Add libspdm_parse_measurement_transaction_data function

[pboyd04]

Fixes #3566

[steven-bellock]

Core libspdm libraries do not dynamically allocate memory. If memory is needed then it is provided by the API caller. See, for example, libspdm_get_certificate().

[ayj]

Question on how libspdm_parse_measurements_response should handle presence of signature.

[ayj]

Should the parser validate signature field presence or expected size? (Lines 237-241)

In libspdm_parse_measurements_response:

237:     if (signature_requested) {
238:         /* Signature is the last field. We do not need to know its size
239:          * since this must be the final response in the transcript. */
240:         *next_offset_out = data_size;
241:     }

While this helper only parses the transaction log structure and does not cryptographically verify the signature, if the input buffer is truncated right before the signature field (ptr == data_size at line 237), the function currently returns LIBSPDM_STATUS_SUCCESS.

• Should we add a check here to verify that the remaining buffer is non-empty (ptr < data_size) to ensure structural correctness?
• Or, since the VCA phase is walked at the start of the buffer, should we extract the negotiated measurement signature algorithm from the ALGORITHMS response to strictly validate that data_size - ptr == expected_signature_size?

[jyao1]

@pboyd04. allocate_pool() is NOT allowed in currently libspdm core library. Please fix it according to the feedback.