[pve-devel] applied-series: [PATCH container 0/4] use seccomp proxy to handle mknod for

Thomas Lamprecht t.lamprecht at proxmox.com
Fri Jan 31 19:34:30 CET 2020

On 1/30/20 9:27 AM, Wolfgang Bumiller wrote:
> This series adds an `mknod` feature flag for unprivileged containers
> which is handled by setting `lxc.seccomp.proxy.notify` to point to the
> socket where pve-lxc-syscalld is listening (and `….proxy.cookie` to
> the vmid for possible future use).
> Currently the daemon handles `mknod()` with the following whitelist:
>     c:0:0 - whiteout
>     c:1:7 - /dev/full
>     c:1:3 - /dev/null
>     c:1:5 - /dev/zero
>     c:1:8 - /dev/random
>     c:1:9 - /dev/urandom
>     c:5:0 - /dev/tty
>     c:5:1 - /dev/console
> Currently the seccomp interface requires us to either completely
> handle a syscall or not catch it at all. (Iow. you can't just allow
> parts of a syscall manually and tell the kernel to "do its thing" for
> the cases you don't want to handle). For `mknod` this is not an issue
> since the kernel won't allow it at all in user namespaces.
> Later when we get a kernel >=5.5 we could also start partially
> handling some syscalls (eg. mount, but that'll only be feasable with
> the old mount api), and send cases we don't want to handle "back to the
> kernel".
> Wolfgang Bumiller (4):
>   add mknod feature flag
>   add a check_kernel_release helper
>   mask 'mknod' feature by kernel version
>   set lxc.seccomp.notify.cookie to the vmid
>  src/Makefile          |   1 -
>  src/PVE/LXC.pm        | 116 ++++++++++++++++++++++++++++++++++++------
>  src/PVE/LXC/Config.pm |   8 +++
>  3 files changed, 109 insertions(+), 16 deletions(-)

applied series, much thanks! I dropped the "add a check_kernel_release helper"
and added it to pve-common's procfs, where we had already an "get parsed kernel
version", and squashed the use of that in your "mask 'mknod' feature by kernel
version" patch, FYI.

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