seccomp: move generation out of cgroup and do not fail on unknown syscalls #211
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Needs rebase. |
rhatdan
reviewed
Dec 17, 2019
generate the seccomp profile in the parent process, not from init while running with cgroups configured. The reason is that seccomp generation might require more memory than it is configured in the cgroups. crun memory consumption is more predictable now, and can run with less than 500Kb of memory in the cgroup (I've tested that it runs reliably with 250Kb and never hit any OOM). Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
when a syscall that is not known to libseccomp is specified, ignore it instead of failing. It makes easier to use newer seccomp policies on systems using an older libseccomp. It is possible to keep the previous behavior using the "run.oci.seccomp_fail_unknown_syscall=1" annotation. Closes: containers#156 Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
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@giuseppe Could you fix the issue that @haircommander pointed out in this PR. |
| int libcrun_generate_and_load_seccomp (libcrun_container_t *container, int outfd, char **flags, size_t flags_len, libcrun_error_t *err); | ||
| enum | ||
| { | ||
| LIBCRUN_SECCOMP_FAIL_UNKNOWN_SYSCALL = 1 << 0, |
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why shift by 0? or am I misreading here
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no misreading, it is really a shift by 0 :-) It is a nop but it makes clear it is a bitmask
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LGTM |
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two separate changes I've put together on the same PR to avoid rebasing:
The first one is to move seccomp generation out of the init process. It improves memory usage for the init process and now containers (assuming the init process doesn't need more) can run with 250K memory max configured in the cgroup.
The second one is to not fail on unknown syscalls specified to seccomp. An annotation is added too keep the previous behaviour.
More details are in the commit messages.
Signed-off-by: Giuseppe Scrivano gscrivan@redhat.com