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[libbacnet]: bacapp_data_len() + bacnet_tag_number_and_value_decode() (#453)

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* Bugfix: bacapp_data_len() + bacnet_tag_number_and_value_decode()

* Fix bacnet_tag_number_and_value_decode function.
Add read buffer safe functions for opening, closing, context specific tags.
Fix bacapp_data_len function changes as indicated by unit testing.

* refactor bacapp_data_len
---------
Co-authored-by: Steve Karg <skarg@users.sourceforge.net>
This commit is contained in:
anthony-crystalpeak
2023-07-31 14:50:14 -07:00
committed by GitHub
parent 28de333b6e
commit acb3b0f57d
4 changed files with 134 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/bacnet/bacapp.c
+54 -37
View File
@@ -1520,54 +1520,71 @@ int bacapp_data_len(
uint8_t opening_tag_number = 0;
uint8_t opening_tag_number_counter = 0;
uint32_t value = 0;
bool total_len_enable = false;
if (IS_OPENING_TAG(apdu[0])) {
len = bacnet_tag_number_and_value_decode(
&apdu[apdu_len], apdu_len_max - apdu_len, &tag_number, &value);
apdu_len += len;
opening_tag_number = tag_number;
opening_tag_number_counter = 1;
while (opening_tag_number_counter) {
if (IS_OPENING_TAG(apdu[apdu_len])) {
len = bacnet_tag_number_and_value_decode(&apdu[apdu_len],
apdu_len_max - apdu_len, &tag_number, &value);
if (tag_number == opening_tag_number) {
opening_tag_number_counter++;
}
} else if (IS_CLOSING_TAG(apdu[apdu_len])) {
len = bacnet_tag_number_and_value_decode(&apdu[apdu_len],
apdu_len_max - apdu_len, &tag_number, &value);
if (tag_number == opening_tag_number) {
if (!apdu) {
return BACNET_STATUS_ERROR;
}
if (apdu_len_max <= apdu_len) {
/* error: exceeding our buffer limit */
return BACNET_STATUS_ERROR;
}
if (!bacnet_is_opening_tag(apdu, apdu_len_max)) {
/* error: opening tag is missing */
return BACNET_STATUS_ERROR;
}
do {
if (bacnet_is_opening_tag(apdu, apdu_len_max)) {
len = bacnet_tag_number_and_value_decode(apdu,
apdu_len_max - apdu_len, &tag_number, &value);
if (opening_tag_number_counter == 0) {
opening_tag_number = tag_number;
opening_tag_number_counter = 1;
total_len_enable = false;
} else if (tag_number == opening_tag_number) {
total_len_enable = true;
opening_tag_number_counter++;
}
} else if (bacnet_is_closing_tag(apdu, apdu_len_max)) {
len = bacnet_tag_number_and_value_decode(apdu,
apdu_len_max - apdu_len, &tag_number, &value);
if (tag_number == opening_tag_number) {
if (opening_tag_number_counter > 0) {
opening_tag_number_counter--;
}
} else if (IS_CONTEXT_SPECIFIC(apdu[apdu_len])) {
}
total_len_enable = true;
} else if (bacnet_is_context_specific(apdu, apdu_len_max)) {
#if defined(BACAPP_TYPES_EXTRA)
/* context-specific tagged data */
len = bacapp_decode_context_data_len(
&apdu[apdu_len], apdu_len_max - apdu_len, property);
/* context-specific tagged data */
len = bacapp_decode_context_data_len(
apdu, apdu_len_max - apdu_len, property);
total_len_enable = true;
#endif
} else {
/* application tagged data */
len = bacapp_decode_application_data_len(
apdu, apdu_len_max - apdu_len);
total_len_enable = true;
}
if (opening_tag_number_counter > 0) {
if (len > 0) {
if (total_len_enable) {
total_len += len;
}
} else {
/* application tagged data */
len = bacapp_decode_application_data_len(
&apdu[apdu_len], apdu_len_max - apdu_len);
/* error: len is not incrementing */
return BACNET_STATUS_ERROR;
}
apdu_len += len;
if (opening_tag_number_counter) {
if (len > 0) {
total_len += len;
} else {
/* error: len is not incrementing */
total_len = BACNET_STATUS_ERROR;
break;
}
}
if ((unsigned)apdu_len > apdu_len_max) {
if (apdu_len_max <= apdu_len) {
/* error: exceeding our buffer limit */
total_len = BACNET_STATUS_ERROR;
break;
return BACNET_STATUS_ERROR;
}
apdu += len;
}
}
} while (opening_tag_number_counter > 0);
return total_len;
}
src/bacnet/bacdcode.c
+71 -9
View File
@@ -457,6 +457,27 @@ bool decode_is_opening_tag(uint8_t *apdu)
return (bool)((apdu[0] & 0x07) == 6);
}
/**
* @brief Returns true if an opening tag has been found.
*
* @param apdu Pointer to the tag number.
* @param apdu_size Number of bytes available to decode
*
* @return true if an opening tag has been found.
*/
bool bacnet_is_opening_tag(uint8_t *apdu, uint32_t apdu_size)
{
bool tag = false;
if (apdu_size > 0) {
if (IS_OPENING_TAG(apdu[0])) {
tag = true;
}
}
return tag;
}
/**
* @brief Returns if at the given pointer a
* closing tag has been found.
@@ -470,6 +491,49 @@ bool decode_is_closing_tag(uint8_t *apdu)
return (bool)((apdu[0] & 0x07) == 7);
}
/**
* @brief Returns true if a closing tag has been found.
*
* @param apdu Pointer to the tag number.
* @param apdu_size Number of bytes available to decode
*
* @return true if a closing tag has been found.
*/
bool bacnet_is_closing_tag(uint8_t *apdu, uint32_t apdu_size)
{
bool tag = false;
if (apdu_size > 0) {
if (IS_CLOSING_TAG(apdu[0])) {
tag = true;
}
}
return tag;
}
/**
* @brief Returns true if a context specific tag has been found.
*
* @param apdu Pointer to the tag number.
* @param apdu_size Number of bytes available to decode
*
* @return true if a context specific tag has been found.
*/
bool bacnet_is_context_specific(uint8_t *apdu, uint32_t apdu_size)
{
bool tag = false;
if (apdu_size > 0) {
if (IS_CONTEXT_SPECIFIC(apdu[0])) {
tag = true;
}
}
return tag;
}
/**
* @brief Decodes the tag number and the value,
* that the APDU pointer is addressing.
@@ -549,28 +613,26 @@ int bacnet_tag_number_and_value_decode(
len = bacnet_tag_number_decode(&apdu[0], apdu_len_max, tag_number);
if (len > 0) {
apdu_len_max -= len;
if (IS_EXTENDED_VALUE(apdu[0])) {
/* tagged as uint32_t */
if (IS_EXTENDED_VALUE(apdu[0]) && (apdu_len_max > len)) {
apdu_len_max -= len;
if ((apdu[len] == 255) && (apdu_len_max >= 5)) {
/* tagged as uint32_t */
uint32_t value32;
len++;
len += decode_unsigned32(&apdu[len], &value32);
if (value) {
*value = value32;
}
}
/* tagged as uint16_t */
else if ((apdu[len] == 254) && (apdu_len_max >= 3)) {
} else if ((apdu[len] == 254) && (apdu_len_max >= 3)) {
/* tagged as uint16_t */
uint16_t value16;
len++;
len += decode_unsigned16(&apdu[len], &value16);
if (value) {
*value = value16;
}
}
/* no tag - must be uint8_t */
else if ((apdu[len] < 254) && (apdu_len_max >= 1)) {
} else if ((apdu[len] < 254) && (apdu_len_max >= 1)) {
/* no tag - must be uint8_t */
if (value) {
*value = apdu[len];
}
src/bacnet/bacdcode.h
+7
View File
@@ -61,6 +61,13 @@ extern "C" {
bool context_specific,
uint32_t len_value_type);
BACNET_STACK_EXPORT
bool bacnet_is_opening_tag(uint8_t *apdu, uint32_t apdu_size);
BACNET_STACK_EXPORT
bool bacnet_is_closing_tag(uint8_t *apdu, uint32_t apdu_size);
BACNET_STACK_EXPORT
bool bacnet_is_context_specific(uint8_t *apdu, uint32_t apdu_size);
/* from clause 20.2.1.3.2 Constructed Data */
/* returns the number of apdu bytes consumed */
BACNET_STACK_EXPORT
test/bacnet/wp/src/main.c
+2 -2
View File
@@ -61,11 +61,11 @@ static void testWritePropertyTag(BACNET_APPLICATION_DATA_VALUE *value)
wpdata.application_data_len =
bacapp_encode_application_data(&wpdata.application_data[0], value);
len = wp_encode_apdu(&apdu[0], invoke_id, &wpdata);
zassert_not_equal(len, 0, NULL);
zassert_not_equal(len, 0, "len=%d", len);
/* decode the data */
apdu_len = len;
len = wp_decode_apdu(&apdu[0], apdu_len, &test_invoke_id, &test_data);
zassert_not_equal(len, -1, NULL);
zassert_true(len > 0, "len=%d", len);
zassert_equal(test_data.object_type, wpdata.object_type, NULL);
zassert_equal(test_data.object_instance, wpdata.object_instance, NULL);
zassert_equal(test_data.object_property, wpdata.object_property, NULL);