[Linuxptp-devel] [PATCH] timemaster: set mode in ntp config to create private SHM segments.

[Miroslav Lichvar]

In ntp-4.2.8p1 the segment access was made configurable with the
refclock mode option. Set the mode to 1 to create all SHM segments
with owner-only access.
---
timemaster.8 | 10 ++++++----
timemaster.c | 3 ++-
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/timemaster.8 b/timemaster.8
index 9a3ddb4..062322b 100644
--- a/timemaster.8
+++ b/timemaster.8
@@ -250,10 +250,12 @@ for PTP sources (\fBntp_poll\fR) to specify a subsecond interval.
The \fBntpd\fR limitations are:

.RS
-Only the first two shared-memory segments created by the SHM refclock driver
-in \fBntpd\fR have owner-only access. Other segments are created with world
-access, possibly allowing any user on the system writing to the segments and
-disrupting the synchronization.
+In versions before 4.2.8p1, only the first two shared-memory segments created by
+the \fBntpd\fR SHM refclock driver have owner-only access. Other segments
+are created with world access, which allows any user on the system to write to
+the segments and disrupt or take control over the synchronization of the clock.
+In 4.2.8p1 the access was made configurable with the mode option, which is set
+by \fBtimemaster\fR for owner-ownly access.

The shortest polling interval for all sources is 3 (8 seconds).

diff --git a/timemaster.c b/timemaster.c
index 83a5b83..eec0d0d 100644
--- a/timemaster.c
+++ b/timemaster.c
@@ -623,7 +623,8 @@ static void add_shm_source(int shm_segment, int poll, int dpoll, double delay,
break;
case NTPD:
string_appendf(ntp_config,
- "server 127.127.28.%d minpoll %d maxpoll %d\n"
+ "server 127.127.28.%d minpoll %d maxpoll %d "
+ "mode 1\n"
"fudge 127.127.28.%d refid %s\n",
shm_segment, poll, poll, shm_segment, refid);
break;

[Richard Cochran]

Post by Miroslav Lichvar
In ntp-4.2.8p1 the segment access was made configurable with the
refclock mode option. Set the mode to 1 to create all SHM segments
with owner-only access.

Applied.

Thanks,
Richard