[Bug 255495] udp socket inheritance after fork+exec

[b***@freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255495

Bug ID: 255495
Summary: udp socket inheritance after fork+exec
Product: Base System
Version: 12.2-STABLE
Hardware: Any
OS: Any
Status: New
Severity: Affects Some People
Priority: ---
Component: kern
Assignee: ***@FreeBSD.org
Reporter: ***@freebsd.org
CC: ***@FreeBSD.org, ***@FreeBSD.org

I observe the following unexpected behaviour while running both net/frr7 and
net/mpd5 within same 12.2-STABLE/amd64 system. After boot, it runs just fine:

# sockstat | fgrep frr
frr staticd 37908 6 dgram -> /var/run/logpriv
frr staticd 37908 10 stream -> /var/run/frr/zserv.api
frr staticd 37908 11 stream /var/run/frr/staticd.vty
frr ospfd 37903 6 dgram -> /var/run/logpriv
frr ospfd 37903 10 stream -> /var/run/frr/zserv.api
frr ospfd 37903 11 stream /var/run/frr/ospfd.vty
frr zebra 37898 6 dgram -> /var/run/logpriv
frr zebra 37898 18 stream /var/run/frr/zserv.api
frr zebra 37898 21 stream /var/run/frr/zebra.vty
frr zebra 37898 23 stream /var/run/frr/zserv.api
frr zebra 37898 28 stream /var/run/frr/zserv.api

# sockstat | fgrep mpd5 | fgrep udp4
root mpd5 26675 26 udp4 *:1701 *:*

That is, mpd5 expects incoming L2TP connections at port udp/1701 and frr7
daemon do not use any UDP sockets, as configured.

The mpd5 daemon has ip-down/ip-up scripts that may do "service frr stop" and
"service frr start" in come cases, so frr7 daemons may be started as
grandchildren of mpd5 process. After that, I observe this:

# sockstat | fgrep frr
frr staticd 40712 6 dgram -> /var/run/logpriv
frr staticd 40712 12 stream -> /var/run/frr/zserv.api
frr staticd 40712 13 stream /var/run/frr/staticd.vty
frr staticd 40712 26 udp4 *:1701 *:*
frr ospfd 40707 6 dgram -> /var/run/logpriv
frr ospfd 40707 12 stream -> /var/run/frr/zserv.api
frr ospfd 40707 13 stream /var/run/frr/ospfd.vty
frr ospfd 40707 26 udp4 *:1701 *:*
frr zebra 40702 6 dgram -> /var/run/logpriv
frr zebra 40702 24 stream /var/run/frr/zserv.api
frr zebra 40702 25 stream /var/run/frr/zebra.vty
frr zebra 40702 26 udp4 *:1701 *:*
frr zebra 40702 30 stream /var/run/frr/zserv.api
frr zebra 40702 35 stream /var/run/frr/zserv.api

frr daemons somehow inherit udp4/1501 socket and that is bad for local L2TP
service, it is broken now.

[b***@freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255495

Eugene Grosbein <***@freebsd.org> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|New |Closed
Resolution|--- |Works As Intended

--- Comment #1 from Eugene Grosbein <***@freebsd.org> ---
Sorry for noise, the problem is not in FreeBSD kernel but in the net/mpd5
daemon itself.

[b***@freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=255495

Kubilay Kocak <***@FreeBSD.org> changed:

What |Removed |Added
----------------------------------------------------------------------------
Assignee|***@FreeBSD.org |***@freebsd.org
Resolution|Works As Intended |Not A Bug

--- Comment #2 from Kubilay Kocak <***@FreeBSD.org> ---
^Triage: Assign to committer that resolved. Correct resolution