debian/patches/fixes/0008-fix-signal-sending-in-lxc.init.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Tycho Andersen <tycho@tycho.ws>
   3 Date: Wed, 4 Apr 2018 17:45:29 -0600
   4 Subject: [PATCH] fix signal sending in lxc.init
   5
   6 The problem here is that these two clauses were ordered backwards: we first
   7 check if the signal came from not the init pid, and if it did, then we give
   8 a notice and return. The comment notes that this is intended to protect
   9 against SIGCHLD, but we don't in fact know if the signal is a SIGCHLD yet,
  10 because that's tested in the next hunk.
  11
  12 The symptom is that if I e.g. send SIGTERM from the outside world to the
  13 container init, it ignores it and gives this notice. If we re-order these
  14 clauses, it forwards non SIGCHLD signals, and ignores SIGCHLD signals from
  15 things that aren't the real container process.
  16
  17 Signed-off-by: Tycho Andersen <tycho@tycho.ws>
  18 ---
  19  src/lxc/start.c | 12 ++++++------
  20  1 file changed, 6 insertions(+), 6 deletions(-)
  21
  22 diff --git a/src/lxc/start.c b/src/lxc/start.c
  23 index ae13aae9..1982270e 100644
  24 --- a/src/lxc/start.c
  25 +++ b/src/lxc/start.c
  26 @@ -380,6 +380,12 @@ static int signal_handler(int fd, uint32_t events, void *data,
  27                 return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
  28         }
  29
  30 +       if (siginfo.ssi_signo != SIGCHLD) {
  31 +               kill(hdlr->pid, siginfo.ssi_signo);
  32 +               INFO("Forwarded signal %d to pid %d", siginfo.ssi_signo, hdlr->pid);
  33 +               return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
  34 +       }
  35 +
  36         /* More robustness, protect ourself from a SIGCHLD sent
  37          * by a process different from the container init.
  38          */
  39 @@ -389,12 +395,6 @@ static int signal_handler(int fd, uint32_t events, void *data,
  40                 return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
  41         }
  42
  43 -       if (siginfo.ssi_signo != SIGCHLD) {
  44 -               kill(hdlr->pid, siginfo.ssi_signo);
  45 -               INFO("Forwarded signal %d to pid %d", siginfo.ssi_signo, hdlr->pid);
  46 -               return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
  47 -       }
  48 -
  49         if (siginfo.ssi_code == CLD_STOPPED) {
  50                 INFO("Container init process was stopped");
  51                 return hdlr->init_died ? LXC_MAINLOOP_CLOSE : 0;
  52 --
  53 2.11.0
  54