Due to the fact that the init is implemented in Go (which seemingly
randomly spawns new processes and loves eating memory), most cgroup
configurations are required to have an arbitrary minimum dictated by the
init. This confuses users and makes configuration more annoying than it
should. An example of this is pids.max, where Go spawns multiple
processes that then cause init to violate the pids cgroup constraint
before the container can even start.
Solve this problem by setting the cgroup configurations as late as
possible, to avoid hitting as many of the resources hogged by the Go
init as possible. This has to be done before seccomp rules are applied,
as the parent and child must synchronise in order for the parent to
correctly set the configurations (and writes might be blocked by seccomp).
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Whenever dev/null is used as one of the main processes STDIO, do not try
to change the permissions on it via fchown because we should not do it
in the first place and also this will fail if the container is supposed
to be readonly.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Fix the permissions of the container's main processes STDIO when the
process is not run as the root user. This changes the permissions right
before switching to the specified user so that it's STDIO matches it's
UID and GID.
Add a test for checking that the STDIO of the process is owned by the
specified user.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This removes the existing, native Go seccomp filter generation and replaces it
with Libseccomp. Libseccomp is a C library which provides architecture
independent generation of Seccomp filters for the Linux kernel.
This adds a dependency on v2.2.1 or above of Libseccomp.
Signed-off-by: Matthew Heon <mheon@redhat.com>
Aleksa Sarai
Michael Crosby
Alexander Morozov
Vishnu Kannan
Matthew Heon
Jin-Hwan Jeong