Function read_sum_head

io.c:2025–2067

Populate a sum_struct with values from the socket. This is * called by both the sender and the receiver. */

/* Populate a sum_struct with values from the socket.  This is
 * called by both the sender and the receiver. */
void read_sum_head(int f, struct sum_struct *sum)
{
	int32 max_blength = protocol_version < 30 ? OLD_MAX_BLOCK_SIZE : MAX_BLOCK_SIZE;
	sum->count = read_int(f);
	if (sum->count < 0) {
		rprintf(FERROR, "Invalid checksum count %ld [%s]\n",
			(long)sum->count, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
	/* Guard against integer overflow in downstream allocations sized by
	 * count*element_size. my_alloc uses divide-not-multiply so it is
	 * already wraparound-safe, but checking here gives a clearer error
	 * and also covers the (size_t)count * xfer_sum_len arithmetic that
	 * is performed *before* reaching my_alloc. */
	if (xfer_sum_len > 0 && (size_t)sum->count > SIZE_MAX / (size_t)xfer_sum_len) {
		rprintf(FERROR, "Invalid checksum count %ld (too large) [%s]\n",
			(long)sum->count, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
	if ((size_t)sum->count > SIZE_MAX / sizeof(struct sum_buf)) {
		rprintf(FERROR, "Invalid checksum count %ld (sum_buf overflow) [%s]\n",
			(long)sum->count, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
	sum->blength = read_int(f);
	if (sum->blength < 0 || sum->blength > max_blength) {
		rprintf(FERROR, "Invalid block length %ld [%s]\n",
			(long)sum->blength, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
	sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
	if (sum->s2length < 0 || sum->s2length > xfer_sum_len) {
		rprintf(FERROR, "Invalid checksum length %d [%s]\n",
			sum->s2length, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
	sum->remainder = read_int(f);
	if (sum->remainder < 0 || sum->remainder > sum->blength) {
		rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
			(long)sum->remainder, who_am_i());
		exit_cleanup(RERR_PROTOCOL);
	}
}

/* Send the values from a sum_struct over the socket.  Set sum to
 * NULL if there are no checksums to send.  This is called by both