Landlock for sandboxing containers

Good day,=0A=
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I am investigating the feasibility of integrating Landlock into a container=
 sandboxing utility that I am developing (https://github.com/Gerharddc/litt=
erbox). Essentially Litterbox just makes it easier to setup sandboxed conta=
iners for use as reproducible development environments. The idea here is to=
 shield a host system from anything malicious that might show up inside a d=
evelopment environment.=0A=
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Since Litterbox is built on Podman, my original plan was to use it's built-=
in support for SELinux policies in conjunction with Udica for policy genera=
tion. However, since learning about Landlock, it seems that it would be muc=
h easier to integrate and also more cross-platform (given that SELinux supp=
ort is rare amongst distros). =A0=0A=
=0A=
After reading https://landlock.io/talks/2024-06-06_landlock-article.pdf, La=
ndlock seems very well suited for this purpose. The only thing I am still s=
truggling to wrap my head around is how Landlock integrates with mount name=
spaces and the implication of that for containers. If I understand correctl=
y, it is currently not possible to enter a mount namespace after entering a=
 sandbox. Hence, I would somehow enter the sandbox only after entering the =
container. Is this understanding correct? If so, I suspect I would need to =
extend Podman itself to do so properly since relying on code inside the con=
tainer to enter the sandbox on startup seems like something that could easi=
ly be attacked.=0A=
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Any additional thoughts or suggestions on this endeavour would be greatly a=
ppreciated!=0A=
=0A=
Kind regards,=0A=
Gerhard de Clercq=