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systemd-stable/sysctl.d/50-coredump.conf.in

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journal: hook up coredumping with journal
2012-01-14 03:37:35 +04:00
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
relicense to LGPLv2.1 (with exceptions) We finally got the OK from all contributors with non-trivial commits to relicense systemd from GPL2+ to LGPL2.1+. Some udev bits continue to be GPL2+ for now, but we are looking into relicensing them too, to allow free copy/paste of all code within systemd. The bits that used to be MIT continue to be MIT. The big benefit of the relicensing is that closed source code may now link against libsystemd-login.so and friends.
2012-04-12 02:20:58 +04:00
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
journal: hook up coredumping with journal
2012-01-14 03:37:35 +04:00
# (at your option) any later version.
sysctl: enable coredump for suid binaries Right now the kernel will not dump anything that went through setuid or setgid. But it is routine for daemons to do that, and it makes things hard to debug. systemd-coredump saves the coredump readable by the users the process was running as. This should be enough to avoid information leakage. So let's also tell the kernel to do the coredump. For https://bugzilla.redhat.com/show_bug.cgi?id=1790972. Both patterns are stored in the same file, so they are enabled or disabled together. (Though suid_dumpable=2 is supposed to be safe even when writing to plain files.)
2020-04-03 23:05:25 +03:00
# See sysctl.d(5) for the description of the files in this directory.
journal: hook up coredumping with journal
2012-01-14 03:37:35 +04:00
sysctl: enable coredump for suid binaries Right now the kernel will not dump anything that went through setuid or setgid. But it is routine for daemons to do that, and it makes things hard to debug. systemd-coredump saves the coredump readable by the users the process was running as. This should be enough to avoid information leakage. So let's also tell the kernel to do the coredump. For https://bugzilla.redhat.com/show_bug.cgi?id=1790972. Both patterns are stored in the same file, so they are enabled or disabled together. (Though suid_dumpable=2 is supposed to be safe even when writing to plain files.)
2020-04-03 23:05:25 +03:00
# Pipe the core file to systemd-coredump. The systemd-coredump process spawned
# by the kernel will start a second copy of itself as the
# systemd-coredump@.service, which will do the actual processing and storing of
# the core dump.
#
# See systemd-coredump(8) and core(5).
coredump: rely on /proc exclusively to get the name of the crashing process I couldn't see any reason why the kernel could provide COMM to the coredump handler via the core_pattern command line but could not make it available in /proc. So let's assume that this info is always available in /proc. For "backtrace" mode (when --backtrace option is passed), I assumed that the crashing process still exists at the time systemd-coredump is called. Also changing the core_pattern line is an API breakage for any users of the backtrace mode but given that systemd-coredump is installed in /usr/lib/systemd, it's a private tool which has no internal users. At least no one complained when the hostname was added to the core_pattern line (f45b8015513)... Indeed it's much easier to get it from /proc since the kernel substitutes '%e' specifier with multiple strings if the process name contains spaces (!).
2019-06-21 14:12:41 +03:00
kernel.core_pattern=|@rootlibexecdir@/systemd-coredump %P %u %g %s %t %c %h
sysctl: enable coredump for suid binaries Right now the kernel will not dump anything that went through setuid or setgid. But it is routine for daemons to do that, and it makes things hard to debug. systemd-coredump saves the coredump readable by the users the process was running as. This should be enough to avoid information leakage. So let's also tell the kernel to do the coredump. For https://bugzilla.redhat.com/show_bug.cgi?id=1790972. Both patterns are stored in the same file, so they are enabled or disabled together. (Though suid_dumpable=2 is supposed to be safe even when writing to plain files.)
2020-04-03 23:05:25 +03:00
sysctl.d: shorten comment The grammar was a bit suspect in a few places...
2020-12-10 19:13:12 +03:00
# Allow 16 coredumps to be dispatched in parallel by the kernel.
# We collect metadata from /proc/%P/, and thus need to make sure the crashed
# processes are not reaped until we have finished collecting what we need. The
# kernel default for this sysctl is "0" which means the kernel doesn't wait for
# userspace to finish processing before reaping the crashed processes. With a
# higher setting the kernel will delay reaping until we are done, but only for
# the specified number of crashes in parallel. The value of 16 is chosen to
# match systemd-coredump.socket's MaxConnections= value.
sysctl: set kernel.core_pipe_limit=16 We need to make sure that our coredump pattern handler manages to read process metadata from /proc/$PID/ before the kernel reaps the crashed process. By default the kernel will reap the process as soon as it can. By setting kernel.core_pipe_limit to a non-zero the kernel will wait for userspace to finish before reaping. We'll set the value to 16, which allows 16 crashes to be processed in parallel. This matches the MaxConnections= setting in systemd-coredump.socket. See: #17301 (This doesn't close 17301, since we probably should also gracefully handle if /proc/$PID/ vanished already while our coredump handler runs, just in case people loclly set the sysctl back to zero. i.e. we should collect what we can and rather issue an incomplete log record than none.)
2020-10-12 17:31:42 +03:00
kernel.core_pipe_limit=16
sysctl: enable coredump for suid binaries Right now the kernel will not dump anything that went through setuid or setgid. But it is routine for daemons to do that, and it makes things hard to debug. systemd-coredump saves the coredump readable by the users the process was running as. This should be enough to avoid information leakage. So let's also tell the kernel to do the coredump. For https://bugzilla.redhat.com/show_bug.cgi?id=1790972. Both patterns are stored in the same file, so they are enabled or disabled together. (Though suid_dumpable=2 is supposed to be safe even when writing to plain files.)
2020-04-03 23:05:25 +03:00
# Also dump processes executing a set-user-ID/set-group-ID program that is
# owned by a user/group other than the real user/group ID of the process, or
# a program that has file capabilities. ("2" is called "suidsafe" in core(5)).
#
# systemd-coredump will store the core file owned by the effective uid and gid
# of the running process (and not the filesystem-user-ID which the kernel uses
# when saving a core dump).
#
# See proc(5), setuid(2), capabilities(7).
fs.suid_dumpable=2
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