2 Commits

Author	SHA1	Message	Date
Mickaël Salaün	ae271c1b14	landlock: Add ruleset and domain management ... A Landlock ruleset is mainly a red-black tree with Landlock rules as nodes. This enables quick update and lookup to match a requested access, e.g. to a file. A ruleset is usable through a dedicated file descriptor (cf. following commit implementing syscalls) which enables a process to create and populate a ruleset with new rules. A domain is a ruleset tied to a set of processes. This group of rules defines the security policy enforced on these processes and their future children. A domain can transition to a new domain which is the intersection of all its constraints and those of a ruleset provided by the current process. This modification only impact the current process. This means that a process can only gain more constraints (i.e. lose accesses) over time. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20210422154123.13086-3-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>	2021-04-22 12:22:10 -07:00
Mickaël Salaün	90945448e9	landlock: Add object management ... A Landlock object enables to identify a kernel object (e.g. an inode). A Landlock rule is a set of access rights allowed on an object. Rules are grouped in rulesets that may be tied to a set of processes (i.e. subjects) to enforce a scoped access-control (i.e. a domain). Because Landlock's goal is to empower any process (especially unprivileged ones) to sandbox themselves, we cannot rely on a system-wide object identification such as file extended attributes. Indeed, we need innocuous, composable and modular access-controls. The main challenge with these constraints is to identify kernel objects while this identification is useful (i.e. when a security policy makes use of this object). But this identification data should be freed once no policy is using it. This ephemeral tagging should not and may not be written in the filesystem. We then need to manage the lifetime of a rule according to the lifetime of its objects. To avoid a global lock, this implementation make use of RCU and counters to safely reference objects. A following commit uses this generic object management for inodes. Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422154123.13086-2-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>	2021-04-22 12:22:10 -07:00