Messages in this thread | | | From | Jürg Billeter <> | Subject | [RESEND PATCH v2 0/1] Add prctl to kill descendants on exit | Date | Fri, 18 Jan 2019 14:11:29 +0100 |
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This patch adds a new prctl to kill all descendant processes on exit. See commit message for details of the prctl.
This is a replacement of PR_SET_PDEATHSIG_PROC I proposed last year [1]. In the following discussion, Oleg suggested this approach.
The motivation for this is to provide a lightweight mechanism to prevent stray processes. There is also a related Bugzilla entry [2].
PID namespaces can also be used to prevent stray processes, of course. However, they are not quite as lightweight as they typically also require a new mount namespace to be able to mount a new /proc. And they require CAP_SYS_ADMIN. User namespaces can help to gain CAP_SYS_ADMIN, however, that further increases the overhead and the other effects of the user namespace may not be desired.
PID 1 in PID namespaces also exhibits non-standard signal behavior (SIGNAL_UNKILLABLE) [3].
Changes in v2: - Use bool instead of bitfield to avoid race with PR_SET_CHILD_SUBREAPER
[1] https://lkml.kernel.org/lkml/20170929123058.48924-1-j@bitron.ch/ [2] https://bugzilla.kernel.org/show_bug.cgi?id=43300 [3] https://lkml.kernel.org/lkml/20180803144021.56920-2-j@bitron.ch/
Jürg Billeter (1): prctl: add PR_{GET,SET}_KILL_DESCENDANTS_ON_EXIT
fs/exec.c | 6 ++++++ include/linux/sched/signal.h | 3 +++ include/uapi/linux/prctl.h | 4 ++++ kernel/exit.c | 12 ++++++++++++ kernel/sys.c | 11 +++++++++++ security/apparmor/lsm.c | 1 + security/selinux/hooks.c | 3 +++ 7 files changed, 40 insertions(+)
-- 2.20.1
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