Commit message: snmp plugin: Fix double free of request PDU

snmp_sess_synch_response() always frees request PDU, in both case of request
error and success. If error condition occurs inside of `while (status == 0)`
loop, double free of `req` happens.

Issue: #2291
Signed-off-by: Florian Forster <octo@collectd.org>
CVE: CVE-2017-16820
CWE: CWE-415
Vulnerability description: The csnmp_read_table function in snmp.c in the SNMP plugin in collectd before 5.6.3 is susceptible to a double free in a certain error case, which could lead to a crash (or potentially have other impact).

Project: collectd
File: snmp.c

static void call_snmp_init_once(void) {
  static int have_init = 0;

  if (have_init == 0)
    init_snmp(PACKAGE_NAME);
  have_init = 1;
} /* void call_snmp_init_once */

Project: collectd
File: snmp.c

static int csnmp_config(oconfig_item_t *ci) {
  call_snmp_init_once();

  for (int i = 0; i < ci->children_num; i++) {
    oconfig_item_t *child = ci->children + i;
    if (strcasecmp("Data", child->key) == 0)
      csnmp_config_add_data(child);
    else if (strcasecmp("Host", child->key) == 0)
      csnmp_config_add_host(child);
    else {
      WARNING("snmp plugin: Ignoring unknown config option `%s'.", child->key);
    }
  } /* for (ci->children) */

  return (0);
} /* int csnmp_config */

Project: collectd
File: snmp.c

static int csnmp_config_add_data(oconfig_item_t *ci) {
  data_definition_t *dd;
  int status = 0;

  dd = calloc(1, sizeof(*dd));
  if (dd == NULL)
    return (-1);

  status = cf_util_get_string(ci, &dd->name);
  if (status != 0) {
    free(dd);
    return (-1);
  }

  dd->scale = 1.0;
  dd->shift = 0.0;

  for (int i = 0; i < ci->children_num; i++) {
    oconfig_item_t *option = ci->children + i;

    if (strcasecmp("Type", option->key) == 0)
      status = cf_util_get_string(option, &dd->type);
    else if (strcasecmp("Table", option->key) == 0)
      status = cf_util_get_boolean(option, &dd->is_table);
    else if (strcasecmp("Instance", option->key) == 0)
      status = csnmp_config_add_data_instance(dd, option);
    else if (strcasecmp("InstancePrefix", option->key) == 0)
      status = csnmp_config_add_data_instance_prefix(dd, option);
    else if (strcasecmp("Values", option->key) == 0)
      status = csnmp_config_add_data_values(dd, option);
    else if (strcasecmp("Shift", option->key) == 0)
      status = cf_util_get_double(option, &dd->shift);
    else if (strcasecmp("Scale", option->key) == 0)
      status = cf_util_get_double(option, &dd->scale);
    else if (strcasecmp("Ignore", option->key) == 0)
      status = csnmp_config_add_data_blacklist(dd, option);
    else if (strcasecmp("InvertMatch", option->key) == 0)
      status = csnmp_config_add_data_blacklist_match_inverted(dd, option);
    else {
      WARNING("snmp plugin: Option `%s' not allowed here.", option->key);
      status = -1;
    }

    if (status != 0)
      break;
  } /* for (ci->children) */

  while (status == 0) {
    if (dd->type == NULL) {
      WARNING("snmp plugin: `Type' not given for data `%s'", dd->name);
      status = -1;
      break;
    }
    if (dd->values == NULL) {
      WARNING("snmp plugin: No `Value' given for data `%s'", dd->name);
      status = -1;
      break;
    }

    break;
  } /* while (status == 0) */

  if (status != 0) {
    sfree(dd->name);
    sfree(dd->instance_prefix);
    sfree(dd->values);
    sfree(dd->ignores);
    sfree(dd);
    return (-1);
  }

  DEBUG("snmp plugin: dd = { name = %s, type = %s, is_table = %s, values_len = "
        "%zu }",
        dd->name, dd->type, (dd->is_table != 0) ? "true" : "false",
        dd->values_len);

  if (data_head == NULL)
    data_head = dd;
  else {
    data_definition_t *last;
    last = data_head;
    while (last->next != NULL)
      last = last->next;
    last->next = dd;
  }

  return (0);
} /* int csnmp_config_add_data */

Project: collectd
File: snmp.c

static int csnmp_config_add_data_blacklist(data_definition_t *dd,
                                           oconfig_item_t *ci) {
  if (ci->values_num < 1)
    return (0);

  for (int i = 0; i < ci->values_num; i++) {
    if (ci->values[i].type != OCONFIG_TYPE_STRING) {
      WARNING("snmp plugin: `Ignore' needs only string argument.");
      return (-1);
    }
  }

  dd->ignores_len = 0;
  dd->ignores = NULL;

  for (int i = 0; i < ci->values_num; ++i) {
    if (strarray_add(&(dd->ignores), &(dd->ignores_len),
                     ci->values[i].value.string) != 0) {
      ERROR("snmp plugin: Can't allocate memory");
      strarray_free(dd->ignores, dd->ignores_len);
      return (ENOMEM);
    }
  }
  return 0;
} /* int csnmp_config_add_data_blacklist */

Project: collectd
File: snmp.c

static int csnmp_config_add_data_blacklist_match_inverted(data_definition_t *dd,
                                                          oconfig_item_t *ci) {
  if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_BOOLEAN)) {
    WARNING("snmp plugin: `InvertMatch' needs exactly one boolean argument.");
    return (-1);
  }

  dd->invert_match = ci->values[0].value.boolean ? 1 : 0;

  return (0);
} /* int csnmp_config_add_data_blacklist_match_inverted */

Project: collectd
File: snmp.c

static int csnmp_config_add_data_instance(data_definition_t *dd,
                                          oconfig_item_t *ci) {
  char buffer[DATA_MAX_NAME_LEN];
  int status;

  status = cf_util_get_string_buffer(ci, buffer, sizeof(buffer));
  if (status != 0)
    return status;

  if (dd->is_table) {
    /* Instance is an OID */
    dd->instance.oid.oid_len = MAX_OID_LEN;

    if (!read_objid(buffer, dd->instance.oid.oid, &dd->instance.oid.oid_len)) {
      ERROR("snmp plugin: read_objid (%s) failed.", buffer);
      return (-1);
    }
  } else {
    /* Instance is a simple string */
    sstrncpy(dd->instance.string, buffer, sizeof(dd->instance.string));
  }

  return (0);
} /* int csnmp_config_add_data_instance */

Project: collectd
File: snmp.c

static int csnmp_config_add_data_values(data_definition_t *dd,
                                        oconfig_item_t *ci) {
  if (ci->values_num < 1) {
    WARNING("snmp plugin: `Values' needs at least one argument.");
    return (-1);
  }

  for (int i = 0; i < ci->values_num; i++)
    if (ci->values[i].type != OCONFIG_TYPE_STRING) {
      WARNING("snmp plugin: `Values' needs only string argument.");
      return (-1);
    }

  sfree(dd->values);
  dd->values_len = 0;
  dd->values = malloc(sizeof(*dd->values) * ci->values_num);
  if (dd->values == NULL)
    return (-1);
  dd->values_len = (size_t)ci->values_num;

  for (int i = 0; i < ci->values_num; i++) {
    dd->values[i].oid_len = MAX_OID_LEN;

    if (NULL == snmp_parse_oid(ci->values[i].value.string, dd->values[i].oid,
                               &dd->values[i].oid_len)) {
      ERROR("snmp plugin: snmp_parse_oid (%s) failed.",
            ci->values[i].value.string);
      free(dd->values);
      dd->values = NULL;
      dd->values_len = 0;
      return (-1);
    }
  }

  return (0);
} /* int csnmp_config_add_data_instance */

Project: collectd
File: snmp.c

static int csnmp_config_add_host_auth_protocol(host_definition_t *hd,
                                               oconfig_item_t *ci) {
  char buffer[4];
  int status;

  status = cf_util_get_string_buffer(ci, buffer, sizeof(buffer));
  if (status != 0)
    return status;

  if (strcasecmp("MD5", buffer) == 0) {
    hd->auth_protocol = usmHMACMD5AuthProtocol;
    hd->auth_protocol_len = sizeof(usmHMACMD5AuthProtocol) / sizeof(oid);
  } else if (strcasecmp("SHA", buffer) == 0) {
    hd->auth_protocol = usmHMACSHA1AuthProtocol;
    hd->auth_protocol_len = sizeof(usmHMACSHA1AuthProtocol) / sizeof(oid);
  } else {
    WARNING("snmp plugin: The `AuthProtocol' config option must be `MD5' or "
            "`SHA'.");
    return (-1);
  }

  DEBUG("snmp plugin: host = %s; host->auth_protocol = %s;", hd->name,
        hd->auth_protocol == usmHMACMD5AuthProtocol ? "MD5" : "SHA");

  return (0);
} /* int csnmp_config_add_host_auth_protocol */

Project: collectd
File: snmp.c

static int csnmp_config_add_host_collect(host_definition_t *host,
                                         oconfig_item_t *ci) {
  data_definition_t *data;
  data_definition_t **data_list;
  int data_list_len;

  if (ci->values_num < 1) {
    WARNING("snmp plugin: `Collect' needs at least one argument.");
    return (-1);
  }

  for (int i = 0; i < ci->values_num; i++)
    if (ci->values[i].type != OCONFIG_TYPE_STRING) {
      WARNING("snmp plugin: All arguments to `Collect' must be strings.");
      return (-1);
    }

  data_list_len = host->data_list_len + ci->values_num;
  data_list =
      realloc(host->data_list, sizeof(data_definition_t *) * data_list_len);
  if (data_list == NULL)
    return (-1);
  host->data_list = data_list;

  for (int i = 0; i < ci->values_num; i++) {
    for (data = data_head; data != NULL; data = data->next)
      if (strcasecmp(ci->values[i].value.string, data->name) == 0)
        break;

    if (data == NULL) {
      WARNING("snmp plugin: No such data configured: `%s'",
              ci->values[i].value.string);
      continue;
    }

    DEBUG("snmp plugin: Collect: host = %s, data[%i] = %s;", host->name,
          host->data_list_len, data->name);

    host->data_list[host->data_list_len] = data;
    host->data_list_len++;
  } /* for (values_num) */

  return (0);
} /* int csnmp_config_add_host_collect */

Project: collectd
File: snmp.c

static int csnmp_config_add_host_priv_protocol(host_definition_t *hd,
                                               oconfig_item_t *ci) {
  char buffer[4];
  int status;

  status = cf_util_get_string_buffer(ci, buffer, sizeof(buffer));
  if (status != 0)
    return status;

  if (strcasecmp("AES", buffer) == 0) {
    hd->priv_protocol = usmAESPrivProtocol;
    hd->priv_protocol_len = sizeof(usmAESPrivProtocol) / sizeof(oid);
  } else if (strcasecmp("DES", buffer) == 0) {
    hd->priv_protocol = usmDESPrivProtocol;
    hd->priv_protocol_len = sizeof(usmDESPrivProtocol) / sizeof(oid);
  } else {
    WARNING("snmp plugin: The `PrivProtocol' config option must be `AES' or "
            "`DES'.");
    return (-1);
  }

  DEBUG("snmp plugin: host = %s; host->priv_protocol = %s;", hd->name,
        hd->priv_protocol == usmAESPrivProtocol ? "AES" : "DES");

  return (0);
} /* int csnmp_config_add_host_priv_protocol */

Project: collectd
File: snmp.c

static int csnmp_config_add_host_security_level(host_definition_t *hd,
                                                oconfig_item_t *ci) {
  char buffer[16];
  int status;

  status = cf_util_get_string_buffer(ci, buffer, sizeof(buffer));
  if (status != 0)
    return status;

  if (strcasecmp("noAuthNoPriv", buffer) == 0)
    hd->security_level = SNMP_SEC_LEVEL_NOAUTH;
  else if (strcasecmp("authNoPriv", buffer) == 0)
    hd->security_level = SNMP_SEC_LEVEL_AUTHNOPRIV;
  else if (strcasecmp("authPriv", buffer) == 0)
    hd->security_level = SNMP_SEC_LEVEL_AUTHPRIV;
  else {
    WARNING("snmp plugin: The `SecurityLevel' config option must be "
            "`noAuthNoPriv', `authNoPriv', or `authPriv'.");
    return (-1);
  }

  DEBUG("snmp plugin: host = %s; host->security_level = %d;", hd->name,
        hd->security_level);

  return (0);
} /* int csnmp_config_add_host_security_level */

Project: collectd
File: snmp.c

static int csnmp_dispatch_table(host_definition_t *host,
                                data_definition_t *data,
                                csnmp_list_instances_t *instance_list,
                                csnmp_table_values_t **value_table) {
  const data_set_t *ds;
  value_list_t vl = VALUE_LIST_INIT;

  csnmp_list_instances_t *instance_list_ptr;
  csnmp_table_values_t **value_table_ptr;

  size_t i;
  _Bool have_more;
  oid_t current_suffix;

  ds = plugin_get_ds(data->type);
  if (!ds) {
    ERROR("snmp plugin: DataSet `%s' not defined.", data->type);
    return (-1);
  }
  assert(ds->ds_num == data->values_len);
  assert(data->values_len > 0);

  instance_list_ptr = instance_list;

  value_table_ptr = calloc(data->values_len, sizeof(*value_table_ptr));
  if (value_table_ptr == NULL)
    return (-1);
  for (i = 0; i < data->values_len; i++)
    value_table_ptr[i] = value_table[i];

  vl.values_len = data->values_len;
  vl.values = malloc(sizeof(*vl.values) * vl.values_len);
  if (vl.values == NULL) {
    ERROR("snmp plugin: malloc failed.");
    sfree(value_table_ptr);
    return (-1);
  }

  sstrncpy(vl.host, host->name, sizeof(vl.host));
  sstrncpy(vl.plugin, "snmp", sizeof(vl.plugin));

  vl.interval = host->interval;

  have_more = 1;
  while (have_more) {
    _Bool suffix_skipped = 0;

    /* Determine next suffix to handle. */
    if (instance_list != NULL) {
      if (instance_list_ptr == NULL) {
        have_more = 0;
        continue;
      }

      memcpy(&current_suffix, &instance_list_ptr->suffix,
             sizeof(current_suffix));
    } else /* no instance configured */
    {
      csnmp_table_values_t *ptr = value_table_ptr[0];
      if (ptr == NULL) {
        have_more = 0;
        continue;
      }

      memcpy(&current_suffix, &ptr->suffix, sizeof(current_suffix));
    }

    /* Update all the value_table_ptr to point at the entry with the same
     * trailing partial OID */
    for (i = 0; i < data->values_len; i++) {
      while (
          (value_table_ptr[i] != NULL) &&
          (csnmp_oid_compare(&value_table_ptr[i]->suffix, &current_suffix) < 0))
        value_table_ptr[i] = value_table_ptr[i]->next;

      if (value_table_ptr[i] == NULL) {
        have_more = 0;
        break;
      } else if (csnmp_oid_compare(&value_table_ptr[i]->suffix,
                                   &current_suffix) > 0) {
        /* This suffix is missing in the subtree. Indicate this with the
         * "suffix_skipped" flag and try the next instance / suffix. */
        suffix_skipped = 1;
        break;
      }
    } /* for (i = 0; i < columns; i++) */

    if (!have_more)
      break;

    /* Matching the values failed. Start from the beginning again. */
    if (suffix_skipped) {
      if (instance_list != NULL)
        instance_list_ptr = instance_list_ptr->next;
      else
        value_table_ptr[0] = value_table_ptr[0]->next;

      continue;
    }

/* if we reach this line, all value_table_ptr[i] are non-NULL and are set
 * to the same subid. instance_list_ptr is either NULL or points to the
 * same subid, too. */
#if COLLECT_DEBUG
    for (i = 1; i < data->values_len; i++) {
      assert(value_table_ptr[i] != NULL);
      assert(csnmp_oid_compare(&value_table_ptr[i - 1]->suffix,
                               &value_table_ptr[i]->suffix) == 0);
    }
    assert((instance_list_ptr == NULL) ||
           (csnmp_oid_compare(&instance_list_ptr->suffix,
                              &value_table_ptr[0]->suffix) == 0));
#endif

    sstrncpy(vl.type, data->type, sizeof(vl.type));

    {
      char temp[DATA_MAX_NAME_LEN];

      if (instance_list_ptr == NULL)
        csnmp_oid_to_string(temp, sizeof(temp), &current_suffix);
      else
        sstrncpy(temp, instance_list_ptr->instance, sizeof(temp));

      if (data->instance_prefix == NULL)
        sstrncpy(vl.type_instance, temp, sizeof(vl.type_instance));
      else
        ssnprintf(vl.type_instance, sizeof(vl.type_instance), "%s%s",
                  data->instance_prefix, temp);
    }

    for (i = 0; i < data->values_len; i++)
      vl.values[i] = value_table_ptr[i]->value;

    /* If we get here `vl.type_instance' and all `vl.values' have been set
     * vl.type_instance can be empty, i.e. a blank port description on a
     * switch if you're using IF-MIB::ifDescr as Instance.
     */
    if (vl.type_instance[0] != '\0')
      plugin_dispatch_values(&vl);

    if (instance_list != NULL)
      instance_list_ptr = instance_list_ptr->next;
    else
      value_table_ptr[0] = value_table_ptr[0]->next;
  } /* while (have_more) */

  sfree(vl.values);
  sfree(value_table_ptr);

  return (0);
} /* int csnmp_dispatch_table */

Project: collectd
File: snmp.c

static void csnmp_host_close_session(host_definition_t *host) /* {{{ */
{
  if (host->sess_handle == NULL)
    return;

  snmp_sess_close(host->sess_handle);
  host->sess_handle = NULL;
} /* }}} void csnmp_host_close_session */

Project: collectd
File: snmp.c

static void csnmp_host_open_session(host_definition_t *host) {
  struct snmp_session sess;
  int error;

  if (host->sess_handle != NULL)
    csnmp_host_close_session(host);

  snmp_sess_init(&sess);
  sess.peername = host->address;
  switch (host->version) {
  case 1:
    sess.version = SNMP_VERSION_1;
    break;
  case 3:
    sess.version = SNMP_VERSION_3;
    break;
  default:
    sess.version = SNMP_VERSION_2c;
    break;
  }

  if (host->version == 3) {
    sess.securityName = host->username;
    sess.securityNameLen = strlen(host->username);
    sess.securityLevel = host->security_level;

    if (sess.securityLevel == SNMP_SEC_LEVEL_AUTHNOPRIV ||
        sess.securityLevel == SNMP_SEC_LEVEL_AUTHPRIV) {
      sess.securityAuthProto = host->auth_protocol;
      sess.securityAuthProtoLen = host->auth_protocol_len;
      sess.securityAuthKeyLen = USM_AUTH_KU_LEN;
      error = generate_Ku(sess.securityAuthProto, sess.securityAuthProtoLen,
                          (u_char *)host->auth_passphrase,
                          strlen(host->auth_passphrase), sess.securityAuthKey,
                          &sess.securityAuthKeyLen);
      if (error != SNMPERR_SUCCESS) {
        ERROR("snmp plugin: host %s: Error generating Ku from auth_passphrase. "
              "(Error %d)",
              host->name, error);
      }
    }

    if (sess.securityLevel == SNMP_SEC_LEVEL_AUTHPRIV) {
      sess.securityPrivProto = host->priv_protocol;
      sess.securityPrivProtoLen = host->priv_protocol_len;
      sess.securityPrivKeyLen = USM_PRIV_KU_LEN;
      error = generate_Ku(sess.securityAuthProto, sess.securityAuthProtoLen,
                          (u_char *)host->priv_passphrase,
                          strlen(host->priv_passphrase), sess.securityPrivKey,
                          &sess.securityPrivKeyLen);
      if (error != SNMPERR_SUCCESS) {
        ERROR("snmp plugin: host %s: Error generating Ku from priv_passphrase. "
              "(Error %d)",
              host->name, error);
      }
    }

    if (host->context != NULL) {
      sess.contextName = host->context;
      sess.contextNameLen = strlen(host->context);
    }
  } else /* SNMPv1/2 "authenticates" with community string */
  {
    sess.community = (u_char *)host->community;
    sess.community_len = strlen(host->community);
  }

  /* snmp_sess_open will copy the `struct snmp_session *'. */
  host->sess_handle = snmp_sess_open(&sess);

  if (host->sess_handle == NULL) {
    char *errstr = NULL;

    snmp_error(&sess, NULL, NULL, &errstr);

    ERROR("snmp plugin: host %s: snmp_sess_open failed: %s", host->name,
          (errstr == NULL) ? "Unknown problem" : errstr);
    sfree(errstr);
  }
} /* void csnmp_host_open_session */

Project: collectd
File: snmp.c

static int csnmp_init(void) {
  call_snmp_init_once();

  return (0);
} /* int csnmp_init */

Project: collectd
File: snmp.c

static int csnmp_instance_list_add(csnmp_list_instances_t **head,
                                   csnmp_list_instances_t **tail,
                                   const struct snmp_pdu *res,
                                   const host_definition_t *hd,
                                   const data_definition_t *dd) {
  csnmp_list_instances_t *il;
  struct variable_list *vb;
  oid_t vb_name;
  int status;
  uint32_t is_matched;

  /* Set vb on the last variable */
  for (vb = res->variables; (vb != NULL) && (vb->next_variable != NULL);
       vb = vb->next_variable)
    /* do nothing */;
  if (vb == NULL)
    return (-1);

  csnmp_oid_init(&vb_name, vb->name, vb->name_length);

  il = calloc(1, sizeof(*il));
  if (il == NULL) {
    ERROR("snmp plugin: calloc failed.");
    return (-1);
  }
  il->next = NULL;

  status = csnmp_oid_suffix(&il->suffix, &vb_name, &dd->instance.oid);
  if (status != 0) {
    sfree(il);
    return (status);
  }

  /* Get instance name */
  if ((vb->type == ASN_OCTET_STR) || (vb->type == ASN_BIT_STR) ||
      (vb->type == ASN_IPADDRESS)) {
    char *ptr;

    csnmp_strvbcopy(il->instance, vb, sizeof(il->instance));
    is_matched = 0;
    for (uint32_t i = 0; i < dd->ignores_len; i++) {
      status = fnmatch(dd->ignores[i], il->instance, 0);
      if (status == 0) {
        if (dd->invert_match == 0) {
          sfree(il);
          return 0;
        } else {
          is_matched = 1;
          break;
        }
      }
    }
    if (dd->invert_match != 0 && is_matched == 0) {
      sfree(il);
      return 0;
    }
    for (ptr = il->instance; *ptr != '\0'; ptr++) {
      if ((*ptr > 0) && (*ptr < 32))
        *ptr = ' ';
      else if (*ptr == '/')
        *ptr = '_';
    }
    DEBUG("snmp plugin: il->instance = `%s';", il->instance);
  } else {
    value_t val = csnmp_value_list_to_value(
        vb, DS_TYPE_COUNTER,
        /* scale = */ 1.0, /* shift = */ 0.0, hd->name, dd->name);
    ssnprintf(il->instance, sizeof(il->instance), "%llu", val.counter);
  }

  /* TODO: Debugging output */

  if (*head == NULL)
    *head = il;
  else
    (*tail)->next = il;
  *tail = il;

  return (0);
} /* int csnmp_instance_list_add */

Project: collectd
File: snmp.c

static int csnmp_oid_compare(oid_t const *left, oid_t const *right) {
  return (
      snmp_oid_compare(left->oid, left->oid_len, right->oid, right->oid_len));
}

Project: collectd
File: snmp.c

static void csnmp_oid_init(oid_t *dst, oid const *src, size_t n) {
  assert(n <= STATIC_ARRAY_SIZE(dst->oid));
  memcpy(dst->oid, src, sizeof(*src) * n);
  dst->oid_len = n;
}

Project: collectd
File: snmp.c

static int csnmp_oid_suffix(oid_t *dst, oid_t const *src, oid_t const *root) {
  /* Make sure "src" is in "root"s subtree. */
  if (src->oid_len <= root->oid_len)
    return (EINVAL);
  if (snmp_oid_ncompare(root->oid, root->oid_len, src->oid, src->oid_len,
                        /* n = */ root->oid_len) != 0)
    return (EINVAL);

  memset(dst, 0, sizeof(*dst));
  dst->oid_len = src->oid_len - root->oid_len;
  memcpy(dst->oid, &src->oid[root->oid_len],
         dst->oid_len * sizeof(dst->oid[0]));
  return (0);
}

Project: collectd
File: snmp.c

static int csnmp_oid_to_string(char *buffer, size_t buffer_size,
                               oid_t const *o) {
  char oid_str[MAX_OID_LEN][16];
  char *oid_str_ptr[MAX_OID_LEN];

  for (size_t i = 0; i < o->oid_len; i++) {
    ssnprintf(oid_str[i], sizeof(oid_str[i]), "%lu", (unsigned long)o->oid[i]);
    oid_str_ptr[i] = oid_str[i];
  }

  return (strjoin(buffer, buffer_size, oid_str_ptr, o->oid_len,
                  /* separator = */ "."));
}

Project: collectd
File: snmp.c

static int csnmp_read_host(user_data_t *ud) {
  host_definition_t *host;
  int status;
  int success;
  int i;

  host = ud->data;

  if (host->interval == 0)
    host->interval = plugin_get_interval();

  if (host->sess_handle == NULL)
    csnmp_host_open_session(host);

  if (host->sess_handle == NULL)
    return (-1);

  success = 0;
  for (i = 0; i < host->data_list_len; i++) {
    data_definition_t *data = host->data_list[i];

    if (data->is_table)
      status = csnmp_read_table(host, data);
    else
      status = csnmp_read_value(host, data);

    if (status == 0)
      success++;
  }

  if (success == 0)
    return (-1);

  return (0);
} /* int csnmp_read_host */

Project: collectd
File: snmp.c

static int csnmp_read_value(host_definition_t *host, data_definition_t *data) {
  struct snmp_pdu *req;
  struct snmp_pdu *res = NULL;
  struct variable_list *vb;

  const data_set_t *ds;
  value_list_t vl = VALUE_LIST_INIT;

  int status;
  size_t i;

  DEBUG("snmp plugin: csnmp_read_value (host = %s, data = %s)", host->name,
        data->name);

  if (host->sess_handle == NULL) {
    DEBUG("snmp plugin: csnmp_read_value: host->sess_handle == NULL");
    return (-1);
  }

  ds = plugin_get_ds(data->type);
  if (!ds) {
    ERROR("snmp plugin: DataSet `%s' not defined.", data->type);
    return (-1);
  }

  if (ds->ds_num != data->values_len) {
    ERROR("snmp plugin: DataSet `%s' requires %zu values, but config talks "
          "about %zu",
          data->type, ds->ds_num, data->values_len);
    return (-1);
  }

  vl.values_len = ds->ds_num;
  vl.values = malloc(sizeof(*vl.values) * vl.values_len);
  if (vl.values == NULL)
    return (-1);
  for (i = 0; i < vl.values_len; i++) {
    if (ds->ds[i].type == DS_TYPE_COUNTER)
      vl.values[i].counter = 0;
    else
      vl.values[i].gauge = NAN;
  }

  sstrncpy(vl.host, host->name, sizeof(vl.host));
  sstrncpy(vl.plugin, "snmp", sizeof(vl.plugin));
  sstrncpy(vl.type, data->type, sizeof(vl.type));
  sstrncpy(vl.type_instance, data->instance.string, sizeof(vl.type_instance));

  vl.interval = host->interval;

  req = snmp_pdu_create(SNMP_MSG_GET);
  if (req == NULL) {
    ERROR("snmp plugin: snmp_pdu_create failed.");
    sfree(vl.values);
    return (-1);
  }

  for (i = 0; i < data->values_len; i++)
    snmp_add_null_var(req, data->values[i].oid, data->values[i].oid_len);

  status = snmp_sess_synch_response(host->sess_handle, req, &res);

  if ((status != STAT_SUCCESS) || (res == NULL)) {
    char *errstr = NULL;

    snmp_sess_error(host->sess_handle, NULL, NULL, &errstr);
    ERROR("snmp plugin: host %s: snmp_sess_synch_response failed: %s",
          host->name, (errstr == NULL) ? "Unknown problem" : errstr);

    if (res != NULL)
      snmp_free_pdu(res);

    sfree(errstr);
    sfree(vl.values);
    csnmp_host_close_session(host);

    return (-1);
  }

  for (vb = res->variables; vb != NULL; vb = vb->next_variable) {
#if COLLECT_DEBUG
    char buffer[1024];
    snprint_variable(buffer, sizeof(buffer), vb->name, vb->name_length, vb);
    DEBUG("snmp plugin: Got this variable: %s", buffer);
#endif /* COLLECT_DEBUG */

    for (i = 0; i < data->values_len; i++)
      if (snmp_oid_compare(data->values[i].oid, data->values[i].oid_len,
                           vb->name, vb->name_length) == 0)
        vl.values[i] =
            csnmp_value_list_to_value(vb, ds->ds[i].type, data->scale,
                                      data->shift, host->name, data->name);
  } /* for (res->variables) */

  snmp_free_pdu(res);

  DEBUG("snmp plugin: -> plugin_dispatch_values (&vl);");
  plugin_dispatch_values(&vl);
  sfree(vl.values);

  return (0);
} /* int csnmp_read_value */

Project: collectd
File: snmp.c

static int csnmp_shutdown(void) {
  data_definition_t *data_this;
  data_definition_t *data_next;

  /* When we get here, the read threads have been stopped and all the
   * `host_definition_t' will be freed. */
  DEBUG("snmp plugin: Destroying all data definitions.");

  data_this = data_head;
  data_head = NULL;
  while (data_this != NULL) {
    data_next = data_this->next;

    sfree(data_this->name);
    sfree(data_this->type);
    sfree(data_this->values);
    sfree(data_this->ignores);
    sfree(data_this);

    data_this = data_next;
  }

  return (0);
} /* int csnmp_shutdown */

Project: collectd
File: snmp.c

static int csnmp_strvbcopy(char *dst, /* {{{ */
                           const struct variable_list *vb, size_t dst_size) {
  char *src;
  size_t num_chars;

  if (vb->type == ASN_OCTET_STR)
    src = (char *)vb->val.string;
  else if (vb->type == ASN_BIT_STR)
    src = (char *)vb->val.bitstring;
  else if (vb->type == ASN_IPADDRESS) {
    return ssnprintf(dst, dst_size,
                     "%" PRIu8 ".%" PRIu8 ".%" PRIu8 ".%" PRIu8 "",
                     (uint8_t)vb->val.string[0], (uint8_t)vb->val.string[1],
                     (uint8_t)vb->val.string[2], (uint8_t)vb->val.string[3]);
  } else {
    dst[0] = 0;
    return (EINVAL);
  }

  num_chars = dst_size - 1;
  if (num_chars > vb->val_len)
    num_chars = vb->val_len;

  for (size_t i = 0; i < num_chars; i++) {
    /* Check for control characters. */
    if ((unsigned char)src[i] < 32)
      return (csnmp_strvbcopy_hexstring(dst, vb, dst_size));
    dst[i] = src[i];
  }
  dst[num_chars] = 0;
  dst[dst_size - 1] = 0;

  if (dst_size <= vb->val_len)
    return ENOMEM;

  return 0;
} /* }}} int csnmp_strvbcopy */

Project: collectd
File: snmp.c

static value_t csnmp_value_list_to_value(struct variable_list *vl, int type,
                                         double scale, double shift,
                                         const char *host_name,
                                         const char *data_name) {
  value_t ret;
  uint64_t tmp_unsigned = 0;
  int64_t tmp_signed = 0;
  _Bool defined = 1;
  /* Set to true when the original SNMP type appears to have been signed. */
  _Bool prefer_signed = 0;

  if ((vl->type == ASN_INTEGER) || (vl->type == ASN_UINTEGER) ||
      (vl->type == ASN_COUNTER)
#ifdef ASN_TIMETICKS
      || (vl->type == ASN_TIMETICKS)
#endif
      || (vl->type == ASN_GAUGE)) {
    tmp_unsigned = (uint32_t)*vl->val.integer;
    tmp_signed = (int32_t)*vl->val.integer;

    if (vl->type == ASN_INTEGER)
      prefer_signed = 1;

    DEBUG("snmp plugin: Parsed int32 value is %" PRIu64 ".", tmp_unsigned);
  } else if (vl->type == ASN_COUNTER64) {
    tmp_unsigned = (uint32_t)vl->val.counter64->high;
    tmp_unsigned = tmp_unsigned << 32;
    tmp_unsigned += (uint32_t)vl->val.counter64->low;
    tmp_signed = (int64_t)tmp_unsigned;
    DEBUG("snmp plugin: Parsed int64 value is %" PRIu64 ".", tmp_unsigned);
  } else if (vl->type == ASN_OCTET_STR) {
    /* We'll handle this later.. */
  } else {
    char oid_buffer[1024] = {0};

    snprint_objid(oid_buffer, sizeof(oid_buffer) - 1, vl->name,
                  vl->name_length);

#ifdef ASN_NULL
    if (vl->type == ASN_NULL)
      INFO("snmp plugin: OID \"%s\" is undefined (type ASN_NULL)", oid_buffer);
    else
#endif
      WARNING("snmp plugin: I don't know the ASN type #%i "
              "(OID: \"%s\", data block \"%s\", host block \"%s\")",
              (int)vl->type, oid_buffer,
              (data_name != NULL) ? data_name : "UNKNOWN",
              (host_name != NULL) ? host_name : "UNKNOWN");

    defined = 0;
  }

  if (vl->type == ASN_OCTET_STR) {
    int status = -1;

    if (vl->val.string != NULL) {
      char string[64];
      size_t string_length;

      string_length = sizeof(string) - 1;
      if (vl->val_len < string_length)
        string_length = vl->val_len;

      /* The strings we get from the Net-SNMP library may not be null
       * terminated. That is why we're using `memcpy' here and not `strcpy'.
       * `string_length' is set to `vl->val_len' which holds the length of the
       * string.  -octo */
      memcpy(string, vl->val.string, string_length);
      string[string_length] = 0;

      status = parse_value(string, &ret, type);
      if (status != 0) {
        ERROR("snmp plugin: host %s: csnmp_value_list_to_value: Parsing string "
              "as %s failed: %s",
              (host_name != NULL) ? host_name : "UNKNOWN",
              DS_TYPE_TO_STRING(type), string);
      }
    }

    if (status != 0) {
      switch (type) {
      case DS_TYPE_COUNTER:
      case DS_TYPE_DERIVE:
      case DS_TYPE_ABSOLUTE:
        memset(&ret, 0, sizeof(ret));
        break;

      case DS_TYPE_GAUGE:
        ret.gauge = NAN;
        break;

      default:
        ERROR("snmp plugin: csnmp_value_list_to_value: Unknown "
              "data source type: %i.",
              type);
        ret.gauge = NAN;
      }
    }
  } /* if (vl->type == ASN_OCTET_STR) */
  else if (type == DS_TYPE_COUNTER) {
    ret.counter = tmp_unsigned;
  } else if (type == DS_TYPE_GAUGE) {
    if (!defined)
      ret.gauge = NAN;
    else if (prefer_signed)
      ret.gauge = (scale * tmp_signed) + shift;
    else
      ret.gauge = (scale * tmp_unsigned) + shift;
  } else if (type == DS_TYPE_DERIVE) {
    if (prefer_signed)
      ret.derive = (derive_t)tmp_signed;
    else
      ret.derive = (derive_t)tmp_unsigned;
  } else if (type == DS_TYPE_ABSOLUTE) {
    ret.absolute = (absolute_t)tmp_unsigned;
  } else {
    ERROR("snmp plugin: csnmp_value_list_to_value: Unknown data source "
          "type: %i.",
          type);
    ret.gauge = NAN;
  }

  return (ret);
} /* value_t csnmp_value_list_to_value */

Project: collectd
File: snmp.c

void module_register(void) {
  plugin_register_complex_config("snmp", csnmp_config);
  plugin_register_init("snmp", csnmp_init);
  plugin_register_shutdown("snmp", csnmp_shutdown);
} /* void module_register */