On Fri, Sep 01, 2017 at 12:58:18PM +0200, Eduardo Otubo wrote: > 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. > +
This ought to be part of qemu-options.hx so it makes it into the qemu docs & man page. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
