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Feature/safe decode npdu (#84)

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* Added safe version to decode npdu

* Calling safe decoder function.

* Added comments and apdu_len checks.

* Fixed signed/unsigned warnings.
This commit is contained in:
Roy Schneider
2020-05-11 15:30:18 +02:00
committed by GitHub
parent ec923e51a3
commit 094ac1db00
5 changed files with 170 additions and 77 deletions
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src/bacnet/whohas.c
+57 -33
View File
@@ -39,8 +39,12 @@
/** @file whohas.c Encode/Decode Who-Has requests */
/* encode service - use -1 for limit for unlimited */
/** Encode Who-Hasservice - use -1 for limit for unlimited
*
* @param apdu Pointer to the APDU.
* @param data Pointer to the Who-Has application data.
*
* @return Bytes encoded. */
int whohas_encode_apdu(uint8_t *apdu, BACNET_WHO_HAS_DATA *data)
{
int len = 0; /* length of each encoding */
@@ -75,7 +79,13 @@ int whohas_encode_apdu(uint8_t *apdu, BACNET_WHO_HAS_DATA *data)
return apdu_len;
}
/* decode the service request only */
/** Decode the Who-Has service request only.
*
* @param apdu Pointer to the received data.
* @param apdu_len Bytes valid in the receive buffer.
* @param data Pointer to the application dta to be filled in.
*
* @return Bytes decoded. */
int whohas_decode_service_request(
uint8_t *apdu, unsigned apdu_len, BACNET_WHO_HAS_DATA *data)
{
@@ -90,42 +100,56 @@ int whohas_decode_service_request(
if (decode_is_context_tag(&apdu[len], 0)) {
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
len += decode_unsigned(&apdu[len], len_value, &unsigned_value);
if (unsigned_value <= BACNET_MAX_INSTANCE) {
data->low_limit = unsigned_value;
}
if (!decode_is_context_tag(&apdu[len], 1)) {
return -1;
}
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
len += decode_unsigned(&apdu[len], len_value, &unsigned_value);
if (unsigned_value <= BACNET_MAX_INSTANCE) {
data->high_limit = unsigned_value;
if ((unsigned)len < apdu_len) {
len += decode_unsigned(&apdu[len], len_value, &unsigned_value);
if ((unsigned)len < apdu_len) {
if (unsigned_value <= BACNET_MAX_INSTANCE) {
data->low_limit = unsigned_value;
}
if (!decode_is_context_tag(&apdu[len], 1)) {
return -1;
}
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
if ((unsigned)len < apdu_len) {
len += decode_unsigned(&apdu[len], len_value, &unsigned_value);
if (unsigned_value <= BACNET_MAX_INSTANCE) {
data->high_limit = unsigned_value;
}
}
}
}
} else {
data->low_limit = -1;
data->high_limit = -1;
}
/* object id */
if (decode_is_context_tag(&apdu[len], 2)) {
data->is_object_name = false;
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
len += decode_object_id(
&apdu[len], &decoded_type, &data->object.identifier.instance);
data->object.identifier.type = decoded_type;
}
/* object name */
else if (decode_is_context_tag(&apdu[len], 3)) {
data->is_object_name = true;
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
len += decode_character_string(
&apdu[len], len_value, &data->object.name);
}
/* missing required parameters */
else {
if ((unsigned)len < apdu_len) {
if (decode_is_context_tag(&apdu[len], 2)) {
data->is_object_name = false;
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
if ((unsigned)len < apdu_len) {
len += decode_object_id(
&apdu[len], &decoded_type, &data->object.identifier.instance);
data->object.identifier.type = decoded_type;
}
}
/* object name */
else if (decode_is_context_tag(&apdu[len], 3)) {
data->is_object_name = true;
len += decode_tag_number_and_value(
&apdu[len], &tag_number, &len_value);
if ((unsigned)len < apdu_len) {
len += decode_character_string(
&apdu[len], len_value, &data->object.name);
}
} else {
/* missing required parameters */
return -1;
}
} else {
/* message too short */
return -1;
}
}