pdu_string_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 3, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
}
#endif
/* Scoped PDU
* Encryption context
*/
request->outbound_scoped_pdu_seq_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, 0);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
/* contextEngineID */
request->context_engine_id_len = LWIP_SNMPV3_GET_ENGINE_ID_LEN();
memcpy(request->context_engine_id, LWIP_SNMPV3_GET_ENGINE_ID(), request->context_engine_id_len);
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->context_engine_id_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->context_engine_id, request->context_engine_id_len));
/* contextName */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->context_name_len);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(pbuf_stream, request->context_name, request->context_name_len));
}
#endif
/* 'PDU' sequence */
request->outbound_pdu_offset = pbuf_stream->offset;
@ -937,6 +1293,7 @@ snmp_complete_outbound_frame(struct snmp_request *request)
{
struct snmp_asn1_tlv tlv;
u16_t frame_size;
u8_t outbound_padding = 0;
if (request->version == SNMP_VERSION_1) {
if (request->error_status != SNMP_ERR_NOERROR) {
@ -987,13 +1344,55 @@ snmp_complete_outbound_frame(struct snmp_request *request)
frame_size = request->outbound_pbuf_stream.offset;
/* complete mssing length in 'Message' sequence ; 'Message' tlv is located at the beginning (offset 0) */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
#if LWIP_SNMP_V3 && defined(LWIP_SNMP_V3_CRYPTO)
/* Calculate padding for encryption */
if (request->version == SNMP_VERSION_3 && (request->msg_flags & SNMP_V3_PRIV_FLAG)) {
u8_t i;
for (i = 0; i < 8; i++) {
if ((frame_size + i - request->outbound_scoped_pdu_seq_offset) % 8 == 0) {
outbound_padding = i;
break;
}
snmp_pbuf_stream_write(&request->outbound_pbuf_stream, 0);
}
}
#endif
/* complete missing length in 'Message' sequence ; 'Message' tlv is located at the beginning (offset 0) */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size + outbound_padding - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_pbuf_stream_init(&(request->outbound_pbuf_stream), request->outbound_pbuf, 0, request->outbound_pbuf->tot_len) );
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
/* complete mssing length in 'PDU' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, (SNMP_ASN1_CLASS_CONTEXT | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_CONTEXT_PDU_GET_RESP), 3, frame_size - request->outbound_pdu_offset - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
#if LWIP_SNMP_V3
if (request->version == SNMP_VERSION_3) {
/* complete missing length in 'globalData' sequence */
/* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 1, request->outbound_msg_global_data_end
- request->outbound_msg_global_data_offset - 1 - 1);
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_msg_global_data_offset));
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv));
/* complete missing length in 'msgSecurityParameters' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 1, request->outbound_msg_security_parameters_end
- request->outbound_msg_security_parameters_str_offset - 1 - 1);
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_msg_security_parameters_str_offset));
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv));
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 1, request->outbound_msg_security_parameters_end
- request->outbound_msg_security_parameters_seq_offset - 1 - 1);
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_msg_security_parameters_seq_offset));
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv));
/* complete missing length in scoped PDU sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size - request->outbound_scoped_pdu_seq_offset - 1 - 3);
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_scoped_pdu_seq_offset));
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv));
}
#endif
/* complete missing length in 'PDU' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, (SNMP_ASN1_CLASS_CONTEXT | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_CONTEXT_PDU_GET_RESP), 3,
frame_size - request->outbound_pdu_offset - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_pdu_offset) );
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
@ -1051,12 +1450,56 @@ snmp_complete_outbound_frame(struct snmp_request *request)
OF_BUILD_EXEC( snmp_asn1_enc_s32t(&(request->outbound_pbuf_stream), len, request->error_index) );
}
/* complete mssing length in 'VarBindList' sequence ; 'VarBindList' tlv is located directly before varbind offset */
/* complete missing length in 'VarBindList' sequence ; 'VarBindList' tlv is located directly before varbind offset */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size - request->outbound_varbind_offset);
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_varbind_offset - 1 - 3) ); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
pbuf_realloc(request->outbound_pbuf, frame_size);
/* Authenticate response */
#if LWIP_SNMP_V3 && defined(LWIP_SNMP_V3_CRYPTO)
/* Encrypt response */
if (request->version == SNMP_VERSION_3 && (request->msg_flags & SNMP_V3_PRIV_FLAG)) {
u8_t* key;
u8_t algo;
/* complete missing length in PDU sequence */
OF_BUILD_EXEC(snmp_pbuf_stream_init(&request->outbound_pbuf_stream, request->outbound_pbuf, 0, request->outbound_pbuf->tot_len));
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_scoped_pdu_string_offset));
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 3, frame_size + outbound_padding
- request->outbound_scoped_pdu_string_offset - 1 - 3);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv));
OF_BUILD_EXEC(LWIP_SNMPV3_GET_USER(request->msg_user_name, NULL, NULL, &algo, &key));
OF_BUILD_EXEC(snmpv3_crypt(&request->outbound_pbuf_stream, tlv.value_len, key,
request->msg_privacy_parameters, request->msg_authoritative_engine_boots,
request->msg_authoritative_engine_time, algo, SNMP_V3_PRIV_MODE_ENCRYPT));
}
if (request->version == SNMP_VERSION_3 && (request->msg_flags & SNMP_V3_AUTH_FLAG)) {
u8_t* key;
u8_t algo;
u8_t hmac[20];
OF_BUILD_EXEC(LWIP_SNMPV3_GET_USER(request->msg_user_name, &algo, &key, NULL, NULL));
OF_BUILD_EXEC(snmp_pbuf_stream_init(&(request->outbound_pbuf_stream),
request->outbound_pbuf, 0, request->outbound_pbuf->tot_len));
OF_BUILD_EXEC(snmpv3_auth(&request->outbound_pbuf_stream, frame_size + outbound_padding, key, algo, hmac));
memcpy(request->msg_authentication_parameters, hmac, SNMP_V3_MAX_AUTH_PARAM_LENGTH);
OF_BUILD_EXEC(snmp_pbuf_stream_init(&request->outbound_pbuf_stream,
request->outbound_pbuf, 0, request->outbound_pbuf->tot_len));
OF_BUILD_EXEC(snmp_pbuf_stream_seek_abs(&request->outbound_pbuf_stream,
request->outbound_msg_authentication_parameters_offset));
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 1, SNMP_V3_MAX_AUTH_PARAM_LENGTH);
OF_BUILD_EXEC(snmp_ans1_enc_tlv(&request->outbound_pbuf_stream, &tlv));
OF_BUILD_EXEC(snmp_asn1_enc_raw(&request->outbound_pbuf_stream,
request->msg_authentication_parameters, SNMP_V3_MAX_AUTH_PARAM_LENGTH));
}
#endif
pbuf_realloc(request->outbound_pbuf, frame_size + outbound_padding);
snmp_stats.outgetresponses++;
snmp_stats.outpkts++;

37
src/apps/snmp/snmp_msg.h
View File

@ -5,6 +5,7 @@
/*
* Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
* Copyright (c) 2016 Elias Oenal.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
@ -31,6 +32,7 @@
*
* Author: Christiaan Simons <christiaan.simons@axon.tv>
* Martin Hentschel <info@cl-soft.de>
* Elias Oenal <lwip@eliasoenal.com>
*/
#ifndef LWIP_HDR_APPS_SNMP_MSG_H
@ -46,6 +48,10 @@
#include "lwip/ip_addr.h"
#include "lwip/err.h"
#if LWIP_SNMP_V3
#include "snmpv3.h"
#endif
#ifdef __cplusplus
extern "C" {
@ -65,6 +71,7 @@ extern "C" {
/* version defines used in PDU */
#define SNMP_VERSION_1 0
#define SNMP_VERSION_2c 1
#define SNMP_VERSION_3 3
struct snmp_varbind
{
@ -121,10 +128,30 @@ struct snmp_request
/* max-repetitions (getBulkRequest (SNMPv2c)) */
s32_t max_repetitions;
#if LWIP_SNMP_V3
s32_t msg_id;
s32_t msg_max_size;
u8_t msg_flags;
s32_t msg_security_model;
u8_t msg_authoritative_engine_id[SNMP_V3_MAX_ENGINE_ID_LENGTH];
u8_t msg_authoritative_engine_id_len;
s32_t msg_authoritative_engine_boots;
s32_t msg_authoritative_engine_time;
u8_t msg_user_name[SNMP_V3_MAX_USER_LENGTH];
u8_t msg_user_name_len;
u8_t msg_authentication_parameters[SNMP_V3_MAX_AUTH_PARAM_LENGTH];
u8_t msg_privacy_parameters[SNMP_V3_MAX_PRIV_PARAM_LENGTH];
u8_t context_engine_id[SNMP_V3_MAX_ENGINE_ID_LENGTH];
u8_t context_engine_id_len;
u8_t context_name[SNMP_V3_MAX_ENGINE_ID_LENGTH];
u8_t context_name_len;
#endif
struct pbuf *inbound_pbuf;
struct snmp_varbind_enumerator inbound_varbind_enumerator;
u16_t inbound_varbind_offset;
u16_t inbound_varbind_len;
u16_t inbound_padding_len;
struct pbuf *outbound_pbuf;
struct snmp_pbuf_stream outbound_pbuf_stream;
@ -132,6 +159,16 @@ struct snmp_request
u16_t outbound_error_status_offset;
u16_t outbound_error_index_offset;
u16_t outbound_varbind_offset;
#if LWIP_SNMP_V3
u16_t outbound_msg_global_data_offset;
u16_t outbound_msg_global_data_end;
u16_t outbound_msg_security_parameters_str_offset;
u16_t outbound_msg_security_parameters_seq_offset;
u16_t outbound_msg_security_parameters_end;
u16_t outbound_msg_authentication_parameters_offset;
u16_t outbound_scoped_pdu_seq_offset;
u16_t outbound_scoped_pdu_string_offset;
#endif
u8_t value_buffer[SNMP_MAX_VALUE_SIZE];
};

9
src/include/lwip/apps/snmp_opts.h
View File

@ -46,6 +46,15 @@
#define LWIP_SNMP 0
#endif
/**
* LWIP_SNMP_V3==1: This enables EXPERIMENTAL SNMPv3 support. LWIP_SNMP must
* also be enabled.
* THIS IS UNDER DEVELOPMENT AND SHOULD NOT BE ENABLED IN PRODUCTS.
*/
#ifndef LWIP_SNMP_V3
#define LWIP_SNMP_V3 0
#endif
/**
* SNMP_USE_NETCONN: Use netconn API instead of raw API.
* Makes SNMP agent run in a worker thread, so blocking operations