ssh_packet_send1(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	u_char buf[8], *cp;
	int r, padding, len;
	u_int checksum;

	/*
	 * If using packet compression, compress the payload of the outgoing
	 * packet.
	 */
	if (state->packet_compression) {
		sshbuf_reset(state->compression_buffer);
		/* Skip padding. */
		if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0)
			goto out;
		/* padding */
		if ((r = sshbuf_put(state->compression_buffer,
		    "\0\0\0\0\0\0\0\0", 8)) != 0)
			goto out;
		if ((r = compress_buffer(ssh, state->outgoing_packet,
		    state->compression_buffer)) != 0)
			goto out;
		sshbuf_reset(state->outgoing_packet);
                if ((r = sshbuf_putb(state->outgoing_packet,
                    state->compression_buffer)) != 0)
			goto out;
	}
	/* Compute packet length without padding (add checksum, remove padding). */
	len = sshbuf_len(state->outgoing_packet) + 4 - 8;

	/* Insert padding. Initialized to zero in packet_start1() */
	padding = 8 - len % 8;
	if (!state->send_context.plaintext) {
		cp = sshbuf_mutable_ptr(state->outgoing_packet);
		if (cp == NULL) {
			r = SSH_ERR_INTERNAL_ERROR;
			goto out;
		}
		arc4random_buf(cp + 8 - padding, padding);
	}
	if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0)
		goto out;

	/* Add check bytes. */
	checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet),
	    sshbuf_len(state->outgoing_packet));
	POKE_U32(buf, checksum);
	if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0)
		goto out;

#ifdef PACKET_DEBUG
	fprintf(stderr, "packet_send plain: ");
	sshbuf_dump(state->outgoing_packet, stderr);
#endif

	/* Append to output. */
	POKE_U32(buf, len);
	if ((r = sshbuf_put(state->output, buf, 4)) != 0)
		goto out;
	if ((r = sshbuf_reserve(state->output,
	    sshbuf_len(state->outgoing_packet), &cp)) != 0)
		goto out;
	if ((r = cipher_crypt(&state->send_context, 0, cp,
	    sshbuf_ptr(state->outgoing_packet),
	    sshbuf_len(state->outgoing_packet), 0, 0)) != 0)
		goto out;

#ifdef PACKET_DEBUG
	fprintf(stderr, "encrypted: ");
	sshbuf_dump(state->output, stderr);
#endif
	state->p_send.packets++;
	state->p_send.bytes += len +
	    sshbuf_len(state->outgoing_packet);
	sshbuf_reset(state->outgoing_packet);

	/*
	 * Note that the packet is now only buffered in output.  It won't be
	 * actually sent until ssh_packet_write_wait or ssh_packet_write_poll
	 * is called.
	 */
	r = 0;
 out:
	return r;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.