2011-11-06 15:16:19 +08:00
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/**
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* @file fd.h
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* @brief Defines a array of file descriptors, useful for polling.
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* @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef HAVE_FD_H
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#define HAVE_FD_H
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2013-08-26 20:25:58 +08:00
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#define N_TIMER_FDS 6
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2011-12-27 21:35:35 +08:00
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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
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/*
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* The order matters here. The DELAY timer must appear before the
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* ANNOUNCE and SYNC_RX timers in order to correctly handle the case
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* when the DELAY timer and one of the other two expire during the
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* same call to poll().
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*/
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2011-11-06 15:16:19 +08:00
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enum {
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FD_EVENT,
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FD_GENERAL,
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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
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FD_DELAY_TIMER,
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2011-11-06 15:16:19 +08:00
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FD_ANNOUNCE_TIMER,
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2013-08-26 20:25:58 +08:00
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FD_SYNC_RX_TIMER,
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2011-12-27 18:54:08 +08:00
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FD_QUALIFICATION_TIMER,
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2011-12-27 21:35:35 +08:00
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FD_MANNO_TIMER,
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2013-08-26 19:33:37 +08:00
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FD_SYNC_TX_TIMER,
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2017-07-10 15:39:29 +08:00
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FD_RTNL,
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2011-11-06 15:16:19 +08:00
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N_POLLFD,
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};
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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
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#define FD_FIRST_TIMER FD_DELAY_TIMER
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2011-11-06 15:16:19 +08:00
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struct fdarray {
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int fd[N_POLLFD];
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};
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#endif
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