linuxptp/fd.h

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/**
* @file fd.h
* @brief Defines a array of file descriptors, useful for polling.
* @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef HAVE_FD_H
#define HAVE_FD_H
#define N_TIMER_FDS 8
Fix crash in hybrid E2E mode. Richard Hill reported an occasional NULL pointer deference in port_delay_request() when in hybrid mode. if (p->hybrid_e2e) { struct ptp_message *dst = TAILQ_FIRST(&p->best->messages); msg->address = dst->address; ... } The code assumes that the p->best->messages list can't be empty because: The function, port_delay_request(), is called only when FD_DELAY_TIMER expires. That timer is only set by the function, port_set_delay_tmo(), which is called: 1. from process_delay_resp(), but only when state is UNCALIBRATED or SLAVE. 2. from port_e2e_transition(), but only when state is UNCALIBRATED or SLAVE. Looking at handle_state_decision_event(), a port can only enter UNCALIBRATED or SLAVE when it has a valid foreign master record, ie p->best->messages is not null. A port also only clears p->best->messages when it leaves UNCALIBRATED or SLAVE, at which point the FD_DELAY_TIMER is also cleared. *However* the p->best->messages list *can* be empty if the FD_ANNOUNCE_TIMER and the FD_DELAY_TIMER expire at the same time. In this case, the poll() call indicates events on both file descriptors. The announce timeout is handled like this: case FD_ANNOUNCE_TIMER: case FD_SYNC_RX_TIMER: if (p->best) fc_clear(p->best); So then the port_delay_request() call de-references the null TAILQ_FIRST message pointer. This patch fixes the issue by re-ordering the timer file descriptors within the polling list. Signed-off-by: Richard Cochran <richardcochran@gmail.com> Reported-by: Richard Hill <plonta@gmx.de>
2018-05-16 21:44:56 +08:00
/*
* The order matters here. The DELAY timer must appear before the
* ANNOUNCE and SYNC_RX timers in order to correctly handle the case
* when the DELAY timer and one of the other two expire during the
* same call to poll().
*/
enum {
FD_EVENT,
FD_GENERAL,
Fix crash in hybrid E2E mode. Richard Hill reported an occasional NULL pointer deference in port_delay_request() when in hybrid mode. if (p->hybrid_e2e) { struct ptp_message *dst = TAILQ_FIRST(&p->best->messages); msg->address = dst->address; ... } The code assumes that the p->best->messages list can't be empty because: The function, port_delay_request(), is called only when FD_DELAY_TIMER expires. That timer is only set by the function, port_set_delay_tmo(), which is called: 1. from process_delay_resp(), but only when state is UNCALIBRATED or SLAVE. 2. from port_e2e_transition(), but only when state is UNCALIBRATED or SLAVE. Looking at handle_state_decision_event(), a port can only enter UNCALIBRATED or SLAVE when it has a valid foreign master record, ie p->best->messages is not null. A port also only clears p->best->messages when it leaves UNCALIBRATED or SLAVE, at which point the FD_DELAY_TIMER is also cleared. *However* the p->best->messages list *can* be empty if the FD_ANNOUNCE_TIMER and the FD_DELAY_TIMER expire at the same time. In this case, the poll() call indicates events on both file descriptors. The announce timeout is handled like this: case FD_ANNOUNCE_TIMER: case FD_SYNC_RX_TIMER: if (p->best) fc_clear(p->best); So then the port_delay_request() call de-references the null TAILQ_FIRST message pointer. This patch fixes the issue by re-ordering the timer file descriptors within the polling list. Signed-off-by: Richard Cochran <richardcochran@gmail.com> Reported-by: Richard Hill <plonta@gmx.de>
2018-05-16 21:44:56 +08:00
FD_DELAY_TIMER,
FD_ANNOUNCE_TIMER,
FD_SYNC_RX_TIMER,
FD_QUALIFICATION_TIMER,
FD_MANNO_TIMER,
FD_SYNC_TX_TIMER,
FD_UNICAST_REQ_TIMER,
FD_UNICAST_SRV_TIMER,
FD_RTNL,
N_POLLFD,
};
Fix crash in hybrid E2E mode. Richard Hill reported an occasional NULL pointer deference in port_delay_request() when in hybrid mode. if (p->hybrid_e2e) { struct ptp_message *dst = TAILQ_FIRST(&p->best->messages); msg->address = dst->address; ... } The code assumes that the p->best->messages list can't be empty because: The function, port_delay_request(), is called only when FD_DELAY_TIMER expires. That timer is only set by the function, port_set_delay_tmo(), which is called: 1. from process_delay_resp(), but only when state is UNCALIBRATED or SLAVE. 2. from port_e2e_transition(), but only when state is UNCALIBRATED or SLAVE. Looking at handle_state_decision_event(), a port can only enter UNCALIBRATED or SLAVE when it has a valid foreign master record, ie p->best->messages is not null. A port also only clears p->best->messages when it leaves UNCALIBRATED or SLAVE, at which point the FD_DELAY_TIMER is also cleared. *However* the p->best->messages list *can* be empty if the FD_ANNOUNCE_TIMER and the FD_DELAY_TIMER expire at the same time. In this case, the poll() call indicates events on both file descriptors. The announce timeout is handled like this: case FD_ANNOUNCE_TIMER: case FD_SYNC_RX_TIMER: if (p->best) fc_clear(p->best); So then the port_delay_request() call de-references the null TAILQ_FIRST message pointer. This patch fixes the issue by re-ordering the timer file descriptors within the polling list. Signed-off-by: Richard Cochran <richardcochran@gmail.com> Reported-by: Richard Hill <plonta@gmx.de>
2018-05-16 21:44:56 +08:00
#define FD_FIRST_TIMER FD_DELAY_TIMER
struct fdarray {
int fd[N_POLLFD];
};
#endif