Adding new documentation under docs/ to describe every one and each new option added by the refactoring patchset.
Signed-off-by: Eduardo Otubo <ot...@redhat.com> --- docs/seccomp.txt | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 docs/seccomp.txt diff --git a/docs/seccomp.txt b/docs/seccomp.txt new file mode 100644 index 0000000000..a5eca85a9b --- /dev/null +++ b/docs/seccomp.txt @@ -0,0 +1,31 @@ +QEMU Seccomp system call filter +=============================== + +Starting from QEMU version 2.11, the seccomp filter does not work as a +whitelist but as a blacklist instead. This method allows safer deploys since +only the strictly forbidden system calls will be black-listed and the +possibility of breaking any workload is close to zero. + +The default option (-sandbox on) has a slightly looser security though and the +reason is that it shouldn't break any backwards compatibility with previous +deploys and command lines already running. But if the intent is to have a +better security from this version on, one should make use of the following +additional options properly: + +* obsolete=allow|deny: It allows Qemu to run safely on old system that still + relies on old system calls. + +* elevateprivileges=allow|deny|children: It allows or denies Qemu process + to elevate its privileges by blacklisting all set*uid|gid system calls. The + 'children' option sets the PR_SET_NO_NEW_PRIVS to 1 which allows helpers + (forks and execs) to run unprivileged. + +* spawn=allow|deny: It blacklists fork and execve system calls, avoiding QEMU to + spawn new threads or processes. + +* resourcecontrol=allow|deny: It blacklists all process affinity and scheduler + priority system calls to avoid that the process can increase its amount of + allowed resource consumption. + +-- +Eduardo Otubo <ot...@redhat.com> -- 2.13.5
