int rose_decode(struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
{
	unsigned char *frame;

	frame = skb->data;

	*ns = *nr = *q = *d = *m = 0;

	switch (frame[2]) {
	case ROSE_CALL_REQUEST:
	case ROSE_CALL_ACCEPTED:
	case ROSE_CLEAR_REQUEST:
	case ROSE_CLEAR_CONFIRMATION:
	case ROSE_RESET_REQUEST:
	case ROSE_RESET_CONFIRMATION:
		return frame[2];
	default:
		break;
	}

	if ((frame[2] & 0x1F) == ROSE_RR  ||
	    (frame[2] & 0x1F) == ROSE_RNR) {
		*nr = (frame[2] >> 5) & 0x07;
		return frame[2] & 0x1F;
	}

	if ((frame[2] & 0x01) == ROSE_DATA) {
		*q  = (frame[0] & ROSE_Q_BIT) == ROSE_Q_BIT;
		*d  = (frame[0] & ROSE_D_BIT) == ROSE_D_BIT;
		*m  = (frame[2] & ROSE_M_BIT) == ROSE_M_BIT;
		*nr = (frame[2] >> 5) & 0x07;
		*ns = (frame[2] >> 1) & 0x07;
		return ROSE_DATA;
	}

	return ROSE_ILLEGAL;
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.