Question

psApdu->prgbCData = (byte_t*)malloc(APDU_BUFFER_LENGTH);
memset((void*)psApdu->prgbCData, 0, APDU_BUFFER_LENGTH);

byte_t prgData[] = { 0x01, 0x38, 0x00, 0x04, 0x00, 0x00, 0x00, 0x02 };
memcpy((byte*)psApdu->prgbCData, prgData, sizeof(prgData));

free(psApdu->prgbCData);

‘free’ statement failing here. What is the reason?

Answer 1

Firstly, you shouldn’t cast to and from void *. Also sizeof is an operator.

You need to check that sizeof prgData <= APDU_BUFFER_LENGTH. You could try this with a static assertion:

psApdu->prgbCData = malloc(APDU_BUFFER_LENGTH);
memset(psApdu->prgbCData, 0, APDU_BUFFER_LENGTH);

byte_t prgData[] = { 0x01, 0x38, 0x00, 0x04, 0x00, 0x00, 0x00, 0x02 };
_Static_assert(sizeof prgData <= APDU_BUFFER_LENGTH, "too big");
memcpy(psApdu->prgbCData, prgData, sizeof prgData);

free(psApdu->prgbCData);